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171.
Daughters from low‐income families who did not receive Aid to Families with Dependent Children (AFDC) are compared to daughters from low‐income families who did receive assistance to better account for family income in the intergenerational association of AFDC. The research models the timing of a daughter's first birth and, for those who become mothers, the number of years a daughter receives any AFDC. Women whose families received AFDC during their childhood are more likely to receive AFDC as adults relative to those women whose families did not receive AFDC. Controlling for family income in a more careful and comprehensive way than past research explains part but not all of the effects of childhood AFDC receipt. Among daughters from chronically poor families, however, parental AFDC use is not associated with additional years of AFDC participation. Although the present research cannot confirm or deny a causal role for parental welfare use, the intergenerational transmission of financial resources does explain part of the intergenerational association of welfare use.  相似文献   
172.
The tutorial is concerned with two types of test for the general lack of fit of a linear regression model, as found in the Minitab software package, and which do not require replicated observations. They aim to identify non-specified curvature and interaction in predictors, by comparing fits over the predictor region divided into two parts. Minitab's regression subcommand XLOF which gives the tests is only briefly documented in the manual and, unlike virtually all other statistical procedures in the software, it is not standard and cannot be readily found in textbooks. The two types of test are described here; they concern the predictors one-at-a-time and the predictors all-at-once. An example of their use is given. A suite of macros is available which reproduces the results of the XLOF tests in much more detail than is given by the XLOF subcommand.  相似文献   
173.
Entering the developmental spiral through affect attunement reactivates and revitalizes the thrust to continue development when it has been fixated, distorted or derailed. Achieving affect attunement is a vital dimension of the healing process. Basch describes how affect stimulates and controls the ordering and pattern matching function of the brain, motivating behavior and relationships. These theories are examined in selected vignettes illustrating the manner in which we seek to free individuals from stalemate in relationships, destructive behavior or depressive states.  相似文献   
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175.
This paper presents an algorithm for the construction of optimal or near optimal change-over designs for arbitrary numbers of treatments, periods and units. Previous research on optimality has been either theoretical or has resulted in limited tabulations of small optimal designs. The algorithm consists of a number of steps:first find an optimal direct treatment effects design, ignoring residual effects, and then optimise this class of designs with respect to residual effects. Poor designs are avoided by judicious application of the (M, S)-optimality criterion, and modifications of it, to appropriate matrices. The performance of the algorithm is illustrated by examples.  相似文献   
176.
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   
177.
Although surveys are extensively used in sociology, there has been a relative neglect of the effect of task definition upon results obtained. The present article examines the effects of one such task variable, length and specificity of the cue, on response sets concerning the frequency and quantity of alcohol consumed. In one survey format, respondents were asked to report the average number of days drinking per month, and the average number of drinks consumed on each of these occasions. In the second format, questions concerning the monthly frequency of alcohol consumption and quantity consumed were decomposed by twelve drinking locations. The results indicate dramatic increases both in terms of frequency and quantity between the two questionnaire formats. Implications of these results are discussed within the framework of the methodological phenomena of telescoping and the social psychological tendency to under-report threatening behaviors.  相似文献   
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179.
While applying theclassical maximum likelihood method for a certain statistical inference problem, Smith and Weissman [5] have noted that there are conditions under which the likelihood function may be unbounded above or may not possess local maximizers. Ariyawansà and Templeton [1] have derived inference procedures for this problem using the theory of structural inference [2,3,4]. Based on numerical experience, and without proof, they state that the resulting likelihood functions possess unique, global maximizers, even in instances where the classical maximum likelihood method fails in the above sense. In this paper, we prove that under quite mild conditions, these likelihood functions that result from the application of the theory of structural inference are well-behaved, and possess unique, global maximizers. This research was supported in part by the Applied Mathematical Sciences subprogram of the U.S. Department of Energy under contract W-31-109-Eng-38 while the author was visiting the Mathematics and Computer Science Division of Argonne National Laboratory, Argonne, Illinois.  相似文献   
180.
The multiple self-referent model (Brown-Collins & Sussewell, 1986) provides a comprehensive framework for understanding the personal, social, and historical aspects of self-concept formation in African American women and has important implications for understanding the complexity of career development issues for Black women. Excerpts from recorded interviews and autobiographical writings of four well-known African American women provide examples of the basic components of this model. Suggested interventions for career counseling with Black female clients are discussed.  相似文献   
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