1,721,069 research outputs found
Nutritional and anti-nutritional values of multipurpose trees used in agroforestry systems
No full textMultipurpose trees (MPTs) improve the utilization of poor quality roughages. In addition to their feed value, MPTs contribute to the environment, e.g. by conserving soil. However, some MPTs contain anti-nutritional factors which reduce their nutritive value. Trials in which gas production and rumen degradation rates were studied indicated that MPTs increased the rates of degradation of fibrous feeds, their rate of passage and the efficiency of microbial protein supply. The effects of extracts of several MPTs on pure cultures of Fibrobacter succinogenes, Ruminococcus flavefaciens and R. albus were Reported. Acacia angustissima suppressed the growth of Ruminococcus and slowed the growth of other bacteria. Dry matter yields were significantly increased when leucaena or gliricidia were intercropped with maize/cassava or napier grass in agro-forestry systems. It was concluded that the improved milk production resulting from such systems has many social benefits for the smallholder and his family
PRODUCTION SYSTEMS RESEARCH: SOME METHODOLOGICAL CONSIDERATIONS
Get PDFThe major limitation of traditional station-based research is its failure to account for the multiplicity of socioeconomic and ecosystemic variables that determine the success or failure of the farmer. Production systems research however focuses on the farm and the farmer using station-based research to complement the farm-based work. This paper deals with the issues involved in the ex-ante analysis of the factors affecting farm profitability. These considerations result in the identification of research opportunities vis-a-vis cost of research and the definition of the domain of recommendations. TIle instruments used in this exercise are identified and briefly discussed. The ex-post analysis of the results of the research efforts using economic, evaluation criteria lead to the selection of alternatives or modified systems which may improve the farm. Some of these economic criteria are discussed. tile paper recognises the tremendous virtues of production systems research but notes the factors (political, social, economic) which influence the adoption of alternatives. ----- La mayor Iimitacidn de la investigacion tradicional-en at sede (estaci6n experimental) - es la falta de considerar la multiplicidad de variables soeio-economicas y ecosistemtiticas, las cuales determinan el €xito 0 el fracaso del agricultor. Sin embargo, la investlgacidn de sistemas de la producci6n, concentra sus miras en la finca y en el agricultor utilizando, investigacion-en la sedepara complementar el trabajo en la finca. Este inforrne trata de puntos involucrados en el anlllisis "ex-ante" de los factores que afectan las ganancias de la finca. Estas consideraciones resultan en la identificacion de oportunidades de invcstigacion en 10 referente a, el cos to de la investigacidn y la definici6n del "dominic de recornendaciones." Las tecnicas y metodos utilizados en este ejercicio so identificados y discutidos brevemente. EI analisis "ex-post" de los resultados de la investigacidn, utilizando un criterio economico de evaluacion, facilita la selecci6n de alternativas 0 sistemas modificados, 10 cual mejora la finca. Algunos de estos criterios de la investigacion de sistemas de producci6n, pero apunta los factores (politicos, sociales, economicos) que influyen la adopcion de alternativas
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
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