检索结果-南通市图书馆

Operator Splitting for Three-Phase Flow in Heterogeneous Porous Media

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2009年第6期6卷 72-84页

作者： E.Abreu J.douglas F.Furtado F.Pereira Instituto Nacional de Matematica Pura e Aplicada RJ 22460-320Brazil Department of Mathematics Purdue UniversityWest LafayetteIN 47907-1395USA Department of Mathematics University of WyomingLaramieWY 82071-3036USA Department of Mathematics and School of Energy Resources University of WyomingLaramieWY 82071-3036USA

We describe an operator splitting technique based on physics rather than on dimension for the numerical solution of a nonlinear system of partial differential equations which models three-phase flow through heterogeneous porous *** model for three-phase flow considered in this work takes into account capillary forces,general relations for the relative permeability functions and variable porosity and permeability *** our numerical procedure a high resolution,nonoscillatory,second order,conservative central difference scheme is used for the approximation of the nonlinear system of hyperbolic conservation laws modeling the convective transport of the fluid *** scheme is combined with locally conservative mixed finite elements for the numerical solution of the parabolic and elliptic problems associated with the diffusive transport of fluid phases and the pressure-velocity *** numerical procedure has been used to investigate the existence and stability of nonclassical shock waves(called transitional or undercompressive shock waves)in two-dimensional heterogeneous flows,thereby extending previous results for one-dimensional flow *** experiments indicate that the operator splitting technique discussed here leads to computational efficiency and accurate numerical results.

关键词： Operator splitting three-phase flow heterogeneous porous media central differencing schemes mixed finite elements

Testing three pipelines for 18S rDNA-based metabarcoding of soil faunal diversity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2013年第1期56卷 73-81页

作者： YANG ChenXue JI YingQiu WANG XiaoYang YANG ChunYang YU douglas W. Ecology Conservationand Environment CenterState Key Laboratory of Genetic Resources and EvolutionKunming Institute of ZoologyChinese Academy of Sciences School of Biological Sciences University of East Anglia

A number of basic and applied questions in ecology and environmental management require the characterization of soil and leaf litter faunal diversity. Recent advances in high-throughput sequencing of barcode-gene amplicons ('metabarcoding') have made it possible to survey biodiversity in a robust and efficient way. However, one obstacle to the widespread adoption of this technique is the need to choose amongst many candidates for bioinformatic processing of the raw sequencing data. We compare three candidate pipelines for the processing of 18S small subunit rDNA metabarcode data from solid substrates: (i) USEARCH/CROP, (ii) Denoiser/UCLUST, and (iii) OCTUPUS. The three pipelines produced reassuringly similar and highly correlated assessments of community composition that are dominated by taxa known to characterize the sampled environments. However, OCTUPUS appears to inflate phylogenetic diversity, because of higher sequence noise. We therefore recommend either the USEARCH/CROP or Denoiser/UCLUST pipelines, both of which can be run within the QIIME (Quantitative Insights Into Microbial Ecology) environment.

关键词： 454 Genome Sequencer FLX System DNA barcoding high-throughput sequencing soil fauna metabarcoding 18SrDNA

Field cracking performance of airfield rigid pavements

在线全文

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2017年第4期4卷 380-387页

作者： Yusuf Mehta douglas Cleary Ayman W. Ali Department of Civil and Environmental Engineering Rowan University Glassboro NJ 08028 USA Center for Research and Education in Advanced Transportation Engineering Systems (CREATEs) Rowan University Glassboro NJ 08028 USA

This paper discusses cracking in airport pavements as studied in Construction Cycle 6 of testing carried out at the National Airport Pavement Testing Facility by the Federal Aviation Administration. Pavements of three different flexural strengths as well as two different subgrades, a soft bituminous layer and a more rigid layer known as econocrete, were tested. In addition to this, cracking near two types of isolated transition joints, a reinforced edge joint and a thickened edge joint, was considered. The pavement sections were tested using a moving load simulating that of an aircraft. It has been determined that the degree of cracking was reduced as the flexural strength of the pavement was increased and that fewer cracks formed over the econocrete base than over the bituminous base. In addition, the thickened edge transition joint was more effective in preventing cracking at the edges compared to the reinforced edge joint.

