1,720,979 research outputs found
Conservação da pecuária crioula nos Estados Unidos: desafios e soluções
No full textConservation of criollo breeds in the USA provides for the survival of unique genetic resources that remain productive in challenging environments. Conservation is difficult because most criollo breeds are local and have no formal organization of breeders. Successful conservation has depended on establishing accurate breed definitions and investigations of phenotype, history, and genetics. Organization of breeders and of breeding has been essential for the final success of conservation efforts. Each specific breed has met its own unique challenges. Among cattle breeds, Texas Longhorns needed an accurate breed definition as well as genetic investigations, whereas Florida Crackers needed organization. Spanish goats required definition, organization, and research into their productive potential. This has led to the Spanish goat now being secure as a popular choice for extensive production of goat meat. Navajo Churro sheep are maintained by ongoing phenotypic evaluation at each generation and careful attention to the frequency of phenotypic characteristics within the population. The other criollo sheep breeds in the USA (Louisiana, Gulf Coast, and Florida) have benefitted from genetic studies that demonstrate differences among the breeds and guide conservation of each of these related types in isolation one from the others. The organization of criollo swine has lagged behind the others, with the Duroc standing out as an exception that has become one of the main breeds in commercial hog production.La conservación de las razas ganaderas criollas en los EE.UU. ha contribuído a la sobrevivencia de recursos zoogenéticos únicos que tienen buena producción en ambientes duros. La conservación es difícil porque la mayoría de estas razas son locales y no tienen una organización formal de los criadores. El éxito depende en una definición fija para la raza, e investigaciones del fenotipo, la historia, y la genética. Organizar a los criadores y la crianza ha sido esencial en el éxito final de las razas. Cada raza enfrente sus propios desafíos. Entre las razas bovinas el Texas Longhorn necesitó una definición preciso tanto investigaciones de la genética para asegurar niveles bajos de la introgresión de otras razas. La raza bovina Florida Cracker necesitó una organización de los criadores. La raza caprina Spanish requirió definición, organización, e investigaciones de las características productivas. Esta raza ya está seguro por su papel en sistemas productivos en situaciones extensivas. La raza ovina Navajo Churro se mantiene por una evalución fenotípica para todos los animales de toda generaciones, y también por mantener la frecuencia de varias características fenotípicas. Las otras razas criollas ovinas (Louisiana, Gulf Coast, and Florida) fueron documentados como tres poblaciones por investigaciones genéticas que demostraron diferencias entre ellas. Las investigaciones ayudan in la conservación de las tres razas una aislada a las otras. La organización de los porcinos criollos no es muy avanzada. La raza Duroc es un tipo de criollo que ha llegado a tener un papel importante en la producción porcina comercial.A conservação das raças criollas nos EUA proporciona a sobrevivência de recursos genéticos únicos que permanecem produtivos em ambientes desafiadores. A conservação é difícil porque a maioria das raças criollas são locais e não têm uma organização formal de criadores. A conservação bem-sucedida depende do estabelecimento de definições precisas de raça e investigações de fenótipo, história e genética. A organização dos criadores e da criação tem sido essencial para o sucesso final dos esforços de conservação. Cada raça específica encontrou seus próprios desafios únicos. Entre as raças de gado, o Texas Longhorns precisava de uma definição precisa da raça, bem como de investigações genéticas, enquanto o Florida Crackers precisava de organização. As cabras espanholas exigiam definição, organização e pesquisa sobre seu potencial produtivo. Isso fez com que a cabra espanhola agora se tornasse uma escolha popular para a produção extensiva de carne de cabra. Os ovinos Navajo Churro são mantidos por avaliação fenotípica contínua em cada geração e atenção cuidadosa à frequência das características fenotípicas na população. As outras raças de ovinos crioulos nos EUA (Louisiana, Gulf Coast e Flórida) se beneficiaram de estudos genéticos que demonstram diferenças entre as raças e orientam a conservação de cada um desses tipos relacionados isoladamente uns dos outros. A organização da suinocultura crioula ficou atrás das demais, destacando-se o Duroc como uma exceção que se tornou uma das principais raças na produção comercial de suínos
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
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
Role of CD44 in Immune Functions and Endothelial Cell Injury
No full textIn addition to the antigen-specific receptors, the T and B cells also express a variety of adhesion molecules, which are known to participate in cell-cell interaction, migration, homing and signal transduction. CD44 is a widely distributed cell surface glycoprotein whose principal ligand has been identified as hyaluronic acid (HA), a major component of the extracellular matrix. In the current study, we investigated whether HA or mAbs against CD44 would induce a proliferative response in mouse lymphocytes. Spleen cells from normal and nude but not severe combined immunodeficient mice, exhibited strong proliferative responsiveness to stimulation with soluble HA or anti-CD44 mAbs. Furthermore, purified B cells but not T cells were found to respond to HA. These data demonstrated that interaction between HA and CD44 can regulate murine B cell effector functions and that such interactions may play a critical role during normal or autoimmune responsiveness of B cells.
