检索结果-南通市图书馆

A test of two mechanisms proposed to optimize grassland aboveground primary productivity in response to grazing

Journal of Plant Ecology 2012年第4期5卷 357-365页

作者： A.K.Knapp D.L.Hoover J.M.Blair G.Buis D.E.Burkepile A.Chamberlain S.L.Collins R.W.S.Fynn K.P.Kirkman M.D.Smith D.Blake n.govender P.O'neal T.Schreck A.Zinn Graduate Degree Program in Ecology and Department of Biology Colorado State UniversityFort CollinsCO 80526USA Division of Biology Kansas State UniversityManhattanKS 66506USA Department of Biological Sciences Florida International UniversityNorth MiamiFL 33181USA Department of Biology MSC03-2020University of New MexicoAlbuquerqueNM 87131USA Okavango Research Institute University of BotswanaPrivate Bag 285MaunBotswana School of Biological and Conservation Science University of KwaZulu-NatalPrivate Bag X01Scottsville 3209PietermaritzburgSouth Africa Department of Ecology and Evolutionary Biology Yale UniversityNew HavenCT 06520USA Scientific Services Kruger National ParkPrivate Bag X402Skukuza1350South Africa Department of Ecology and Evolutionary Biology University of CaliforniaIrvineCA 92697USA

Aims Mesic grasslands have a long evolutionary history of grazing by large herbivores and as a consequence,grassland species have numerous adaptations allowing them to respond favourably to *** empirical evidence has been equivocal,theory predicts that such adaptations combined with alterations in resources can lead to grazing-induced overcompensation in aboveground net primary production(AnPP;grazed AnPP>ungrazed AnPP)under certain *** tested two specific predictions from ***,overcompensation is more likely to occur in annually burned grasslands because limiting nutrients that would be lost with frequent fires are recycled through grazers and stimulate ***,overcompensation of biomass lost to grazers is more likely to occur in unburned sites where grazing has the greatest effect on increasing light availability through alterations in canopy *** We tested these nutrient versus light-based predictions in grazed grasslands that had been annually burned or protected from fire for>20 *** assessed responses in AnPP to grazing by large ungulates using both permanent and moveable grazing exclosures(252 exclosures from which biomass was harvested from 3192 quadrats)in a 2-year *** sites were located at the Konza Prairie Biological Station(KPBS)in north America and at Kruger national Park(KnP)in South *** KPBS,sites were grazed by north American bison whereas in KnP sites were grazed either by a diverse suite of herbivores(*** wildebeest,Burchell’s zebra,African buffalo)or by a single large ungulate(African buffalo).Important Findings We found no evidence for overcompensation in either burned or unburned sites,regardless of grazer ***,there was no support for either mechanism leading to ***,complete compensation of total biomass lost to grazers was the most common response characterizing grazing–AnPP relationships with,in some cases,undercompensation of grass AnPP being of

关键词： aboveground net primary production fire forbs herbivores savanna

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Disaster Impacts Surveillance from Social Media with Topic Modeling and Feature Extraction: Case of Hurricane Harvey

引用

International Journal of Disaster Risk Science 2022年第5期13卷 729-742页

作者： Volodymyr V.Mihunov navid H.Jafari Kejin Wang nina S.n.Lam Dylan.govender Department of Environmental Sciences Louisiana State UniversityBaton RougeLA 70803USA Department of Civil and Environmental Engineering Louisiana State UniversityBaton RougeLA 70803USA Division of Electrical and Computer Engineering Louisiana State UniversityBaton RougeLA 70803USA