关键词： Base layer Corner cracking Longitudinal cracking Airfield rigid pavement

Online Healthcare Community Interaction Dynamics

在线全文

学校读者我要写书评

暂无评论

Journal of Management Science and Engineering 2016年第1期1卷 58-74页

作者： Xitong Guo Shanshan Guo douglas Vogel Yijun Li School of Management Harbin Institute of Technology150001 HarbinChina Department of Management Sciences National Natural Science Foundation of China(NSFC)Beijing 100085China

With the increasing dilemma of the rapid global demand for healthcare services(often in the presence of limited resources),how to creatively allocate and use healthcare resources across a widespread population has become a salient *** healthcare communities(OHCs)are regarded as a potential ICT-based partial *** contrast to traditional healthcare,online doctor-patient interaction is unlimited in terms of time and space limitations while an OHC is exposed to the whole *** characteristics are key to achieving synergistic doctor-patient interaction and community development in the longer *** order to explore the nature of doctor-patient interaction dynamics in an OHC,we systematically investigate doctor-patient interaction dynamics from the dual perspectives of doctor and *** doctor-patient interaction dual-cycle model has been built based on six doctor-patient interaction processes(i.e.,searching,choosing,knowledge sharing,providing,receiving and balancing).According to our dual-cycle model,four key managerial issues in OHC(information asymmetry,incentive mechanisms,service delivery processes and interaction mechanisms)have been identified as *** and directions for future research,with challenges as well as opportunities,have been elaborated.A broad view with fruitful research potential is ensured and new theories and methods ultimately provide implications for effectively and efficiently allocating scarce healthcare resources to a broader population.

关键词： Online Healthcare Community Doctor-Patient Interaction Dual-Cycle Model Interaction Dynamics Incentive Mechanisms

Quantifying golf course nitrogen use efficiency

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Grassland Research 2022年第3期1卷 174-186页

作者： Michael A.H.Bekken douglas J.Soldat Department of Soil Science University of Wisconsin-MadisonMadisonWisconsinUSA

Background:Previous studies have surveyed golf courses to determine nitrogen(N)fertilizer application rates on golf courses,but no previous studies have attempted to quantify how efficiently golf courses use ***:This study tests the ability of the growth potential(GP)N Requirement model as a benchmarking tool to predict a target level of N use on 76 golf courses in 5 regions of the US(Midwest,Northeast,East Texas,Florida,Northwest)and 3 countries in Europe(Denmark,Norway,UK).Results:The ratio of the golf course-wide N application rate to the GP N requirement prediction(termed the nitrogen efficiency score or NES)was 0.27,indicating that golf courses used 73%less N than predicted by the *** such,the GP N Requirement model needs to be recalibrated to predict N use on golf *** was achieved by adjusting the Nmax coefficient in the model.N rates on golf courses were widely variable both within and across *** regions had a coefficient of variation in N rates of 0.46 or ***:The high variation in N rates,which is largely unexplained by climate,economic factors,grass type,and soil type,may be indicative of inefficient N use in golf course management.

关键词： biophysical modeling decision support tools fertilizer golf growth potential nitrogen nitrogen efficiency turfgrass

The use of hydrogel-delivered extracellular vesicles in recovery of motor function in stroke:a testable experimental hypothesis for clinical translation including behavioral and neuroimaging assessment approaches

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2021年第4期16卷 605-613页

作者： Magdalini Tsintou Kyriakos Dalamagkas Tara LMoore Yogesh Rathi Marek Kubicki douglas LRosene Nikos Makris Departments of Psychiatry and Neurology Services Center for Neural Systems InvestigationsCenter for Morphometric AnalysisAthinoula A.Martinos Center for Biomedical ImagingMassachusetts General HospitalHarvard Medical SchoolBostonMAUSA Department of Psychiatry Psychiatry Neuroimaging LaboratoryBrigham and Women’s HospitalHarvard Medical SchoolBostonMAUSA University College of London Division of Surgery&Interventional Science Center for Nanotechnology&Regenerative MedicineUniversity College LondonLondonUK Department of Physical Medicine and Rehabilitation The University of Texas Health Science Center at HoustonHoustonTXUSA The Institute for Rehabilitation and Research Memorial Hermann Research Center The Institute for Rehabilitation and Research Memorial Hermann HospitalHoustonTXUSA Department of Anatomy&Neurobiology Boston University School of MedicineBostonMAUSA

