1,721,028 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Downregulation of miR-410 targeting the cyclin B1 gene plays a role in pituitary gonadotroph tumors
Get PDFMicroRNAs (miRNAs) are small noncoding RNAs that act as posttranscriptional regulators of gene expression, and are frequently altered in human neoplasias. Here, we have analyzed the miRNA expression profile of human gonadotroph adenomas versus normal pituitary tissue using a miRNACHIP microarray. We demonstrate that miRNA-410 is downregulated in gonadotroph adenomas when compared with normal pituitary gland. We validate CCNB1 as target of miRNA-410 since its overexpression reduces CCNB1 at protein and mRNA levels, decreasing cell proliferation. In conclusion, our study suggess that the downregulation of miRNA-410 plays a role in the behavior of gonadotroph tumors
Initial pathology in aggressive pituitary tumours and carcinomas: 2b or not 2b?-that is the question
Get PDFMetabolic health: pathophysiological trajectories and therap
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Clinical characteristics and novel diagnostic tests in patients with arginine vasopressin deficiency (central diabetes insipidus)
Get PDFBackground: Arginine vasopressin (AVP) deficiency (central diabetes insipidus) is a neuroendocrine condition characterised by polyuria and polydipsia. The diagnostic evaluation in case of suspected AVP deficiency is challenging and simplified approaches with high diagnostic accuracies are needed. Once correctly diagnosed with AVP deficiency treatment with desmopressin (AVP receptor analogue) is started to control for polyuria. However, desmopressin treatment is accompanied by a high prevalence of hyponatremia. On the other hand, restriction to desmopressin and fluid intake during hospitalisation, partly explained by confusion with ‘diabetes mellitus’, may lead to severe consequences. Data on methods to counteract the risk of hyponatremia and data on treatment errors during hospitalisations are lacking. Additionally, hypothalamic-pituitary disruptions leading to AVP deficiency could also disturb the oxytocin system with subsequent clinical consequences. However, oxytocin deficiency has never been defined as pituitary entity and no provocation test is available to test for an oxytocin deficiency.
Objective: First, to investigate whether the glucagon provocation test might provide a novel diagnostic test in the differential diagnosis of AVP deficiency. Second, to assess patients' perspectives regarding their disease management, psychological comorbidities, and view for renaming ‘diabetes insipidus’ to avoid confusion with ‘diabetes mellitus’. And third, to investigate 3,4-methylene-dioxymethamphetamine (MDMA) as a novel provocation test to reveal an OXT deficiency.
Methods: The first study is a double-blind, randomised, placebo-controlled trial including 22 healthy controls, ten patients with AVP deficiency, and ten patients with primary polydipsia (PP). The second study is a cross-sectional, web-based survey including 1034 patients with AVP deficiency. The third study is a randomised, placebo-controlled, double-blind, cross-over trial including 15 patients with AVP deficiency and 15 matched healthy controls.
Results: First, in patients with AVP deficiency, copeptin showed no relevant increase in response to glucagon, whereas copeptin was strongly stimulated in patients with primary polydipsia (PP). Glucagon stimulation demonstrated a high diagnostic accuracy in differentiating between both conditions. Second, once diagnosed and treated with desmopressin, a high prevalence of hyponatremia leading to hospitalisations was observed. Patients who routinely omitted or delayed desmopressin to allow intermittent aquaresis had a significantly lower prevalence of hyponatraemia than those unaware of this approach. Of patients who had to be hospitalised for any medical reason, one in seven reported symptoms of dehydration due to desmopressin restriction or/and wrong fluid management. One in three patients reported psychological changes subjectively associated with their AVP deficiency. In total, 85% of patients supported renaming the disease. Third, in patients, there was only a minimal OXT increase in response to MDMA, while in healthy controls, there was a robust eight-fold OXT increase.
Discussion: First, glucagon-stimulated copeptin has the potential for a safe, novel, and precise test in the differential diagnosis of AVP-D. Second, our data show a high prevalence of treatment-associated side-effects, mismanagement during hospitalisation, psychological comorbidities, and clear support for renaming the disease; our data are the first to indicate the value of routinely omitting or delaying desmopressin. Third, these results lay the basis for OXT deficiency as a new hypothalamic-pituitary entity
HMGA1-pseudogene expression is induced in human pituitary tumors
Get PDFNumerous studies have established that High Mobility Group A (HMGA) proteins play a pivotal role on the onset of human pituitary tumors. They are overexpressed in pituitary tumors, and, consistently, transgenic mice overexpressing either the Hmga1 or the Hmga2 gene develop pituitary tumors. In contrast with HMGA2, HMGA1 overexpression is not related to any rearrangement or amplification of the HMGA1 locus in these tumors. We have recently identified 2 HMGA1 pseudogenes, HMGA1P6 and HMGA1P7, acting as competitive endogenous RNA decoys for HMGA1 and other cancer related genes. Here, we show that HMGA1 pseudogene expression significantly correlates with HMGA1 mRNA levels in growth hormone and nonfunctioning pituitary adenomas likely inhibiting the repression of HMGA1 through microRNAs action. According to our functional studies, these HMGA1 pseudogenes enhance the proliferation and migration of the mouse pituitary tumor cell line, at least in part, through their upregulation. Our results point out that the overexpression of HMGA1P6 and HMGA1P7 could contribute to increase HMGA1 levels in human pituitary tumors, and then to pituitary tumorigenesis
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