Twitter can supply useful information on infrastructure impacts to the emergency managers during major disasters,but it is time consuming to filter through many irrelevant *** studies have identified the types of messages that can be found on social media during disasters,but few solutions have been proposed to efficiently extract useful *** present a framework that can be applied in a timely manner to provide disaster impact information sourced from social *** framework is tested on a well-studied and data-rich case of Hurricane *** procedures consist of filtering the raw Twitter data based on keywords,location,and tweet attributes,and then applying the latent Dirichlet allocation(LDA) to separate the tweets from the disaster affected area into categories(topics) useful to emergency *** LDA revealed that out of 24 topics found in the data,nine were directly related to disaster impacts-for example,outages,closures,flooded roads,and damaged *** such as frequent hashtags,mentions,URLs,and useful images were then extracted and *** relevant tweets,along with useful images,were correlated at the county level with flood depth,distributed disaster aid(damage),and population *** correlations were found between the nine relevant topics and population density but not flood depth and damage,suggesting that more research into the suitability of social media data for disaster impacts modeling is *** results from this study provide baseline information for such efforts in the future.

关键词： Disaster impacts Hurricane Harvey Infrastructure impacts Latent Dirichlet allocation(LDA) Social media analysis Twitter data

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Long-term effects of fire frequency and season on herbaceous vegetation in savannas of the Kruger national Park,South Africa

引用

Journal of Plant Ecology 2013年第1期6卷 71-83页

作者： Melinda D.Smith Brian Wvan Wilgen Catherine E.Burns navashni govender Andre L.F.Potgieter Sandy Andelman Harry C.Biggs Judith Botha Winston S.W.Trollope Department of Ecology and Evolutionary Biology Yale UniversityPO Box 208106New HavenCT 06520USA Centre for Invasion Biology Council for Scientific and Industrial Research Natural Resources and the EnvironmentPO Box 320Stellenbosch 7600South Africa north Carolina Chapter Office The Nature Conservancy4705 University DriveSuite 290DurhamNC 27707USA Scientific Services South African National ParksPrivate Bag X402Skukuza 1350South Africa Tropical Ecology Assessment and Monitoring(TEAM)NetworkConservation International2011 Crystal DriveSuite 500ArlingtonVA 22202USA Department of Livestock and Pasture Science University of Fort HarePrivate Bag X1314Alice 5700South Africa

Aims:The long-term effects of changing fire regimes on the herbaceous component of savannas are poorly understood but essential for understanding savanna *** present results from one of the longest running(>44 years)fire experiments in savannas,the experimental burn plots(EBPs),which is located in the Kruger national Park(South Africa)and encompasses four major savanna vegetation types that span broad spatial gradients of rainfall(450–700 mm)and soil ***:Herbaceous vegetation was sampled twice in the EBPs using a modified step-point method,once prior to initiation of the experiment(1954)and again after 44–47 *** combinations of three fire frequency(1-,2-and 3-year return intervals)and five season(before the first spring rains,after the first spring rains,mid-summer,late summer and autumn)treatments,as well as a fire exclusion treatment,were applied at the plot level(;7 ha each),with each treatment(n=12 total)replicated four times at each of the four sites(n=192 plots total).The effects of long-term alterations to the fire regime on grass community structure and composition were analyzed separately for each *** Findings:Over the 44+years duration of the experiment,fires were consistently more intense on sites with higher mean annual rainfall(>570 mm),whereas fires were not as intense or consistent for sites with lower and more variable rainfall(nd potentially higher herbivory due to greater soil *** the plots were open to grazing,the impacts of herbivory along with more variable rainfall regimes likely minimized the effects of fire for the more arid *** a consequence,fire effects on grass community structure and composition were most marked for the higher rainfall sites and generally not significant for the more arid *** the high-rainfall sites,frequent dry season fires(1-to 3-year return intervals)resulted in high grass richness,evenness and diversity,whereas fire exclusion and growing se

关键词： climate fire intensity grass herbivory soil fertility

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatitis E virus: Western Cape, South Africa

