Partitioning a weighted partial order

The problem of partitioning a partially ordered set into a minimum number of chains is a well-known problem. In this paper we study a generalization of this problem, where we not only assume that the chains have bounded size, but also that a weight w _i is given for each element i in the partial order such that w _i ≤w _j if i ≺ j. The problem is then to partition the partial order into a minimum-weight set of chains of bounded size, where the weight of a chain equals the weight of the heaviest element in the chain. We prove that this problem is -hard, and we propose and analyze lower bounds for this problem. Based on these lower bounds, we exhibit a 2-approximation algorithm, and show that it is tight. We report computational results for a number of real-world and randomly generated problem instances.     

Can we Lend?: Communicating Interlibrary Loan Rights

At the 22nd Annual North Carolina Serials Conference, focused on “Collaboration, Community, and Connection,” Linda Blake and Hilary Fredette of West Virginia University presented, ““Can we Lend?”: Communicating Interlibrary Loan Rights,” reviewing their experiences collaborating across an academic library to achieve the best possible interlibrary loan e-journal access within the bounds of sometimes inscrutable licenses.     

EBSCO Publishing

Abstract

EBSCO Publishing is an innovative company that has its roots in paper publishing. It now produces hundreds of online resources in a state-of-the-art facility located along the banks of the Ipswich River in Massachusetts. Considerable work occurs behind the scenes in Ipswich (and around the world) to produce the online databases in EBSCOhost that appear to the user at the click of a mouse. Jennifer Carroll toured the headquarters in Ipswich to learn about the processes that make these valuable resources available.     

Algorithmic construction of optimal block designs for two-colour cDNA microarray experiments using the linear mixed effects model

ABSTRACT

In this study, methods for efficient construction of A-, MV-, D- and E-optimal or near-optimal block designs for two-colour cDNA microarray experiments with array as the block effect are considered. Two algorithms, namely the array exchange and treatment exchange algorithms together with the complete enumeration technique are introduced. For large numbers of arrays or treatments or both, the complete enumeration method is highly computer intensive. The treatment exchange algorithm computes the optimal or near-optimal designs faster than the array exchange algorithm. The two methods however produce optimal or near-optimal designs with the same efficiency under the four optimality criteria.     

The Variable Sampling Interval (VSI) in an Analysis of Taguchi's On-line Quality Monitoring Procedure for Variables

The procedure of on-line process control for variables proposed by Taguchi consists of inspecting the mth item (a single item) of every m items produced and deciding, at each inspection, whether the mean value is increased or not. If the value of the monitored statistic is outside of the control limits, one decides the process is out-of-control and the production is stopped for adjustment; otherwise, it continues. In this article, a variable sampling interval (with a longer L and a shorter m ≤ L) chart with two set of limits is used. These limits are the warning (±W) and the control (±C), where W ≤ C. The process is stopped for adjustment when an observation falls outside of the control limits or a sequence of h observations falls between the warning limits and the control limits. The longer sample interval is used after an adjustment or when an observation falls inside the warning limits; otherwise, the short sampling interval is used. The properties of an ergodic Markov chain are used to evaluate the time (in units) that the process remains in-control and out-of-control, with the aim of building an economic–statistical model. The parameters (the sampling intervals m and L, the control limits W and C and the length of run h) are optimized by minimizing the cost function with constraints on the average run lengths (ARLs) and the conformity fraction. The performance of the current proposal is more economical than the decision taken based on a sequence of length h = 1, L = m, and W = C, which is the model employed in earlier studies. A numerical example illustrates the proposed procedure.     

