1,720,971 research outputs found
Eficiencia y partición energética de dos líneas genéticas Holando bajo pastoreo
Full text linkEl objetivo del trabajo fue evaluar el efecto de dos líneas genéticas Holando
(Holando neozelandés vs. Holando norteamericano; HNZ vs. HNA) sobre la partición
de la energía metabolizable consumida (CEM) entre la producción de calor (PC) y la
energía retenida (ER) de vacas lecheras en pastoreo. Se realizaron dos experimentos;
en el experimento 1, las vacas fueron alimentadas mediante pastoreo y suplementadas
con 1/3 de la dieta con concentrado mientras que en el experimento 2 las vacas se
alimentaron exclusivamente con pastura mediante pastoreo. La PC se midió utilizando
la técnica del pulso de O₂ y la ER en leche se calculó en base a la producción de leche
y su composición mientras que la ER en tejido se estimó a través de los cambios en
peso vivo (PV) y condición corporal. En el experimento 1, las vacas HNA presentaron
mayor PC y PC residual que se asoció con mayores requerimientos de energía
metabolizable de mantenimiento (EMm) que las vacas HNZ. Sin embargo, a pesar de
las diferencias en PC, la retención de la energía metabolizable consumida (ER/CEM)
no fue afectada por la línea genética Holando. Por otro lado, en el experimento 2, las
vacas HNZ presentaron un mayor consumo de pastura en relación a su PV que
determinó un mayor CEM (kJ/kgPV0,75/d) que en las vacas HNA. El mayor CEM
permitió una mayor dilución de los requerimientos de mantenimiento en las vacas
HNZ resultando una mayor eficiencia alimenticia y ER/CEM. Los resultados de estos
experimentos indicarían que la EMm (kJ/kgPV0,75/d) fue 10% mayor en las vacas HNA
que HNZ, lo que probablemente pueda asociarse a un mayor tamaño relativo de
órganos internos y/o una mayor proporción de proteína en su composición corporal
como consecuencia de su selección genética. Se puede concluir que las vacas HNZ
tendrían una mayor partición energética hacia la producción de leche que las vacas
HNA cuando son alimentadas exclusivamente bajo pastoreo sin suplementación,
mientras que estas diferencias no se expresarían bajo un sistema pastoril con alta
suplementación con concentrado que permita levantar, al menos parcialmente, las
restricciones en el CEM que impone el pastoreo en las vacas de alta producción
(HNA)
Mantenimiento : ¿el componente subvalorado de la eficiencia energética de vacas lecheras en pastoreo?
No full textTribunal: Ku Vera, Juan Carlos; Colombatto, Darío; Beretta, Virginia.Las vacas lecheras en pastoreo presentan un mayor costo energético de mantenimiento que las vacas alimentadas en confinamiento como consecuencia de una mayor actividad física vinculada a la caminata y cosecha del alimento. Sin embargo, con base en la literatura actual, no existe una cuantificación de estos componentes en vacas lecheras. El objetivo principal de esta tesis fue cuantificar el costo energético de pastoreo y caminata en vacas lecheras. Para esto, se validó la técnica del pulso de oxígeno-frecuencia cardíaca (O₂P-HR) en cámaras respirométricas para ser utilizada en la medición de la producción de calor (HP) de vacas lecheras en condiciones reales de producción. Luego, a través de mediciones de HP realizadas con la técnica O₂P-HR y sincronizadas con registros de actividad de las vacas, se estimó el costo energético de pastoreo y caminata. Los resultados de este trabajo demuestran que el costo energético de pastoreo en vacas lecheras es de 7,24 kJ/kg⁰,⁷⁵ por hora y que por unidad de tiempo no es diferente del costo energético de comer una dieta total mezclada en un comedero y que, por lo tanto, la menor tasa de consumo en los animales en pastoreo y el mayor tiempo que estos destinan a consumir es lo que incrementa el costo energético de alimentación diario o por unidad de alimento consumido. Por otro lado, las vacas requirieron 1,5 kJ/kg por kilómetro caminado para trasladarse desde la pastura hacia la sala de ordeñe y viceversa. En un sistema de producción de leche promedio de nuestro país, estos resultados representan que alimentar las vacas en un sistema pastoril costaría entre 2 a 3 litros de leche/vaca por día en comparación a si se alimentaran en confinamiento, indicando que la menor producción de leche y eficiencia de conversión de los sistemas de producción de leche pastoriles en comparación a los sistemas confinados se debe principalmente al menor consumo de alimento y, en menor medida, al aumento en los costos energéticos de mantenimiento asociados al pastoreo y la caminata
‘The Churchillian Paradigm and the “Other British Isles”: An Examination of Second World War Remembrance in Man, Orkney, and Jersey’
No full textThis dissertation studies Second World War ‘sites of memory’ in the islands of Jersey, Orkney and the Isle of Man, to determine if each island celebrates the war’s events as Britain does, or if they have charted their own mnemonic course. It builds on the work of Angus Calder, Malcolm Smith, and Mark Connelly, who have explored how popular conception of the Second World War in Britain has been structured around a certain set of commemorative motifs, most of which centre on Winston Churchill and the events of 1940. The British war narrative is now commonly referred to as the ‘Churchillian paradigm’ or ‘finest-hour myth’, and continues to be the driving force in commemoration and memorialization on the British mainland. The three islands in this study are culturally and historically distinct from Britain, and each has strong notions of its own ‘island identity’. Each also possesses a tangential and divisive domestic experience of war, one which is often minimized in the iconography of the Churchillian paradigm. Jersey was occupied by Nazi Germany from 1940 to 1945, Orkney was home to several thousand Italian POWs who built important infrastructure in the island, and the Isle of Man was home to 14,000 German, Finnish, Japanese, and Italian internees in what one critic has called ‘a bespattered page’ in the nation’s history. By examining ‘sites of memory’— museums, heritage sites, commemorations, celebrations, philately, and use of public space—this dissertation shows that each island simultaneously accepts and rejects elements of the finest-hour myth in their collective memory. Each island displays its unique (though often quite negative) heritage in order to differentiate itself from Britain, while at the same time allowing them, at certain events, to participate in celebration of Britain’s ‘greatest victory’. In this way, islands’ use ‘Britishness’ pragmatically, by basking in traditionally ‘British’ commemorative tropes, while at the same time deepening their own cultural and historical sovereignty
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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