Social and semantic coevolution in knowledge networks

Socio-semantic networks involve agents creating and processing information: communities of scientists, software developers, wiki contributors and webloggers are, among others, examples of such knowledge networks. We aim at demonstrating that the dynamics of these communities can be adequately described as the coevolution of a social and a socio-semantic network. More precisely, we will first introduce a theoretical framework based on a social network and a socio-semantic network, i.e. an epistemic network featuring agents, concepts and links between agents and between agents and concepts. Adopting a relevant empirical protocol, we will then describe the joint dynamics of social and socio-semantic structures, at both macroscopic and microscopic scales, emphasizing the remarkable stability of these macroscopic properties in spite of a vivid local, agent-based network dynamics.     

Partner support during the prenatal testing period after assisted conception

Background

Pregnancy after infertility is a challenging experience. The first-trimester screening test may add stress. Partner support reduces psychological distress in pregnant women after spontaneous conception. No data are available for women who conceive via assisted reproductive technology.

Risk aversion in expected intertemporal discounted utilities bandit problems

We consider a situation where an individual is facing an uncertain situation, but may costly alter his knowledge of the uncertainties. We study in this context how risk aversion may modify the individual search behavior. We consider a one-armed bandit problem (where one arm is safe and the other is risky) and study how the agent risk aversion can change the sequence of arms selected. The main result is that when the utility function is more concave, the agent has more chances to select the safe arm. We also discuss how search is affected by risk aversion.     

Coparenting in Stepfamilies: A Cluster Analysis

The aim of this study was to identify types of coparenting in stepfamilies based on observational data and to examine whether these types differed regarding marital satisfaction and child adjustment. Forty-five couples attended two videotaped discussion tasks on topics of agreement and disagreement regarding coparenting issues. An exploratory cluster analysis identified three main types of coparenting in stepfamilies: (1) Cooperative coparenting (n = 19), (2) Complementing coparenting (n = 16), and (3) Conflictual coparenting (n = 10). The Complementing coparenting type appeared as a new type of coparenting that had not been described in earlier studies and that might be specific to coparenting between non-biological parents. Comparison between the three clusters showed no differences for marital satisfaction and child adjustment. Each cluster is illustrated by a family case to provide a better understanding of coparenting dynamics in stepfamilies.     

Always doing your best? Effort and performance in dynamic settings

Theory and Decision - Achieving an ambitious goal frequently requires succeeding in a sequence of intermediate tasks, some being critical for the final outcome, and others not. However, individuals...     

The Commission White Paper on a Strategy for a Future EU Chemicals Policy: The View of European Companies of American Parentage

After years of good service, EU legislation on chemicals is currently subject to a major review. This process, initiated by the Council of Ministers at Chester in April 1998, will soon lead to new legislative proposals. In the meantime, a review of the Commission's White Paper on "Strategy for a Future Chemicals Policy," published in February 2001, clearly shows that the regulatory landscape in this area will be significantly reshaped and that a new burden will be imposed on industry to demonstrate that the production and use of chemicals indeed conform to high standards of protection of human health and the environment. In the view of industry, on both sides of the Atlantic, while the objectives of the proposed reform can be supported, the measures proposed in the White Paper to implement these objectives are not properly balanced and will lead to substantial societal and economic drawbacks, unless significant adjustments are made. The purpose of this article is to present the pitfalls and difficulties of the reform as they are perceived by the EU Committee of the American Chamber of Commerce in Brussels, an organization that regroups about 150 European companies of American parentage, belonging to a broad range of European business sectors, including producers and users of chemicals. In view of the transatlantic and cross-business character of its membership, the EU Committee offers a different perspective on the debate.     

What Types of Training Improve Learners’ Performances in Second Language Listening Comprehension?

This study investigates the impact of a high-level and a low-level process-based L2 comprehension training on L1 French students’ listening performances. These students (N = 108) of English, Spanish, and German came from five different classes. After a L2 comprehension pretest, the participants were divided into two experimental groups. During the experimental phase, the two groups listened to the same three documents in their respective L2. The first group undertook listening comprehension activities relying on low-level processes, while the second group undertook activities aiming at fostering their use of high-level processes. These second types of activities were based on the Metacognitive Awareness Listening Questionnaire (MALQ) (Vandergrift, Goh, Mareschal & Tafaghodatari, 2006). As hypothesized, less skilled listeners trained to automatize low-level processes, scored significantly higher on the comprehension posttest than on the pretest. However, the hypothesis that more skilled listeners trained to develop high-level listening processes, would score better on the posttest than on the pretest could not be verified. Nevertheless, we observed some tendencies showing that more skilled learners had drawn some benefits from the training. In our conclusion, we argue that the impact of a high-level and a low-level process-based L2 comprehension training strongly depends on learners’ initial levels.     

Put–call parity and generalized neo-additive pricing rules

We study price formulas suited for empirical research in financial markets in which put–call parity is satisfied. We find a connection between risk and the bid–ask spread. We further study the compatibility of the model with market frictions, and determine market subsets where the Fundamental Theorem of Asset Pricing applies. Finally, we characterize the price formula.

     

A Semi-Nonparametric Approach to Model Panel Count Data

In count data models, overdispersion of the dependent variable can be incorporated into the model if a heterogeneity term is added into the mean parameter of the Poisson distribution. We use a nonparametric estimation for the heterogeneity density based on a squared Kth-order polynomial expansion, that we generalize for panel data. A numerical illustration using an insurance dataset is discussed. Even if some statistical analyses showed no clear differences between these new models and the standard Poisson with gamma random effects, we show that the choice of the random effects distribution has a significant influence for interpreting our results.     

Mortality due to External Causes in Three Rural Areas of Senegal

Mortality due to external causes was measured over the period 1985–2004 in three rural areas of Senegal—Bandafassi, Niakhar and Mlomp – whose populations have been under continuous demographic surveillance for many years. The standardized annual rate of deaths due to external causes is 31 deaths per 100,000 inhabitants in Niakhar, 56 in Bandafassi and 102 in Mlomp. The causes of injury-related deaths generally reflect the rural living environment, with relatively few deaths due to road accidents (1.9 deaths per 100,000 inhabitants in Niakhar, 3.0 in Bandafassi and 2.0 in Mlomp), but many deaths due to falls (8.6 deaths per 100,000 inhabitants in Niakhar, 15.1 in Bandafassi and 23.3 in Mlomp). For certain causes, mortality varies considerably. Snake bites, for example, cause 0.1 deaths per 100,000 inhabitants in Niakhar, 13.4 in Bandafassi and 3.0 in Mlomp. The differences between sites are linked in this case to the relative concentrations of wildlife, in turn linked to differences in the local environment and in population densities (144 inhabitants per sq.km in Niakhar versus 19 in Bandafassi and 114 in Mlomp). Although the study areas are still largely unaffected by causes of death associated with development, such as traffic accidents, mortality due to external causes is high.