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41.
The skin is a route of exposure that needs to be considered when conducting a risk assessment. It is necessary to identify the potential for dermal penetration by a chemical as well as to determine the overall importance of the dermal route of exposure as compared with inhalation or oral routes of exposure. The physical state of the chemical, vapor or liquid, the concentration, neat or dilute, and the vehicle, lipid or aqueous, is also important. Dermal risk is related to the product of the amounts of penetration and toxicity. Toxicity involves local effects on the skin itself and the potential for systemic effects. Dermal penetration is described in large part by the permeability constant. When permeability constants are not known, partition coefficients can be used to estimate a chemical's potential to permeate the skin. With these concepts in mind, a tiered approach is proposed for dermal risk assessment. A key first step is the determination of a skin-to-air or skin-to-medium partition coefficient to estimate a potential for dermal absorption. Building a physiologically-based pharmacokinetic (PBPK) model is another step in the tiered approach and is useful prior to classical in vivo toxicity tests. A PBPK model can be used to determine a permeability constant for a chemical as well as to show the distribution of the chemical systemically. A detailed understanding of species differences in the structure and function of the skin and how they relate to differences in penetration rates is necessary in order to extrapolate animal data from PBPK models to the human. A study is in progress to examine anatomical differences for four species.  相似文献   
42.
The 1995 wave of the Add Health study is used to investigate the relative influence of parent gender and residence on patterns of parental involvement with adolescents. Adolescent reports (N =17,330) of shared activities, shared communication, and relationship quality with both biological parents are utilized. A multidimensional scaling analysis reveals that parent gender explains most of the variance in parent‐adolescent involvement, with residential status playing a secondary yet a fundamental role in accounting for these patterns. Resident mothers who do not live with adolescents’ biological fathers engage in the broadest range of activities with their children. Unpartnered resident fathers display patterns of parenting that are as similar to mothers as they are to other fathers.  相似文献   
43.
Are the decisions of American policymakers informed by generaltrends in the public’s ideology or by the public’spolicy-specific preferences? In this article we discuss twoexplanations for the types of public opinion information thatpoliticians collect and use. Using a unique data set of privatepolls from the White House of Richard Nixon, we find that whenopinion data on specific policies were available, the presidentrelied on them and not on general ideology data. On less importantissues, however, we find that the president often chose notto collect policy-specific data and instead relied on generalideology data. The differential collection and use of informationby policymakers reflect varying strategic calculations. Theyalso have profound implications for representative democracyand the demands placed on citizens and governors.  相似文献   
44.
45.
There are increasing calls for more child specific measures of poverty in developing countries and the need for such measures to be multi‐dimensional (that is not just based on income) has been recognised. Participatory Poverty Assessments (PPAs) are now common in international development research. Most PPAs have been undertaken with adults and there are still relatively few PPAs with children. The objective of the current study was to understand adults' and children's perceptions of the causes and consequences of child poverty in rural Vietnam using a variety of participatory methods. Poor children are perceived by poor children as those who lack basic needs such as food, clothes, and safe shelter. Poor children feel they do not receive enough attention from their parents, have to work and have no safe place to play.  相似文献   
46.
文章分析了循化话中语气词的使用特点,并对其形成的原因作了探讨。  相似文献   
47.
Summary.  The association of poor education and poor health has been consistently observed in many studies and in various countries. Thus far, studies examining the mechanisms underlying this association have looked at only a limited set of potential pathways. This study simultaneously examines six distinctive pathways, which have been hypothesized to link education and health and found support from previous studies. A causal analysis of education and health was performed using structural equation models. Data were used from six phases of the National Child Development Study, which is based on following up an initial sample of 17416 children who were born in 1958. The association between education and health appears to be explained by a combination of mechanisms: adolescent health and adult health behaviours for men and women, adult social class among men and parental social class among women. We conclude that improvements in population educational attainment may not automatically lead to improvements in population health, and that health policies for improving health and reducing health inequalities need to target specific causal pathways.  相似文献   
48.
Working with a treatment and observing team at the same time, behind the oneway mirror, offers a variety of ways to: (a) generate multiple realities; (b) work with two different models of family therapy simultaneously; and (c) provide feedback on the teams' own roles, rules and group process. The process that 6 trainees and two supervisors used with T and O teams to examine their own coevolution as a therapeutic system using the Milan model of family therapy and Ericksonian hypnotherapy is described. The article concludes with a discussion of the advantages and pitfalls of this type of dual supervision.  相似文献   
49.
Socioeconomic, medical care, and public health contexts are examined in Peruvian communities for their relationship to infant mortality. A deviant case analysis is used to uncover characteristics important in the social structure of Peruvian communities. Results from fieldwork in two "deviant" communities suggest that economic diversity, income disparity, social class fluidity, and women's autonomy, along with refined measures of medical care and public health resources, are important in understanding differentials in mortality. Attention is drawn to the community context and to the interplay of socioeconomic determinants affecting infant mortality.  相似文献   
50.
2 evaluative views of worker remittances draw opposite conclusions. The negative one posits that remittances increase dependency, contribute to economic and political stability and development distortion, and lead to economic decline that overshadows a temporary advantage for a fortunate few. The positive view sees remittances as an effective response to market forces, providing a transition to an otherwise unsustainable development. They improve income distribution and quality of life beyond what other available development resources could deliver. The implications are tested for labor supply countries to Europe and the Middle East. The implications of the negative are not supported. Although the dire predictions of the pessimistic view have not materialized, the converse - contributions of remittances to economic performance - should not be overstated due to a lack of data.  相似文献   
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