123 research outputs found

    Habitat Fragmentation, Variable Edge Effects, and the Landscape-Divergence Hypothesis

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    Edge effects are major drivers of change in many fragmented landscapes, but are often highly variable in space and time. Here we assess variability in edge effects altering Amazon forest dynamics, plant community composition, invading species, and carbon storage, in the world's largest and longest-running experimental study of habitat fragmentation. Despite detailed knowledge of local landscape conditions, spatial variability in edge effects was only partially foreseeable: relatively predictable effects were caused by the differing proximity of plots to forest edge and varying matrix vegetation, but windstorms generated much random variability. Temporal variability in edge phenomena was also only partially predictable: forest dynamics varied somewhat with fragment age, but also fluctuated markedly over time, evidently because of sporadic droughts and windstorms. Given the acute sensitivity of habitat fragments to local landscape and weather dynamics, we predict that fragments within the same landscape will tend to converge in species composition, whereas those in different landscapes will diverge in composition. This ‘landscape-divergence hypothesis’, if generally valid, will have key implications for biodiversity-conservation strategies and for understanding the dynamics of fragmented ecosystems

    Indirect reciprocity and the evolution of “moral signals”

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    Signals regarding the behavior of others are an essential element of human moral systems and there are important evolutionary connections between language and large-scale cooperation. In particular, social communication may be required for the reputation tracking needed to stabilize indirect reciprocity. Additionally, scholars have suggested that the benefits of indirect reciprocity may have been important for the evolution of language and that social signals may have coevolved with large-scale cooperation. This paper investigates the possibility of such a coevolution. Using the tools of evolutionary game theory, we present a model that incorporates primitive “moral signaling” into a simple setting of indirect reciprocity. This model reveals some potential difficulties for the evolution of “moral signals.” We find that it is possible for “moral signals” to evolve alongside indirect reciprocity, but without some external pressure aiding the evolution of a signaling system, such a coevolution is unlikely

    Mid- and long-term clinical results of surgical therapy in unicameral bone cysts

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    <p>Abstract</p> <p>Background</p> <p>Unicameral (or simple) bone cysts (UBC) are benign tumours most often located in long bones of children and adolescents. Pathological fractures are common, and due to high recurrence rates, these lesions remain a challenge to treat. Numerous surgical procedures have been proposed, but there is no general consensus of the ideal treatment. The aim of this investigation therefore was to study the long-term outcome after surgical treatment in UBC.</p> <p>Methods</p> <p>A retrospective analysis of 46 patients surgically treated for UBC was performed for short and mid-term outcome. Clinical and radiological outcome parameters were studied according to a modified Neer classification system. Long-term clinical information was retrieved via a questionnaire at a minimum follow-up of 10 years after surgery.</p> <p>Results</p> <p>Forty-six patients (17 female, 29 male) with a mean age of 10.0 ± 4.8 years and with histopathologically confirmed diagnosis of UBC were included. Pathological fractures were observed in 21 cases (46%). All patients underwent surgery for UBC (35 patients underwent curettage and bone grafting as a primary therapy, 4 curettage alone, 3 received corticoid instillation and 4 decompression by cannulated screws). Overall recurrence rate after the first surgical treatment was 39% (18/46), second (17.4% of all patients) and third recurrence (4.3%) were frequently observed and were addressed by revision surgery. Recurrence was significantly higher in young and in male patients as well as in active cysts. After a mean of 52 months, 40 out of 46 cysts were considered healed. Prognosis was significantly better when recurrence was observed later than 30 months after therapy. After a mean follow-up of 15.5 ± 6.2 years, 40 patients acknowledged clinically excellent results, while five reported mild and casual pain. Only one patient reported a mild limitation of range of motion.</p> <p>Conclusions</p> <p>Our results suggest satisfactory overall long-term outcome for the surgical treatment of UBC, although short-and mid-term observation show a considerable rate of recurrence independent of the surgical technique.</p

    Metaethics, teleosemantics and the function of moral judgements

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    This paper applies the theory of teleosemantics to the issue of moral content. Two versions of teleosemantics are distinguished: input-based and output-based. It is argued that applying either to the case of moral judgements generates the conclusion that such judgements have both descriptive (belief-like) and directive (desire-like) content, intimately entwined. This conclusion directly validates neither descriptivism nor expressivism, but the application of teleosemantics to moral content does leave the descriptivist with explanatory challenges which the expressivist does not face. Since teleosemantics ties content to function, the paper also offers an account of the evolutionary function of moral judgements

    Perfil do cirurgiĂŁo de coluna brasileiro

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    OBJECTIVE: To conduct cross-sectional study identifying the profile of the Brazilian spinal surgeon. METHODS: Data were collected through a questionnaire with multiple alternatives during two major events for spine surgery at national level in 2011, the Congresso da Sociedade Brasileira de Coluna (Congress of the Brazilian Spine Society) and SimpĂłsio Internacional de Coluna (International Spine Symposium, SINCOL). The data were submitted to statistical analysis comparing and stratifying the information obtained according to the profile. RESULTS: We obtained 182 questionnaires answered by orthopedists and neurosurgeons with peculiarities and similarities on their medical management. CONCLUSIONS: The data obtained in this study may be important for the development of health policies in the spine surgery in Brazil.OBJETIVO: Llevar a cabo estudio transversal para identificar el perfil del cirujano de columna en Brasil. MÉTODOS: Los datos fueron recolectados por medio de cuestionarios con opciones mĂșltiples, en dos eventos de relevancia para la cirugĂ­a de columna vertebral, a nivel nacional en 2011, Congreso Brasileño de la Sociedad Brasileña de Columna (SBC) y el Simposio Internacional de Columna (SINCOL). Los datos fueron sometidos a anĂĄlisis estadĂ­stico, comparĂĄndose y estratificĂĄndose las informaciones obtenidas, de acuerdo con el perfil encontrado. RESULTADOS: Se obtuvieron cuestionarios respondidos por 182 ortopedistas y neurocirujanos, con particularidades y similitudes en sus actividades mĂ©dicas. CONCLUSIONES: Los datos obtenidos en este estudio pueden ser importantes para el desarrollo de polĂ­ticas de salud en el ĂĄrea de la cirugĂ­a de columna en Brasil.OBJETIVO: Realizar estudo transversal identificando o perfil do cirurgiĂŁo de coluna no Brasil. MÉTODOS: Foram coletados dados por meio de questionĂĄrios com mĂșltiplas alternativas, em dois eventos de relevĂąncia para a cirurgia de coluna no Ăąmbito nacional em 2011, o Congresso da Sociedade Brasileira de Coluna (SBC) e o SimpĂłsio Internacional de Coluna (SINCOL). Os dados foram submetidos a anĂĄlise estatĂ­stica comparando e estratificando as informaçÔes obtidas conforme o perfil encontrado. RESULTADOS: Obtivemos 182 questionĂĄrios respondidos por ortopedistas e neurocirurgiĂ”es com particularidades e semelhanças em suas condutas mĂ©dicas. CONCLUSÕES: Os dados obtidos nessa pesquisa podem ser importantes para o desenvolvimento de polĂ­ticas de saĂșde na ĂĄrea de cirurgia de coluna no Brasil.Universidade Federal de SĂŁo Paulo (UNIFESP) Departamento de Ortopedia e TraumatologiaUNIFESP, Depto. de Ortopedia e TraumatologiaSciEL

    Brain homeostasis: VEGF receptor 1 and 2—two unequal brothers in mind

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