Controllability for chains of dynamical scatterers

In this paper, we consider a class of mechanical models which consists of a linear chain of identical chaotic cells, each of which has two small lateral holes and contains a rotating disk at its center. Particles are injected at characteristic temperatures and rates from stochastic heat baths located at both ends of the chain. Once in the system, the particles move freely within the cells and will experience elastic collisions with the outer boundary of the cells as well as with the disks. They do not interact with each other but can transfer energy from one to another through collisions with the disks. The state of the system is defined by the positions and velocities of the particles and by the angular positions and angular velocities of the disks. We show that each model in this class is controllable with respect to the baths, i.e. we prove that the action of the baths can drive the system from any state to any other state in a finite time. As a consequence, one obtains the existence of at most one regular invariant measure characterizing its states (out of equilibrium)

The Crisis: Policy Lessons and Policy Challenges

Bruegel Director Jean Pisani-Ferry, with Agnès Bénassy-Quéré (CEPII, University Paris-Ouest and Ecole Polytechnique, Paris), Benoît Coeuré (Ecole Polytechnique, Paris) and Pierre Jacquet (ENPC, Paris, and Agence Française de Développement) provide an in-depth analysis of the financial crisis. The authors review the main causes of the crisis, pointing to three different, non-mutually exclusive lines of explanation: wrong incentives in the financial sector, unsustainable macroeconomic outcomes, and misunderstood and mismanaged systemic complexity. They also discuss supervisory and regulatory reform going forward, including an examination of the issues of moral hazard, the separation of retail and investment banking, the desirable size of financial institutions, risk management, the role of central banks, and other issues. This working paper was previously published as CEPII (Centre d'études prospectives et d'informations internationales) working document 2009-28.

How dieting makes some fatter: from a perspective of human body composition autoregulation

Dieting makes you fat – the title of a book published in 1983 – embodies the notion that dieting to control body weight predisposes the individual to acquire even more body fat. While this notion is controversial, its debate underscores the large gap that exists in our understanding of basic physiological laws that govern the regulation of human body composition. A striking example is the key role attributed to adipokines as feedback signals between adipose tissue depletion and compensatory increases in food intake. Yet, the relative importance of fat depletion per se as a determinant of post-dieting hyperphagia is unknown. On the other hand, the question of whether the depletion of lean tissues can provide feedback signals on the hunger–appetite drive is rarely invoked, despite evidence that food intake during growth is dominated by the impetus for lean tissue deposition, amidst proposals for the existence of protein–static mechanisms for the regulation of growth and maintenance of lean body mass. In fact, a feedback loop between fat depletion and food intake cannot explain why human subjects recovering from starvation continue to overeat well after body fat has been restored to pre-starvation values, thereby contributing to ‘fat overshooting’. In addressing the plausibility and mechanistic basis by which dieting may predispose to increased fatness, this paper integrates the results derived from re-analysis of classic longitudinal studies of human starvation and refeeding. These suggest that feedback signals from both fat and lean tissues contribute to recovering body weight through effects on energy intake and thermogenesis, and that a faster rate of fat recovery relative to lean tissue recovery is a central outcome of body composition autoregulation that drives fat overshooting. A main implication of these findings is that the risk of becoming fatter in response to dieting is greater in lean than in obese individuals.</jats:p

How dieting makes some fatter: from a perspective of human body composition autoregulation

Dieting makes you fat - the title of a book published in 1983 - embodies the notion that dieting to control body weight predisposes the individual to acquire even more body fat. While this notion is controversial, its debate underscores the large gap that exists in our understanding of basic physiological laws that govern the regulation of human body composition. A striking example is the key role attributed to adipokines as feedback signals between adipose tissue depletion and compensatory increases in food intake. Yet, the relative importance of fat depletion per se as a determinant of post-dieting hyperphagia is unknown. On the other hand, the question of whether the depletion of lean tissues can provide feedback signals on the hunger-appetite drive is rarely invoked, despite evidence that food intake during growth is dominated by the impetus for lean tissue deposition, amidst proposals for the existence of protein-static mechanisms for the regulation of growth and maintenance of lean body mass. In fact, a feedback loop between fat depletion and food intake cannot explain why human subjects recovering from starvation continue to overeat well after body fat has been restored to pre-starvation values, thereby contributing to ‘fat overshooting'. In addressing the plausibility and mechanistic basis by which dieting may predispose to increased fatness, this paper integrates the results derived from re-analysis of classic longitudinal studies of human starvation and refeeding. These suggest that feedback signals from both fat and lean tissues contribute to recovering body weight through effects on energy intake and thermogenesis, and that a faster rate of fat recovery relative to lean tissue recovery is a central outcome of body composition autoregulation that drives fat overshooting. A main implication of these findings is that the risk of becoming fatter in response to dieting is greater in lean than in obese individual

Comparing taxonomic and morphological biodiversity of tintinnids (planktonic ciliates) of New Caledonia

