統計力學の諸問題

Selective predation can lead to natural selection in prey populations and may alleviate competition among surviving individuals. The processes of selection and competition can have substantial effects on prey population dynamics, but are rarely studied simultaneously. Moreover, field studies of predator-induced short-term selection pressures on prey populations are scarce. Here we report measurements of density dependence in body composition in a bivalve prey (edible cockle, Cerastoderma edule) during bouts of intense predation by an avian predator (red knot, Calidris canutus). We measured densities, patchiness, morphology, and body composition (shell and flesh mass) of cockles in a quasi-experimental setting, i.e. before and after predation in three similar plots of 1 ha each, two of which experienced predation, and one of which remained unvisited in the course of the short study period and served as a reference. An individual's shell and flesh mass declined with cockle density (negative density dependence). Before predation, cockles were patchily distributed. After predation, during which densities were reduced by 78% (from 232 m-2 to 50 m-2), the patchiness was substantially reduced, i.e. the spatial distribution was homogenized. Red knots selected juvenile cockles with an average length of 6.9 mm (SD 1.0). Cockles surviving predation had heavier shells than before predation (an increase of 21.5 percentage points), but similar flesh masses. By contrast, in the reference plot shell mass did not differ statistically between initial and final sampling occasions, while flesh mass was larger (an increase of 13.2 percentage points). In this field-study, we show that red knots imposed a strong selection pressure on cockles to grow fast with thick shells and little flesh mass, with selection gradients among the highest reported in the literature

On classical q-deformations of integrable sigma-models

JHEP is an open-access journal funded by SCOAP3 and licensed under CC BY 4.0A procedure is developed for constructing deformations of integrable σ-models which are themselves classically integrable. When applied to the principal chiral model on any compact Lie group F, one recovers the Yang-Baxter σ-model introduced a few years ago by C. Klimčík. In the case of the symmetric space σ-model on F/G we obtain a new one-parameter family of integrable σ-models. The actions of these models correspond to a deformation of the target space geometry and include a torsion term. An interesting feature of the construction is the q-deformation of the symmetry corresponding to left multiplication in the original models, which becomes replaced by a classical q-deformed Poisson-Hopf algebra. Another noteworthy aspect of the deformation in the coset σ-model case is that it interpolates between a compact and a non-compact symmetric space. This is exemplified in the case of the SU(2)/U(1) coset σ-model which interpolates all the way to the SU(1, 1)/U(1) coset σ-modelPeer reviewedFinal Published versio

Improving Receipt and Preventive Care Delivery for Adolescents and Young Adults: Initial Lessons from Top-Performing States

Purpose Provisions of the Patient Protection and Affordable Care Act (ACA) of 2010 hold promise for improving access to and receipt of preventive services for adolescents and young adults (AYAs). The Title V Block Grant transformation also includes a focus on improving adolescent preventive care. This brief report describes and discusses an inquiry of promising strategies for improving access and preventive care delivery identified in selected high-performing states. Methods Two data sources were used to identify top-performing states in insurance enrollment and preventive care delivery: National Survey of Children's Health for adolescents (ages 12-17 years) and Behavioral Risk Factors Surveillance System for young adults (ages 18-25 years). Interviews were conducted with key stakeholders to identify promising strategies related to increasing AYAs' insurance enrollment and receipt of preventive services. Results Seven top-performing states were selected: California, Colorado, Illinois, Iowa, Oregon, Vermont, and Texas; 27 stakeholders completed interviews. Four strategies were identified regarding insurance enrollment: use of partnerships; special populations outreach; leveraging laws and resources; and youth engagement. Four strategies were identified regarding quality preventive care: expand provider capacity to serve AYAs; adopt medical home policies; establish quality improvement projects; and enhance consumer awareness of well-visit. States focused more on adolescents than young adults and on increasing health insurance enrollment than the provision of preventive services. Conclusions This commentary identifies strategies and recommends areas for future action, as Title V programs and their partners focus on improving healthcare for AYAs as ACA implementation and the Title V transformation continues

Phylogenetic Analysis Supports Horizontal Transmission as a Driving Force of the Spread of Avian Bornaviruses

Background Avian bornaviruses are a genetically diverse group of viruses initially discovered in 2008. They are known to infect several avian orders. Bornaviruses of parrots and related species (Psittaciformes) are causative agents of proventricular dilatation disease, a chronic and often fatal neurologic disease widely distributed in captive psittacine populations. Although knowledge has considerably increased in the past years, many aspects of the biology of avian bornaviruses are still undiscovered. In particular, the precise way of transmission remains unknown. Aims and Methods In order to collect further information on the epidemiology of bornavirus infections in birds we collected samples from captive and free-ranging aquatic birds (n = 738) and Passeriformes (n = 145) in Germany and tested them for the presence of bornaviruses by PCR assays covering a broad range of known bornaviruses. We detected aquatic bird bornavirus 1 (ABBV-1) in three out of 73 sampled free-ranging mute swans (Cygnus olor) and one out of 282 free-ranging Eurasian oystercatchers (Haematopus ostralegus). Canary bornavirus 1 (CnBV-1), CnBV-2 and CnBV-3 were detected in four, six and one out of 48 captive common canaries (Serinus canaria forma domestica), respectively. In addition, samples originating from 49 bornavirus-positive captive Psittaciformes were used for determination of parrot bornavirus 2 (PaBV-2) and PaBV-4 sequences. Bornavirus sequences compiled during this study were used for phylogenetic analysis together with all related sequences available in GenBank. Results of the Study Within ABBV-1, PaBV-2 and PaBV-4, identical or genetically closely related bornavirus sequences were found in parallel in various different avian species, suggesting that interspecies transmission is frequent relative to the overall transmission of these viruses. Our results argue for an important role of horizontal transmission, but do not exclude the additional possibility of vertical transmission. Furthermore we defined clearly separated sequence clusters within several avian bornaviruses, providing a basis for an improved interpretation of transmission events within and between wild bird populations and captive bird collections

Sport, Christianity and Social Justice? Considering a Theological Foundation

Following recent debates on the relationship between “God,” “ethics,” and issues of “social justice” within sporting locales, this article contends that Christian ethics and the biblical mandate of social justice have important contributions to make to broader understandings of sport and sport ethics. The aim of the article is to: (a) map the emergence of the concept of social justice within academic, social, and political discourse; (b) examine the metaphysical anchors of sport ethics; (c) explore how a Christian framework of metaphysics might be understood within sport and sport ethics; and (d) highlight how key dimensions of the sporting experience, i.e., play and embodiment, might impact theological understandings of ethics and social justice. The article concludes by suggesting that a Christian metaphysical vision has much to offer in reforming sport by grounding it within a Trinitarian theology, borne out of a biblical description of a perfectly “just,” Creator God