3,581 research outputs found

    Responses of seasonal indicators to extreme droughts in southwest China

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    Significant impact of extreme droughts on human society and ecosystem has occurred in many places of the world, for example, Southwest China (SWC). Considerable research concentrated on analyzing causes and effects of droughts in SWC, but few studies have examined seasonal indicators, such as variations of surface water and vegetation phenology. With the ongoing satellite missions, more and more earth observation data become available to environmental studies. Exploring the responses of seasonal indicators from satellite data to drought is helpful for the future drought forecast and management. This study analyzed the seasonal responses of surface water and vegetation phenology to drought in SWC using the multi-source data including Seasonal Water Area (SWA), Permanent Water Area (PWA), Start of Season (SOS), End of Season (EOS), Length of Season (LOS), precipitation, temperature, solar radiation, evapotranspiration, the Palmer Drought Severity Index (PDSI), the Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), Gross Primary Productivity (GPP) and data from water conservancy construction. The results showed that SWA and LOS effectively revealed the development and recovery of droughts. There were two obvious drought periods from 2000 to 2017. In the first period (from August 2003 to June 2007), SWA decreased by 11.81% and LOS shortened by 5 days. They reduced by 21.04% and 9 days respectively in the second period (from September 2009 to June 2014), which indicated that there are more severe droughts in the second period. The SOS during two drought periods delayed by 3~6 days in spring, while the EOS advanced 1~3 days in autumn. All of PDSI, SWA and LOS could reflect the period of droughts in SWC, but the LOS and PDSI were very sensitive to the meteorological events, such as precipitation and temperature, while the SWA performed a more stable reaction to drought and could be a good indicator for the drought periodicity. This made it possible for using SWA in drought forecast because of the strong correlation between SWA and drought. Our results improved the understanding of seasonal responses to extreme droughts in SWC, which will be helpful to the drought monitoring and mitigation for different seasons in this ecologically fragile region

    Bis(μ-3,5-difluorobenzoato)bis[(3,5-di­fluorobenzoato)dimethyltin(IV)]

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    In the dinuclear title complex, [Sn2(CH3)4(C7H3F2O2)4], the SnIV atom is chelated by two 3,5-difluoro­benzoate (dfb) anions and coordinated by two methyl groups while an O atom from the adjacent dfb anion bridges the Sb atom with a longer Sb—O bond distance of 2.793 (4) Å. The complex mol­ecule has 2 symmetry and the SnIV atom is in a distorted penta­gonal–bipyramidal coordination geometry. In the crystal, mol­ecules are connected by C—H⋯O and C—H⋯F hydrogen bonds

    Phase Separation in two-Species Atomic Bose-Einstein Condensate with Interspecies Feshbach Resonance

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    We consider a mixture of two-species atomic Bose-Einstein codensates coupled to a bound molecular state at zero temperature via interspecies Feshbach resonance. The interspecies Feshbach coupling precludes the possibility of doubly mixed phases while enables not only the pure molecular superfluid but also the pure atomic superfluids to exist as distinct phases. We show that this system is able to support a rich set of phase separations, including that between two distinct mixed atom-molecule phases. We pay particular attention to the effects of the Feschbach coupling and the particle collisions on the miscibility of this multi-component condensate system.Comment: 9 pages, 3 figure

    Evaluating diabetes and hypertension disease causality using mouse phenotypes

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    <p>Abstract</p> <p>Background</p> <p>Genome-wide association studies (GWAS) have found hundreds of single nucleotide polymorphisms (SNPs) associated with common diseases. However, it is largely unknown what genes linked with the SNPs actually implicate disease causality. A definitive proof for disease causality can be demonstration of disease-like phenotypes through genetic perturbation of the genes or alleles, which is obviously a daunting task for complex diseases where only mammalian models can be used.</p> <p>Results</p> <p>Here we tapped the rich resource of mouse phenotype data and developed a method to quantify the probability that a gene perturbation causes the phenotypes of a disease. Using type II diabetes (T2D) and hypertension (HT) as study cases, we found that the genes, when perturbed, having high probability to cause T2D and HT phenotypes tend to be hubs in the interactome networks and are enriched for signaling pathways regulating metabolism but not metabolic pathways, even though the genes in these metabolic pathways are often the most significantly changed in expression levels in these diseases.</p> <p>Conclusions</p> <p>Compared to human genetic disease-based predictions, our mouse phenotype based predictors greatly increased the coverage while keeping a similarly high specificity. The disease phenotype probabilities given by our approach can be used to evaluate the likelihood of disease causality of disease-associated genes and genes surrounding disease-associated SNPs.</p

    The linear and nonlinear Jaynes-Cummings model for the multiphoton transition

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    With the Jaynes-Cummings model, we have studied the atom and light field quantum entanglement of multiphoton transition, and researched the effect of initial state superposition coefficient C1C_{1}, the transition photon number NN, the quantum discord δ\delta and the nonlinear coefficient χ\chi on the quantum entanglement degrees. We have given the quantum entanglement degrees curves with time evolution, and obtained some results, which should have been used in quantum computing and quantum information.Comment: arXiv admin note: text overlap with arXiv:1404.0821, arXiv:1205.0979 by other author

    Effect of total flavones of buckwheat flowers and leaves on protein tyrosine phosphatase 1B expression in type 2 diabetic rats

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    The total flavone content was obtained from flowers and leaf of buckwheat (Fagopyrum esculentum Moench) by heating reflux method. The effects of the total flavone extract on the protein tyrosine phosphatase 1B (PTP1B) expression in type 2 diabetic rats were evaluated by immunofluorescence, western blotting and real-time quantitative PCR. The results suggested that the total flavone fraction from buckwheat flowers and leaves can significantly decrease the PTP1B expression in liver.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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