Neural tissue engineering,nanotechnology and neuroregeneration are diverse biomedical disciplines that have been working together in recent decades to solve the complex problems linked to central nervous system(CNS)*** is known that the CNS demonstrates a very limited regenerative capacity because of a microenvironment that impedes effective regenerative processes,making development of CNS therapeutics *** the high prevalence of CNS conditions such as stroke that damage the brain and place a severe burden on afflicted individuals and on society,it is of utmost significance to explore the optimum methodologies for finding treatments that could be applied to humans for restoration of function to pre-injury *** vesicles(EVs),also known as exosomes,when derived from mesenchymal stem cells,are one of the most promising approaches that have been attempted thus far,as EVs deliver factors that stimulate recovery by acting at the nanoscale level on intercellular communication while avoiding the risks linked to stem cell *** the same time,advances in tissue engineering and regenerative medicine have offered the potential of using hydrogels as bio-scaffolds in order to provide the stroma required for neural repair to occur,as well as the release of biomolecules facilitating or inducing the reparative *** review introduces a novel experimental hypothesis regarding the benefits that could be offered if EVs were to be combined with biocompatible injectable *** rationale behind this hypothesis is presented,analyzing how a hydrogel might prolong the retention of EVs and maximize the localized benefit to the *** sustained delivery of EVs would be coupled with essential guidance cues and structural support from the hydrogel until neural tissue remodeling and regeneration ***,the importance of including nonhuman primate models in the clinical translation pipeline,as well as the added benefit of m

关键词： cortical injury exosomes extracellular vesicles hydrogels neural tissue engineering neural tissue repair neuroregeneration non-human primates stroke

In Vivo Phosphorylation Site Mapping and Functional Characterization of Arabidopsis Phototropin 1

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2008年第1期1卷 178-194页

作者： Stuart Sullivan Catriona E. Thomson douglas J. Lamont Matthew A. Jones John M. Christie Plant Science Group Division of Biochemistry and Molecular Biology. Institute of Biomedical and Life Sciences University of Glasgow. University Avenue. Glasgow Scotland UK FingerPrints Proteomics Facility Post-Genomics and Molecular Interactions Centre. School of Life Sciences MSI/WTB/CIR Complex University of Dundee. Dundee Scotland UK

Phototropins （phot1 and phot2） are blue-light receptor kinases controlling a range of responses that optimize the photosynthetic efficiency of plants. Light sensing is mediated by two flavin-binding motifs, known as LOVl and LOV2, located within the N-terminal region of the protein. Photoexcitation via LOV2 leads to activation of the C-terminal kinase domain and consequently receptor autophosphorylation. However, knowledge of the in-vivo phosphorylation sites for Arabidopsis phototropins is lacking and has impeded progress in elucidating the functional significance of receptor phos- phorylation. We have purified photl from Arabidopsis and identified the in-vivo sites of receptor phosphorylation by liquid chromatography tandem mass spectrometry. Arabidopsis-derived photl binds flavin mononucleotide as chromophore and is phosphorylated at four major sites located upstream of LOV2 （Ser^58, Ser^85, Ser^350, and Ser^410）, three of which are induced by blue light. Nevertheless, structure-function analysis indicates that the biological activity of photl can be attributed to a modular unit comprising the LOV2-kinase region of the protein. Thus, peptide regions upstream of LOV2, including the sites of receptor phosphorylation identified here, do not appear to be important for receptor signaling. By contrast, these regions may be necessary for maximizing stomatal performance and possibly light-induced relocalization of photl.

