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国外数据库各学科高被引论文TOP5

2015-01-30

中国学术期刊文摘 2015年3期
关键词:出版物邮箱来源

高影响力文章

国外数据库各学科高被引论文TOP5

数据来源:Web of Science文献出版时间:2013.1—2014.11检索时间:2014.12.1

ENGINEERING PETROLEUM 石油工程

被引频次: 8

来源出版物: Journal of Petroleum Science and Engineering , 2013, 109: 364-392联系邮箱: Olajire, AA; olajireaa@yahoo.com

被引频次: 7

An Improved Method for the Determination of Petroleum Hydrocarbons From Soil Using a Simple Ultrasonic Extraction and Fourier Transform Infrared Spectrophotometry

Couto, MN; Borges, JR; Guedes, P; et al.

Abstract: An environmentally friendly, cheap, and quick method for total petroleum hydrocarbons determination in solid matrixes(soil and sediments)is described. The method involves a simple extraction process(ultrasonic bath)and requires reduced amounts of solvent and solid sample. The analysis is carried out by Fourier transform infrared spectrophotometry. Detection limits were 63 or 24 mg kg-1depending on the cell path length(10 or 40 mm, respectively). The method is suitable for application in weathered contaminated soils, which usually presents low availability of contaminants and seems to be a good choice, for instance, for monitoring evolution of soil or sediment recovering during a decontamination process.

Keywords: natural attenuation; oil; validation; grease; water

来源出版物: Petroleum Science and Technology , 2014, 32(4): 426-432联系邮箱: Couto, MN; maria.couto@fc.up.pt

被引频次: 7

CO2Injection in Vertical and Horizontal Cores: Measurements and Numerical Simulation

Moortgat, J; Firoozabadi, A; Li, ZD; et al.

Abstract: In certain high-pressure and low-temperature reservoirs, the density of CO2may be substantially higher than the oil density. Upon mixing of CO2and oil, a gas phase with a high content of methane(C-1)may also appear. When the C-1 content is high, this gas phase may have a lower density than the oil. In relation to this phenomenon, we have conducted three comprehensive experiments studying CO2injection from the top and bottom of a vertical core and injection in a horizontal core. The injection rate is 1 PV/day. This low rate allows the study of diffusion. The core diameter used in this work is 3.8 cm and the length is 27.3 cm. The tests are conducted at a pressure of 441 bar and a temperature of 60 degrees C. At 2.6 hydrocarbon pore volume injection(PVT), the coreflood results give a recovery of 98% for bottom injection, 84% for top injection, and 92% for horizontal injection. We have also conducted an extensive set of measurements to determine swelling, viscosity, and density for the calibration of an equation of state. We simulate the experiments using a state-of-the-art higher-order finite-element three-phase compositional model. The simulations suggest that the endpoint relative permeability of the CO2-rich phase may be lower than the oil phase. The results also show that Fickian diffusion should be taken into account, but that the diffusion coefficients are reduced, because the CO2/oil mixtures are in the near-critical region for much of the injection. Even for a horizontal core there is a considerable gravity effect. One main conclusion is that there may be vast differences between CO2injection in a 1D slim tube and in a core where there may be a 2D flow. A related conclusion is that analysis of CO2coreflooding may provide importantparameters for field-scale problems.

Keywords: discontinuous galerkin; fractured media; mixed methods; diffusion

来源出版物: SPE Journal , 2013, 18(2): 331-344联系邮箱: jmoortgat@rerinst.org

被引频次: 7

Secondary accumulation of hydrocarbons in Carboniferous reservoirs in the northern Tarim Basin, China

Zhu, GY; Zhang, SC; Su, J; et al.

Abstract: Many oil and gas fields have been discovered in Carboniferous in the northern Tarim Basin. The oils and gases produced from the fields show great differences in their physical and geochemical properties. However, their origin and accumulation process have not been well studied even as they become a focus of exploration. Through comprehensive geological and geochemical analysis of the oils and gases, it is recognized that the oils were generated from Mid-Upper Ordovician source rocks, migrated from paleo-oil-accumulations in Ordovician, and were biodegraded to produce different heavy oils before the late Hercynian orogeny(about 250 Ma), so that the oils in the Carboniferous are secondary oil accumulations. Since the Yanshan orogeny(about 86-94 Ma), along with the quick formation of the Kuqa foreland basin, Carboniferous structures were reversed gradually from south dip to north dip, resulting in the Carboniferous nose-shaped traps. During the reversed, faults acted as migration paths connecting underlying Ordovician reservoirs to Carboniferous reservoirs. During the late period of the Himalayan orogeny(20-2 Ma), the Ordovician source rocks were buried so that this achieved level high maturity and generated gas in the eastern part of North Tarim, which resulted in gas accumulations in the eastern part of the studied area, where gas and condensate oil were discovered. The accumulation process of the secondary Carboniferous oil and gas was demonstrated by biomarker compositions, homogeneration temperatures of fluid inclusions and authigenic illite K-Ar dating analyses. Therefore, this conclusion of secondary accumulations of oil and gas in the Carboniferous reservoirs is significant for oil and gas exploration in the northern Tarim.

Keywords: source rock correlations; petroleum migration; nw china; molecular fossils; oil saturation; crude oils; marine oil; part i; pathways; losses

来源出版物: Journal of Petroleum Science and Engineering , 2013, 102: 10-26

联系邮箱: Zhu, GY; zhuguangyou@petrochina.com.cn

被引频次: 6

Modeling of fault reactivation and induced seismicity during hydraulic fracturing of shale-gas reservoirs

Rutqvist, J; Rinaldi, AP; Cappa, F; et al.

Abstract: We have conducted numerical simulation studies to assess the potential for injection-induced fault reactivation and notable seismic events associated with shale-gas hydraulic fracturing operations. The modeling is generally tuned toward conditions usually encountered in the Marcellus shale play in the Northeastern US at an approximate depth of 1500 m(similar to 4500 ft). Our modeling simulations indicate that when faults are present, micro-seismic events are possible, the magnitude of which is somewhat larger than the one associated with micro-seismic events originating from regular hydraulic fracturing because of the larger surface area that is available for rupture. The results of our simulations indicated fault rupture lengths of about 10-20 m, which, in rare cases, can extend to over 100 m, depending on the fault permeability, the in situ stress field, and the fault strength properties. In addition to a single event rupture length of 10-20 m, repeated events and aseismic slip amounted to a total rupture length of 50 m, along with a shear offset displacement of less than 0.01 m. This indicates that the possibility of hydraulically induced fractures at great depth(thousands of meters)causing activation of faults and creation of a new flow path that can reach shallow groundwater resources(or even the surface)is remote. The expected low permeability of faults in producible shale is clearly a limiting factor for the possible rupture length and seismic magnitude. In fact, for a fault that is initially nearly-impermeable, the only possibility of a larger fault slip event would be opening by hydraulic fracturing; this would allow pressure to penetrate the matrix along the fault and to reduce the frictional strength over a sufficiently large fault surface patch. However, our simulation results show that if the fault is initially impermeable, hydraulic fracturing along the fault results in numerous small micro-seismic events along with the propagation, effectively preventing larger events from occurring. Nevertheless, care should be taken with continuous monitoring of induced seismicity during the entire injection process to detect any runaway fracturing along faults. Published by Elsevier B.V.

Keywords: pore pressure excess; fluid-flow; appalachian stress; CO2injection; permeability; leakage; rock; sequestration; earthquakes;maintenance

来源出版物: Journal of Petroleum Science and Engineering , 2013, 107: 31-44联系邮箱: Rutqvist, J; Jrutqvist@lb.gov

ENTOMOLOGY 昆虫学

被引频次: 68

Odorant Reception in Insects: Roles of Receptors, Binding Proteins, and Degrading Enzymes

Leal, WS

Abstract: Our knowledge of the molecular basis of odorant reception in insects has grown exponentially over the past decade. Odorantreceptors(ORs)from moths, fruit flies, mosquitoes, and the honey bees have been deorphanized, odorant-degrading enzymes(ODEs)have been isolated, and the functions of odorant-binding proteins(OBPs)have been unveiled. OBPs contribute to the sensitivity of the olfactory system by transporting odorants through the sensillar lymph, but there are competing hypotheses on how they act at the end of the journey. A few ODEs that have been demonstrated to degrade odorants rapidly may act in signal inactivation alone or in combination with other molecular traps. Although ORs in Drosophila melanogaster respond to multiple odorants and seem to work in combinatorial code involving both periphery and antennal lobes, reception of sex pheromones by moth ORs suggests that their labeled lines rely heavily on selectivity at the periphery.

Keywords: southern house mosquito; pheromone-sensitive neurons; navel orangeworm moth; bombyx-mori; antheraea-polyphemus; anopheles-gambiae; sex-pheromone; olfactory receptors; drosophila-melanogaster; crystal-structure

来源出版物: Annual Review of Entomology, 2013, 58: 373-391联系邮箱: Leal, WS; wsleal@ucdavis.edu

被引频次: 57

The Juvenile Hormone Signaling Pathway in Insect Development

Jindra, M; Palli, SR; Riddiford, LM

Abstract: The molecular action of juvenile hormone(JH), a regulator of vital importance to insects, was until recently regarded as a mystery. The past few years have seen an explosion of studies of JH signaling, sparked by a finding that a JH-resistance gene, Methoprene-tolerant(Met), plays a critical role in insect metamorphosis. Here, we summarize the recently acquired knowledge on the capacity of Met to bind JH, which has been mapped to a particular ligand-binding domain, thus establishing this bHLH-PAS protein as a novel type of an intracellular hormone receptor. Next, we consider the significance of JH-dependent interactions of Met with other transcription factors and signaling pathways. We examine the regulation and biological roles of genes acting downstream of JH and Met in insect metamorphosis. Finally, we discuss the current gaps in our understanding of JH action and outline directions for future research.

Keywords: red flour beetle; rhodnius-prolixus hemiptera; larval-pupal metamorphosis; transcription factor broad; ftz-f1 nuclear receptor;methoprene-tolerant met; ligand-binding domain; retinoid-x-receptors; kruppel homolog 1; bhlh-pas family

来源出版物: Annual Review of Entomology, 2013, 58: 181-204联系邮箱: Riddiford, LM; riddifordl@janelia.hhmi.org

被引频次: 42

Diamondback Moth Ecology and Management: Problems, Progress, and Prospects

Furlong, MJ; Wright, DJ; Dosdall, LM

Abstract: Agricultural intensification and greater production of Brassica vegetable and oilseed crops over the past two decades have increased the pest status of the diamondback moth(DBM), Plutella xylostella L., and it is now estimated to cost the world economy US$4-5 billion annually. Our understanding of some fundamental aspects of DBM biology and ecology, particularly host plant relationships, tritrophic interactions, and migration, has improved considerably but knowledge of other aspects, e. g., its global distribution and relative abundance, remains surprisingly limited. Biological control still focuses almost exclusively on a few species of hymenopteran parasitoids. Although these can be remarkably effective, insecticides continue to form the basis of management; their inappropriate use disrupts parasitoids and has resulted in field resistance to all available products. Improved ecological understanding and the availability of a series of highly effective selective insecticides throughout the 1990s provided the basis for sustainable and economically viable integrated pest management(IPM)approaches. However, repeated reversion to scheduled insecticide applications has resulted in resistance to these and more recently introduced compounds and the breakdown of IPM programs. Proven technologies for the sustainable management of DBM currently exist, but overcoming the barriers to their sustained adoption remains an enormous challenge.

Keywords: plutella-xylostella lepidoptera; parasitoid cotesia-plutellae; diadegma species hymenoptera; thuringiensis toxin cry1ac; plant nutritional quality; field-evolved resistance; south-east queensland; different host plants; bacillus-thuringiensis; insecticide resistance

来源出版物: Annual Review of Entomology, 2013, 58: 517联系邮箱: Furlong, MJ; m.furlong@uq.edu.au

被引频次: 38

Spider-Venom Peptides: Structure, Pharmacology, and Potential for Control of Insect Pests

King, GF; Hardy, MC

Abstract: Spider venoms are an incredibly rich source of disulfide-rich insecticidal peptides that have been tuned over millions of years to target a wide range of receptors and ion channels in the insect nervous system. These peptides can act individually, or as part of larger toxin cabals, to rapidly immobilize envenomated prey owing to their debilitating effects on nervous system function. Most of these peptides contain a unique arrangement of disulfide bonds that provides them with extreme resistance to proteases. As a result, these peptides are highly stable in the insect gut and hemolymph and many of them are orally active. Thus, spider-venom peptides can be used as stand-alone bioinsecticides, or transgenes encoding these peptides can be used to engineer insect-resistant crops or enhanced entomopathogens. We critically review the potential of spider-venom peptides to control insect pests and highlight their advantages and disadvantages compared with con-ventional chemical insecticides.

Keywords: funnel-web spiders; alpha-latrotoxin; snowdrop lectin; in-vitro; toxins; neurotoxins; evolution; channels; scorpion; malaria

来源出版物: Annual Review of Entomology, 2013, 58: 475-496联系邮箱: King, GF; glenn.king@imb.uq.edu.au

被引频次: 34

Data Processing System(DPS)software with experimental design, statistical analysis and data mining developed for use in entomological research

Tang, QY; Zhang, CX

Abstract: A comprehensive but simple-to-use software package called DPS(Data Processing System)has been developed to execute a range of standard numerical analyses and operations used in experimental design, statistics and data mining. This program runs on standard Windows computers. Many of the functions are specific to entomological and other biological research and are not found in standard statistical software. This paper presents applications of DPS to experimental design, statistical analysis and data mining in entomology.

Keywords: single-nucleocapsid nucleopolyhedrovirus; artificial neural-network; budded virus production; soil

来源出版物: Insect Science , 2013, 20(2): 254-260联系邮箱: Tang, QY; qytang@zju.edu.cn

ENVIRONMENTAL SCIENCES 环境科学

被引频次: 184

Low-temperature processed meso-superstructured to thin-film perovskite solar cells

Ball, JM; Lee, MM; Hey, A; et al.

Abstract: We have reduced the processing temperature of the bulk absorber layer in CH3NH3PbI3-xClx perovskite solar cells from 500 to<150 degrees C and achieved power conversion efficiencies up to 12.3%. Remarkably, we find that devices with planar thin-film architecture, where the ambipolar perovskite transports both holes and electrons, convert the absorbed photons into collected charge with close to 100% efficiency.

Keywords: organometal halide perovskites; high-efficiency; photovoltaic cells; low-cost; TiO2; performance

来源出版物: Energy & Environmental Science , 2013, 6(6): 1739-1743联系邮箱: Ball, JM; h.snaith1@physics.ox.ac.uk

被引频次: 142

3D carbon based nanostructures for advanced supercapacitors

Jiang, H; Lee, PS; Li, CZ

Abstract: Supercapacitors have attracted intense attention due to their great potential to meet the demand of both high energy density and power density in many advanced technologies. Various carbon-based nanocomposites are currently pursued as supercapacitor electrodes because of the synergistic effect between carbon(high power density)and pseudo-capacitive nanomaterials(high energy density). This feature article aims to review most recent progress on 3D(3D)carbon based nanostructures for advanced supercapacitor applications in view of their structural intertwinement which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The carbon nanostructures comprise of CNTs-based networks, graphene-based architectures, hierarchical porous carbon-based nanostructures and other even more complex carbon-based 3D configurations. Their advantages and disadvantages are compared and summarized based on the results published in the literature. In addition, we also discuss and view the ongoing trends in materials development for advanced supercapacitors.

Keywords: capacitive energy-storage; double-layer capacitors; ordered mesoporous carbons; electrochemical capacitors; nanotube electrodes; nanowire composites; nanoporous carbon; graphene; performance; oxide

来源出版物: Energy & Environmental Science , 2013, 6(1): 41-53联系邮箱: Jiang, H; czli@ecust.edu.cn

被引频次: 122

Characterising performance of environmental models

Bennett, ND; Croke, BFW; Guariso, G; et al.

Abstract: In order to use environmental models effectively for management and decision-making, it is vital to establish an appropriate level of confidence in their performance. This paper reviews techniques available across various fields for characterising the performance of environmental models with focus on numerical, graphical and qualitative methods. General classes of direct value comparison, coupling real and modelled values, preserving data patterns, indirect metrics based on parameter values, and data transformations are discussed. In practice environmental modelling requires the use and implementation of workflows that combine several methods, tailored to the model purpose and dependent upon the data and information available. A five-step procedure for performance evaluation of models is suggested,with the key elements including:(i)(re)assessment of the model's aim, scale and scope;(ii)characterisation of the data for calibration andtesting;(iii)visual and other analysis to detect under- or non-modelled behaviour and to gain an overview of overall performance;(iv)selection of basic performance criteria; and(v)consideration of more advanced methods to handle problems such as systematic divergence between modelled and observed values.

Keywords: rainfall-runoff models; sensitivity-analysis; hydrological models; parameter-estimation; ecological models; standardized assessment; simulation-models; quality-assurance; dispersion model; wavelet analysis

来源出版物: Environmental Modelling & Software , 2013, 40: 1-20联系邮箱: Jakeman, AJ; tony.jakeman@anu.edu.au

被引频次: 117

Room-temperature stationary sodium-ion batteries for large-scale electric energy storage

Pan, HL; Hu, YS; Chen, LQ

Abstract: Room-temperature stationary sodium-ion batteries have attracted great attention particularly in large-scale electric energy storage applications for renewable energy and smart grid because of the huge abundant sodium resources and low cost. In this article, a variety of electrode materials including cathodes and anodes as well as electrolytes for room-temperature stationary sodium-ion batteries are briefly reviewed. We compare the difference in storage behavior between Na and Li in their analogous electrodes and summarize the sodium storage mechanisms in the available electrode materials. This review also includes some new results from our group and our thoughts on developing new materials. Some perspectives and directions on designing better materials for practical applications are pointed out based on knowledge from the literature and our experience. Through this extensive literature review, the search for suitable electrode and electrolyte materials for stationary sodium-ion batteries is still challenging. However, after intensive research efforts, we believe that low-cost,long-life and room-temperature sodium-ion batteries would be promising for applications in large-scale energy storage system in the near future.

Keywords: rechargeable lithium batteries; long cycle life; oxide intergrowth electrodes; performance anode material; superior rate capability; rate cathode material; x-ray-diffraction; high-capacity; electrochemical properties; low-cost

来源出版物: Energy & Environmental Science , 2013, 6(8): 2338-2360联系邮箱: Pan, HL; yshu@aphy.iphy.ac.cn

被引频次: 101

Highly efficient dye-sensitized solar cells: progress and future challenges

Zhang, SF; Yang, XD; Numata, YH; et al.

Abstract: High energy conversion efficiency is one of the most important keys to the commercialization of dye-sensitized solar cells(DSCs)in the huge electricity generation market. According to our experience in the persistent efforts that helped to achieve high efficiency DSCs, we selectively review the major progress of improving the energy conversion efficiency of DSCs which may be useful for future applications. We start the discussion from modelling the device by macroscopic equivalent circuit and then highlight some approaches to improve the device performance, such as the molecular engineering of novel dye sensitizers and light trapping effect, tuning the potential of redox shuttles and surface passivation of photoelectrodes, and optimizing the resistance. Finally, we illustrate a roadmap of possible future directions of DSCs with the challenges of how to further improve the efficiency to accelerate the progress in the commercialization of DSCs.

Keywords: nanocrystalline TiO2films; high-conversion-efficiency; charge-transfer sensitizers; open-circuit photovoltage; near-ir sensitization; free organic-dyes; nanostructured TiO2; molecular design; cyanine dyes; co-sensitization

来源出版物: Energy & Environmental Science , 2013, 6(5): 1443-1464联系邮箱: Zhang, SF; HAN.liyuan@nims.go.jp

ENVIRONMENTAL STUDIES 环境研究

被引频次: 85

Increasing drought under global warming in observations and models

Dai, AG

Abstract: Historical records of precipitation, streamflow and drought indices all show increased aridity since 1950 over many land areas(1,2). Analyses of model-simulated soil moisture(3,4), drought indices(1,5,6)and precipitation-minus-evaporation(7)suggest increased risk of drought in the twenty-first century. There are, however, large differences in the observed and model-simulated drying patterns(1,2,6). Reconciling these differences is necessary before the model predictions can be trusted. Previous studies(8-12)show that changes in sea surface temperatures have large influences on land precipitation and the inability of the coupled models to reproduce many observed regional precipitation changes is linked to the lack of the observed, largely natural change patterns in sea surface temperatures in coupled model simulations(13). Here I show that the models reproduce not only the influence of El Nino-Southern Oscillation on drought over land, but also the observed global mean aridity trend from 1923 to 2010. Regional differences in observed and model-simulated aridity changes result mainly from natural variations in tropical sea surface temperatures that are often not captured by the coupled models. Theunforced natural variations vary among model runs owing to different initial conditions and thus are irreproducible. I conclude that the observed global aridity changes up to 2010 are consistent with model predictions, which suggest severe and widespread droughts in the next 30-90 years over many land areas resulting from either decreased precipitation and/or increased evaporation.

Keywords: interdecadal climate variability; future drought; north-america; sahel drought; temperature; patterns; rainfall; precipitation;20th-century; simulations

来源出版物: Nature Climate Change , 2013, 3(1): 52-58联系邮箱: Dai, AG; adai@ucar.edu

被引频次: 77

Robustness and uncertainties in the new CMIP5 climate model projections

Knutti, R; Sedlacek, J

Abstract: Estimates of impacts from anthropogenic climate change rely on projections from climate models. Uncertainties in those have often been a limiting factor, in particular on local scales. A new generation of more complex models running scenarios for the upcoming Intergovernmental Panel on Climate Change Fifth Assessment Report(IPCC AR5)is widely, and perhaps naively, expected to provide more detailed and more certain projections. Here we show that projected global temperature change from the new models is remarkably similar to that from those used in IPCC AR4 after accounting for the different underlying scenarios. The spatial patterns of temperature and precipitation change are also very consistent. Interestingly, the local model spread has not changed much despite substantial model development and a massive increase in computational capacity. Part of this model spread is irreducible owing to internal variability in the climate system, yet there is also uncertainty from model differences that can potentially be eliminated. We argue that defining progress in climate modelling in terms of narrowing uncertainties is too limited. Models improve, representing more processes in greater detail. This implies greater confidence in their projections, but convergence may remain slow. The uncertainties should not stop decisions being made.

Keywords: carbon-cycle models; atmosphere-ocean; simpler model; temperature; sensitivity

来源出版物: Nature Climate Change , 2013, 3(4): 369-373联系邮箱: Knutti, R; reto.knutti@env.ethz.ch

被引频次: 55

Temperature as a potent driver of regional forest drought stress and tree mortality

Williams, AP; Allen, CD; Macalady, AK; et al.

Abstract: As the climate changes, drought may reduce tree productivity and survival across many forest ecosystems; however, the relative influence of specific climate parameters on forest decline is poorly understood. We derive a forest drought-stress index(FDSI)for the southwestern United States using a comprehensive tree-ring data set representing AD 1000-2007. The FDSI is approximately equally influenced by the warm-season vapour-pressure deficit(largely controlled by temperature)and cold-season precipitation, together explaining 82% of the FDSI variability. Correspondence between the FDSI and measures of forest productivity, mortality, bark-beetle outbreak and wildfire validate the FDSI as a holistic forest-vigour indicator. If the vapour-pressure deficit continues increasing as projected by climate models, the mean forest drought-stress by the 2050s will exceed that of the most severe droughts in the past 1000 years. Collectively, the results foreshadow twenty-first-century changes in forest structures and compositions, with transition of forests in the southwestern United States, and perhaps water-limited forests globally, towards distributions unfamiliar to modern civilization.

Keywords: western united-states; climate-change; hydrological cycle; north-america; die-off; variability; mechanisms; increase; sensitivity;reduction

来源出版物: Nature Climate Change , 2013, 3(3): 292-297联系邮箱: Williams, AP; parkwilliams@lanl.gov

被引频次: 53

An extreme climatic event alters marine ecosystem structure in a global biodiversity hotspot

Wernberg, T; Smale, DA; Tuya, F; et al.

Abstract: Extreme climatic events, such as heat waves, are predicted to increase in frequency and magnitude as a consequence of global warming but their ecological effects are poorly understood, particularly in marine ecosystems(1-3). In early 2011, the marine ecosystems along the west coast of Australia-a global hotspot of biodiversity and endemism(4,5)-experienced the highest-magnitude warming event on record. Sea temperatures soared to unprecedented levels and warming anomalies of 2-4 degrees C persisted for more than ten weeks along>2000 km of coastline. We show that biodiversity patterns of temperate seaweeds, sessile invertebrates and demersal fish were significantly different after the warming event, which led to a reduction in the abundance of habitat-forming seaweeds and a subsequent shift in community structure towards a depauperate state and a tropicalization of fish communities. We conclude that extreme climatic events are key drivers of biodiversity patterns and that the frequency and intensity of such episodes have major implications for predictive models of species distribution and ecosystem structure, which are largely based on gradual warming trends.

Keywords: ocean temperature; western-australia; reef fishes; patterns; communities; future; disturbance; resilience; stability; gradient

来源出版物: Nature Climate Change , 2013, 3(1): 78-82联系邮箱: Wernberg, T; thomas.wernberg@uwa.edu.au

被引频次: 50

Temperature and vegetation seasonality diminishment over northern lands

Xu, L; Myneni, RB; Chapin, FS; et al.

Abstract: Global temperature is increasing, especially over northern lands(>50 degrees N), owing to positive feedbacks(1). As this increase is most pronounced in winter, temperature seasonality(S-T)-conventionally defined as the difference between summer and winter temperatures-is diminishing over time(2), a phenomenon that is analogous to its equatorward decline at an annual scale. The initiation, termination and performance of vegetation photosynthetic activity are tied to threshold temperatures(3). Trends in the timing of these thresholds and cumulative temperatures above them may alter vegetation productivity, or modify vegetation seasonality(S-V), over time. The relationship between S-T and S-V is critically examined here with newly improved ground and satellite data sets. The observed diminishment of S-T and S-V, is equivalent to 4 degrees and 7 degrees(5 degrees and 6 degrees)latitudinal shift equatorward during the past 30 years in the Arctic.(boreal)region. Analysis of simulations from 17 state-of-the-art climate models(4)indicates an additional S-T diminishment equivalent to a 20 equatorward shift could occur this century. How S-V will change in response to such large projected S-T declines and the impact this will have on ecosystem services(5)are not well understood. Hence the need for continued monitoring(6)of northern lands as their seasonal temperature profiles evolve to resemble those further south.

Keywords: arctic vegetation; tundra; ecosystems; plant; dynamics

来源出版物: Nature Climate Change , 2013, 3(6): 581-586联系邮箱: Xu, L; xuliang@bu.edu

ERGONOMICS 人体工程学

被引频次: 25

An analysis of symbolic linguistic computing models in decision making

Rodriguez, RM; Martinez, L

Abstract: It is common that experts involved in complex real-world decision problems use natural language for expressing their knowledge in uncertain frameworks. The language is inherent vague, hence probabilistic decision models are not very suitable in such cases. Therefore,other tools such as fuzzy logic and fuzzy linguistic approaches have been successfully used to model and manage such vagueness. The use of linguistic information implies to operate with such a type of information, i.e. processes of computing with words(CWW). Different schemes have been proposed to deal with those processes, and diverse symbolic linguistic computing models have been introduced to accomplish the linguistic computations. In this paper, we overview the relationship between decision making and CWW, and focus on symbolic linguistic computing models that have been widely used in linguistic decision making to analyse if all of them can be considered inside of the CWW paradigm.

Keywords: fuzzy-sets; representation model; site selection; words; systems

来源出版物: International Journal of General Systems , 2013, 42(1): 121-136联系邮箱: Rodriguez, RM; rmrodrig@ujaen.es

被引频次: 19

Critical Human Factor Evaluation of Knowledge Sharing Intention in Taiwanese Enterprises

Chen, CW; Chang, ML; Tseng, CP; et al.

Abstract: Knowledge management(KM)is important in the Taiwan business world. Only 0.1% of SMEs, however, have been guided by the Small and Medium Enterprise Administration(SMEA)to introduce knowledge management from 1993 through 2008. The population of KM-implementing SMEs is low. The climate of knowledge sharing has been recognized as the critical factor to successful KM. According to the research results obtained in this study, relation-based motivation is positively related to one's intention to share knowledge. Individual workers can have increased relation-based motivation to become leaders of SMEs building the culture of interpersonal trust and offering group-based reward mechanisms in an organization. This research can help business managers to identify the motivational elements that can encourage investment and propose pragmatic suggestions for introducing initiatives to reinvigorate the number of SMEs implementing KM in Taiwan.

Keywords: management-systems; communities; performance; stickiness; trust; firm

来源出版物: Human Factors and Ergonomics in Manufacturing & Service Industries , 2013, 23(2): 95-106

联系邮箱: Chen, CW; chengwu@mail.nkmu.edu.tw

被引频次: 12

Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression

Wood, B; Rea, MS; Plitnick, B; et al.

