检索结果-南通市图书馆

Analyzing short time series data from periodically fluctuating rodent populations by thresholdmodels: A nearest block bootstrap approach

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2009年第6期52卷 1085-1106页

作者： CHAN Kung-Sik TONG Howell STENSETH Nils chr Department of Statistics and Actuarial Science The University of IowaIowa CityIA 52242USA Department of Statistics London School of Economics & the University of Hong KongHong KongChina Centre for Ecological and Evolutionary Synthesis(CEES) Department of BiologyUniversity of OsloP.O.Box 1066 BlindernN-0316 OsloNorway

The study of the rodent fluctuations of the North was initiated in its modern form with Elton's pioneering work.Many scientific studies have been designed to collect yearly rodent abundance data,but the resulting time series are generally subject to at least two "problems":being short and non-linear.We explore the use of the continuous threshold autoregressive(TAr) models for analyzing such data.In the simplest case,the continuous TAr models are additive autoregressive models,being piecewise linear in one lag,and linear in all other lags.The location of the slope change is called the threshold parameter.The continuous TAr models for rodent abundance data can be derived from a general prey-predator model under some simplifying assumptions.The lag in which the threshold is located sheds important insights on the structure of the prey-predator system.We propose to assess the uncertainty on the location of the threshold via a new bootstrap called the nearest block bootstrap(NBB) which combines the methods of moving block bootstrap and the nearest neighbor bootstrap.The NBB assumes an underlying finite-order time-homogeneous Markov process.Essentially,the NBB bootstraps blocks of random block sizes,with each block being drawn from a non-parametric estimate of the future distribution given the realized past bootstrap series.We illustrate the methods by simulations and on a particular rodent abundance time series from Kilpisjrvi,Northern Finland.

关键词： AIC continuous threshold autoregressive model non-nested hypotheses partial residual plots

Contrasting phenology responses to climate warming across the northern extra-tropics

在线全文

学校读者我要写书评

暂无评论

Fundamental research 2022年第5期2卷 708-715页

作者： Xiaojun Geng Yaru Zhang Yongshuo H.Fu Fanghua Hao Ivan A.Janssens Josep penuelas Shilong piao Jing Tang Zhaofei Wu Jing Zhang Xuan Zhang Nils chr.Stenseth College of Water Sciences Beijing Normal UniversityBeijing 100875China General Institute of Water resources and Hydropower planning and Design(GIWp) Ministry of Water ResourcesBeijing 100053China plants and Ecosystems Department of BiologyUniversity of AntwerpAntwerpBelgium CrEAF Cerdanyola del VallèsBarcelona 08193CataloniaSpain CSIC Global Ecology Unit CREAF-CSIC-UABBellaterraBarcelona 08193CataloniaSpain pecking University Beijing100847China Department of physical Geography and Ecosystem Science Lund UniversitySE22362 LundSweden Terrestrial Ecology Section Department of BiologyUniversity of CopenhagenDK2100CopenhagenDenmark Center for permafrost(CENpErM) University of CopenhagenDK1350CopenhagenDenmark Centre for Ecological and Evolutionary Synthesis(CEES) Department of BiosciencesUniversity of OsloN-0316 OsloNorway

Climate warming has substantially advanced the timing of spring leaf-out of woody species at middle and high latitudes,albeit with large differences.Insights in the spatial variation of this climate warming response may therefore help to constrain future trends in leaf-out and its impact on energy,water and carbon balances at global scales.In this study,we used in situ phenology observations of 38 species from 2067 study sites,distributed across the northern hemisphere in China,Europe and the United States,to investigate the latitudinal patterns of spring leaf-out and its sensitivity(S T,advance of leaf-out dates per degree of warming)and correlation(r_(T),partial correlation coefficient)to temperature during the period 1980-2016.Across all species and sites,we found that S_(T) decreased significantly by 0.15±0.02 d℃^(-1)°N^(-1),and r_(T) increased by 0.02±0.001°N^(-1)(both at ppatterns in r_(T) and S_(T) were explained by the differences in requirements of chilling and thermal forcing that evolved to maximize tree fitness under local climate,particularly climate predictability and summed precipitation during the pre-leaf-out season.Our results thus showed complicated spatial differences in leaf-out responses to ongoing climate warming and indicated that spatial differences in the interactions among environmental cues need to be embedded into large-scale phenology models to improve the simulation accuracy.

