958 resultados para Open University of Brazil
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O HTLV foi descrito inicialmente associado a uma leucemia no Japão e a uma doença neurológica presente no Caribe. Logo foi evidenciado que o HTLV-II era endêmico entre Ameríndios e, particularmente, entre Índios brasileiros. A Amazônia brasileira é a maior área endêmica para o vírus e dessa forma, permitiu que fossem realizados vários estudos relacionados com a sua biologia, a busca de doença, informações epidemiológicas que incluíram uma bem definida distribuição geográfica, a definição dos modos de transmissão e manutenção do vírus em comunidades pequenas, epidemiologicamente fechadas, assim como contribuições para o diagnóstico laboratorial da infecção. Um novo subtipo molecular, denominado HTLV-IIc, foi adicionalmente descrito baseando-se no sequenciamento genético do vírus e na análise filogenética. Esse subtipo está presente em outras áreas do país, indicando que o HTLV também funciona como um marcador precioso das migrações humanas nas Américas no passado e um provável marcador dos costumes das populações atuais. O outro retrovírus humano, o HIV, ainda não é prevalente nas comunidades indígenas, apesar de que elas podem ser facilmente alcançadas em virtude das inúmeras facilidades de transmissão para o vírus.
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A pesca artesanal na costa Norte do Brasil é caracterizado por um conjunto de modalidades de pesca diferentes. Utilizando uma abordagem multidisciplinar, 20 sistemas de produção pesqueira foram identificados, com características distintas em relação à tecnologia e finalidade. As características de cada sistema foram classificados em cinco dimensões (ecológicas, económicas, sociais, tecnológicos e políticos). A análise de escalonamento multidimensional revelou que alguns destes 20 sistemas têm semelhanças maiores. Assim, um total de 10 grupos distintos foram identificados.
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A distribuição espacial e temporal da densidade e biomassa dos copépodos planctônicos Pseudodiaptomus richardi e P. acutus, ao longo de um gradiente de salinidade, foi estudada no Estuário do Rio Caeté (Norte do Brasil) durante os meses de junho e dezembro de 1998 (estação seca) e fevereiro e maio de 1999 (estação chuvosa). A biomassa dos copépodos foi estimada a partir de parâmetros da regressão baseada na relação entre o peso seco e o comprimento do corpo (prossoma) de organismos adultos. O Estuário do Rio Caeté caracterizou-se por uma grande variação espacial e sazonal na salinidade (0,8-37,2). A relação peso-comprimento para ambas as espécies de Pseudodiaptomus foi do tipo exponencial. Os valores de densidade e biomassa oscilaram entre 0,28-46,18 ind. m-3 e 0,0022-0,3507 mg DW. m-3 para P. richardi; e entre 0,01-17,02 ind. m-3 e 0,0005-0,7181 mg DW. m-3 para P. acutus. Os resultados revelaram que a contribuição de P. richardi para a produção secundária no Estuário do Rio Caeté é mais importante na zona liminética que em outras zonas onde foram dominantes os regimes eurihalino-polihalino. Contudo, para P. acutus não foi possível observar de forma clara um padrão de distribuição espacial e temporal para a área estudada.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The objective of this work is to study the relation between humidity, density, porosity and shrinkage of the floodplain soil and riparian vegetation and their ability to store water. For this purpose, two locations for every type of soils were evaluated. Both were placed at the Agronomy University (Faculdade de Ciências Agronômicas) in São Manuel, State of São Paulo, Brazil. The floodplain soil was vegetated with Southern Cattail (Typha domingensis). In both places, soil samples were collected from several depths: 0, 30, 60 and 100 cm. Results show that lower soil density values (0.15 g/cm3) with organic texture and high porosities values (up to 86.2%) were found in samples with the highest organic material content in the floodplain soil. For this field experiment, flood plains soils (characterised as basin gley soils) presented high volumetric instability with a retratibility of 67.49% and higher water storage capacities compared to riparian stands soils (characterised as fluvic neosoils).
