Physicians self selection of a payment mechanism: Capitation versus fee-for-service

The main question raised in this paper is whether GPs should self select their paymentmechanism or not. To answer it, we model GPs' behavior under the most commonpayment schemes (capitation and fee-for-service) and when GPs can select one amongthose. Our analysis considers GPs heterogeneity in terms of both ability and sense ofprofessional duty. We conclude that when savings on specialists costs are the mainconcern of a regulator, GPs should be paid on a fee-for-service basis. Instead, whenfailures to identify severe conditions are the main concern, then payment self selection byGPs can be optimal.GPs; gatekeeping; payment scheme; self selection; ability; professional duty

Provider Competition in a Dynamic Setting

In this paper, we examine provider and patient behaviour where effort is non-contractible and where competition between providers is modeled in an explicit way. More specifically, we construct a model where physicians repeatedly compete for patients and where patients’ outside options are solved for in equilibrium. In our model, physicians are characterized by an individual-specific ethical constraint which allows for unobserved heterogeneity in the physicians market. By doing so, we introduce uncertainty in the patient’s likely treatment if he were in fact to leave his current physician to seek care elsewhere. We find that competition between providers may serve as an important incentive for physicians in treating their patients with desired levels of care.Physician Payment Mechanisms, Physician heterogeneity, Competition, Information Asymmetry, Insurance.

Characterization of Posidonia Oceanica Seagrass Aerenchyma through Whole Slide Imaging: A Pilot Study

Characterizing the tissue morphology and anatomy of seagrasses is essential to predicting their acoustic behavior. In this pilot study, we use histology techniques and whole slide imaging (WSI) to describe the composition and topology of the aerenchyma of an entire leaf blade in an automatic way combining the advantages of X-ray microtomography and optical microscopy. Paraffin blocks are prepared in such a way that microtome slices contain an arbitrarily large number of cross sections distributed along the full length of a blade. The sample organization in the paraffin block coupled with whole slide image analysis allows high throughput data extraction and an exhaustive characterization along the whole blade length. The core of the work are image processing algorithms that can identify cells and air lacunae (or void) from fiber strand, epidermis, mesophyll and vascular system. A set of specific features is developed to adequately describe the convexity of cells and voids where standard descriptors fail. The features scrutinize the local curvature of the object borders to allow an accurate discrimination between void and cell through machine learning. The algorithm allows to reconstruct the cells and cell membrane features that are relevant to tissue density, compressibility and rigidity. Size distribution of the different cell types and gas spaces, total biomass and total void volume fraction are then extracted from the high resolution slices to provide a complete characterization of the tissue along the leave from its base to the apex

Lithic industries, territory and mobility in the western Linear Pottery Culture

Territory is a complex notion whose definition varies depending on the discipline in which it is applied. Research on the notion of territory has often focused on the Palaeolithic. Studies in this field are mainly based on comparisons between archaeological assemblages and ethnographic data, an approach originating from the work of L.R. Binford, who introduced the concept of mobility, leading to various models of spatial occupation. How have researchers approached the notion of territory with regard to the first mixed farming populations of the Linear Pottery Culture in the Seine Basin and neighbouring regions? Can lithic industries contribute to our understanding of how these first sedentary populations perceived their territory? In this paper, we show that these first Neolithic communities likely obtained their siliceous materials via direct procurement strategies across a territory that they knew well and regularly frequented. In our study area, centred around the Rhine-Meuse region and the Seine Basin, two distinct litho-spaces are comprised of: 1) small numbers of minor territories with local resources, and 2) vast territories requiring greater mobility among the groups that occupied them. Furthermore, the procurement strategies of the occupants of the regions with few siliceous resources seem to have been based on long-distance relationships and networks. In this case, a high degree of mobility and ensuing social relations would have contributed to the attractivity of villages.Le territoire est une notion encore complexe qui recouvre des définitions polymorphes selon les disciplines. Les travaux sur la notion de territoire se sont particulièrement développés sur le Paléolithique (Delvigne 2016). Ils se fondent principalement sur des comparaisons entre les assemblages archéologiques et les données ethnographiques, issues notamment des travaux de Binford qui introduit le concept de mobilité, à l’origine de différents modèles d’occupation de l’espace (Binford 1982). Comment la notion de territoire a-t-elle été explorée pour les premières populations agro-pastorales ? L’industrie lithique peut-elle apporter des éléments sur la compréhension de la perception du territoire des premières populations sédentaires ? L’espace parcouru par ces premières communautés néolithiques pour acquérir leur matériau siliceux, selon des modalités d’acquisition directe, pourrait être entendu comme un territoire connu et traversé de manière relativement régulière. Pour notre zone d’étude, deux formes de litho-espaces se distinguent alors individualisant des petits territoires, finalement peu nombreux, où les ressources sont proches et de vastes territoires impliquant une plus forte mobilité des groupes qui les occupaient. Nous émettrons le principe que cette situation, pour les habitants de des régions pauvres en ressources, a nécessité le développement de liens et de réseaux à plus grande échelle que pour les habitats bien pourvus en ressources locales. La mobilité serait dans ce cas particulièrement régulière et avec des liens sociaux étendus, favorisant l’attractivité des villages

