Sequence Independent Lifting in Mixed Integer Programming

We investigate lifting, i.e., the process of taking a valid inequality for a polyhedron and extending it to a valid inequality in a higher dimensional space. Lifting is usually applied sequentially, that is, variables in a set are lifted one after the other. This may be computationally unattractive since it involves the solution of an optimization problem to compute a lifting coefficient for each variable. To relieve this computational burden, we study sequence independent lifting, which only involves the solution of one optimization problem. We show that if a certain lifting function is superadditive, then the lifting coefficients are independent of the lifting sequence. We introduce the idea of valid superadditive lifting functions to obtain good aproximations to maximum lifting. We apply these results to strengthen Balas' lifting theorem for cover inequalities and to produce lifted flow cover inequalities for a single node flow problem.     

A praxis and Research Agenda for Multicultural Human Services Organizations

Human services organizations in the United States are currently faced with the problems of a diminishing and shifting resource base coupled with increasing demands for services. In addition, national demographic changes with increasing social diversity, and a rise in racial, ethnic, gender and other group-based tensions have posed special challenges for human service organizations. By tracing the history of social work approaches to working with ethnic minorities, this paper argues that responses to environmental flux have in fact been inadequate in addressing issues of social inequalities and injustices. We articulate a vision of socially just and diverse human services organizations that are both empowering and empowered. We call these Multicultural Human Services Organizations (MHSO). We spell out praxis and research agendas that continue the social justice-social diversity mission that is central to our vision.     

Compensatory Weight Control Behaviors of Women in Emerging Adulthood: Associations Between Childhood Abuse Experiences and Adult Relationship Avoidance

Abstract

Objective: To examine correlates of compensatory weight control behaviors among women in transition between adolescence and adulthood. Participants: The authors recruited a sample of undergraduate women (N = 759) at a large northwestern university during the 2009–2010 academic year. Methods: Logistic regression was used to assess relations among childhood abuse, psychosocial functioning, adult dating relationship factors, and women's endorsement of compensatory weight control behaviors. Results: The final model reliably distinguished between participants who endorsed versus denied use of compensatory behaviors (χ²[5, N = 747] = 36.37, p < .001), with global psychosocial functioning and relationship avoidance accounting for the most variance. Conclusions: These findings illustrate the importance of considering childhood abuse histories and adult relationships while assessing young women's compensatory weight control behaviors.     

Relational and Overt Aggression in Childhood and Adolescence: Clarifying Mean‐level Gender Differences and Associations with Peer Acceptance

Research on relational aggression has drawn attention to how girls may be likely to aggress, but the role of gender is not fully understood. There are opposing views regarding whether relational aggression is most common among girls. Current findings demonstrate that when gender differences in relational aggression are assessed with peer nominations, gender differences favoring girls are more likely: (1) in adolescence than childhood; and (2) when statistical overlap with overt aggression is controlled. Results also indicated that associations of relational aggression with peer acceptance depend on the aggressor's gender, the peer rater's gender, and whether overlap with overt aggression is controlled. Associations of relational aggression with lower acceptance became non‐significant when overt aggression was controlled, suggesting that relational aggression displayed in isolation may not damage acceptance. In fact, in mid‐adolescence, girls’ relational aggression predicted greater liking by boys. Reducing relational aggression among adolescent girls may be especially challenging if the behavior is linked with acceptance by boys.     

Recruiting fathers to parenting programs: Advice from dads and fatherhood program providers

The benefits of high-quality father–child relationships for fathers and children alike are well documented. While evidence suggests parenting programs can improve the quality of father–child relationships, few fathers participate in such programs. This qualitative study aims to fill the gap in knowledge on best practices for recruiting urban African American fathers, a group of fathers with unique parenting challenges, to parenting programs. Focus groups were conducted with 29 fathers to gain their perspectives on recruitment strategies. Semi-structured interviews were also conducted with a nationwide sample of 19 fatherhood program providers to learn about their most successful recruitment strategies. Recruitment strategies based on emergent themes from the focus groups and interviews are presented here. Themes included using word-of-mouth recruitment, increasing advertising, targeting advertising specifically to urban African American fathers, providing transportation and incentives, recruiting through the courts, collaborating with other community agencies, and offering parenting programming along with other programming valued by fathers such as employment assistance. Implications for developing strategies for recruiting urban African American fathers to parenting programs are discussed.     

Intergroup Competition and Attitudes Toward Immigrants and Immigration: An Instrumental Model of Group Conflict

High levels of worldwide migration paired with increasingly negative attitudes toward immigrants and immigration in host countries indicate that it is crucial to gain an understanding of the bases of these attitudes. This article discusses one determinant of negative attitudes toward immigrants and immigration: perceived competition for resources. We present our instrumental model of group conflict, which suggests that competition for resources, and attempts to remove this competition, are important determinants of intergroup attitudes and behavior. We then review relevant research on perceived competition and attitudes toward immigrants and immigration. We conclude by discussing the implications of this research for attempts to alleviate tension between immigrants and members of host populations, and for our more general model of group conflict.     

Are girls more than boys subjected to disrupted conditions of upbringing?

Basing findings on data from the longitudinal programme Individual Development and Adaptation (IDA; n = 1383) it was found to be twice as common for girls to have been subjected to problematic upbringing conditions as for boys (here defined by experiencing major changes with regard to the child's caregivers; i.e. not just one parental divorce). This characterized 7.4% of the girls and 3.5% of the boys, a highly significant difference. A simple count of the number of parental transitions a child had been subjected to during upbringing also showed a sex difference in the same direction. As expected, girls with such disrupted upbringing showed adjustment problems during the school years, especially with regard to hyperactivity-related behaviours and conduct problems. The corresponding group of boys showed less pronounced adjustment problems. The generalizability of the results are discussed and tentative explanations presented for the sex differences that were found.     

论大学教师的元认知能力

元认知是对认知的认知。其本质是人对认知活动的自我意识和自我控制,包括元认知知识、元认知体验和元认知控制。大学教师的元认知能力则是教师对主体(自己和学生)内在差异、个别差异以及主体认知水平和影响认知水平的因素差异的了解和监控能力。大学教师元认知水平的高低与学生的发展以及教学质量的好坏密切相关。因而需要通过对教师内在素质的训练和外在督导等措施,培养教师对教学内容的把握、对课堂教学的调控以及反思与批判、学习和迁移等能力。