Abstract: Exposure to light from self-luminous displays may be linked to increased risk for sleep disorders because these devices emit optical radiation at short wavelengths, close to the peak sensitivity of melatonin suppression. Thirteen participants experienced three experimental conditions in a within-subjects design to investigate the impact of self-luminous tablet displays on nocturnal melatonin suppres-sion: 1)tablets-only set to the highest brightness, 2)tablets viewed through clear-lens goggles equipped with blue light-emitting diodes that provided 40 lux of 470-nm light at the cornea, and 3)tablets viewed through orange-tinted glasses(dark control; optical radiation <525 nm approximate to 0). Melatonin suppressions after 1-h and 2-h exposures to tablets viewed with the blue light were significantly greater than zero. Suppression levels after 1-h exposure to the tablets-only were not statistically different than zero: however, this difference reached significance after 2 h. Based on these results, display manufacturers can determine how their products will affect melatonin levels and, use model predictions to tune the spectral power distribution of self-luminous devices to increase or to decrease stimulation to the circadian system.

来源出版物: Applied Ergonomics , 2013, 44(2): 237-240联系邮箱: Figueiro, MG; woodb5@rpi.edu

被引频次: 11

Do Team and Individual Debriefs Enhance Performance? A Meta-Analysis

Tannenbaum, SI; Cerasoli, CP

Abstract: Objective: Debriefs(or "after-action reviews")are increasingly used in training and work environments as a means of learning from experience. We sought to unify a fragmented literature and assess the efficacy of debriefs with a quantitative review. Background: Used by the U. S. Army to improve performance for decades, and increasingly in medical, aviation, and other communities, debriefs systematize reflection, discussion, and goal setting to promote experiential learning. Unfortunately, research and theory on debriefing has been spread across diverse disciplines, so it has been difficult to definitively ascertain debriefing effectiveness and how to enhance its effectiveness. Method: We conducted an extensive quantitative meta-analysis across a diverse body of published and unpublished research on team-and individual-level debriefs. Results: Findings from 46 samples(N = 2,136)indicate that on average, debriefs improve effectiveness over a control group by approximately 25%(d =0.67). Average effect sizes were similar for teams and individuals, across simulated and real settings, for within- or between-group control designs, and for medical and nonmedical samples. Meta-analytic methods revealed a bolstering effect of alignment and the potential impact of facilitation and structure. Conclusion: Organizations can improve individual and team performance by approximately 20% to 25% by using properly conducted debriefs. Application: Debriefs are a relatively inexpensive and quick intervention for enhancing performance. Our results lend support for continued and expanded use of debriefing in training and in situ. To gain maximum results, it is important to ensure alignment between participants, focus and intent, and level of measurement.

Keywords: after-event reviews; moderating role; failed experience; cardiac-arrest; effects models; mental models; simulation; feedback;instruction; tests

来源出版物: Human Factors , 2013, 55(1): 231-245联系邮箱: Tannenbaum, SI; scott.tannenbaum@groupoe.com

被引频次: 10

The Relationship between Personality Traits and Sales Force Automation Usage: A Preliminary Study

Chen, CW; Lee, KL; Tseng, CP; et al.

Abstract: Sales force automation(SFA)came to cognition and officially gained momentum in the 1990s(Taylor, 1993). SFA provides salespeople with speedy information access, diminishing the time needed to prepare for calls and cutting down on the number of follow-ups,particularly for urgent need of further information support(Taylor, 1993). This study attempts to look specifically at the utilizationindividual impact link. In particular, the close link of the personality type of the sales representative to the individual performance usage of the sales forces automation systems in the pharmaceutical industry in Taiwan. This study provides insight into how the personality traits of the individual medical representatives of pharmaceutical companies in Taiwan could influence the adoption of innovative technology, the sales force automation system.

Keywords: customer relationship management; briggs type indicator; big 5; job-performance; 5-factor model; information-technology;decision-making; user acceptance; pharmaceutical-industry; executive decisions

来源出版物: Human Factors and Ergonomics in Manufacturing & Service Industries , 2013, 23(3): 243-253

联系邮箱: Chen, CW; chengwu@mail.nkmu.edu.tw

EVOLUTIONARY BIOLOGY 生物进化学

被引频次: 400

MEGA6: Molecular Evolutionary Genetics Analysis Version 6.0

Tamura, K; Stecher, G; Peterson, D; et al.

Abstract: We announce the release of an advanced version of the Molecular Evolutionary Genetics Analysis(MEGA)software, which currently contains facilities for building sequence alignments, inferring phylogenetic histories, and conducting molecular evolutionary analysis. In version 6.0, MEGA now enables the inference of timetrees, as it implements the RelTime method for estimating divergence times for all branching points in a phylogeny. A new Timetree Wizard in MEGA6 facilitates this timetree inference by providing a graphical user interface(GUI)to specify the phylogeny and calibration constraints step-by-step. This version also contains enhanced algorithms tosearch for the optimal trees under evolutionary criteria and implements a more advanced memory management that can double the size of sequence data sets to which MEGA can be applied. Both GUI and command-line versions of MEGA6 can be downloaded from www.megasoftware.net free of charge.

来源出版物: Molecular Biology and Evolution , 2013, 30(12): 2725-2729联系邮箱: Kumar, S; s.kumar@asu.edu

被引频次: 370

MAFFT Multiple Sequence Alignment Software Version 7: Improvements in Performance and Usability

Katoh, K; Standley, DM

Abstract: We report a major update of the MAFFT multiple sequence alignment program. This version has several new features, including options for adding unaligned sequences into an existing alignment, adjustment of direction in nucleotide alignment, constrained alignment and parallel processing, which were implemented after the previous major update. This report shows actual examples to explain how these features work, alone and in combination. Some examples incorrectly aligned by MAFFT are also shown to clarify its limitations. We discuss how to avoid misalignments, and our ongoing efforts to overcome such limitations.

Keywords: protein sequences; unaligned sequences; rna sequences; database; tree; algorithm; accuracy; clustal; information; sensitivity

来源出版物: Molecular Biology and Evolution , 2013, 30(4): 772-780联系邮箱: Katoh, K; kazutaka.katoh@aist.go.jp

被引频次: 150

Hybridization and speciation

Abbott, R; Albach, D; Ansell, S; et al.

Abstract: Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow and recombination. It may accelerate speciation via adaptive introgression or cause near-instantaneous speciation by allopolyploidization. It may have multiple effects at different stages and in different spatial contexts within a single speciation event. We offer a perspective on the context and evolutionary significance of hybridization during speciation, highlighting issues of current interest and debate. In secondary contact zones, it is uncertain if barriers to gene flow will be strengthened or broken down due to recombination and gene flow. Theory and empirical evidence suggest the latter is more likely, except within and around strongly selected genomic regions. Hybridization may contribute to speciation through the formation of new hybrid taxa, whereas introgression of a few loci may promote adaptive divergence and so facilitate speciation. Gene regulatory networks, epigenetic effects and the evolution of selfish genetic material in the genome suggest that the DobzhanskyMuller model of hybrid incompatibilities requires a broader interpretation. Finally, although the incidence of reinforcement remains uncertain, this and other interactions in areas of sympatry may have knock-on effects on speciation both within and outside regions of hybridization.

Keywords: homoploid hybrid speciation; reproductive character displacement; adaptive population divergence; senecio-squalidus asteraceae; adjacent plant-populations; gene-expression divergence; natural-selection; local adaptation; sexual selection; genome duplication

来源出版物: Journal of Evolutionary Biology , 2013, 26(2): 229-246联系邮箱: Butlin, RK; r.k.butlin@sheffield.ac.uk

被引频次: 97

Impacts of biological invasions: what's what and the way forward

Simberloff, D; Martin, JL; Genovesi, P; et al.

Abstract: Study of the impacts of biological invasions, a pervasive component of global change, has generated remarkable understanding of the mechanisms and consequences of the spread of introduced populations. The growing field of invasion science, poised at a crossroads where ecology, social sciences, resource management, and public perception meet, is increasingly exposed to critical scrutiny from several perspectives. Although the rate of biological invasions, elucidation of their consequences, and knowledge about mitigation are growing rapidly, the very need for invasion science is disputed. Here, we highlight recent progress in understanding invasion impacts and management, and discuss the challenges that the discipline faces in its science and interactions with society.

Keywords: exotic plant invasions; fresh-water fish; introduced predators; ecosystem responses; ecological impacts; biodiversity; forests;communities; islands; rats

来源出版物: Trends in Ecology & Evolution , 2013, 28(1): 58-66联系邮箱: Simberloff, D; dsimberloff@utk.edu

被引频次: 66

On the Immortality of Television Sets: "Function" in the Human Genome According to the Evolution-Free Gospel of ENCODE

Graur, D; Zheng, YC; Price, N; et al.

Abstract: A recent slew of ENCyclopedia Of DNA Elements(ENCODE)Consortium publications, specifically the article signed by all Consortium members, put forward the idea that more than 80% of the human genome is functional. This claim flies in the face of current estimates according to which the fraction of the genome that is evolutionarily conserved through purifying selection is less than 10%. Thus,according to the ENCODE Consortium, a biological function can be maintained indefinitely without selection, which implies that at least 80 - 10=70% of the genome is perfectly invulnerable to deleterious mutations, either because no mutation can ever occur in these "functional" regions or because no mutation in these regions can ever be deleterious. This absurd conclusion was reached through various means,chiefly by employing the seldom used "causal role" definition of biological function and then applying it inconsistently to different biochemical properties, by committing a logical fallacy known as "affirming the consequent," by failing to appreciate the crucial difference between "junk DNA" and "garbage DNA," by using analytical methods that yield biased errors and inflate estimates of functionality, by favoring statistical sensitivity over specificity, and by emphasizing statistical significance rather than the magnitude of the effect. Here, we detail the many logical and methodological transgressions involved in assigning functionality to almost every nucleotide in the human genome. The ENCODE results were predicted by one of its authors to necessitate the rewriting of textbooks. We agree, many textbooks dealing with marketing, mass-media hype, and public relations may well have to be rewritten.

Keywords: factor-binding sites; junk dna; gene-expression; transcriptional noise; regulatory sequences; mammalian-cells; wide analysis;elements; pseudogene; selection

来源出版物: Genome Biology and Evolution , 2013, 5(3): 578-590联系邮箱: Graur, D; dgraur@uh.edu

FISHERIES 渔业

被引频次: 43

Stock synthesis: A biological and statistical framework for fish stock assessment and fishery management

Methot, RD; Wetzel, CR

Abstract: Stock synthesis(SS)is a statistical age-structured population modeling framework that has been applied in a wide variety of fish assessments globally. The framework is highly scalable from data-weak situations where it operates as an age-structured production model,to complex situations where it can flexibly incorporate multiple data sources and account for biological and environmental processes. SS implements compensatory population dynamics through use of a function relating mean recruitment to spawner reproductive output. This function enhances the ability of SS to operate in data-weak situations and enables it to estimate fishery management quantities such as fishing rates that would provide for maximum sustainable yield and to employ these rates in forecasts of potential yield and future stock status. Complex model configurations such as multiple areas and multiple growth morphs are possible, tag-recapture data can be used to aid estimation of movement rates among areas, and most parameters can change over time in response to environmental and ecosystem factors. SS is coded using Auto-Differentiation Model Builder, so inherits its powerful capability to efficiently estimate hundreds of parameters using either maximum likelihood or Bayesian inference. Output processing, principally through a package developed in R, enables rapid model diagnosis. Details of the underlying population dynamics and the statistical framework used within SS are provided.

Keywords: assessment models; reduction analysis; age data; catch; selectivity; parameters; mortality; fecundity; example; curves

来源出版物: Fisheries Research , 2013, 142: 86-99联系邮箱: Methot, RD; richard.methot@noaa.gov

被引频次: 25

Salmon lice - impact on wild salmonids and salmon aquaculture

Torrissen, O; Jones, S; Asche, F; et al.

Abstract: Salmon lice, Lepeophtheirus salmonis, are naturally occurring parasites of salmon in sea water. Intensive salmon farming provides better conditions for parasite growth and transmission compared with natural conditions, creating problems for both the salmon farming industry and, under certain conditions, wild salmonids. Salmon lice originating from farms negatively impact wild stocks of salmonids, although the extent of the impact is a matter of debate. Estimates from Ireland and Norway indicate an odds ratio of 1.1:1-1.2:1 for sea lice treated Atlantic salmon smolt to survive sea migration compared to untreated smolts. This is considered to have a moderate population regulatory effect. The development of resistance against drugs most commonly used to treat salmon lice is a serious concern for both wild and farmed fish. Several large initiatives have been taken to encourage the development of new strategies, such as vaccines and novel drugs, for the treatment or removal of salmon lice from farmed fish. The newly sequenced salmon louse genome will be an important tool in this work. The use of cleaner fish has emerged as a robust method for controlling salmon lice, and aquaculture production of wrasse is important towards this aim. Salmon lice have large economic consequences for the salmon industry, both as direct costs for the prevention and treatment, but also indirectly through negative public opinion.

Keywords: louse lepeophtheirus-salmonis; farmed atlantic salmon; juvenile pink salmon; sea lice; salar l.; emamectin benzoate; british-columbia; west-coast; oncorhynchus-gorbuscha; gene-expression

来源出版物: Journal of Fish Diseases , 2013, 36(3): 171-194联系邮箱: Torrissen, O; olet@imr.no

被引频次: 24

Sea cucumber fisheries: global analysis of stocks, management measures and drivers of overfishing

Purcell, SW; Mercier, A; Conand, C; et al.

Abstract: Worldwide, most sea cucumber fisheries are ineffectively managed, leading to declining stocks and potentially eroding the resilience of fisheries. We analyse trends in catches, fishery status, fishing participation and regulatory measures among 77 sea cucumber fisheries through data from recent fishery reports and fishery managers. Critical gaps in fisheries biology knowledge of even commonly targeted species undermine the expected success of management strategies. Most tropical fisheries are small-scale, older and typified by numerous(>8)species, whereas temperate fisheries are often emerging, mono-specific and industrialized. Fisher participation data indicated about 3million sea cucumber fishers worldwide. Fisher participation rates were significantly related to the average annual yield. permanova analysis showed that over-exploited and depleted fisheries employed different sets of measures than fisheries with healthier stocks, and a non-metric multidimensional scaling ordination illustrated that a broad set of regulatory measures typified sustainable fisheries. SIMPER and regression tree analyses identified that the dissimilarity was most related to enforcement capacity, number of species harvested, fleet(vessel)controls, limited entry controls and rotational closures. The national Human Development Index was significantly lower in countries with over-exploited and depleted fisheries. Where possible, managers should limit the number of fishers and vessel size and establish short lists of permissible commercial species in multispecies fisheries. Our findings emphasize an imperative to support the enforcement capacity in low-income countries, in which risk of biodiversity loss is exceptionally high. Solutions for greater resilience of sea cucumber stocks must be embedded within those for poverty reduction and alternative livelihood options.

Keywords: social-ecological systems; great-barrier-reef; marine protected areas; small-scale fisheries; coral-reef; cucumaria-frondosa;holothuria-scabra; echinodermata holothuroidea; population-dynamics; aegean sea

来源出版物: Fish and Fisheries , 2013, 14(1): 34-59联系邮箱: Purcell, SW; steven.w.purcell@gmail.com

被引频次: 21

A review of integrated analysis in fisheries stock assessment

Maunder, MN; Punt, AE

Abstract: Limited data, and the requirement to provide science-based advice for exploited populations, have led to the development of statistical methods that combine several sources of information into a single analysis. This approach, "integrated analysis", was first formulated by Fournier and Archibald in 1982. Contemporary use of integrated analysis involves using all available data, in as raw a form as appropriate, in a single analysis. Analyses that were traditionally carried out independently are now conducted simultaneously through likelihood functions that include multiple data sources. For example, the traditional analysis of converting catch-at-length data into catch-at-age data for use in an age-structured population dynamics models can be avoided by including the basic data used in this conversion,length-frequency and conditional age-at-length data, in the likelihood function. This allows for consistency in assumptions and permits the uncertainty associated with both data sources to be propagated to final model outputs, such as catch limits under harvest control rules. The development of the AD Model Builder software has greatly facilitated the use of integrated analyses, and there are now several general stock assessment models(e.g., Stock Synthesis)that allow many data types and model assumptions to be analyzed simultaneously. In this paper, we define integrated analysis, describe its history and development, give several examples, and describe the advantages of and problems with integrated analysis.

Keywords: importance resampling algorithm; virtual population analysis; contradictory data sources; delay-difference model; northern prawn fishery; tasmanian rock lobster; tuna thunnus-maccoyii; at-age data; abundance indexes; general framework

来源出版物: Fisheries Research , 2013, 142: 61-74联系邮箱: Maunder, MN; mmaunder@iattc.org

被引频次: 20

Prophenoloxidase system and its role in shrimp immune responses against major pathogens

Amparyup, P; Charoensapsri, W; Tassanakajon, A

Abstract: The global shrimp industry still faces various serious disease-related problems that are mainly caused by pathogenic bacteria and viruses. Understanding the host defense mechanisms is likely to be beneficial in designing and implementing effective strategies to solve the current and future pathogen-related problems. Melanization, which is performed by phenoloxidase(PO)and controlled by the prophenoloxidase(proPO)activation cascade, plays an important role in the invertebrate immune system in allowing a rapid response to pathogen infection. The activation of the proPO system, by the specific recognition of microorganisms by pattern-recognition proteins(PRPs), triggers a serine proteinase cascade, eventually leading to the cleavage of the inactive proPO to the active PO that functions to produce the melanin and toxic reactive intermediates against invading pathogens. This review highlights the recent discoveries of the critical roles of-the proPO-system in the shrimp immune responses against major pathogens, and emphasizes the functional characterizations of four major groups of genes and proteins in the proPO cascade in penaeid shrimp, that is the PRPs, serine proteinases, proPO and inhibitors.

Keywords: beta-1,3-glucan binding-protein; crayfish pacifastacus-leniusculus; holotrichia-diomphalia larvae; black tiger shrimp; pat-tern-recognition receptor; fresh-water crayfish; pro-phenol-oxidase; penaeus litopenaeus vannamei; induced melanin synthesis; vector anopheles-gambiae

来源出版物: Fish & Shellfish Immunology , 2013, 34(4): 990-1001联系邮箱: Amparyup, P; piti.amp@biotec.or.th

FOOD SCIENCE TECHNOLOGY 食品科技

被引频次: 62

Masked mycotoxins: A review

Berthiller, F; Crews, C; Dall'Asta, C; et al.

Abstract: The aim of this review is to give a comprehensive overview of the current knowledge on plant metabolites of mycotoxins, also called masked mycotoxins. Mycotoxins are secondary fungal metabolites, toxic to human and animals. Toxigenic fungi often grow on edible plants, thus contaminating food and feed. Plants, as living organisms, can alter the chemical structure of mycotoxins as part of their defence against xenobiotics. The extractable conjugated or non-extractable bound mycotoxins formed remain present in the plant tissue but are currently neither routinely screened for in food nor regulated by legislation, thus they may be considered masked. Fusarium mycotoxins(deoxynivalenol, zearalenone, fumonisins, nivalenol, fusarenon-X, T-2 toxin, HT-2 toxin, fusaric acid)are prone to metabolisation or binding by plants, but transformation of other mycotoxins by plants(ochratoxin A, patulin, destruxins)has also been described. Toxicological data are scarce, but several studies highlight the potential threat to consumer safety from these substances. In particular, the possible hydrolysis of masked mycotoxins back to their toxic parents during mammalian digestion raises concerns. Dedicated chapters of this article address plant metabolism as well as the occurrence of masked mycotoxins in food, analytical aspects for their determination, toxicology and their impact on stakeholders.

Keywords: tandem mass-spectrometry; conjugated fusarium mycotoxins; glutathione-s-transferase; cell-suspension cultures; barley hordeum-vulgare; of-the-art; trichothecene mycotoxins; fumonisin b-1; ochratoxin-a; transcriptome analysis

来源出版物: Molecular Nutrition & Food Research , 2013, 57(1): 165-186联系邮箱: Berthiller, F; publications@ilsieurope.be

被引频次: 62

A review on antioxidants, prooxidants and related controversy: Natural and synthetic compounds,screening and analysis methodologies and future perspectives

Carocho, M; Ferreira, ICFR

Abstract: Many studies have been conducted with regard to free radicals, oxidative stress and antioxidant activity of food, giving antioxidants a prominent beneficial role, but, recently many authors have questioned their importance, whilst trying to understand the mechanisms behind oxidative stress. Many scientists defend that regardless of the quantity of ingested antioxidants, the absorption is very limited, and that in some cases prooxidants are beneficial to human health. The detection of antioxidant activity as well as specific antioxidant compounds can be carried out with a large number of different assays, all of them with advantages and disadvantages. The controversy around antioxidant in vivo benefits has become intense in the past few decades and the present review tries to shed some light on research on antioxidants(natural and synthetic)and prooxidants, showing the potential benefits and adverse effects of these opposing events, as well as their mechanisms of action and detection methodologies. It also identifies the limitations of antioxidants and provides a perspective on the likely future trends in this field.

Keywords: simulated gastrointestinal digestion; phenolic-acids; vitamin-c; butylated hydroxytoluene; oxidative stress; liquid-chromatography;lipid-peroxidation; gas-chromatography; biological-systems; capacity assays

来源出版物: Food and Chemical Toxicology , 2013, 51: 15-25联系邮箱: Ferreira, ICFR; iferreira@ipb.pt

被引频次: 34

An overview of the last advances in probiotic and prebiotic field

Saad, N; Delattre, C; Urdaci, M; et al.

Abstract: Probiotics and prebiotics play an important role in human nutrition. In recent years there has been a significant increase in research on the characterization and verification potential health benefits associated with the use of probiotic and prebiotic. The main effects attributed to selected probiotics/prebiotic products have been proved by clinical trials, while others have been acquired on the basis of in vitro tests which require in vivo transposition in order to be validated. The main clinical reports in the literature for the application of probiotic have been done for the treatment of infectious diseases including viral, bacterial or antibiotic associated diarrhoea, relief of chronic bowel inflammatory diseases, immuno-modulation, lowering of serum cholesterol, decreased risk of colon cancer, improve lactose digestion, reduce allergies, and effect on intestinal microbiota. Although the large investigation for the health benefits, information on probiotic species, a specific strain-therapeutic application, and sufficient dosages, is not sufficiently studied to allow practical and rational consumption. Moreover, prebiotic oligosaccharides although provided curative and nutritional values, they are poorly understood in regard to theirorigin, the processes employed to generate them, their fermentation profiles, and dosages required for health effects. The present review summarizes guidelines reported on the literature in regard to clinician or therapeutic trials of probiotic and prebiotic.

Keywords: irritable-bowel-syndrome; lactobacillus-rhamnosus gg; randomized controlled-trial; placebo-controlled trial; inulin-type fructans; intestinal epithelial-cells; glucagon-like peptide-1; chain fatty-acids; antibiotic-associated diarrhea; difficile-associated diarrhea

来源出版物: Lwt-food Science and Technology , 2013, 50(1): 1-16联系邮箱: Saad, N; saad_naima@hotmail.fr

被引频次: 32

Rhodamine and BODIPY chemodosimeters and chemosensors for the detection of Hg2+,based on fluorescence enhancement effects

Culzoni, MJ; de la Pena, AM; Machuca, A; et al.

Abstract: Fluorescent sensors for Hg2+are demonstrating their potential in a variety of fields such as environmental and biological applications. The review focuses on the recent development of rhodamine derivatives in which the spirolactam(non-fluorescent)to ring-opened amide(fluorescent)process was utilized and on the development of BODIPY derivatives in which the photoinduced electron transfer(PET)process was utilized. New trends in the immobilization of the molecular probes on solid supports, as polymers and/or nanostructures, have been emphasized. The different recognition mechanisms used for the signal responses have been analyzed. The spectroscopic properties,reaction media, analytical parameters, interferences by other ions and practical applications have been summarized.

Keywords: plasma-mass spectrometry; aqueous-solution; selective detection; natural-water; living cells; inorganic mercury; molecular logic; fish samples; metal-ions; off-on

来源出版物: Analytical Methods , 2013, 5(1): 30-49

被引频次: 31

High sensitive voltammetric sensor based on Pt/CNTs nanocomposite modified ionic liquid carbon paste electrode for determination of Sudan I in food samples

Elyasi, M; Khalilzadeh, MA; Karimi-Maleh, H

Abstract: In this work, a simple and high sensitivity electrochemical sensor was developed to determine Sudan I based on Pt/CNTs nanocomposite ionic liquid modified carbon paste electrode(Pt/CNTs/ILCPE)using cyclic voltammetry, electrochemical impedance spectroscopy(EIS)and square wave voltammetry(SWV)methods. The novel sensor exhibited an obviously catalytic activity towards the oxidation of Sudan I, which can be confirmed by the increased oxidation peak current and the decreased oxidation peak potential when compared with the bare carbon paste electrode(CPE). The electron transfer coefficient(alpha), diffusion coefficient(D), and charge transfer resistance(R-ct)of Sudan I at the modified electrode were calculated. The linear response range and detection limit were found to be 0.008-600 mu mol L-1 and 0.003 mu mol L-1, respectively. Other species did not interfere with the determination of Sudan I at a surface of propose sensor in the optimum condition. The proposed sensor was successfully applied for the determination of Sudan I in food samples with satisfactory results.

Keywords: membrane potentiometric sensor; pyrolytic-graphite electrode; pvc matrix; electrochemical determination; selective determination; mass-spectrometry; hot chili; uric-acid; nanotubes; chromatography

来源出版物: Food Chemistry , 2013, 141(4): 4311-4317联系邮箱: Khalilzadeh, MA; khalilzadeh73@gmail.com

FORESTRY 林业

被引频次: 65

Climate change, phenology, and phenological control of vegetation feedbacks to the climate system

Richardson, AD; Keenan, TF; Migliavacca, M; et al.

Abstract: Vegetation phenology is highly sensitive to climate change. Phenology also controls many feedbacks of vegetation to the climate system by influencing the seasonality of albedo, surface roughness length, canopy conductance, and fluxes of water, energy, CO2and biogenic volatile organic compounds. In this review, we first discuss the environmental drivers of phenology, and the impacts of climate change on phenology, in different biomes. We then examine the vegetation-climate feedbacks that are mediated by phenology, and assess the potential impact on these feedbacks of shifts in phenology driven by climate change. We finish with an overview of phenological modeling and we suggest ways in which models might be improved using existing data sets. Several key weaknesses in our current understanding emerge from this analysis. First, we need a better understanding of the drivers of phenology, particularly in under-studied biomes(e.g. tropical forests). We do not have a mechanistic understanding of the role of photoperiod, even in well-studied biomes. In all biomes, the factors controlling senescence and dormancy are not well-documented. Second, for the most part(i.e. with the exception of phenology impacts on CO2exchange)we have only a qualitative understanding of the feedbacks between vegetation and climate that are mediated by phenology. We need to quantify the magnitude of these feedbacks, and ensure that they are accurately reproduced by models. Third, weneed to work towards a new understanding of phenological processes that enables progress beyond the modeling paradigms currently in use. Accurate representation of phenological processes in models that couple the land surface to the climate system is particularly important,especially when such models are being used to predict future climate.

Keywords: terrestrial biosphere model; net ecosystem productivity; volatile organic-compounds; northern hardwood forest; carbon-dioxide exchange; spring starting earlier; boreal aspen forest; leaf bud burst; deciduous forest; interannual variability

来源出版物: Agricultural and Forest Meteorology , 2013, 169: 156-173联系邮箱: Richardson, AD; arichardson@oeb.harvard.edu

被引频次: 36

The Agricultural Model Intercomparison and Improvement Project(AgMIP): Protocols and pilot studies

Rosenzweig, C; Jones, JW; Hatfield, JL; et al.

Abstract: The Agricultural Model Intercomparison and Improvement Project(AgMIP)is a major international effort linking the climate,crop, and economic modeling communities with cutting-edge information technology to produce improved crop and economic models and the next generation of climate impact projections for the agricultural sector. The goals of AgMIP are to improve substantially the characterization of world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. Analyses of the agricultural impacts of climate variability and change require a transdisciplinary effort to consistently link state-of-the-art climate scenarios to crop and economic models. Crop model outputs are aggregated as inputs to regional and global economic models to determine regional vulnerabilities, changes in comparative advantage, price effects, and potential adaptation strategies in the agricultural sector. Climate, Crop Modeling, Economics, and Information Technology Team Protocols are presented to guide coordinated climate, crop modeling, economics, and information technology research activities around the world, along with AgMIP Cross-Cutting Themes that address uncertainty, aggregation and scaling, and the development of Representative Agricultural Pathways(RAPs)to enable testing of climate change adaptations in the context of other regional and global trends. The organization of research activities by geographic region and specific crops is described, along with project milestones.

Pilot results demonstrate AgMIP's role in assessing climate impacts with explicit representation of uncertainties in climate scenarios and simulations using crop and economic models. An intercomparison of wheat model simulations near Obregon, Mexico reveals inter-model differences in yield sensitivity to [CO2] with model uncertainty holding approximately steady as concentrations rise, while uncertainty related to choice of crop model increases with rising temperatures. Wheat model simulations with mid-century climate scenarios project a slight decline in absolute yields that is more sensitive to selection of crop model than to global climate model, emissions scenario, or climate scenario downscaling method. A comparison of regional and national-scale economic simulations finds a large sensitivity of projected yield changes to the simulations' resolved scales. Finally, a global economic model intercomparison example demonstrates that improvements in the understanding of agriculture futures arise from integration of the range of uncertainty in crop, climate, and economic modeling results in multi-model assessments.

