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1.
Spatial variation in soil inorganic nitrogen across an arid urban ecosystem   总被引:4,自引:1,他引:3  
We explored variations in inorganic soil nitrogen (N) concentrations across metropolitan Phoenix, Arizona, and the surrounding desert using a probability-based synoptic survey. Data were examined using spatial statistics on the entire region, as well as for the desert and urban sites separately. Concentrations of both NO3-N and NH4-N were markedly higher and more heterogeneous amongst urban compared to desert soils. Regional variation in soil NO3-N concentration was best explained by latitude, land use history, population density, along with percent cover of impervious surfaces and lawn, whereas soil NH4-N concentrations were related to only latitude and population density. Within the urban area, patterns in both soil NO3-N and NH4-N were best predicted by elevation, population density and type of irrigation in the surrounding neighborhood. Spatial autocorrelation of soil NO3-N concentrations explained 49% of variation among desert sites but was absent between urban sites. We suggest that inorganic soil N concentrations are controlled by a number of ‘local’ or ‘neighborhood’ human-related drivers in the city, rather than factors related to an urban-rural gradient.  相似文献   
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This study investigated factors affecting the adjustment of parentally bereaved children by reviewing existing literature and comparing it to observations made by professional social workers. Interviewees had between 1 1/2 and 22 years of experience in counseling bereaved children. The specific factors examined were age and sex of the bereaved child, circumstances of the death, and adjustment of remaining caregiver. Participants (n = 5) responded to an interview instrument specifically designed for this study which contained seven in-depth, open-ended questions. Participants’ replies were mostly in accordance with the literature, but also generated some new perspectives that had not been previously considered for this study and had not appeared in the literature. This study has implications for practice with parentally bereaved children and their surviving caregivers.Rebecca M. Hope, LCSW, Outpatient Clinician, New River Valley Community Services, 700 University City Boulevard, Blacksburg, VA 24060.Diane M. Hodge, Ph.D. is an Associate Professor of Social Work, Radford University, P.O. Box 6958, Radford, VA 24141; e-mail: dmhodge@radford.eduAddress correspondence to Rebecca M. Hope, LCSW, Outpatient Clinician, New River Valley Community Services, 700 University City Boulevard, Blacksburg, VA 24060; e-mail: rmhope@verizon.net  相似文献   
3.
Mobility analysis has traditionally concentrated on the task of charting flows in the two-way contingency table which relates occupational origin to occupational destination. It has not yet undertaken a unified analysis of intergenerational and intragenerational aspects of mobility. And only rarely does it incorporate terms which represent ordered concepts such as inequality or vertical movement. In contrast, path analysis has typically imposed strong orderings on the data, and it has been employed to tease out the relations among several occupational variables. Its main defect is that it entirely abstracts from shifts in mean occupational position, and also from change in the shape of the occupational distribution. Yet both of these are important sources of mobility. The present paper shows how two innovations in mobility analysis may be generalized to constitute a technique which unites the strengths of path analysis with those of log-linear analysis. The two innovations are (a) the conceptual disaggregation of perfect and exchange mobility, and (b) the imposition of an ordered component within each (K. Hope, 1981, Sociology 15, 19–55). The outcome of this generalization is a simple yet powerful account of mobility in Britain.  相似文献   
4.
Palliative care is specialized health care to improve quality of life for patients with serious illness and their families through prevention and relief of suffering. A Palliative Care Institute was held in western Washington to capture community voices about diverse needs, strengths, and opportunities for improvement of palliative care. Researchers employed qualitative methods to obtain thematic data, provide real-time analysis, and engage in a multivoting technique to reflect stakeholder interest in individual themes and prioritize larger group interests. Bronfenbrenner’s ecological systems framework was used to explore caregiver experiences. Within the microsystem, caregivers reported difficulties in interactions with medical providers as a key challenge. Within the mesosysytem, interactions between patients and medical providers and the impact on caregivers were explored. Within the exosystem, caregivers reported lack of control over the schedules of personal care staff. Macrosystem influences included impact of local culture on the development of palliative care services. Chronosystem influences include de-medicalization of childbirth and its impact on perceptions of palliative care. Implications include the need for social workers to be proactive in fostering trust and effective communication between care providers and caregivers, and the demand for health care provider training in communication with patients and families.  相似文献   
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In the Bayesian analysis of a multiple-recapture census, different diffuse prior distributions can lead to markedly different inferences about the population size N. Through consideration of the Fisher information matrix it is shown that the number of captures in each sample typically provides little information about N. This suggests that if there is no prior information about capture probabilities, then knowledge of just the sample sizes and not the number of recaptures should leave the distribution of Nunchanged. A prior model that has this property is identified and the posterior distribution is examined. In particular, asymptotic estimates of the posterior mean and variance are derived. Differences between Bayesian and classical point and interval estimators are illustrated through examples.  相似文献   
7.
This article summarizes a quantitative microbial risk assessment designed to characterize the public health impact of consumption of shell eggs and egg products contaminated with Salmonella Enteritidis (SE). This risk assessment's objectives were to: (1) establish the baseline risk of foodborne illness from SE, (2) identify and evaluate potential risk mitigation strategies, and (3) identify data gaps related to future research efforts. The risk assessment model has five modules. The Egg Production module estimates the number of eggs produced that are SE-contaminated. Shell Egg Processing, Egg Products Processing, and Preparation & Consumption modules estimate the increase or decrease in the numbers of SE organisms in eggs or egg products as they pass through storage, transportation, processing, and preparation. A Public Health Outcomes module then calculates the incidence of illnesses and four clinical outcomes, as well as the cases of reactive arthritis associated with SE infection following consumption. The baseline model estimates an average production of 2.3 million SE-contaminated shell eggs/year of the estimated 69 billion produced annually and predicts an average of 661,633, human illnesses per year from consumption of these eggs. The model estimates approximately 94% of these cases recover without medical care, 5% visit a physician, an additional 0.5% are hospitalized, and 0.05% result in death. The contribution of SE from commercially pasteurized egg products was estimated to be negligible. Five mitigation scenarios were selected for comparison of their individual and combined effects on the number of human illnesses. Results suggest that mitigation in only one segment of the farm-to-table continuum will be less effective than several applied in different segments. Key data gaps and areas for future research include the epidemiology of SE on farms, the bacteriology of SE in eggs, human behavior in food handling and preparation, and human responses to SE exposure.  相似文献   
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Incentive‐based approaches have gained policy interest in linking change in agricultural land management with environmental conservation. This article investigates how scheme design influences smallholder farmers' decisions to switch to organic farming to reduce water pollution, drawing on a study at a Ramsar wetland site providing water for the city of Bhopal. Results from a choice experiment suggest that transitional payments are necessary to overcome farmer constraints to adopt organic farming, and that effective land certification has the potential to act as a self‐enforcing mechanism linking farmer incomes with wetland conservation benefits.  相似文献   
10.
In November 2001, the Monterey Institute of International Studies convened a workshop on bioterrorism threat assessment and risk management. Risk assessment practitioners from various disciplines, but without specialized knowledge of terrorism, were brought together with security and intelligence threat analysts to stimulate an exchange that could be useful to both communities. This article, prepared by a subset of the participants, comments on the workshop's findings and their implications and makes three recommendations, two short term (use of threat assessment methodologies and vulnerability analysis) and one long term (application of quantitative risk assessment and modeling), regarding the practical application of risk assessment methods to bioterrorism issues.  相似文献   
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