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There are few environmental studies using biomarkers for the species Atherinella brasiliensis in Brazil. In the present work, the presence of hepatic histopathological lesions and nuclear abnormalities in erythrocytes were investigated in A. brasiliensis from Lamberto, a beach under influence of domestic wastes and marine activities. For comparison, fish were also sampled in Puruba, a non-polluted beach, located in the northeastern of Sao Paulo State. The frequency of lesions found in liver was in higher numbers in individuals from Lamberto than Puruba beach. The most critical injuries observed in A. brasiliensis were the presence of necrotic areas, leucocytes infiltration and piknotic nucleus. A high occurrence of cells with vacuolization was also observed. The hepatic lesion index of the fish from Lamberto beach showed significant high values (I(org)=13) when compared with fish from Puruba beach (I(org)=7) suggesting the influence of the several human activities in the studied site. Notched and blebed nucleous were observed in this study, and significant differences were found between the studied sites. However, these differences did not reflect the total nuclear alterations.
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A survey of Microsporum gypseum was conducted in soil samples in different geographical regions of Brazil. The isolation of dermatophyte from soil samples was performed by hair baiting technique and the species were identified by morphology studies. We analyzed 692 soil samples and the recuperating rate was 19.2%. The activities of keratinase and elastase were quantitatively performed in 138 samples. The sequencing of the ITS region of rDNA was performed in representatives samples. M. gypseum isolates showed significant quantitative differences in the expression of both keratinase and elastase, but no significant correlation was observed between these enzymes. The sequencing of the representative samples revealed the presence of two teleomorphic species of M. gypseum (Arthroderma gypseum and A. incurvatum). The enzymatic activities may play an important role in the pathogenicity and a probable adaptation of this fungus to the animal parasitism. Using the phenotypical and molecular analysis, the Microsporum identification and their teleomorphic states will provide a useful and reliable identification system.
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Abstract Background The naturally-acquired immune response to Plasmodium vivax variant antigens (VIR) was evaluated in individuals exposed to malaria and living in different endemic areas for malaria in the north of Brazil. Methods Seven recombinant proteins representing four vir subfamilies (A, B, C, and E) obtained from a single patient from the Amazon Region were expressed in Escherichia coli as soluble glutathione S-transferase fusion proteins. The different recombinant proteins were compared by ELISA with regard to the recognition by IgM, IgG, and IgG subclass of antibodies from 200 individuals with patent infection. Results The frequency of individuals that presented antibodies anti-VIR (IgM plus IgG) during the infection was 49%. The frequencies of individuals that presented IgM or IgG antibodies anti-VIR were 29.6% or 26.0%, respectively. The prevalence of IgG antibodies against recombinant VIR proteins was significantly lower than the prevalence of antibodies against the recombinant proteins representing two surface antigens of merozoites of P. vivax: AMA-1 and MSP119 (57.0% and 90.5%, respectively). The cellular immune response to VIR antigens was evaluated by in vitro proliferative assays in mononuclear cells of the individuals recently exposed to P. vivax. No significant proliferative response to these antigens was observed when comparing malaria-exposed to non-exposed individuals. Conclusion This study provides evidence that there is a low frequency of individuals responding to each VIR antigens in endemic areas of Brazil. This fact may explain the host susceptibility to new episodes of the disease.
