1,721,219 research outputs found
Symposium review : Macronutrient metabolism in the growing calf
Full text linkRecent interest in increasing rates of body weight gain in heifer calves before weaning is based on the promise of an increase in milk production during first lactation. This increase is usually realized by increasing milk or milk replacer intake, delaying the onset of rumen development. Simultaneously feeding liquids and solid feeds brings about new challenges. Macronutrient metabolism in growing calves is reviewed, combining literature from heifer and veal calves with the objective to provide insights useful for developing novel feeding strategies. Growing calves are not efficiently retaining digested N when compared with other growing species. Energy and protein appear to be simultaneously limiting growth. With the possible exception of very young calves, low responses to incremental intakes of AA indicate that the limiting AA rarely explains the low efficiency of N utilization. Nonetheless, there are indications that disproportionate oxidation of AA as a result of AA imbalance may occur, notably in splanchnic tissues. Long-chain fatty acids, absorbed from the milk or calf milk replacer (CMR) are preferentially deposited as body fat, but this strongly depends on the need for ATP, fueled by the oxidation of carbohydrates. Hence, fatty acid oxidation typically decreases with an increased feeding level. Insulin sensitivity in calves is quite high at birth, but decreases independent of feeding strategy in early age to very low levels when compared with other species. Even though changes in insulin sensitivity may be provoked by early life nutrition, these effects are small and rather transient. In heavy calves, insulin sensitivity is invariably low. Large effects of dietary treatments on postprandial glucose and insulin responses, as often observed, are unlikely to be caused by differences in insulin sensitivity. Unlike in pigs, de novo fatty acid synthesis is not a significant route of disposal of glucose absorbed from the intestinal tract. Instead, high lactate fluxes in milk-fed calves suggest this may be an important route of disposal. When combining the feeding of milk or CMR with solid feeds, estimation of the contribution of the individual ration components is difficult, and interactions inside the gastrointestinal tract complicate the estimation of their feeding value. There are indications in veal calves that use of nutrients absorbed from a CMR is not dependent on the level of intake of solid feeds.</p
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
Oligosaccharides to suppress respiratory infections: A translational approach
No full textThe studies described in this thesis have investigated the anti-inflammatory effects and possible mechanisms of non-digestible oligosaccharides (NDOs), including galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS), in respiratory infections in calves naturally exposed to respiratory pathogens, with a possible translation to human respiratory infections. An in vivo model in calves and in vitro models in primary bronchial epithelial cells obtained from calves and human lung epithelial cells were used to investigate the potential effects and mechanisms of GOS and FOS. Anti-inflammatory effects of GOS and FOS observed in vitro were compared with the effects on inflammatory markers in the airway and blood of calves fed with these NDOs. The main mechanisms related to anti-inflammatory effects of GOS and FOS derived from the present in vitro studies include 1) the anti-bacterial effect of GOS at high concentrations on respiratory pathogens (e.g., Mannheimia haemolytica and Mycoplasma pneumoniae), 2) possible interference with Toll-like receptor 4 proinflammatory signaling and inhibition of oxidative stress by GOS at low concentrations, and 3) possible interference with Toll-like receptor 5 proinflammatory signaling and protection of airway epithelial barrier function by FOS. Due to these mechanisms, (oral or intranasal) GOS and FOS (partly) relieved lung infections and suppressed airway and systemic inflammation in calves. Finally, these results might contribute to reducing the future use of antibiotics in livestock species and humans and need to be incorporated into the evolving knowledge of microbiota-dependent or -independent effects of NDOs
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
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