123,046 research outputs found

    Antibodies to the RNase H domain of hepatitis B virus P protein are associated with ongoing viral replication.

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    Antibodies against the RNase H domain of human hepatitis B virus P protein(s) are frequent markers of acute and chronic virus infection (T. Weimer, K. Weimer, Z.-X. Tu, M.-C. Jung, G. R. Pape, and H. Will, J. Immunol. 143:3750-3756, 1989). In the present study, these antibodies were determined in serial serum samples of experimentally infected chimpanzees and naturally infected human patients with acute and chronic hepatitis B virus infection. Anti-P antibodies were found in the sera of both chimpanzees and humans early in infection shortly after the immunoglobulin M anti-HBc response; they persisted in chronic carriers with ongoing viral replication but declined and disappeared at the time of virus clearance from the sera. These data demonstrate that antibodies to the RNase H domain of the hepatitis B virus P protein are early markers of infection and a signal of ongoing virus replication. Falling titers indicate the decline or end of active virus production and may therefore be a prognostic sign of virus elimination in natural infection and after antiviral therapy

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We 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

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    We 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

    The construction of Karen Karnak: The multi-author-function

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    This thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author

    Hypoderma sinense: solving a century-old enigma

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    Among the species of Hypoderma (Diptera: Oestridae) that have been described and named over the last three centuries, Hypoderma sinense Pleske has been the subject of several scientific discussions. Hypoderma sinense was described by T. Pleske in 1926 on the basis of only three females collected by the Russian explorer P. K. Kozlov nearly 25 years earlier during a scientific expedition to China (1900-1901). This species was examined by the foremost oestrid authorities and synonomized with H. lineatum. Recently a unique, unidentified species of Hypoderma was observed to infect cattle and yaks in China. Molecular and morphological observations confirmed the unique nature of the third-stage larvae. This data initiated a debate within the scientific community regarding the proper name of this species, in particular with reference to previous taxonomical discussion on the validity of H. sinense. The present work provides a historical overview of the Russian scientific expeditions that collected the specimens and of the explorers and the entomologists who contributed to the description of H. sinense. The morphological examination of the original type material of H. sinense and the comparison with females of H. lineatum indicated that the H. sinense lectotype, deposited at the Zoological Institute of the Russian Academy of Sciences, St Petersburg, was within the range of variation of H. lineatum. Comparisons of the cox1 (688 bp) sequence obtained from the leg of a paralectotype of H. sinense with those of H. bovis (Linneaus), H. lineatum (De Villers) and of a sixth valid species of Hypoderma identified as "H. sinense" available in GenBank revealed differences of 9.7%, 7.2% and 0.3%, respectively. On the basis of these results, we concluded that the nominal species H. sinense should be treated as valid

    The role of phase separation for self-organized surface pattern formation by ion beam erosion and metal atom co-deposition

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    We investigate the ripple pattern formation on Si surfaces at room temperature during normal incidence ion beam erosion under simultaneous deposition of different metallic co-deposited surfactant atoms. The co-deposition of small amounts of metallic atoms, in particular Fe and Mo, is known to have a tremendous impact on the evolution of nanoscale surface patterns on Si. In previous work on ion erosion of Si during co-deposition of Fe atoms, we proposed that chemical interactions between Fe and Si atoms of the steady-state mixed FexSi surface layer formed during ion beam erosion is a dominant driving force for self-organized pattern formation. In particular, we provided experimental evidence for the formation of amorphous iron disilicide. To confirm and generalize such chemical effects on the pattern formation, in particular the tendency for phase separation, we have now irradiated Si surfaces with normal incidence 5 keV Xe ions under simultaneous gracing incidence co-deposition of Fe, Ni, Cu, Mo, W, Pt, and Au surfactant atoms. The selected metals in the two groups (Fe, Ni, Cu) and (W, Pt, Au) are very similar regarding their collision cascade behavior, but strongly differ regarding their tendency to silicide formation. We find pronounced ripple pattern formation only for those co deposited metals (Fe, Mo, Ni, W, and Pt), which are prone to the formation of mono and disilicides. In contrast, for Cu and Au co-deposition the surface remains very flat, even after irradiation at high ion fluence. Because of the very different behavior of Cu compared to Fe, Ni and Au compared to W, Pt, phase separation toward amorphous metal silicide phases is seen as the relevant pro-cess for the pattern formation on Si in the case of Fe, Mo, Ni, W, and Pt co-deposition.Deutsche Forschungsgemeinschaft [HO1125/20-1,2

    Contribution of Information and Communication Technology (ICT) in Country’S H-Index

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    The aim of this study is to examine the effect of Information and Communication Technology (ICT) development on country’s scientific ranking as measured by H-index. Moreover, this study applies ICT development sub-indices including ICT Use, ICT Access and ICT skill to find the distinct effect of these sub-indices on country’s H-index. To this purpose, required data for the panel of 14 Middle East countries over the period 1995 to 2009 is collected. Findings of the current study show that ICT development increases the H-index of the sample countries. The results also indicate that ICT Use and ICT Skill sub-indices positively contribute to higher H-index but the effect of ICT access on country’s H-index is not clear
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