Platform Pricing Structure and Moral Hazard

We study pricing by a monopoly platform that matches buyers and sellers in an environment with cross-market externalities. Said platform has no private information, does not set the commodity's price and can only charge trading parties for the transaction. Our innovation consists in introducing moral hazard on the sellers' side and an equilibrium notion of platform reputation in an infinite horizon model. With linear fees the platform can mitigate, but not eliminate, the loss of reputation induced by moral hazard. If lump-sum fees (registration fees) can be levied, moral hazard can be overcome. The upfront payment determines the participation threshold of sellers and extracts them, while (lower) transactions fees provide incentives for good behavior. This breaks the equivalence of lump-sum payments and linear fees (Rochet and Tirole (2006)). We draw implications for the role of subsidies (Caillaud and Jullien (2003)).Platforms; Two-Sided Markets; Reputation; Moral Hazard

Diretório Nacional de pesquisadores de trigo.

Tecnicos; Indice de autor; Indice por area de atuacao; Indice geografico.bitstream/item/65907/1/CPAO-DOC.-48-91.pd

Therapeutic Approach to Parapneumonic Effusions and Empyemas

Face à inexistência de uma metodologia única e consensual na abordagem terapêutica dos derrames pleurais parapneumónicos e empiemas, os autores propõem um protocolo de orientação, que resultou da reflexão baseada na sua experiência e na bibliografia mais recente

LINFOPENIA T CD4 NO LUPUS ERITEMATOSO SISTÉMICO

Abstract: Background: Systemic Lupus Erythematosus (SLE) is an inflammatory chronic disease characterized by the presence of autoantibodies, immunocomplex production and organ injury. Several alterations of the immune system have been described, namely of CD4 T cells, with particular focus on regulatory subgroup. Objective: Quantify peripheral CD4 T cells in a population of patients with SLE and correlate it with lupus activity, affected organs, therapeutics and infections. Methods: Retrospective study involving all SLE patients seen in the clinical immunology outpatient clinic of the Hospital Geral Santo António, Porto that has done some peripheral blood flow cytometry study. Results: Twenty-nine patients have been evaluated, 16 were taking glucocorticoids and six immunossupressors. The mean SLEDAI at the study time was nine and the ECLAM was three. Thirty-one percent of the patients had leukopenia, 76% lymphocytopenia and the same number CD4 depletion. Fifty-five percent of the patients had CD4 levels lower than 500/mm3, 31% lower than 200/mm3. All patients with SLEDAI ?20 and ECLAM ?4 had CD4 counts inferior to 500/mm3 and all patients with inactive disease had CD4 superior to 500/mm3. There have been three opportunistic infections: cryptococcal meningitis, pulmonary aspergilosis, Pneumocystis jirovecii pneumonia, all in patients with CD4 counts lower than 500/mm3. Conclusion: Decreased CD4 T cells counts have been very common in this study population. There is an inverse relation between CD4 cells counts and disease activity. Opportunistic infections occurred in patients with severe CD4 depletion. Keywords: Systemic Lupus Erythematosus; CD4 T Lymphocytes; Lymphocytopenia; SLE Activity; Opportunistic infection

LINFOPENIA T CD4 NO LUPUS ERITEMATOSO SISTÉMICO

Abstract: Background: Systemic Lupus Erythematosus (SLE) is an inflammatory chronic disease characterized by the presence of autoantibodies, immunocomplex production and organ injury. Several alterations of the immune system have been described, namely of CD4 T cells, with particular focus on regulatory subgroup. Objective: Quantify peripheral CD4 T cells in a population of patients with SLE and correlate it with lupus activity, affected organs, therapeutics and infections. Methods: Retrospective study involving all SLE patients seen in the clinical immunology outpatient clinic of the Hospital Geral Santo António, Porto that has done some peripheral blood flow cytometry study. Results: Twenty-nine patients have been evaluated, 16 were taking glucocorticoids and six immunossupressors. The mean SLEDAI at the study time was nine and the ECLAM was three. Thirty-one percent of the patients had leukopenia, 76% lymphocytopenia and the same number CD4 depletion. Fifty-five percent of the patients had CD4 levels lower than 500/mm3, 31% lower than 200/mm3. All patients with SLEDAI ?20 and ECLAM ?4 had CD4 counts inferior to 500/mm3 and all patients with inactive disease had CD4 superior to 500/mm3. There have been three opportunistic infections: cryptococcal meningitis, pulmonary aspergilosis, Pneumocystis jirovecii pneumonia, all in patients with CD4 counts lower than 500/mm3. Conclusion: Decreased CD4 T cells counts have been very common in this study population. There is an inverse relation between CD4 cells counts and disease activity. Opportunistic infections occurred in patients with severe CD4 depletion. Keywords: Systemic Lupus Erythematosus; CD4 T Lymphocytes; Lymphocytopenia; SLE Activity; Opportunistic infection

