1,721,015 research outputs found
VH gene usage in IgE in patients with atopic asthma
No full textThe spectrum of VH-D-JH sequences of IgE antibodies from atopic asthmatic patients has been studied.An initial investigation of these sequences from the spleen of an asthmatic patient revealed preferential usage of the VH5 family, with 5 out of 14 clones being derived from this family. A control PCR of the same VH primers in combination with JH yielded only 1 out of 13 sequences from the VH5 family indicating preferential usage of VH5 only for IgE. Clones were also obtained from the larger families, VH3 and VH4. All the sequences showed extensive somatic hypermutation, with some of the VH3 and VH4-derived clones demonstrating evidence of conventional antigen selection.Using the same approach with peripheral blood from 7 patients, the minor VH5 family was represented in 17% of VH-Cε transcripts. By contrast, control PCRs with IgM primers replacing those for IgE obtained a 5% incidence of the VH5 family. These findings have led to the suggestion that common allergens may be acting as B cell superantigens and driving the selection of the VH5 genes.The results point to three processes that influence the generation of IgE antibodies.1) Preferential usage of the VH5 genes, indicative of stimulation by a superantigen.2) Extensive somatic hypermutation, with hotspots common to VH5 genes.3) Conventional antigen selection of higher affinity mutants and B cells expressing other VH genes.Serum levels of antigen specific IgG4 are often raised along with IgE in allergic individuals. These IgG4 antibodies may have a protective role as 'blocking antibodies', reducing the harmful effects of IgE by competing for antigen. The clonal relationship of IgG4 and IgE in allergic patients has been investigated by PCR. In ¾ patients VH5-Cγ4 transcripts were identified clonally related to IgE. These findings suggest that an IgM precursor cell may commonly switch to both IgG4 and IgE.</p
Gendered patterns of migration in rural South Africa
Get PDFGender is increasingly recognised as fundamental to understanding migration processes, causes, and consequences. In South Africa, it is intrinsic to the social transformations fueling high levels of internal migration and complex forms of mobility. Although female migration in Africa has often been characterised as less prevalent than male migration and primarily related to marriage, in South Africa, a feminisation of internal migration is underway, fueled by women's increasing labour market participation. In this paper, we report sex differences in patterns, trends, and determinants of internal migration based on data collected in a demographic surveillance system between 2001 and 2006 in rural KwaZulu-Natal. We show that women were somewhat more likely than men to undertake any migration, but sex differences in migration trends differed by migration flow, with women more likely to migrate into the area than men and men more likely to out-migrate. Out-migration was suppressed by marriage, particularly for women, but most women were not married; both men's and women's out-migrations were undertaken mainly for purposes of employment. Over half of female out-migrations (vs 35% of male out-migrations) were to nearby rural areas. The findings highlight the high mobility of this population and the extent to which gender is intimately related to the processes determining migration. We consider the implications of these findings for the measurement of migration and mobility, in particular for health and social policy and research among highly mobile populations in southern Africa
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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