Keywords: stochastic weather generators; climate-change research; cropgro-soybean model; integrated assessment; us agriculture; system model; elevated CO2; yield; impacts; variability

来源出版物: Agricultural and Forest Meteorology , 2013, 170: 166-182联系邮箱: Rosenzweig, C; cynthia.rosenzweig@nasa.gov

被引频次: 23

A critical discussion of the physics of wood-water interactions

Engelund, ET; Thygesen, LG; Svensson, S; et al.

Abstract: This paper reviews recent findings on wood-water interaction and puts them into context of established knowledge in the field. Several new findings challenge prevalent theories and are critically discussed in an attempt to advance current knowledge and highlight gaps. The focus of this review is put on water in the broadest concept of wood products, that is, the living tree is not considered. Moreover,the review covers the basic wood-water relation, states and transitions. Secondary effects such as the ability of water to alter physical properties of wood are only discussed in cases where there is an influence on state and/or transition.

Keywords: fiber saturation point; differential scanning calorimetry; moisture sorption hysteresis; furfurylated norway spruce; proton magnetic-resonance; independent-domain theory; cell-wall; cellulose microfibril; dimensional changes; tropical hardwoods

来源出版物: Wood Science and Technology , 2013, 47(1): 141-161联系邮箱: Engelund, ET; ete@teknologisk.dk

被引频次: 22

A strategy for quality and uncertainty assessment of long-term eddy-covariance measurements

Mauder, M; Cuntz, M; Drue, C; et al.

Abstract: Eddy-covariance measurements are performed at several hundred sites all over the world on a long-term basis. The gathered data are used to characterise ecosystem exchanges of trace gases, water and energy and to validate or constrain process-based models. There is an increasing demand on standardised and comprehensive quality flagging and uncertainty quantification of these fluxes. In this paper, wereview established quality assessment procedures and present a comprehensive newly composed strategy emphasising tests on high-frequency raw data, expanding existing tests on statistics, fluxes and corrections, plus quantification of errors. Moreover, representativity of fluxes is checked by footprint analysis. This strategy is applied within the recently launched TERENO network of ecosystem observatories, and its robustness is demonstrated for data acquired with different measurement set-ups. Four test data sets from TERENO and one data set from CarboEurope-IP were subjected to this quality assessment. The presented strategy is compared with established quality assessment schemes, and it is demonstrated that unrealistic fluxes are now efficiently excluded while retaining the largest possible amount of high quality data. Additionally, the algorithms applied provide comprehensive, reproducible, qualitative and quantitative uncertainty estimates for users of eddy-covariance flux data.

Keywords: energy-balance closure; analytical footprint model; convective boundary-layer; carboeurope flux data; water-vapor; sonic anemometer; surface-layer; similarity relationships; intermittent turbulence; experiment ebex-2000

来源出版物: Agricultural and Forest Meteorology , 2013, 169: 122-135联系邮箱: Mauder, M; matthias.mauder@kit.edu

被引频次: 20

Xylem embolism threshold for catastrophic hydraulic failure in angiosperm trees

Urli, M; Porte, AJ; Cochard, H; et al.

Abstract: Hydraulic failure is one of the main causes of tree mortality in conditions of severe drought. Resistance to cavitation is known to be strongly related to drought tolerance and species survival in conifers, but the threshold of water-stress-induced embolism leading to catastrophic xylem dysfunction in angiosperms has been little studied. We investigated the link between drought tolerance, survival and xylem cavitation resistance in five angiosperm tree species known to have contrasting desiccation resistance thresholds. We exposed seedlings in a greenhouse to severe drought to generate extreme water stress. We monitored leaf water potential, total plant water loss rate, leaf transpiration, stomatal conductance and CO2assimilation rate during drought exposure and after rewatering(recovery phase). The time required for the recovery of 50% of the maximum value of a given ecophysiological variable after rewatering was used to determine the critical water potential corresponding to the threshold beyond which the plant failed to recover. We also investigated the relationship between this potential and stem xylem cavitation resistance, as assessed from vulnerability curves. This minimum recoverable water potential was consistent between ecophysiological variables and varied considerably between species, from -3.4 to -6.0 MPa. This minimum recoverable water potential was strongly correlated with P-50 and P-88, the pressures inducing 50 and 88% losses of stem hydraulic conductance, respectively. Moreover, the embolism threshold leading to irreversible drought damage was found to be close to 88%, rather than the 50% previously reported for conifers. Hydraulic failure leading to irreversible drought-induced global dysfunction in angiosperm tree species occurred at a very high level of xylem embolism, possibly reflecting the physiological characteristics of their stem water-transport system.

Keywords: change-type drought; pinus-sylvestris l; scots pine; die-off; desiccation-tolerance; fagus-sylvatica; winter embolism; native embolism; mortality; cavitation

来源出版物: Tree Physiology , 2013, 33(7): 672-683联系邮箱: Delzon, S; sylvain.delzon@u-bordeaux1.fr

GASTROENTEROLOGY HEPATOLOGY 胃肠病及肝病

被引频次: 134

Classification of acute pancreatitis-2012: revision of the Atlanta classification and definitions by international consensus

Banks, PA; Bollen, TL; Dervenis, C; et al.

Abstract: Background and objective The Atlanta classification of acute pancreatitis enabled standardised reporting of research and aided communication between clinicians. Deficiencies identified and improved understanding of the disease make a revision necessary.

Methods A web-based consultation was undertaken in 2007 to ensure wide participation of pancreatologists. After an initial meeting, the Working Group sent a draft document to 11 national and international pancreatic associations. This working draft was forwarded to all members. Revisions were made in response to comments, and the web-based consultation was repeated three times. The final consensus was reviewed, and only statements based on published evidence were retained.

Results The revised classification of acute pancreatitis identified two phases of the disease: early and late. Severity is classified as mild,moderate or severe. Mild acute pancreatitis, the most common form, has no organ failure, local or systemic complications and usually resolves in the first week. Moderately severe acute pancreatitis is defined by the presence of transient organ failure, local complications or exacerbation of co-morbid disease. Severe acute pancreatitis is defined by persistent organ failure, that is, organ failure >48 h. Local complications are peripancreatic fluid collections, pancreatic and peripancreatic necrosis(sterile or infected), pseudocyst and walled-off necrosis(sterile or infected). We present a standardised template for reporting CT images.

Conclusions This international, web-based consensus provides clear definitions to classify acute pancreatitis using easily identified clinical and radiologic criteria. The wide consultation among pancreatologists to reach this consensus should encourage widespread adoption.

Keywords: systemic inflammatory response; organ failure; necrotizing pancreatitis; computed-tomography; fluid collections; early prediction; double-blind; necrosis; severity; dysfunction

来源出版物: Gut , 2013, 62(1): 102-111联系邮箱: Sarr, MG; sarr.michael@mayo.edu

被引频次: 126

Triple therapy in treatment-experienced patients with HCV-cirrhosis in a multicentre cohort of the French Early Access Programme(ANRS CO20-CUPIC)-NCT01514890

Hezode, C; Fontaine, H; Dorival, C; et al.

Abstract: Background & Aims: In phase III trials, the safety profile of triple therapy(pegylated interferon/ribavirin with boceprevir or telaprevir)seems to be similar in HCV treatment-experienced cirrhotic and non-cirrhotic patients, but few cirrhotics were included. We report the week 16 safety and efficacy analysis in a cohort of compensated cirrhotics treated in the French Early Access Programme.

Methods: 674 genotype 1 patients, prospectively included, received 48 weeks of triple therapy. The analysis is restricted to 497 patients reaching week 16. Results: A high incidence of serious adverse events(40.0%), and of death and severe complications(severe infection or hepatic decompensation)(6.4%), and a difficult management of anaemia(erythropoietin and transfusion use in 50.7% and 12.1%)were observed. Independent predictors of anaemia <8 g/dl or blood transfusion were: female gender(OR 2.19, 95% CI 1.11-4.33, p = 0.024), no lead-in phase(OR 2.25, 95% CI 1.15-4.39, p = 0.018), age≥65 years(OR 3.04, 95% CI 1.54-6.02, p = 0.0014), haemoglobin level(≤12 g/dl for females,≤13 g/dl for males)(OR 5.30, 95% CI 2.49-11.5, p = 0.0001). Death or severe complications were related to platelets count≤100000 mm3(OR 3.11, 95% CI 1.30-7.41, p = 0.0105)and albumin <35 g/dl(OR 6.33, 95% CI 2.66-15.07, p = 0.0001), with a risk of 44.1% in patients with both. However, the on-treatment virological response was high. Conclusions: The safety profile was poor and patients with platelet count ≤100000 mm3and serum albumin <35 g/L should not be treated with the triple therapy.

Keywords: chronic hepatitis-c; sustained virological response; genotype 1 infection; hepatocellular-carcinoma; peginterferon alpha-2b;virus-infection; plus ribavirin; efficacy; safety; boceprevir

来源出版物: Journal of Hepatology , 2013, 59(3): 434-441联系邮箱: Bronowicki, JP; bronowicki@chu-nancy.fr

被引频次: 121

Global epidemiology of hepatitis C virus infection: New estimates of age-specific antibody to HCV seroprevalence

Hanafiah, KM; Groeger, J; Flaxman, AD; et al.

Abstract: In efforts to inform public health decision makers, the Global Burden of Diseases, Injuries, and Risk Factors 2010(GBD2010)Study aims to estimate the burden of disease using available parameters. This study was conducted to collect and analyze available prevalence data to be used for estimating the hepatitis C virus(HCV)burden of disease. In this systematic review, antibody to HCV(anti-HCV)seroprevalence data from 232 articles were pooled to estimate age-specific seroprevalence curves in 1990 and 2005, and to produce age-standardized prevalence estimates for each of 21 GBD regions using a model-based meta-analysis. This review finds that globally the prevalence and number of people with anti-HCV has increased from 2.3%(95% uncertainty interval [UI]: 2.1%-2.5%)to 2.8%(95% UI: 2.6%-3.1%)and >122 million to >185 million between 1990 and 2005. Central and East Asia and North Africa/Middle East are estimated to have high prevalence(>3.5%); South and Southeast Asia, sub-Saharan Africa, Andean, Central, and Southern Latin America, Caribbean,Oceania, Australasia, and Central, Eastern, and Western Europe have moderate prevalence(1.5%-3.5%); whereas Asia Pacific, Tropical Latin America, and North America have low prevalence(<1.5%). Conclusion: The high prevalence of global HCV infection necessitates renewed efforts in primary prevention, including vaccine development, as well as new approaches to secondary and tertiary prevention to reduce the burden of chronic liver disease and to improve survival for those who already have evidence of liver disease.

Keywords: united-states; prevalence; cirrhosis; area; recommendations; transmission; progression; prevention; donation; payment

来源出版物: Hepatology , 2013, 57(4): 1333-1342联系邮箱: Wiersma, ST; wiersmas@tz.cdc.gov

被引频次: 110

The Oslo definitions for coeliac disease and related terms

Ludvigsson, JF; Leffler, DA; Bai, JC; et al.

Abstract: Objective The literature suggests a lack of consensus on the use of terms related to coeliac disease(CD)and gluten.

Design A multidisciplinary task force of 16 physicians from seven countries used the electronic database PubMed to review the literature for CD-related terms up to January 2011. Teams of physicians then suggested a definition for each term, followed by feedback of these definitions through a web survey on definitions, discussions during a meeting in Oslo and phone conferences. In addition to 'CD', the following descriptors of CD were evaluated(in alphabetical order): asymptomatic, atypical, classical, latent, non-classical, overt, paediatric classical, potential, refractory, silent, subclinical, symptomatic, typical, CD serology, CD autoimmunity, genetically at risk of CD, dermati-

tis herpetiformis, gluten, gluten ataxia, gluten intolerance, gluten sensitivity and gliadin-specific antibodies.

Results CD was defined as 'a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically predisposed individuals'. Classical CD was defined as 'CD presenting with signs and symptoms of malabsorption. Diarrhoea, steatorrhoea, weight loss or growth failure is required.' 'Gluten-related disorders' is the suggested umbrella term for all diseases triggered by gluten and the term gluten intolerance should not to be used. Other definitions are presented in the paper.

Conclusion This paper presents the Oslo definitions for CD-related terms.

Keywords: gluten-free diet; t-cell lymphoma; irritable-bowel-syndrome; iron-deficiency anemia; deamidated gliadin peptides; dependent diabetes-mellitus; small-intestinal mucosa; dermatitis-herpetiformis; intraepithelial lymphocytes; tissue transglutaminase

来源出版物: Gut , 2013, 62(1): 43-52联系邮箱: Leffler, DA; dleffler@caregroup.harvard.edu

被引频次: 89

Helicobacter pylori resistance to antibiotics in Europe and its relationship to antibiotic consumption

Megraud, F; Coenen, S; Versporten, A; et al.

Abstract: Objective Resistance to antibiotics is the major cause of treatment failure of Helicobacter pylori infection. A study was conducted to assess prospectively the antibacterial resistance rates of H pylori in Europe and to study the link between outpatient antibiotic use and resistance levels in different countries.

Design Primary antibiotic resistance rates of H pylori were determined from April 2008 to June 2009 in 18 European countries. Data on yearly and cumulative use over several years of systemic antibacterial agents in ambulatory care for the period 2001-8 were expressed in Defined Daily Doses(DDD)per 1000 inhabitants per day. The fit of models and the degree of ecological association between antibiotic use and resistance data were assessed using generalised linear mixed models.

Results Of 2204 patients included, H pylori resistance rates for adults were 17.5% for clarithromycin, 14.1% for levofloxacin and 34.9% for metronidazole, and were significantly higher for clarithromycin and levofloxacin in Western/Central and Southern Europe(>20%)than in Northern European countries(<10%). Model fit improved for each additional year of antibiotic use accumulated, but the best fit was obtained for 2005. A significant association was found between outpatient quinolone use and the proportion of levofloxacin resistance(p = 0.0013)and between the use of long-acting macrolides only and clarithromycin resistance(p = 0.036).

Conclusion In many countries the high rate of clarithromycin resistance no longer allows its empirical use in standard anti-H pylori regimens. The knowledge of outpatient antibiotic consumption may provide a simple tool to predict the susceptibility of H pylori to quinolones and to macrolides and to adapt the treatment strategies.

Keywords: outpatient quinolone use; prospective multicenter; triple therapies; consensus report; surveillance; infection; efficacy; esac;azithromycin; management

来源出版物: Gut , 2013, 62(1): 34-42联系邮箱: Megraud, F; francis.megraud@chu-bordeaux.fr

GENETICS HEREDITY 遗传学与遗传

被引频次: 400

MEGA6: Molecular Evolutionary Genetics Analysis Version 6.0

Tamura, K; Stecher, G; Peterson, D; et al.

Abstract: We announce the release of an advanced version of the Molecular Evolutionary Genetics Analysis(MEGA)software, which currently contains facilities for building sequence alignments, inferring phylogenetic histories, and conducting molecular evolutionary analysis. In version 6.0, MEGA now enables the inference of timetrees, as it implements the RelTime method for estimating divergence times for all branching points in a phylogeny. A new Timetree Wizard in MEGA6 facilitates this timetree inference by providing a graphical user interface(GUI)to specify the phylogeny and calibration constraints step-by-step. This version also contains enhanced algorithms to search for the optimal trees under evolutionary criteria and implements a more advanced memory management that can double the size of sequence data sets to which MEGA can be applied. Both GUI and command-line versions of MEGA6 can be downloaded from www.megasoftware.net free of charge.

来源出版物: Molecular Biology and Evolution , 2013, 30(12): 2725-2729联系邮箱: Kumar, S; s.kumar@asu.edu

被引频次: 370

MAFFT Multiple Sequence Alignment Software Version 7: Improvements in Performance and Usability

Katoh, K; Standley, DM

Abstract: We report a major update of the MAFFT multiple sequence alignment program. This version has several new features, including options for adding unaligned sequences into an existing alignment, adjustment of direction in nucleotide alignment, constrained alignmentand parallel processing, which were implemented after the previous major update. This report shows actual examples to explain how these features work, alone and in combination. Some examples incorrectly aligned by MAFFT are also shown to clarify its limitations. We discuss how to avoid misalignments, and our ongoing efforts to overcome such limitations.

Keywords: protein sequences; unaligned sequences; rna sequences; database; tree; algorithm; accuracy; clustal; information; sensitivity

来源出版物: Molecular Biology and Evolution , 2013, 30(4): 772-780联系邮箱: Katoh, K; kazutaka.katoh@aist.go.jp

被引频次: 127

TopHat2: accurate alignment of transcriptomes in the presence of insertions, deletions and gene fusions

Kim, D; Pertea, G; Trapnell, C; et al.

Abstract: TopHat is a popular spliced aligner for RNA-sequence(RNA-seq)experiments. In this paper, we describe TopHat2, which incorporates many significant enhancements to TopHat. TopHat2 can align reads of various lengths produced by the latest sequencing technologies, while allowing for variable-length indels with respect to the reference genome. In addition to de novo spliced alignment, TopHat2 can align reads across fusion breaks, which can occur after genomic translocations. TopHat2 combines the ability to identify novel splice sites with direct mapping to known transcripts, producing sensitive and accurate alignments, even for highly repetitive genomes or in the presence of pseudogenes. TopHat2 is available at http://ccb.jhu.edu/software/tophat.

Keywords: rna-seq; human genome; pseudogenes; discovery; ultrafast; reads

来源出版物: Genome Biology , 2013, 14(4): R36联系邮箱: Kim, D; infphilo@umiacs.umd.edu

被引频次: 208

ACMG recommendations for reporting of incidental findings in clinical exome and genome sequencing

Green, RC; Berg, JS; Grody, WW; et al.

Abstract: In clinical exome and genome sequencing, there is a potential for the recognition and reporting of incidental or secondary findings unrelated to the indication for ordering the sequencing but of medical value for patient care. The American College of Medical Genetics and Genomics(ACMG)recently published a policy statement on clinical sequencing that emphasized the importance of alerting the patient to the possibility of such results in pretest patient discussions, clinical testing, and reporting of results. The ACMG appointed a Working Group on Incidental Findings in Clinical Exome and Genome Sequencing to make recommendations about responsible management of incidental findings when patients undergo exome or genome sequencing. This Working Group conducted a year-long consensus process, including an open forum at the 2012 Annual Meeting and review by outside experts, and produced recommendations that have been approved by the ACMG Board. Specific and detailed recommendations, and the background and rationale for these recommendations,are described herein. The ACMG recommends that laboratories performing clinical sequencing seek and report mutations of the specified classes or types in the genes listed here. This evaluation and reporting should be performed for all clinical germline(constitutional)exome and genome sequencing, including the "normal" of tumor-normal subtractive analyses in all subjects, irrespective of age but excluding fetal samples. We recognize that there are insufficient data on penetrance and clinical utility to fully support these recommendations, and we encourage the creation of an ongoing process for updating these recommendations at least annually as further data are collected.

Keywords: medicine; return; perspectives; genetics; children; future; policy

来源出版物: Genetics in Medicine , 2013, 15(7): 565-574联系邮箱: Green, RC; rcgreen@genetics.med.harvard.edu

被引频次: 150

Hybridization and speciation

Abbott, R; Albach, D; Ansell, S; et al.

Abstract: Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow and recombination. It may accelerate speciation via adaptive introgression or cause near-instantaneous speciation by allopolyploidization. It may have multiple effects at different stages and in different spatial contexts within a single speciation event. We offer a perspective on the context and evolutionary significance of hybridization during speciation, highlighting issues of current interest and debate. In secondary contact zones, it is uncertain if barriers to gene flow will be strengthened or broken down due to recombination and gene flow. Theory and empirical evidence suggest the latter is more likely, except within and around strongly selected genomic regions. Hybridization may contribute to speciation through the formation of new hybrid taxa, whereas introgression of a few loci may promote adaptive divergence and so facilitate speciation. Gene regulatory networks, epigenetic effects and the evolution of selfish genetic material in the genome suggest that the DobzhanskyMuller model of hybrid incompatibilities requires a broader interpretation. Finally, although the incidence of reinforcement remains uncertain, this and other interactions in areas of sympatry may have knock-on effects on speciation both within and outside regions of hybridization.

Keywords: homoploid hybrid speciation; reproductive character displacement; adaptive population divergence; senecio-squalidus asteraceae; adjacent plant-populations; gene-expression divergence; natural-selection; local adaptation; sexual selection; genome duplication

来源出版物: Journal of Evolutionary Biology , 2013, 26(2): 229-246联系邮箱: Butlin, RK; r.k.butlin@sheffield.ac.uk

GEOCHEMISTRY GEOPHYSICS 地球化学与地球物理

被引频次: 173

INTCAL13 AND MARINE13 RADIOCARBON AGE CALIBRATION CURVES 0-50,000 YEARS CAL BP

Reimer, PJ; Bard, E; Bayliss, A; et al.

Abstract: The IntCal09 and Marine09 radiocarbon calibration curves have been revised utilizing newly available and updated data sets from C-14 measurements on tree rings, plant macrofossils, speleothems, corals, and foraminifera. The calibration curves were derived from the data using the random walk model(RWM)used to generate IntCal09 and Marine09, which has been revised to account for additional uncertainties and error structures. The new curves were ratified at the 21st International Radiocarbon conference in July 2012 and are available as Supplemental Material at www.radiocarbon.org. The database can be accessed at http://intcal.qub.ac.uk/intcal13/.

Keywords: late-glacial chronology; c-14 calibration; lake suigetsu; younger dryas; reservoir ages; tree-rings; kyr bp; planktonicforaminifera; last deglaciation; field intensity

来源出版物: Radiocarbon , 2013, 55(4): 1869-1887联系邮箱: Reimer, PJ; p.j.reimer@qub.ac.uk

被引频次: 95

The organic geochemistry of glycerol dialkyl glycerol tetraether lipids: A review

Schouten, S; Hopmans, EC; Damste, JSS

Abstract: Glycerol dialkyl glycerol tetraether(GDGT)lipids are membrane lipids which were long thought to be synthesized mainly by archaea, organisms thought to be limited to extreme environments. Analysis of environmental samples over the last decade has shown,however, that their structural diversity and sources are much wider than anticipated and that they occur ubiquitously in a wide range of environments, such as oceans and lakes, and their(sub)surface sediments, as well as soils. Several GDGTs have been unambiguously identified and can be used as biomarker lipids, since they are preserved in immature sediments < 140 Ma. Close examination of the distributions has led to the discovery that GDGTs might be used as proxies for certain environmental parameters, such as the input of soil organic matter to marine environments, soil pH, air temperature and sea and lake water temperature. Here, we review the progress made over the last decade in the analysis, occurrence and recognition of sources of GDGTs, their applications as biomarker lipids, and the development and application of proxies based on their distributions.

Keywords: ammonia-oxidizing archaea; ionization-mass-spectrometry; sea-surface temperatures; eocene thermal maximum; intact polar lipids; performance liquid-chromatography; carbon isotopic compositions; anaerobic methane oxidation; terrestrial hot-springs; sequential chemical degradation

来源出版物: Organic Geochemistry , 2013, 54: 19-61联系邮箱: Schouten, S; stefan.schouten@nioz.nl

被引频次: 45

Preliminary result for rupture process of Apr. 20, 2013, Lushan Earthquake, Sichuan, China

Wang, WM; Hao, JL; Yao, ZX

Abstract: The rupture process of the 20, Apr. 2013, Lushan earthquake was fast estimated by finite fault model method using far field body waveform records. The predicted shakemap is subsequently calculated based on rupture fault model of this earthquake. Results show that the earthquake is an M(w)6.7 thrusting event which occurred on the south part of Longmen Shan fault zone with 159 cm largest slip. By the predicted shakemap, the intensity of epicenter region should reached VIII-IX on Chinese seismic intensity scale. The thrusting mechanism of Lushan earthquake is similar to that of Wenchuan earthquake. The earthquake rupture of this event occurred on the southern section of Longmen Shan fault where shows increase of Coulomb stress caused by the Wenchuan earthquake. This event may be triggered by the Wenchuan earthquake. On the view of macroscopic, this earthquake can be considered as an delayed strong aftershock of Wenchuan earthquake.

Keywords: wenchuan earthquake; stress changes; faults

来源出版物: Chinese Journal of Geophysics-chinese Edition , 2013, 56(4): 1412-1417联系邮箱: Wang, WM; wangwm@itpcas.ac.cn

被引频次: 38

Aegean tectonics: Strain localisation, slab tearing and trench retreat

Jolivet, L; Faccenna, C; Huet, B; et al.

Abstract: We review the geodynamic evolution of the Aegean-Anatolia region and discuss strain localisation there over geological times. From Late Eocene to Present, crustal deformation in the Aegean backarc has localised progressively during slab retreat. Extension started with the formation of the Rhodope Metamorphic Core Complex(Eocene)and migrated to the Cyclades and the northern Menderes Massif(Oligocene and Miocene), accommodated by crustal-scale detachments and a first series of core complexes(MCCs). Extension then localised in Western Turkey, the Corinth Rift and the external Hellenic arc after Messinian times, while the North Anatolian Fault penetrated the Aegean Sea. Through time the direction and style of extension have not changed significantly except in terms of localisation. The contributions of progressive slab retreat and tearing, basal drag, extrusion tectonics and tectonic inheritance are discussed and we favour a model(1)where slab retreat is the main driving engine,(2)successive slab tearing episodes are the main causes of this stepwise strain localisation and(3)the inherited heterogeneity of the crust is a major factor for localising detachments. The continental crust has an inherited strong heterogeneity and crustal-scale contacts such as major thrust planes act as weak zones or as zones of contrast of resistance and viscosity that can localise later deformation. The dynamics of slabs at depth and the asthenospheric flow due to slab retreat also have influence strain localisation in the upper plate. Successive slab ruptures from the Middle Miocene to the late Miocene have isolated a narrow strip of lithosphere, still attached to the African lithosphere below Crete. The formation of the North Anatolian Fault is partly a consequence of this evolution. The extrusion of Anatolia and the Aegean extension are partly driven from below(asthenospheric flow)and from above(extrusion of a lid of rigid crust).

Keywords: southern menderes massif; metamorphic core complex; high-pressure metamorphism; north-anatolian fault; hellenic subduction zone; seismic anisotropy beneath; cycladic blueschist belt; travel-time tomography; alpine-himalayan belt; mesozoic cover series

来源出版物: Tectonophysics , 2013, 597: 1-33联系邮箱: Jolivet, L; laurent.jolivet@univ-orleans.fr

被引频次: 38

Rupture process of the Lushan 4.20 earthquake and preliminary analysis on the disaster-causing mechanism

Zhang, Y; Xu, LS; Chen, YT

Abstract: Fast inversion for the rupturing process of the 20 April 2013 Lushan, Ya'an earthquake was conducted about 3 hours after the earthquake occurrence by using the GSN teleseismic waveform data. The obtained moment magnitude is M(w)6.8. It included two sub-events during the rupturing process, which occurred near the hypocenter or rupture initiation point and did not show significant rupture direction. The rupture of the earthquake did not break through the ground surface, and seismic disaster is concentrated on the hanging wall of the fault, around Lushan county and Baoxing county of Sichuan Province.

来源出版物: Chinese Journal of Geophysics-chinese Edition , 2013, 56(4): 1408-1411联系邮箱: Zhang, Y; chenyt@cea-igp.ac.cn

GEOGRAPHY PHYSICAL 自然地理学

被引频次: 114

Bedmap2: improved ice bed, surface and thickness datasets for Antarctica

Fretwell, P; Pritchard, HD; Vaughan, DG; et al.

Abstract: We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60 degrees S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation(Bedmap1)in 2001. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1. In most parts of Antarctica the subglacial landscape is visible in much greater detail than was previously available and the improved data-coverage has in many areas revealed the full scale of mountain ranges, valleys, basins and troughs, only fragments of which were previously indicated in local surveys. The derived statistics for Bedmap2 show that the volume of ice contained in the Antarctic ice sheet(27 million km3)and its potential contribution to sea-level rise(58 m)are similar to those of Bedmap1, but the mean thickness of the ice sheet is 4.6% greater, the mean depth of the bed beneath the grounded ice sheet is 72 m lower and the area of ice sheet grounded on bed below sea level is increased by 10 %. The Bedmap2 compilation highlights several areas beneath the ice sheet where the bed elevation is substantially lower than the deepest bed indicated by Bedmap1. These products, along with grids of data coverage and uncertainty, provide new opportunities for detailed modelling of the past and future evolution of the Antarctic ice sheets.

Keywords: digital elevation model; satellite radar; east antarctica; west antarctica; sheet; stream; sea; altimetry; gravity; bathymetry

来源出版物: Cryosphere , 2013, 7(1): 375-393联系邮箱: Fretwell, P; ptf@bas.ac.uk

被引频次: 44

A new bed elevation dataset for Greenland

Bamber, JL; Griggs, JA; Hurkmans, RTWL; et al.

