1,721,022 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
Marine omega-3 phospholipids suppress hepatic steatosis by a complex inhibition of biosynthetic pathways in dietary obese mice [Mus Musculus]
No full textBackground & Aims: Non-alcoholic fatty liver disease accompanies obesity and is independently associated with cardiovascular disease. Omega-3 fatty acids, such as docosahexaenoic (DHA) and eicosapentaenoic (EPA) acid, reduce the risk of cardiovascular disease due to their anti-inflammatory and hypolipidemic effects. Recent data suggested that metabolic effects of EPA/DHA as marine phospholipids could be stronger than triglycerides (fish oil). We characterised the mechanisms underlying beneficial effects of EPA/DHA phospholipids alone or in combination with antidiabetic drugs on hepatosteatosis in dietary obese mice. Methods: Male C57BL/6N mice were fed for 7 weeks a corn oil-based high-fat diet (cHF) or subjected to cHF-based interventions: (i) cHF with DHA/EPA as phosphatidylcholine-rich concentrate replacing ~10 % of dietary lipids (PC); ii) cHF with a low-dose of thiazolidinedione rosiglitazone (10 mg/kg diet), which retains some of the beneficial effects but also potentiates hepatic lipid accumulation (R); and iii) PC+R. Metabolic profiling together with hepatic gene expression and lipidomic analyses were performed. Results: PC and PC+R prevented weight gain and glucose intolerance induced by cHF, while all interventions reduced abdominal fat and plasma triglycerides. In contrast to R, PC and PC+R lowered hepatic and plasma cholesterol and eliminated hepatosteatosis. Hepatic microarray analysis primarily revealed a complex downregulation of lipogenic and cholesterol biosynthesis pathways by PC. Lipidomic analysis identified arachidonic acid, DHA and EPA in hepatic phosphatidylcholine and phosphatidylethanolamine fractions as the most important variables. Importantly, down-regulation of genes within these pathways was enlarged by phospholipid versus triglyceride forms of EPA/DHA in an independent experiment. Conclusions: Obesity-associated hepatosteatosis and hypercholesterolemia were ameliorated by marine phospholipids in association with a complex inhibition of biosynthetic pathways in liver. Stronger effects of phospholipids versus triglyceride form of EPA/DHA suggest their preferential use in the prevention and possible treatment of obesity-associated metabolic hepatic dysfunctions
Dietary calcium inhibits colitis development in HLA-B27 transgenic rats [Rattus norvegicus]
No full text(Submitter supplied) Background and Aims: We have shown in several controlled rat and human infection studies that dietary calcium improves intestinal resistance and strengthens the mucosal barrier. Reinforcement of gut barrier function is also relevant for inflammatory bowel disease (IBD). Therefore, we investigated the effect of supplemental calcium on spontaneous colitis development in HLA-B27 transgenic rats, an experimental animal model of IBD. Methods: HLA-B27 transgenic rats were fed a purified high-fat diet containing either a low or high calcium content (30 and 120 mmol CaHPO4/kg diet, respectively) for almost 7 weeks. Inert chromium ethylenediamine-tetraacetic acid (CrEDTA) was added to the diets to quantify intestinal permeability by measuring urinary CrEDTA excretion. Relative fecal dry-weight was determined to quantify diarrhea. Colonic inflammation was determined histologically, and by measuring mucosal interleukin-1β. In addition, colonic mucosal gene expression of individual rats was analyzed, using whole genome microarrays. Interesting results were verified by Q-PCR. Results: The high-calcium diet significantly prevented the increase in intestinal permeability and diarrhea with time in HLA-B27 rats developing colitis as compared to the low-calcium group. The histological colitis score and mucosal interleukin-1β levels were lower in high-calcium fed rats. Supplemental calcium prevented the colitis-induced increase in the expression of extracellular matrix remodeling genes (e.g. matrix metalloproteinases, procollagens and fibronectin), which was confirmed by Q-PCR. Conclusions: Dietary calcium inhibits colitis development in HLA-B27 transgenic rats. Calcium prevents the colitis-related increase in intestinal permeability, diminishes diarrhea, and lowers the inflammatory response in the mucosa, resulting in less extracellular matrix breakdown
Induction of lipid oxidation gene expression by polyunsaturated fatty acids of marine origin in small intestine of mice [Mus musculus]
