A Variable Selection Criterion in the Linear Programming Approaches to Discriminant Analysis*

There are numerous variable selection rules in classical discriminant analysis. These rules enable a researcher to distinguish significant variables from nonsignificant ones and thus provide a parsimonious classification model based solely on significant variables. Prominent among such rules are the forward and backward stepwise variable selection criteria employed in statistical software packages such as Statistical Package for the Social Sciences and BMDP Statistical Software. No such criterion currently exists for linear programming (LP) approaches to discriminant analysis. In this paper, a criterion is developed to distinguish significant from nonsignificant variables for use in LP models. This criterion is based on the “jackknife” methodology. Examples are presented to illustrate implementation of the proposed criterion.     

An autecological interpretation of the firm and its environment

Explaining the survival and failure of firms is an important issue for researchers and managers of firms in society. Ecological approaches to the study of firms have existed for over 100 years, and have been increasingly popular during the past 40 years, especially since the pioneering works of Hannan and Freeman on one hand, and Aldrich on the other. This paper, in keeping with recent developments elsewhere in mainstream ecology outlines and positions the theoretical and philosophical foundations of an alternative ecological approach, autecology, that has not yet been formulated for the study of firms. The autecological approach affords the individual firm more autonomy in creating its own future evolutionary trajectory. The idea of an ecological complex is developed to provide clear focus on what is central to the application of autecology to the study of firms. The paper also considers several emergent research opportunities that highlight the potential value of employing an autecological approach to the study of firms.     

A Preliminary Examination of Covitality as Integrated Well-Being in College Students

The emergence of positive psychology has generated increased interest about the correlates of positive psychological functioning. Researchers have identified and studied various positive psychological constructs (e.g., hope, optimism, self-efficacy, gratitude, and life satisfaction) and found them to covary and to be positively associated with optimal human functioning and negatively associated with mental illness. This study of 528 college students examined the co-occurrence of selected positive psychological traits and explored their relations with a proposed second-order latent construct called covitality and with psychological well-being. Structural equation modeling examined each first-order positive psychology construct related to the second-order concept of covitality. Findings supported the second-order latent factor model of covitality, which was also significantly related to indicators of psychological well-being. Implications for theory development related to understanding positive human resources and applications within the context of college student populations are discussed.     

Reconfiguring Social Work Education to Fight HIV–AIDS: A Model for Developmental Contexts

This article charts the response of social work educators in addressing HIV–AIDS. Based at the University of the West Indies in the Republic of Trinidad and Tobago, the faculty within the Social Work Unit developed a model of teaching, research and practice that was innovative and transcended cultural, geographical and professional boundaries. The model has contributed a lasting legacy of knowledge and culturally relevant practices to enhance the capacity and effectiveness of social workers working with people living with HIV–AIDS (PLWHIV). Inherent in the propositions that underpinned the model was a belief in the role of education in alleviating psychosocial and other impacts of social problems. This article describes this unique initiative and discusses its relevance to current social work practice and the implications for contemporary social work education. The authors argue that while social work draws on a common body of knowledge, an established set of professional skills and a universal code of values, these central tenets of the profession should not be regarded as concrete and fixed but must be figured and reconfigured as needed to address emerging contemporary problems and their specific sociocultural manifestations.     

Identification and classification of postpartum psychiatric disorders.

1. Postpartum depression has been used as a catchall phase for many postpartum emotional symptoms. Categorizing a number of diverse disorders under one title has resulted in an inability to identify who is most at risk for developing postpartum problems. 2. The postpartum period is a particularly vulnerable period for depression, despite the fact that it is perceived as a time of joy and emotional well-being. 3. By increasing awareness among all health care professionals who care for women during the period following childbirth, postpartum psychiatric disorders can be identified early and treated correctly. 4. Limiting postpartum psychiatric disorders to postpartum depression may result in limited or inappropriate treatment options.     

Parenting in Context: Impact of Neighborhood Poverty,Residential Stability,Public Services,Social Networks,and Danger on Parental Behaviors

This prospective longitudinal study examined the unique and combined effects of neighborhood characteristics on parental behaviors in the context of more distal and more proximal influences. With a sample of 368 mothers from high‐risk communities in 4 parts of the United States, this study examined relations between race (African American or European American), locality (urban or rural), neighborhood characteristics, family context, and child problem behaviors, and parental warmth, appropriate and consistent discipline, and harsh interactions. Analyses testing increasingly proximal influences on parenting revealed that initial race differences in warmth and consistent discipline disappeared when neighborhood influences were considered. Although generally culture and context did not moderate other relations found between neighborhood characteristics, family context, and child behaviors, the few interactions found highlight the complex influences on parenting.