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481.
482.
Henry F. Enos 《Journal of environmental science and health. Part. B》2013,48(6):1059-1070
Abstract The importance of quality control procedures to the collection of pesticide residue data is discussed. The equipment requirements of an adequate, safe pesticide residue laboratory are presented. Equipment maintenance, personnel training, and preservation of samples is also reviewed. Appropriate objectives for an intra‐laboratory quality control program are outlined. 相似文献
483.
484.
L. A. James Valverde Jr. Henry D. Jacoby Gordon M. Kaufman 《Environmental Modeling and Assessment》1999,4(2-3):87-101
We develop an integrated framework for evaluating sequential greenhouse gas abatement policies under uncertainty. The analysis integrates information concerning the magnitude, timing, and impacts of climate change with data on the likely effectiveness and cost of possible response options. Reduced-scale representations of the global climate system, drawn from the MIT Integrated Global System Model, form the empirical basis of the analysis. The method is illustrated in application to emissions control policies of the form considered under the United Nations Framework Convention on Climate Change. 相似文献
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487.
Henry P. Huntington Lawrence C. Hamilton Craig Nicolson Ronald Brunner Amanda Lynch Astrid E. J. Ogilvie Alexey Voinov 《Regional Environmental Change》2007,7(4):173-186
Human dimensions research focuses on the interrelationships between humans and the environment. To date, human dimensions
research in arctic regions has concentrated primarily on local events and contexts. As such, it complements analysis elsewhere
of adaptation and sustainable development within broad institutional, social, and environmental contexts. This paper reviews
five projects from the Human Dimensions of the Arctic System (HARC) initiative, established by the US National Science Foundation
in 1997. Common themes and findings are highlighted: climatic variations or change affect societies through interactions with
human activities; population dynamics provide key quantitative indicators of social impacts and well being; and specific impacts
and responses are the result of complex, context-sensitive interactions. Congruent approaches to the challenges of interdisciplinary
research are also identified: multivariate time plots aid the integration of data, retrospective and prospective studies are
part of a continuum and reinforce one another, comparative studies are essential for understanding general principles of human
dimensions, and arctic residents can play a vital role in research and action. 相似文献
488.
Processing of allochthonous macrophyte subsidies by sandy beach consumers: estimates of feeding rates and impacts on food resources 总被引:1,自引:0,他引:1
Mariano Lastra Henry M. Page Jenifer E. Dugan David M. Hubbard Ivan F. Rodil 《Marine Biology》2008,154(1):163-174
Allochthonous subsidies of organic material can profoundly influence population and community structure; however, the role
of consumers in the processing of these inputs is less understood but may be closely linked to community and ecosystem function.
Inputs of drift macrophytes subsidize sandy beach communities and food webs in many regions. We estimated feeding rates of
dominant sandy beach consumers, the talitrid amphipods (Megalorchestia corniculata, in southern California, USA, and Talitrus saltator, in southern Galicia, Spain), and their impacts on drift macrophyte subsidies in field and laboratory experiments. Feeding
rate varied with macrophyte type and, for T. saltator, air temperature. Size-specific feeding rates of talitrid amphipods were greatest on brown macroalgae (Macrocystis, Egregia, Saccorhiza and Fucus). Rates for large individuals of both species ranged from ∼40 mg wet wt individual−112 h−1 on brown macroalgae to negligible feeding by M. corniculata on a vascular plant (surfgrass). Amphipod growth rates were also greatest on Macrocystis and lowest on surfgrass, Phyllospadix. For a Californian beach with substantial inputs of macrophyte wrack (>70 kg wet wt m−1 month−1 in summer), we estimated that the population of talitrid amphipods could process an average of 55% of the palatable Macrocystis input. Our results indicate that talitrid amphipod populations can have a significant impact on drift macrophyte processing
and fate and that the quantity and composition of drift macrophytes could, in turn, limit populations of beach consumers. 相似文献
489.
Graham Heaslip Alain Vaillancourt Peter Tatham Gyngyi Kovcs Deborah Blackman Marian Crowley Henry 《Disasters》2019,43(3):686-708
The continuing incidence of disasters and their associated challenges has increased the demand for humanitarian logisticians. However, there is a dearth of research on their essential competencies. This paper proposes, therefore, a humanitarian logistics competency framework (HlCF) to assist with the professional development of humanitarian logisticians. In creating the HlCF, nine competency domains containing 29 specific competencies across four levels (entry to senior management) were identified. This study makes two key contributions to the literature: (i) it extends the discussion of competency frameworks in humanitarian logistics; and (ii) it presents a framework designed to support the human resource plans and practices of aid agencies. The HlCF allows not only individual humanitarian logisticians to develop the competencies necessary for career success, but also humanitarian organisations to map their own competency frameworks to a common standard. This will, in turn, facilitate workforce mobility and support the overall concept of a certified humanitarian logistics professional. 相似文献
490.
Episodic death across species of desert shrubs 总被引:2,自引:0,他引:2
Extreme events shape population and community trajectories. We report episodic mortality across common species of thousands of long-lived perennials individually tagged and monitored for 20 years in the Colorado Desert of California following severe regional drought. Demographic records from 1984 to 2004 show 15 years of virtual stasis in populations of adult shrubs and cacti, punctuated by a 55-100% die-off of six of the seven most common perennial species. In this episode, adults that experienced reduced growth in a lesser drought during 1984-1989 failed to survive the drought of 2002. The significance of this event is potentially profound because population dynamics of long-lived plants can be far more strongly affected by deaths of adults, which in deserts potentially live for centuries, than by seedling births or deaths. Differential mortality and rates of recovery during and after extreme climatic events quite likely determine the species composition of plant and associated animal communities for at least decades. The die-off recorded in this closely monitored community provides a unique window into the mechanics of this process of species decline and replacement. 相似文献