Min-cost multiflows in node-capacitated undirected networks

We consider an undirected graph G=(VG,EG) with a set T?VG of terminals, and with nonnegative integer capacities c(v) and costs a(v) of nodes v??VG. A path in G is a T-path if its ends are distinct terminals. By a multiflow we mean a function F assigning to each T-path P a nonnegative rational weight F(P), and a multiflow is called feasible if the sum of weights of T-paths through each node v does not exceed c(v). The value of F is the sum of weights F(P), and the cost of F is the sum of F(P) times the cost of P w.r.t. a, over all T-paths P. Generalizing known results on edge-capacitated multiflows, we show that the problem of finding a minimum cost multiflow among the feasible multiflows of maximum possible value admits half-integer optimal primal and dual solutions. Moreover, we devise a strongly polynomial algorithm for finding such optimal solutions.     

Partizipative Modellierung. Beteiligungsexperimente in der sozial?kologischen Forschung

Results of contemporary sociological studies suggest an on-going revaluation of the idea of participation in different areas of society. We argue that in environmental issues public participation increasingly becomes experimental. This means that actors mainly from science initiate and organise participation. These new forms of participation evolve in addition to traditional calls for participation which sometimes take on the form of protest by ecologically moved citizens. For socio-ecological research, experiments in participation are useful to develop concrete and applicable solutions in the field of sustainable development. Based on empirical research we show that the hoped-for gains in rationality attached to lay people participation materialises if the citizens?? self-interest is touched, if problems immediately afflict their life-world, and if participants can contribute special knowledge.     

Why Have Children in the 21st Century? Biological Predisposition, Social Coercion, Rational Choice

This review examines arguments and evidence pertaining to the question: why have children in settings where the net economic costs of children are clearly substantial? Thereview is organized around three themes: biologicalpredispositions, environment (social coercion) and rationalchoice. Specifically, we explore the argument that evolution hasproduced sets of genes that predispose persons to childbearing bymaking sex and parenthood pleasurable. We review sociologicalarguments regarding the pronatalism/antinatalism of societalinstitutions. Finally, we discuss arguments that stress therationality of childbearing decisions by appealing to biologicalpredispositions and the economic and non-economic values ofchildren. The authors speculate that while a modern socialstructure and rationale supportive of childbearing could beconstructed, such changes are not inevitable and may be difficultin the face of competing interests. Moreover, future social andtechnological change could alter the context of childbearingsubstantially. This uncertainty complicates policyrecommendations.     

Examining South Africa's options

South Africa's Options: Strategies for Sharing Power by F. van Zyl Slabbert and David Welsh. South African edition, David Philip, Cape Town 1979. pp.x & 196.     

Sexual Dynamics in Mentoring Relationships – A Critical Review

This paper considers the nature of the interpersonal dynamic in mentoring relationships and the correlation between a close mentoring relationship and the possibility of that relationship becoming romantic or sexual. In considering this issue we have reviewed the literature that is pertinent to this context; this includes research on the workplace as a sexualized environment, the criteria considered to be desirable for an effective mentoring relationship and issues of gender and sexual orientation in the workplace. In highlighting these issues we suggest that organizations, mentees and mentors should be made aware of the potential risks before embarking on a mentoring relationship, and suggest this is an area that clearly needs more research.     

The Relevance of Objective and Subjective Social Position for Self-Rated Health: A Combined Approach for the Swedish Context

The study investigates the health effects of subjective class position stratified by objective social position. Four types of subjective class were analysed separately for individuals with manual or non-manual occupational background. The cross-sectional analysis is based on the Swedish Level-of-Living Survey from 2000 and includes 4,139 individuals. The dataset comprises information on perceived class affinity and occupational position that was combined to conduct logistic regression models on self-rated health. An inverse relationship between self-rated health and the eight combinations of objective and subjective social position was found. Lower socio-economic position was associated with poor health. The largest adverse health effects were found for lower subjective social position in combination with lower occupational position. When the covariates education, father’s occupational position and income were added to the model, adverse effects on health remained only for females. Subjective social position helps to explain health inequalities. Substantial gender differences were found. It can be assumed that subjective class position captures a wide range of perceived inequalities and therefore complements the measure of occupational position.     

Optimality of the quasi-score estimator in a mean–variance model with applications to measurement error models

We consider a regression of y$y$ on x$x$ given by a pair of mean and variance functions with a parameter vector θ$\theta$ to be estimated that also appears in the distribution of the regressor variable x$x$. The estimation of θ$\theta$ is based on an extended quasi-score (QS) function. We show that the QS estimator is optimal within a wide class of estimators based on linear-in-y$y$ unbiased estimating functions. Of special interest is the case where the distribution of x$x$ depends only on a subvector α$\alpha$ of θ$\theta$, which may be considered a nuisance parameter. In general, α$\alpha$ must be estimated simultaneously together with the rest of θ$\theta$, but there are cases where α$\alpha$ can be pre-estimated. A major application of this model is the classical measurement error model, where the corrected score (CS) estimator is an alternative to the QS estimator. We derive conditions under which the QS estimator is strictly more efficient than the CS estimator.