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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
Deciphering the role of STAT1 signaling in myeloid cells in extramedullary erythropoiesis and megakaryopoiesis during murine cytomegalovirus (MCMV) infection
No full textMaster thesis - University of Veterinary Medicine Vienna - 2022Extramedullary haematopoiesis (EMH) is the formation of blood cells outside the bone marrow. In adults, EMH compensates for an increased blood cell demand during infection and inflammation, in particular when bone marrow haematopoiesis in suppressed. Signal transducer and activator of transcription 1 (STAT1) is a key transcription factor used by all types of interferons (IFNs). We have shown previously that mice lacking STAT1 in myeloid cells (Stat1ΔM/PMN) have impaired EMH upon infection with murine cytomegalovirus (MCMV) and during sterile inflammation, as evidenced by lower numbers of erythroblasts and megakaryocytes in the spleen. To better understand the mechanism, we assessed the abundance and the proliferative state of their immediate precursors, the colony-forming unit erythroid (CFU-E) and megakaryocyte progenitors (MkP), in spleen and bone marrow at day 3 and day 5 post infection. In addition, we measured levels of cytokines and chemokines that are important in haematopoiesis in the spleen. We show that MCMV infection induces the appearance of CFU-E and MkP in spleens, whereas their frequencies in the bone marrow remains unchanged. The abundance and proliferative state of CFU-E was similar between Stat1ΔM/PMN mice and littermate controls (Stat1fl/flmice), indicating that STAT1 signaling in myeloid cells affects erythropoiesis at later developmental stages, such as the differentiation of CFU-E into erythroblasts or erythroblast proliferation/survival. In contrast, Stat1ΔM/PMN mice had an even higher frequency of splenic MkP than littermate controls, which was associated with a slightly increased proliferative rate. Albeit further studies are needed, this may indicate that myeloid cells promote the differentiation of MkP into megakaryocytes through STAT1-dependent mechanisms. In the bone marrow, the frequency and proliferative state of MkP was similar between Stat1ΔM/PMN and control mice. With respect to cytokines/chemokines, we found increased MCMV-induced upregulation of splenic interleukin-6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), IFNγ and stem cell factor (SCF) and increased downregulation of IL-11 in Stat1ΔM/PMN compared to control mice. Erythropoietin (EPO), C-X-C motif chemokine 12 (CXCL12) and leukemia inhibitory factor (LIF) levels were similar in mice of the two genotypes. Taken together, our data indicate that STAT1 in myeloid cell regulates splenic EMH at multiple levels and support the notion that EMH does not simply mirror haematopoietic responses in the bone marrow.Masterarbeit - Veterinärmedizinische Universität Wien - 2022Die Blutbildung außerhalb des Knochenmarks wird als extramedulläre Hämatopoese (EMH) bezeichnet. Im adulten Organismus kommt EMH vor, wenn durch Infektionen oder Entzündungen die Blutbildung im Knochenmark nicht ausreichend ist. “Signal transducer and activator of transcription 1” (STAT1) ist ein wichtiger Transkriptionsfaktor, der von allen Typen an Interferonen (IFN) benutzt wird. Studien aus unserem Labor zeigten, dass Mäuse, denen STAT1 in myeloiden Zellen fehlt (Stat1ΔM/PMN Mäuse), nach Infektion mit dem murinen Cytomegalovirus (MCMV) und während steriler Entzündung, mangelhafte EMH mit einer stark reduzierten Anzahl an Erythroblasten und Megakaryozyten in der Milz aufweisen. Um den Mechanismus besser zu verstehen, haben wir die Anzahl und Proliferation der unmittelbaren Vorläufer von Erythroblasten und Megakaryozyten, den CFU-E und MkP, in der Milz und dem Knochenmark am Tag 3 und 5 nach der MCMV Infektion bestimmt. Zusätzlich wurden Zytokine und Chemokine, die Hämatopoese regulieren können, in der Milz gemessen. Wir konnten zeigen, dass MCMV Infektion das Auftreten von CFU-E und MkP in der Milz induziert, während sich deren Anzahl im Knochenmark nicht verändert. Die Anzahl und Proliferation von CFU-E in der Milz von Stat1ΔM/PMN Mäusen war vergleichbar zu Wurfgeschwistern (Stat1fl/fl Mäuse), was nahelegt, dass STAT1 in myeloiden Zellen im späteren Verlauf der Erythropoese, z.B. bei der Differenzierung von CFU-E