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Abstract Background Plasmodium vivax merozoite surface protein-1 (MSP-1) is an antigen considered to be one of the leading malaria vaccine candidates. PvMSP-1 is highly immunogenic and evidences suggest that it is target for protective immunity against asexual blood stages of malaria parasites. Thus, this study aims to evaluate the acquired cellular and antibody immune responses against PvMSP-1 in individuals naturally exposed to malaria infections in a malaria-endemic area in the north-eastern Amazon region of Brazil. Methods The study was carried out in Paragominas, Pará State, in the Brazilian Amazon. Blood samples were collected from 35 individuals with uncomplicated malaria. Peripheral blood mononuclear cells were isolated and the cellular proliferation and activation was analysed in presence of 19 kDa fragment of MSP-1 (PvMSP-119) and Plasmodium falciparum PSS1 crude antigen. Antibodies IgE, IgM, IgG and IgG subclass and the levels of TNF, IFN-γ and IL-10 were measured by enzyme-linked immunosorbent assay. Results The prevalence of activated CD4+ was greater than CD8+ T cells, in both ex-vivo and in 96 h culture in presence of PvMSP-119 and PSS1 antigen. A low proliferative response against PvMSP-119 and PSS1 crude antigen after 96 h culture was observed. High plasmatic levels of IFN-γ and IL-10 as well as lower TNF levels were also detected in malaria patients. However, in the 96 h supernatant culture, the dynamics of cytokine responses differed from those depicted on plasma assays; in presence of PvMSP-119 stimulus, higher levels of TNF were noted in supernatant 96 h culture of malaria patient’s cells while low levels of IFN-γ and IL-10 were verified. High frequency of malaria patients presenting antibodies against PvMSP-119 was evidenced, regardless class or IgG subclass.PvMSP-119-induced antibodies were predominantly on non-cytophilic subclasses. Conclusions The results presented here shows that PvMSP-119 was able to induce a high cellular activation, leading to production of TNF and emphasizes the high immunogenicity of PvMSP-119 in naturally exposed individuals and, therefore, its potential as a malaria vaccine candidate.
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The transposition of the São Francisco River is considered one of the greatest engineering works in Brazil of all time since it will cross an extensive agricultural region of continental dimensions, involving environmental impacts, water, soil, irrigation, water payment and other multidisciplinary themes. Taking into account its importance, this subject was incorporated into a discipline of UFSCar (Federal University of São Carlos - Brazil) named "Pollution and Environmental Impacts". It was noted strong reaction against the project, even before the presentation. To allow a critical analysis, the first objective was to compile the main technical data and environmental impacts. The second objective was to detect the three most important aspects that cause reaction, concluding for the following reasons: assumption that the volume of water to be transferred was much greater than it actually is proposed in the project; lack of knowledge about similar project already done in Brazil; the idea that the artificial canal to be built was much broader than that proposed by the project. The participants' opinion about "volume to be transferred" was raised quantitatively four times: 2-undergraduate students; 1-graduate; 1-outside community. The average resulted 14 times larger than that proposed in the project, significant according to t-test. It was concluded that the reaction to water transfer project is due in part to the ignorance combined with a preconceived idea that tend to overestimate the magnitude of environmental impacts.
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Background Apart from compulsory lectures on classical homeopathy (CH), traditional Chinese medicine/acupuncture, neural therapy and anthroposophically extended medicine (AEM), our institute at the University of Bern offers several optional practical courses for medical students. The aim of this course during autumn 2011 and spring 2012 was to discuss basic research, observational and clinical studies in the fields of CH and AEM, so that students i) learned how to read and appraise scientific publications, ii) learned how complementary medicine can be investigated with scientific methods, and iii) were able to form their own opinion about the possible specific effects and effectiveness of homeopathically potentised substances. Methods Introductory lectures on AEM, CH and study design were given to 12 second year medical students. The students appraised 12 research articles and presented the results in class, followed by discussions with experts in the fields of basic and clinical research from our institute. A company producing homeopathic remedies was visited and students could practise potentization procedures and trituration. At the end of the course, students compiled posters with arguments in favour of and against specific effects and effectiveness as well as their own conclusions. The course was evaluated using a written questionnaire with closed and open questions. Results Previous knowledge about CH and AEM was scarce among the students. It slightly increased during the course, and the course itself fostered their interest on the topic. This course was chosen by most students, because they were genuinely interested in the topic (and not because other courses they had wanted to visit were fully booked). The students especially valued the discussions, the various perspectives presented to them, and experiencing a potentization process. Conclusion Medical students were interested to learn more about homeopathically potentised substances. The contradictory study results made it difficult for them to form their own opinion. Apart from appraising articles, the students would have liked to meet and talk to patients.
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By March, 1936, the University of Missouri formally rejected Gaines because Missouri law would not permit a person of African descent to enter a white school. Within three weeks, the NAACP petitioned the court asking the University of Missouri to open its doors to Gaines on the grounds that it was the only public law school in Missouri.