1,720,971 research outputs found
Untersuchung des Transkriptoms bei temperaturbehandelten genetisch weiblichen und genetisch männlichen Tilapien (Oreochromis niloticus)
No full textUntersuchung des Transkriptoms bei temperaturbehandelten genetisch weiblichen und genetisch männlichen Tilapien (Oreochromis niloticus)
No full textWhole transcriptome analysis in brains from BSE-infected macaques
No full textPrion diseases are neurodegenerative disorders that affect both humans and animals. The molecular mechanisms underlying prion replication and subsequent degeneration of the central nervous system are still poorly understood. In an attempt to identify molecules that are putatively involved in the etiology of these diseases, we conducted a whole transcriptome analysis with brain tissue from BSE-infected and uninfected cynomolgus macaques (M. fascicularis). Total RNA from the gyrus frontalis region of seven BSE-infected and five noninfected control macaques was isolated. The integrity of the RNA was assessed using an Agilent 2100 Bioanalyzer. The RNA was reverse-transcribed, labeled and analyzed on an GeneChip® Rhesus Macaque Genome Array (Affymetrix) containing 52,024 Macaca mulatta probe sets to monitor the gene expression of approximately 47,000 transcripts. Bioinformatic analysis revealed that about 100 transcripts were significantly up-or down-regulated more than twofold. Beside others, we found up-regulation of α1-antichymotrypsin, which has also been described in scrapie-infected mice and Alzheimer’s disease. We are currently validating the most interesting candidates using quantitative RT-PCR. Our approach may help to identify genes that are crucial to prion disease processes and may become potential targets for diagnostic and therapeutic strategies
Physical activity delays hippocampal neurodegeneration and rescues memory deficits in an Alzheimer disease mouse model
No full textThe evidence for a protective role of physical activity on the risk and progression of Alzheimer’s disease (AD) has been growing in the last years. Here we studied the influence of a prolonged physical and cognitive stimulation on neurodegeneration, with special emphasis on hippocampal neuron loss and associated behavioral impairment in the Tg4-42 mouse model of AD. Tg4-42 mice overexpress Aβ4-42 without any mutations, and develop an age-dependent hippocampal neuron loss associated with a severe memory decline. We demonstrate that long-term voluntary exercise diminishes CA1 neuron loss and completely rescues spatial memory deficits in different experimental settings. This was accompanied by changes in the gene expression profile of Tg4-42 mice. Deep sequencing analysis revealed an upregulation of chaperones involved in endoplasmatic reticulum protein processing, which might be intimately linked to the beneficial effects seen upon long-term exercise. We believe that we provide evidence for the first time that enhanced physical activity counteracts neuron loss and behavioral deficits in a transgenic AD mouse model. The present findings underscore the relevance of increased physical activity as a potential strategy in the prevention of dementia.Open-Access Publikationsfonds 2016Open-Access-Publikationsfonds 201
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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