1,721,766 research outputs found
Characterization of the resistance to the anorectic and endocrine effects of leptin in obesity-prone and obesity-resistant rats fed a high fat diet
No full textLeptin produced by adipocytes controls body weight by
restraining food intake and enhancing energy expenditure
at the hypothalamic level. The diet-induced increase in fat
mass is associated with the presence of elevated circulating
leptin levels, suggesting the development of resistance to
its anorectic effect. Rats, like humans, show different
susceptibility to diet-induced obesity. The aim of the
present study was to compare the degree of leptin resistance
in obesity-prone (OP) vs obesity-resistant (OR) rats
on a moderate high-fat (HF) diet and to establish if the
effects of leptin on hypothalamo–pituitary endocrine functions
were preserved. Starting from 6 weeks after birth,
male Sprague–Dawley rats were fed on either a commercial
HF diet (fat content: 20% of total calorie intake) or a
standard pellet chow (CONT diet, fat content: 3%). After
12 weeks of diet, rats fed on HF diet were significantly
heavier than rats fed on CONT diet. Animals fed on HF
diet were ranked according to body weight; the two tails
of the distribution were called OP and OR rats respectively.
A polyethylene cannula was implanted into the
right ventricle of rats 1 week before central leptin administration.
After 12 weeks of HF feeding, both OR and OP
rats were resistant to central leptin administration (10 μg,
i.c.v.) (24 h calorie intake as a percent of vehicle-treated
rats: CONT rats, 62 [50; 78]; OR, 93 [66; 118]; OP, 90
[70; 120] as medians and 95% confidence intervals (CIs) of
six rats for each group). Conversely, after 32 weeks of diet
both OR and OP rats were partially responsive to 10 μg
leptin i.c.v. as compared with CONT rats (24 h calorie
intake as a percent of vehicle-treated rats: CONT rats, 60
[50; 67]; OR, 65 [50; 80]; OP, 80 [60; 98] as medians and
95% CIs of six rats for each group); the decrease of food
intake following 200 μg leptin i.p. administration was
similar in all the three groups (calorie intake as a percent of
vehicle-treated rats: 86 [80; 92] as median and 95% CI).
The long-term intake of HF diet caused hyperleptinemia,
hyperinsulinemia and higher plasma glucose levels in OP
rats as compared with CONT rats. Plasma thyroxine (T4)
was lower in all the rats fed the HF diet as compared with
CONT. i.c.v. administration of leptin after 32 weeks of
diet restored normal insulin levels in OP rats. Moreover,
leptin increased plasma T4 concentration and strongly
enhanced GH mRNA expression in the pituitary of OP as
well as OR rats (18010% vs vehicle-treated rats). In
conclusion, long-term intake of HF diet induced a partial
central resistance to the anorectic effect of leptin in both
lean and fat animals; the neuroendocrine effects of leptin
on T4 and GH were preserved
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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