1,721,206 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
Genetic mediation of the link between schizophrenia and cannabis use
No full textCannabis use is likely to increase the risk for schizophrenia, but it is neither a necessary nor a sufficient cause. Genetic factors may mediate the link between cannabis and schizophrenia. Research has recently started to explore interactions and correlations between genes, cannabis, and psychosis. Results from studies using indirect measures of genetic liability to psychotic disorder suggest that the psychotogenic effect of cannabis is greater in individuals with a predisposition for psychosis than in those without such a predisposition (gene-environment interaction) and that predisposition for psychosis is correlated with cannabis use (gene-environment correlation). The few studies that have investigated genetic polymorphisms directly found no evidence of correlation between cannabis use and genetic characteristics, and are inconclusive with regard to gene-environment interaction. One study reported an interaction effect between cannabis use and the Val158MET polymorphism of the catechol-O-methyltransferase (COMT) gene on the development of schizophrenia, another study did not replicate these findings, and yet another found this interaction only in individuals who already had a high predisposition for psychosis but not in those with no predisposition for psychosis. Thus, although it is likely that interactions between genes and cannabis influence the development of schizophrenia, further work is necessary to identify which genetic variations are involved and how these interact with cannabis. The inclusion of higher-order gene-gene and gene-environment interactions may be needed to understand the complex relationship between cannabis and schizophrenia. © 2008 Elsevier Ltd. All rights reserved
Age at migration and psychotic-like experiences: Clues in childhood to explain the increased risk for psychosis among ethnic minorities
No full textThe risk for psychotic disorders is increased among immigrants compared to native populations in several countries around the world. The exact nature of this environmental exposure remains unclear. In order to find an explanation for the excess risk, it is crucial to determine the relevant timing of exposure. Most research studied the period of onset of the disorder, but research should extend to early childhood and adolescence. Methods: Two studies were conducted. A 7-year first-contact incidence study identified and diagnosed all individuals aged 15-54with a first episode of psychosis in The Hague (N=618), and investigated the effect of age at the time of migration on the incidence of psychotic disorders among immigrants A comprehensive municipal registration system provided the denominator, including information on ethnicity and age at migration to the Netherlands. The second study assessed prevalence and correlates of psychotic-like experiences (PLEs) in a multi-ethnic cohort of 10-16 year-old schoolchildren (N=1563), using self-reportmeasures. Psychotic-like experiences were measured with 7 items from the Kiddie-Schedule for Affective Disorders and Schizophrenia. Additional questions explored frequency of the experiences, associated distress and cultural familiarity with the experiences. Emotional and behavioral problems were measured with the Strengths and Difficulties Questionnaire and the Social and Health Assessment. Results: Lower age at migration was associated with a higher incidence of psychotic disorders in immigrants. People who migrated between 0-4 years had the most elevated risk for psychotic disorders compared to Dutch (age- and sex-adjusted IRR= 2.96; 95% CI, 2.10-4.17) and the risk gradually decreased with older age at migration: adjusted IRR= 2.31 (1.61-3.29), 1.51 (1.02-2.25) to 1.00 (0.58-1.72) for age at migration categories 5-9, 10-14 and >29 respectively. Ethnic minority youth reported a higher rate of psychotic-like experiences with high impact (that is, high frequency or strong influence on their life) than Dutch youth (8.4% and 3.1% respectively, OR 2.8; 95% 1.7-4.6).Moroccan and Turkish youth more often knew a healthy person in their family or culture who had the same experiences, but after adjustment for this “cultural context”, differences with native Dutch youth in the impact of psychotic-like experiences remained substantial and statistically significant. Psychotic-like experiences were strongly correlated with emotional and behavioral problems. Conclusions: The adverse influence of migration on the risk of psychotic disorders is most prominent in early life. Psychotic-like experiences with high impact are more common in ethnic minority youth than in Dutch youth. These findings suggest that early childhood is the critical period for developing an increased vulnerability for psychotic disorders among immigrants, and that early, subclinical expression of this vulnerability can already be found in (pre-)adolescents from ethnic minority groups
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
Psychotic-Like Experiences and cumulative social disadvantage in a multi-ethnic population-based adolescent sample
No full textBackground: Adverse social circumstances in childhood and adolescence increase vulnerability for adult psychotic disorders. Children who have psychotic- like experiences (PLEs) are at higher risk to develop psychotic disorders later in life. If PLEs are considered potential precursors of psychotic disorders and the risk for psychotic disorders develops in early life, PLEs in childhood should be related to indicators of social disadvantage. Methods: A self-report study assessing a sample of 1545 schoolchildren (45% Dutch, 26% Moroccan, 11% Turkish, 5% Western and 13% other non-Western) was conducted in the Netherlands (age range: 9-16). PLEs were measured with 8 items from the psychosis section of the K-SADS. Additional questions addressed impact of the PLEs. Measures of parental socio-economic status, neighborhood deprivation, perceived discrimination, parental separation, housing stability and degree of urbanization were used as indicators of social disadvantage, based on which a cumulative index of social disadvantage was created (low, medium, high). Results: The overall prevalence of any PLE with high impact was 6% (N = 93). Neighborhood deprivation, perceived discrimination and an unstable housing situation were associated with risk for PLEs. Age- and sex-adjusted Odds Ratios for any PLE with high impact were 1.83 (95% CI, 0.92-3.69) for medium and 2.28 (1.11-4.69) for high cumulative social disadvantage, compared to low social disadvantage. The risk was higher for ethnic minority youth compared to Dutch (Odds Ratio = 2.6; 95% CI, 1.6-4.3). The increased risk remained after adjusting for social disadvantage. Conclusion: The risk for PLEs with high impact was associated with indicators of social disadvantage. PLEs with high impact were more prevalent in ethnic minority youth than in Dutch youth. The increased risk was not explained by cumulative social disadvantage
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