1,721,048 research outputs found
Physical frailty and decline in general and specific cognitive abilities:The Lothian Birth Cohort 1936
Full text linkBackground: Physical frailty is associated with many adverse outcomes including disability, chronic disease, hospitalization, institutionalization and death. It is unclear what impact it might have on the rate of normal cognitive ageing. We investigated whether physical frailty was related to initial level of, and change in, cognitive abilities from age 70 to 79 years. Method: Participants were 950 members of the Lothian Birth Cohort 1936. Physical frailty was assessed at age 70 using the Fried criteria. Cognitive function was assessed at ages 70, 73, 76 and 79. We used linear regression to examine cross-sectional and prospective associations between physical frailty status at age 70 and factor score estimates for baseline level of and change in four cognitive domains (visuospatial ability, memory, processing speed, and crystallized ability) and in general cognitive ability.Results: Physical frailty, but not pre-frailty, was associated with lower baseline levels of visuospatial ability, memory, processing speed, and general cognitive ability after control for age, sex, education, depressive symptoms, smoking, and number of chronic illnesses. Physical frailty was associated with greater decline in each cognitive domain: age- and sex-adjusted standardized regression coefficients (95% confidence intervals) were: -0.45 (-0.70, -0.20) for visuospatial ability, -0.32 (-0.56, -0.07) for memory, -0.47 (-0.72, -0.22) for processing speed, -0.43 (-0.68, -0.18) for crystallized ability, and -0.45 (-0.70, -0.21) for general cognitive ability. These associations were only slighted attenuated after additional control for other covariates. Conclusion: Physical frailty may be an important indicator of age-related decline across multiple cognitive domains. <br/
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
Cognitive abilities in later life and the onset of physical frailty:The Lothian Birth Cohort 1936
Full text linkObjectives: To investigate whether poorer cognitive ability is a risk factor for the development of physical frailty, and whether this risk varies by cognitive domain. Design: Prospective longitudinal study with six-year follow-up.Setting: Edinburgh, Scotland.Participants: 594 members of the Lothian Birth Cohort 1936.Measurements: Frailty was assessed at ages 70 and 76 using the Fried criteria. Cognitive functions were assessed at ages 70, 73, and 76. Factor score estimates were derived for baseline level of and change in four cognitive domains: visuospatial ability, memory, processing speed, and crystallized cognitive ability. Results: Higher baseline levels of processing speed, memory, visuospatial ability and crystallized ability derived from ages 70, 73 and 76, and less decline in speed, memory and crystallized ability were associated with a reduced risk of becoming physically frail by age 76. When all cognitive domains were modelled together, processing speed was only domain associated with frailty risk: for a standard deviation increment in initial level of processing speed, the relative risk for frailty (RR) (95% confidence interval (CI)) was 0.53 (0.33, 0.85), after adjustment for age, sex, baseline frailty status, social class, depressive symptoms, number of chronic physical diseases, levels of inflammatory biomarkers, and other cognitive factor score estimates; for a SD increment in processing speed change (i.e. less decline) the RR (95% CI) was 0.26 (0.16, 0.42). When we conducted additional analyses using a single test of processing speed that did not require fast motor responses—Inspection Time—results were similar.Conclusions: The speed with which older people process information and the rate at which this declines over time may be an important indicator of the risk of physical frailty. <br/
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
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