On minimum <Emphasis Type="Italic">m</Emphasis>-connected <Emphasis Type="Italic">k</Emphasis>-dominating set problem in unit disc graphs

Minimum m-connected k-dominating set problem is as follows: Given a graph G=(V,E) and two natural numbers m and k, find a subset S⊆V of minimal size such that every vertex in V∖S is adjacent to at least k vertices in S and the induced graph of S is m-connected. In this paper we study this problem with unit disc graphs and small m, which is motivated by the design of fault-tolerant virtual backbone for wireless sensor networks. We propose two approximation algorithms with constant performance ratios for m≤2. We also discuss how to design approximation algorithms for the problem with arbitrarily large m. This work was supported in part by the Research Grants Council of Hong Kong under Grant No. CityU 1165/04E, the National Natural Science Foundation of China under Grant No. 70221001, 10531070 and 10771209.     

Maternal Age,Psychological Maturity,Parenting Cognitions,and Mother–Infant Interaction

In the context of the trend toward delayed childbearing, the aim of this study was to examine relations among maternal age and the quality of maternal interactive behavior at 7 months assessed using sensitivity and mind‐mindedness, while also considering whether age effects were attributable to psychological maturity and parenting cognitions. Participants were 150 Australian mothers (mean age 33‐years) and their firstborn infants who were participating in a prospective study of parenthood. Path analysis showed maternal age had both direct and indirect associations with maternal interactive behavior. Older mothers made more mind‐related comments to their infants. They were also more sensitive; however, this effect was indirect and explained by greater psychological maturity (hardiness) and a more internal locus of control with regard to parenting. Results suggest that older maternal age may confer some benefits in terms of responsive parenting in infancy.     

Proactive Parenting and Children's Effortful Control: Mediating Role of Language and Indirect Intervention Effects

We examined associations of proactive parenting, child verbal ability, and child effortful control within the context of a randomized prevention trial focused on enhancing parenting practices in low‐income families. Participants (N = 731) were assessed annually from the age of two to five, with half randomly assigned to the Family Check‐Up (FCU). Results indicated that the child's verbal ability at the age of three partially mediated the influence of proactive parenting at the age of two on children's effortful control at the age of five. More importantly, the FCU indirectly facilitated children's effortful control by sequentially improving proactive parenting and children's verbal ability. The findings are discussed with respect to taking a more integrative approach to understanding early predictors and the promotion of self‐regulation in early childhood.     

Pathways to Independent Living in Early Adulthood: Marriage,Semiautonomy, and Premarital Residential Independence

Data from the National Longitudinal Study of the High School Class of 1972 are used to examine factors influencing young adults' departure from the parental home and the initial pathways taken, including leaving home for marriage, residential semi-autonomy (Semi), and premarital residential independence (PRI). Parents' education and continuing in school decrease the likelihood of leaving home via marriage and increase the likelihood of leaving home via Semi or PRI. All other factors considered affect all pathways out of the parental home in the same direction, but in differing magnitudes. The predominant influences on PRI are indicators of modern family values, whereas the predominant influences on leaving home for marriage are measures of resources, both those of the parents and those of the young adults.     

Ethnicity,religiosity and leaving home: The structural and cultural bases of traditional family values

In this paper we explore the links between ethnicity and religiosity and the transition to adulthood by examining variation in expectations to live independently from parents before marriage. We focus both on the structure of social networks and on the values transmitted within them to discover how they are linked to family life. Our findings show that variation in premarital residential independence is linked in part to the use of a foreign language and foreignness. Residential concentration and ecological and religious institutional contexts are important factors as are the values associated with religious denomination and religiosity. These findings suggest the continuing importance of ethnicity and religiosity as critical elements shaping family norms.     

Leadership and followership.

Along with the well-known leadership traits, there are some subtle characteristics of true leaders. Managing managers, making decisions, tolerating diversity, and showing a sense of humor are other marks of leadership that physician executives should possess.     

Women,work, and transformations in agricultural production*

Dans cet article l'auteur clarifie la différence entre deux élements clés qui ont marqué le développement de la production agricole au Québec et au Canada au cours des quatre dernières décennies, à savoir la modernisation de l'agriculture et son insertion dans le modèle capitaliste. Elle examine comment chacun de ces facteurs respectifs affecte la participation des femmes à l'agriculture. Les données proviennent d'une petite paroisse du Québec: il s'agit d'entrevues semi-dirigées, realisées auprès des membres adultes de 63 families agricoles choisies au hasard. L'analyse indique que ni le développement de l'agriculture capitaliste, ni l'adoption de techniques modernes n'ont un effet independant (net) sur la participation des femmes. L'effet d'interaction entre ces deux facteurs est ce qui produit la plus forte variation quant au type et à la charge du travail que les femmes consacrent à l'agriculture. In this article, the author differentiates between two key elements in the development of agricultural production in Québec and Canada in the last four decades (the modernization of agriculture and the penetration of capitalist relations of production) and then tests the relative strength of each for producing change in women's participation level. Data were collected during a year of field work in a small Québec parish and consist of semi-structured interviews with the adult members of 63 randomly selected farm families. The findings indicate that neither the development of capitalist agriculture nor the adoption of modern methods have an independent effect on women's contribution. It is the interaction effect between the two that produces the greatest variation in the type and amount of work women devote to farming.     

Adolescent Problem Behavior in China and the United States: A Cross‐National Study of Psychosocial Protective Factors

An explanatory model of adolescent problem behavior (problem drinking, cigarette smoking, and general delinquency) based on protective and risk factors in the individual and in 4 social contexts (family, peer group, school, and neighborhood) is employed in school‐based samples from the People's Republic of China (N=1,739) and the United States (N=1,596). Despite lower prevalence of the problem behaviors in the Chinese sample, especially for girls, a substantial account of problem behavior is provided by the same protective and risk factors in both countries and for both genders. Protection is generally higher in the Chinese sample than in the U.S. sample, but in both samples protection also moderates the impact of risk. Despite mean differences in psychosocial protective and risk factors, as well as in problem behavior, in the 2 samples—differences that may reflect societal variation—the explanatory model has, to a large extent, cross‐national generality.