125,476 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Regulation von B-Zell-Signalprozessen durch das Latente Membranprotein 2A des Epstein-Barr-Virus
No full textYigit G. Regulation von B-Zell-Signalprozessen durch das Latente Membranprotein 2A des Epstein-Barr-Virus. Bielefeld (Germany): Bielefeld University; 2008.Das onkogene Epstein-Barr-Virus (EBV), der Erreger der infektiösen Mononukleose, gehört zur Gruppe der humanpathogenen [gamma]-Herpesviren. Durch Etablierung eines latenten Zustands, in dem keine infektiösen Viruspartikel gebildet werden, kann das Virus seiner vollständigen Eliminierung durch das Immunsystem entgehen und im Organismus persistieren. EBV etabliert die Latenz in einer Population ruhender B-Gedächtniszellen, aus denen es reaktiviert werden kann und den lytischen Zyklus initiieren kann. Das Latente Membranprotein (LMP) 2A von EBV ist der Lage, Signalleitungsprozesse in B-Zellen zu beeinflussen. Bisherige Untersuchungen der LMP2A-vermittelten Signalleitung stützen sich überwiegend auf in vitro mit EBV infizierte, sogenannte Lymphoblastoide Zelllinien (LCLs). In LCLs induziert die Expression von LMP2A die konstitutive Phosphorylierung BCR-proximaler Signalproteine und inhibiert gleichzeitig die BCR-abhängige Ca2+-Mobilisierung. Allerdings exprimieren LCLs weitere EBV-codierte Proteine, so dass sich die isolierte Funktion von LMP2A in diesem Zellsystem nicht eindeutig bestimmen lässt.
Im Rahmen dieser Arbeit sollte die LMP2A-vermittelte Signalleitung in B-Lymphocyten in statu nascendi und unabhängig von weiteren viralen Proteinen untersucht werden. Dazu wurde ein Cre/loxP-basiertes Expressionssystem zur Analyse der LMP2A-Signalleitung in DT40 B-Lymphocyten verwendet, das es erlaubt, die Expression von LMP2A gezielt zu regulieren. Mit Hilfe dieses Systems konnte nachgewiesen werden, dass LMP2A ligandenunabhängig BCR-proximale Signalwege aktivieren kann. Die Aktivierung beschränkt sich dabei nicht wie in LCLs auf membrannahe Signalprozesse wie die Phosphorylierung der Signalproteine Lyn, Syk und SLP-65, sondern umfasst auch die Aktivierung von PLC-[gamma]2, einem Schlüsselenzym der cytosolischen Ca2+-Mobilisierung. Die Expression von LMP2A induziert Oszillationen der intrazellulären Ca2+-Konzentration, die zur Aktivierung der Transkriptionsfaktoren NFAT und NF-kB führen. Diese konstitutive Signalleitung durch LMP2A ist abhängig von der Membrantopologie des cytosolischen N-Terminus. Darüber hinaus konnte gezeigt werden, dass diese durch LMP2A vermittelten Signale die Aktivierung des EBV-Promotors pZ induzieren und so zur Initiation des lytischen Replikationszyklus von EBV beitragen können
Pragmatic Case Studies as a Source of Unity in Applied Psychology
No full textTo unify or not to unify applied psychology: that is the question. In this article we review pendulum swings in the historical efforts to answer this question—from a comprehensive, positivist, “top-down,” deductive yes between the 1930s and the early 60s, to a postmodern no since then. A rationale and proposal for a limited, “bottom-up,” inductive yes in applied psychology is then presented, employing a case-based paradigm that integrates both positivist and postmodern themes and components. This paradigm is labeled “pragmatic psychology” and, its specific use of case studies, the “Pragmatic Case Study Method” (“PCS Method”). We call for the creation of peer-reviewed journal-databases of pragmatic case studies as a foundational source of unifying applied knowledge in our discipline. As one example, the potential of the PCS Method for unifying different angles of theoretical regard is illustrated in an area of applied psychology, psychotherapy, via the case of Mrs. B. The article then turns to the broader historical and epistemological arguments for the unifying nature of the PCS Method in both applied and basic psychology.Peer reviewe
Fetal arterial and venous Doppler in growth restricted fetuses for the prediction of perinatal complications
No full textOzyuncu O, Saygan-Karamursel B, Armangil D, Onderoglu LS, Yigit S, Velipasaoglu M, Deren O. Fetal arterial and venous Doppler in growth restricted fetuses for the prediction of perinatal complications. Turk J Pediatr 2010; 52: 384-392
Dr. Edwin Wright Collection: Author Unknown
No full textNotes - The author relates several short stories about his neighbours including Alex McDonell, homesteading and life around Meanook and Athabasca (1 page
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Definition of the Native and Denatured Type II Collagen Binding Site for Fibronectin Using a Recombinant Collagen System
No full textEpstein-Barr virus LMP2A signaling <it>in statu nascendi </it>mimics a B cell antigen receptor-like activation signal
No full textAbstract Background The latent membrane protein (LMP) 2A of Epstein-Barr virus (EBV) is expressed during different latency stages of EBV-infected B cells in which it triggers activation of cytoplasmic protein tyrosine kinases. Early studies revealed that an immunoreceptor tyrosine-based activation motif (ITAM) in the cytoplasmic N-terminus of LMP2A can trigger a transient increase of the cytosolic Ca2+ concentration similar to that observed in antigen-activated B cells when expressed as a chimeric transmembrane receptor. Even so, LMP2A was subsequently ascribed an inhibitory rather than an activating function because its expression seemed to partially inhibit B cell antigen receptor (BCR) signaling in EBV-transformed B cell lines. However, the analysis of LMP2A signaling has been hampered by the lack of cellular model systems in which LMP2A can be studied without the influence of other EBV-encoded factors. Results We have reanalyzed LMP2A signaling using B cells in which LMP2A is expressed in an inducible manner in the absence of any other EBV signaling protein. This allowed us for the first time to monitor LMP2A signaling in statu nascendi as it occurs during the EBV life cycle in vivo. We show that mere expression of LMP2A not only stimulated protein tyrosine kinases but also induced phospholipase C-γ2-mediated Ca2+ oscillations followed by activation of the extracellular signal-regulated kinase (Erk) mitogen-activated protein kinase pathway and induction of the lytic EBV gene bzlf1. Furthermore, expression of the constitutively phosphorylated LMP2A ITAM modulated rather than inhibited BCR-induced Ca2+ mobilization. Conclusion Our data establish that LMP2A expression has a function beyond the putative inhibition of the BCR by generating a ligand-independent cellular activation signal that may provide a molecular switch for different EBV life cycle stages and most probably contributes to EBV-associated lymphoproliferative disorders.</p
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
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