Mariano Jorge Levin (1951-2010)

Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM)UNIFESP, EPMSciEL

Serological diagnosis of Chagas disease with purified and defined Trypanosoma cruzi antigens

Universidade de São PauloUNIFESPUNIFESPSciEL

Mapping of B cell epitopes in an immunodominant antigen of Trypanosoma cruzi using fusions to the Escherichia coli LamB protein

The JL8 protein antigen from Trypanosoma cii , a dominant immunogen in man, has been characterized as containing tandem amino acid repeats. Here, we describe the use of the LamB protein of Escherichia coli as a carl icr of JL8 derived sequences in order to map the immunodominant B cell epitopes in this antigen. Five different sequences of JL8 were inserted in the LamB protein and the JL8-LamB fusion proteins were tested by ELISA with human chronic chagasic sera. the fusion carrying the sequence AEKQKAAEATKVAE was recognized by most sera. This protein was also capable of inhibiting the binding of human chagasic antibodies to GST-JL8 in competitive ELISA suggesting that it contains an immunodominant B cell epitope of JL8. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.Universidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilIngebi, RA-1428 Buenos Aires, DF, ArgentinaUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilWeb of Scienc

Determinants of agricultural insurance adoption: evidence from farmers in the state of São Paulo, Brazil

Purpose – The purpose of this study is to investigate the determinants of agricultural insurance adoption by farmers of the state of São Paulo, Brazil.Design/methodology/approach – Primary data from the 2015/2016 crop season was collected from a sample of 175 farmers. Logit econometric models were applied to identify the variables that affect the probability of agricultural insurance adoption.Findings – The empirical results show that the education level, access to technical assistance, use of management tools and farm size positively affect the probability of adopting agricultural insurance. In addition, farmers who produce soybean and/or corn are more likely to use insurance. On the other hand, the higher the farmers’ propensity to take risk the lower the likelihood of using insurance.Research limitations/implications – The empirical analysis is based on cross-sectional data of a sample of 175 farmers of the state of São Paulo. The use of panel data with a larger sample of farmers, considering a period of years, could provide additional information.Originality/value – To the best of the knowledge, this is the first empirical analysis about determinants of agricultural insurance adoption by Brazilian farmers, considering behavioral factors. The findings provide useful insights for policymakers in formulating risk management programs in the Brazilian agricultural markets. A better understanding about the determinants of insurance adoption is also relevant for private companies that sell insurance to farmers. Therefore, the paper may contribute with the diffusion of rural insurance as risk management tool in Brazilian agriculture

Epitope mapping of a single repetitive unit of the B13 Trypanosoma cruzi antigen as fusions to Escherichia coli LamB protein

B13, one of the immunodominant antigens of Trypanosoma cruzi, is composed of repeats of a 12-amino-acid motif. Using synthetic peptides, the sequence FGQAAAGDK was previously shown to contain the B13 immunodominant epitope recognized by chagasic patients sera. To investigate the effects of neighboring sequences in the immunodominance, we tested serum recognition of two B13 sequences fused to LamB. GDKPSPFGQAAA-LamB and FGQAAAGDKPSP-LamB were recognized, respectively, by 15% and 80% of 80 sera reactive to B13 antigen. Recognition of FGQAAAGDKPSP-LamB was inhibited by AAAGDK-containing synthetic peptides. FGQAAAGDKPSP-LamB competed with a B13 recombinant protein containing 16.6 repeats for binding to chagasic antibodies. These results strengthen previous conclusions on the immunodominant epitope of B13 and provide a comparison of two methods for epitope mapping. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Microbiological Societies.UNIFESP, Escola Paulista Med, Dept Microbiol Immunol & Parasitol, BR-01023062 São Paulo, BrazilUniv São Paulo, Inst Quim, Dept Bioquim, BR-01498 São Paulo, BrazilUniv São Paulo, Fac Med, Inst Coracao, Lab Immunol Transplantes, BR-01498 São Paulo, BrazilUNIFESP, Escola Paulista Med, Dept Microbiol Immunol & Parasitol, BR-01023062 São Paulo, BrazilWeb of Scienc

Uma análise da gestão de risco de preço por parte dos produtores de café arábica no Brasil