International audienceTintinnid ciliates are planktonic grazers of nanoplankton. They have a lorica (or shell) into which the ciliate cell can withdraw. The lorica provides information on both the identity and the ecology of the organism because characteristics of the lorica distinguish species and the diameter of the oral opening is related to the size of prey ingested. We examined the relationship between biodiversity estimates based on classifying specimens as belonging to a species or a simple morphological group defined by lorica oral diameter (LOD) in a presumably species-rich area, a tropical lagoon. Two sites were sampled in the lagoon off Nouméa over an annual cycle. The tintinnid fauna was species-rich (76 species) and represented a relatively even distribution of LOD sizes compared to other sites both tropical and temperate. Median LOD varied with the fraction of the chlorophyll concentration > 10 µm. Total chlorophyll concentration was related to tintinnid concentration and in turn weakly correlated with numbers of species and LOD size-classes. Numbers of species were closely related to numbers of LOD size-classes as were H' of species and H' (Shannon index) of LOD size-classes. Thus, metrics of a morphological characteristic, related to the ecology of the organisms can be used to estimate species diversity

How dieting makes the lean fatter: from a perspective of body composition autoregulation through adipostats and proteinstats awaiting discovery

Whether dieting makes people fatter has been a subject of considerable controversy over the past 30 years. More recent analysis of several prospective studies suggest, however, that it is dieting to lose weight in people who are in the healthy normal range of body weight, rather than in those who are overweight or obese, that most strongly and consistently predict future weight gain. This paper analyses the ongoing arguments in the debate about whether repeated dieting to lose weight in normal-weight people represents unsuccessful attempts to counter genetic and familial predispositions to obesity, a psychosocial reaction to the fear of fatness or that dieting per se confers risks for fatness and hence a contributing factor to the obesity epidemic. In addressing the biological plausibility that dieting predisposes the lean (rather than the overweight or obese) to regaining more body fat than what had been lost (i.e. fat overshooting), it integrates the results derived from the re-analysis of body composition data on fat mass and fat-free mass (FFM) losses and recoveries from human studies of experimental energy restriction and refeeding. These suggest that feedback signals from the depletion of both fat mass (i.e. adipostats) and FFM (i.e. proteinstats) contribute to weight regain through the modulation of energy intake and adaptive thermogenesis, and that a faster rate of fat recovery relative to FFM recovery (i.e. preferential catch-up fat) is a central outcome of body composition autoregulation in lean individuals. Such a temporal desynchronization in the restoration of the body's fat vs. FFM results in a state of hyperphagia that persists beyond complete recovery of fat mass and interestingly until FFM is fully recovered. However, as this completion of FFM recovery is also accompanied by fat deposition, excess fat accumulates. In other words, fat overshooting is a prerequisite to allow complete recovery of FFM. This confers biological plausibility for post-dieting fat overshooting – which through repeated dieting and weight cycling would increase the risks for trajectories from leanness to fatness. Given the increasing prevalence of dieting in normal-weight female and male among young adults, adolescents and even children who perceive themselves as too fat (due to media, family and societal pressures), together with the high prevalence of dieting for optimizing performance among athletes in weight-sensitive sports, the notion that dieting and weight cycling may be predisposing a substantial proportion of the population to weight gain and obesity deserves greater scientific scrutiny

Médecine générale en milieu rural (freins à l'installation)

Introduction : L accès aux soins est inégal en France. Les zones rurales sont particulièrement touchées car elles cumulent les départs en retraite massifs des médecins et les réticences d installation des nouveaux diplômés. L objectif de cette étude est de définir les freins à l installation en milieu rural chez les futurs médecins. Matériel et méthodes : Cette étude qualitative a été menée par voie téléphonique auprès de médecins généralistes et d internes travaillant en France métropolitaine. Le recueil des données a été réalisé entre le 27 avril et le 15 août 2013 par entretiens semi-dirigés. Résultats : Dix-huit entretiens ont permis de dégager trois types de freins à l installation en milieu rural. Les premiers étaient liés à la ruralité : problème de la définition de la ruralité, isolement global et difficultés d emploi pour le conjoint. Venaient ensuite les freins liés à la pratique de la médecine en milieu rural : isolement professionnel, surcharge de travail et proximité de la population. Les derniers freins étaient liés à la formation : sélection initiale des étudiants et stage ambulatoire en milieu rural. Conclusion : Les freins à l installation en milieu rural sont nombreux et non résolus par les mesures incitatives actuelles. Cependant les internes semblent porter un intérêt certain à l exercice de la médecine en zone rurale. L enjeu est donc de considérer les attentes des jeunes médecins pour espérer les voir s installer en zone rurale. D autres études pourraient préciser les motivations à l installation en milieu rural et évaluer l impact réel des mesures incitatives.Introduction: Health care access is unequal on the French territory. Rural areas are particularly affected as they accumulate both high level of aging doctor population leaving for retirement and reluctances to settle there from new graduates. The objective of this study is to identify the obstacles to settlement in rural areas for future physicians. Materials and Methods: This qualitative study was conducted by telephone among general practitioners and residents working in France. Data collection was conducted between April 27 and August 15, 2013 by semi-structured interviews. Results: Eighteen interviews were conducted and three types of settlement brakes in rural areas emerged. The first was related to rurality itself: the problem of rurality definition, overall isolation and employment difficulties for the spouses. The second obstacle was related to medical practice in rural areas: professional isolation, heavy workload and proximity with the population. The last brake was related to student s training: initial selection of doctors-to-be and ambulatory care internship in rural areas. Conclusion: Obstacles to settlement in rural areas are numerous and not resolved by the current incentive measures. However residents seem to be interested in the practice of medicine in rural areas. The challenge is therefore to take young doctors expectations into consideration to hope to see them settling in rural areas. Further studies may clarify motivations for settlement in rural area and assess the real impact of incentives.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Analyse du vécu et des stratégies mises en place par les médecins généralistes et les pédiatres suite à l interdiction des antitussifs chez les enfants de moins de deux ans

