1,721,904 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
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
Peripheral infection evokes exaggerated sickness behaviour in pre-clinical murine prion disease
No full textPeripheral infections in mammals are characterised by local, systemic and CNS effects. The latter give rise to sickness behaviour. Pro-inflammatory cytokines such as interleukin-1? (IL-1?) are thought to be important mediators of this neuro-immune signalling (Cartmell et al., 1999). There is anecdotal evidence suggesting that peripheral infections in patients with Alzheimer’s disease have more severe behavioural consequences than those in otherwise healthy elderly subjects, and it is well known that brain microglia are activated in the elderly and in Alzheimer’s disease ( McGeer et al., 1987). Using ME7-induced murine prion disease as a model of chronic neurodegeneration that displays chronic microglial activation, and the intra-peritoneal injection of bacterial lipopolysaccharide to mimic a peripheral infection, we have shown that the temperature and activity responses of animals with pre-clinical prion disease were exaggerated compared with controls, and that this was associated with a significant increase in brain levels of IL-1?. We hypothesise that prior priming of microglia by the degenerative process, followed by further activation through signalling from the periphery, resulted in increased brain IL-1? synthesis and the consequent acute sickness behavioural responses.These findings demonstrate an interaction between peripheral infection and pre-existing CNS inflammation and suggest that further stimulation of an already primed microglial population by a peripheral infection may drive disease progression in chronic inflammatory conditions such as Alzheimer’s disease and prion disease
Interaction between systemic inflammation and brain inflammation in chronic neurodegeneration
No full textSystemic inflammation, evoked by an infection or injury leads to the production of inflammatory mediators that communicate with the brain. This communication route involves further synthesis of inflammatory mediators in the brain, and this leads in turn to changes in metabolism and behaviour. There is evidence to show that resident cells of mononuclear phagocyte lineage are key players in this process. In an animal model of chronic neurodegeneration, murine prion disease, we have shown that there is an atypical inflammatory response dominated by the presence of activated perivascular macrophages and microglia. These cells synthesise minimal levels of proinflammatory cytokines. However, following asystemic inflammatory challenge mice with prion disease were challenged with endotoxin (LPS) or poly IC to mimic a systemic bacterial or viral infection. Following challenge, the mice with prion disease showed exaggerated sickness behaviour. This exaggerated sickness behaviour was associated with a dramatic switch in the cytokine profile in the brain from an anti-inflammatory to a proinflammatory profile. This switch in cytokine profile was also accompanied by an increase in the number of neurons undergoing apoptosis in the brains of animals with prion disease. These data lead to the hypothesis that systemic inflammation may affect both symptoms of chronic neurodegenerative disease and disease progression. Ongoing clinical studies in patients with Alzheimer’s disease support this hypothesis
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
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