1,721,067 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
Genetic association studies in stroke
No full textStroke is the third most common cause of death and the most common cause of disability in adults in developed countries. It is a complex disease in which genetic and environmental factors make about equal contributions. A significant proportion of the environmental component remains to be elucidated and little is known about which genes that are involved. There are two main stroke types; ischemic and hemorrhagic. Both these types have several different etiological subtypes.
The specific aim of the present work was to perform clinical association studies to test the hypothesis that hemostatic and inflammatory gene polymorphisms, and/or plasma levels of the respective proteins, are associated with stroke, and to investigate whether associations differ between stroke subtypes.
The studies on ischemic stroke were based on the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), in which great emphasize has been put on phenotyping by physical examination and neuroimaging. The study comprises 600 consecutive ischemic stroke patients presenting with ischemic stroke before the age of 70 years and 600 matched population-based controls. Stroke patients were classified according to the main etiological subtypes of ischemic stroke, i.e. large-vessel disease (LVD), small-vessel disease (SVD), cardioembolic stroke (CE stroke) and cryptogenic stroke. The study on aneurysmal subarachnoid hemorrhage (aSAH) was based on patients admitted to the Neurointensive Care Unit, Sahlgrenska. A total of 183 patients with a confirmed aneurysmal origin of the SAH were included. Two matched population-based controls were recruited for each case. Genotyping was performed using 5´nuclease assays (TaqMan) and plasma levels of proteins were determined by immunological methods.
Family history of stroke showed independent association to all ischemic stroke subtypes, except CE stroke. In our first genetic association study, the fibrinolytic pathway was studied. A reduced risk of ischemic stroke was observed for a genotype combination indicating a high gene expression level of both tissue-type plasminogen activator and plasminogen activator inhibitor type 1. This association was not detected in aSAH. However, an increased risk of aSAH was found for subjects carrying the coagulation factor XIII 34Leu allele. This variant has been shown to influence fibrinolysis by affecting the fibrin network. Family history of myocardial infarction (MI) only showed association to one ischemic stroke subtype, i.e. LVD. The explanation for this may be that atherosclerosis is a common denominator for MI and LVD. In support for this hypothesis, increased plasma levels of the inflammatory marker C-reactive protein was only found in the LVD group. This is in contrast to the fibrinolytic pathway. Plasma levels of tPA, PAI-1 and the fibrinolytic inhibitor TAFI were increased in all ischemic stroke subtypes.
In conclusion, the results support a genetic contribution in stroke. This genetic contribution seems to differ between subtypes, which highlights the importance of subtype classification in stroke research. Furthermore, the findings suggest that inflammatory factors may be of more importance for developing LVD, while the fibrinolytic pathway seems to be involved in all ischemic stroke subtypes
Genetic association studies in stroke
No full textStroke is the third most common cause of death and the most common cause of disability in adults in developed countries. It is a complex disease in which genetic and environmental factors make about equal contributions. A significant proportion of the environmental component remains to be elucidated and little is known about which genes that are involved. There are two main stroke types; ischemic and hemorrhagic. Both these types have several different etiological subtypes. The specific aim of the present work was to perform clinical association studies to test the hypothesis that hemostatic and inflammatory gene polymorphisms, and/or plasma levels of the respective proteins, are associated with stroke, and to investigate whether associations differ between stroke subtypes. The studies on ischemic stroke were based on the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), in which great emphasize has been put on phenotyping by physical examination and neuroimaging. The study comprises 600 consecutive ischemic stroke patients presenting with ischemic stroke before the age of 70 years and 600 matched population-based controls. Stroke patients were classified according to the main etiological subtypes of ischemic stroke, i.e. large-vessel disease (LVD), small-vessel disease (SVD), cardioembolic stroke (CE stroke) and cryptogenic stroke. The study on aneurysmal subarachnoid hemorrhage (aSAH) was based on patients admitted to the Neurointensive Care Unit, Sahlgrenska. A total of 183 patients with a confirmed aneurysmal origin of the SAH were included. Two matched population-based controls were recruited for each case. Genotyping was performed using 5´nuclease assays (TaqMan) and plasma levels of proteins were determined by immunological methods. Family history of stroke showed independent association to all ischemic stroke subtypes, except CE stroke. In our first genetic association study, the fibrinolytic pathway was studied. A reduced risk of ischemic stroke was observed for a genotype combination indicating a high gene expression level of both tissue-type plasminogen activator and plasminogen activator inhibitor type 1. This association was not detected in aSAH. However, an increased risk of aSAH was found for subjects carrying the coagulation factor XIII 34Leu allele. This variant has been shown to influence fibrinolysis by affecting the fibrin network. Family history of myocardial infarction (MI) only showed association to one ischemic stroke subtype, i.e. LVD. The explanation for this may be that atherosclerosis is a common denominator for MI and LVD. In support for this hypothesis, increased plasma levels of the inflammatory marker C-reactive protein was only found in the LVD group. This is in contrast to the fibrinolytic pathway. Plasma levels of tPA, PAI-1 and the fibrinolytic inhibitor TAFI were increased in all ischemic stroke subtypes. In conclusion, the results support a genetic contribution in stroke. This genetic contribution seems to differ between subtypes, which highlights the importance of subtype classification in stroke research. Furthermore, the findings suggest that inflammatory factors may be of more importance for developing LVD, while the fibrinolytic pathway seems to be involved in all ischemic stroke subtypes
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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