Race and Place: Exploring the Intersection of Inequity and Volunteerism Among Older Black and White Adults

Although the historical impact of racial segregation and ongoing health and economic inequities between older Black and White adults is well documented, little is known about the relationships among race, individual- and neighborhood-resources, and formal volunteering in later life. This study explores this intersection. Individual-level data from 268 respondents aged 55+ were collected in the St. Louis metropolitan area through paper-based mail surveys. Objective neighborhood data were obtained at the zip code level from secondary sources and matched with respondents. Using exploratory factor analysis, we constructed a 14-item environmental scale with 3 neighborhood dimensions (economic, social, and built environment). Older Black adults had lower levels of education; had fewer financial assets; lived in neighborhoods with less economic resources and lower built environment scores; and fewer formally volunteered when compared to older White adults. Individual resources (financial assets, health) and neighborhood resources (social and built environment) were positively associated with formal volunteering among older Black adults. Only individual resources (age, marital status, financial assets, health) were associated with formal volunteering among older White adults. A coherent set of policies that bolsters individual and environmental capacities may increase the rate of volunteerism among older black adults.     

Internationally adopted children's general and adoption‐specific stressors,coping strategies and psychological adjustment

We examined stress, coping and psychological adjustment of 68 children, aged 8–12, who were internationally adopted to Spain. Using the Kidcope, all children were asked about the most stressful general and adoption‐related problem they experienced and the use and effectiveness of various coping strategies when dealing with the problem. For all reported problems, the nature of the problem (personal, interpersonal, regarding others), the content, the degree of stress it created and its perceived controllability were analysed. Emotional and behavioural functionings were assessed with the Behaviour Assessment System for Children. About half of the children mentioned specific problems concerning the adoption, with inracial adoptees reporting less adoption‐related problems than transracial adoptees. For general and adoption‐related problems, interpersonal problems were mentioned most often. With regard to the content, ‘relationships’ and ‘victimization’ were mentioned most often for general and adoption‐related problems, respectively. Adoption‐related problems were appraised as less controllable. No differences emerged in terms of coping with general or adoption‐related problems except for ‘self‐criticism’. Overall, the children used many coping strategies and were generally well‐adjusted. Identifying the problems and coping strategies of adoptees is important in order to help these children and their families tackle these stressors.     

Alternative moment approximations for berkson's minimum logit chi-squared estimator

Expressions are derived for the bias to order J^-1 , the variance to order J^-2 and the mean squared error to order J^-2 of Berkson's minimum logit chi-squared estimator where J is the number of distinct design points. These moment approximations are numerically compared to Monte Carlo estimates of the true moments and the moment approximations of Amemiya (1980) which are appropriate when the “average” number of observations per design point is large. They are used to compare the mean squared error of the minimum logit chi-squared estimator to that of the maximum likelihood estimator and to investigate the effect of bias on confidence intenrals constructed using the minimum logit chi-squared estimator.     

Hazards of stigma: the sexual and physical abuse of gay, lesbian, and bisexual adolescents in the United States and Canada

Some studies suggest lesbian, gay, and bisexual (LGB) teens are at higher risk than peers for violence at home, in school, and in the community. That can bring them into the child welfare system or services for runaway and homeless teens. This study compared self-reported experiences of sexual and physical abuse based on sexual orientation and gender in seven population-based surveys of youth. The authors used c2 and age-adjusted odds of abuse to compare bisexual to heterosexual, mostly heterosexual, and gay and lesbian students. They also provide case studies to illustrate the experiences of such youth.     

Nursing in tele-mental health

This article discusses a cooperative project involving an academic health sciences center, a state university, a women's shelter, and a community mental health center in East Texas, a medically underserved, rural region of Texas. The U.S. Department of Commerce provided grant funding to develop a telehealth network to provide an evaluation, referral, and treatment program for victims of domestic violence. Nurses were involved in all phases of the project, from initial conception through development, implementation, and evaluation. The authors concluded that all of the women involved in the study had significant mental health issues and other health concerns that were not being addressed by the existing health care delivery system. Without the use of telehealth, these women would have had limited access to primary health care and virtually no access to mental health services. The East Texas Tele-Mental Health Network demonstrates the value of the clinical and organizational skills that nurses bring to innovative models of mental health service delivery.