zu Erythroblasten, eine Funktion hat oder das Überleben oder die Vermehrung der Erythroblasten unterstützt. Im Gegensatz dazu, beobachteten wir eine höhere Anzahl und leicht erhöhte Proliferation von MkP in der Milz von Stat1ΔM/PMN Mäusen. Obwohl weitere Experimente von Nöten sind, könnte dies darauf hinweisen, dass myeloide Zellen mittels STAT1 die Differenzierung von MkP in Megakaryozyten fördern. Zwischen Stat1ΔM/PMN und Stat1fl/fl Mäusen gab es keinen Unterschied in der Anzahl und Proliferation von MkP im Knochenmark. In der Milz fanden wir erhöhte Konzentrationen an Interleukin-6 (IL-6), Granulozyten-Makrophagen-Kolonie-stimulierenden Faktor (GM-CSF), IFNγ und Stammzellfaktor (SCF) und erniedrigte Konzentrationen an IL-11 in MCMV-infizierten Stat1ΔM/PMN Mäusen im Vergleich zu Kontrollen. Die Mengen an Erythropoetin (EPO), C-X-C-Motiv-Chemokin 12 (CXCL12), und Leukämiehemmendem Faktor (LIF) waren ähnlich in Milzen von Mäusen beider Gentoypen. Zusammenfassend zeigen unsere Daten, dass STAT1 in myeloiden Zellen EMH in der Milz auf verschiedenen Ebenen reguliert und dass EMH nicht einfach nur infektionsinduzierte Haematopoiese im Knochenmark widerspiegelt.Master thesis - University of Veterinary Medicine Vienna - 2022Extramedullary haematopoiesis (EMH) is the formation of blood cells outside the bone marrow. In adults, EMH compensates for an increased blood cell demand during infection and inflammation, in particular when bone marrow haematopoiesis in suppressed. Signal transducer and activator of transcription 1 (STAT1) is a key transcription factor used by all types of interferons (IFNs). We have shown previously that mice lacking STAT1 in myeloid cells (Stat1ΔM/PMN) have impaired EMH upon infection with murine cytomegalovirus (MCMV) and during sterile inflammation, as evidenced by lower numbers of erythroblasts and megakaryocytes in the spleen. To better understand the mechanism, we assessed the abundance and the proliferative state of their immediate precursors, the colony-forming unit erythroid (CFU-E) and megakaryocyte progenitors (MkP), in spleen and bone marrow at day 3 and day 5 post infection. In addition, we measured levels of cytokines and chemokines that are important in haematopoiesis in the spleen. We show that MCMV infection induces the appearance of CFU-E and MkP in spleens, whereas their frequencies in the bone marrow remains unchanged. The abundance and proliferative state of CFU-E was similar between Stat1ΔM/PMN mice and littermate controls (Stat1fl/flmice), indicating that STAT1 signaling in myeloid cells affects erythropoiesis at later developmental stages, such as the differentiation of CFU-E into erythroblasts or erythroblast proliferation/survival. In contrast, Stat1ΔM/PMN mice had an even higher frequency of splenic MkP than littermate controls, which was associated with a slightly increased proliferative rate. Albeit further studies are needed, this may indicate that myeloid cells promote the differentiation of MkP into megakaryocytes through STAT1-dependent mechanisms. In the bone marrow, the frequency and proliferative state of MkP was similar between Stat1ΔM/PMN and control mice. With respect to cytokines/chemokines, we found increased MCMV-induced upregulation of splenic interleukin-6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), IFNγ and stem cell factor (SCF) and increased downregulation of IL-11 in Stat1ΔM/PMN compared to control mice. Erythropoietin (EPO), C-X-C motif chemokine 12 (CXCL12) and leukemia inhibitory factor (LIF) levels were similar in mice of the two genotypes. Taken together, our data indicate that STAT1 in myeloid cell regulates splenic EMH at multiple levels and support the notion that EMH does not simply mirror haematopoietic responses in the bone marrow
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
The role of the STAT1ß isoform in CD4+ T cell differentiation