Abstract: We present a new bed elevation dataset for Greenland derived from a combination of multiple airborne ice thickness surveys undertaken between the 1970s and 2012. Around 420000 line kilometres of airborne data were used, with roughly 70% of this having been collected since the year 2000, when the last comprehensive compilation was undertaken. The airborne data were combined with satellite-derived elevations for non-glaciated terrain to produce a consistent bed digital elevation model(DEM)over the entire island includingacross the glaciated-ice free boundary. The DEM was extended to the continental margin with the aid of bathymetric data, primarily from a compilation for the Arctic. Ice thickness was determined where an ice shelf exists from a combination of surface elevation and radar soundings. The across-track spacing between flight lines warranted interpolation at 1 km postings for significant sectors of the ice sheet. Grids of ice surface elevation, error estimates for the DEM, ice thickness and data sampling density were also produced alongside a mask of land/ocean/grounded ice/floating ice. Errors in bed elevation range from a minimum of +/- 10 m to about +/- 300 m, as a function of distance from an observation and local topographic variability. A comparison with the compilation published in 2001 highlights the improvement in resolution afforded by the new datasets, particularly along the ice sheet margin, where ice velocity is highest and changes in ice dynamics most marked. We estimate that the volume of ice included in our land-ice mask would raise mean sea level by 7.36 m, excluding any solid earth effects that would take place during ice sheet decay.

Keywords: ice-sheet; shelf; thickness; glacier; model; flow

来源出版物: Cryosphere , 2013, 7(2): 499-510联系邮箱: Bamber, JL; j.bamber@bristol.ac.uk

被引频次: 37

Quantitative reconstructions in palaeolimnology: new paradigm or sick science?

Juggins, S

Abstract: Quantitative reconstructions from biological proxies have revolutionised palaeolimnology but the methodology is not without problems. The most important of these result from attempts to reconstruct non-causal environmental variables and from the effects of secondary variables. Non-causal variables act as surrogates for often unknown or unquantified ecological factors and the method assumes that these relationships are invariant in space and time. This assumption is almost never met and examples of diatom models for water depth and summer temperature demonstrate how violation leads to spurious and misleading reconstructions. In addition, comparison of published species optima indicate that a number of models have little or no predictive power outside their current spatial setting. Finally, experiments using simulated training sets of known properties demonstrate how changes in secondary "nuisance" variables can lead to large, consistent,and interpretable trends in a reconstruction that are completely spurious and independent of any real change in the reconstructed variable. These problems pervade many quantitative reconstructions in palaeolimnology and other disciplines. Palaeoecologists must give greater attention to what can and cannot be reconstructed and explicitly address the dangers of reconstructing surrogate and confounded variables if our reconstructions are to remain credible.

Keywords: sedimentary diatom assemblages; fresh-water diatoms; past environmental-conditions; chrysophyte cyst assemblages; gaussian response model; inference models; northern sweden; lake-sediments; air-temperature; canada lakes

来源出版物: Quaternary Science Reviews , 2013, 64: 20-32联系邮箱: Juggins, S; Stephen.juggins@ncl.ac.uk

被引频次: 33

Topographic structure from motion: a new development in photogrammetric measurement

Fonstad, MA; Dietrich, JT; Courville, BC; et al.

Abstract: The production of topographic datasets is of increasing interest and application throughout the geomorphic sciences, and river science is no exception. Consequently, a wide range of topographic measurement methods have evolved. Despite the range of available methods, the production of high resolution, high quality digital elevation models(DEMs)requires a significant investment in personnel time, hardware and/or software. However, image-based methods such as digital photogrammetry have been decreasing in costs. Developed for the purpose of rapid, inexpensive and easy three-dimensional surveys of buildings or small objects, the structure from motion' photogrammetric approach(SfM)is an image-based method which could deliver a methodological leap if transferred to geomorphic applications,requires little training and is extremely inexpensive. Using an online SfM program, we created high-resolution digital elevation models of a river environment from ordinary photographs produced from a workflow that takes advantage of free and open source software. This process reconstructs real world scenes from SfM algorithms based on the derived positions of the photographs in three-dimensional space. The basic product of the SfM process is a point cloud of identifiable features present in the input photographs. This point cloud can be georeferenced from a small number of ground control points collected in the field or from measurements of camera positions at the time of image acquisition. The georeferenced point cloud can then be used to create a variety of digital elevation products. We examine the applicability of SfM in the Pedernales River in Texas(USA), where several hundred images taken from a hand-held helikite are used to produce DEMs of the fluvial topographic environment. This test shows that SfM and low-altitude platforms can produce point clouds with point densities comparable with airborne LiDAR, with horizontal and vertical precision in the centimeter range, and with very low capital and labor costs and low expertise levels.

Keywords: automated digital photogrammetry; unmanned aerial vehicle; gravel-bed rivers; fluvial geomorphology; photo collections; riparian forest; high-resolution; image-analysis; photography; generation

来源出版物: Earth Surface Processes and Landforms , 2013, 38(4): 421-430联系邮箱: Fonstad, MA; fonstad@uoregon.edu

被引频次: 32

Selecting thresholds for the prediction of species occurrence with presence-only data

Liu, CR; White, M; Newell, G

Abstract: Aim Species distribution models have been widely used to tackle ecological, evolutionary and conservation problems. Most species distribution modelling techniques produce continuous suitability predictions, but many real applications(e.g. reserve design, species invasion and climate change impact assessment)and model evaluations require binary outputs, and thresholds are needed for these transformations. Although there are many threshold selection methods for presence/absence data, it is unclear whether these are suitable for presence-only data. In this paper, we investigate mathematically and empirically which of the existing threshold selection methods can be used confidently with presence-only data. Location We used real spatially explicit environmental data derived from the western part of the state of Victoria, south-eastern Australia, and simulated species distributions within this area. Methods Thirteen existing threshold selection methods were investigated mathematically to see whether the same threshold can be produced using either presence/absence data or presence-only data. We further adopted a simulation approach, created many virtual species with differing prevalences in a real landscape in south-eastern Australia, generated data sets with different proportions of pseudo-absences, built eight types of models with four modelling techniques, and investigated the behaviours of four threshold selection methods in these situations. Results Three threshold selection methods were not affected by pseudo-absences, including max SSS(which is based on maximizing the sum of sensitivity and specificity), the prevalence of model training data and the mean predicted value of a set of random points. Max SSS produced higher sensitivity in most cases and higher true skill statistic and kappa in many cases than the other methods. The other methods produced different thresholds from presence-only data to those determined from presence/absence data. Main conclusions Max SSS is a promising method for threshold selection when only presence data are available.

Keywords: distribution models; sample-size; presence-absence; distributions; performance; accuracy; conservation; biodiversity; niche;bias

来源出版物: Journal of Biogeography , 2013, 40(4): 778-789联系邮箱: Liu, CR; canran.liu@dse.vic.gov.au

GEOGRAPHY 地理学

被引频次: 31

Affluence drives the global displacement of land use

Weinzettel, J; Hertwich, EG; Peters, GP; et al.

Abstract: Increasing affluence is often postulated as a main driver for the human footprint on biologically productive areas, identified among the main causes of biodiversity loss, but causal relationships are obscured by international trade. Here, we trace the use of land and ocean area through international supply chains to final consumption, modeling agricultural, food, and forestry products on a high level of resolution while also including the land requirements of manufactured goods and services. In 2004, high-income countries required more biologically productive land per capita than low-income countries, but this connection could only be identified when land used to produce internationally traded products was taken into account, because higher-income countries tend to displace a larger fraction of land use. The equivalent land and ocean area footprint of nations increased by a third for each doubling of income, with all variables analyzed on a per capita basis. This increase came largely from imports, which increased proportionally to income. Export depended mostly on the capacity of countries to produce useful biomass, the biocapacity. Our analysis clearly shows that countries with a high biocapacity per capita tend to spare more land for nature. Biocapacity per capita can be increased through more intensive production or by reducing population density. The net displacement of land use from high-income to low-income countries amounted to 6% of the global land demand, even though high-income countries had more land available per capita than low-income countries. In particular, Europe and Japan placed high pressure on ecosystems in lower-income countries.

Keywords: international-trade; food; growth; intensification; consequences; environment; population; footprint

来源出版物: Global Environmental Change-human and Policy Dimensions , 2013, 23(2): 433-438

联系邮箱: Hertwich, EG; edgar.hertwich@ntnu.no

被引频次: 28

Dynamic adaptive policy pathways: A method for crafting robust decisions for a deeply uncertain world

Haasnoot, M; Kwakkel, JH; Walker, WE; et al.

Abstract: A new paradigm for planning under conditions of deep uncertainty has emerged in the literature. According to this paradigm, a planner should create a strategic vision of the future, commit to short-term actions, and establish a framework to guide future actions. A plan that embodies these ideas allows for its dynamic adaptation over time to meet changing circumstances. We propose a method for decisionmaking under uncertain global and regional changes called 'Dynamic Adaptive Policy Pathways'. We base our approach on two complementary approaches for designing adaptive plans: 'Adaptive Policymaking' and 'Adaptation Pathways'. Adaptive Policymaking is atheoretical approach describing a planning process with different types of actions(e.g. 'mitigating actions' and 'hedging actions')and signposts to monitor to see if adaptation is needed. In contrast, Adaptation Pathways provides an analytical approach for exploring and sequencing a set of possible actions based on alternative external developments over time. We illustrate the Dynamic Adaptive Policy Pathways approach by producing an adaptive plan for long-term water management of the Rhine Delta in the Netherlands that takes into account the deep uncertainties about the future arising from social, political, technological, economic, and climate changes. The results suggest that it is worthwhile to further test and use the approach.

Keywords: climate-change; water management; infrastructure; adaptation; netherlands; transition; scenarios; medicine; future

来源出版物: Global Environmental Change-human and Policy Dimensions , 2013, 23(2): 485-498

联系邮箱: Haasnoot, M; Marjolijn.Haasnoot@deltares.nl

被引频次: 19

Do people "personally experience" global warming, and if so how, and does it matter?

Akerlof, K; Maibach, EW; Fitzgerald, D; et al.

Abstract: For most people, the direct and personally observable signals of climate change should be difficult to detect amid the variability of everyday weather. Yet, previous research has shown that some people believe they have personally experienced global warming. Through four related studies, our paper sheds light on what signals of global warming some people believe they are detecting, why, and whether or not it matters. These studies were conducted using population survey and climatic data from a single county in Michigan. Study 1 found that 27% of the county's adult residents felt that they had personally experienced global warming. Study 2 - based on content analysis of people's open-ended responses - found that the most frequently described personal experiences of global warming were changes in seasons(36%), weather(25%), lake levels(24%), animals and plants(20%), and snowfall(19%). Study 3 - based on NOAA climatic data -found that most, but not all, of these detected signals are borne out in the climatic record. Study 4 - using the survey data - found that personal experience of global warming matters in that it predicts perceptions of local risk of global warming, controlling for demographics,political affiliation, and cultural beliefs about national policy outcomes. We conclude that perceived personal experience of global warming appears to heighten people's perception of the risks, likely through some combination of direct experience, vicarious experience(e.g., news media stories), and social construction.

Keywords: lake-effect snowfall; climate-change; place attachment; perceptions; risk; consequences; rationality; temperature; feelings;debate

来源出版物: Global Environmental Change-human and Policy Dimensions , 2013, 23(1): 81-91

联系邮箱: Akerlof, K; kakerlof@gmu.edu

被引频次: 18

Global river discharge and water temperature under climate change

van Vliet, MTH; Franssen, WHP; Yearsley, JR; et al.

Abstract: Climate change will affect hydrologic and thermal regimes of rivers, having a direct impact on freshwater ecosystems and human water use. Here we assess the impact of climate change on global river flows and river water temperatures, and identify regions that might become more critical for freshwater ecosystems and water use sectors. We used a global physically based hydrological-water temperature modelling framework forced with an ensemble of bias-corrected general circulation model(GCM)output for both the SRES A2 and B1 emissions scenario. This resulted in global projections of daily river discharge and water temperature under future climate. Our results show an increase in the seasonality of river discharge(both increase in high flow and decrease in low flow)for about one-third of the global land surface area for 2071-2100 relative to 1971-2000. Global mean and high(95th percentile)river water temperatures are projected to increase on average by 0.8-1.6(1.0-2.2)degrees C for the SRES B1-A2 scenario for 2071-2100 relative to 1971-2000. The largest water temperature increases are projected for the United States, Europe, eastern China, and parts of southern Africa and Australia. In these regions, the sensitivities are exacerbated by projected decreases in low flows(resulting in a reduced thermal capacity). For strongly seasonal rivers with highest water temperatures during the low flow period, up to 26% of the increases in high(95th percentile)water temperature can be attributed indirectly to low flow changes, and the largest fraction is attributable directly to increased atmospheric energy input. A combination of large increases in river temperature and decreases in low flows are projected for the southeastern United States, Europe,eastern China, southern Africa and southern Australia. These regions could potentially be affected by increased deterioration of water quality and freshwater habitats, and reduced water available for human uses such as thermoelectric power and drinking water production.

Keywords: stream temperature; united-states; surface-water; change impact; potential impacts; ocean circulation; air temperatures; low flows; model; quality

来源出版物: Global Environmental Change-human and Policy Dimensions , 2013, 23(2): 450-464

联系邮箱: van Vliet, MTH; michelle.vanvliet@wur.nl

被引频次: 17

A survey of urban climate change experiments in 100 cities

Broto, VC; Bulkeley, H

Abstract: Cities are key sites where climate change is being addressed. Previous research has largely overlooked the multiplicity of climate change responses emerging outside formal contexts of decision-making and led by actors other than municipal governments. Moreover,existing research has largely focused on case studies of climate change mitigation in developed economies. The objective of this paper is to uncover the heterogeneous mix of actors, settings, governance arrangements and technologies involved in the governance of climate change in cities in different parts of the world.

The paper focuses on urban climate change governance as a process of experimentation. Climate change experiments are presented here as interventions to try out new ideas and methods in the context of future uncertainties. They serve to understand how interventions work in practice, in new contexts where they are thought of as innovative. To study experimentation, the paper presents evidence from the analysis of a database of 627 urban climate change experiments in a sample of 100 global cities.

The analysis suggests that, since 2005, experimentation is a feature of urban responses to climate change across different world regions and multiple sectors. Although experimentation does not appear to be related to particular kinds of urban economic and social conditions, some of its core features are visible. For example, experimentation tends to focus on energy. Also, both social and technical forms of experimentation are visible, but technical experimentation is more common in urban infrastructure systems. While municipal governments have a critical role in climate change experimentation; they often act alongside other actors and in a variety of forms of partnership. These findings point at experimentation as a key tool to open up new political spaces for governing climate change in the city.

Keywords: greenhouse-gas emissions; london congestion charge; local commitment; change impacts; vulnerability; adaptation; policy;resilience; protection; management

来源出版物: Global Environmental Change-human and Policy Dimensions , 2013, 23(1): 92-102

联系邮箱: Broto, VC; v.castanbroto@ucl.ac.uk

GEOLOGY 地质学

被引频次: 33

Potentially induced earthquakes in Oklahoma, USA: Links between wastewater injection and the 2011 M-w 5.7 earthquake sequence

Keranen, KM; Savage, HM; Abers, GA; et al.

Abstract: Significant earthquakes are increasingly occurring within the continental interior of the United States, including five of moment magnitude(M-w)≥5.0 in 2011 alone. Concurrently, the volume of fluid injected into the subsurface related to the production of unconventional resources continues to rise. Here we identify the largest earthquake potentially related to injection, an M-w 5.7 earthquake in November 2011 in Oklahoma. The earthquake was felt in at least 17 states and caused damage in the epicentral region. It occurred in a sequence, with 2 earthquakes of M-w 5.0 and a prolific sequence of aftershocks. We use the aftershocks to illuminate the faults that ruptured in the sequence, and show that the tip of the initial rupture plane is within similar to 200 m of active injection wells and within similar to 1 km of the surface; 30% of early aftershocks occur within the sedimentary section. Subsurface data indicate that fluid was injected into effectively sealed compartments, and we interpret that a net fluid volume increase after 18 yr of injection lowered effective stress on reservoir-bounding faults. Significantly, this case indicates that decades-long lags between the commencement of fluid injection and the onset of induced earthquakes are possible, and modifies our common criteria for fluid-induced events. The progressive rupture of three fault planes in this sequence suggests that stress changes from the initial rupture triggered the successive earthquakes, including one larger than the first.

Keywords: denver earthquakes; deformation; pressure; fluid

来源出版物: Geology , 2013, 41(6): 699-702

被引频次: 22

Retrodeforming the Arabia-Eurasia collision zone: Age of collision versus magnitude of continental subduction

McQuarrie, N; van Hinsbergen, DJJ

Abstract: The Arabia-Eurasia collision has been linked to global cooling, the slowing of Africa, Mediterranean extension, the rifting of the Red Sea, an increase in exhumation and sedimentation on the Eurasian plate, and the slowing and deformation of the Arabian plate. Collision age estimates range from the Late Cretaceous to Pliocene, with most estimates between 35 and 20 Ma. We assess the consequences of these collision ages on the magnitude and location of continental consumption by compiling all documented shortening within the region,and integrating this with plate kinematic reconstructions. Shortening estimates across the orogen allow for similar to 350 km of Neogene upper crustal contraction, necessitating collision by 20 Ma. A 35 Ma collision requires additional subduction of similar to 400-600 km of Arabian continental crust. Using the Oman ophiolite as an analogue, ophiolitic fragments preserved along the Zagros suture zone permitsimilar to 180 km of subduction of the Arabian continental margin plus overlying ophiolites. Wholesale subduction of this more dense continental margin plus ophiolites would reconstruct similar to 400-500 km of postcollisional Arabia-Eurasia convergence, consistent with a ca. 27 Ma initial collision age. This younger Arabia-Eurasia collision suggests a noncollisional mechanism for the slowing of Africa, and associated extension.

Keywords: fold-thrust belt; foreland-basin; cenozoic evolution; tectonic evolution; alborz mountains; northern iran; zagros; deformation;constraints; convergence

来源出版物: Geology , 2013, 41(3): 315-318

被引频次: 22

The development of continental collision metallogeny and its application.

Chen, YJ

Abstract: The importance of the continental collision metallogeny is addressed in this paper. The development history of the continental collision metallogeny is divided into five periods, namely, preparation(before 1970), incubation(1971 similar to 1990), birth(1991 similar to 2000), growth(2001 similar to 2010)and maturation(2011 and thereafter). The hardcore of the continental collision metallogeny is considered to include four tectonic models for Collisional orogeny, Metallogeny and Fluid flow(abbreviated to CMF)at differing scales(global tectonics, orogen, terrane and deposit). It also contains the characterizations of four classes of hydrothermal mineral systems formed in continental collision regime as well as their comparative illustrations with the mineral systems formed in other tectonic settings. The paper also introduces several successful ore-exploration examples guided by the continental collision metallogeny. The facts presented in the paper show that Chinese geologists have contributed much to the development of the continental collision metallogeny, by utilizing the unique conditions of abundant continental collision orogens in China.

Keywords: yangshan gold deposit; porphyry mo deposit; ore-forming fluids; tieluping silver deposit; henan province; isotope geochemistry;qinling orogen; gansu province; north china; inclusion geochemistry

来源出版物: Acta Petrologica Sinica , 2013, 29(1): 1-17联系邮箱: Chen, YJ; yjchen@pku.edu.cn

被引频次: 21

Solidus of alkaline carbonatite in the deep mantle

Litasov, KD; Shatskiy, A; Ohtani, E; et al.

Abstract: Minor amounts of alkalies(Na and K)can reduce drastically the solidus temperatures of carbonated silicate mantle, by as much as 400-500 degrees C. Low-degree melting of carbonated peridotite and eclogite at pressures of 3-10 GPa produces Na- and K-bearing carbonatite melt. Mass-balance calculations of samples obtained below apparent solidi show clear deficits of alkalies, suggesting the presence of minor alkali-rich liquid or solid carbonate phases. Here we determine the true solidi in Na- and K-bearing carbonate systems and report the stability of alkaline carbonate phases. Melting of subducting alkaline carbonates would likely occur at transition zone depths to produce mobile carbonatite melt diapirs that migrate upward, modifying and oxidizing the upper mantle and initiating volcanism at the surface.

Keywords: transition zone; phase-relations; earths mantle; melt compositions; bearing eclogite; gpa; peridotite; metasomatism; lithosphere;diamond

来源出版物: Geology , 2013, 41(1): 79-82

被引频次: 19

Spatio-temporal distribution and tectonic settings of the major iron deposits in China: An overview

Zhang, ZC; Hou, T; Santosh, M; et al.

Abstract: China has a rich reserve of iron ores and hosts most of the major types of iron deposits recognized worldwide. However, among these, the banded iron formation(BIF), skarn, apatite-magnetite, volcanic-hosted, sedimentary hematite and magmatic Ti-Fe-(V)deposits constitute the most economically important types. High-grade iron ores(>50% Fe)are relatively rare, and are mostly represented by the skarn-type. Most of the BIF deposits formed in the Neoarchean, with a peak at similar to 2.5 Ga, and are mainly distributed in the North China Craton. The majority of these is associated with volcanic rocks, and therefore belongs to the Algoma-type. The superior-type BIF deposits formed during the Paleoproterozoic occur subordinately(ca. 25%), and are related mainly to rifts(or passive continental margins). In addition, minor Superior-type BIF deposits have also been recognized. The skarn iron deposits are widely distributed in China, especially in the uplifted areas of eastern China, and form several large iron ore clusters. These ore deposits are genetically associated with intermediate, intermediate-felsic and felsic intrusions with a peak age of formation at ca. 130 Ma. They display common characteristics including alteration and nature of mineralization. The apatite-magnetite deposits occurring in the Ningwu and Luzong Cretaceous terrigenous volcanic basins along the Middle-Lower Yangtze River Valley, are spatially and temporally associated with dioritic subvolcanic intrusions. The ores in this type are characterized by magnetite and apatite. The volcanic-hosted iron deposits are associated with submarine volcan-ic-sedimentary sequences, and are widely distributed in the orogenic belts of western China, including Western Tianshan, Eastern Tianshan,Beishan, Altay, Kaladawan area in the eastern part of the Altyn Tagh Mountain and southwestern margin of South China Block. These deposits show a considerable age range, from Proterozoic to Mesozoic, but with more than 70% were formed in the Paleozoic, especially during the Late Paleozoic. The metallogenesis in these deposits can be correlated to the space-time evolution of the submarine volcanism,and their relationship to volcanic lithofacies variation, such as central, proximal and distal environments of ore formation. The sedimentary hematite deposits are widespread in China, among which the "Xuanlong-type" in the North China Craton and the "Ningxiang-type" in the South China Block are the most economically important. All these deposits formed during transgressions in a shallow-marine environment. Magmatic Ti-Fe-(V)deposits are dominantly distributed in the Panxi area in Sichuan province and Chengde area in Hebei province. They are dominated low-grade disseminated ores, and unlike the other types of iron deposits, associated sulfide deposits are absent, with magnetite, titanomagnetite and ilmenite as the dominant ore minerals. In the Panxi area in the central Emeishan large igneous province along the western margin of South China Block, the ores are hosted in the ca. 260 Ma mafic layered intrusions, whereas the ores in the Chengde area are associated with the Mesoproterozoic anorthosite complex. The distinct spatio-temporal characteristics of the various iron deposits in China correlate with the multiple tectonomagmatic events associated with the prolonged geological history of the region involving accretion, assembly and rifting.

Keywords: large igneous province; yangtze-river valley; xinjie layered intrusion; hf isotopic constraints; eastern hebei province; asian orogenic belt; south china; sw china; ore-deposits; formation age

来源出版物: Ore Geology Reviews , 2014, 57: 247-263联系邮箱: Zhang, ZC; zczhang@cugb.edu.cn

GEOSCIENCES MULTIDISCIPLINARY 地球科学综合

被引频次: 114

Bedmap2: improved ice bed, surface and thickness datasets for Antarctica

Fretwell, P; Pritchard, HD; Vaughan, DG; et al.

Abstract: We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60 degrees S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation(Bedmap1)in 2001. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1. In most parts of Antarctica the subglacial landscape is visible in much greater detail than was previously available and the improved data-coverage has in many areas revealed the full scale of mountain ranges, valleys, basins and troughs, only fragments of which were previously indicated in local surveys. The derived statistics for Bedmap2 show that the volume of ice contained in the Antarctic ice sheet(27 million km3)and its potential contribution to sea-level rise(58 m)are similar to those of Bedmap1, but the mean thickness of the ice sheet is 4.6% greater, the mean depth of the bed beneath the grounded ice sheet is 72 m lower and the area of ice sheet grounded on bed below sea level is increased by 10 %. The Bedmap2 compilation highlights several areas beneath the ice sheet where the bed elevation is substantially lower than the deepest bed indicated by Bedmap1. These products, along with grids of data coverage and uncertainty, provide new opportunities for detailed modelling of the past and future evolution of the Antarctic ice sheets.

Keywords: digital elevation model; satellite radar; east antarctica; west antarctica; sheet; stream; sea; altimetry; gravity; bathymetry

来源出版物: Cryosphere , 2013, 7(1): 375-393联系邮箱: Fretwell, P; ptf@bas.ac.uk

被引频次: 87

Introduction to tectonics of China

Zheng, YF; Xiao, WJ; Zhao, GC

Abstract: The continental crust of China is a mosaic of cratonic blocks and orogenic belts, containing small cratons and terranes with various tectonic settings. They have diverse origins and complex histories of amalgamation, and often suffered repeated reworking after multiple episodes of amalgamation. In the last three decades, extensive geological, geochemical and geophysical investigations have been carried out on these cratonic blocks and intervening orogenic belts, producing an abundant amount of new data and competing interpretations. This provides important insights into understanding the formation and evolution of the Chinese continents. The papers assembled in this volume present a timely and comprehensive overview on major advancements and controversial issues related to the formation and evolution of continental crust in China. Complex tectonic histories were experienced not only by the large-scale cratonic blocks and orogenic belts, but also by small-scale terranes and orogens between and inside these blocks. Nevertheless, our understanding of lithotectonic units and geological processes has been greatly advanced by recent studies of zirconology and geochemistry for various rock types from major petrotectonic units in China. It has been further advanced from integrated interpretations of geochemical and petrological data for petrogenesis of magmatic rocks. An overview of these observations and interpretations provides new insights into understanding the continental plate tectonics and the chemical geodynamics of subduction zones.

Keywords: asian orogenic belt; pb zircon geochronology; pressure metamorphic rocks; ultrahigh-temperature metamorphism; precambrian crustal evolution; continental subduction zones; large igneous province; liao-ji belt; hf-o isotope; north china

来源出版物: Gondwana Research , 2013, 23(4): 1189-1206联系邮箱: Zheng, YF; yfzheng@ustc.edu.cn

被引频次: 86

The origin and pre-Cenozoic evolution of the Tibetan Plateau

Zhu, DC; Zhao, ZD; Niu, YL; et al.

Abstract: Different hypotheses have been proposed for the origin and pre-Cenozoic evolution of the Tibetan Plateau as a result of several collision events between a series of Gondwana-derived terranes(e.g., Qiangtang, Lhasa and India)and Asian continent since the early Paleozoic. This paper reviews and reevaluates these hypotheses in light of new data from Tibet including(1)the distribution of major tectonic boundaries and suture zones,(2)basement rocks and their sedimentary covers,(3)magmatic suites, and(4)detrital zircon constraints from Paleozoic metasedimentary rocks. The Western Qiangtang, Amdo, and Tethyan Himalaya terranes have the Indian Gondwana origin, whereas the Lhasa Terrane shows an Australian Gondwana affinity. The Cambrian magmatic record in the Lhasa Terrane resulted from the subduction of the proto-Tethyan Ocean lithosphere beneath the Australian Gondwana. The newly identified late Devonian granitoids in the southern margin of the Lhasa Terrane may represent an extensional magmatic event associated with its rifting, which ultimately resulted in the opening of the Songdo Tethyan Ocean. The Lhasa-northern Australia collision at similar to 263 Ma was likely responsible for the initiation of a southward-dipping subduction of the Bangong-Nujiang Tethyan Oceanic lithosphere. The Yarlung-Zangbo Tethyan Ocean opened as a back-arc basin in the late Triassic, leading to the separation of the Lhasa Terrane from northern Australia. The subsequent northward subduction of the Yarlung-Zangbo Tethyan Ocean lithosphere beneath the Lhasa Terrane may have been triggered by the Qiangtang-Lhasa collision in the earliest Cretaceous. The mafic dike swarms(ca. 284 Ma)in the Western Qiangtang originated from the Panjal plume activity that resulted in continental rifting and its separation from the northern Indian continent. The subsequent collision of the Western Qiangtang with the Eastern Qiangtang in the middle Triassic was followed by slab breakoff that led to the exhumation of the Qiangtang metamorphic rocks. This collision may have caused the northward subduction initiation of the Bangong-Nujiang Ocean lithosphere beneath the Western Qiangtang. Collision-related coeval igneous rocks occurring on both sides of the suture zone and the within-plate basalt affinity of associated mafic lithologies suggest slab breakoff-induced magmatism in a continent-continent collision zone. This zone may be the site of net continental crust growth, as exemplified by the Tibetan Plateau.

