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331.
ABSTRACT

Residential care has increased in number of facilities and has grown in density in urban areas, yet it is disproportionately dispersed in cities and only beginning to meet the current long-term care need of older adults as an alternative to institutional and in-home care. California State Department of Social Services residential care facility data were linked with Los Angeles County census tract data to examine the spatial distribution of facilities through hot spot analysis of clusters of small and large facilities and zero-inflated negative binomial regression of census tract facility counts on older age and race groups, older disabled adults, and older adults in poverty in the area. The results show clusters of large facilities west of downtown Los Angeles and clusters of small facilities in the northern suburbs of the city in the San Fernando Valley. Increases in pre- and early-retired adults and older Hispanics in census tracts are associated with the greatest decreases in facility tract capacity in the area, whereas increases in the oldest old and older disabled adults are associated with the greatest increases. Understanding spatial disparities in residential care can help local agencies and developers plan and partner in more intentional and equitable development of facilities. The greatest opportunity for such development may lie in institutional tools for eldercare facility development such as the eldercare facility ordinance of Los Angeles and development of board and care facilities in residential zones of Los Angeles and other cities.  相似文献   
332.
Williams JL  Crone EE 《Ecology》2006,87(12):3200-3208
Negative impacts of invasive plants on natives have been well documented, but much less is known about whether invasive plants can cause population level declines. We used demographic models to investigate the effects of two invasive grasses on the demography and population growth of Anemone patens, a long-lived native perennial of North American grasslands. Demographic data of A. patens growing in patches characterized by Bromus inermis, Poa pratensis, or native grasses were used to parameterize integral projection models. Models based on both average conditions and those allowing for environmental stochasticity indicate that A. patens is slowly increasing in patches of native grass (lambda = 1.02) and declining in patches of invasive grasses, particularly those dominated by B. inermis (lambda = 0.93). Extinction probabilities indicate that A. patens should persist in native grass patches, but has a much higher probability of extinction in Bromus patches compared to Poa patches. While sensitivity analyses showed that survival had the biggest effect on population growth rates in all habitats, results of a Life Table Response Experiment (LTRE) revealed that slower individual growth rates in patches of invasive grasses contributed the most to the observed reduction in population growth. These results suggest that invasive grasses may cause slow declines in A. patens, despite short-term coexistence, and that controlling B. inermis only would not be sufficient to ensure A. patens persistence.  相似文献   
333.
The levels of polychlorinated dibenzo-dioxins (PCDDs), polychlorinated dibenzo-furans (PCDFs), coplanar polychlorinated biphenyls (coPCBs), and polybrominated diphenyl ethers (PBDEs) were measured in fish collected from San Francisco Bay in 2000 and from the California coast in 2001. The samples were composites of only the edible portions of the fish (skin on, skin off, or whole body minus head and guts) of comparable size and from distinct geographical areas. Sixty-five composite samples were analyzed for PCDD/PCDF/coPCBs, and 43 composite samples were analyzed for PBDEs. For all fish of all species from all sampling areas, the mean concentration of the sum of BDEs 47, 99, 100, 153, and 154 was 302 ng/g lipid weight, with BDE 47>100>99 approximately 154>153. For all fish of all species from all sampling areas, the mean PCDD/PCDF International Toxic Equivalent (I-TEQ) was 33.1 pg/g lipid. For the three coPCBs (77, 126, 169), the mean I-TEQ for all fish of all species from all sampling areas was 109 pg/g lipid. The highest concentrations of both PCDD/PCDF/coPCBs and PBDEs were found in the highly populated areas of San Francisco Bay, the Los Angeles area, and San Diego Bay.  相似文献   
334.
