1,721,007 research outputs found
HLA class II linkage disequilibrium and haplotype evolution in the Cayapa Indians of Ecuador
No full textDNA-based typing of the HLA class II loci in a sample of the Cayapa Indians of Ecuador reveals several lines of evidence that selection has operated to maintain and to diversify the existing level of polymorphism in the class II region. As has been noticed for other Native American groups, the overall level of polymorphism at the DRB1, DQA1, DQB1, and DPB1 loci is reduced relative to that found in other human populations. Nonetheless, the relative evenness in the distribution of allele frequencies at each of the four loci points to the role of balancing selection in the maintenance of the polymorphism. The DQA1 and DQB1 loci, in particular, have near-maximum departures from the neutrality model, which suggests that balancing selection has been especially strong in these cases. Several novel DQA1-DQB1 haplotypes and the discovery of a new DRB1 allele demonstrate an evolutionary tendency favoring the diversification of class LI alleles and haplotypes. The recombination interval between the centromeric DPB1 locus and the other class II loci will, in the absence of other forces such as selection, reduce disequilibrium across this region. However, nearly all common alleles were found to be part of DR-DP haplotypes in strong disequilibrium, consistent with the recent action of selection acting on these haplotypes in the Cayapa
Ljungan virus detected in bank voles (Myodes glareolus) and yellow-necked mice (Apodemus flavicollis) from Northern Italy
No full textIdentified in 1998, Ljungan virus (LV; Picornaviridae) causes type 1 diabetes-like symptoms and myocarditis in bank voles (Myodes glareolus) from Sweden and Denmark, and may be a zoonotic agent of several important diseases (e.g., intrauterine fetal death, type 1 diabetes, Guillain-Barré syndrome, and myocarditis). Using a real-time reverse transcriptase-polymerase chain reaction assay and sequence analysis, we detected LV in bank voles, and for the first time, in yellow-necked mice (Apodemus flavicollis) collected during 2006 from a site in northern Italy. The global distribution of LV and its role as a mammalian pathogen deserve further attentio
Ljungan virus a candidate virus in association with several human diseases found in bank voles and yellow-necked mice for the first time in northern Italy
Get PDFThe Ljungan (picorna) virus (LV) was first isolated in 1998 from Swedish bank voles (Myodes glareolus) after clinically recognizable type-1 diabetes-like symptoms were noted in this species in Denmark. LV has subsequently been shown to induce type-2-like diabetes, as well as uterine resorptions, malformations, and neonatal death in CD-1 laboratory house mice, and has been found in wild voles in the USA, as well as in lemmings and laboratory rats. Intriguingly, the incidence of type-1 diabetes, Guillain-Barré syndrome and myocarditis in the human population is correlated with rodent population cycles in Sweden. In addition, LV has been associated with intrauterine fetal death in Sweden, and a preliminary study showed that children newly diagnosed with type-1 diabetes have significantly increased levels of LV antibodies compared to controls. It has been hypothesized that the bank vole as well as other small rodents could act as reservoirs and/or vectors of LV that may be a zoonotic agent several human diseases or pathologies, including economically important type-1 diabetes. Consequently, knowledge of the distribution LV among wild and domestic mammal species is crucial to assess its potential importance as a human pathogen, identify possible zoonotic sources of the virus and lay groundwork for possible vaccine development. Here we provide a review of the current understanding of the ecopathology of LV and present the first results from southern Europe. Using Real Time RT PCR, LV was confirmed in 50% (10/20) of bank voles and in 10% (2/20) of yellow-necked mice (Apodemus flavicollis) collected from an alpine meadow in northern Italy during 2006. LV-positive animals included males and females, adults and subadults. This is the first time LV has been reported in Italy and in yellow-necked mice. These results significantly increase the geographical and species range of LV. We believe the global distribution of this picornavirus, and its role as a zoonotic agent, deserve further attention
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
The association of specific HLA class I and II alleles with type 1 diabetes among Filipinos
No full textDispelling 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
- …