Endothelial cell injury resulting in vascular leak syndrome (VLS) is one of the most widely noted phenomenons in a variety of clinical diseases, however, the underlying reason for which remains unclear. We used interleukin-2 induced VLS as a model to investigate the role of cytolytic lymphocytes in the direct cytotoxicity of endothelial cells. BL/6 wild-type mice developed significant VLS in the lungs, liver and spleen following IL-2 administration. Interestingly, perforin-knockout mice exhibited marked decrease in VLS in all three organs tested. Also, FasL-defective (gld) mice and Fas-deficient (lpr) mice exhibited decreased VLS in the liver and spleen, but not in the lungs. These results demonstrated for the first time that perforin and FasL may actively participate in endothelial cell injury and induction of VLS in a variety of organs.
Inasmuch as, CD44 also plays a major role in the lymphocyte adhesion to the endothelial cells, we used CD44-knockout mice and observed that such mice exhibited markedly diminished VLS following IL-2-treatment. Our data also suggested that blocking CD44 helps in reducing the IL-2-induced VLS and therefore such an approach may serve as a useful tool to prevent endothelial cell damage seen in a variety of clinical disorders.Ph. D
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
Genetic variation of susceptibility to fescue toxicosis in cattle
No full textFifteen calves of two sires were fed endophyte infected (E + ) fescue seed to quantify differences in susceptibility to fescue toxicosis among sire groups. One of the sires, a Polled Hereford, had a commercial reputation of producing calves with less severe symptoms of tall fescue toxicosis than their contemporaries. The control sire, also a Polled Hereford, had unknown merit with regard to offspring susceptibility to fescue toxicosis. The study was divided into five phases, two in which endophyte-infected fescue seed was included in the diet (phases two and four) and three in which fescue seed was not in the diet (phases one, three, and five). All calves were treated similarly and given the same opportunities for water, shade and socialization. Susceptibility to fescue toxicosis was measured by appetite (amount of feed consumed per day per unit of metabolic body weight), serum prolactin, cholesterol, and alkaline phosphatase concentrations, ability to maintain homeotherny (afternoon minus morning rectal temperature), ability to dissipate core body heat (afternoon minus morning surface temperature), and heat-transfer inefficiency (afternoon rectal minus afternoon surface temperatures). Appetite was decreased by the E + fescue seed, but the sire groups did not differ in their response to or recovery from E + fescue seed. The E + fescue seed caused prolactin to decrease (P < .0001) but the sire groups did not differ in their responses to addition or withdrawal of E + fescue seed from the diet. Cholesterol levels were lower overall (P < .001) when the E+ fescue seed was fed, and the sire groups recovered from the fescue toxicity at different rates (P < .001). Alkaline phosphatase concentrations were lower during the phases when E + fescue seed was fed; calves from the control sire were less resistant to the E + fescue seed effects than the Missouri calves (P < .0001). Ability to maintain homeothermy was reduced by the E + fescue seed, but the reduction did not differ between sire groups. Surface temperature changes and heat-transfer inefficiencies were not indicative of fescue toxicosis in this study. It was concluded that serum cholesterol and serum alkaline phosphatase concentrations may be accurate indicators of differences among paternal half sib groups of cattle in susceptibility to fescue toxicosis.Master of Scienc
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