Subset sum problems with digraph constraints

We introduce and study optimization problems which are related to the well-known Subset Sum problem. In each new problem, a node-weighted digraph is given and one has to select a subset of vertices whose total weight does not exceed a given budget. Some additional constraints called digraph constraints and maximality need to be satisfied. The digraph constraint imposes that a node must belong to the solution if at least one of its predecessors is in the solution. An alternative of this constraint says that a node must belong to the solution if all its predecessors are in the solution. The maximality constraint ensures that no superset of a feasible solution is also feasible. The combination of these constraints provides four problems. We study their complexity and present some approximation results according to the type of input digraph, such as directed acyclic graphs and oriented trees.     

Work Opportunities in a Non-Traditional Setting for Women Exiting Welfare: A Case Study

The purpose of this research is to explore key issues regarding the need to provide jobs for women who are making the transition from welfare to wage work. A traditionally male-dominated industry, the secondary wood products industry, in a ten-parish rural region in northern Louisiana is used as a case study. One goal of the project is to explore barriers to expanding job opportunities for women in this industry, which is located in an economically disadvantaged region of the state. In-depth personal interviews were conducted with employers and business owners in this industry, and focus group discussions were conducted among employees at selected sites. Potential barriers to employing women in this industry are discussed, and recommendations for reducing barriers are made.     

The Relationship Between Perceived Interparental Conflict and Malaysian Young Adults' Attitudes Toward Divorce

In the context of an upward trend in divorce rates in Malaysia, this article explores the relationship between Malaysian young adults' perceptions of interparental conflict and their own attitudes toward divorce. Two questionnaires were administered to 160 young adults between 18 and 30 years old: the Attitude Towards Divorce Scale and the Perceptions of Interparental Conflict?Intensity/Frequency Scale. A positive relationship was found between perceived intensity and frequency of interparent conflict and attitudes toward divorce in males and females, respectively; however, the associations were weak. Future investigations of divorce need to take into consideration both the cultural factors that are influential within a society and how they shape gender norms within that population to gain a greater understanding of this relationship. Such investigations will increase the understanding of non-Western culture's unique interaction between attitudes and divorce, thus potentially aiding future efforts to strengthen marriages and families.     

A Model for Implementing an Evidence-Based Practice in Student Fieldwork Placements: Barriers and Facilitators to the Use of “SBIRT”

ABSTRACT

This article reports on focus group data analysis that was used to understand initial, largely positive outcomes from a university-based initiative to disseminate and implement an evidence-based practice (EBP)—Screening, Brief Intervention, and Referral to Treatment for Substance Use (SBIRT)—into student fieldwork placements, which are usual care social work settings. Focus groups were conducted with three groups of stakeholders involved in the ongoing project: social work department faculty (n = 10), bachelor- and master-level social work students (n = 8), and social work fieldwork instructors (n = 6). Dimensional analysis of the focus group data yielded results indicating that dissemination and implementation of SBIRT was influenced by agency- and school-level factors and perceived fit between the EBP and individual professional identity, intrapersonal characteristics, and timing. The resulting model, developed through the focus group analysis, is offered and shows how these factors interacted and affected training, supervision, and use of the EBP. The model provides social work educational programs and agencies a working tool for diagnosing and proactively addressing barriers and breakdowns in the EBP implementation process. Future research that tests the model as a diagnostic tool and generates knowledge about its influence in developing competent evidence-based practitioners is indicated. Future focus groups in relation to this initiative are needed to better understand these barriers and facilitators in the EBP implementation process and their critical roles in the process of translating SBIRT into standard social work practice.     

Conceptualizing social-ecological drivers of change in urban forest patches

Urban Ecosystems - We introduce a conceptual model of the urban forest patch as a complex social-ecological system, incorporating cross-scale interactions. We developed this model through an...     

Household finance management and the labour market: a case study in Hartlepool

This paper reports on the results of a survey carried out in Hartlepool towards the end of 1989. It considers the problems posed by data collection through survey methods to enquire into the management of household finances, and adopts a procedure which first examines treatment of the man's wage, and follows with additional questions about use of the woman's wage, access to personal spending money, and the location of final authority over spending. The data are based on a comparsion between four different groupings with reference to the man's employment status: Group A: couples in which the man has been unemployed for at least the last 12 months. Group B: couples in which the man is currently employed and has held the same job for at least the last twelve months. Group C: couples in which the man has been recently recruited to employment. Group D: a residual group covering any other status, notably early retirement, sickness, disability or student status. An age range of 20–55 was imposed. Marked contrasts were found between these groupings though further variation was introduced by employment for the woman. Broadly speaking there are two instances of heightened financial influence for women: low income prompts female management, whilst women's employment (and therefore higher income) increases joint management. It is in the traditional and declining situation of a sole male earner in which female authority or influence is at its lowest.     

Robust optimization in distribution-based demand planning: a model for negotiation support

In this paper a model for negotiation support in tactical procurement planning is designed, which is based on a real planning problem from the liquid gas trade sector. The problem is modeled as an assignment problem and transformed into a robust form. Computational experiments using data from a practice partner are presented to demonstrate the effective decision support of our approach.     

How Watershed Immigration Policies Affect American Public Opinion Over a Lifetime

Important political events are known to influence political socialization and development (Green, Palmquist, and Schickler 2002 ). It is also possible that such events impact political socialization within particular age cohorts, and also across important social groups who may be impacted differently by landmark events. This paper examines whether landmark immigration events can leave a permanent mark on an individual's views toward immigrants and immigration, and whether that impact varies across different ethnic/racial groups in the United States Specifically, we examine the cohort of individuals who were in their formative years during the passage of major US immigration bills that were proposed or enacted from 1965 to 2010. Altogether, we focus on four pieces of landmark immigration legislation. The findings reveal variations on the effect of these events depending on the group in question; a relationship also emerges between these landmark legislative events and attitudes on immigration policies. The analysis contributes to an ongoing debate regarding the ways in which political elites influence attitudes, and we discuss how the findings may apply to other contexts outside the US.