1,721,044 research outputs found
IGF2 and IGF1R mRNAs Are Detectable in Human Spermatozoa
No full textOligozoospermia is highly prevalent worldwide. Studies have reported a lower methylation rate in the H19 differentially methylated region at the sperm level in oligozoospermic patients than in controls. IGF2/H19 are the best-known pair of imprinted genes. However, no studies have yet evaluated whether they are transcribed in human sperm. To assess whether IGF2 and IGF1R mRNAs are present in human sperm and if their levels are correlated with sperm concentration and total sperm count
Gene-environment interaction in functional hypothalamic amenorrhea
No full textFunctional hypothalamic amenorrhea (FHA) is a common cause of amenorrhea and chronic anovulation in adolescent girls and young women, diagnosed after excluding other organic causes. It is commonly associated with calorie restriction, excessive physical exercise, and psychosocial stress. These stressors alter the pulsatile secretion of gonadotropin-releasing hormone, leading to a chronic condition of hypoestrogenism and significant health consequences. Recent evidence has highlighted a genetic predisposition to FHA that could explain interindividual variability in stress response. Indeed, not all women experience FHA in response to stress. Rare variants in genes associated with idiopathic hypogonadotropic hypogonadism have been identified in women with FHA, suggesting that these mutations may contribute to an increased susceptibility of women to the trigger of stress exposure. FHA appears today as a complex disease resulting from the combination of genetic predisposition, environmental factors, and epigenetic changes. Furthermore, the genetic background of FHA allows for the hypothesis of a male counterpart. Despite the paucity of data, preliminary findings indicate that an equivalent condition of FHA exists in men, warranting further investigation. This narrative review aims to summarize the recent genetic evidence contributing to the pathophysiology of FHA and to raise awareness on a possible male counterpart
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
Late-onset hypogonadism: beyond testosterone
No full textLate-onset hypogonadism is defined as a combination of low testosterone (T) levels and typical symptoms and signs. A major area of uncertainty is whether T concentrations are always really sufficient to fully reflect Leydig cell (dys)function. Mild testicular alteration could be diagnosed only by additional biochemical markers, such as luteinizing hormone (LH) and 25-hydroxyvitamin D levels. These markers help in identifying the so-called "subclinical" hypogonadism (normal T, high LH levels). Patients with hypogonadism have frequently low levels of 25-hydroxyvitamin D due to impairment of the hydroxylating enzyme CYP2R1 in the testis. However, no data have been published dealing with the best treatment option (cholecalciferol - the Vitamin D precursor, or calcidiol - 25-hydroxylated form of Vitamin D) in these patients. We studied 66 patients with classic hypogonadism (total T [TT] <12 nmol l-1 , LH ≥ 8 IU l-1 ) (n = 26) and subclinical hypogonadism (TT ≥ 12 nmol l-1 , LH ≥ 8 IU l-1 ) (n = 40) and low 25-hydroxyvitamin D (<50 nmol l-1 ). Subjects received cholecalciferol (5000 IU per week) (n = 20) or calcidiol (4000 IU per week) (n = 46), and 25-hydroxyvitamin D and parathyroid hormone (PTH) were evaluated after 3 months of therapy. Supplementation with calcidiol significantly increased 25-hydroxyvitamin D and significantly decreased PTH levels in both groups of men with hypogonadism (primary, n = 16 and subclinical, n = 30), whereas supplementation with cholecalciferol did not modify their levels. This study shows for the first time that the administration of the 25-hydroxylated form of Vitamin D (calcidiol), and not the administration of the precursor cholecalciferol, restores 25-hydroxyvitamin D levels in subjects with hypogonadism
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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