Keywords: zircon u-pb; zangbo suture zone; india-asia collision; southern lhasa terrane; early paleozoic tectonism; bangong-nujiang suture;mount everest region; hf isotopic analyses; western-australia; tethyan himalaya

来源出版物: Gondwana Research , 2013, 23(4): 1429-1454联系邮箱: Zhu, DC; dchengzhu@163.com

被引频次: 84

Paleozoic multiple accretionary and collisional tectonics of the Chinese Tianshan orogenic collage

Xiao, WJ; Windley, BF; Allen, MB; et al.

Abstract: Subduction-related accretion in the Junggar-Balkash and South Tianshan Oceans(Paleo-Asian Ocean), mainly in the Paleozoic,gave rise to the present 2400 km-long Tianshan orogenic collage that extends from the Aral Sea eastwards through Uzbekistan, Tajikistan,Kyrgyzstan, to Xinjiang in China. This paper provides an up-to-date along-strike synthesis of this orogenic collage and a new tectonic model to explain its accretionary evolution.

The northern part of the orogenic collage developed by consumption of the Junggar-Balkash Ocean together with Paleozoic island arcs(Northern Ili, Issyk Kul, and Chatkal)located in the west, which may have amalgamated into a composite arc in the Paleozoic in the west and by addition of another two, roughly parallel, arcs(Dananhu and Central Tianshan)in the east. The western composite arc and the eastern Dananhu and Central Tianshan arcs formed a late Paleozoic archipelago with multiple subduction zones. The southern part of the orogenic collage developed by the consumption of the South Tianshan Ocean which gave rise to a continuous accretionary complex(Kokshaal-Kumishi), which separated the Central Tianshan in the east and other Paleozoic arcs in the west from cratons(Tarim and Karakum)to the south. Cross-border correlations of this accretionary complex indicate a general southward and oceanward accretion by northward subduction in the early Paleozoic to Permian as recorded by successive southward juxtaposition of ophiolites, slices of ophiolitic melanges,cherts, island arcs, olistostromes, blueschists, and turbidites, which are mainly Paleozoic in age, with the youngest main phase being Late Carboniferous-Permian. The initial docking of the southerly Tarim and Karakum cratons to this complicated late Paleozoic archipelago and accretionary complexes occurred in the Late Carboniferous-Early Permian in the eastern part of the Tianshan and in the Late Permian in the western part, which might have terminated collisional deformation on this suture zone. The final stages of closure of the Junggar-Balkash Ocean resembled the small ocean basin scenario of the Mediterranean Sea in the Cenozoic. In summary, the history of the Altaids is characterized by complicated multiple accretionary and collisional tectonics.

Keywords: phanerozoic crustal growth; southern tien-shan; p-t path; carboniferous volcanic-rocks; mafic-ultramafic intrusions; large igneous province; nd isotopic evidence; ma mantle plume; a-type granites; nw-china

来源出版物: Gondwana Research , 2013, 23(4): 1316-1341联系邮箱: Xiao, WJ; wj-xiao@mail.igcas.ac.cn

被引频次: 67

Metallogeny of the North China Craton: Link with secular changes in the evolving Earth

Zhai, MG; Santosh, M

Abstract: The North China Craton(NCC)has experienced a complex geological evolution since the early Precambrian, and carries important records of secular changes in tectonics and metallogeny. Here we synthesize the salient geological and tectonic features of the evolution and destruction of the NCC vis-a-vis major metallogenic events, and the formation of potential ore deposits. We identify a close relationship between the major geological events in the NCC and those reported elsewhere on the globe. We trace the records of a regular change in the pattern of metallogeny, mineral deposit character, spatial distribution and genetic mechanisms, which closely match the timing and styles of the major geological and tectonic events in this craton.

The NCC went through five major tectonic cycles:(1)Neoarchean crustal growth and stabilization,(2)Paleoproterozoic rifting-subduction-accretion-collision with imprints of the Great Oxidation Event(GOE),(3)Late Paleoproterozoic-Neoproterozoic multi-stage rifting,(4)Paleozoic orogenesis at the margins of the craton, and(5)Mesozoic extensional tectonics associated with lithospheric thinning and decratonization. Coinciding with these major geological events are five major metallogenic systems identified as follows:(I)an Archean BIF system,(2)Paleoproterozoic Cu-Pb-Zn and Mg-B systems,(3)a Mesoproterozoic REE-Fe-Pb-Zn system,(4)a Paleozoic orogenic Cu-Mo system, and(5)Mesozoic intracontinental Au and Ag-Pb-Zn and Mo systems. The ore-deposit types in each of these metallogenic systems show distinct characteristics and tectonic affinities. From Early Precambrian through Late Precambrian to Paleozoic and Mesozoic, the NCC records a transition from primitive- to modern-style plate tectonics. Evidence for imbricated oceanic plate stratigraphy in a subduction-accretion setting, and collisional orogenesis along at least three major zones of ocean closure are documented. Major transitions in tectonic style and surface environmental changes recorded in other parts of the world are also reflected in the geological history and metallogenic events in the NCC. Large-scale gold deposits formed through intraplate tectonics during the Mesozoic provide important insights into mantle dynamics and crust-mantle interaction associated with lithospheric thinning and craton destruction. The NCC provides one of the best examples for documenting secular changes in the geological history and metallogenic epochs of an evolving Earth.

Keywords: zircon u-pb; sino-korean craton; ultrahigh-temperature metamorphism; jiaodong gold province; great oxidation event; asian orogenic belt; ore-forming fluids; inner-mongolia; tectonic evolution; columbia supercontinent

来源出版物: Gondwana Research , 2013, 24(1): 275-297联系邮箱: Zhai, MG; mgzhai@mail.igcas.ac.cn

GERIATRICS GERONTOLOGY 老年医学和老年学

被引频次: 87

Frailty Consensus: A Call to Action

Morley, JE; Vellas, B; van Kan, GA; et al.

Abstract: Frailty is a clinical state in which there is an increase in an individual's vulnerability for developing increased dependency and/or mortality when exposed to a stressor. Frailty can occur as the result of a range of diseases and medical conditions. A consensus group consisting of delegates from 6 major international, European, and US societies created 4 major consensus points on a specific form of frailty: physical frailty.

1. Physical frailty is an important medical syndrome. The group defined physical frailty as "a medical syndrome with multiple causes and contributors that is characterized by diminished strength, endurance, and reduced physiologic function that increases an individual's vulnerability for developing increased dependency and/or death."

2. Physical frailty can potentially be prevented or treated with specific modalities, such as exercise, protein-calorie supplementation, vitamin D, and reduction of polypharmacy.

3. Simple, rapid screening tests have been developed and validated, such as the simple FRAIL scale, to allow physicians to objectively recognize frail persons.

4. For the purposes of optimally managing individuals with physical frailty, all persons older than 70 years and all individuals with significant weight loss(≥5%)due to chronic disease should be screened for frailty.

Keywords: placebo-controlled trial; older-adults; elderly-people; nursing-home; vitamin-d; protein supplementation; clinical-practice; deficit accumulation; functional decline; screening tools

来源出版物: Journal of The American Medical Directors Association , 2013, 14(6): 392-397联系邮箱: Morley, JE; morley@slu.edu

被引频次: 39

Sarcopenia and mortality risk in frail older persons aged 80 years and older: results from ilSIRENTE study

Landi, F; Cruz-Jentoft, AJ; Liperoti, R; et al.

Abstract: Background and aims: sarcopenia has been indicated as a reliable marker of frailty and poor prognosis among the oldest indi-viduals. We evaluated the impact of sarcopenia on the risk of all-cause death in a population of frail older persons living in community.

Methods: we analysed data from the Aging and Longevity Study, a prospective cohort study that collected data on all subjects aged 80 years and older residing in the Sirente geographic area(n=364). The present analysis was conducted among those subjects who were between 80 and 85 years of age at the time of the baseline assessment(n=197). The main outcome measure was all-cause mortality over 7-year follow-up. According to the European Working Group on Sarcopenia in Older People(EWGSOP)criteria, the diagnosis of sarcopenia required the documentation of low muscle mass and the documentation of either low muscle strength or low physical performance. Cox proportional regression models were used to estimate crude and adjusted hazard ratios and 95% confidence intervals of death by the presence of sarcopenia.

Results: using the EWGSOP-suggested criteria, 43 subjects with sarcopenia(21.8%)were identified. During the 7-year follow-up, 29(67.4%)participants died among subjects with sarcopenia compared with 63 subjects(41.2%)without sarcopenia(P<0.001). After adjusting for potential confounders including age, gender, education, activities of daily living(ADL)impairment, body mass index, hypertension,congestive heart failure, chronic obstructive pulmonary disease, number of diseases, TNF-alpha, participants with sarcopenia had a higher risk of death for all causes compared with non-sarcopenic subjects(HR: 2.32, 95% CI: 1.01-5.43).

Conclusions: our results obtained from a representative sample of very old and frail subjects show that sarcopenia is associated with mortality independently of age and other clinical and functional variables.

Keywords: handgrip strength; muscle mass; community; care; performance; definition; prevalence; residents; diagnosis; consensus

来源出版物: Age and Ageing , 2013, 42(2): 203-209联系邮箱: Landi, F; francesco.landi@rm.unicatt.it

被引频次: 39

Searching for an Operational Definition of Frailty: A Delphi Method Based Consensus Statement. The Frailty Operative Definition-Consensus Conference Project

Rodriguez-Manas, L; Feart, C; Mann, G; et al.

Abstract: Background. There is no consensus regarding the definition of frailty for clinical uses.

Methods. A modified Delphi process was used to attempt to achieve consensus definition. Experts were selected from different fields and organized into five Focus Groups. A questionnaire was developed and sent to experts in the area of frailty. Responses and comments were analyzed using a pre-established strategy. Statements with an agreement more than or equal to 80% were accepted.

Results. Overall, 44% of the statements regarding the concept of frailty and 18% of the statements regarding diagnostic criteria were accepted. There was consensus on the value of screening for frailty and about the identification of six domains of frailty for inclusion in a clinical definition, but no agreement was reached concerning a specific set of clinical/laboratory biomarkers useful for diagnosis.

Conclusions. There is agreement on the usefulness of defining frailty in clinical settings as well as on its main dimensions. However, additional research is needed before an operative definition of frailty can be established.

Keywords: disability; phenotype; health; people

来源出版物: Journals of Gerontology Series A-biological Sciences and Medical Sciences , 2013, 68(1): 62-67

联系邮箱: Rodriguez-Manas, L; lrodriguez.hugf@salud.madrid.org

被引频次: 34

Tau protein kinases: Involvement in Alzheimer's disease

Martin, L; Latypova, X; Wilson, CM; et al.

Abstract: Tau phosphorylation is regulated by a balance between tau kinase and phosphatase activities. Disruption of this equilibrium was suggested to be at the origin of abnormal tau phosphorylation and thereby might contribute to tau aggregation. Thus, understanding the regulation modes of tau phosphorylation is of high interest in determining the possible causes at the origin of the formation of tau aggregates in order to elaborate protection strategies to cope with these lesions in Alzheimer's disease. Among the possible and specific interventions that reverse tau phosphorylation is the inhibition of certain tau kinases. Here, we extensively reviewed tau protein kinases, their physiological roles and regulation, their involvement in tau phosphorylation and their relevance to AD. We also reviewed the most common inhibitory compounds acting on each tau kinase.

Keywords: glycogen-synthase kinase-3; cyclin-dependent kinase-5; amyloid precursor protein; central-nervous-system; helical filament-tau; n-terminal kinase; microtubule-associated proteins; nonreceptor tyrosine kinases; chronic myeloid-leukemia; rat hippocampal-neurons

来源出版物: Ageing Research Reviews , 2013, 12(1): 289-309联系邮箱: Martin, L; lmartin.phd@gmail.com

被引频次: 32

Oxidative stress and cancer: An overview

Sosa, V; Moline, T; Somoza, R; et al.

Abstract: Reactive species, which mainly include reactive oxygen species(ROS), are products generated as a consequence of metabolic reactions in the mitochondria of eukaryotic cells. In normal cells, low-level concentrations of these compounds are required for signal transduction before their elimination. However, cancer cells, which exhibit an accelerated metabolism, demand high ROS concentrations to maintain their high proliferation rate. Different ways of developing ROS resistance include the execution of alternative pathways, which can avoid large amounts of ROS accumulation without compromising the energy demand required by cancer cells. Examples of these processes include the guidance of the glycolytic pathway into the pentose phosphate pathway(PPP)and/or the generation of lactate instead of employing aerobic respiration in the mitochondria. Importantly, ROS levels can be used as a thermostat to monitor the damage that cells can bear. The implications for ROS regulation are highly significant for cancer therapy because commonly used radio- and chemotherapeutic drugs influence tumor outcome through ROS modulation. Moreover, the discovery of novel biomarkers that are able to predict the clinical response to pro-oxidant therapies is a crucial challenge to overcome to allow for the personalization of cancer therapies.

Keywords: epithelial-mesenchymal transition; human breast-cancer; manganese superoxide-dismutase; inducible factor 1-alpha; high aerobic glycolysis; acute myeloid-leukemia; stem-cells; dna-damage; liver-cancer; in-vitro

来源出版物: Ageing Research Reviews , 2013, 12(1): 376-390联系邮箱: LLeonart, ME; matilde.lleonart@vhir.org

HEMATOLOGY 血液学

被引频次: 92

European LeukemiaNet recommendations for the management of chronic myeloid leukemia: 2013

Baccarani, M; Deininger, MW; Rosti, G; et al.

Abstract: Advances in chronic myeloid leukemia treatment, particularly regarding tyrosine kinase inhibitors, mandate regular updating of concepts and management. A European LeukemiaNet expert panel reviewed prior and new studies to update recommendations made in 2009. We recommend as initial treatment imatinib, nilotinib, or dasatinib. Response is assessed with standardized real quantitative polymerase chain reaction and/or cytogenetics at 3, 6, and 12 months. BCR-ABL1 transcript levels ≤10% at 3 months, <1% at 6 months, and≤0.1% from 12 months onward define optimal response, whereas >10% at 6 months and >1% from 12 months onward define failure, mandating a change in treatment. Similarly, partial cytogenetic response(PCyR)at 3 months and complete cytogenetic response(CCyR)from 6 months onward define optimal response, whereas no CyR(Philadelphia chromosome-positive [Ph1]>95%)at 3 months, less than PCyR at 6 months, and less than CCyR from 12 months onward define failure. Between optimal and failure, there is an intermediate warning zone requiring more frequent monitoring. Similar definitions are provided for response to second-line therapy. Specific recommendations are made for patients in the accelerated and blastic phases, and for allogeneic stem cell transplantation. Optimal responders should continue therapy indefinitely, with careful surveillance, or they can be enrolled in controlled studies of treatment discontinuation once a deeper molecular response is achieved.

Keywords: tyrosine kinase inhibitors; diagnosed chronic-phase; chronic myelogenous leukemia; patients receiving imatinib; major cytogenetic response; subcutaneous omacetaxine mepesuccinate; complete molecular remission; arterial occlusive disease; bcr-abl1 transcript levels; stem-cell transplantation

来源出版物: Blood , 2013, 122(6): 872-884联系邮箱: Baccarani, M; michele.baccarani@unibo.it

被引频次: 88

Investigation of the freely available easy-to-use software 'EZR' for medical statistics

Kanda, Y

Abstract: Although there are many commercially available statistical software packages, only a few implement a competing risk analysis or a proportional hazards regression model with time-dependent covariates, which are necessary in studies on hematopoietic SCT. In addition, most packages are not clinician friendly, as they require that commands be written based on statistical languages. This report describes the statistical software 'EZR'(Easy R), which is based on R and R commander. EZR enables the application of statistical functions that are frequently used in clinical studies, such as survival analyses, including competing risk analyses and the use of time-dependent covariates,receiver operating characteristics analyses, meta-analyses, sample size calculation and so on, by point-and-click access. EZR is freely available on our website(http://www.jichi.ac.jp/saitama-sct/SaitamaHP.files/statmed.html)and runs on both Windows(Microsoft Corporation, USA)and Mac OS X(Apple, USA). This report provides instructions for the installation and operation of EZR.

Keywords: bone-marrow transplants; competing risk; cumulative incidence; clinician; tests; guide

来源出版物: Bone Marrow Transplantation , 2013, 48(3): 452-458联系邮箱: Kanda, Y; ycanda-tky@umin.ac.jp

被引频次: 79

A specific antidote for dabigatran: functional and structural characterization

Schiele, F; van Ryn, J; Canada, K; et al.

Abstract: Dabigatran etexilate is a direct thrombin inhibitor and used widely as an anticoagulant for the prevention of stroke in patients with atrial fibrillation. However, anticoagulation therapy can be associated with an increased risk of bleeding. Here, we present data on the identification, humanization, and in vitro pharmacology of an antidote for dabigatran(aDabi-Fab). The X-ray crystal structure of dabigatran in complex with the antidote reveals many structural similarities of dabigatran recognition compared with thrombin. By a tighter network of interactions, the antidote achieves an affinity for dabigatran that is similar to 350 times stronger than its affinity for thrombin. Despite the structural similarities in the mode of dabigatran binding, the antidote does not bind known thrombin substrates and has no activity in coagulation tests or platelet aggregation. In addition we demonstrate that the antidote rapidly reversed the anticoagulant activity of dabigatran in vivo in a rat model of anticoagulation. This is the first report of a specific antidote for a next-generation anticoagulant that may become a valuable tool in patients who require emergency procedures.

Keywords: direct thrombin inhibitor; anticoagulant activity; reversal; antibody; etexilate; fragments; toxicity; therapy

来源出版物: Blood , 2013, 121(18): 3554-3562联系邮箱: Litzenburger, T; tobias.litzenburger@boehringer-ingelheim.com

被引频次: 76

Guidelines for the management of hemophilia

Srivastava, A; Brewer, AK; Mauser-Bunschoten, EP; et al.

Abstract: Hemophilia is a rare disorder that is complex to diagnose and to manage. These evidence-based guidelines offer practical recommendations on the diagnosis and general management of hemophilia, as well as the management of complications including musculoskeletal issues, inhibitors, and transfusion-transmitted infections. By compiling these guidelines, the World Federation of Hemophilia aims to assist healthcare providers seeking to initiate and/or maintain hemophilia care programs, encourage practice harmonization around the world and, where recommendations lack adequate evidence, stimulate appropriate studies.

Keywords: immune tolerance induction; total knee arthroplasty; hepatitis-b-vaccine; quality-of-life; term-follow-up; inherited bleeding disorders; center doctors organization; factor-viii concentrate; ischemic-heart-disease; von-willebrand-disease

来源出版物: Haemophilia , 2013, 19(1): E1-E47联系邮箱: Srivastava, A; aloks@cmcvellore.ac.in

被引频次: 60

Stromal cells from the adipose tissue-derived stromal vascular fraction and culture expanded adipose tissue-derived stromal/stem cells: a joint statement of the International Federation for Adipose Therapeutics and Science(IFATS)and the International Society for Cellular Therapy(ISCT)

Bourin, P; Bunnell, BA; Casteilla, L; et al.

Abstract: Background aims. Adipose tissue is a rich and very convenient source of cells for regenerative medicine therapeutic approaches. However, a characterization of the population of adipose-derived stromal and stem cells(ASCs)with the greatest therapeutic potential remains unclear. Under the authority of International Federation of Adipose Therapeutics and International Society for Cellular Therapy, this paper sets out to establish minimal definitions of stromal cells both as uncultured stromal vascular fraction(SVF)and as an adherent stromal/stem cells population. Methods. Phenotypic and functional criteria for the identification of adipose-derived cells were drawn from the literature. Results. In the SVF, cells are identified phenotypically by the following markers: CD45-CD235a-CD31-CD34+. Added value may be provided by both a viability marker and the following surface antigens: CD13, CD73, CD90 and CD105. The fibroblastoid colony-forming unit assay permits the evaluation of progenitor frequency in the SVF population. In culture, ASCs retain markers in common with other mesenchymal stromal/stem cells(MSCs), including CD90, CD73, CD 105, and CD44 and remain negative for CD45 and CD31. They can be distinguished from bone-marrow-derived MSCs by their positivity for CD36 and negativity for CD106. The CFU-F assay is recommended to calculate population doublings capacity of ASCs. The adipocytic, chondroblastic and osteoblastic differentiation assays serve to complete the cell identification and potency assessment in conjunction with a quantitative evaluation of the differentiation either biochemically or by reverse transcription polymerase chain reaction. Conclusions. The goal of this paper is to provide initial guidance for the scientific community working with adipose-derived cells and to facilitate development of international standards based on reproducible parameters.

Keywords: mesenchymal stem-cells; human-bone-marrow; hematopoietic stem; progenitor cells; in-vitro; subpopulations; translation;features; surface

来源出版物: Cytotherapy , 2013, 15(6): 641-648联系邮箱: Bourin, P; p.bourin@csa21.com

HORTICULTURE 园艺学

被引频次: 29

Accessing complex crop genomes with next-generation sequencing

Edwards, D; Batley, J; Snowdon, RJ

Abstract: Many important crop species have genomes originating from ancestral or recent polyploidisation events. Multiple homoeologous gene copies, chromosomal rearrangements and amplification of repetitive DNA within large and complex crop genomes can considerably complicate genome analysis and gene discovery by conventional, forward genetics approaches. On the other hand, ongoing technological advances in molecular genetics and genomics today offer unprecedented opportunities to analyse and access even more recalcitrant genomes. In this review, we describe next-generation sequencing and data analysis techniques that vastly improve our ability to dissect and mine genomes for causal genes underlying key traits and allelic variation of interest to breeders. We focus primarily on wheat and oilseed rape, two leading examples of major polyploid crop genomes whose size or complexity present different, significant challenges. In both cases, the latest DNA sequencing technologies, applied using quite different approaches, have enabled considerable progress towards unravelling the respective genomes. Our ability to discover the extent and distribution of genetic diversity in crop gene pools, and its relationship to yield and quality-related traits, is swiftly gathering momentum as DNA sequencing and the bioinformatic tools to deal with growing quantities of genomic data continue to develop. In the coming decade, genomic and transcriptomic sequencing, discovery and high-throughput screening of single nucleotide polymorphisms, presence-absence variations and other structural chromosomal variants in diverse germplasm collections will give detailed insight into the origins, domestication and available trait-relevant variation of polyploid crops, in the process facilitating novel approaches and possibilities for genomics-assisted breeding.

Keywords: nucleotide polymorphism discovery; chickpea cicer-arietinum; triticum-aestivum l.; brassica-napus; arabidopsis-thaliana; snp discovery; bread wheat; wide association; polyploid plants; chromosome 3b

来源出版物: Theoretical and Applied Genetics , 2013, 126(1): 1-11联系邮箱: Batley, J; j.batley@uq.edu.au

被引频次: 22

Characterisation of 'Braeburn' browning disorder by means of X-ray micro-CT

Herremans, E; Verboven, P; Bongaers, E; et al.

Abstract: Unfavourable gas conditions during controlled atmosphere storage may cause browning symptoms in 'Braeburn' apple fruit('Braeburn' browning disorder or BBD). These symptoms are likely to reflect massive changes in the microstructure of the fruit tissue. In this study, individual cells, the internal air network and the 3-D distribution of pores inside 'Braeburn' apple tissue were examined using high resolution X-ray micro computed tomography. Different stages of BBD could be clearly resolved on the virtual cross-sections, granting a unique 3-D insight in tissue flooding and formation of cavities in 'Braeburn' tissue during the development of the disorder. Image analysis methods were applied to extract morphometric parameters such as porosity, anisotropy and connectivity to characterise microstructure. The discriminative power of these descriptors was proven by their ability to classify fruit tissue as healthy and disordered with a success rate of 97%. The observed distinct radial patterns of porosity, anisotropy and connectivity may help in explaining why 'Braeburn' is susceptible to BBD.

Keywords: controlled-atmosphere storage; pyrus-communis l.; conference pears; core breakdown; gas-transport; apple tissue; fruit; quantification; model; microtomography

来源出版物: Postharvest Biology and Technology , 2013, 75: 114-124联系邮箱: Herremans, E; els.herremans@biw.kuleuven.be

被引频次: 18

Large-scale parentage analysis in an extended set of grapevine cultivars(Vitis vinifera L.)

Lacombe, T; Boursiquot, JM; Laucou, V; et al.

Abstract: Inheritance of nuclear microsatellite markers(nSSR)has been proved to be a powerful tool to verify or uncover the parentage of grapevine cultivars. The aim of the present study was to undertake an extended parentage analysis using a large sample of Vitis vinifera cultivars held in the INRA "Domaine de Vassal" Grape Germplasm Repository(France). A dataset of 2344 unique genotypes(i.e. cultivars without synonyms, clones or mutants)identified using 20 nSSR was analysed with FAMOZ software. Parentages showing a logarithm of odds score higher than 18 were validated in relation to the historical data available. The analysis first revealed the full parentage of 828 cultivars resulting in:(1)315 original full parentages uncovered for traditional cultivars,(2)100 full parentages confirming results established with molecular markers in prior papers and 32 full parentages that invalidated prior results,(3)255 full parentages confirming pedigrees as disclosed by the breeders and(4)126 full parentages that invalidated breeders' data. Second, incomplete parentages were determined in 1,087 cultivars due to the absence of complementary parents in our cultivar sample. Last, a group of 276 genotypes showed no direct relationship with any other cultivar in the collection. Compiling these results from the largest set of parentage data published so farboth enlarges and clarifies our knowledge of the genetic constitution of cultivated V. vinifera germplasm. It also allows the identification of the main genitors involved in varietal assortment evolution and grapevine breeding.

Keywords: genetic diversity; pedigree reconstruction; microsatellite analysis; chloroplast dna; wine grapes; varieties; markers; origin; relatedness; populations

来源出版物: Theoretical and Applied Genetics , 2013, 126(2): 401-414联系邮箱: Lacombe, T; lacombe@supagro.inra.fr

被引频次: 17

Genetic dissection of aroma volatile compounds from the essential oil of peach fruit: QTL analysis and identification of candidate genes using dense SNP maps

Eduardo, I; Chietera, G; Pirona, R; et al.

Abstract: Volatile organic compounds(VOCs)in plants are involved in aroma and pest resistance. These compounds form a complex mixture whose composition is specific to species and often to varieties. Despite their importance as essential factors that determine peach fruit quality, understanding of molecular, genetic, and physiological mechanisms underlying aroma formation is limited. The aim of this study was the identification in peach of quantitative trait loci(QTLs)for fruit VOCs to understand their genetic basis using an F1 population of 126 seedlings deriving from the cross between "Bolero"(B)and "OroA"(O), two peach cultivars differing in their aroma profile. Dense single nucleotide polymorphism(SNP)and SSR maps covering the eight linkage groups of the peach genome were constructed by genotyping with the International Peach SNP Consortium peach SNP array v1, and data for 23 VOCs with high or unknown "odor activity value" were obtained by gas chromatography-mass spectrometry analysis of fruit essential oil in the years 2007 and 2008. A total of 72 QTLs were identified, most consistent in both years. QTLs were identified for the 23 VOCs studied, including three major QTLs for nonanal, linalool, and for p-menth-1-en-9-al stable in both years. Collocations between candidate genes and major QTLs were identified taking advantage of the peach genome sequence: genes encoding two putative terpene synthases and one lipoxygenase(Lox)might be involved in the biosynthesis of linalool and p-menth-1-en-9-al, and nonanal, respectively. Implications for marker-assisted selection and future research on the subject are discussed.

Keywords: persica l. batsch; hydroperoxide lyase activities; marker-assisted selection; powdery mildew resistance; knot nematode resistance; quantitative trait loci; red skin color; linkage map; molecular markers; prunus-davidiana

来源出版物: Tree Genetics & Genomes , 2013, 9(1): 189-204联系邮箱: Rossini, L; laura.rossini@unimi.it

被引频次: 17

High density SNP mapping and QTL analysis for fruit quality characteristics in peach(Prunus persica L.)

Martinez-Garcia, PJ; Parfitt, DE; Ogundiwin, EA; et al.

Abstract: Single nucleotide polymorphisms(SNPs)were used to construct an integrated SNP linkage map of peach(Prunus persica(L.)Batsch). A set of 1,536 SNPs were evaluated with the GoldenGateA(R)Genotyping assay in two mapping populations, Pop-DF, and Pop-DG. After genotyping and filtering, a final set of 1400 high quality SNPs in Pop-DF and 962 in Pop-DG with full map coverage were selected and used to construct two linkage maps with JoinMapA(R)4.0. The Pop-DF map covered 422 cM of the peach genome and included 1037 SNP markers, and Pop-DG map covered 369 cM and included 738 SNPs. A consensus map was constructed with 588 SNP markers placed in eight linkage groups(n = 8 for peach), with map coverage of 454 cM and an average distance of 0.81 cM/marker site. Placements of SNPs on the "peach v1.0" physical map were compared to placement on the linkage maps and several differences were observed. Using the SNP linkage map of Pop-DG and phenotypic data collected for three harvest seasons, a QTL analysis for fruit quality traits and chilling injury symptoms was carried out with the mapped SNPs. Significant QTL effects were detected for mealiness(M)and flesh bleeding(FBL)QTLs on linkage group 4 and flesh browning(FBr)on linkage group 5. This study represents one of the first examples of QTL detection for quality traits and chilling injury symptoms using a high-density SNP map in a single peach F1 family.

