1,721,152 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Emerging Neurological Infections in Brazil and Beyond
No full textChikungunya, Zika and dengue are types of arthropod-borne viruses (arboviruses). They have emerged in recent decades causing outbreaks of disease with global spread. Principally transmitted by an Aedes aegypti mosquito vector, infection mostly manifests as a fever-arthralgia-rash syndrome. However, a link between these viruses and neurological disease is becoming increasingly clear. Whilst it may be a relatively rare manifestation of infection, neurological involvement often results in severe consequences, causing disability and death. This is an important global public health concern.
These viruses co-circulate, and dual infection can occur. The spectrum of neurological manifestations linked to these viruses, and the importance of dual arbovirus infection are not fully understood. The research aimed to study i) the association between Zika, chikungunya, dengue and neurological disease in children and adults ii) the spectrum of neurological disease associated with infection iii) the clinical outcomes of patients with arbovirus-associated neurological disease in Brazil.
Initially, I studied adults with arboviral neurological disease in Pernambuco, Northeast Brazil, recruited during the 2015–16 Zika and chikungunya outbreaks. I subsequently conducted a multicentre case-control study in Brazil. The study ran between 2017-19, in the context of falling Zika case numbers nationally. However, there were chikungunya outbreaks in Rio de Janeiro and Pernambuco over this time. I investigated the arbovirus-positive cases from this study in more detail, with a descriptive analysis of clinical outcomes. Through this work, I modified and refined criteria to define the strength of an association between defined neurological syndromes and viral infection and proposed approaches to use of outcome measures. Responding to the emerging COVID-19 pandemic, I modified and applied these criteria to patients with COVID-19 and neurological presentations for use in a global individual patient data meta-analysis, this characterised clinical presentations and outcomes.
These findings advance current understanding and provide methodological approaches for clinical and epidemiological characterisation in the field of emerging and zoonotic infections
Variations on the Author
Full text link“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
Full text linkWe 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
Full text linkWe 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
Chemical and immunological characterisation of glycophospholipid and phospho-oligosaccharide from mycobacteria
Full text linkFollowing ligand binding by a wide variety of cytokines and growth factors, a glycosylphosphatidyl inositol phospholipase D (GPI-PLD) cleaves free membrane glycosylphosphatidyl inositol (GPI) to liberate water-soluble inositol phosphoglycan (IPG) second messengers. IPG are released outside cells and mediate many of the immediate metabolic effects of insulin. Many other cytokines and growth factors use IPG to signal, including IL-2, NGF, IGF-1 and ACTH. The composite structure of IPG molecules is known and they consist of hexose, hexosamine, inositol, phosphate and divalent cations. The development of clinical tuberculosis in a susceptible host appears to involve a highly complex interaction between the infecting organism and the host immune system, with much or indeed all the tissue damage characteristic of the disease being immune mediated. Many Mycobacterium tuberculosis colonised individuals do not develop active disease, and there are demonstrable immunological differences between the asymptomatic immune carrier state and the state of active disease in both humans and animal models. Mycobacterium tuberculosis contains PLD activity and contains phosphatidyl inositol linked glycans that could theoretically give rise to IPG like structures. Such glycolipids include lipoarabinomannan (LAM), lipomannan (LM) and phosphoinositol mannoside (PIM). Previously it has been shown in our laboratory and that of our collaborators that two strains of the pathogen M. tuberculosis and a non-pathogen, M. vaccae, contain IPG- like biological activity. This mycobacteria derived material has been provisionally named phospho-oligosaccharide (POS). The aim of this study was to examine the hypothesis that mycobacteria may contain a homologous system to the mammalian GPI/IPG signalling mechanism. Using an established protocol for the purification of mammalian GPI a glycophospholipid (GPL) was isolated from M. tuberculosis and M. vaccae that showed similar characteristics to mammalian GPI. This GPL was a substrate for (glycosyl) phosphatidylinositol phospholipase C (GPI-PLC), contained phosphate, sugar residues and did not contain amino groups. GPL was biologically active in a cell free pyruvate dehydrogenase (PDH) phosphatase activation assay and induced inflammatory mediator release from monocyte/macrophage cells. GPL is distinct from LAM, LM and PIM because it was sensitive to GPI-PLC and incorporated radioactive galactose. POS fractions were isolated from mycobacteria that were biologically active in PDH phosphatase, lipogenesis, cell proliferation and nitric oxide production assays, contained carbohydrate, phosphate (except for one fraction) and amino groups. On the basis of amino group analysis, which revealed that POS contained amino groups and GPL did not, POS is not a cleavage product of mycobacterial GPL, as is the case with GPI and IPG in mammalian cells. However, there were interesting similarities in biological activity between GPL and POS. Serological studies were undertaken to characterise mycobacterial POS both structurally and immunologically. Although POS exhibit biological activity in systems where mammalian IPG are also active, there are clearly structural differences between POS and IPG because some antibodies that bind IPG do not bind POS. POS are immunogenic: administration of complete Freund's adjuvant induced an anti-POS antibody response in rabbits (but not in mice) and sera from tuberculosis patients contained significantly higher levels of anti-POS antibody than healthy controls. POS is proliferogenic for human peripheral blood mononuclear cells in vitro, in particular, POS activates human B cells in vitro causing a greater increase in B cell CD25 expression than T cell CD25 expression. Thus the material described has some interesting immunological properties, although its role in the pathogenesis of tuberculosis remains to be determined. The growth factors IL-2 and insulin have both been shown to signal using IPG cleaved from GPI, it is therefore intriguing that mycobacteria appear to contain a homologue of an immunologically relevant mammalian second messenger
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