861 resultados para State of knowledge
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In this article, we review the state-of-the-art techniques in mining data streams for mobile and ubiquitous environments. We start the review with a concise background of data stream processing, presenting the building blocks for mining data streams. In a wide range of applications, data streams are required to be processed on small ubiquitous devices like smartphones and sensor devices. Mobile and ubiquitous data mining target these applications with tailored techniques and approaches addressing scarcity of resources and mobility issues. Two categories can be identified for mobile and ubiquitous mining of streaming data: single-node and distributed. This survey will cover both categories. Mining mobile and ubiquitous data require algorithms with the ability to monitor and adapt the working conditions to the available computational resources. We identify the key characteristics of these algorithms and present illustrative applications. Distributed data stream mining in the mobile environment is then discussed, presenting the Pocket Data Mining framework. Mobility of users stimulates the adoption of context-awareness in this area of research. Context-awareness and collaboration are discussed in the Collaborative Data Stream Mining, where agents share knowledge to learn adaptive accurate models.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Toxoplasmosis is widespread zoonosis caused by Toxoplasma gondii,a protozoan that may infect mammals and birds. The aim of the present study was to assess the prevalence of T. gondii in ostriches (Struthio camelus) from commercial breeding facilities in the state of São Paulo, Brazil, in a way to increase the knowledge on the behavior and importance of the parasite in this animal species. A total of 195 serum samples were collected from ostriches from Sorocaba, Campinas, São Carlos, Aracatuba, São Paulo, Vale do Ribeira, Botucatu and sao Jose do Rio Preto, in the state of São Paulo. These samples were analyzed by means of the Modified Agglutination Test (MAT) in order to investigate the occurrence of Toxoplasmagondii antibodies. The test showed that 14.36% of the animals were seropositive to Toxoplasmagondii. Minimum titer was considered to be equal or greater than 1:16, and the greatest dilution observed was 1:16,384. No statistically significant differences were found between males and females. Seronegative animals occurred in only two regions (São Paulo and Sao Jose do Rio Preto). These results point out the importance of further studies on this infection in ostriches, and on management practices that may minimize the risk of toxoplasmosis transmission in these birds which would, in their turn, decrease the risk for the final consumer.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Cryptosporidiosis is a common protozoan disease observed in a wide range of vertebrate hosts, including ruminants. Cattle can be a potential reservoir of Cryptosporidium spp., leading to environmental contamination with oocysts of zoonotic species. The molecular characterization of Cryptosporidium spp. isolated from cattle from the state of So Paulo, Brazil, was accomplished using nested polymerase chain reaction for amplification of fragments of the 18S rRNA gene and the glycoprotein GP60 gene, following sequencing of amplified fragments. Positivity for Cryptosporidium was found in 10.7% (21/196) of the samples. Four species of Cryptosporidium were identified: C. andersoni, C. bovis, C. parvum subtype IIaA15G2R1, and C. ryanae. To the best of our knowledge, this is the first report of infection by C. ryanae and C. parvum IIaA15G2R1 in cattle from Brazil.
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Amphibians are an important component of terrestrial and aquatic freshwater communities worldwide. Especially to the Northern coastal zone of Brazil, the knowledge about amphibian communities is very scarce. We have studied amphibian assemblages along the coastal strip zone of the state of Piaui for two years, covering a distance of ca. 70 km. It was possible to prepare a list of 21 anurans from 6 families (Microhylidae, Hylidae, Leptodactylidae, Cycloramphidae, Leiuperidae, and Bufonidae). All species are common and widely distributed in Brazilian territory, mainly on the Caatinga biome. The results are important to amplify the knowledge on the biodiversity found at the coastal zone of the state of Piaui.
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Includes bibliography
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In this study we report on two new records of the blindsnake Typhlops brongersmianus for the municipality of Bauru, midwestern region of the state of São Paulo, Brazil. These records expand the geographic distribution currently known for this species in the state and contribute to the knowledge of snakes in southeastern Brazil. © 2011 Check List and Authors.
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Although the natural reservoirs of the avian influenza (AI) virus have been extensively studied in many countries, there is a clear lack of information on this subject in South America, particularly in Brazil. The objective of this study was to conduct a serological survey for H5, H7 and H9 antibodies to AI-subtype viruses in wild birds in the state of São Paulo, Brazil. Serum samples were tested using the hemagglutination-inhibition assay. Out of the 31 wild birds sampled between January and December of 2006, seven (22.58%), were seropositive for H5, H7 and H9; four (12.90%) were seropositive for H5 and H7; 13 (41.94%), were seropositive only for H7; three (9.7%), were seropositive only for H9; and four (12.90%) were negative for all three hemagglutinin subtypes. These results indicate that AI viruses belonging to H5, H7 and H9 subtypes circulate among wild birds in the state of São Paulo in the form of either concurrent or consecutive infections. This study contributes to the knowledge of AI epidemiology in Brazil, and stresses the need of further detailed and long-term epidemiological and ecological investigation to determine the current status of this virus.
