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61.
Most real-world shapes and images are characterized by high variability- they are not rigid, like crystals, for example—but they are strongly structured. Therefore, a fundamental task in the understanding and analysis of such image ensembles is the construction of models that incorporate both variability and structure in a mathematically precise way. The global shape models introduced in Grenander's general pattern theory are intended to do this. In this paper, we describe the representation of two-dimensional mitochondria and membranes in electron microscope photographs, and three-dimensional amoebae in optical sectioning microscopy. There are three kinds of variability to all of these patterns, which these representations accommodate. The first is the variability in shape and viewing orientation. For this, the typical structure is represented via linear, circular and spherical templates, with the variability accomodated via the application of transformations applied to the templates. The transformations form groups: scale, rotation and translation. They are locally applied throughout the continuum and of high dimension. The second is the textural variability; the inside and outside of these basic shapes are subject to random variation, as well as sensor noise. For this, statistical sensor models and Markov random field texture models are used to connect the constituent structures of the shapes to the measured data. The third variability type is associated with the fact that each scene is made up of a variable number of shapes; this number is not assumed to be known a priori. Each scene has a variable number of parameters encoding the transformations of the templates appropriate for that scene. For this, a single posterior distribution is defined over the countable union of spaces representing models of varying numbers of shapes. Bayesian inference is performed via computation of the conditional expectation of the parametrically defined shapes under the posterior. These conditional mean estimates are generated using jump-diffusion processes. Results for membranes, mitochondria and amoebae are shown.  相似文献   
62.
This article compares in regression models the effects of occupational status of both fathers and mothers simultaneously upon the attainment of men and women in the Irish Republic. The sample matches male respondents from the 1973/1974 Irish Mobility Study with the labour active female sibling next closest in age. Since the analysis compares working siblings and each 'matched pair' shares the same family origin characteristics, the problems attendant upon using a sample originally of men only are partially avoided. The results advance beyond previous research since, rather than separate models by gender, models include parents and children of both genders, allowing direct rather than indirect evaluation of gender-based determinants of occupational attainment. Both fathers and mothers significantly affect children's attainment, in ways that vary by the child's gender. The results highlight the salience of mothers' attainment for their children and question the 'mainstream' model of equivalent mechanisms of occupational attainment for both genders. Models of social mobility that consider men and women as special instances of a general perspective provide the most fruitful approach for further development.  相似文献   
63.
UNDERSTANDING MAIL SURVEY RESPONSE BEHAVIOR A META-ANALYSIS   总被引:5,自引:0,他引:5  
A meta-analysis of prior studies of techniques designed to inducemail survey response rates was conducted. Research encompassing184 effects (study outcomes) in 115 studies (articles) for 17predictors of response rate was examined. The average effectsize across all manipulations was r=.065, indicating an averageincrease of about 6.5 percent in response rates for manipulations.Effect sizes for specific predictors and two potential moderatorsof effects were examined. Results indicated that repeated contactsin the form of preliminary notification and follow-ups, appeals,inclusion of a return envelope, postage, and monetary incentives,were effective in increasing survey response rates. Significanteffect sizes for the predictors ranged from an increase in responseof 2 percent to 31 percent. Implications of the results forthe conduct of mail surveys and future research on mail surveyresponse behavior are discussed.  相似文献   
64.
Gay affirmative practice has recently been introduced into the social work literature as a culturally sensitive model for working with gay, lesbian, and bisexual (GLB) adults, however, this model has rarely been applied to practice with GLB youth. In this article, the authors review the literature to present the main tenets of gay affirmative practice, outline the challenges that GLB youth face, and delineate the environmental and individual strengths that can be enhanced to promote well-being. The authors then apply the gay affirmative practice model to GLB youth, offering concrete information about the specific knowledge, attitudes, and skills that social workers should acquire to better serve the unique, yet diverse, needs of GLB youth.  相似文献   
65.
Immigration is contributing to the U.S. population becoming increasingly ethnically diverse. This article examines the role of family relations and well-being among different generations of Black Caribbean immigrants. Family disruptions, such as migration, can have complex effects on the support networks and emotional well-being of family members. Data from a recently completed national study of American Blacks in the United States, however, reveal significant similarities across ancestry and immigrant status in family contact, solidarity and well-being. It is concluded that intrafamilial relations may serve to overcome barriers of geographical distance in providing comparable levels of contact, solidarity, and well-being for both U.S.-born and immigrant Black Caribbean family members of different generations. Because of the increasing numbers of immigrant elders, these sources of family support will become increasingly more important in bridging the gaps between government resources and needed assistance in an aging society.  相似文献   
66.
In this study, individualism vs collectivism, in line with the work of Triandis in 1985, was assessed in two groups of male and female students, in Egypt and Germany. The results confirm the effect that cultural background has on individualist vs collectivist orientations in both of these cultures for male and female students. Men and women scored higher on individualism in Germany than in Egypt, whereas collectivism scores were higher in Egypt than in Germany. These findings are discussed in terms of general recommendations for intercultural interventions that discourage viewing people solely in terms of group membership, and instead as distinct individuals.  相似文献   
67.
We employed 4,095 couples from both waves of the National Survey of Families and Households (NSFH) to test a model of couple violence drawn from several theoretical perspectives. The outcome distinguishes among nonviolent couples and those experiencing either physical aggression or intense male violence. According to the model, background characteristics of couples are related to relationship stressors, which affect the risk of violence via their tendency to promote verbal conflict. Considerable support for the model was found. Couples were at higher risk for one or both forms of violence if they were younger at union inception, had been together for less time, were both in their first union, had only one partner who was employed, had a nontraditional woman paired with a traditional man, had at least one partner who abused substances, had more children, had more frequent disagreements, exhibited a more hostile disagreement style, or lived in an economically disadvantaged neighborhood. Moreover, the effects of stressors such as the number of children and couples' employment status disparities appear to be mediated by disagreement frequency and disagreement style.  相似文献   
68.
Recent social changes have made husbands' emotional investments and wives' perceptions of equity in the division of housework crucial for women's marital happiness. But wives are also happiest in their marriages when they share a strong normative commitment to lifelong marriage with their husbands and when their husbands take the lead in breadwinning. Thus our research suggests that elements of the new and the old promote marital happiness among contemporary wives.  相似文献   
69.
The Personal Responsibility and Work Opportunity Act of 1996 created a paradigm shift in the financing, organization, and delivery of welfare programs in the United States. The act shifted revenue and authority to states, giving them great discretion to determine the specifics of their programs. First‐order devolution, combined with time limits and work requirements, set in motion a chain of events that moved Temporary Assistance to Needy Families (TANF) recipients into the labor force and off state welfare rolls. Second‐order devolution shifted revenue and authority to community‐based organizations (CBOs) to help former recipients remain employed, advance to higher paying jobs, and move their families toward economic self‐sufficiency. Early findings from project innovations in Texas and other states raise doubts about the capacity of these organizations to achieve these goals. State funders will need to provide ongoing technical assistance and support to “scale up” the capacity of CBOs to plan, implement, and manage local innovations in welfare reform.  相似文献   
70.
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