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31.
Fitzpatrick MC  Preisser EL  Porter A  Elkinton J  Waller LA  Carlin BP  Ellison AM 《Ecology》2010,91(12):3448-55; discussion 3503-14
The study of ecological boundaries and their dynamics is of fundamental importance to much of ecology, biogeography, and evolution. Over the past two decades, boundary analysis (of which wombling is a subfield) has received considerable research attention, resulting in multiple approaches for the quantification of ecological boundaries. Nonetheless, few methods have been developed that can simultaneously (1) analyze spatially homogenized data sets (i.e., areal data in the form of polygons rather than point-reference data); (2) account for spatial structure in these data and uncertainty associated with them; and (3) objectively assign probabilities to boundaries once detected. Here we describe the application of a Bayesian hierarchical framework for boundary detection developed in public health, which addresses these issues but which has seen limited application in ecology. As examples, we analyze simulated spread data and the historic pattern of spread of an invasive species, the hemlock woolly adelgid (Adelges tsugae), using county-level summaries of the year of first reported infestation and several covariates potentially important to influencing the observed spread dynamics. Bayesian areal wombling is a promising approach for analyzing ecological boundaries and dynamics related to changes in the distributions of native and invasive species.  相似文献   
32.
US government actions undertaken in Antarctica are subject to the requirements of both the Protocol and the US National Environmental Policy Act (NEPA). There are differences in the scope and intent of the Protocol and NEPA; however, both require environmental impact assessment (EIA) as part of the planning process for proposed actions that have the potential for environmental impacts. In this paper we describe the two instruments and highlight key similarities and differences with particular attention to EIA. Through this comparison of the EIA requirements of NEPA and the Protocol, we show how the requirements of each can be used in concert to provide enhanced environmental protection for the antarctic environment. NEPA applies only to actions of the US government; therefore, because NEPA includes certain desirable attributes that have been refined and clarified through numerous court cases, and because the Protocol is just entering implementation internationally, some recommendations are made for strengthening the procedural requirements of the Protocol for activities undertaken by all Parties in Antarctica. The Protocol gives clear and strong guidance for protection of specific, valued antarctic environmental resources including intrinsic wilderness and aesthetic values, and the value of Antarctica as an area for scientific research. That guidance requires a higher standard of environmental protection for Antarctica than is required in other parts of the world. This paper shows that taken together NEPA and the Protocol call for closer examination of proposed actions and a more rigorous consideration of environmental impacts than either would alone. Three areas are identified where the EIA provisions of the Protocol could be strengthened to improve its effectiveness. First, the thresholds defined by the Protocol need to be clarified. Specifically, the meanings of the terms “minor” and “transitory” are not clear in the context of the Protocol. The use of “or” in the phrase “minor or transitory” further confuses the meaning. Second, cumulative impact assessment is called for by the Protocol but is not defined. A clear definition could reduce the chance that cumulative impacts would be given inadequate consideration. Finally, the public has limited opportunities to comment on or influence the preparation of initial or comprehensive environmental evaluations. Experience has shown that public input to environmental documents has a considerable influence on agency decision making and the quality of EIA that agencies perform.  相似文献   
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Microcystins are cyanobacterial hepatotoxins capable of accumulation into animal tissues. The toxins act by inhibiting specific protein phosphatases and both non-covalent and covalent interactions occur. The 2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) method determines the total, i.e. the sum of free and protein-bound microcystin in tissues. The aim of the method development in this paper was to tackle the problems with the MMPB methodology: the rather laborious workflow and the loss of material during different steps of the method. In the optimised workflow the oxidation recovery was of acceptable level (29-40%), the extraction efficiency good (62-97%), but the signal suppression effect from the matrix remained severe in our system (16-37% signal left). The extraction efficiency for the determination of the free, extractable microcystins, was found to be good, 52-100%, depending on the sample and the toxin variant and concentration.  相似文献   
35.
Quantifying polychlorinated biphenyl (PCB) residues in nestlings of avian species is a common method for assessing trophic transfer and risk at PCB-contaminated sites. The proportion of nestling PCB mass due to maternal transfer is often accounted for by subtracting total PCB mass in eggs from nestlings. However, variation in physicochemical properties and metabolism among congeners may lead to differences between egg contribution based on total PCBs and dioxin-like congeners. We examined congener-specific variation in contribution of PCBs from eggs to nestlings in tree swallows and European starlings. Egg contribution of total PCB mass was 14.3 and 16.2%, respectively, whereas contribution based on dioxin-like congeners was 14.8 and 13.6%, respectively. These data suggest that using total PCB mass in eggs to adjust estimates of PCB accumulation in nestlings may not reflect patterns for dioxin-like congeners, potentially over or under-estimating the risk of toxicity of PCBs.  相似文献   
36.
Although interest in regulatory focus research continues to grow, there has been very little work to date on the assessment and usefulness of regulatory focus in the workplace. The present research effort reports the results of a series of studies designed to assess the validity and utility of the Regulatory Focus at Work Scale (RWS). The results indicate that the RWS is reliable, valid, and showed incremental validity beyond general and trait‐like measures of regulatory focus in predicting relevant work outcomes of task performance, citizenship performance, safety performance, and productivity performance. The overall results of these studies support our claims that the RWS shows utility in predicting workplace outcomes and should prove useful for future research on regulatory focus in the workplace. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
37.
Two biological nutrient removal modes, consisting of anaerobic, anoxic, and oxic sequences, were tested in a full-scale sequencing batch reactor. The modes, identified as BNR-S1 and BNR-S2, had average total nitrogen removals of 84 and 89%, respectively, for the months of August to October. Over the same period, total phosphorus removals for BNR-S1 and BNR-S2 were 88 and 87%, respectively. In contrast, total nitrogen and total phosphorus removals for the regular aerobic mode were 54.7 and 44.7%, respectively. When the wastewater temperature changed from approximately 20 to 15 degrees C in the winter months, total nitrogen and total phosphorus removals for BNR-S2 were reduced to 81 and 70%, respectively. Total nitrogen effluent concentrations were between 2.5 and 4 mg-N/L (at approximately 20 degrees C), while the effluent total phosphorus concentrations were between 1 and 2 mg/L. The BNR-S2 mode was found to require less energy per kilogram of soluble chemical oxygen demand removed than the regular and BNR-S1 modes.  相似文献   
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The conceptual underpinnings for adaptive management are simple; there will always be inherent uncertainty and unpredictability in the dynamics and behavior of complex ecological systems as a result non-linear interactions among components and emergence, yet management decisions must still be made. The strength of adaptive management is in the recognition and confrontation of such uncertainty. Rather than ignore uncertainty, or use it to preclude management actions, adaptive management can foster resilience and flexibility to cope with an uncertain future, and develop safe to fail management approaches that acknowledge inevitable changes and surprises. Since its initial introduction, adaptive management has been hailed as a solution to endless trial and error approaches to complex natural resource management challenges. However, its implementation has failed more often than not. It does not produce easy answers, and it is appropriate in only a subset of natural resource management problems. Clearly adaptive management has great potential when applied appropriately. Just as clearly adaptive management has seemingly failed to live up to its high expectations. Why? We outline nine pathologies and challenges that can lead to failure in adaptive management programs. We focus on general sources of failures in adaptive management, so that others can avoid these pitfalls in the future. Adaptive management can be a powerful and beneficial tool when applied correctly to appropriate management problems; the challenge is to keep the concept of adaptive management from being hijacked for inappropriate use.  相似文献   
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