Les antitussifs étaient souvent prescrits chez les nourrissons lors d affections respiratoires bénignes. Leur interdiction chez les enfants de moins de deux ans, en 2010, a entrainé un changement dans les habitudes de prescription des médecins. Les objectifs de cette étude sont d analyser le vécu par les médecins de cette interdiction et d étudier les stratégies et les mesures alternatives mises en place à la suite de celle-ci. Il a été mené une enquête qualitative par entretiens téléphoniques auprès de médecins généralistes et pédiatres libéraux métropolitains. L interdiction est suivie et acceptée mais des critiques existent. La diffusion des recommandations et l éducation des parents sont les moteurs de ce changement. Des stratégies ont été élaborées pour faire face à la pression des parents. Un report de prescription est constaté. Il existe des freins à la désobstruction rhinopharyngée (DRP). Des obstacles à l adaptation des médecins et à l acceptation des recommandations persistent. Rassurer, informer les parents et structurer la prise en charge sont à la base des stratégies employées par les médecins. L origine du report de prescription s explique, en partie, par la propension des médecins à prescrire. Les mesures non-médicamenteuses peuvent favoriser l acceptation de la non-prescription d antitussifs. Réaliser une démonstration de la DRP est à promouvoir auprès des médecins généralistes. L éducation des parents à un rôle primordial pour faire accepter la non-prescription des antitussifs. Des éléments de réflexion sur les obstacles à l adaptation des médecins, le rôle des thérapeutiques non-médicamenteuses et sur les moyens de promouvoir la DRP sont apportés.Cough syrups were often prescribed to infants with minor breathing illnesses. Their ban for children below two years old, in 2010, lead to a change in physicians prescription habits. The objectives of this study are to analyze how this ban was experienced by the physicians, and to study the strategies and alternate measures they implemented following this cough medicines ban. A qualitative study was conducted thanks to semi guided phone interviews with fourteen general practitioners and private paediatricians in France. The ban was accepted even though criticism remains. A diffusion of recommendations and the information of the parents are the drivers of this change. Strategies have been developed to cope with the parents pressure. Recommendations are enforced although prescription of non recommended medicines was observed. Nasopharyngeal deobstructive treatments are often preferred but obstacles remain. Obstacles to the acceptance of recommendations and the physicians adaptation remain. Strategies developed by physicians are based on reassuring and informing the parents as well as organizing nursing. Prescription replacement by other medicines can be explained by the physicians tendency to prescribe. Non-medicinal measures can favor the acceptance of the cough medicines non-prescription and a demonstration of nasopharyngeal deobstructive treatments should be promoted. This study emphasizes the essential role of the parents information in the acceptance of antitussive non-prescription. This work also opens up on the obstacles for the physicians adaptation, the role of non-medicinal therapies and on means to promote nasopharyngeal deobstructive treatments.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Selection for reduced muscle glycolytic potential in Large White pigs. II. Correlated responses in meat quality and muscle compositional traits

International audienc

Is a practice-based rural research network feasible in Europe?

Research in family medicine is a well-established entity nationally and internationally, covering all aspects of primary care including remote and isolated practices. However, due to limited capacity and resources in rural family medicine, its potential is not fully exploited yet. An idea to foster European rural primary care research by establishing a practice-based research network has been recently put forward by several members of the European Rural and Isolated Practitioners Association (EURIPA) and the European General Practice Research Network (EGPRN). Two workshops on why, and how to design a practice-based research network among rural family practices in Europe were conducted at two international meetings. This paper revisits the definition of practice-based research in family medicine, reflects on the current situation in Europe regarding the research in rural family practice, and discusses a rationale for practice-based research in rural family medicine. A SWOT analysis was used as the main tool to analyse the current situation in Europe regarding the research in rural family practice at both meetings. The key messages gained from these meetings may be employed by the Wonca Working Party on research, the International Federation of Primary Care Research Network and the EGPRN that seek to introduce a practice-based research approach. The cooperation and collaboration between EURIPA and EGPRN creates a fertile ground to discuss further the prospect of a European practice-based rural family medicine research network, and to draw on the joint experience