Strategic tradeoffs in competitor dynamics on adaptive networks

Recent empirical work highlights the heterogeneity of social competitions such as political campaigns: proponents of some ideologies seek debate and conversation, others create echo chambers. While symmetric and static network structure is typically used as a substrate to study such competitor dynamics, network structure can instead be interpreted as a signature of the competitor strategies, yielding competition dynamics on adaptive networks. Here we demonstrate that tradeoffs between aggressiveness and defensiveness (i.e., targeting adversaries vs. targeting like-minded individuals) creates paradoxical behaviour such as non-transitive dynamics. And while there is an optimal strategy in a two competitor system, three competitor systems have no such solution; the introduction of extreme strategies can easily affect the outcome of a competition, even if the extreme strategies have no chance of winning. Not only are these results reminiscent of classic paradoxical results from evolutionary game theory, but the structure of social networks created by our model can be mapped to particular forms of payoff matrices. Consequently, social structure can act as a measurable metric for social games which in turn allows us to provide a game theoretical perspective on online political debates.Comment: 20 pages (11 pages for the main text and 9 pages of supplementary material

Exact solution of bond percolation on small arbitrary graphs

We introduce a set of iterative equations that exactly solves the size distribution of components on small arbitrary graphs after the random removal of edges. We also demonstrate how these equations can be used to predict the distribution of the node partitions (i.e., the constrained distribution of the size of each component) in undirected graphs. Besides opening the way to the theoretical prediction of percolation on arbitrary graphs of large but finite size, we show how our results find application in graph theory, epidemiology, percolation and fragmentation theory.Comment: 5 pages and 3 figure

Adaptive networks: coevolution of disease and topology

Adaptive networks have been recently introduced in the context of disease propagation on complex networks. They account for the mutual interaction between the network topology and the states of the nodes. Until now, existing models have been analyzed using low-complexity analytic formalisms, revealing nevertheless some novel dynamical features. However, current methods have failed to reproduce with accuracy the simultaneous time evolution of the disease and the underlying network topology. In the framework of the adaptive SIS model of Gross et al. [Phys. Rev. Lett. 96, 208701 (2006)], we introduce an improved compartmental formalism able to handle this coevolutionary task successfully. With this approach, we analyze the interplay and outcomes of both dynamical elements, process and structure, on adaptive networks featuring different degree distributions at the initial stage.Comment: 11 pages, 8 figures, 1 appendix. To be published in Physical Review

Treatment and referral decisions under different physician payment mechanisms

International audienceThis paper analyzes and compares the incentive properties of some common payment mechanisms for GPs, namely fee for service (FFS), capitation and fundholding. It focuses on gatekeeping GPs and it specically recognizes GPs heterogeneity in both ability and altruism. It also allows inappropriate care by GPs to lead to more serious illnesses. The results are as follows. Capitation is the payment mechanism that induces the most referrals to expensive specialty care. Fundholding may induce almost as much referrals as capitation when the expected costs of GPs care are high relative to those of specialty care. Although driven by nancial incentives of different nature, the strategic behaviours associated with fundholding and FFS are very much alike. Finally, whether a regulator should use one or another payment mechanism for GPs will depend on (i) his priorities (either cost-containment or quality enhancement) which, in turn, depend on the expected cost difference between GPs care and specialty care, and (ii) the distribution of proles (diagnostic ability and altruism levels) among GPs

Modeling the dynamical interaction between epidemics on overlay networks

Epidemics seldom occur as isolated phenomena. Typically, two or more viral agents spread within the same host population and may interact dynamically with each other. We present a general model where two viral agents interact via an immunity mechanism as they propagate simultaneously on two networks connecting the same set of nodes. Exploiting a correspondence between the propagation dynamics and a dynamical process performing progressive network generation, we develop an analytic approach that accurately captures the dynamical interaction between epidemics on overlay networks. The formalism allows for overlay networks with arbitrary joint degree distribution and overlap. To illustrate the versatility of our approach, we consider a hypothetical delayed intervention scenario in which an immunizing agent is disseminated in a host population to hinder the propagation of an undesirable agent (e.g. the spread of preventive information in the context of an emerging infectious disease).Comment: Accepted for publication in Phys. Rev. E. 15 pages, 7 figure

Les caractéristiques techno-typologiques et fonctionnelles du débitage d’éclats au VSG : le cas et la place des sites hauts-normands dans le nord de la France

Depuis plusieurs années, nombre de sites du Villeneuve-Saint-Germain ont été découverts en Haute-Normandie. Résultant notamment du développement de l’archéologie préventive, cette dynamique de recherche a permis de préciser la nature des implantations au cours du Néolithique ancien mais reste toutefois à approfondir. Si le cadre chronoculturel et son évolution sont mieux définis depuis plusieurs années, nombre de données et notamment de corpus mobilier nécessiteraient une étude plus détaillée..