Marital strategies for regulating exposure to HIV

In a setting where the transmission of HIV occurs primarily through heterosexual contact and where no cure or vaccine is available, behavioral change is imperative for containing the epidemic. Abstinence, faithfulness, and condom use most often receive attention in this regard. In contrast, this article treats marriage as a resource for HIV risk management via mechanisms of positive selection (partner choice) and negative selection (divorce of an adulterous spouse). Retrospective marriage histories and panel data provide the evidence for this study and results indicate that men and women in Malawi increasingly turned to union-based risk-avoidance strategies during the period that the threat of HIV/AIDS materialized. Although both sexes strategize in a similar fashion, men are better equipped than women to deploy these strategies to their advantage. The article concludes with reflections on the long-term and population-level implications of these coping mechanisms.     

On zero-sum $$\mathbb {Z}_{2j}^k$$-magic graphs

Let \(G = (V,E)\) be a finite graph and let \((\mathbb {A},+)\) be an abelian group with identity 0. Then G is \(\mathbb {A}\)-magic if and only if there exists a function \(\phi \) from E into \(\mathbb {A} - \{0\}\) such that for some \(c \in \mathbb {A}, \sum _{e \in E(v)} \phi (e) = c\) for every \(v \in V\), where E(v) is the set of edges incident to v. Additionally, G is zero-sum \(\mathbb {A}\)-magic if and only if \(\phi \) exists such that \(c = 0\). We consider zero-sum \(\mathbb {A}\)-magic labelings of graphs, with particular attention given to \(\mathbb {A} = \mathbb {Z}_{2j}^k\). For \(j \ge 1\), let \(\zeta _{2j}(G)\) be the smallest positive integer c such that G is zero-sum \(\mathbb {Z}_{2j}^c\)-magic if c exists; infinity otherwise. We establish upper bounds on \(\zeta _{2j}(G)\) when \(\zeta _{2j}(G)\) is finite, and show that \(\zeta _{2j}(G)\) is finite for all r-regular \(G, r \ge 2\). Appealing to classical results on the factors of cubic graphs, we prove that \(\zeta _4(G) \le 2\) for a cubic graph G, with equality if and only if G has no 1-factor. We discuss the problem of classifying cubic graphs according to the collection of finite abelian groups for which they are zero-sum group-magic.     

Voices of Children from Around the Globe; An International Analysis of Children's Issues at Child Helplines

Child helplines around the world are an important mental health resource for many children. In this study, an international database was analysed with a total of 25 million registered calls at a total of 111 helplines affiliated with Child Helpline International. The research was aimed at discovering if there are differences between the reasons for calling of children from different parts of the world, and if shifts in the studied 10‐year period can be observed. The data show that all child helplines are contacted by young people seek support with questions concerning abuse, sexual matters and school issues. The results from a mixed model also show significant differences in the reasons for calling between Africa, Asia, Europe, Latin America, North America, the Pacific region and the region Middle East and North Africa. Child helplines in Africa and other developing parts of the world received many calls related to safety and health (e.g. HIV/AIDS, commercial exploitation), whereas children and young people from Europe, North America and the Pacific more often discussed social and psychosocial issues with the helpline (e.g. mental health, peer and family relations). The reasons for calling were relatively stable for the studied period.     

Attitudes toward abortion among catholic Mexican-American women: The effects of religiosity and education

Contrary to observed trends in religious fertility and contraceptive use differentials, Catholic/non-Catholic differentials in attitudes toward abortion have not been converging. This study suggests that this may be due to an interaction between religiosity and education. In a sample of Catholic Mexican-American women in Los Angeles County, the authors found that among respondents brought up in Mexico, education had a liberalizing effect on their attitudes. With the exception of the most devout, the same trend was observed among U.S.-reared respondents. Among the most religious group, however, education had the opposite effect, suggesting that convergence will be delayed.     

A measure of aliasing and applications to two-level fractional factorials

This paper examines some properties of a measure of aliasing proposed by Hedayat, Raktoe, and Federer (1974). It is shown that in the case of balanced orthogonal designs with no repeated treatments, minimizing the alias measure is equivalent to minimizing tr Yar(ψ). Lower bounds are found for fixed eigenvalues of the design matrix. These results are applied to two-level fractional factorials to show that in certain cases classical fractional-factorial designs yield minimal solutions for the alias measure.     

Immigrants in a Restructuring Economy: A Partial Test of Theories

The article addresses the occupational integration of immigrants from the former USSR into the economy of the city of Tel Aviv. This process is examined from a structural perspective, which focuses on the location of immigrants as a group in the restructuring economy of Israel's main business centre.
Data from labour force surveys and income surveys conducted in 1992 and 1994 by Israel's Central Bureau of Statistics are used to analyse the distribution of veteran Israelis and recent immigrants among economic sectors and occupations.
Despite their superior academic and professional qualifications, immigrants were underrepresented in the business and financial services sector, the leading sector in post-industrial economies. They were most strongly represented in the personal services sector, where they replaced Palestinian workers. The findings lend support to both the restructuring and replacement hypotheses.     

The Impact of Manufacturers' Wholesale Prices on a Retailer's Shelf‐Space and Pricing Decisions*

This article examines shelf‐space allocation and pricing decisions in the marketing channel as the results of a static game played à la Stackelberg between two manufacturers of competing brands and one retailer. The competing manufacturers act as leaders that play a simultaneous and noncooperative game. They fix their transfer prices by taking into account the shelf‐space allocation and price‐markup decisions of their common exclusive dealer. The results indicate that the wholesale prices of brands are strongly linked to their share of the shelf. The main results of our numerical simulations may be summarized as follows: first, the lower the unit cost and/or the greater the price elasticity, the greater the shelf space allocated to that brand. Second, the higher the shelf‐space elasticity, the lower are the wholesale prices and the profits of all channel members.     

Managing terror. Public health officials learn lessons from bioterrorism attacks

When a photo-journalist presented with the first case of inhalation anthrax in the United States in 23 years, it marked the worse case of biological terrorism in our nation's history. It also marked a significant management challenge for numerous local, state and federal officials. Review what was learned and how we can better prepare for future attacks.