引用

World Journal of Gastroenterology 2016年第44期22卷 9853-9859页

作者： Richie G Madden Sebastian Wallace Mark Sonderup Stephen Korsman Tawanda Chivese Bronwyn Gavine Aniefiok Edem Roxy govender nathan English Christy Kaiyamo Odelia Lutchman Annemiek A van der Eijk Suzan D Pas Glynn W Webb Joanne Palmer Elizabeth Goddard Sean Wasserman Harry R Dalton C Wendy Spearman Royal Cornwall Hospital Trust and European Centre for Environment and Human Health University of Exeter Division of Hepatology Department of Medicine Faculty of Health Sciences University of Cape Town and Groote Schuur Hospital national Health Laboratory Service Groote Schuur Hospital Cape Town and Division of Medical Virology University of Cape Town Faculty of Health Sciences Department of Viroscience Erasmus Medical Centre Medical Center Rotterdam Department of Paediatrics Faculty of Health Sciences University of Cape Town and Red Cross Children’s Hospital Division of Infectious Diseases and HIV Medicine Department of Medicine Faculty of Health Sciences University of Cape Town and Groote Schuur Hospital

AIM To conduct a prospective assessment of anti-hepatitis E virus(HEV) Ig G seroprevalence in the Western Cape Province of South Africa in conjunction with evaluating risk factors for *** Consenting participants attending clinics and wards of Groote Schuur, Red Cross Children's Hospital and their affiliated teaching hospitals in Cape Town, South Africa, were sampled. Healthy adults attending blood donor clinics were also recruited. Patients with known liver disease were excluded and all major ethnic/race groups were included to broadly represent local demographics. Relevant demographic data was captured at the time of sampling using an interviewer-administered confidential questionnaire. Human immunodeficiency virus(HIV) status was self-disclosed. HEV Ig G testing was performed using the Wantai? *** HEV is endemic in the region with a seroprevalence of 27.9%(n = 324/1161) 95%CI: 25.3%-30.5%(21.9% when age-adjusted) with no significant differences between ethnic groups or HIV status. Seroprevalence in children is low but rapidly increases in early adulthood. With univariate analysis, age ≥ 30 years old, pork and bacon/ham consumption suggested risk. In the multivariate analysis, the highest risk factor for HEV Ig G seropositivity(OR = 7.679, 95%CI: 5.38-10.96, P ng 30 years or older followed by pork consumption(OR = 2.052, 95%CI: 1.39-3.03, P nt clinical case demonstrates that HEV genotype 3 may be currently circulating in the Western *** Hepatitis E seroprevalence was considerably higher than previously thought suggesting that hepatitis E warrants consideration in any patient presenting with an unexplained hepatitis in the Western Cape, irrespective of travel history, age or ethnicity.

关键词： Hepatitis E Seroprevalence South Africa Pork consumption Genotype

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Performance and calibration of quark/gluon-jet taggers using 140 fb^(-1) of pp collisions at √s=13 TeV with the ATLAS detector

