Online Social Networks and Trust

Social Indicators Research - We use Italian data from the Multipurpose Household Survey to explore how participation in social networking sites (SNS) such as Facebook and Twitter affects the most...     

Leadership in education: Effective U.K. college principals

College leaders face increasing challenges to manage complex responsibilities. They must possess a wide variety of managerial and leadership skills to be successful in academic environments, which are beginning to resemble more traditional organizational frameworks. The study examined in this article explored the relationships among managerial style, organizational climate, and several measures of college‐student performance with a sample of British further education college principals (similar to U.S. community college presidents). While considering the influence of various background factors, such as the size of the college, student funding, and years of experience, several significant relationships emerged demonstrating a significant association between principals' managerial behaviors and measures of college and student performance.     

Social-cognitive determinants of physical activity attendance in older adults

The present study evaluated whether, and to what extent, the constructs implicated in the theory of planned behavior could predict behavioral intention to exercise and exercise-class attendance of older adults (age 65-90 years) already enrolled in a physical activity program. The study also evaluated whether including self-efficacy judgments might improve the predictive capacity of the model. Participants (N = 1,095) were randomly sampled Italian volunteers from exercise classes for older adults. First, they completed questionnaires assessing the above-mentioned constructs. Then, class attendance was recorded during the following 3 months. Results indicated a substantial correspondence between the model and the data. Perceived behavioral control and self-efficacy were the strongest predictors of behavioral intention, whereas attitudes and subjective norms only partially contributed to its prediction. The inclusion of self-efficacy improved the predictive capacity of the overall model. Finally, results showed a weak relation between behavioral intention and attendance rate in physical activity sessions.     

Semi‐conditional cash transfers in the form of family allowances for children and adolescents in the informal economy in Argentina

In 2009, Argentina introduced a new transfer programme for children and adolescents younger than age 18 (Universal Child Allowance) that extended coverage under the contributory programme for family allowances to include families in the informal economy and families of unemployed persons. This article describes this innovative programme, compares it with similar programmes in Latin America and analyses its impact on coverage and its possible effects on the welfare of the population. The results indicate that the extension of access to this type of benefit has reduced considerably the coverage gap for the poor and indigent and supports efforts to consolidate the operations of different and poorly coordinated transfer programmes.     

The mathematics of sex and marriage,revisited

We analyze the problem of modeling marriages in a two‐sex model of population dynamics. We first deal with the problem of incomplete and inconsistent census data and then use a simulator to compare the performance of a variety of marriage functions in modeling births and couples during the ten‐year period between consecutive U.S. censuses. Unlike most empirical methods for comparing marriage functions based on goodness of fit, the differences in the projections of the various functions in our method are of the same magnitude (or even smaller) than the errors between the projected and real data. We observe that for the population of the United States, the harmonic mean function frequently found and used in the literature is a quite poor performer when compared with many other functions in the family we use.     

Piketty comes to South Africa

One of the most valuable features of Capital and Ideology is its concern to take history seriously and consider how the emergence of different political and economic regimes relate to discourses about fairness and justice across time. This paper pushes this agenda further by acknowledging that the experience of a few developed nations should not be taken as the template for the generalized study of inequality dynamics across time and space. In this paper, we interrogate Piketty's analysis and policy proposals against specificities that are central to understanding the production and reproduction of inequalities within South Africa. We reflect on the South African case, the structure of inequality and its changes since 1994. We review a battery of policy interventions that have been implemented to address inequality in the last 25 years. We emphasize that the long shadow cast by centuries of colonialism and various forms of apartheid strongly affirm Piketty's emphasis on understanding history. But this is both affirmation and critique given the foundational, imbedded impact that this specific legacy has had on post‐apartheid society and its policies. Piketty is aware that the levels of inequality in South Africa are so high that this is “unknown territory.” We map out some of this territory to reveal how these extreme initial wealth and racial inequities inform the reproduction of inequalities in all dimensions and undermine well intentioned policies. We claim that understanding extractive histories, imbedded wealth inequalities, and complex social and political institutions allows us to understand and confront some of the reasons why even in light of progressive policies, many of which are in line with the proposals from Piketty, government interventions have thus far failed to reduce inequality.     

Who Should Pay for Interdependent Risk? Policy Implications for Security Interdependence Among Airports

We study interdependent risks in security, and shed light on the economic and policy implications of increasing security interdependence in presence of reactive attackers. We investigate the impact of potential public policy arrangements on the security of a group of interdependent organizations, namely, airports. Focusing on security expenditures and costs to society, as assessed by a social planner, to individual airports and to attackers, we first develop a game-theoretic framework, and derive explicit Nash equilibrium and socially optimal solutions in the airports network. We then conduct numerical experiments mirroring real-world cyber scenarios, to assess how a change in interdependence impact the airports' security expenditures, the overall expected costs to society, and the fairness of security financing. Our study provides insights on the economic and policy implications for the United States, Europe, and Asia.     

Missing data and forecasting in multivariate time series: An application of the common components dynamic linear model

Summary The paper deals with missing data and forecasting problems in multivariate time series making use of the Common Components Dynamic Linear Model (DLMCC), presented in Quintana (1985), and West and Harrison (1989). Some results are presented and discussed: exploiting the correlation between series, estimated by the DLMCC, the paper shows as it is possible to update state vector posterior distributions for the unobserved series. This is realized on the base of the updating of the observed series state vectors, for which the usual Kalman filter equations can be applied. An application concerning some Italian private consumption series provides an example of the model capabilities.     

The evaluation of DNA evidence in pedigrees requiring population inference

Summary. The evaluation of nuclear DNA evidence for identification purposes is performed here taking account of the uncertainty about population parameters. Graphical models are used to detail the hypotheses being debated in a trial with the aim of obtaining a directed acyclic graph. Graphs also clarify the set of evidence that contributes to population inferences and they also describe the conditional independence structure of DNA evidence. Numerical illustrations are provided by re-examining three case-studies taken from the literature. Our calculations of the weight of evidence differ from those given by the authors of case-studies in that they reveal more conservative values.