Keywords: genetic-linkage map; chilling injury; rapd markers; interspecific cross; molecular markers; noncoding regions; aflp markers;construction; genome; batsch

来源出版物: Tree Genetics & Genomes , 2013, 9(1): 19-36联系邮箱: Martinez-Garcia, PJ; pjmartinezgarcia@ucdavis.edu

IMAGING SCIENCE PHOTOGRAPHIC TECHNOLOGY 成像科学与照相技术

被引频次: 56

Satellite-derived land surface temperature: Current status and perspectives

Li, ZL; Tang, BH; Wu, H; et al.

Abstract: Land surface temperature(LST)is one of the key parameters in the physics of land surface processes from local through global scales. The importance of LST is being increasingly recognized and there is a strong interest in developing methodologies to measure LST from space. However, retrieving LST is still a challenging task since the LST retrieval problem is ill-posed. This paper reviews the currentstatus of selected remote sensing algorithms for estimating LST from thermal infrared(TIR)data. A brief theoretical background of the subject is presented along with a survey of the algorithms employed for obtaining LST from space-based TIR measurements. The discussion focuses on TIR data acquired from polar-orbiting satellites because of their widespread use, global applicability and higher spatial resolution compared to geostationary satellites. The theoretical framework and methodologies used to derive the LST from the data are reviewed followed by the methodologies for validating satellite-derived LST. Directions for future research to improve the accuracy of satellite-derived LST are then suggested.

Keywords: thermal-infrared data; split-window algorithm; track scanning radiometer; high-resolution radiometer; neural-network technique; remote-sensing data; emissivity separation algorithm; 2-step physical algorithm; passive microwave data; in-flight validation

来源出版物: Remote Sensing of Environment , 2013, 131: 14-37联系邮箱: Li, ZL; lizl@igsnrr.ac.cn

被引频次: 47

Finer resolution observation and monitoring of global land cover: first mapping results with Landsat TM and ETM+ data

Gong, P; Wang, J; Yu, L; et al.

Abstract: We have produced the first 30 m resolution global land-cover maps using Landsat Thematic Mapper(TM)and Enhanced Thematic Mapper Plus(ETM+)data. We have classified over 6600 scenes of Landsat TM data after 2006, and over 2300 scenes of Landsat TM and ETM+ data before 2006, all selected from the green season. These images cover most of the world's land surface except Antarctica and Greenland. Most of these images came from the United States Geological Survey in level L1T(orthorectified). Four classifiers that were freely available were employed, including the conventional maximum likelihood classifier(MLC), J4.8 decision tree classifier, Random Forest(RF)classifier and support vector machine(SVM)classifier. A total of 91433 training samples were collected by traversing each scene and finding the most representative and homogeneous samples. A total of 38664 test samples were collected at preset, fixed locations based on a globally systematic unaligned sampling strategy. Two software tools, Global Analyst and Global Mapper developed by extending the functionality of Google Earth, were used in developing the training and test sample databases by referencing the Moderate Resolution Imaging Spectroradiometer enhanced vegetation index(MODIS EVI)time series for 2010 and high resolution images from Google Earth. A unique land-cover classification system was developed that can be crosswalked to the existing United Nations Food and Agriculture Organization(FAO)land-cover classification system as well as the International Geosphere-Biosphere Programme(IGBP)system. Using the four classification algorithms, we obtained the initial set of global land-cover maps. The SVM produced the highest overall classification accuracy(OCA)of 64.9% assessed with our test samples, with RF(59.8%), J4.8(57.9%), and MLC(53.9%)ranked from the second to the fourth. We also estimated the OCAs using a subset of our test samples(8629)each of which represented a homogeneous area greater than 500 m × 500 m. Using this subset, we found the OCA for the SVM to be 71.5%. As a consistent source for estimating the coverage of global land-cover types in the world, estimation from the test samples shows that only 6.90% of the world is planted for agricultural production. The total area of cropland is 11.51% if unplanted croplands are included. The forests, grasslands, and shrublands cover 28.35%, 13.37%, and 11.49% of the world, respectively. The impervious surface covers only 0.66% of the world. Inland waterbodies, barren lands, and snow and ice cover 3.56%, 16.51%, and 12.81% of the world, respectively.

Keywords: earth observation data; remotely-sensed data; satellite data; research priorities; accuracy assessment; use classification; brazilian amazon; aerial imagery; large areas; vegetation

来源出版物: International Journal of Remote Sensing , 2013, 34(7): 2607-2654联系邮箱: Gong, P; penggong@berkeley.edu

被引频次: 36

Land surface emissivity retrieval from satellite data

Li, ZL; Wu, H; Wang, N; et al.

Abstract: As an intrinsic property of natural materials, land surface emissivity(LSE)is an important surface parameter and can be derived from the emitted radiance measured from space. Besides radiometric calibration and cloud detection, two main problems need to be resolved to obtain LSE values from space measurements. These problems are often referred to as land surface temperature(LST)and emissivity separation from radiance at ground level and as atmospheric corrections in the literature. To date, many LSE retrieval methods have been proposed with the same goal but different application conditions, advantages, and limitations. The aim of this article is to review these LSE retrieval methods and to provide technical assistance for estimating LSE from space. This article first gives a description of the theoretical basis of LSE measurements and then reviews the published methods. For clarity, we categorize these methods into(1)(semi-)empirical or theoretical methods,(2)multi-channel temperature emissivity separation(TES)methods, and(3)physically based methods(PBMs). This article also discusses the validation methods, which are of importance in verifying the uncertainty and accuracy of retrieved emissivity. Finally, the prospects for further developments are given.

Keywords: thermal infrared data; airborne imaging spectrometer; reflection radiometer aster; 2-step physical algorithm; m atmospheric window; remote-sensing data; mu-m; directional emissivity; bidirectional reflectance; split-window

来源出版物: International Journal of Remote Sensing , 2013, 34(9-10): 3084-3127联系邮箱: Li, ZL; lizl@igsnrr.ac.cn

被引频次: 31

Making better use of accuracy data in land change studies: Estimating accuracy and area and quantifying uncertainty using stratified estimation

Olofsson, P; Foody, GM; Stehman, SV; et al.

Abstract: The area of land use or land cover change obtained directly from a map may differ greatly from the true area of change because of map classification error. An error-adjusted estimator of area can be easily produced once an accuracy assessment has been performed and an error matrix constructed. The estimator presented is a stratified estimator which is applicable to data acquired using popular sampling designs such as stratified random, simple random and systematic(the stratified estimator is often labeled a poststratified estimator for the latter two designs). A confidence interval for the area of land change should also be provided to quantify the uncertainty of the change area estimate. The uncertainty of the change area estimate, as expressed via the confidence interval, can then subsequently be incorporated into an uncertainty analysis for applications using land change area as an input(e.g., a carbon flux model). Accuracy assessments published for land change studies should report the information required to produce the stratified estimator of change area and to construct confidence intervals. However, an evaluation of land change articles published between 2005 and 2010 in two remote sensing journals revealed that accuracy assessments often fail to include this key information. We recommend that land change maps should be accompanied by an accuracy assessment that includes a clear description of the sampling design(including sample size and, if relevant, details of stratification), an error matrix, the area or proportion of area of each category according to the map, and descriptive accuracy measures such as user's, producer's and overall accuracy. Furthermore, mapped areas should be adjusted to eliminate bias attributable to map classification error and these error-adjusted area estimates should be accompanied by confidence intervals to quantify the sampling variability of the estimated area. Using data from the published literature, we illustrate how to produce error-adjusted point estimates and confidence intervals of land change areas. A simple analysis of uncertainty based on the confidence bounds for land change area is applied to a carbon flux model to illustrate numerically that variability in the land change area estimate can have a dramatic effect on model outputs.

Keywords: remotely-sensed data; thematic map accuracy; cover change; classification accuracy; satellite data; tropical deforestation; urban-growth; biodiversity; allocation; inference

来源出版物: Remote Sensing of Environment , 2013, 129: 122-131联系邮箱: Olofsson, P; olofsson@bu.edu

被引频次: 29

Accuracy assessment of NLCD 2006 land cover and impervious surface

Wickham, JD; Stehman, SV; Gass, L; et al.

Abstract: Release of NLCD 2006 provides the first wall-to-wall land-cover change database for the conterminous United States from Landsat Thematic Mapper(TM)data. Accuracy assessment of NLCD 2006 focused on four primary products: 2001 land cover, 2006 land cover, land-cover change between 2001 and 2006, and impervious surface change between 2001 and 2006. The accuracy assessment was conducted by selecting a stratified random sample of pixels with the reference classification interpreted from multi-temporal high resolution digital imagery. The NLCD Level II(16 classes)overall accuracies for the 2001 and 2006 land cover were 79% and 78%, respectively,with Level II user's accuracies exceeding 80% for water, high density urban, all upland forest classes, shrubland, and cropland for both dates. Level I(8 classes)accuracies were 85% for NLCD 2001 and 84% for NLCD 2006. The high overall and user's accuracies for the individual dates translated into high user's accuracies for the 2001-2006 change reporting themes water gain and loss, forest loss, urban gain,and the no-change reporting themes for water, urban, forest and agriculture. The main factor limiting higher accuracies for the change reporting themes appeared to be difficulty in distinguishing the context of grass. We discuss the need for more research on land-cover change accuracy assessment Published by Elsevier Inc.

Keywords: conterminous united-states; validation data set; thematic accuracy; error matrix; classification; database; design; maps; completion; principles

来源出版物: Remote Sensing of Environment , 2013, 130: 294-304联系邮箱: Wickham, JD; wickham.james@epa.gov

IMMUNOLOGY 免疫学

被引频次: 241

Innate lymphoid cells - a proposal for uniform nomenclature

Spits, H; Artis, D; Colonna, M; et al.

Abstract: Innate lymphoid cells(ILCs)are a family of developmentally related cells that are involved in immunity and in tissue development and remodelling. Recent research has identified several distinct members of this family. Confusingly, many different names have been used to characterize these newly identified ILC subsets. Here, we propose that ILCs should be categorized into three groups based on thecytokines that they can produce and the transcription factors that regulate their development and function.

Keywords: natural-killer-cells; transcription factor gata3; tissue-inducer cells; ror-gamma-t; type-2 immunity; in-vivo; inflammation; lung;lineage; precursors

来源出版物: Nature Reviews Immunology , 2013, 13(2): 145-149联系邮箱: Spits, H; hergen.spits@amc.uva.nl

被引频次:159

Fate Mapping Reveals Origins and Dynamics of Monocytes and Tissue Macrophages under Homeostasis

Yona, S; Kim, KW; Wolf, Y; et al.

Abstract: Mononuclear phagocytes, including monocytes, macrophages, and dendritic cells, contribute to tissue integrity as well as to innate and adaptive immune defense. Emerging evidence for labor division indicates that manipulation of these cells could bear therapeutic potential. However, specific ontogenies of individual populations and the overall functional organization of this cellular network are not well defined. Here we report a fate-mapping study of the murine monocyte and macrophage compartment taking advantage of constitutive and conditional CX3CR1 promoter-driven Cre recombinase expression. We have demonstrated that major tissue-resident macrophage populations, including liver Kupffer cells and lung alveolar, splenic, and peritoneal macrophages, are established prior to birth and maintain themselves subsequently during adulthood independent of replenishment by blood monocytes. Furthermore, we have established that short-lived Ly6C+monocytes constitute obligatory steady-state precursors of blood-resident Ly6C-cells and that the abundance of Ly6C+blood monocytes dynamically controls the circulation lifespan of their progeny.

Keywords: dendritic cell-development; mononuclear phagocyte system; mouse bone-marrow; in-vivo; blood monocytes; alveolar macrophages; fluorescent protein; microglia derive; growth-factor; steady-state

来源出版物: Immunity , 2013, 38(1): 79-91联系邮箱: Jung, S; s.jung@weizmann.ac.il

被引频次: 137

Neutrophil recruitment and function in health and inflammation

Kolaczkowska, E; Kubes, P

Abstract: Neutrophils have traditionally been thought of as simple foot soldiers of the innate immune system with a restricted set of pro-inflammatory functions. More recently, it has become apparent that neutrophils are, in fact, complex cells capable of a vast array of specialized functions. Although neutrophils are undoubtedly major effectors of acute inflammation, several lines of evidence indicate that they also contribute to chronic inflammatory conditions and adaptive immune responses. Here, we discuss the key features of the life of a neutrophil, from its release from bone marrow to its death. We discuss the possible existence of different neutrophil subsets and their putative anti-inflammatory roles. We focus on how neutrophils are recruited to infected or injured tissues and describe differences in neutrophil recruitment between different tissues. Finally, we explain the mechanisms that are used by neutrophils to promote protective or pathological immune responses at different sites.

Keywords: acute lung injury; extracellular trap formation; vascular endothelial-cells; colony-stimulating factor; selectin-deficient mice;in-vivo; leukocyte recruitment; p-selectin; transendothelial migration; immune-system

来源出版物: Nature Reviews Immunology , 2013, 13(3): 159-175联系邮箱: Kubes, P; pkubes@ucalgary.ca

被引频次: 134

Tissue-Resident Macrophages Self-Maintain Locally throughout Adult Life with Minimal Contribution from Circulating Monocytes

Hashimoto, D; Chow, A; Noizat, C; et al.

Abstract: Despite accumulating evidence suggesting local self-maintenance of tissue macrophages in the steady state, the dogma remains that tissue macrophages derive from monocytes. Using parabiosis and fate-mapping approaches, we confirmed that monocytes do not show significant contribution to tissue macrophages in the steady state. Similarly, we found that after depletion of lung macrophages, the majority of repopulation occurred by stochastic cellular proliferation in situ in a macrophage colony-stimulating factor(M-Csf)- and granulocyte macrophage(GM)-CSF-dependent manner but independently of interleukin-4. We also found that after bone marrow transplantation, host macrophages retained the capacity to expand when the development of donor macrophages was compromised. Expansion of host macrophages was functional and prevented the development of alveolar proteinosis in mice transplanted with GM-Csf-receptor-deficient progenitors. Collectively, these results indicate that tissue-resident macrophages and circulating monocytes should be classified as mononuclear phagocyte lineages that are independently maintained in the steady state.

Keywords: pulmonary alveolar proteinosis; colony-stimulating factor; hematopoietic stem-cells; gm-csf autoantibodies; chemokine receptor 2; dendritic cells; bone-marrow; mice; origin; differentiation

来源出版物: Immunity , 2013, 38(4): 792-804联系邮箱: Merad, M; miriam.merad@mssm.edu

被引频次: 116

Immunogenic Cell Death in Cancer Therapy

Kroemer, G; Galluzzi, L; Kepp, O; et al.

Abstract: Depending on the initiating stimulus, cancer cell death can be immunogenic or nonimmunogenic. Immunogenic cell death(ICD)involves changes in the composition of the cell surface as well as the release of soluble mediators, occurring in a defined temporal sequence. Such signals operate on a series of receptors expressed by dendritic cells to stimulate the presentation of tumor antigens to T cells. We postulate that ICD constitutes a prominent pathway for the activation of the immune system against cancer, which in turn determines the long-term success of anticancer therapies. Hence, suboptimal regimens(failing to induce ICD), selective alterations in cancer cells(preventing the emission of immunogenic signals during ICD), or defects in immune effectors(abolishing the perception of ICD by the immune system)can all contribute to therapeutic failure. We surmise that ICD and its subversion by pathogens also play major roles in antiviral immune responses.

Keywords: apoptotic calreticulin exposure; anticancer immune-response; in-situ vaccination; find-me signal; colon-cancer; tumor-cells;t-cells; molecular-mechanisms; adaptive immunity; surface exposure

来源出版物: Annual Review of Immunology, 2013, 31: 51-72联系邮箱: Kroemer, G; kroemer@orange.fr

INFECTIOUS DISEASES 传染病学

被引频次: 106

Antimicrobial-Resistant Pathogens Associated with Healthcare-Associated Infections: Summary of Data Reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2009-2010

Sievert, DM; Ricks, P; Edwards, JR; et al.

Abstract: OBJECTIVE. To describe antimicrobial resistance patterns for healthcare-associated infections(HAIs)reported to the National Healthcare Safety Network(NHSN)during 2009-2010.

METHODS. Central line-associated bloodstream infections, catheter-associated urinary tract infections, ventilator-associated pneumonia,and surgical site infections were included. Pooled mean proportions of isolates interpreted as resistant(or, in some cases, nonsusceptible)to selected antimicrobial agents were calculated by type of HAI and compared to historical data.

RESULTS. Overall, 2039 hospitals reported 1 or more HAIs; 1749(86%)were general acute care hospitals, and 1143(56%)had fewer than 200 beds. There were 69475 HAIs and 81139 pathogens reported. Eight pathogen groups accounted for about 80% of reported pathogens: Staphylococcus aureus(16%), Enterococcus spp.(14%), Escherichia coli(12%), coagulase-negative staphylococci(11%), Candida spp.(9%), Klebsiella pneumoniae(and Klebsiella oxytoca; 8%), Pseudomonas aeruginosa(8%), and Enterobacter spp.(5%). The percentage of resistance was similar to that reported in the previous 2-year period, with a slight decrease in the percentage of S. aureus resistant to oxacillins(MRSA). Nearly 20% of pathogens reported from all HAIs were the following multidrug-resistant phenotypes: MRSA(8.5%); vancomycin-resistant Enterococcus(3%); extended-spectrum cephalosporin-resistant K. pneumoniae and K. oxytoca(2%), E. coli(2%), and Enterobacter spp.(2%); and carbapenem-resistant P. aeruginosa(2%), K. pneumoniae/oxytoca(<1%), E. coli(<1%), and Enterobacter spp.(<1%). Among facilities reporting HAIs with 1 of the above gram-negative bacteria, 20%-40% reported at least 1 with the resistant phenotype.

CONCLUSION. While the proportion of resistant isolates did not substantially change from that in the previous 2 years, multidrug-resistant gram-negative phenotypes were reported from a moderate proportion of facilities.

来源出版物: Infection Control and Hospital Epidemiology , 2013, 34(1): 1-14联系邮箱: Fridkin, S; skf0@cdc.gov

被引频次: 101

Middle East respiratory syndrome coronavirus neutralising serum antibodies in dromedary camels: a comparative serological study

Reusken, CBEM; Haagmans, BL; Muller, MA; et al.

Abstract: Background A new betacoronavirus Middle East respiratory syndrome coronavirus(MERS-CoV)has been identified in patients with severe acute respiratory infection. Although related viruses infect bats, molecular clock analyses have been unable to identify direct ancestors of MERS-CoV. Anecdotal exposure histories suggest that patients had been in contact with dromedary camels or goats. We investigated possible animal reservoirs of MERSCoV by assessing specific serum antibodies in livestock.

Methods We took sera from animals in the Middle East(Oman)and from elsewhere(Spain, Netherlands, Chile). Cattle(n=80), sheep(n=40), goats(n=40), dromedary camels(n=155), and various other camelid species(n=34)were tested for specific serum IgG by protein microarray using the receptor-binding Si subunits of spike proteins of MERS-CoV, severe acute respiratory syndrome coronavirus, and human coronavirus 0C43. Results were confirmed by virus neutralisation tests for MERS-CoV and bovine coronavirus.Findings 50 of 50(100%)sera from Omani camels and 15 of 105(14%)from Spanish camels had protein-specific antibodies against MERS-CoV spike. Sera from European sheep, goats, cattle, and other camelids had no such antibodies. MERS-CoV neutralising antibody titres varied between 1/320 and 1/2560 for the Omani camel sera and between 1/20 and 1/320 for the Spanish camel sera. There was no evidence for cross-neutralisation by bovine coronavirus antibodies.

Interpretation MERS-CoV or a related virus has infected camel populations. Both titres and seroprevalences in sera from different locations in Oman suggest widespread infection.

Keywords: bovine coronavirus; bat coronavirus; infection; virus; microarray; sequence; protein; risk; 0C43; EMC

来源出版物: Lancet Infectious Diseases , 2013, 13(10): 859-866联系邮箱: Reusken, CBEM; Chantal.Reusken@RIVM.nl

被引频次: 96

Genetic analysis of novel avian A(H7N9)influenza viruses isolated from patients in China,February to April 2013

Kageyama, T; Fujisaki, S; Takashita, E; et al.

Abstract: Novel influenza viruses of the H7N9 subtype have infected 33 and killed nine people in China as of 10 April 2013. Their haemagglutinin(HA)and neuraminidase genes probably originated from Eurasian avian influenza viruses; the remaining genes are closely related to avian H9N2 influenza viruses. Several characteristic amino acid changes in HA and the PB2 RNA polymerase subunit probably facilitate binding to human-type receptors and efficient replication in mammals, respectively, highlighting the pandemic potential of the novel viruses.

Humans are rarely infected with avian influenza viruses, with the exception of highly pathogenic avian influenza A(H5N1)viruses, which have caused 634 infections and 371 deaths as of 12 March 2013 [ 1]. A few isolated cases of human infection with viruses of the H7N2,H7N3, and H7N5 subtypes have been reported, but none were fatal [2-11]. In 2003, in the Netherlands, 89 people were infected with an influenza virus of the H7N7 subtype that caused conjunctivitis and one fatality [5,7].

On 19 February 2013, an 87 year-old man in Shanghai developed a respiratory infection and died on 4 March, and on 27 February 2013, a 27 year-old pork seller in a Shanghai market became ill and died on 10 March. A 35 year-old woman in Chuzhou City in Anhui province(west of Shanghai), who had contact with poultry, became ill on 15 March 2013, and remains hospitalised in critical condition. There is no known epidemiological relationship among these three cases. A 38 yearold man in Hangzhou(Zhejiang province, south of Shanghai)became ill on 7 March 2013 and died on 27 March. All four cases presented with respiratory infections that progressed to severe pneumonia and breathing difficulties.

On 31 March 2013, the Chinese Centre for Disease Control and Prevention announced the isolation in embryonated eggs of avian influenza viruses of the H7N9 subtype(designated A/Shanghai/1/2013, A/Shanghai/2/2013, and A/Anhui/1/2013)from the first three cases. The sequences of the coding regions of all eight viral genes were deposited in the influenza sequence database of the Global Initiative on Sharing All Influenza Data(GISAID)on 31 March(Table 1). On 5 April 2013, the Hangzhou Center for Disease Control and Prevention deposited the haemagglutinin(HA), neuraminidase(NA), and matrix(M)gene sequences of A/Hongzhou/1/2013 virus(Table 1), which was isolated in cell culture from samples obtained from the 38 yearold man.

All four human influenza A(H7N9)viruses are similar at the nucleotide and amino acid levels, suggesting a common ancestor. The HA gene of the novel viruses belongs to the Eurasian lineage of avian influenza viruses and shares ca. 95% identity with the HA genes of low pathogenic avian influenza A(H7N3)viruses isolated in 2011 in Zhejiang province(south of Shanghai)(Figure 1, Table 2). The NA gene of the novel viruses is ca. 96% identical to the low pathogenic avian influenza A(H11N9)viruses isolated in 2010 in the Czech Republic(Figure 1, Table 2).

Keywords: molecular-basis; british-columbia; H5N1 viruses; a virus; virulence; protein; pathogenicity; mice; conjunctivitis; glycosylation来源出版物: Eurosurveillance , 2013, 18(15): 7-21联系邮箱: Kageyama, T; mtashiro@nih.go.jp

被引频次: 94

10 x '20 Progress-Development of New Drugs Active Against Gram-Negative Bacilli: An Update From the Infectious Diseases Society of America

Boucher, HW; Talbot, GH; Benjamin, DK; et al.

Abstract: Infections caused by antibiotic-resistant bacteria, especially the "ESKAPE" pathogens, continue to increase in frequency and cause significant morbidity and mortality. New antimicrobial agents are greatly needed to treat infections caused by gram-negative bacilli(GNB)resistant to currently available agents. The Infectious Diseases Society of America(IDSA)continues to propose legislative, regulatory, and funding solutions to this continuing crisis. The current report updates the status of development and approval of systemic antibiotics in the United States as of early 2013. Only 2 new antibiotics have been approved since IDSA's 2009 pipeline status report, and the number of new antibiotics annually approved for marketing in the United States continues to decline. We identified 7 drugs in clinical development for treatment of infections caused by resistant GNB. None of these agents was included in our 2009 list of antibacterial com-pounds in phase 2 or later development, but unfortunately none addresses the entire spectrum of clinically relevant GNB resistance. Our survey demonstrates some progress in development of new antibacterial drugs that target infections caused by resistant GNB, but progress remains alarmingly elusive. IDSA stresses our conviction that the antibiotic pipeline problem can be solved by the collaboration of global leaders to develop creative incentives that will stimulate new antibacterial research and development. Our aim is the creation of a sustainable global antibacterial drug research and development enterprise with the power in the short term to develop 10 new, safe, and efficacious systemically administered antibiotics by 2020 as called for in IDSA's "10 x '20 Initiative."

Keywords: in-vitro activity; siderophore monosulfactam bal30072; acquired bacterial pneumonia; health-care epidemiology; pseudomonas-aeruginosa; clinical-trials; antimicrobial stewardship; acinetobacter-baumannii; antibacterial agents; beta-lactamases

来源出版物: Clinical Infectious Diseases , 2013, 56(12): 1685-1694联系邮箱: Guidos, RJ; rguidos@idsociety.org

被引频次: 94

Immunosuppression in sepsis: a novel understanding of the disorder and a new therapeutic approach

Hotchkiss, RS; Monneret, G; Payen, D

Abstract: Failures of highly touted trials have caused experts to call for re-evaluation of the current approach toward sepsis. New research has revealed key pathogenic mechanisms; autopsy results have shown that most patients admitted to intensive care units for treatment of sepsis had unresolved septic foci at post mortem, suggesting that patients were unable to eradicate invading pathogens and were more susceptible to nosocomial organisms, or both. These results suggest that therapies that improve host immunity might increase survival. Additional work showed that cytokine production by splenocytes taken post mortem from patients who died of sepsis is profoundly suppressed,possibly because of so-called T-cell exhaustion a newly recognised immunosuppressive mechanism that occurs with chronic antigenic stimulation. Results from two clinical trials of biomarker-guided therapeutic drugs that boosted immunity showed promising findings in sepsis. Collectively, these studies emphasise the degree of immunosuppression that occurs in sepsis, and explain why many previous sepsis trials which were directed at blocking inflammatory mediators or pathogen recognition signalling pathways failed. Finally, highly encouraging results from use of the new immunomodulatory molecules interleukin 7 and anti-programmed cell death 1 in infectious disease point the way for possible use in sepsis. We hypothesise that immunoadjuvant therapy represents the next major advance in sepsis.

Keywords: community-acquired pneumonia; randomized controlled-trial; intensive-care patients; multiple organ failure; improves survival;interferon-gamma; septic shock; immune dysfunctions; cytokine production; pd-1 expression

来源出版物: Lancet Infectious Diseases , 2013, 13(3): 260-268联系邮箱: Hotchkiss, RS; hotch@wustl.edu

INFORMATION SCIENCE LIBRARY SCIENCE 信息科学与图书馆学

被引频次: 29

Web-scale pharmacovigilance: listening to signals from the crowd

White, RW; Tatonetti, NP; Shah, NH; et al.

Abstract: Adverse drug events cause substantial morbidity and mortality and are often discovered after a drug comes to market. We hypothesized that Internet users may provide early clues about adverse drug events via their online information-seeking. We conducted a large-scale study of Web search log data gathered during 2010. We pay particular attention to the specific drug pairing of paroxetine and pravastatin, whose interaction was reported to cause hyperglycemia after the time period of the online logs used in the analysis. We also examine sets of drug pairs known to be associated with hyperglycemia and those not associated with hyperglycemia. We find that anonymized signals on drug interactions can be mined from search logs. Compared to analyses of other sources such as electronic health records(EHR), logs are inexpensive to collect and mine. The results demonstrate that logs of the search activities of populations of computer users can contribute to drug safety surveillance.

Keywords: adverse events; drug

来源出版物: Journal of The American Medical Informatics Association , 2013, 20(3): 404-408

联系邮箱: White, RW; ryenw@microsoft.com

被引频次: 29

Next-generation phenotyping of electronic health records

Hripcsak, G; Albers, DJ

Abstract: The national adoption of electronic health records(EHR)promises to make an unprecedented amount of data available for clinical research, but the data are complex, inaccurate, and frequently missing, and the record reflects complex processes aside from the patient's physiological state. We believe that the path forward requires studying the EHR as an object of interest in itself, and that new models,learning from data, and collaboration will lead to efficient use of the valuable information currently locked in health records.