关键词： Apparent temperature sensitivity Latitudinal pattern Leaf-out Temperate tree Climate change

Ecometrics:The traits that bind the past and present together

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2010年第2期5卷 88-101页

作者： Jussi T.ErONEN p.David pOLLY Marianne FrED John DAMUTH David C.FrANK Volker MOSBrUGGEr christoph SCHEIDEGGEr Nils chr.STENSETH Mikael FOrTELIUS Department of Geosciences and Geography Helsinki UniversityFinland Department of Geological Sciences Indiana UniversityUSA ArONIA research Institute atÅbo Akademi University and Novia University of Applied SciencesCoastal Zone Research TeamEkenäFinland Department of Ecology Evolution and Marine BiologyUniversity of CaliforniaSanta BarbaraCaliforniaUSA Swiss Federal research Institute WSL BirmensdorfSwitzerland Senckenberg Natural History Museum and research Institute FrankfurtGermany Centre for Ecological and Evolutionary Synthesis(CEES) Department of BiologyUniversity of OsloOsloNorway

We outline here an approach for understanding the biology of climate change,one that integrates data at multiple spatial and temporal scales.Taxon-free trait analysis,or“ecometrics,”is based on the idea that the distribution in a community of ecomorphological traits such as tooth structure,limb proportions,body mass,leaf shape,incubation temperature,claw shape,any aspect of anatomy or physiology can be measured across some subset of the organisms in a community.regardless of temporal or spatial scale,traits are the means by which organisms interact with their environment,biotic and abiotic.Ecometrics measures these interactions by focusing on traits which are easily measurable,whose structure is closely related to their function,and whose function interacts directly with local environment.Ecometric trait distributions are thus a comparatively universal metric for exploring systems dynamics at all scales.The main challenge now is to move beyond investigating how future climate change will affect the distribution of organisms and how it will impact ecosystem services and to shift the perspective to ask how biotic systems interact with changing climate in general,and how climate change affects the interactions within and between the components of the whole biotic-physical system.We believe that it is possible to provide believable,quantitative answers to these questions.Because of this we have initiated an IUBS program iCCB(integrative Climate Change Biology).

关键词： community structure ecometrics integrative Climate Change Biology Taxon-free trait distribution

Obstetric Emergencies at the Kara University Hospital Maternity Ward: Sociodemographic, Etiological and prognostic Aspects

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Obstetrics and Gynecology 2024年第1期14卷 69-76页

作者： Logbo-Akey Kossi Edem Bassowa Akila Ketevi Tina Kambote Yendoubé patchidi Kibandou Amewouho Kofi Ajavon Dédé régina Aboubakari Abdoul-samadou Service de Gynécologie-Obstétrique CHU Kara Université de Kara Kara Togo Service de Gynécologie-Obstétrique CHU Campus Université de Lomé Lomé Togo Service de Gynécologie-Obstétrique CHU Sylvanus Olympio Université de Lomé Togo Faculté des sciences de la santé Université de Lomé Lomé Togo Service de Gynécologie-Obstétrique CHR Tomdé Université de Kara Togo

Introduction: Obstetric emergencies are common throughout the world and more particularly in developing countries where they are responsible for high maternal-fetal mortality and morbidity. Objective: Study obstetric emergencies in the maternity ward of Kara University Hospital. Method: retrospective and descriptive study from April 1, 2022 to March 30, 2023, carried out in the Obstetrics and Gynecology Department of Kara University Hospital. results: Eight hundred and thirty-five (835) obstetric emergencies were recorded out of 2215 admissions, i.e. a frequency of 37.7%. The average age of the patients was 26.7 with a range of 14 and 45 years. They were primigravidas (36.7%) and nulliparous (38.7%), referred (84.7%) and came from rural areas (72%). Emergencies occurred in the 3p>rdp> trimester in 74.1% and in parturients (54.1%). preeclampsia (27%), cessation of progression of labor due to feto-pelvic disproportion (12.4%), postpartum hemorrhage (7.5%) constituted the main obstetric emergencies. In 44.8%, the delivery was carried out vaginally. Magnesium sulfate was the most used drug, i.e. 30.1%;followed by antihypertensive medications in 28.1%. Blood transfusion was performed in 24.3%. The evolution was simple in 90.9%. The maternal fatality rate was 1.6%. The perinatal case fatality rate was 12.3%. Conclusion: Obstetric emergencies are common, dominated by preeclampsia, stopping progress of labor and postpartum hemorrhages. They are responsible for high morbidity and mortality.

关键词： Obstetric Emergency Kara University Hospital

Diversity of arbuscular mycorrhizal fungi associated with desert ephemerals growing under and beyond the canopies of Tamarisk shrubs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2006年第A1期51卷 132-139页

