1,721,033 research outputs found
Changes in the pause in muscle spindle discharge during a sequence of twitches. Expl. Neurol. 60: 201-212.
No full textA study was made of the change in duration of the pauses in discharge from spindle afferents occurring during a series of isometric twitches of the cat's triceps surae muscle. These were induced by stimulation of the muscle nerve at frequencies of 0.1 to 1.0 Hz. At frequencies of 0.2 Hz and higher, the duration of the pause exhibited by group II and tonic and phasic group Ia afferents decreased progressively until stabilizing within 5 to 15 s. The time course of this change was largely independent of the frequency of stimulation, but the eventual duration in the steady state was strongly dependent on the frequency, being shorter at higher rates. At a given frequency, the pause was shorter at longer muscle lengths. The decrease in pause duration was not accompanied by a parallel change in duration or amplitude of the muscle tension responses, indicating that it arose from some alteration intrinsic to the spindle organ. We suggest that the progressive change in sensory discharge could serve the initial reinforcement of repetitive movements
Variazioni plasmatiche del Glucosio, del ß-OH-idrossibutirrato, dei NEFA e dell'Urea in pecore sarde a fine gravidanza sottoposte a diversi livelli di esercizio fisico.
No full textLipid Metabolism in the rumen: new insights on lipolysis and biohydrogenation with an emphasis on the role of endogenous plant factors.
No full textDiet composition is the major factor influencing the fatty acid composition of meat and milk from ruminants because the fatty acids (FA) which reach the duodenum are, at least in part, of dietary origin as well as the result of rumen microbial biohydrogenation (BH) of dietary lipids. In this review, effects of synthesis of conjugated linoleic (CLA) and linolenic (CLNA) acid isomers in the rumen, effects of the lipids in herbage, and plant endogenous factors on synthesis of nutraceutical fatty acids are discussed. Discovery of beneficial FA in ruminant products, such as CLA and other omega-3 FA, stimulated many studies in the last 20 years, including those on the roles of minor FA intermediates on rumen BH and mammary gland Metabolism. Much of this research was targeted at identifying the intermediates formed during BH as well as the rumen microbial ecology involved in these processes. However, shifting the research to feedstuff endogenous factors which influence lipolysis (LP) and losses of polyunsaturated FA in the rumen may be of interest in identifying nutritional strategies to manipulate FA profiles in ruminant products. The presence of FA with healthful properties in milk or meat from ruminants can be enhanced by inclusion of fresh forages in their diet. Hence, there is increasing interest in the crucial role of endogenous LP, plant secondary metabolites (PSM) and polyphenol oxidase (PPO) on ruminal BH. To better understand the pathways through which PSM or PPO impact FA metabolism, characterization of lipids in fresh forages suggests the important role of the diet matrix on the ruminal fate of lipids. A critical discussion of the role of odd chain branched FA (OBCFA) is also reported, including potential impacts on rumen microbial metabolism. Finally, new insights into lipid metabolism from in vitro techniques are discussed
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
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