Keywords: community-acquired pneumonia; medical-records; time-series; risk; classification; identification; information; databases; net-work; systems

来源出版物: Journal of The American Medical Informatics Association , 2013, 20(1): 117-121

联系邮箱: Hripcsak, G; hripcsak@columbia.edu

被引频次: 27

Methods and dimensions of electronic health record data quality assessment: enabling reuse for clinical research

Weiskopf, NG; Weng, CH

Abstract: Objective To review the methods and dimensions of data quality assessment in the context of electronic health record(EHR)data reuse for research.

Materials and methods A review of the clinical research literature discussing data quality assessment methodology for EHR data was performed. Using an iterative process, the aspects of data quality being measured were abstracted and categorized, as well as the methods of assessment used.

Results Five dimensions of data quality were identified, which are completeness, correctness, concordance, plausibility, and currency, and seven broad categories of data quality assessment methods: comparison with gold standards, data element agreement, data source agreement, distribution comparison, validity checks, log review, and element presence.

Discussion Examination of the methods by which clinical researchers have investigated the quality and suitability of EHR data for research shows that there are fundamental features of data quality, which may be difficult to measure, as well as proxy dimensions. Researchers interested in the reuse of EHR data for clinical research are recommended to consider the adoption of a consistent taxonomy of EHR data quality, to remain aware of the task-dependence of data quality, to integrate work on data quality assessment from other fields, and to adopt systematic, empirically driven, statistically based methods of data quality assessment.

Conclusion There is currently little consistency or potential generalizability in the methods used to assess EHR data quality. If the reuse of EHR data for clinical research is to become accepted, researchers should adopt validated, systematic methods of EHR data quality assessment.

Keywords: manchester orthopedic database; computerized medical-records; ischemic-heart-disease; general-practice data; end-digit preference; primary-care data; patient records; improvement network; administrative data; united-kingdom

来源出版物: Journal of The American Medical Informatics Association , 2013, 20(1): 144-151

联系邮箱: Weiskopf, NG; nicole.weiskopf@dbmi.columbia.edu

被引频次: 23

Reduction in medication errors in hospitals due to adoption of computerized provider order entry systems

Radley, DC; Wasserman, MR; Olsho, LEW; et al.

Abstract: Objective Medication errors in hospitals are common, expensive, and sometimes harmful to patients. This study's objective was to derive a nationally representative estimate of medication error reduction in hospitals attributable to electronic prescribing through computerized provider order entry(CPOE)systems.

Materials and methods We conducted a systematic literature review and applied random-effects meta-analytic techniques to derive a summary estimate of the effect of CPOE on medication errors. This pooled estimate was combined with data from the 2006 American Society of Health-System Pharmacists Annual Survey, the 2007 American Hospital Association Annual Survey, and the latter's 2008 Electronic Health Record Adoption Database supplement to estimate the percentage and absolute reduction in medication errors attributable to CPOE. Results Processing a prescription drug order through a CPOE system decreases the likelihood of error on that order by 48%(95% CI 41% to 55%). Given this effect size, and the degree of CPOE adoption and use in hospitals in 2008, we estimate a 12.5% reduction in medication errors, or similar to 17.4 million medication errors averted in the USA in 1 year.

Discussion Our findings suggest that CPOE can substantially reduce the frequency of medication errors in inpatient acute-care settings;however, it is unclear whether this translates into reduced harm for patients.

Conclusions Despite CPOE systems' effectiveness at preventing medication errors, adoption and use in US hospitals remain modest. Current policies to increase CPOE adoption and use will likely prevent millions of additional medication errors each year. Further research is needed to better characterize links to patient harm.

Keywords: adverse drug events; prevention; consequences; safety; impact

来源出版物: Journal of The American Medical Informatics Association , 2013, 20(3): 470-476

联系邮箱: Olsho, LEW; lauren_olsho@abtassoc.com

被引频次: 18

Enhancing patient safety and quality of care by improving the usability of electronic health record systems: recommendations from AMIA

Middleton, B; Bloomrosen, M; Dente, MA; et al.

Abstract: In response to mounting evidence that use of electronic medical record systems may cause unintended consequences, and even patient harm, the AMIA Board of Directors convened a Task Force on Usability to examine evidence from the literature and make recommendations. This task force was composed of representatives from both academic settings and vendors of electronic health record(EHR)systems. After a careful review of the literature and of vendor experiences with EHR design and implementation, the task force developed 10 recommendations in four areas:(1)human factors health information technology(IT)research,(2)health IT policy,(3)industry recommendations, and(4)recommendations for the clinician end-user of EHR software. These AMIA recommendations are intended to stimulate informed debate, provide a plan to increase understanding of the impact of usability on the effective use of health IT, and lead to safer and higher quality care with the adoption of useful and usable EHR systems.

Keywords: physician order entry; clinical information-systems; unintended consequences; ambulatory-care; technology; alerts; impact;performance; design; errors

来源出版物: Journal of The American Medical Informatics Association , 2013, 20(E1): E2-E8

联系邮箱: Middleton, B; bmiddleton1@partners.org

INSTRUMENTS INSTRUMENTATION 仪器与仪器仪表

被引频次: 103

Real-Time Implementation of Fault-Tolerant Control Systems With Performance Optimization

Yin, S; Luo, H; Ding, SX

Abstract: In this paper, two online schemes for an integrated design of fault-tolerant control(FTC)systems with application to Tennessee Eastman(TE)benchmark are proposed. Based on the data-driven design of the proposed fault-tolerant architecture whose core is an observer/residual generator based realization of the Youla parameterization of all stabilization controllers, FTC is achieved by an adaptive residual generator for the online identification of the fault diagnosis relevant vectors, and an iterative optimization method for system performance enhancement. The performance and effectiveness of the proposed schemes are demonstrated through the TE benchmark model.

Keywords: diagnosis; drives; identification; strategies; design

来源出版物: IEEE Transactions on Industrial Electronics , 2014, 61(5): 2402-2411联系邮箱: Yin, S; shen.yin2011@googlemail.com

被引频次: 98

The LHCb trigger and its performance in 2011

Aaij, R; Albrecht, J; Alessio, F; et al.

Abstract: This paper presents the design of the LHCb trigger and its performance on data taken at the LHC in 2011. A principal goal of LHCb is to perform flavour physics measurements, and the trigger is designed to distinguish charm and beauty decays from the light quark background. Using a combination of lepton identification and measurements of the particles' transverse momenta the trigger selects particles originating from charm and beauty hadrons, which typically fly a finite distance before decaying. The trigger reduces the roughly 11 MHz of bunch-bunch crossings that contain at least one inelastic pp interaction to 3 kHz. This reduction takes place in two stages; the first stage is implemented in hardware and the second stage is a software application that runs on a large computer farm. A data-driven method is used to evaluate the performance of the trigger on several charm and beauty decay modes.

来源出版物: Journal of Instrumentation , 2013, 8: P04022联系邮箱: Dijkstra, H; Hans.Dijkstra@cern.ch

被引频次: 79

Adaptive Sliding-Mode Control for Nonlinear Active Suspension Vehicle Systems Using T-S Fuzzy Approach

Li, HY; Yu, JY; Hilton, C; et al.

Abstract: This paper deals with the adaptive sliding-mode control problem for nonlinear active suspension systems via the Takagi-Sugeno(T-S)fuzzy approach. The varying sprung and unsprung masses, the unknown actuator nonlinearity, and the suspension performances are taken into account simultaneously, and the corresponding mathematical model is established. The T-S fuzzy system is used to describe the original nonlinear system for the control-design aim via the sector nonlinearity approach. A sufficient condition is proposed for the asymptotical stability of the designing sliding motion. An adaptive sliding-mode controller is designed to guarantee the reachability of the specified switching surface. The condition can be converted to the convex optimization problems. Simulation results for a half-vehicle active suspension model are provided to demonstrate the effectiveness of the proposed control schemes.

Keywords: h-infinity control; time-delay; car model; feedback; design

来源出版物: IEEE Transactions on Industrial Electronics , 2013, 60(8): 3328-3338联系邮箱: Li, HY; lihongyi2009@gmail.com

被引频次: 67

Coupled-least-squares identification for multivariable systems

Ding, F

Abstract: This article studies identification problems of multiple linear regression models, which may be described a class of multi-input multi-output systems(i.e. multivariable systems). Based on the coupling identification concept, a novel coupled-least-squares(C-LS)parameter identification algorithm is introduced for the purpose of avoiding the matrix inversion in the multivariable recursive least-squares(RLS)algorithm for estimating the parameters of the multiple linear regression models. The analysis indicates that the C-LS algorithm does not involve the matrix inversion and requires less computationally efforts than the multivariable RLS algorithm, and that the parameter estimates given by the C-LS algorithm converge to their true values. Simulation results confirm the presented convergence theorems.

Keywords: stochastic regression-models; moving average systems; state-space models; dual-rate systems; parameter-estimation; adaptive prediction; auxiliary model; performance analysis; estimation algorithm; sampled-data

来源出版物: IET Control Theory and Applications , 2013, 7(1): 68-79联系邮箱: Ding, F; fding@jiangnan.edu.cn

被引频次: 59

Distributed H-infinity Filtering for a Class of Markovian Jump Nonlinear Time-Delay Systems Over Lossy Sensor Networks

Dong, HL; Wang, ZD; Gao, HJ

Abstract: This paper is concerned with the distributed H-infinity filtering problem for a class of discrete-time Markovian jump nonlinear time-delay systems with deficient statistics of mode transitions. The system measurements are collected through a lossy sensor network subject to randomly occurring quantization errors and randomly occurring packet dropouts. The description of deficient statistics of mode transitions that account for known, unknown, and uncertain transition probabilities is comprehensive. A distributed filter design scheme is outlined by explicitly characterizing the filter gains in terms of some matrix inequalities. Simulation results demonstrate the effectiveness of the proposed filtering scheme.

Keywords: missing measurements; wireless sensor; stochastic-systems; actuator networks; probabilities

来源出版物: IEEE Transactions on Industrial Electronics , 2013, 60(10): 4665-4672联系邮箱: Dong, HL; shiningdhl@gmail.com

INTEGRATIVE COMPLEMENTARY MEDICINE 中西医结合与补充医学

被引频次: 19

Network pharmacology-based prediction of the active ingredients and potential targets of Chinese herbal Radix Curcumae formula for application to cardiovascular disease

Tao, WY; Xu, X; Wang, X; et al.

Abstract: Ethnopharmacology relevance: Cardiovascular and cerebrovascular diseases(CCVD), an abnormal function of the heart, brain or blood vessels, are the biggest cause of deaths worldwide. Traditional Chinese medicine(TCM)holds a great promise for preventing such diseases in an integrative and holistic way. However, its systems-level characterization of drug-target associations is still unknown. Methods: Here, we have constructed a computational approach by combining chemical predictors based on chemical structure, chemogenomics data linking compounds with pharmacological information, and a system biology functional data analysis and network reconstruction method. Results: The pharmacological system generated 58 bioactive ingredients from the Chinese herbal Radix Curcumae formula, and predicted 32 potential targets related to the CCVD. The results indicates that Radix Curcumae share the most common targets with Fructus Gardeniae(15), while less common targets with Moschus and Borneolum(8 and 1, respectively). Further integrated network shows that Radix Curcumae represents the principal component for the prevention of CCVD, and other three medicines serve as adjuvant ones to assist the effects of the principal component, which together probably display synergistic actions. Conclusions: Our work successfully explains the mechanism of efficiency of Radix Curcumae formula for the prevention of CCVD, and meanwhile, predicts the potential targets of the Chinese medicines, which facilitates to elucidate the compatible mechanism of the complex prescription, i.e., "jun-chen-zuo-shi", and provides basis for an alternative approach to investigate novel TCM formula on the network pharmacology level.

Keywords: medicine; metabolism; rats; pharmacokinetics; bioavailability; hypertension; absorption; docking; step; tcm

来源出版物: Journal of Ethnopharmacology , 2013, 145(1): 1-10联系邮箱: Wang, YH; yh_wang@nwsuaf.edu.cn

被引频次: 16

Hesperidin attenuates cisplatin-induced acute renal injury by decreasing oxidative stress,inflammation and DNA damage

Sahu, BD; Kuncha, M; Sindhura, GJ; et al.

Abstract: Nephrotoxicity is an important complication in cancer patients undergoing cisplatin therapy. Oxidative stress, inflammation andapoptosis/necrosis are the major patho-mechanisms of cisplatin induced nephrotoxicity. In the present study, hesperidin, a naturally-occurring bioflavonoid has been demonstrated to have protective effect on cisplatin-induced renal injury in rats. Cisplatin intoxication resulted in structural and functional renal impairment which was revealed by massive histopathological changes and elevated blood urea nitrogen and serum creatinine levels, respectively. Renal injury was associated with oxidative stress/lipid peroxidation as evident by increased reactive oxygen species(ROS)and malondialdehyde(MDA)formation with decreased levels of antioxidants such as reduced glutathione, vitamin C, catalase, superoxide dismutase, glutathione reductase, glutathione peroxidase and glutathione-S-transferase. Cisplatin administration also triggered inflammatory response in rat kidneys by inducing pro-inflammatory cytokine, TNF-alpha, with the increased expression of myeloperoxidase(MPO). Furthermore, cisplatin increased the activity of caspase-3 and DNA damage with decreased tissue nitric oxide levels. Hesperidin treatment significantly attenuated the cisplatin-induced oxidative stress/lipid peroxidation, inflammation(infiltration of leukocytes and pro-inflammatory cytokine), apoptosis/necrosis(caspase-3 activity with DNA damage)as well as increased expression of nitric oxide in the kidney and improved renal function. Thus, our results suggest that hesperidin co-administration may serve as a novel and promising preventive strategy against cisplatin-induced nephrotoxicity.

Keywords: nephrotoxicity; acid; apoptosis; rats; antioxidant; mechanisms; toxicity; tissues; kidney; alpha

来源出版物: Phytomedicine , 2013, 20(5): 453-460联系邮箱: Sistla, R; sistla@iict.res.in

被引频次: 14

CamMedNP: Building the Cameroonian 3D structural natural products database for virtual screening

Ntie-Kang, F; Mbah, JA; Mbaze, LM; et al.

Abstract: Background: Computer-aided drug design(CADD)often involves virtual screening(VS)of large compound datasets and the availability of such is vital for drug discovery protocols. We present CamMedNP - a new database beginning with more than 2500 compounds of natural origin, along with some of their derivatives which were obtained through hemisynthesis. These are pure compounds which have been previously isolated and characterized using modern spectroscopic methods and published by several research teams spread across Cameroon. Description: In the present study, 224 distinct medicinal plant species belonging to 55 plant families from the Cameroonian flora have been considered. About 80 % of these have been previously published and/or referenced in internationally recognized journals. For each compound, the optimized 3D structure, drug-like properties, plant source, collection site and currently known biological activities are given, as well as literature references. We have evaluated the "drug-likeness" of this database using Lipinski's "Rule of Five". A diversity analysis has been carried out in comparison with the ChemBridge diverse database.

Conclusion: CamMedNP could be highly useful for database screening and natural product lead generation programs.

Keywords: drug discovery; plants

来源出版物: Bmc Complementary and Alternative Medicine , 2013, 13: 88联系邮箱: Ntie-Kang, F; ntiekfidele@gmail.com

被引频次: 14

Clinical Utility of Curcumin Extract

Asher, GN; Spelman, K

Abstract: Turmeric root has been used medicinally in China and India for thousands of years. The active components are thought to be the curcuminoids, primarily curcumin, which is commonly available worldwide as a standardized extract. This article reviews the pharmacology of curcuminoids, their use and efficacy, potential adverse effects, and dosage and standardization. Preclinical studies point to mechanisms of action that are predominantly anti-inflammatory and antineoplastic, while early human clinical trials suggest beneficial effects for dyspepsia, peptic ulcer, inflammatory bowel disease, rheumatoid arthritis, osteoarthritis, uveitis, orbital pseudotumor, and pancreatic cancer. Curcumin is well-tolerated; the most common side effects are nausea and diarrhea. Theoretical interactions exist due to purported effects on metabolic enzymes and transport proteins, but clinical reports do not support any meaningful interactions. Nonetheless, caution, especially with chemotherapy agents, is advised. Late-phase clinical trials are still needed to confirm most beneficial effects.

Keywords: trial; products; medicine; disease; cancer

来源出版物: Alternative Therapies in Health and Medicine , 2013, 19(2): 20-22联系邮箱: Asher, GN; gasher@med.unc.edu

被引频次: 14

Traditional Chinese medicine network pharmacology: theory, methodology and application

Li, S; Zhang, B

Abstract: Traditional Chinese medicine(TCM)has a long history of viewing an individual or patient as a system with different statuses,and has accumulated numerous herbal formulae. The holistic philosophy of TCM shares much with the key ideas of emerging network pharmacology and network biology, and meets the requirements of overcoming complex diseases, such as cancer, in a systematic manner. To discover TCM from a systems perspective and at the molecular level, a novel TCM network pharmacology approach was established by updating the research paradigm from the current "one target, one drug" mode to a new "network target, multi-components" mode. Subse-quently, a set of TCM network pharmacology methods were created to prioritize, disease-associated genes, to predict the target profiles and pharmacological actions of herbal compounds, to reveal drug-gene-disease co-module associations, to screen synergistic multi-compounds from herbal formulae in a high-throughput manner, and to interpret the combinatorial rules and network regulation effects of herbal formulae. The effectiveness of the network-based methods was demonstrated for the discovery of bioactive compounds and for the elucidation of the mechanisms of action of herbal formulae, such as Qing-Luo-Yin and the Liu-Wei-Di-Huang pill. The studies suggest that the TCM network pharmacology approach provides a new research paradigm for translating TCM from an experience-based medicine to an evidence-based medicine system, which will accelerate TCM drug discovery, and also improve current drug discovery strategies.

Keywords: vascular endothelial-cells; molecular networks; drug-combinations; disease genes; tnf-alpha; database; systems; formula; angiogenesis; prediction

来源出版物: Chinese Journal of Natural Medicines , 2013, 11(2): 110-120联系邮箱: Li, S; shaoli@mail.tsinghua.edu.cn

LIMNOLOGY 湖沼学

被引频次: 29

The Millennium Drought in southeast Australia(2001-2009): Natural and human causes and implications for water resources, ecosystems, economy, and society

van Dijk, AIJM; Beck, HE; Crosbie, RS; et al.

Abstract: The "Millennium Drought"(2001-2009)can be described as the worst drought on record for southeast Australia. Adaptation to future severe droughts requires insight into the drivers of the drought and its impacts. These were analyzed using climate, water, economic,and remote sensing data combined with biophysical modeling. Prevailing El Nino conditions explained about two thirds of rainfall deficit in east Australia. Results for south Australia were inconclusive; a contribution from global climate change remains plausible but unproven. Natural processes changed the timing and magnitude of soil moisture, streamflow, and groundwater deficits by up to several years, and caused the amplification of rainfall declines in streamflow to be greater than in normal dry years. By design, river management avoided impacts on some categories of water users, but did so by exacerbating the impacts on annual irrigation agriculture and, in particular, river ecosystems. Relative rainfall reductions were amplified 1.5-1.7 times in dryland wheat yields, but the impact was offset by steady increases in cropping area and crop water use efficiency(perhaps partly due to CO2fertilization). Impacts beyond the agricultural sector occurred(e.g., forestry, tourism, utilities)but were often diffuse and not well quantified. Key causative pathways from physical drought to the degradation of ecological, economic, and social health remain poorly understood and quantified. Combined with the multiple dimensions of multiyear droughts and the specter of climate change, this means future droughts may well break records in ever new ways and not necessarily be managed better than past ones.

Keywords: annular mode; eastern australia; climate-change; rainfall variability; soil-moisture; ndvi data; evapotranspiration; dataset; systems; trends

来源出版物: Water Resources Research , 2013, 49(2): 1040-1057联系邮箱: van Dijk, AIJM; albert.vandijk@anu.edu.au

被引频次: 27

Generation, transport, and disposal of wastewater associated with Marcellus Shale gas development

Lutz, BD; Lewis, AN; Doyle, MW

Abstract: Hydraulic fracturing has made vast quantities of natural gas from shale available, reshaping the energy landscape of the United States. Extracting shale gas, however, generates large, unavoidable volumes of wastewater, which to date lacks accurate quantification. For the Marcellus shale, by far the largest shale gas resource in the United States, we quantify gas and wastewater production using data from 2189 wells located throughout Pennsylvania. Contrary to current perceptions, Marcellus wells produce significantly less wastewater per unit gas recovered(approximately 35%)compared to conventional natural gas wells. Further, well operators classified only 32.3% of wastewater from Marcellus wells as flowback from hydraulic fracturing; most wastewater was classified as brine, generated over multiple years. Despite producing less wastewater per unit gas, developing the Marcellus shale has increased the total wastewater generated in the region by approximately 570% since 2004, overwhelming current wastewater disposal infrastructure capacity.

Keywords: natural-gas; pennsylvania; challenges; methane; brine

来源出版物: Water Resources Research , 2013, 49(2): 647-656联系邮箱: Lutz, BD; blutz6@kent.edu

被引频次: 25

Macropores and water flow in soils revisited

Beven, K; Germann, P

Abstract: The original review of macropores and water flow in soils by Beven and Germann is now 30 years old and has become one of the most highly cited papers in hydrology. This paper attempts to review the progress in observations and theoretical reasoning about pre-ferential soil water flows over the intervening period. It is suggested that the topic has still not received the attention that its importance deserves, in part because of the ready availability of software packages rooted firmly in the Richards domain, albeit that there is convincing evidence that this may be predicated on the wrong experimental method for natural conditions. There is still not an adequate physical theory linking all types of flow, and there are still not adequate observational techniques to support the scale dependent parameterizations that will be required at practical field and hillslope scales of application. Some thoughts on future needs to develop a more comprehensive representation of soil water flows are offered.

Keywords: electrical-resistivity tomography; kinematic wave approximation; lateral preferential flow; hydrologic-response simulation;hillslope threshold response; multiple anionic tracers; unsaturated porous-media; physically-based model; subsurface storm flow;dual-porosity model

来源出版物: Water Resources Research , 2013, 49(6): 3071-3092联系邮箱: Beven, K; K.Beven@lancaster.ac.uk

被引频次: 24

The responses of eight coral reef calcifiers to increasing partial pressure of CO2 do not exhibit a tipping point

Comeau, S; Edmunds, PJ; Spindel, NB; et al.

Abstract: The objective of this study was to investigate whether a tipping point exists in the calcification responses of coral reef calcifiers to CO2. We compared the effects of six partial pressures of CO2(P-CO2)from 28 Pa to 210 Pa on the net calcification of four corals(Acropora pulchra, Porites rus, Pocillopora damicornis, and Pavona cactus), and four calcified algae(Hydrolithon onkodes, Lithophyllum flavescens, Halimeda macroloba, and Halimeda minima). After 2 weeks of acclimation in a common environment, organisms were incubated in 12 aquaria for 2 weeks at the targeted P-CO2levels and net calcification was quantified. All eight species calcified at the highest P-CO2in which the calcium carbonate aragonite saturation state was similar to 1. Calcification decreased linearly as a function of increasing partial P-CO2in three corals and three algae. Overall, the decrease in net calcification as a function of decreasing pH was similar to 10% when ambient P-CO2(39 Pa)was doubled. The calcification responses of P. damicornis and H. macroloba were unaffected by increasing P-CO2. These results are inconsistent with the notion that coral reefs will be affected by rising P-CO2in a response characterized by a tipping point. Instead,our findings combined among taxa suggest a gradual decline in calcification will occur, but this general response includes specific cases of complete resistance to rising P-CO2. Together our results suggest that the overall response of coral reef communities to ocean acidification will be monotonic and inversely proportional to P-CO2, with reef-wide responses dependent on the species composition of calcifying taxa.

Keywords: ocean acidification; climate-change; calcification; algae; productivity; temperature; halimeda

来源出版物: Limnology and Oceanography , 2013, 58(1): 388-398联系邮箱: Comeau, S; steve.comeau@csun.edu

被引频次: 23

Groundwater depletion in the Middle East from GRACE with implications for transboundary water management in the Tigris-Euphrates-Western Iran region

Voss, KA; Famiglietti, JS; Lo, MH; et al.

Abstract: In this study, we use observations from the Gravity Recovery and Climate Experiment(GRACE)satellite mission to evaluate freshwater storage trends in the north-central Middle East, including portions of the Tigris and Euphrates River Basins and western Iran,from January 2003 to December 2009. GRACE data show an alarming rate of decrease in total water storage of approximately -27.2± 0.6 mm yr(-1)equivalent water height, equal to a volume of 143.6 km3during the course of the study period. Additional remote-sensing information and output from land surface models were used to identify that groundwater losses are the major source of this trend. The approach used in this study provides an example of "best current capabilities" in regions like the Middle East, where data access can be severely limited. Results indicate that the region lost 17.3±2.1 mm yr(-1)equivalent water height of groundwater during the study period, or 91.3±10.9 km3in volume. Furthermore, results raise important issues regarding water use in transboundary river basins and aquifers, including the necessity of international water use treaties and resolving discrepancies in international water law, while amplifying the need for increased monitoring for core components of the water budget.

Keywords: climate experiment grace; time-variable gravity; satellite-observations; canadian prairie; model; storage; system; precipitation;assimilation; variability

来源出版物: Water Resources Research , 2013, 49(2): 904-914联系邮箱: Famiglietti, JS; jfamigli@uci.edu

MARINE FRESHWATER BIOLOGY 海洋与淡水生物学

被引频次: 40

Long-term and trans-life-cycle effects of exposure to ocean acidification in the green sea urchin Strongylocentrotus droebachiensis

Dupont, S; Dorey, N; Stumpp, M; et al.

Abstract: Anthropogenic CO2emissions are acidifying the world's oceans. A growing body of evidence demonstrates that ocean acidifica-tion can impact survival, growth, development and physiology of marine invertebrates. Here, we tested the impact of long-term(up to 16 months)and trans-life-cycle(adult, embryo/larvae and juvenile)exposure to elevated pCO2(1200 mu atm, compared to control 400 mu atm)on the green sea urchin Strongylocentrotus droebachiensis. Female fecundity was decreased 4.5-fold when acclimated to elevated pCO2for 4 months during reproductive conditioning, while no difference was observed in females acclimated for 16 months. Moreover, adult pre-exposure for 4 months to elevated pCO2had a direct negative impact on subsequent larval settlement success. Five to nine times fewer offspring reached the juvenile stage in cultures using gametes collected from adults previously acclimated to high pCO2for 4 months. However, no difference in larval survival was observed when adults were pre-exposed for 16 months to elevated pCO2. pCO2had no direct negative impact on juvenile survival except when both larvae and juveniles were raised in elevated pCO2. These negative effects on settlement success and juvenile survival can be attributed to carry-over effects from adults to larvae and from larvae to juveniles. Our results support the contention that adult sea urchins can acclimate to moderately elevated pCO2in a matter of a few months and that carry-over effects can exacerbate the negative impact of ocean acidification on larvae and juveniles.

Keywords: resource-allocation; food limitation; carbonic-acid; growth-rate; high CO2; seawater; larvae; plasticity; survival; metamorphosis

来源出版物: Marine Biology , 2013, 160(8): 1835-1843联系邮箱: Dupont, S; sam.dupont@bioenv.gu.se

被引频次: 35

Is Ocean Acidification an Open-Ocean Syndrome? Understanding Anthropogenic Impacts on Seawater pH

Duarte, CM; Hendriks, IE; Moore, TS; et al.

Abstract: Ocean acidification due to anthropogenic CO2emissions is a dominant driver of long-term changes in pH in the open ocean,raising concern for the future of calcifying organisms, many of which are present in coastal habitats. However, changes in pH in coastal ecosystems result from a multitude of drivers, including impacts from watershed processes, nutrient inputs, and changes in ecosystem structure and metabolism. Interaction between ocean acidification due to anthropogenic CO2emissions and the dynamic regional to local drivers of coastal ecosystems have resulted in complex regulation of pH in coastal waters. Changes in the watershed can, for example, lead to changes in alkalinity and CO2fluxes that, together with metabolic processes and oceanic dynamics, yield high-magnitude decadal changes of up to 0.5 units in coastal pH. Metabolism results in strong diel to seasonal fluctuations in pH, with characteristic ranges of 0.3 pH units, with metabolically intense habitats exceeding this range on a daily basis. The intense variability and multiple, complex controls on pH implies that the concept of ocean acidification due to anthropogenic CO2emissions cannot be transposed to coastal ecosystems directly. Furthermore, in coastal ecosystems, the detection of trends towards acidification is not trivial and the attribution of these changes to anthropogenic CO2emissions is even more problematic. Coastal ecosystems may show acidification or basification, depending on the balance between the invasion of coastal waters by anthropogenic CO2, watershed export of alkalinity, organic matter and CO2, and changes in the balance between primary production, respiration and calcification rates in response to changes in nutrient inputs and losses of ecosystem components. Hence, we contend that ocean acidification from anthropogenic CO2is largely an open-ocean syndrome and that a concept of anthropogenic impacts on marine pH, which is applicable across the entire ocean, from coastal to open-ocean environments, provides a superior framework to consider the multiple components of the anthropogenic perturbation of marine pH trajectories. The concept of anthropogenic impacts on seawater pH acknowledges that a regional focus is necessary to predict future trajectories in the pH of coastal waters and points at opportunities to manage these trajectories locally to conserve coastal organisms vulnerable to ocean acidification.

