Pipage Rounding: A New Method of Constructing Algorithms with Proven Performance Guarantee

The paper presents a general method of designing constant-factor approximation algorithms for some discrete optimization problems with assignment-type constraints. The core of the method is a simple deterministic procedure of rounding of linear relaxations (referred to as pipage rounding). With the help of the method we design approximation algorithms with better performance guarantees for some well-known problems including MAXIMUM COVERAGE, MAX CUT with given sizes of parts and some of their generalizations.     

Investigating Possible Effects of Ethnicity and Age on Gambling as an Escape

Previous research has shown that there are a number of risk factors for disordered and problem gambling, including an individual’s ethnicity and age. Endorsing gambling as an escape has also been shown to contribute to and maintain disordered gambling. The present study examined potential interactions between ethnicity and age as they relate to disordered gambling, as well as if ethnicity and age would be predictors of endorsing gambling as an escape. Three hundred fifteen adults from the United States completed measures relating to gambling. Participants were grouped into ethnic categories of Caucasian and non-Caucasian, and age groups of 18–25, 26–35, 36–55, and 56 years old and above. Non-Caucasians reported more gambling problems than Caucasians. A significant interaction was found between ethnicity and age for 36–55 year olds. Overall, participants were more likely to gamble for positive than negative reinforcement. However, only gambling as an escape was a significant predictor of disordered gambling. Implications and limitations are discussed with the thought that these results are informative to practitioners treating disordered gambling.     

Combined Effects: The Influence of Organizational Form and Structural Characteristics on Contract Performance in Mixed Sector Markets

Social service contracting to nongovernmental organizations is popular form of privatization across the world. Although nonprofits are preferable social service providers for legal and normative reasons, governments in the United States increasingly rely on for-profit organizations to deliver social services. This trend warrants further exploration about whether nonprofits or for-profits perform according to theoretical expectations when they exist in the same market. This study employs qualitative comparative analysis (QCA) to examine how sector-public, nonprofit, and for-profit-combines with structural variables to produce acceptable contract performance in juvenile justice programs. QCA is a discovery-oriented research tool that determines whether combinations of variables within cases produce a specific outcome and whether those combinations are consistent across cases. I find sector is not a necessary or sufficient predictor of acceptable performance on its own. Rather it combines with market factors to lead to acceptable contract performance. Combinations vary by sector, indicating that sectors behave differently in similar circumstances. The primary theoretical contribution of this paper is to provide a nuanced account of contract performance in mixed sector markets.     

Comparison as a Universal Learning Action

This article explores ‘comparison’ as a universal metasubject learning action, a key curricular element envisaged by the Russian Federal State Educational Standards. Representing the modern learner’s fundamental pragmatic skill embedding such core capacities as information processing, critical thinking, robust decision-making, and effective problem solving, the universal learning action of ‘comparison’ has become a new professional challenge for educators, in terms of both understanding the underlying theoretical framework and ensuring that appropriate instructional models are deployed. The author seeks to clarify either of these aspects by providing a plain discussion of how the basic mechanisms of comparison as a cognitive device can be incorporated into clear and simple classroom aids and algorithms supporting goal-directed learning.     

Transient detailed balance and product form for reaction networks

This paper explores the boundary of the set of reaction networks that have an exact transient (truncated) multidimensional Poisson or product-form distribution for the number of particles of different types. Motivated by the birth–death process, we introduce the notions of transient detailed balance and delay functions, and use these notions to obtain the novel transient product-form distribution in a coagulation-fragmentation process for polymers with a tree-like structure from that of the pure coagulation process.     

The impact of child support on child health

The broad goals of child support policy are to keep children in single-parent families out of poverty and to make sure that their material needs are met. One potentially important, but relatively understudied, set of measures of child well-being are health outcomes. A fixed-effects analysis of data from the Child and Young Adult file of the 1979 National Longitudinal Survey of Youth shows that, conditional upon receipt of some amount of child support, higher payment levels are associated with significantly greater odds of having private health insurance coverage and significantly lower odds of poor or declining health status. These effects persist even after controlling for other factors that are likely to be correlated with child support payments, including total family income and paternal visitation patterns.