检索结果-南通市图书馆

Climate refugia along Lake Superior’s shores:disjunct arctic-alpine plants rely on cool shoreline temperatures but are restricted to highly exposed habitat under climate warming

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2024年第4期17卷 23-41页

作者： Ashley Hillman Scott E.nielsen Department of Renewable Resources University of AlbertaEdmontonAB T6G 2R3Canada

Climate refugia can serve as a remnant habitat or stepping stones for species dispersal under climate *** largest freshwater lake by surface area,Lake Superior,USA and Canada,serves as a model system for understanding cooling-mediated local refugia,as its cool water temperatures and wave action have maintained shoreline habitats suitable for southern disjunct populations of arctic-alpine plants since ***,we seek to explain spatial patterns and environmental drivers of arctic-alpine plant refugia along Lake Superior’s shores,and assess future risk to refugia under moderate(+3.5℃)and warmest(+5.7℃)climate warming ***,we examined how the interactive effects of summer surface water temperatures and wind affected onshore temperatures,resulting in areas of cooler ***,we developed an ecological niche model for the presence of disjunct arctic-alpine refugia(pooling 1253 occurrences from 58 species)along the lake’s ***,we fit species distribution models for 20 of the most common arctic-alpine disjunct species and predicted presence to identify refugia ***,we used the two climate warming scenarios to predict changes in the presence of refugia and disjunct *** type,elevation above water,inland distance,July land surface temperature from MODIS/Terra satellite and near-shore depth of water were the best predictors of disjunct ***,we predicted 2236 km of the shoreline(51%)as disjunct refugia habitat for at least one species under current conditions,but this was reduced to 20% and 7% with moderate(894 km)and warmest(313 km)climate change projections.

关键词： climate refugia disjunct populations lake effect Lake Superior species distribution models

Transmission matrices used in epidemiologic modelling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Infectious Disease Modelling 2024年第1期9卷 185-194页

作者： M.Bekker-nielsen Dunbar Centre for Research on Pandemics&Society OsloMet–Oslo Metropolitan UniversityHG536Holbergs gate 1Oslo0166Norway

Mixing matrices are included in infectious disease models to reflect transmission opportunities between population *** matrices were originally constructed on the basis of theoretical considerations and most of the early work in this area originates from research on sexually transferred diseases in the 80s,in response to *** work in the 90s populated these matrices on the basis of survey data gathered to capture transmission risks for respiratory *** provide an overview of developments in the construction of matrices for capturing transmission opportunities in *** transmission matrices are useful for epidemiologic modelling to capture within and between stratum transmission and can be informed from theoretical mixing assumptions,informed by empirical evidence gathered through investigation as well as generated on the basis of *** to summary measures and threshold conditions are also provided.

关键词： Disease transmission Mixing matrix Social contact Index of disassortativity

Influence of railway wheel tread damage on wheel-rail impact loads and the durability of wheelsets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Railway Engineering Science 2024年第1期32卷 20-35页

作者： Michele Maglio Tore Vernersson Jens C.O.nielsen Anders Ekberg Elena Kabo CHARMEC Department of Mechanical and Maritime SciencesChalmers University of TechnologySE‑41296 GothenburgSweden

Dynamic wheel-rail contact forces induced by a severe form of wheel tread damage have been measured by a wheel impact load detector during full-scale field tests at different vehicle *** on laser scanning,the measured three-dimensional damage geometry is employed in simulations of dynamic vehicle-track interaction to calibrate and verify a simulation *** relation between the magnitude of the impact load and various operational parameters,such as vehicle speed,lateral position of wheel-rail contact,track stiffness and position of impact within a sleeper bay,is *** calibrated model is later employed in simulations featuring other forms of tread damage;their effects on impact load and subsequent fatigue impact on bearings,wheel webs and subsurface initiated rolling contact fatigue of the wheel tread are *** results quantify the effects of wheel tread defects and are valuable in a shift towards condition-based maintenance of running gear,and for general assessment of the severity of different types of railway wheel tread damage.

