Population monotonic path schemes for simple games

A path scheme for a game is composed of a path, i.e., a sequence of coalitions that is formed during the coalition formation process and a scheme, i.e., a payoff vector for each coalition in the path. A path scheme is called population monotonic if a player’s payoff does not decrease as the path coalition grows. In this study, we focus on Shapley path schemes of simple games in which for every path coalition the Shapley value of the associated subgame provides the allocation at hand. Obviously, each Shapley path scheme of a game is population monotonic if and only if the Shapley allocation scheme of the game is population monotonic in the sense of Sprumont (Games Econ Behav 2:378–394, 1990). We prove that a simple game allows for population monotonic Shapley path schemes if and only if the game is balanced. Moreover, the Shapley path scheme of a specific path is population monotonic if and only if the first winning coalition that is formed along the path contains every minimal winning coalition. We also show that each Shapley path scheme of a simple game is population monotonic if and only if the set of veto players of the game is a winning coalition. Extensions of these results to other efficient probabilistic values are discussed.     

Passion,Intimacy, and Commitment in Casual Sexual Relationships in a Canadian Sample of Emerging Adults

Research on casual sexual relationships (CSRs) among emerging adults is prevalent, yet our empirical and theoretical knowledge of relationship processes involved in these relationships is limited. The present study’s objective was to compare four CSR partner types (acquaintance, friend, non-dating partner, ex-romantic partner) on passion, intimacy, and commitment, the components of Sternberg’s triangular theory of love. A total of 441 Canadians aged 18–25 years who were not in a romantic relationship, and who reported having had more than one sexual contact with their last CSR partner, completed an online survey. Across all partner types, passion was highest, followed by intimacy and commitment. Levels of passion, intimacy, and commitment generally increased with partner familiarity. However, CSR partner type differences on the three components were partially explained by CSR components (i.e., frequency of sexual activity, frequency of social activity, whether partners saw each other with the main goal of having sex, sexual exclusivity agreement, and hopes about the relationship). Results are consistent with CSRs’ emphasis on sexuality, and, to a lesser extent, emotions. However, they challenge the mainstream and scientific conflation of CSRs with an absence of emotional bond, commitment, or love.     

Managing Corporate Knowledge Experiences with SODA and V·I·S·A

It is often said that success in today's competitive environment depends on the acquisition and application of sound, relevant knowledge. This paper introduces two management science approaches that have been used for the effective management of knowledge, towards the development of strategy, planning and decision making, in a wide range of organizational settings. Both approaches make use of computer technology to provide a flexible and interactive environment incorporating a visual representation of the problem. The paper briefly describes each approach, together with a case study illustrating its use in practice. A number of common themes relevant to the management of knowledge are identified and discussed. The themes highlight the benefits which arise through the use of computer technology alongside a number of issues relevant to the management of the group process.     

When Passion Leads to Problematic Outcomes: A Look at Gambling

Vallerand et al. (2003) have proposed that individuals can have two distinct types of passion toward an activity. Harmonious passion, an internal force leading one to choose to engage in the activity, is proposed to be associated with positive consequences. Obsessive passion, an internal pressure forcing one to engage in an activity, is posited to be associated with negative consequences. The present study sought to determine the role of the two types of passion in various cognitive and affective states associated with dependence and problems with gambling. Participants (n = 412) were recruited at the Montréal Casino and given a questionnaire measuring passion toward gambling, as well as consequences associated with dependence and problem gambling. Results showed that obsessive passion for gambling predicted poorer vitality and concentration in daily tasks, as well as increased rumination, anxiety, negative mood, guilt, and problem gambling. These relations were not found for harmonious passion for gambling. Results are discussed in light of the motivational approach to passion (Vallerand et al., 2003).     

Australia's Social Wage

Public Expenditure and Social Policy in Australia By R.B. SCOTTON & HELEN FERBER (eds.)
Poor Policies: Australian Income Security 1972–77 By PATRICIA TULLOCH.     

Accounting for unsafe sex: Interviews with men who have sex with men

Semi‐structured one‐on‐one interviews with 102 gay and bisexual men were conducted to examine the reasoning processes men use to exempt themselves from practicing safe sex. Qualitative analysis of the interviews revealed the following recurring themes: (a) Many men who were in couple relationships avoided condom use for reasons involving intimacy or trust, or because both partners were HIV‐negative; (b) unsafe sex sometimes occurred inadvertently or involuntarily; (c) negative moods and self‐images were associated with unsafe sex; (d) by “intuiting” that their partner was HIV‐negative, participants exempted themselves from the need for safe sex; and (e) when the boundary between safe and unsafe was unclear, participants used a combination of unofficial and official guidelines to determine what is safe.     

Multivariate forests with missing mixed outcomes

In this article, we propose a multivariate random forest method for multiple responses of mixed types with missing responses. Imputation is performed for each bootstrap sample used to build the individual trees that form the forest. The individual trees are built using a weighted splitting rule allowing downweighting of imputed observations. A simulation study shows the benefits of this approach over complete case analysis when missing responses are missing completely at random and missing at random (MAR). In particular, the gain in prediction accuracy of the proposed method is larger in the MAR case and also increases as the proportion of missing increases.     

Adolescent Electronic Media Use: Instead of Doing What?

Adolescents like to watch TV and listen to the radio, even on school days, but their day contains, like for all other people, only 24 hours. What do those who use electronic media frequently neglect? Data from 14- and 16-year-old adolescents from 12 European countries and from the USA (EURONET sample) were analyzed (N = 3,250). The correlations between time spent using electronic media (EM) and 15 other daily activities were all negative, which is not surprising given the fact that the sum of all activities is bound to be 24 hours. We, therefore, calculated correlations between electronic media use and the proportions of each other activity within the remaining time. A clear pattern emerged. The method allowed us to identify “mandatory” activities that always have high priority, such as sleeping and attending school, and “optional” activities that enter into competition with electronic media use, including engaging in sports, playing music, leisure reading, and being with friends without media use. As to the mandatory activities, the correlations between media-using time and the proportions of remaining time were positive; relative to the optional activities, the correlations between media-using time and the proportions of remaining time were negative. While one might expect school homework to be regarded as mandatory, the correlation patterns identified it as optional. As to the average electronic media-using times, there were marked differences not only between the individual participants, but also between the countries. While Bulgarian adolescents spent an average of 2.37 hours of a regular school day using electronic media, French adolescents averaged only 1.72 hours.