Keywords: acid sulfate soil; carbon-dioxide concentrations; long-term changes; water-quality; coastal zone; seagrass photosynthesis; atmospheric CO2; global carbon; mine drainage; coral-reefs

来源出版物: Estuaries and Coasts , 2013, 36(2): 221-236联系邮箱: Duarte, CM; carlosduarte@ifisc.uib.es

被引频次: 32

The World Ocean Silica Cycle

Treguer, PJ; De La Rocha, CL

Abstract: Over the past few decades, we have realized that the silica cycle is strongly intertwined with other major biogeochemical cycles,like those of carbon and nitrogen, and as such is intimately related to marine primary production, the efficiency of carbon export to the deep sea, and the inventory of carbon dioxide in the atmosphere. For nearly 20 years, the marine silica budget compiled by Treguer et al.(1995),with its exploration of reservoirs, processes, sources, and sinks in the silica cycle, has provided context and information fundamental to study of the silica cycle. Today, the budget needs revisiting to incorporate advances that have notably changed estimates of river and groundwater inputs to the ocean of dissolved silicon and easily dissolvable amorphous silica, inputs from the dissolution of terrestrial lithogenic silica in ocean margin sediments, reverse weathering removal fluxes, and outputs of biogenic silica(especially on ocean margins and in the form of nondiatomaceous biogenic silica). The resulting budget recognizes significantly higher input and output fluxes and notes that the recycling of silicon occurs mostly at the sediment-water interface and not during the sinking of silica particles through deep waters.

Keywords: submarine groundwater discharge; equatorial pacific-ocean; regulate si uptake; missing ge sink; biogenic silica; southern-ocean;organic-carbon; north pacific; time-series; phytoplankton productivity

来源出版物: Annual Review of Marine Science, 2013, 5: 477-501联系邮箱: Treguer, PJ; paul.treguer@univ-brest.fr

被引频次: 31

Misuse of the phytoplanktonzooplankton dichotomy: the need to assign organisms as mixotrophs within plankton functional types

Flynn, KJ; Stoecker, DK; Mitra, A; et al.

Abstract: The classic portrayal of plankton is dominated by phytoplanktonic primary producers and zooplanktonic secondary producers. In reality, many if not most plankton traditionally labelled as phytoplankton or microzooplankton should be identified as mixotrophs, contributing to both primary and secondary production. Mixotrophic protists(i.e. single-celled eukaryotes that perform photosynthesis and graze on particles)do not represent a minor component of the plankton, as some form of inferior representatives of the past evolution of protists;they represent a major component of the extant protist plankton, and one which could become more dominant with climate change. The implications for this mistaken identification, of the incorrect labelling of mixotrophs as phytoplankton or microzooplankton, are great. It extends from the(mis)use of photopigments as indicators of primary production performed by strict photoautotrophs rather than also(co)locating mixotrophic activity, through to the inadequacy of plankton functional type descriptions in models(noting that mixotrophic production in the individual organism is not a simple sum of phototrophy and heterotrophy). We propose that mixotrophy should be recognized as a major contributor to plankton dynamics, with due effort expended in field and laboratory studies, and should no longer be side-lined in conceptual food webs or in mathematical models.

Keywords: red-tide; cyanobacterium synechococcus; dinophysis-caudata; marine ecosystems; bloom dynamics; growth; carbon; photosynthesis; protists; nitrogen

来源出版物: Journal of Plankton Research , 2013, 35(1): 3-11联系邮箱: Flynn, KJ; k.j.flynn@swansea.ac.uk

被引频次: 26

The Global Distribution and Dynamics of Chromophoric Dissolved Organic Matter

Nelson, NB; Siegel, DA

Abstract: Chromophoric dissolved organic matter(CDOM)is a ubiquitous component of the open ocean dissolved matter pool, and is important owing to its influence on the optical properties of the water column, its role in photochemistry and photobiology, and its utility as a tracer of deep ocean biogeochemical processes and circulation. In this review, we discuss the global distribution and dynamics of CDOM in the ocean, concentrating on developments in the past 10 years and restricting our discussion to open ocean and deep ocean(below the main thermocline)environments. CDOM has been demonstrated to exert primary control on ocean color by its absorption of light energy,which matches or exceeds that of phytoplankton pigments in most cases. This has important implications for assessing the ocean biosphere via ocean color-based remote sensing and the evaluation of ocean photochemical and photobiological processes. The general distribution of CDOM in the global ocean is controlled by a balance between production(primarily microbial remineralization of organic matter)and photolysis, with vertical ventilation circulation playing an important role in transporting CDOM to and from intermediate water masses. Significant decadal-scale fluctuations in the abundance of global surface ocean CDOM have been observed using remote sensing, indicating a potentially important role for CDOM in ocean-climate connections through its impact on photochemistry and photobiology.

Keywords: mississippi river plume; middle atlantic bight; sargasso sea; ocean color; optical-properties; absorption-coefficients; in-situ;light-absorption; north-atlantic; pacific-ocean

来源出版物: Annual Review of Marine Science, 2013, 5: 447-476联系邮箱: Nelson, NB; norm@eri.ucsb.edu

MATERIALS SCIENCE BIOMATERIALS 生物材料学

被引频次: 130

Review of bioactive glass: From Hench to hybrids

Jones, JR

Abstract: Bioactive glasses are reported to be able to stimulate more bone regeneration than other bioactive ceramics but they lag behind other bioactive ceramics in terms of commercial success. Bioactive glass has not yet reached its potential but research activity is growing. This paper reviews the current state of the art, starting with current products and moving onto recent developments. Larry Hench's 4555 Bioglass(R)was the first artificial material that was found to form a chemical bond with bone, launching the field of bioactive ceramics. In vivo studies have shown that bioactive glasses bond with bone more rapidly than other bioceramics, and in vitro studies indicate that their osteogenic properties are due to their dissolution products stimulating osteoprogenitor cells at the genetic level. However, calcium phosphates such as tricalcium phosphate and synthetic hydroxyapatite are more widely used in the clinic. Some of the reasons are commercial,but others are due to the scientific limitations of the original Bioglass 45S5. An example is that it is difficult to produce porous bioactiveglass templates(scaffolds)for bone regeneration from Bioglass 45S5 because it crystallizes during sintering. Recently, this has been overcome by understanding how the glass composition can be tailored to prevent crystallization. The sintering problems can also be avoided by synthesizing sol-gel glass, where the silica network is assembled at room temperature. Process developments in foaming, solid freeform fabrication and nanofibre spinning have now allowed the production of porous bioactive glass scaffolds from both melt- and sol-gel-derived glasses. An ideal scaffold for bone regeneration would share load with bone. Bioceramics cannot do this when the bone defect is subjected to cyclic loads, as they are brittle. To overcome this, bioactive glass polymer hybrids are being synthesized that have the potential to be tough, with congruent degradation of the bioactive inorganic and the polymer components. Key to this is creating nanoscale interpenetrating networks, the organic and inorganic components of which have covalent coupling between them, which involves careful control of the chemistry of the sol-gel process. Bioactive nanoparticles can also now be synthesized and their fate tracked as they are internalized in cells. This paper reviews the main developments in the field of bioactive glass and its variants, covering the importance of control of hierarchical structure, synthesis, processing and cellular response in the quest for new regenerative synthetic bone grafts. The paper takes the reader from Hench's Bioglass 45S5 to new hybrid materials that have tailorable mechanical properties and degradation rates.

Keywords: cells in-vitro; bone-graft substitutes; sol-gel method; intrabony periodontal defects; camphene-based suspensions; angiogenic growth-factors; tibial plateau fractures; mesenchymal stem-cells; melt-derived 45S5; x-ray-diffraction

来源出版物: Acta Biomaterialia , 2013, 9(1): 4457-4486联系邮箱: Jones, JR; julian.r.jones@imperial.ac.uk

被引频次: 90

Dual and multi-stimuli responsive polymeric nanoparticles for programmed site-specific drug delivery

Cheng, R; Meng, FH; Deng, C; et al.

Abstract: In the past decades, polymeric nanoparticles have emerged as a most promising and viable technology platform for targeted and controlled drug delivery. As vehicles, ideal nanoparticles are obliged to possess high drug loading levels, deliver drug to the specific pathological site and/or target cells without drug leakage on the way, while rapidly unload drug at the site of action. To this end, various "intelligent" polymeric nanoparticles that release drugs in response to an internal or external stimulus such as pH, redox, temperature, magnetic and light have been actively pursued. These stimuli-responsive nanoparticles have demonstrated, though to varying degrees, improved in vitro and/or in vivo drug release profiles. In an effort to further improve drug release performances, novel dual and multi-stimuli responsive polymeric nanoparticles that respond to a combination of two or more signals such as pH/temperature, pH/redox, pH/magnetic field, temperature/reduction, double pH, pH and diols, temperature/magnetic field, temperature/enzyme, temperature/pH/redox, temperature/pH/magnetic, pH/redox/magnetic, temperature/redox/guest molecules, and temperature/pH/guest molecules have recently been developed. Notably, these combined responses take place either simultaneously at the pathological site or in a sequential manner from nanopartide preparation, nanopartide transporting pathways, to cellular compartments. These dual and multi-stimuli responsive polymeric nanoparticles have shown unprecedented control over drug delivery and release leading to superior in vitro and/or in vivo anti-cancer efficacy. With programmed site-specific drug delivery feature, dual and multi-stimuli responsive nanoparticulate drug formulations have tremendous potential for targeted cancer therapy. In this review paper, we highlight the recent exciting developments in dual and multi-stimuli responsive polymeric nanoparticles for precision drug delivery applications, with a particular focus on their design, drug release performance, and therapeutic benefits.

Keywords: cross-linked micelles; block-copolymer micelles; core-shell nanoparticles; iron-oxide nanoparticles; magnetic nanoparticles;intracellular drug; biodegradable micelles; controlled-release; triggered release; disulfide linkage

来源出版物: Biomaterials , 2013, 34(14): 3647-3657联系邮箱: Zhong, ZY; zyzhong@suda.edu.cn

被引频次: 58

Carbon "quantum" dots for optical bioimaging

Luo, PJG; Sahu, S; Yang, ST; et al.

Abstract: Carbon dots, generally referring to small carbon nanoparticles with various levels of surface passivation, have emerged as a new class of quantum dot-like fluorescent nanomaterials. Since the original report in 2006, carbon dots have been investigated by many research groups worldwide, with major advances already made in their syntheses, structural and mechanistic understandings, and evaluations for biocompatibilities and potential bio-applications. In this article, representative studies responsible for these advances in the development and understanding of carbon dots are reviewed, and those targeting the use of carbon dots as high-performance yet nontoxic fluorescence agents for optical bioimaging in vitro and in vivo are highlighted and discussed.

Keywords: one-step synthesis; in-vivo; semiconductor nanocrystals; carbogenic dots; nanoparticles; nanotubes; fluorescence; luminescence; cells; photoluminescence

来源出版物: Journal of Materials Chemistry B , 2013, 1(16): 2116-2127联系邮箱: Luo, PJG; syaping@clemson.edu

被引频次: 46

Nanostructured scaffolds for bone tissue engineering

Li, XM; Wang, L; Fan, YB; et al.

Abstract: It has been demonstrated that nanostructured materials, compared with conventional materials, may promote greater amounts of specific protein interactions, thereby more efficiently stimulating new bone formation. It has also been indicated that, when features or ingredients of scaffolds are nanoscaled, a variety of interactions can be stimulated at the cellular level. Some of those interactions induce favorable cellular functions while others may leads to toxicity. This review presents the mechanism of interactions between nanoscaled materials and cells and focuses on the current research status of nanostructured scaffolds for bone tissue engineering. Firstly, the main requirements for bone tissue engineering scaffolds were discussed. Then, the mechanism by which nanoscaled materials promote new bone formation was explained, following which the current research status of main types of nanostructured scaffolds for bone tissue engineering was reviewed and discussed.

Keywords: osteoblast-like cells; in-vitro; mechanical-properties; composite scaffolds; carbon nanotubes; physical-properties; chitin fibers;delivery; regeneration; adhesion

来源出版物: Journal of Biomedical Materials Research Part A , 2013, 101(8): 2424-2435联系邮箱: Li, XM; x.m.li@hotmail.com

被引频次: 43

Multifunctional dendrimer-entrapped gold nanoparticles for dual mode CT/MR imaging applications

Wen, SH; Li, KG; Cai, HD; et al.

Abstract: We report the synthesis, characterization, and utilization of gadolium-loaded dendrimer-entrapped gold nanoparticles(Gd-Au DENPs)for dual mode computed tomography(CD/magnetic resonance(MR)imaging applications. In this study, amine-terminated generation five poly(amidoamine)dendrimers(G5.NH2)modified with gadolinium(Gd)chelator and polyethylene glycol(PEG)monomethyl ether were used as templates to synthesize gold nanoparticles(AuNPs). Followed by sequential chelation of Gd(III)and acetylation of the remaining dendrimer terminal amine groups, multifunctional Gd-Au DENPs were formed. The formed Gd Au DENPs were characterized via different techniques. We show that the formed Gd Au DENPs are colloidally stable and non-cytotoxic at an Au concentration up to 50 gm. With the coexistence of two radiodense imaging elements of AuNPs and Gd(III)within one NP system, the formed Gd Au DENPs display both r(1)relaxivity for MR imaging mode and X-ray attenuation property for CT imaging mode, which enables CT/MR dual mode imaging of the heart, liver, kidney, and bladder of rat or mouse within a time frame of 45 min. Furthermore, in vivo biodistribution studies reveal that the Gd Au DENPs have an extended blood circulation time and can be cleared from the major organs within 24 h. The strategy to use facile dendrimer technology to design dual mode contrast agents may be extended to prepare multifunctional platforms for targeted multimode molecular imaging of various biological systems.

Keywords: ray computed-tomography; iron-oxide nanoparticles; in-vivo; magnetic-resonance; contrast agent; drug-delivery; gene delivery;MRi contrast; cancer; acetylation

来源出版物: Biomaterials , 2013, 34(5): 1570-1580联系邮箱: Shi, XY; guixiangzhang@sina.com

MATERIALS SCIENCE CERAMICS 陶瓷材料学

被引频次: 53

Field-Induced alignment controls of one-dimensional mesochannels in mesoporous materials

Yamauchi, Y

Abstract: Mesoporous materials prepared through the self-assembly of surfactants have attracted wide attention because of their many potential applications. The mesostructural, compositional, and morphological controls of mesoporous materials have been extensively studied thus far. In particular, the macroscopic alignments of one-dimensional(1D)mesochannels and their controls are quite important for the creation of advanced functional materials. In most cases, the direction of mesochannels in mesoporous films lies parallel to the substrate. Vertical orientation of the mesochannels can realize high diffusion and accessibility of guest species from the outside. Here, I review the recent progress on this emerging research field. Various methods have been proposed for the preparation of vertically oriented mesoporous thin films using high magnetic field, shear flow, modification of the substrate, and other methods. I also briefly introduce their applications and a perspective for the future.

Keywords: magnetically induced orientation; lyotropic liquid-crystals; anodic alumina membranes; doped titania films; thin-films; silica films; diblock copolymers; hexadecyltrimethylammonium bromide; mesostructured silica; standing mesochannels

来源出版物: Journal of The Ceramic Society of Japan , 2013, 121(1417): 831-840

联系邮箱: Yamauchi, Y; Yusuke@nims.go.jp

被引频次: 28

Thermoelectric Ceramics for Energy Harvesting

Koumoto, K; Funahashi, R; Guilmeau, E; et al.

Abstract: Metal oxides(Ca3Co4O9, CaMnO3, SrTiO3, In2O3), Ti sulfides, and Mn silicides are promising thermoelectric(TE)material candidates for cascade-type modules that are usable in a temperature range of 3001200 K in air. In this paper, we review previous studies in the field of TE materials development and make recommendations for each material regarding future research. Furthermore, the R&D of TE modules composed of metal oxide materials and the prospect of their commercialization for energy harvesting is demonstrated.

Keywords: misfit-layer compounds; nb-doped srtio3; 2-dimensional electron-gas; higher manganese silicide; high-temperature; singlecrystals; thermal-conductivity; indium oxide; thin-films; semiconducting properties

来源出版物: Journal of The American Ceramic Society , 2013, 96(1): 1-23联系邮箱: Wan, CL; chunlei.wan@gmail.com

被引频次: 23

The effect of group-I elements on the structural and optical properties of ZnO nanoparticles

Yousefi, R; Zak, AK; Jamali-Sheini, F

Abstract: Undoped and group-I elements doped ZnO nanoparticles(NPs)(Zn1-yX2yO, X=Li, Na, K, and y=0.05)were synthesized by a sol-gel method. Structural and morphological studies of the resulting products were carried out by X-ray diffraction analysis(XRD)and transmission electron microscopy(TEM). The XRD results revealed that the sample products were crystalline with a hexagonal wurtzite phase. The TEM images showed ZnO NPs with nearly spherical shapes with particle size distributed over the nanometer range. In addition,the XRD and TEM results showed a decrease in crystallite and particle sizes of NPs from Li-doped to K-doped ZnO NPs. Crystalline development in the ZnO NPs was investigated by X-ray peak broadening. The size-strain plot(SSP)method was used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of the undoped and doped ZnO NPs. The effect of doping on the optical band-gap and crystalline quality was also investigated by using photoluminescence(PL)and Raman spectrometers. The Raman spectra of the all ZnO NPs showed a strong E-2(high)peak. The PL spectra exhibited a strong peak in the ultraviolet(UV)region of the electromagnetic spectrum for the all ZnO NPs. The UV peak of the doped ZnO NPs was red-shifted with respect to that of the undoped ZnO NPs.

Keywords: nanowires; films; Li; fabrication; oxide

来源出版物: Ceramics International , 2013, 39(2): 1371-1377联系邮箱: Yousefi, R; yousefi.ramin@gmail.com

被引频次: 20

Decoding the Fingerprint of Ferroelectric Loops: Comprehension of the Material Properties and Structures

Jin, L; Li, F; Zhang, SJ

Abstract: Due to the nature of domains, ferroics, including ferromagnetic, ferroelectric, and ferroelastic materials, exhibit hysteresis phenomena with respect to external driving fields(magnetic field, electric field, or stress). In principle, every ferroic material has its own hysteresis loop, like a fingerprint, which contains information related to its properties and structures. For ferroelectrics, many characteristic parameters, such as coercive field, spontaneous, and remnant polarizations can be directly extracted from the hysteresis loops. Furthermore,many impact factors, including the effect of materials(grain size and grain boundary, phase and phase boundary, doping, anisotropy, thickness), aging(with and without poling), and measurement conditions(applied field amplitude, fatigue, frequency, temperature, stress), can affect the hysteretic behaviors of the ferroelectrics. In this feature article, we will first give the background of the ferroic materials and multiferroics, with an emphasis on ferroelectrics. Then it is followed by an introduction of the characterizing techniques for the loops, including the polarization-electric field loops and strain-electric field curves. A caution is made to avoid misinterpretation of the loops due to the existence of conductivity. Based on their morphologic features, the hysteresis loops are categorized to four groups and the corresponding material usages are introduced. The impact factors on the hysteresis loops are discussed based on recent developments in ferroelectric and related materials. It is suggested that decoding the fingerprint of loops in ferroelectrics is feasible and the comprehension of the material properties and structures through the hysteresis loops is established.

Keywords: zirconate-titanate ceramics; modified lead-zirconate; free(1-x)(bi1/2na1/2)tio3-xbatio(3)ceramics; piezoresponse force microscopy; free piezoelectric ceramics; domain-structure evolution; templated grain-growth; field-induced strain; soft pzt ceramics; single-crystals

来源出版物: Journal of The American Ceramic Society , 2014, 97(1): 1-27联系邮箱: Zhang, SJ; sozl@psu.edu

被引频次: 20

Piezoelectric properties and temperature stabilities of Mn- and Cu-modified BiFeO3-BaTiO3 high temperature ceramics

Yang, HB; Zhou, CR; Liu, XY; et al.

Abstract: The structures, microstructures, electrical properties and the thermal stability have been investigated for the MnO2-doped(1-x)BF-xBT system and the MnO2and CuO-doped(1-x)BF-xBT system, where x ranges from 0.25 to 0.35. The XRD analysis shows that the two systems have a single perovskite phase, and the MnO2and CuO-doped(1-x)BF-xBT system has a morphotropic phase boundary(MPB)with the coexistence of rhombohedral and pseudo-cubic phases in the system about x=0.325. The addition of small. amount of CuO was quite effective to lower the sintering temperature. The diffusive phase transition characteristics were observed in the MnO2-doped(1-x)BF-xBT system and a normal ferroelectric phase transition characteristics were observed in the MnO2and CuO doped(1-x)BF-xBT system. Compared with the MnO2doped(1-x)BF-xBT system, the epsilon(m), Curie temperature(T-c), depoling temperature(T-d), and piezoelectrical properties were improved evidently with the MnO2and CuO doping.

Keywords: zirconate-titanate ceramics; solid-solution; dependence; microstructure; piezoceramics

来源出版物: Journal of The European Ceramic Society , 2013, 33(6): 1177-1183联系邮箱: Zhou, CR; zcr750320@yahoo.com.cn

MATERIALS SCIENCE CHARACTERIZATION TESTING 材料科学,表征与测试

被引频次: 26

Progress on the preparation of nanocrystalline apatites and surface characterization: Overview of fundamental and applied aspects

Gomez-Morales, J; Iafisco, M; Delgado-Lopez, JM; et al.

Abstract: Nanocrystalline calcium phosphate apatites constitute the main inorganic part of hard tissues, and a growing focus is devoted to prepare synthetic analogs, so-called "biomimetic", able to precisely mimic the morphological and physico-chemical features of biological apatite compounds. Both from fundamental and applied viewpoints, an accurate characterization of nanocrystalline apatites, including their peculiar surface features, and a deep knowledge of crystallization aspects are prerequisites to attempt understanding mineralization phenomena in vivo as well as for designing innovative bioactive materials that may then find applications in bone tissue engineering, either as self-supported scaffolds and fillers or in the form of coatings, but also in other domains such as drug delivery or else medical imaging. Also,interfacial phenomena are of prime importance for getting a better insight of biomineralization and for following the behavior of biomaterials in or close to their final conditions of use. In this view, both adsorption and ion exchange represent essential processes involving the surface of apatite nanocrystals, possibly doped with foreign elements or functionalized with organic molecules of interest. In this review paper, we will address these various points in details based on a large literature survey. We will also underline the fundamental physico-chemical and behavioral differences that exist between nanocrystalline apatites(whether of biological origin or their synthetic biomimetic analogs)and stoichiometric hydroxyapatite.

Keywords: calcium-phosphate coatings; atomic-force microscopy; biomimetic hydroxyapatite nanocrystals; mechanochemical-hydrothermal synthesis; bone morphogenetic protein; nuclear-magnetic-resonance; transform infrared-spectroscopy; electrostatic spray deposition; poorly crystalline apatites; dynamic light-scattering

来源出版物: Progress in Crystal Growth and Characterization of Materials , 2013, 59(1): 1-46联系邮箱: Drouet, C; jaime@lec.csic.es

被引频次: 19

Realistic pore structure of Portland cement paste: experimental study and numerical simulation

Ma, HY; Li, ZJ

Abstract: In this study, the pore structure of Portland cement paste is experimentally characterized by MIP(mercury intrusion porosimetry)and nitrogen adsorption, and simulated by a newly developed status-oriented computer model. Cement pastes with w/c= 0.3, 0.4 and 0.5 at ages from 1 day to 120 days are comprehensively investigated. It is found that MIP cannot generate valid pore size distribution curves for cement paste. Nevertheless, nitrogen adsorption can give much more realistic pore size distribution curves of small capillary pores, and these curves follow the same distribution mode. While, large capillary pores can be effectively characterized by the newly developed computer model, and the validity of this model has been proved by BSE imaging plus image analysis. Based on the experimental findings and numerical simulation, a hypothesis is proposed to explain the formation mechanism of the capillary pore system, and the realistic representation of the pore structure of hydrated cement paste is established.

Keywords: mercury intrusion porosimetry; microstructure development; hydration; permeability; space; water

来源出版物: Computers and Concrete , 2013, 11(4): 317-336联系邮箱: Li, ZJ; zongjin@ust.hk

被引频次: 18

Experimental Technique for Measuring the Long-term Transfer Length in Prestressed Concrete

Marti-Vargas, JR; Caro, LA; Serna, P

Abstract: This article presents a proposal of a test set-up and methodology for testing the transfer length evolution through time of prestressing reinforcement in pretensioned prestressed concrete members, aimed at providing a basis for standardization. The proposed testmethod is based on the instantaneous and time-related analysis of the prestressing reinforcement force profile at only one end of a pretensioned prestressed concrete member. The basis of the test method and the requirements of the prestressing frame and its components are presented, as well as the test procedure stages and the measurement devices. The interpretation of the test results and the criteria to determine both the initial and the long-term transfer lengths are explained. A test method application and the equipment for testing seven-wire prestressing strands have been designed. Some experimental results are provided to validate the test. A comparative analysis of test reliability with other existing experimental methods is also included.

Keywords: pretensioned concrete; strand; girders; bond; members

来源出版物: Strain , 2013, 49(2): 125-134

被引频次: 17

Time-dependent evolution of strand transfer length in pretensioned prestressed concrete members

Caro, LA; Marti-Vargas, JR; Serna, P

Abstract: For design purposes, it is generally considered that prestressing strand transfer length does not change with time. However, some experimental studies on the effect of time on transfer lengths show contradictory results. In this paper, an experimental research to study transfer length changes over time is presented. A test procedure based on the ECADA testing technique to measure prestressing strand force variation over time in pretensioned prestressed concrete specimens has been set up. With this test method, an experimental program that varies concrete strength, specimen cross section, age of release, prestress transfer method, and embedment length has been carried out. Both the initial and long-term transfer lengths of 13-mm prestressing steel strands have been measured. The test results show that transfer length variation exists for some prestressing load conditions, resulting in increased transfer length over time. The applied test method based on prestressing strand force measurements has shown more reliable results than procedures based on measuring free end slips and longitudinal strains of concrete. An additional factor for transfer length models is proposed in order to include the time-dependent evolution of strand transfer length in pretensioned prestressed concrete members.

Keywords: self-consolidating concrete; fiber-reinforced polymers; high-strength concrete; bridge girders; transmission length; bond; cast;performance; beams; equation

来源出版物: Mechanics of Time-dependent Materials , 2013, 17(4): 501-527联系邮箱: Marti-Vargas, JR; licafo@doctor.upv.es

被引频次: 16

Characterization of PLA-limonene blends for food packaging applications

Arrieta, MP; Lopez, J; Ferrandiz, S; et al.

Abstract: Polymers derived from renewable resources are now considered as promising alternatives to traditional petro-polymers as they mitigate current environmental concerns(raw renewable materials/biodegradability). D-limonene can be found in a variety of citrus, indeed is the main component of citrus oils and one of most important contributors to citrus flavor. The incorporation of limonene in PLA matrix was evaluated and quantified by Pyrolysis Gas Chromatography Mass Spectrometry(Py-GC/MS). Transparent films were obtained after the addition of the natural compound. Mechanical properties were evaluated by tensile tests. The effect of limonene on mechanical properties of PLA films was characterized by an increase in the elongation at break and a decrease in the elastic modulus. The fracture surface structure of films was evaluated by scanning electron microscopy(SEM), and homogeneous surfaces were observed in all cases. Barrier properties were reduced due to the increase of the chain mobility produced by the D-limonene.

Keywords: biodegradable multiphase systems; poly(lactic acid); mechanical-properties; barrier properties; orange juice; films; pyrolysis;antioxidants; composites; polymers

来源出版物: Polymer Testing , 2013, 32(4): 760-768联系邮箱: Arrieta, MP; marrieta@itm.upv.es

(责任编辑姚玉琴)

A review of mineral carbonation technology in sequestration of CO2

Olajire, AA

Mineral carbonation technology(MCT)is a process whereby CO2is chemically reacted with calcium-and/or magnesiumcontaining minerals to form stable carbonate materials which do not incur any long-term liability or monitoring commitments. Mineral carbonation is a potentially attractive sequestration technology for the permanent and safe storage of CO2. Vast amounts of magnesium silicate minerals exist worldwide that may be carbonated, with magnesium carbonate as stable and environmentally harmless product. In this review, a number of processes under development, such as the Abo Akademi University(AA)Process routes, the CO2Energy Reactor(c), and the chemical and biological catalytic enhancement as new carbon capture and sequestration(CCS)technology are discussed. The key factors of the mineral CO2sequestration process are identified, their influence on the carbonation process and environmental impact of the reaction products with regard to their possible beneficial utilization are critically evaluated. Chemistry and comparative analysis of residues and ores carbonation processes, as well as cost and gap analyses of this technology are discussed.

incinerator bottom ash; olivine dissolution kinetics; fly-ash; wollastonite carbonation; accelerated carbonation; dioxide sequestration; calcite precipitation; aqueous carbonation; industrial-wastes; steelmaking slags

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