Riparian ecosystems, through their unique position in the agricultural landscape and ability to influence nutrient cycles, can potentially reduce NO3 loading to surface and ground waters. The purpose of this study was to determine the fate of NO3 in shallow groundwater moving along a lateral flowpath from a grass seed cropping system through an undisturbed mixed-species herbaceous riparian area. Soil A (30-45 cm) and C horizon (135-150 cm) NO3, dissolved oxygen, and nitrous oxide concentrations were significantly higher in the cropping system than the adjacent riparian area. Nitrate concentrations in both horizons of the riparian soil were consistently at or below 0.05 mg N L(-1) while cropping system concentrations ranged from 1 to 12 mg N L(-1). Chloride data suggested that NO3 dilution occurred from recharge by precipitation. However, a sharp decrease in NO3/Cl ratios as water moved into the riparian area indicated that additional dilution of NO3 concentrations was unlikely. Riparian area A horizon soil water had higher dissolved organic carbon than the cropping system and when the riparian soil became saturated, available electron acceptors (O2, NO3) were rapidly reduced. Dissolved inorganic carbon was significantly higher in the riparian area than the cropping system for both horizons indicating high biological activity. Carbon limitation in the cropping system may have led to microbial respiration using primarily O2 and to a lesser degree NO3. Within 6 m of the riparian/cropping system transition, NO3 was virtually undetectable.  相似文献   
335.
336.
Summary. Leaf disc choice and oviposition bioassays were used to examine the effects of larval experience with a Hoodia gordonii latex on subsequent behaviors. The latex deterred feeding and oviposition by “naïve” cabbage looper (Trichoplusia ni, Noctuidae) larvae and moths with no previous exposure to the material. “Experienced” insects, reared on a diet with the H. gordonii latex (1000 ppm), exhibited lesser feeding deterrence relative to naïve insects. Experienced female moths actually preferred to lay eggs on treated rather than control leaves. There was no observed transfer of behavioral preferences from experienced parents to their offspring. Our results suggest that moths may be acquiring oviposition preferences from larval feeding experience as described by Hopkins’ host selection principal (HHSP) or through chemical legacy.  相似文献   
337.
338.
Human noroviruses and hepatitis A virus (HAV) are commonly associated with outbreaks occurring in restaurant establishments and catered events. Food handlers are major contributing factors to foodborne illnesses initiated in the kitchen setting. In this study, transfer of HAV and murine norovirus (MNV-1), a human norovirus surrogate, between produce (cucumbers, strawberries, tomatoes, cantaloupes, carrots, and honeydew melons) and common kitchen utensils (graters and knives) was investigated. The extent of virus transfer to produce during utensil application, in the presence and the absence of food residue, and the impact of knife surface properties (sharp, dull, serrated) was also investigated. Transfer of MNV-1 and HAV from produce items, initially contaminated with ~5.5 log PFU, to knives and graters during application ranged from 0.9 to 5.1 log PFU. MNV-1 transfer to knives was the greatest for cucumbers, strawberries, and tomatoes, and the least for honeydew melons, while transfer of HAV to knives was greater for tomatoes and honeydew melons than strawberries, cantaloupes, and cucumbers. After preparation of a contaminated produce item, knife cross-contamination easily occurred as viruses were detected on almost all of the seven produce items successively prepared. Produce residues on utensils often resulted in less virus transfer when compared to utensils without residue accumulation. Knife surface properties did not impact virus transfer. The ease of virus transfer between produce and utensils demonstrated by the current study highlights the importance of efforts aimed toward preventing cross-contamination in the kitchen environment.  相似文献   
339.
Influenza A virus poses a major public health concern and is associated with annual epidemics and occasional pandemics. Influenza A H3N2 viruses, which are an important cause of human influenza, can infect birds and mammals. Contaminated undercooked poultry products including eggs with avian influenza virus constitute a possible risk of transmission to humans. In this study, a novel levulinic acid plus sodium dodecyl sulfate (SDS) sanitizer was evaluated for eggshell decontamination. Influenza A H3N2 virus-inoculated chicken eggshells were treated with a 5 % levulinic acid plus 2 % SDS, 2 % levulinic acid plus 1 % SDS, and 0.5 % levulinic acid plus 0.5 % SDS liquid solution for 1 min. Log reductions of viable viruses were observed by plaque assay. The 5 % levulinic acid plus 2 % SDS sanitizer provided the greatest level of influenza A H3N2 virus inactivation (2.23 log PFU), and differences in virus inactivation were observed for the various levulinic acid plus SDS concentrations tested (P ≤ 0.05). To the best of our knowledge, this is the first study demonstrating influenza A H3N2 virus inactivation on eggshells using a novel levulinic acid plus SDS sanitizer. The sanitizer may be useful for reducing egg contamination and preventing the spread of avian influenza virus to humans.  相似文献   
340.
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