No full textBachelorarbeit - Veterinärmedizinische Universität Wien - 2020T-Lymphozyten sind ein wichtiger Bestandteil des adaptiven Immunsystems. Nach der Entwicklung und Reifung im Thymus wandern naive CD4+ T-Zellen in die Peripherie, um sich in sekundären lymphoiden Organen wie Lymphknoten und Milz anzusiedeln. Naive CD4+ T- Zellen werden über Signale von Antigen-präsentierenden Zellen und durch Zytokine, die die Differenzierung in bestimmte T-Helfer (TH) Zell-Untergruppen steuern, aktiviert. Der Janus Kinase (JAK)/ „signal transducer and activator of transcription” (STAT) Signalweg spielt eine wichtige Rolle bei der Polarisierung von CD4+ T-Zellen. STAT1 fungiert als Schlüsseltranskriptionsfaktor in der Interferon (IFN) - Signalübertragung. Bei Menschen und Mäusen existiert STAT1 in zwei Isoformen: STAT1α (volle Länge) und STAT1β (verkürzt). Ziel dieser Studie war es, den Einfluss von STAT1β auf die Differenzierung von TH-Zell- Untergruppen unter Verwendung von STAT1α-Isoform (Stat1α/α)- und Wildtyp (WT)-Mäusen zu untersuchen. Naive CD4+ T-Zellen wurden aus Milz und Lymphknoten von WT und Stat1α/α Mäusen isoliert und unter TH1-, TH17- oder nicht polarisierenden (TH0) Bedingungen differenziert. Die Menge an charakteristischen Transkriptionsfaktoren (T-bet und RORγt) und Zytokinen (IFN-γ und IL-17A) wurde mittels Durchflusszytometrie quantifiziert. Zusätzlich wurde totale RNA aus TH0- und TH1-Zellen isoliert und mittels RT-qPCR die Expression von Genen, die mit TH1- (Stat1, Ifng, Tbx21) TFH- (Bcl-6) oder cytotoxischen CD4+ T-Zellen (Gzmb, Prf1 und Crtam) assoziiert sind, bestimmt. Unsere Ergebnisse zeigen sowohl unter TH1- als auch unter TH0-Bedingungen einen Anstieg der IFN-γ-Produktion in Stat1α/α im Vergleich zu WT-Zellen, was auf eine erhöhte TH1-Differenzierung in Abwesenheit von STAT1β hinweist. Darüber hinaus fanden wir bei Aktivierung von Stat1α/α-CD4+ T-Zellen unter TH0-Bedingungen eine erhöhte Expression von Genen, die mit einem zytotoxischen Programm zusammenhängen, was darauf hindeutet, dass die Abwesenheit von STAT1β auch die Differenzierung von zytotoxischen CD4+ T-Zellen verstärkt. Im Gegensatz dazu führte das Fehlen von STAT1β führte bei Aktivierung unter TH17-polarisierenden Bedingungen auch zu einer beeinträchtigten Produktion von IL-17A. Zusammengefasst zeigen unsere Daten, dass das Fehlen von STAT1β das Gleichgewicht der Differenzierung von TH-Zellen beeinflusst, wodurch eine Zunahme von TH1-Zellen, CD4+ CTLs und möglicherweise TFH und eine Abnahme des TH17-Zellprogramms entsteht.Bachelor thesis - University of Veterinary Medicine Vienna - 2020T lymphocytes are an important part of the adaptive immune system. After development and maturation in the thymus, naïve CD4+ T cells migrate to the periphery to reside in secondary lymphoid organs, such as lymph nodes and spleen. Naïve CD4+ T cells are activated via signals from antigen-presenting cells (APCs) and exposure to cytokines, which direct their differentiation into certain T helper (TH) cell subsets. The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling pathway has a major role in the polarization of CD4+ T cells. STAT1 acts as a key transcriptional factor downstream of interferon (IFN) signalling. In humans and mice, STAT1 occurs in two isoforms: the full-length STAT1α and the truncated STAT1β. Aim of this study was to investigate the impact of STAT1β on the differentiation of TH cell subsets using mice that express only the STAT1α isoform (Stat1α/α mice) and wild-type (WT) mice. Naïve CD4+ T cells were isolated from spleen and lymph nodes of WT and Stat1α/α mice and differentiated under TH1-, TH17- or non-polarizing (TH0) conditions. The abundance of signature transcription factors (T-bet and RORγt) and cytokines (IFN-γ and IL-17A) was quantified using flow cytometry. In addition, total RNA was isolated from TH0 and TH1 cells and the expression of genes associated with TH1 (Stat1, Ifng, Tbx21) TFH (Bcl6) and cytotoxic CD4+ T cells (Gzmb, Prf1 and Crtam) was determined by RT-qPCR. Our results show an increase in IFN-γ production in both TH1 and TH0 conditions in Stat1α/α compared to WT cells, indicating increased TH1 differentiation in the absence of STAT1β. Moreover, we found an increased expression of genes related to a cytotoxic program upon activation of Stat1α/α CD4+ T cells under TH0 conditions, suggesting that STAT1β may also inhibit the differentiation of cytotoxic CD4+ T cells. The absence of STAT1β also resulted in an impaired production of IL-17A upon activation under TH17-polarising conditions. Collectively, our data suggest that the absence of STAT1β disbalances TH cell differentiation towards an increase in TH1 cells, CD4+ CTLs and possibly TFH, and a decrease in TH17 cell programs
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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