作者： SHI Zhaoyong ZHANG Liyun FENG Gu chr stie peter TIAN Changyan LI Xiaolin Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China College of resources and Environmental Sciences China Agricultural University Beijing 100094 China Agricultural and Environmental Science Department Queen's University Belfast Belfast BT9 PX UK

arbuscular mycorrhizal (AM ) 四很普通的短暂植物种的真菌的地位， Chorispora tenella (棺罩) DC， Cerato-cephalus testiculatus (Crantz ) 贝丝， Eremopyrum 面向(L) Jaub et Spash 和在树柳属植物灌木(Tamarix spp ) 统治的一个区域成长的维朗妮卡 campy-lopoda Boiss 被调查。四 ephemerals 和他们的根围土壤的样品从在下面并且在 Tamariskshrubs 的华盖以外被收集。植物 mycorrhizal 地位和土壤 AM 真菌的孢子密度和社区结构被分析并且比较在下面并且在灌木华盖以外。在他们的相应根围土壤的 ephemerals 和孢子密度的 mycorrhizal 殖民率在灌木华盖下面是显著地更低的比在远处。在灌木(12 ) 下面的 AM 真菌的种类的数字也比在华盖(19 ) 以外低。什么时候在四 ephemerals 的根围玷污性质，被检验的、可得到的 N 和 p 和全部的 p，有机物内容，全部的盐内容和电的电导率(EC ) 都在华盖下面是更高的比在远处。相反，玷污显示出的可得到的 K 和酸碱值没有如此的趋势。上午 21 点的一个总数真菌的种类从四 ephemerals 的根围土壤被孤立。五属于 Acaulospora，到 Archaeo-spora， 13 到血管球并且二到 paraglomus。我们得出结论 Tamarix spp 的华盖。对 ephemerals 的 AM 地位并且在 AM 真菌的社区和一些他们的根围土壤的性质上施加了一些影响。

关键词：灌木真菌短生植物树冠撑柳

城市污水生物处理系统中微生物酶的活性及其分布

在线全文

学校读者我要写书评

暂无评论

环境污染与防治 2007年第5期29卷 333-335页

作者：李茵罗翠 chróst r J 东华大学环境科学与工程学院上海201620 华沙大学生物学院

通过水解模式底物进行分光光度测定的方法，研究了城市污水生物处理系统中微生物酶的活性。选取亮氨酸氨基肽酶、β-葡萄糖苷酶、碱性磷酸酶和脂酶等胞外酶进行分析，结果发现4种胞外酶的平均活性在31．0～88．5μmol／（L·h），其中76... 详细信息

通过水解模式底物进行分光光度测定的方法，研究了城市污水生物处理系统中微生物酶的活性。选取亮氨酸氨基肽酶、β-葡萄糖苷酶、碱性磷酸酶和脂酶等胞外酶进行分析，结果发现4种胞外酶的平均活性在31．0～88．5μmol／（L·h），其中76．9％～94．8％的酶活性分布在活性污泥中，说明绝大部分胞外酶是与细胞相连或固定在细胞外多聚絮体基质里。混合水样和出水水样中的Doc几乎相等，而各胞外酶与DOC不存在任何显著的相关关系。增加NO3^-浓度可提高亮氨酸氨基肽酶和β-葡萄糖苷酶的活件．伯对碱件磷酸酶和脂酶却右明显的抑制作用。

关键词：酶活性胞外酶活性污泥城市污水

Obstetric references in Disadvantaged Environments: Case of references to the University Hospital Center of Kara, in Northern Togo

在线全文

学校读者我要写书评

暂无评论

Open Journal of Obstetrics and Gynecology 2024年第2期14卷 267-277页

作者： Kossi Edem Logbo-Akey Bassowa Akila Kofi Mawoulé Améwouho Ketevi Tina Yendoubé pierre Kambote Dédé régine Diane Ajavon Baguilane Djoauguibe Abdoul-samadou Aboubakari Koffi Akpadza Service de Gynécologie-Obstétrique CHU Kara Togo Service de Gynécologie-Obstétrique CHU Campus Lomé Togo Service de Gynécologie-Obstétrique CHU Sylvanus Olympio Lomé Togo Service de Gynécologie-Obstétrique CHR Tomdé Kara Togo

Introduction: references are frequent and most often carried out in emergency situations. The objective of this study was to describe the epidemiological and clinical profile of obstetric referrals to the CHU-Kara. Methodology: This was a retrospective cross-sectional descriptive study conducted from September 1, 2022, to February 28, 2023, at CHU-Kara, focusing on obstetric referrals to the Gynecology-Obstetrics department. result: 828 patients were referred for obstetric reasons out of 1295 admissions, representing a frequency of 63.9%. The average age was 25.04 years. They were primigravida (38.3%), unemployed (62.7%). Motorcycles were the main means of transportation, accounting for 53.1% of cases. The average distance to reach the referral center was 31.6 km, covered in an average of 71 minutes. In 40.7% of cases, patients had less than 4 prenatal consultations and were referred in peripartum (56.6%) for pre-eclampsia (14%), post-term pregnancy (11.8%), dystocia (10.5%). Eighty-six point nine percent (86.9%) of the referred patients were able to deliver during their stay in the department, of which 61.7% had vaginal deliveries. The maternal and perinatal mortality rates were 0.7% and 14.9%, respectively. Conclusion: Obstetric referrals to Kara University Hospital are frequent during the perpartum period and are often carried out by motorbike.

