Horizontal transfer of parasitic sex ratio distorters between crustacean hosts

Parasitic sex ratio distorters were artificially transferred within and between crustacean host species in order to study the effects of parasitism on host fitness and sex determination and to investigate parasite–host specificity. Implantation of Nosema sp. to uninfected strains of its Gammarus duebeni host resulted in an active parasite infection in the gonad of recipient females and subsequent transovarial parasite transmission. The young of artificially infected females were feminized by the parasite, demonstrating that Nosema sp. is a cause of sex ratio distortion in its host. In contrast, we were unable to cross-infect Armadillidium vulgare with the feminizing microsporidian from G. duebeni or to cross-infect G. duebeni with the feminizing bacterium Wolbachia sp. from A. vulgare

International Organizations as Corporate Actors: Agency and Emergence in Theories of International Relations

In this paper, the implicit and explicit conceptualizations of international organizations found in the three major theories of international relations are outlined and compared. It turns out that in a neorealist framework, international organizations can be explained; however, they exhibit no autonomy and cannot therefore be conceptualized as a corporate actor. Principally, the same applies to rational choice institutionalism, although limited autonomy is conceivable. Both theories are reductionist in the sense that they do not allow a corporate actor beyond the nation-state. International organizations are at best instruments of state interests. Solely social constructivist theories allow a conceptualization of international organizations as partly autonomous corporate actors. The reason for this conceptual openness lies in its ontology that includes ideational factors such as knowledge and ideas. The concept of emergence gives the core explanation for international organization autonomy: identities and interests of states and international organizations constitute each other mutually. This is specified by referring to the generation of new knowledge within international organizations as the key feature which accounts for feedbacks to the member-states of international organizations. This power of international organizations to alter perceptions and identities of their own ‘founding fathers’ makes them more than state instruments. International organizations thereby gain autonomy, which justifies conceiving of them as high-order corporate actors in international relations.

The Role of Choice in Social Dilemma Experiments

On the basis of problems related to asymmetric information, self-governance has been proposed and often empirically found to be superior to the external imposition of rules in social dilemma situations. The present paper suggests and experimentally analyses a different line of argument, namely to what extent behavioral aspects can explain these findings. We study this hypothesis using the simplest, most general dilemma form: the prisoner's dilemma (PD). We compare behavior when players are given the possibility of choosing between two different representations of the same PD, to behavior when players are externally assigned to play a specific game. We find that cooperation rates are significantly higher in the games that were chosen.Freedom of Choice, Self-governance, Social Dilemmas, Framing

The Role of Choice in Social Dilemma Experiments

On the basis of problems related to asymmetric information, self-governance has been proposed and often empirically found to be superior to the external imposition of rules in social dilemma situations. The present paper suggests and experimentally analyses a different line of argument, namely to what extent behavioral aspects can explain these findings. We study this hypothesis using the simplest, most general dilemma form: the prisoner’s dilemma (PD). We compare behavior when players are given the possibility of choosing between two different representations of the same PD, to behavior when players are externally assigned to play a specific game. We find that cooperation rates are significantly higher in the games that were chosen.Freedom of Choice, Self-governance, Social Dilemmas, Framing

The Role of Rivalry. Public Goods versus Common-Pool Resources

Despite a large theoretical and empirical literature on public goods and common-pool resources, a systematic comparison of these two types of social dilemmas is lacking. In fact, there is considerable confusion about these two types of dilemma situations. As a result, they are often treated alike. In this paper we argue that the degree of rivalry is the fundamental difference between the two games. We show that rivalry implies that both games cannot be represented by the same game theoretic structure. Fur-thermore, we experimentally study behavior in a quadratic public good and a quadratic common-pool resource game with identical Pareto opti-mum but divergent interior Nash equilibria. The results show that partici-pants clearly perceive the differences in rivalry. Aggregate behavior in both games starts relatively close to Pareto efficiency and converges to the respective Nash equilibrium.

Home enteral nutrition in eating disorders

Weight restoration is crucial for successful treatment of anorexia nervosa (AN). Without it, patients may face serious or even fatal complications of severe starvation. Renutrition should take into account clinical characteristics unique to these patients, such as gastroparesis and fear of gaining body weight. The efficacy of tube feeding and home-tube feeding (Home-TF) has been suggested in AN and proven in bulimia nervosa (BN). TF and home-TF allow a better body weight gain (mainly fat-free mass) in AN patients and a strong decrease in the frequency and the intensity of binge-eating/purging episodes at relatively short-term (1 year) in BN patients. In AN, home-TF does not increase anxiety, depression, or worsen the eating behavior. In BN patients, home-TF decreases anxiety and depressive state and improves the quality of life. The goal of home-TF is not to cure the patients, but only to avoid serious malnutrition and its complications and to insure a better investment of the patients for their psychotherapy. Home-TF must be associated with psychotherapy, namely cognitive behavioural therapy and family therapy in adolescents. If the fear of gaining body weight is too high, the risk of failure of home-TF, because of poor compliance, is increasing. In any case, the aims and the goals of home-TF should be extensively explained. (C) 2013 Published by Elsevier Masson SAS. RESUME La nutrition entérale à domicile (NEAD) a fait en partie la preuve de son efficacité en cas d’anorexie mentale. La NEAD est très efficace à court terme contre les crises de boulimie. La NEAD permet une plus grande prise de poids et de masse maigre dans l’anorexie que l’approche classique. La NEAD permet aussi une diminution importante de la fréquence et de l’intensité des crises de boulimie. Elle n’altère pas l’humeur, ni n’aggrave le comportement alimentaire. La NEAD n’a pas pour objectif de guérir les malades, mais de passer un cap et de rendre la psychothérapie plus pertinente. La NEAD ne doit pas remplacer le travail diététique, ni faire faire l’économie du travail cognitif et comportemental. Si le malade a trop peur de grossir, la NEAD a de grandes chances d’être rejetée ou mise en échec. Il est donc essentiel de bien cibler les malades et de bien leur expliquer la démarche thérapeutique

Fusion terminée, fusion interminable ? Le cas Peugeot-Citroën

Quand, lors d'une fusion entre des firmes dont la valeur provient de marques fortes, les dirigeants décident de maintenir ces marques, il est probable qu'ils enclenchent un processus de nature indéterminable ou, tout du moins, un processus dont la fin est indéterminable. C'est ce que semble montrer le cas de la fusion entre Peugeot et Citroën, étudié sur une période de plus de trente ans