关键词： MODULAR UNIT Phototropins chromophores Phosphorylation Site Function analysis Upstream photosynthetic efficiency Arabidopsis PHOSPHONATION Receptor Signaling Flavin Mononucleotide Receptor

Food contamination as a pathway for lead exposure in children during the 2010–2013 lead poisoning epidemic in Zamfara,Nigeria

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2018年第5期30卷 260-272页

作者： Simba Tirima Casey Bartrem Ian von Lindern Margrit von Braun douglas Lind Shehu Mohamed Anka Aishat Abdullahi TerraGraphics International Foundation MoscowID 83843USA University of Idaho Environmental Science ProgramMoscowID 83843USA Zamfara Environmental Sanitation Agency Zamfara StateNigeria

In 2010, an estimated 400 to 500 children died of acute lead poisoning associated with artisanal gold mining in Zamfara, Nigeria. Processing of gold ores containing up to 10% lead within residential compounds put residents, especially children, at the highest risk. Principal routes of exposure were incidental ingestion and inhalation of contaminated soil and dusts. Several Nigerian and international health organizations collaborated to reduce lead exposures through environmental remediation and medical treatment. The contribution of contaminated food to total lead exposure was assessed during the environmental health response. Objectives of this investigation were to assess the influence of cultural/dietary habits on lead exposure pathways and estimate the contribution of contaminated food to children＇s blood lead levels（BLLs）. A survey of village dietary practices and staple food lead content was conducted to determine dietary composition, caloric intakes, and lead intake. Potential blood lead increments were estimated using bio-kinetic modeling techniques. Most dietary lead exposure was associated with contamination of staple cereal grains and legumes during post-harvest processing and preparation in contaminated homes. Average post-harvest and processed cereal grain lead levels were 0.32 mg/kg and 0.85 mg/kg dry weight, respectively. Age-specific food lead intake ranged from 7 to 78 μg/day. Lead ingestion and absorption were likely aggravated by the dusty environment, fasting between meals, and nutritional deficiencies. Contamination of staple cereal grains by highly bioavailable pulverized ores could account for as much as 11%–34% of children＇s BLLs during the epidemic, and were a continuing source after residential soil remediation until stored grain inventories were exhausted.

关键词： Artisanal mining Environmental health Lead poisoning Nigerian environmentalcontamination Dietary exposures Para-occupational exposuresChildren's health

Projections of the Advance in the Start of the Growing Season during the 21st Century Based on CMIP5 Simulations

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2015年第6期32卷 831-838页

作者： XIA Jiangjiang YAN Zhongwei JIA Gensuo ZENG Heqing Philip douglas JONES ZHOU Wen ZHANG Anzhi Key Laboratory of Regional Climate-Environment for East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences Ministry of Environmental Protection of Jiuzhaigou Country Climatic Research Unit University of East Anglia Center of Excellence for Climate Change Research and Department of Meteorology King Abdulaziz University Guy Carpenter Asia-Pacific Climate Impact Centre School of Energy and EnvironmentCity University of Hong Kong

It is well-known that global warming due to anthropogenic atmospheric greenhouse effects advanced the start of the vegetation growing season （SOS） across the globe during the 20th century. Projections of further changes in the SOS for the 21st century under certain emissions scenarios （Representative Concentration Pathways, RCPs） are useful for improving understanding of the consequences of global warming. In this study, we first evaluate a linear relationship between the SOS （defined using the normalized difference vegetation index） and the April temperature for most land areas of the Northern Hemisphere for 1982-2008. Based on this relationship and the ensemble projection of April temperature under RCPs from the latest state-of-the-art global coupled climate models, we show the possible changes in the SOS for most of the land areas of the Northern Hemisphere during the 21st century. By around 2040-59, the SOS will have advanced by -4.7 days under RCP2.6, -8.4 days under RCP4.5, and -10.1 days under RCPS.5, relative to 1985-2004. By 2080-99, it will have advanced by -4.3 days under RCP2.6, -11.3 days under RCP4.5, and -21.6 days under RCP8.5. The geographic pattern of SOS advance is considerably dependent on that of the temperature sensitivity of the SOS. The larger the temperature sensitivity, the larger the date-shift-rate of the SOS.

关键词： start of growing season (SOS) normalized difference vegetation index (NDVI) temperature sensitivity Repre-sentative Concentration Pathways (RCPs) CMIP5