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOBrazilian coffee farmers use future markets in a very restricted way, which does not follow the high optimal hedge ratio observed in minimum variance models. Reasons for the low use are associated to producers and their business characteristics, their preferences about risk management tool and behavioral attitudes. In this context, the aim of this study was to examine the main factors which influence derivatives use among Brazilian coffee growers. Initially, the optimal hedge ratio was calculated with Myers and Thompson (1989) method, considering BM&FBOVESPA and ICE Futures (New York) markets. The ratio had values higher than 50%. After that, through surveys with 373 coffee farmers, it was observed that only 12.9% of the sample reported knowing and using futures as a way to manage the price risk. The hedge ratio adopted by farmers, on average, was below 50%. In a third step, a logit model was applied for data. Most important factors which explain the use of future contracts by coffee growers were risk aversion, size of production, level of understanding about future contracts and the level which farmers understand that future contracts enable the decrease of revenue fluctuation.Os mercados futuros possuem uso restrito entre os cafeicultores brasileiros, o que, de certa maneira, não condiz com as altas razões ótimas de hedge obtidas nos modelos de mínima variância. Os motivos para esta baixa utilização estão associados às características do produtor e de seu negócio, preferências em relação ao modelo de administração de risco da atividade e questões comportamentais. Diante disso, o presente estudo buscou verificar quais fatores interferem na decisão de uso destes derivativos entre os cafeicultores brasileiros. Em uma primeira etapa, foram calculadas razões ótimas de hedge, de acordo com Myers e Thompson (1989), para os mercados da BM&FBOVESPA e ICE Futures. Tais razões apresentaram valores superiores a 50%. Em uma segunda etapa, a partir da aplicação de 373 questionários, observou-se que 12,9% da amostra declara conhecer e utilizar futuros, sendo que, na média, a razão de hedge adotada esteve abaixo de 50%. Em uma terceira etapa, a partir de um modelo logit, concluiu-se que os fatores que influenciaram o uso dos contratos foram grau de aversão ao risco de preço, tamanho da produção, nível de conhecimento sobre derivativos e dimensão pela qual se entende que tais instrumentos levam à maior estabilidade da receita da atividade.Os mercados futuros possuem uso restrito entre os cafeicultores brasileiros, o que, de certa maneira, não condiz com as altas razões ótimas de hedge obtidas nos modelos de mínima variância. Os motivos para esta baixa utilização estão associados às características do produtor e de seu negócio, preferências em relação ao modelo de administração de risco da atividade e questões comportamentais. Diante disso, o presente estudo buscou verificar quais fatores interferem na decisão de uso destes derivativos entre os cafeicultores brasileiros. Em uma primeira etapa, foram calculadas razões ótimas de hedge, de acordo com Myers e Thompson (1989), para os mercados da BM&FBOVESPA e ICE Futures. Tais razões apresentaram valores superiores a 50%. Em uma segunda etapa, a partir da aplicação de 373 questionários, observou-se que 12,9% da amostra declara conhecer e utilizar futuros, sendo que, na média, a razão de hedge adotada esteve abaixo de 50%. Em uma terceira etapa, a partir de um modelo logit, concluiu-se que os fatores que influenciaram o uso dos contratos foram grau de aversão ao risco de preço, tamanho da produção, nível de conhecimento sobre derivativos e dimensão pela qual se entende que tais instrumentos levam à maior estabilidade da receita da atividade503397410FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOBrazilian coffee farmers use future markets in a very restricted way, which does not follow the high optimal hedge ratio observed in minimum variance models. Reasons for the low use are associated to producers and their business characteristics, their preferences about risk management tool and behavioral attitudes. In this context, the aim of this study was to examine the main factors which influence derivatives use among Brazilian coffee growers. Initially, the optimal hedge ratio was calculated with Myers and Thompson (1989) method, considering BM&FBOVESPA and ICE Futures (New York) markets. The ratio had values higher than 50%. After that, through surveys with 373 coffee farmers, it was observed that only 12.9% of the sample reported knowing and using futures as a way to manage the price risk. The hedge ratio adopted by farmers, on average, was below 50%. In a third step, a logit model was applied for data. Most important factors which explain the use of future contracts by coffee growers were risk aversion, size of production, level of understanding about future contracts and the level which farmers understand that future contracts enable the decrease of revenue fluctuatio

Uma análise da gestão de risco de preço por parte dos produtores de café arábica no Brasil

Os mercados futuros possuem uso restrito entre os cafeicultores brasileiros, o que, de certa maneira, não condiz com as altas razões ótimas de hedge obtidas nos modelos de mínima variância. Os motivos para esta baixa utilização estão associados às características do produtor e de seu negócio, preferências em relação ao modelo de administração de risco da atividade e questões comportamentais. Diante disso, o presente estudo buscou verificar quais fatores interferem na decisão de uso destes derivativos entre os cafeicultores brasileiros. Em uma primeira etapa, foram calculadas razões ótimas de hedge, de acordo com Myers e Thompson (1989), para os mercados da BM&FBOVESPA e ICE Futures. Tais razões apresentaram valores superiores a 50%. Em uma segunda etapa, a partir da aplicação de 373 questionários, observou-se que 12,9% da amostra declara conhecer e utilizar futuros, sendo que, na média, a razão de hedge adotada esteve abaixo de 50%. Em uma terceira etapa, a partir de um modelo logit, concluiu-se que os fatores que influenciaram o uso dos contratos foram grau de aversão ao risco de preço, tamanho da produção, nível de conhecimento sobre derivativos e dimensão pela qual se entende que tais instrumentos levam à maior estabilidade da receita da atividade

Two-dimensional radiographs versus cone-beam computed tomography in planning mini-implant placement : a systematic review

This study aimed to compare two-dimensional radiographs and cone beam computed tomography (CBCT) images for mini-implant planning. A search was performed in PubMed, Embase, Web of Science, Cochrane Library and Google Scholar electronic databases accord