1,721,929 research outputs found
Detecção de Listeria monocytogenes em produtos a base de pescado e comparação de métodos PCR em tempo real e ISO11290-1
Get PDFDissertação (mestrrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Ciência dos Alimentos, Florianópolis, 2015.O pescado é um alimento de extrema importância na dieta dos seres humanos, pois possui um alto valor nutricional, contribuindo na preservação da saúde humana. Porém, esses alimentos, principalmente os produtos a base de pescados prontos ou pré-prontos para o consumo, quando indevidamente preparados, podem se tornar veículo de transmissão de perigosos agentes infecciosos, como Listeria monocytogenes. Esse micro-organismo, que é natural do ambiente marinho, é considerado como agente etiológico de enfermidades alimentares representa um risco potencial para a saúde dos consumidores, principalmente mulheres gestantes, pessoas idosas e imunodeprimidos. As análises convencionais para detecção de L. monocytogenes nestes produtos, como a ISO 11290-1, apesar de ainda muito utilizadas no Brasil, são técnicas laboriosas, demoradas e de sensibilidade reduzida. Os métodos moleculares atuais, como o PCR em tempo real, por exemplo, são extremamente sensíveis, rápidos e eficientes para a detecção de patógenos alimentares. Com base nisso, esse estudo teve como objetivo detectar a presença de L. monocytogenes em amostras de produto a base de pescado através de dois protocolos distintos (utilizando um kit comercial e um protocolo in house) de uma técnica molecular: o PCR em tempo real. Os resultados foram comparados aos obtidos com a técnica convencional ISO 11290-1. Foram analisadas, ao todo, noventa amostras de produtos a base de pescados vendidos nos supermercados do litoral de Santa Catarina. As amostras incluíram nove tipos de produtos de pescado, sendo eles: 10 amostras de pizza de atum, 10 amostras de kani, 10 amostras de bolinho de bacalhau, 10 amostras de bolinho de peixe, 10 amostras de hambúrguer de peixe, 10 amostras de filé de peixe, 10 amostras de marisco cozido, 10 amostras de nuggets de merluza e 10 amostras de nuggets kids. Foi detectada a presença de L. monocytogenes em oito amostras (8,88%) pelo protocolo PCR em tempo real in house, sete amostras (7,77%) pelo protocolo PCR em tempo real com kit comercial e seis amostras (6,66%) pela técnica ISO 11290-1. Os produtos que tiveram amostras positivas foram: pizza de atum, bolinho de bacalhau, bolinho de peixe e filé de peixe. Os resultados demonstraram uma elevada incidência de L. monocytogenes nos produtos a base de pescados pesquisados, além de indicar uma maior sensibilidade da metodologia molecular comparada á metodologia convencional, sendo que o protocolo in house da técnica de PCR em tempo real foi o mais sensível, mesmo não apresentando diferença significativa estatisticamente.Abstract : Seafood are an extremely important food in the human diet, due to its high nutritional value, contributing to the preservation of human health. However, these foods, especially ready to eat (RTE) fish-based products or pre- prepared could become dangerous vehicle for infectious agents such as Listeria monocytogenes (L. monocytogenes), when incorrectly prepared. This micro-organism is considered as the etiological agent of food illnesses with hight potential risk to the consumers health, especially pregnant women, elderly and immunocompromised. Conventional methods for L. monocytogenes in these products, such as ISO 11290-1, still widely used in Brazil, has laborious, hight time consuming and reduced sensitivity. Current molecular techniques, such as real-time PCR, for example, are extremely sensitive, fast and effective for the detection of foodborne pathogens. On that basis, this study aimed to detect the presence of L. monocytogenes in fish-based product sample using two different protocols (application of commercial kit and protocol in house) of a molecular technique: the real-time PCR. The results were compared to those obtained with the conventional technique acoording to ISO 11290-1. There were analyzed ninety samples of the fish-based products sold in supermarkets from the coast of Santa Catarina. The samples included nine types of fish products, which were: ten samples of tuna pizza, ten samples of kani, ten samples of codfish balls, ten samples