关键词： Obstetric referral Epidemiology prognosis CHU-Kara

“畸变工程”:从系统的角度探讨零件的畸变现象

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

金属热处理 2004年第11期29卷 43-50页

作者： Klaus-DieterThoben DieterKlein Th.Luebben B.Clausen chr.prinz A.Schulz r.rentsch r.Kusmierz L.Nowag H.Surm F.Frerichs M.Hunkel p.Mayr BremenInstituteofIndustrialTechnologyandAppliedWorkScience（BIBA） BremenGermany InstituteforMaterialScience（IWT） BremenGermany

在产品的最终加工过程中用精磨去除零件中的畸变是一个既费钱又费时的事情。例如 ,仅在 (车辆 )传动技术领域 ,1995年德国用于最后精磨以消除工件的畸变而增加的成本已达 8 5亿欧元。迄今为止 ,行业人士认为在最后的产品加工过程中导致... 详细信息

在产品的最终加工过程中用精磨去除零件中的畸变是一个既费钱又费时的事情。例如 ,仅在 (车辆 )传动技术领域 ,1995年德国用于最后精磨以消除工件的畸变而增加的成本已达 8 5亿欧元。迄今为止 ,行业人士认为在最后的产品加工过程中导致零件产生畸变的主要原因在于淬火过程 ,而今大家普遍认为这个观点不是很对 ,认为淬火过程只是释放了在各个加工环节中积累在工件中的畸变潜能 ,如铸造、车削加工、铣削、淬火、磨削。由不来梅大学创立及DeutscheForschungsgemeinschaft资助的合作研究中心SFB 5 70“畸变工程”的研究方针是从系统导向着手 ,分析零件的畸变。合作研究中心由 12个子项目组成 ,涉及 2 0多位来自材料科学、制造技术、数学及过程控制工程的研究人员。根据系统导向的方法 ,合作研究中心SFB 5 70“畸变工程”认为 ,与优化零件整个生产过程 (工序链 )相比 ,对零件生产过程中的单个过程的优化是第二位的。为了推广系统导向的方法 ,保证SFB 5 70“畸变工程”中集中在不同工序和技术的这 12个子项目间的一个连续、协调的知识和信息交换 ,已成立了一个系统模式工作组。这个工作组的焦点在于详细阐述和进一步发展系统导向的方法以及协调应用于这些子项目中的工序和方法。和其它方法相比较 ,整体方法包?

关键词：变现工程项目系统欧元协调行业导向潜能数学

在线全文

学校读者我要写书评

暂无评论

家禽红螨(鸡皮刺螨)的意义及防治

养禽与禽病防治 2024年第4期 25-40页

作者： O.A.E.Sparagano D.r.George D.WJ.Harrington A.Giangaspero 刘红(校对) Faculty of Health and Life Sciences Northumbria UniversityNewcastle upon Tyne NE18STUnited Kingdom poultry Division Chr.Hansen A/S2970 HorsholmDenmark Dipartimento di Scienze Agrarie degli Alimenti e dell'AmbienteUniversita di Foggia71121Italy 默沙东动物保健品(上海)有限公司

家禽红螨(鸡皮刺螨)严重威胁世界各地的家禽生产和母鸡健康。鸡皮刺螨不但逐渐被认为是疫病重要的载体,而且有越来越多的报告显示其还可攻击包括人类在内的其他宿主,可见这种害虫对经济的影响变得越来越严重。随着世界各地的家禽生产逐... 详细信息

家禽红螨(鸡皮刺螨)严重威胁世界各地的家禽生产和母鸡健康。鸡皮刺螨不但逐渐被认为是疫病重要的载体,而且有越来越多的报告显示其还可攻击包括人类在内的其他宿主,可见这种害虫对经济的影响变得越来越严重。随着世界各地的家禽生产逐渐脱离传统的笼养方式,鸡皮刺螨在禽群中的影响将变得更加普遍,防控将变得更加困难。尽管已有耐药性和治疗失败的报告,但鸡皮刺螨的防治仍以合成杀螨剂为主。目前在鸡皮刺螨及螨虫管理的专项研究报告中已经提出一些替代防治措施。尽管许多替代防治措施仍处于商业化前期阶段,但仍有部分措施已经逐渐进入市场。本综述汇集了日益扩充的鸡皮刺螨的研究,并评估了其当前和未来可供选择的防控措施。得出的结论是,鸡皮刺螨防治的重大进展最有可能来自综合防控的措施,将最新的研究融入到现有的和新型的防治策略中,这种融合将改进的监测和建模相结合,更好地为治疗和干预该病提供信息支持。

关键词：鸡母鸡体外寄生虫兽医害虫防治