1,721,651 research outputs found
Abnormal cardiac energetics in patients carrying the A3243G mtDNA mutation measured in vivo using phosphorus MR spectroscopy
No full textDoes mitochondrial DNA predispose to neuromyelitis optica (Devic's disease)?
No full textNeuromyelitis optica (NMO) has similarities with Leber hereditary optic neuropathy (LHON, MIM 535 000) which is primarily due to mutations of mitochondrial DNA (mtDNA) that disrupt complex I of the respiratory chain. In this study, we found no evidence to support the hypothesis that ancient mtDNA polymorphisms are associated with or predispose to NMO. A study of this size cannot exclude a subtle increased susceptibility, especially if conferred by rare mtDNA variants in a region not directly sequenced here. However, this would be very difficult to demonstrate, given the rarity of NMO and the samples sizes required to show a convincing association between mtDNA variants and a complex disease
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
Mitochondrial Disorders Due to Mutations in the Nuclear Genome
No full text\ua9 2015 Elsevier Inc. All rights reserved. Mitochondrial disorders are caused by mutations in nuclear DNA and mitochondrial DNA (mtDNA). Nuclear-encoded mitochondrial disorders have emerged as a major cause of inherited neurometabolic disease. As with mitochondrial DNA-encoded disorders, they characteristically affect multiple neurological systems, and also often involve other non-neurological organs and tissues. They can present at any age, from early-onset severe encephalomyopathies in children, through to late-onset, slowly progressive adult neurodegenerative disorders.Nuclear-encoded mitochondrial disorders can be inherited as an autosomal dominant, autosomal recessive, or X-linked recessive trait. The recessive forms are more common in consanguineous individuals but usually appear as isolated cases in an outbred population. This inheritance pattern contrasts with mitochondrial DNA-encoded mitochondrial disorders, which are inherited down the maternal line.Some nuclear-encoded mitochondrial disorders have the characteristic clinical phenotype, prompting early genetic testing of specific nuclear genes. However, given the overlapping spectrum for clinical phenotypes, a systematic approach is advocated in all but the most obvious cases. This should incorporate clinical investigations aimed at building a clear picture of the phenotype, and biochemical studies in an affected tissue, which guides nuclear genetic testing. The impact of exome and whole-genome sequencing will dramatically change the diagnostic approach in the near future.Current research activity is focused on providing a comprehensive molecular diagnosis to enable reliable genetic counseling and prenatal testing. Genetically defined cohorts are being assembled throughout the world, enabling the first natural history studies and treatment trials in mitochondrial disease. It is likely that new treatments will become available in the near future
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