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51.
The German cockroach is the most common pest of urban, low-income housing in the United States and is associated with high pesticide use by residents. Cockroach allergen is implicated in asthma exacerbation and initiation and in the growing social and medical aspects of the disease. A safe and secure home environment is an environmental justice issue, and environmentally sound and effective models of cockroach control are needed in public and low-income multifamily housing. One model that offers potential is the integrated pest management (IPM) peer educator model (IPM Educator) in public housing as a component of IPM. A pre-post-analysis of an IPM Educator pilot programme in Boston public housing was undertaken. Thirty-four moderate- to high-infested units received baseline assessment and three applications of gel baits and IPM treatment by a pest control operator. Before the first pest control application, residents received written notice to prepare their units for treatment, a standard procedure. Before the second and third pest control treatments, an IPM Educator instructed residents in basic pest biology and habits, preparation for treatment, and the role of sanitation in pest control. Results showed a significant improvement in rate of preparation for pest control treatment after the IPM Educator intervention when compared with the preparation rate before the education intervention, and a significant reduction in cockroach populations by the third visit in units that were prepared and had improved sanitation, when compared with unprepared units and unclean units. The IPM peer educator is a promising, low-cost model of educating and engaging residents of urban, low-income, multifamily housing in environmentally sound pest control, thereby giving them some power and control over their living environment. It is also a potential source of professional training and jobs for public housing and other low-income housing residents.  相似文献   
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Gouin T  Cousins I  Mackay D 《Chemosphere》2004,56(6):531-535
Given the paucity of experimental degradation half-life data for most organic chemicals, there is a compelling incentive to use available estimation software when undertaking assessments of chemical persistence and mass balance modeling studies. In this study, half-life data obtained from estimation software for a set of 233 organic chemicals in air, water, soil and sediments were shown to differ significantly from half-life data listed in handbooks. It is suggested that the widely available and used estimation software, EPIWIN (Estimations Program's Interface for Windows), overestimates the reactivity of persistent organic pollutants (POPs). Reasons for this overestimation are explored. It is concluded that the maximum "default half-life values" used by the EPIWIN software are too short for estimating half-lives of highly persistent chemicals such as PCBs. There is a need for estimation software such as EPIWIN to be more thoroughly calibrated against experimental derived half-life data for a wide range of chemicals, including potential POPs, thus improving their reliability.  相似文献   
55.
Gray whales are coastal migratory baleen whales that are benthic feeders. Most of their feeding takes place in the northern Pacific Ocean with opportunistic feeding taking place during their migrations and residence on the breeding grounds. The concentrations of organochlorines and trace elements were determined in tissues and stomach contents of juvenile gray whales that were taken on their Arctic feeding grounds in the western Bering Sea during a Russian subsistence harvest. These concentrations were compared to previously published data for contaminants in gray whales that stranded along the west coast of the US during their northbound migration. Feeding in coastal waters during their migrations may present a risk of exposure to toxic chemicals in some regions. The mean concentration (standard error of the mean, SEM) of sigmaPCBs [1400 (130) ng/g, lipid weight] in the blubber of juvenile subsistence whales was significantly lower than the mean level [27,000 (11,000) ng/g, lipid weight] reported previously in juvenile gray whales that stranded in waters off the west coast of the US. Aluminum in stomach contents of the subsistence whales was high compared to other marine mammal species, which is consistent with the ingestion of sediment during feeding. Furthermore, the concentrations of potentially toxic chemicals in tissues were relatively low when compared to the concentrations in tissues of other marine mammals feeding at higher trophic levels. These chemical contaminant data for the subsistence gray whales substantially increase the information available for presumably healthy animals.  相似文献   
56.
Both means and year-to-year variances of climate variables such as temperature and precipitation are predicted to change. However, the potential impact of changing climatic variability on the fate of populations has been largely unexamined. We analyzed multiyear demographic data for 36 plant and animal species with a broad range of life histories and types of environment to ask how sensitive their long-term stochastic population growth rates are likely to be to changes in the means and standard deviations of vital rates (survival, reproduction, growth) in response to changing climate. We quantified responsiveness using elasticities of the long-term population growth rate predicted by stochastic projection matrix models. Short-lived species (insects and annual plants and algae) are predicted to be more strongly (and negatively) affected by increasing vital rate variability relative to longer-lived species (perennial plants, birds, ungulates). Taxonomic affiliation has little power to explain sensitivity to increasing variability once longevity has been taken into account. Our results highlight the potential vulnerability of short-lived species to an increasingly variable climate, but also suggest that problems associated with short-lived undesirable species (agricultural pests, disease vectors, invasive weedy plants) may be exacerbated in regions where climate variability decreases.  相似文献   
57.