No full textDietary polyunsaturated fatty acids (PUFA) act as potent natural hypolipidemics and are linked to many health benefits in humans and in animal models. Mice fed long-term a high fat diet, in which medium-chain alpha linoleic acid (ALA) was partially replaced by long-chain docosahexaenoic (DHA) and eicosapentaenoic (EPA) fatty acids, showed reduced accumulation of body fat and prevention of insulin resistance, besides increased mitochondrial beta-oxidation in white adipose tissue and decreased plasma lipids. ALA, EPA and DHA all belong to PUFA of n-3 series. The intestine is a gatekeeper organ for ingested lipids. To examine the potential contribution of the intestine in the beneficial effects of EPA and DHA, this study assessed gene expression changes using whole genome microarray analysis on small intestinal scrapings. The main biological process affected was lipid metabolism. Fatty acid uptake, peroxisomal and mitochondrial beta-oxidation, and omega-oxidation of fatty acids were all increased. Quantitative real time PCR and intestinal fatty acid oxidation measurements ([14C(U)]-palmitate) confirmed significant gene expression differences in a dose-dependent manner. Furthermore, no major changes in the expression of lipid metabolism genes were observed in colonic scrapings. In conclusion, we show that marine n-3 fatty acids regulate small intestinal gene expression patterns. Since this organ contributes significantly to whole organism energy use, this adaptation of the small intestine may contribute to the complex and observed beneficial physiological effects of these natural compounds under conditions that will normally lead to development of obesity and diabetes
Adipose tissue failure and mitochondria as a possible target for improvement by bioactive food components
No full textPurpose of review: Adipose tissue is an essential, highly dynamic and metabolically active tissue that vigorously communicates to support its primary function: the storage of lipids. It performs this function to secure energy supply and prevent lipotoxicity. Adipose tissue is essential for maintaining a healthy glucose and lipid homeostasis and failure results in disease. This review discusses causes of adipose tissue failure and four categories of bioactive food components that may help to prevent this. Recent findings: Based on recent findings, it is argued that initial adipose failure following long-term excess energy intake may be the result of reduced mitochondrial capacity associated with altered mitochondrial reactive oxygen species signaling and adipose tissue hypoxia. Current data suggest that different classes of bioactive food components, including vitamin B3, retinoids, fatty acids and polyphenols, may have the potential to modulate mitochondrial function and consequently prevent adipose dysfunction in obesity. Summary: It seems most attractive to aim nutritional intervention at the prevention of initial adipose dysfunction and hence to target dietary intervention at improvement of mitochondrial function
Short-term, high fat-feeding-induced changes in white adipose tissue gene expression are highly predictive for long-term changes
No full textUsing standardized, semipurified diets is a crucial factor for reproducibility of experimental nutritional studies. For the purpose of comparability and integration of research, two European consortia, Mitofood and BIOCLAIMS, proposed an AIN-93-based standard reference diet, the standardized BIOCLAIMS low-fat diet (LFD) as well as a high-fat diet (HFD). In order to evaluate the BIOCLAIMS LFD and HFD, we performed short-term (5 days) and long-term (12 weeks) feeding experiments using male C57BL/6 mice. The HFD has the same composition as the LFD except the fat content is increased to 40% energy in exchange for carbohydrates. Both diets were accepted by the animals and proof of principle was given that the BIOCLAIMS HFD increases body weight and body fat and affects glucose homeostasis. Short-term feeding trials (5 days) were performed in order to identify metabolic and molecular parameters which can serve as acute predictors for metabolic disorders due to high-fat diet-induced obesity. We analyzed gene expression in gonadal white adipose tissue of short- and long-term fed animals with whole genome microarrays. The BIOCLAIMS HFD strongly influenced gene expression in white adipose tissue after short- and long-term intervention. A total number of 973 and 4678 transcripts were significantly different between both diets after 5 days feeding and 12 weeks feeding, respectively. A total number of 764 transcripts encoding 549 genes were significantly differentially regulated between LF and HF animals after 12 weeks feeding as well as after 5 days feeding. Of these 549 overlapping genes, a substantial number (434 genes) were expressed at a lower level and 115 genes were expressed at a higher level in the HF mice compared to the LF mice. Without exception, all genes were regulated equally. Pathway analysis revealed a prominent role for genes involved in lipid metabolism, carbohydrate metabolism and oxidative phosphorylation. This was confirmed by quantitative real-time reverse transcription PCR. The high predictive value of gene expression changes in our short-term study compared to long-term high fat feeding is a promising step to get well-defined, early biomarkers that could shorten animal trials considerably and allow a more rapid and efficient screening of different compounds
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
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