Fine-root production in two secondary forest sites with distinct ages in Eastern Amazon.

O objetivo deste trabalho foi avaliar a dinâmica de produção de raízes finas (diâmetro ≤ 2 mm) em duas áreas de floresta secundária com diferentes idades. A produção de raízes finas foi monitorada utilizando a técnica de ingrowth core em um sítio com 18 anos de idade (2 ha) e um outro sítio com 10 anos de idade (0,5 ha), localizados na região de Apeú, nordeste do Estado do Pará. Os sítios foram abandonados depois de sucessivos ciclos agrícolas, iniciados em 1940. A produção mensal de raízes vivas foi semelhante entre os sítios e influenciada pela sazonalidade pluviométrica, com maior produção durante a estação seca para massa e comprimento. No entanto, a mortalidade, em termos de massa, foi maior no sítio de 10 anos. A sazonalidade influenciou a mortalidade somente no sítio de 18 anos, seguindo o padrão observado para as raízes vivas. A influência sazonal sobre a mortalidade em termos de comprimento foi diferente entre os sítios, com maior mortalidade durante a estação chuvosa no sítio de 10 anos e maior mortalidade durante a estação seca no sítio de 18 anos. O comprimento radicular específico foi maior durante a estação chuvosa e influenciado pelos sítios, sendo maior no sítio de 10 anos. A produção de raízes finas não foi influenciada pela cronossequência dos sítios estudados, provavelmente porque a produção de raízes finas pode ter estabilizado nos sítios ou depende mais das condições de clima e solo. A produção, em termos de massa e comprimento, foram indicadores que geralmente mostraram o mesmo padrão

Are Anti-Ro52 Antibodies Associated with Pulmonary Involvement in Scleroderma?

Abstract Introduction: The presence of anti-Ro52 antibodies has been reported in a wide variety of autoimmune diseases, particularly in myositis, scleroderma and autoimmune liver diseases. Clinical significance of anti-Ro52 antibodies remains controversial. Studies are lacking in clarifying the association of anti-Ro52 with pulmonary involvement in scleroderma. Objectives: To determine if anti-Ro52 antibodies are associated with pulmonary involvement (interstitial, indirect pulmonary hypertension, or both) in scleroderma. Methods: Single center, retrospective study based on immunoblotting panel analysis and patients clinical records. Pulmonary manifestations were sub-grouped in: 1) interstitial (alveolitis and/or fibrosis), 2) pulmonary artery systolic pressure (PASP) ≥40 mmHg plus interstitial pulmonary disease, and 3) isolated PASP≥40 mmHg (purely vascular). Results: Our scleroderma cohort included 200 patients, of which 137 had immunoblotting panels with anti-Ro52 reactivity analysis. The search was conducted between January 2010 and July 2011. The frequency of pulmonary manifestations in patients with positive anti-Ro52 antibodies was 67.7% (n=31), and 60% (n=24) in the negative anti-Ro52 group, showing no significant differences between groups (p=0.621). Still no significant differences were found when pulmonary manifestations were evaluated according to the subgroups (p=0.525). Sensitivity, specificity, positive and negative predictive values of anti-Ro52 reactivity for determining pulmonary involvement in scleroderma were low. Conclusion: No association was found between positive anti-Ro52 antibodies and pulmonary involvement in scleroderma