Fungal symbioses affect the diversity, dynamics, and spatial patterns of trees in tropical forests. Their ecological importance is partly driven by their inherent patchiness. We used epifoliar fungi, a guild of common, benign, obligate, fungal symbionts of plants, as a model system to evaluate the relative importance of host phylogeny, host relative abundance, and microclimate on the three-dimensional distribution of plant-fungus symbioses. In parallel studies in rainforests in Panama and Australia, most epifoliar fungi were able to colonize several plant lineages but showed significant host preferences within the local plant community. More closely related plant species were not more likely to share fungal symbionts. Instead, fungal species were more likely to be shared by more abundant hosts, which supported a greater number and diversity of fungi. Environmental conditions strongly affected spatial distributions, with sites in the dark understory 2.5- to fourfold more likely to have epifoliar fungi than in the exposed forest canopy. In the understory, fungal incidence increased with canopy openness. Canopy trees supported only a subset of the fungal symbionts found in the understory, suggesting that adult trees are not reservoirs of these fungal symbionts for understory juveniles.  相似文献   
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Stanfield, Les W. and Don A. Jackson, 2011. Understanding the Factors That Influence Headwater Stream Flows in Response to Storm Events. Journal of the American Water Resources Association (JAWRA) 1‐22. DOI: 10.1111/j.1752‐1688.2010.00518.x Abstract: Headwater drainage features (first‐ to second‐order streams) are the capillaries of the landscape that, among other things, moderate the timing and volumes of water available to the riparian and aquatic ecosystems. How these features respond to summer rainfall is poorly understood. We studied how geology and an index of land use/land cover influenced peak flows following rainfall events in 110 headwater stream sites that were studied over a four‐month period during a drought year. Highest peak flows were observed in the most urbanized catchments and in poorly drained soils, but specific responses were variable depending on both geology and land disturbance. Redundancy analysis indicated that both surficial geology and land disturbance were important factors influencing peak flows under drought conditions. We conclude that responses of these headwater streams to individual storms during drought conditions are unpredictable from data collected using our methods, but increased peak flows were associated with increased urban and agricultural development, but mitigated by surficial geology. These findings demonstrate the challenges to accurately predict flow conditions in headwater streams during periods of extreme weather that concurrently have the greatest potential effect on biota. The combination of these challenges and importance of such events indicates the need to develop new approaches to study and manage these resources.  相似文献   
60.
Abstract

The German cockroach is the most common pest of urban, low-income housing in the United States and is associated with high pesticide use by residents. Cockroach allergen is implicated in asthma exacerbation and initiation and in the growing social and medical aspects of the disease. A safe and secure home environment is an environmental justice issue, and environmentally sound and effective models of cockroach control are needed in public and low-income multifamily housing. One model that offers potential is the integrated pest management (IPM) peer educator model (IPM Educator) in public housing as a component of IPM. A pre–post-analysis of an IPM Educator pilot programme in Boston public housing was undertaken. Thirty-four moderate- to high-infested units received baseline assessment and three applications of gel baits and IPM treatment by a pest control operator. Before the first pest control application, residents received written notice to prepare their units for treatment, a standard procedure. Before the second and third pest control treatments, an IPM Educator instructed residents in basic pest biology and habits, preparation for treatment, and the role of sanitation in pest control. Results showed a significant improvement in rate of preparation for pest control treatment after the IPM Educator intervention when compared with the preparation rate before the education intervention, and a significant reduction in cockroach populations by the third visit in units that were prepared and had improved sanitation, when compared with unprepared units and unclean units. The IPM peer educator is a promising, low-cost model of educating and engaging residents of urban, low-income, multifamily housing in environmentally sound pest control, thereby giving them some power and control over their living environment. It is also a potential source of professional training and jobs for public housing and other low-income housing residents.  相似文献   
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