关键词： Wheel tread damage Rolling contact fatigue cluster Field measurements Dynamic vehicle-track interaction Wheel-rail impact load Wheelset durability

Electrogenic sulfur oxidation mediated by cable bacteria and its ecological effects

在线全文

学校读者我要写书评

暂无评论

Environmental Science and Ecotechnology 2024年第4期20卷 34-41页

作者： Zhenyu Wang Leonid Digel Yongqiang Yuan Hui Lu Yonggang Yang Carsten Vogt Hans-Hermann Richnow Lars Peter nielsen Department of Isotope Biogeochemistry Helmholtz Centre for Environmental Research e UFZPermoserstraße 1504318LeipzigGermany Center for Electromicrobiology Department of BiologyAarhus UniversityDK-8000AarhusDenmark Key Laboratory of Karst Georesources and Environment Ministry of EducationCollege of Resources and Environmental EngineeringGuizhou UniversityGuiyang550025China School of Environmental Science and Engineering Sun Yat-Sen UniversityGuangzhou510006China School of Life Science and Engineering Foshan UniversityFoshan528225China State Key Laboratory of Applied Microbiology Southern China Institute of MicrobiologyGuangdong Academy of SciencesGuangzhou510007China

At the sediment-water interfaces,filamentous cable bacteria transport electrons from sulfide oxidation along their filaments towards oxygen or nitrate as electron *** multicellular bacteria belonging to the family Desulfobulbaceae thus form a biogeobattery that mediates redox processes between multiple *** bacteria were first reported in *** the past years,cable bacteria have been found to be widely distributed across the *** potential in shaping the surface water environments has been extensively studied but is not fully *** this review,the biogeochemical characteristics,conduction mechanisms,and geographical distribution of cable bacteria,as well as their ecological effects,are systematically reviewed and *** insights for understanding and applying the role of cable bacteria in aquatic ecology are summarized.

关键词： Cable bacteria Electrogenic sulfur oxidation Long-distance electron transfer Aquatic ecology

Metabolic collaboration between cells in the tumor microenvironment has a negligible effect on tumor growth

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Innovation 2024年第2期5卷 107-114页

作者： Johan Gustafsson Fariba Roshanzamir Anders Hagnestål Sagar M.Patel Oseeyi I.Daudu Donald F.Becker Jonathan L.Robinson Jens nielsen Department of Life Sciences Chalmers University of TechnologySE-41296 GothenburgSweden Hagnesia AB SE-43854 HindåsSweden Department of Biochemistry and Redox Biology Center University of Nebraska-LincolnLincolnNE 68588USA BioInnovation Institute DK2200 CopenhagenDenmark

The tumor microenvironment is composed of a complex mixture of different cell types interacting under conditions of nutrient deprivation,but the metabolism therein is not fully understood due to difficulties in measuring metabolic fluxes and exchange of metabolites between different cell types in ***-scale metabolic modeling enables estimation of such exchange fluxes as well as an opportunity to gain insight into the metabolic behavior of individual cell ***,we estimated the availability of nutrients and oxygen within the tumor microenvironment using concentration measurements from blood together with a metabolite diffusion *** addition,we developed an approach to efficiently apply enzyme usage constraints in a comprehensive metabolic model of human *** combined modeling reproduced severe hypoxic conditions and the Warburg effect,and we found that limitations in enzymatic capacity contribute to cancer cells’preferential use of glutamine as a substrate to the citric acid ***,we investigated the common hypothesis that some stromal cells are exploited by cancer cells to produce metabolites useful for the cancer *** identified over 200 potential metabolites that could support collaboration between cancer cells and cancer-associated fibroblasts,but when limiting to metabolites previously identified to participate in such collaboration,no growth advantage was *** work highlights the importance of enzymatic capacity limitations for cell behaviors and exemplifies the utility of enzyme-constrained models for accurate prediction of metabolism in cells and tumor microenvironments.

关键词： metabolism effect limitations

Validation and correction of auto-logged position measurements

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 Transportation Research 2022年第1期2卷 1-12页

作者： Angelos Ikonomakis Ulrik Dam nielsen Klaus Kahler Holst jesper Dietz Roberto Galeazzi Maersk R&D CopenhagenDenmark DTU Mechanical Engineering Technical University of DenmarkKgs.LyngbyDenmark Maersk Line Fleet Performance CopenhagenDenmark DTU Electrical Engineering Technical University of DenmarkKgs.LyngbyDenmark Centre for Autonomous Marine Operations and Systems NTNU AMOSTrondheimNorway

Accurate position measurements are extremely valuable in the shipping industry for various reasons such as safety(collision avoidance),security(situational awareness),fuel-saving(weather identification),punctuality(route prediction),*** GNSS(Global Navigation Satellite System)receivers installed on-board the ships are proven to be highly accurate,the data logging process may occasionally be problematic,mainly due to the complexity of the measurements and the decimal precision that is *** were collected from 3 years of operations of 228 Maersk Line container vessels and an analysis reveals that there is a substantial amount (≈20%) of historical position measurements sent to shore that does not reflect *** the study,the sources of the faulty logged position measurements are categorized and an interpolation methodology is proposed to validate and correct them by using AIS(Automatic Identification System)data.