引用

Chinese Physics C 2024年第2期48卷 1-25页

作者： G. Aad B. Abbott K. Abeling n.J. Abicht S.H. Abidi A. Aboulhorma H. Abramowicz H. Abreu Y. Abulaiti B.S. Acharya C. Adam Bourdarios L. Adamczyk S.V. Addepalli M.J. Addison J. Adelman A. Adiguzel T. Adye A.A. Affolder Y. Afik M.n. Agaras J. Agarwala A. Aggarwal C. Agheorghiesei A. Ahmad F. Ahmadov W.S. Ahmed S. Ahuja X. Ai G. Aielli A. Aikot M. Ait Tamlihat B. Aitbenchikh I. Aizenberg M. Akbiyik T.P.A. Åkesson A.V. Akimov D. Akiyama n.n. Akolkar K. Al Khoury G.L. Alberghi J. Albert P. Albicocco G.L. Albouy S. Alderweireldt M. Aleksa I.n. Aleksandrov C. Alexa T. Alexopoulos F. Alfonsi M. Algren M. Alhroob B. Ali H.M.J. Ali S. Ali S.W. Alibocus M. Aliev G. Alimonti W. Alkakhi C. Allaire B.M.M. Allbrooke J.F. Allen C.A. Allendes Flores P.P. Allport A. Aloisio F. Alonso C. Alpigiani M. Alvarez Estevez A. Alvarez Fernandez M. Alves Cardoso M.G. Alviggi M. Aly Y. Amaral Coutinho A. Ambler C. Amelung M. Amerl C.G. Ames D. Amidei S.P. Amor Dos Santos K.R. Amos V. Ananiev C. Anastopoulos T. Andeen J.K. Anders S.Y. Andrean A. Andreazza S. Angelidakis A. Angerami A.V. Anisenkov A. Annovi C. Antel M.T. Anthony E. Antipov M. Antonelli F. Anulli M. Aoki T. Aoki J.A. Aparisi Pozo M.A. Aparo L. Aperio Bella C. Appelt A. Apyan n. Aranzabal S.J. Arbiol Val C. Arcangeletti A.T.H. Arce E. Arena J-F. Arguin S. Argyropoulos J.-H. Arling O. Arnaez H. Arnold G. Artoni H. Asada K. Asai S. Asai n.A. Asbah J. Assahsah K. Assamagan R. Astalos S. Atashi R.J. Atkin M. Atkinson H. Atmani P.A. Atmasiddha K. Augsten S. Auricchio A.D. Auriol V.A. Austrup G. Avolio K. Axiotis G. Azuelos D. Babal H. Bachacou K. Bachas A. Bachiu F. Backman A. Badea P. Bagnaia M. Bahmani A.J. Bailey V.R. Bailey J.T. Baines L. Baines O.K. Baker E. Bakos D. Bakshi Gupta V. Balakrishnan R. Balasubramanian E.M. Baldin P. Balek E. Ballabene F. Balli L.M. Baltes W.K. Balunas J. Balz E. Banas M. Bandieramonte A. Bandyopadhyay S. Bansal L. Barak M. Barakat E.L. Barberio D. Barberis M. Barbero M.Z. Barel K.n. Barends T. Barillari M-S. Barisits T. Barklow P. Baron D.A. Baron Mo The ATLAS Collaboration

The identification of jets originating from quarks and gluons,often referred to as quark/gluon tagging,plays an important role in various analyses performed at the Large Hadron Collider,as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced *** paper describes the measurement of the efficiencies of quark/gluon taggers developed within the ATLAS Collaboration,using √s=13 TeV proton–proton collision data with an integrated luminosity of 140 fb^(-1) collected by the ATLAS *** taggers with high performances in rejecting jets from gluon over jets from quarks are studied:one tagger is based on requirements on the number of inner-detector tracks associated with the jet,and the other combines several jet substructure observables using a boosted decision tree.A method is established to determine the quark/gluon fraction in data,by using quark/gluon-enriched subsamples defined by the jet *** in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points.

关键词： ATLAS JET QUARK GLUOn TAGGInG

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

晚期口腔和口咽恶性肿瘤治疗后影响吞咽的因素

引用

中国口腔颌面外科杂志 2013年第3期 198-198页

作者： Kalavrezos n Cotrufo S govender R

口腔及口咽肿瘤治疗后往往对吞咽功能造成影响,术后口腔进食能力与手术和患者相关因素有关。晚期口腔及口咽癌术后接受或不接受化放疗的114例患者,记录临床病理参数和重建方式。采用口腔进食功能评分(FOIS)对治疗前、后的数据进行比较... 详细信息

口腔及口咽肿瘤治疗后往往对吞咽功能造成影响,术后口腔进食能力与手术和患者相关因素有关。晚期口腔及口咽癌术后接受或不接受化放疗的114例患者,记录临床病理参数和重建方式。采用口腔进食功能评分(FOIS)对治疗前、后的数据进行比较。结果:首次获得吞咽功能的平均时间为14 d。

关键词：口腔吞咽功能

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：