of fish dumpling, ten samples of fish burger, ten samples of fish fillet, ten samples of baked seafood, ten samples of hake nuggets and ten samples of nuggets kids. L. monocytogenes was detected in eight samples (8.88%) by real-time PCR protocol in house, in seven samples (7.77 %) by real time PCR protocol with a commercial kit and in six samples (6.66 %) by ISO 11290-1 technique. The products which had positive samples were tuna pizza, codfish balls, fish fillet and fish balls. The results showed a high incidence of L. monocytogenes in fish-based products, and indicate an increased sensitivity of PCR analysis compared to conventional methodology, and the protocol in house of the real-time PCR assay technique was the most sensitive, despite not having statistically significant difference
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Comparação de metodologia alternativas para detecção de salmonella sp e listeria monocytogenes em carnes e produtos cárneos
Get PDFTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Ciência dos Alimentos.Com o objetivo de validar metodologias analíticas alternativas para detecção de Salmonella spp e Listeria monocytogenes em amostras de carcaças de frango, carnes suínas cruas e, derivados cárneos processados naturalmente contaminados, foram analisadas 503 amostras para detecção de Salmonella spp e 334 amostras para detecção de L. monocytogenes. Na análise de Salmonela spp em amostras de carnes suínas e carcaças de frango, o método AOAC 993-07 (MSRV Acumedia), apresentou maior sensibilidade, seguido do método PCR BAX System®, do Método AOAC 993-07 (MSRV Oxoid) e, do método de referência ISO 6579. Segundo o teste não paramétrico de McNemar, há diferença significativa na comparação do método AOAC 993-07 (MRSV Acumedia) e o método ISO 6579, entre o método ISO 6579 e o método BAX System®, entre o método AOAC 993-07(MRSV Oxoid) e o BAX System® e entre os métodos AOAC 993-07 entre si. Não houve diferença significativa entre os métodos Bax System® e AOAC 993-07 (MRSV Acumedia), e ISO 6579 versus o método 993-07 (MRSV Oxoid). Para a análise de L. monocytogenes em amostras de carnes cruas e produtos processados o método BAX System® apresentou maior sensibilidade, seguido pelo método ISO 11290-1/A1, USDA/FSIS modificado e ISO modificado. Há diferença significativa entre os métodos ISO 11290-1/A1 e o BAX System®, ISO modificado e o método BAX System®e entre o método USDA/FSIS modificado e o BAX System®; Não há diferença significativa entre os métodos ISO 11290-1/A1 e o método USDA/FSIS modificado, entre o método ISO 11290-1/A1 e o método ISO 11290-1/A1 modificado, e, finalmente, entre os métodos ISO 11290-1/A1 modificado e USDA/FSIS modificado. Avaliou-se também a aplicação do Teste de McNemar para a comparação de proporções em amostras dependentes para verificar a conveniência da substituição de um método convencional por um novo, na identificação da presença de Salmonella spp. Resultado deste estudo mostrou que o Teste de McNemar nem sempre é suficiente para a tomada de decisão final do pesquisador em amostras naturalmente contaminadas e que funções apropriadas das proporções necessitam ser estimadas. Neste sentido, o Poder de Teste de McNemar (1 - erro tipo II) foi aqui também estudado no capitulo 4
Detection of Listeria spp. and Listeria monocytogenes in retail dairy products using the Vitek immunodiagnostic assay system LDUO method and ISO method 11290-1
No full textThis study aims to determine the presence of Listeria monocytogenes, an important infectious agent in humans, and other Listeria spp. in retail dairy products using the Vitek Immunodiagnostic Assay System LDUO (VIDAS LDUO) rapid detection method and ISO method 11290-1 (ISO 11290-1). One hundred dairy products (10 pasteurised milk, 10 kashar cheese, 20 white cheese, 18 mihalic cheese, 12 curd cheese, 20 ice cream, and 10 butter samples), collected randomly from food stores in Bursa, Turkey were analysed using the VIDAS LDUO and ISO 11290-1 methods. The results showed that one dairy sample (1%), a mihalic cheese, was positive for both Listeria spp. and L. monocytogenes. This finding highlights the risk of Listeria contamination of cheese manufactured from raw milk
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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