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Neste artigo, o esforço de investigação ornitológica no estado de Roraima será investigado utilizando abordagens de análises de lacunas. Basicamente, apresentaremos uma síntese sobre todo o esforço ornitológico feito até o momento em Roraima, visando responder as seguintes questões: (a) quais os locais bem amostrados para aves? (b) quais são as lacunas geográficas de investigação? (c) em que estágio de descobertas está o inventário das espécies de aves em Roraima? (d) quais são os macro-hábitats prioritários para investigação? (e) quais os tipos de vegetação bem investigados e quais os que podem ser classificados como prioritários para investigação? Como resultados, detectamos Oitenta e duas localidades com algum tipo de informação ornitológica. Dentre essas, a Estação Ecológica de Maracá (442 sp), seguido pelo Parque Nacional do Viruá (420 sp), Colônia do Apiaú (320 sp), Mucajaí (267 sp), e Pacaráima (212 sp), são as cinco localidades com maior grau de conhecimento ornitológico dentro do estado. Nos últimos 20 anos apenas duas localidades ornitológicas em Roraima podem ser acrescidas à lista de sítios bem estudados de acordo com o critério de pelo menos 100 espécies registradas (peles, gravações de voz e observações visuais): Parque Nacional do Viruá e a Fazenda Paraense. Cinco áreas são aqui apontadas como lacunas de amostragem da avifauna de Roraima e devem receber prioridade para novos inventários e estudos sobre a avifauna dessa região, são elas: Noroeste do estado, nas áreas junto à fronteira com a Venezuela e divisa com o Estado do Amazonas; Baixo Rio Branco, desde a cidade de Caracaraí à sua foz; Florestas de terra firme no sudeste do Estado; As savanas do nordeste junto à fronteira com a Guiana e as regiões de floresta montana e os tepuis.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Amphibian conservation depends on knowledge about species composition and distribution. This emphasizes the need for inventories, especially in poorly sampled areas. This is the case of Southern grasslands (Campos Sulinos) associated with Araucaria forest in the state of Paraná, southern Brazil. We sampled amphibians in 105 environments from 2004 to 2013 using transect sampling, active search and surveys at breeding sites. We found 61 anuran species and two caecilians. This is the first comprehensive list of amphibian species inhabiting grasslands in Paraná. This landscape deserves high conservation priority before these natural grasslands vanish.
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In the early vertebrate embryo, cardiac progenitor/precursor cells (CPs) give rise to cardiac structures. Better understanding their biological character is critical to understand the heart development and to apply CPs for the clinical arena. However, our knowledge remains incomplete. With the use of single-cell expression profiling, we have now revealed rapid and dynamic changes in gene expression profiles of the embryonic CPs during the early phase after their segregation from the cardiac mesoderm. Progressively, the nascent mesodermal gene Mesp1 terminated, and Nkx2-5+/Tbx5+ population rapidly replaced the Tbx5low+ population as the expression of the cardiac genes Tbx5 and Nkx2-5 increased. At the Early Headfold stage, Tbx5-expressing CPs gradually showed a unique molecular signature with signs of cardiomyocyte differentiation. Lineage-tracing revealed a developmentally distinct characteristic of this population. They underwent progressive differentiation only towards the cardiomyocyte lineage corresponding to the first heart field rather than being maintained as a progenitor pool. More importantly, Tbx5 likely plays an important role in a transcriptional network to regulate the distinct character of the FHF via a positive feedback loop to activate the robust expression of Tbx5 in CPs. These data expands our knowledge on the behavior of CPs during the early phase of cardiac development, subsequently providing a platform for further study.
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The article aims to analyze the process of knowledge creation in Brazilian technology-based companies, using as a background the driving and restrictive factors found in this process. As the pillars of discussion, four main modes of knowledge conversion were used, according to the Japanese model: socialization, externalization, combination and internalization. The comparative case method through qualitative research was carried out in nine technology-based enterprises that had been incubated or have recently passed through the stage of incubation (so-called graduated companies) in the Technology Park of Sao Carlos, state of Sao Paulo, Brazil. Among the main results, the combination of knowledge was identified as more conscious and structured in graduated companies, in relation to incubated companies. In contrast, it was noted that incubated companies have an environment with greater opportunities for socialization, internalization and externalization of knowledge.