关键词： Linear interpolation GNSS coordinates AIS coordinates Measurement error Sensor accuracy

数字政府缘何生成行政负担?--对丹麦数字ID升级项目的审视

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国行政管理 2024年第4期40卷 93-106页

作者： [丹麦]施雷格任运月杨峰浙江工商大学公共管理学院杭州310018 四川大学公共管理学院成都610064

在世界各国默认数字化进程中,普遍存在数字化减轻民众与政府互动过程中行政负担的乐观期望。然而,审视数字化“最佳实践”国丹麦的数字身份系统升级项目,可以发现各行动者有意无意的利益考量和行为模式反而导致了行政负担的形成和加重... 详细信息

在世界各国默认数字化进程中,普遍存在数字化减轻民众与政府互动过程中行政负担的乐观期望。然而,审视数字化“最佳实践”国丹麦的数字身份系统升级项目,可以发现各行动者有意无意的利益考量和行为模式反而导致了行政负担的形成和加重。个中缘由包括不同行动者角色认知和价值判断差异化的影响,数字技术自身的兼容性难题和可及性障碍产生的自动不平等加重了行政负担分配性,数字政府制度建构过程中工具理性扩张带来的“数字牢笼”潜在风险。因此,有必要从建立良好的行动者关系的角度出发寻求减轻民众行政负担之策,以确保数字政府转型升级的顺利进行,要明确政企合作网络中政府“核心行动者”的角色地位,将数字政府注意力转向改善政府与民众关系。

关键词：行政负担数字政府数字身份政商关系

Multifunctional landscapes—perspectives for the future

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2003年第2期15卷 187-192页

作者： jesper Brandt Department of Geography and International Development Studies Roskilde University

New methods in landscape ecology to study the link between landscape heterogeneity and landscape functionality are needed. Heterogeneity is a basic characteristic of landscape, and landscape function is the capacity to change the structural heterogeneity of a landscape system. In most developed countries the industrialisation of agriculture has in general resulted in a change of agricultural landscapes from a small-grained heterogeneous pattern towards more monotonous and monofunctional landscapes. During the 1990's this trends seems to have changed due to a diversification of rural land use and new trends in urbanisation. Weather these phases of landscape development should be expected in developing countries is a totally open question. Dealing with the study of multifunctionality of landscapes it is proposed to distinguish between ecological functionality of landscape ecosystems, functionality pertaining to land use and social functionality. Further, the relation between function, space and scale is important by the determination of spatial and time segregation as well as spatial and time integration of multifunctionality in landscapes.

关键词： landscape heterogeneity monotonisation multifunctionality spatial segregation time segregation landscape development

Application of heat shock protein expression for detecting natural adaptation and exposure to stress in natural populations

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2010年第6期56卷 703-713页

作者： jesper Givskov SφRENSEN National Environmental Research Institute Aarhus UniversityDepartment of Terrestrial Ecology

Heat-shock proteins （HSPs） play an undisputed role for maintaining cellular functioning under environmental challenges and protein denaturing conditions. Compelling evidence points to an evolutionary important role of HSPs and a strict evolutionary control of these proteins as a balance between benefits and costs. While there is a great potential for using HSP expression for detecting natural adaptation and exposure to stress in natural populations, some obstacles and key issues await investigation. From an ecological perspective these key issues needs to be resolved in order to fully appreciate the complex responses and adaptations to stress and to increase our understanding of HSPs and other molecular chaperones for stress adaptation and potential use as biomarkers. Here, the current knowledge and understanding of HSPs is reviewed and a number of key issues including the interpretation of elevated HSP levels, the complications of extrapolating between laboratory and field conditions, the effects of choice of traits and methodology and the larger intra-and extracellular networks of interactions that HSPs participate in are discussed [Current Zoology 56 （6）： 703-713, 2010].

关键词： Biomarker Hsp Molecular chaperone Thermal adaptation Thermal stress