1,721,048 research outputs found
More Homology Flows
No full textFlows and cuts have been the topic of much study since Ford and Fulkerson's
original paper. The problem we look at is the computation of flows on some
generalizations of planar graphs. In particular, the input graph can be embedded
on a surface of genus g, and has the source and sink on the same face. We show
this problem can be reduced to a convex programming problem in dimension
2g, and also show some interesting properties of the feasible polytope.not peer reviewedSubmitted by Aparna Sundar ([email protected]) on 2010-02-12T13:54:10Z
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Previous issue date: 2010-02-12unpublishe
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
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
The α-Adrenergic System and CaMKII in Diabetic Heart Disease
Full text linkThe relationship between diabetes mellitus and heart disease is widely documented, with heart disease being the main cause of mortality in diabetic patients. Diabetes impairs the autonomic nervous system, leading to an imbalance between parasympathetic and sympathetic nervous output. Alterations in autonomic cardiac balance in diabetes may lead to fatal arrhythmias and impairments in contractility. Calcium/calmodulin-dependent protein kinase II (CaMKII) is a key regulator of cardiac contractility and is overactive in diabetes mellitus. CaMKII inhibition in diabetic models reduces both arrhythmogenic events and impaired cardiac contractility. Our laboratory has previously implicated CaMKII in the α-adrenergic cascade, although the role of both in diabetes-induced cardiac dysfunction is unclear. I hypothesised that CaMKII and the α-adrenergic system are dysregulated in diabetes, which may underlie arrhythmogenesis and impaired contractility in diabetic patients.
Trabeculae from human right atrial appendage tissue were superfused with either methoxamine (an α-adrenergic agonist) or KN93 (a CaMKII inhibitor) followed by the two in conjunction. Changes in contractility and spontaneous contractions in the atrial samples were measured. CaMKII inhibition with KN93 consistently reduced the contractile function of the non-diabetic trabeculae and prevented a positive inotropic effect from methoxamine administration. This was consistent with previous work implicating CaMKII in the α-adrenergic cascade in mouse models. All samples showed no increase in arrhythmic events with methoxamine administration. We did not observe significant differences in the contractile response of diabetic and non-diabetic tissue with methoxamine administration. Diabetic tissue responded with an increase in developed force with addition of methoxamine and KN93, as opposed to non-diabetic tissue which showed a decrease in developed force. An equal proportion of both diabetic and non-diabetic samples showed a significant negative inotropic effect in response to methoxamine when compared with positive responders to the drug. The inotropic response to methoxamine seems to correlate with the duration of diabetes in diabetic patients, although some other factor may be influencing the non-diabetic negative inotropic response.
This study is the first to implicate CaMKII in the α-adrenergic cascade in human cardiac tissue. The response to α-adrenergic stimulation seems to be dependent on a factor independent to diabetes, as similar proportions of negative responders to the drug were present in both non-diabetic and diabetic populations. The correlation of the blunted inotropic response to methoxamine with diabetes duration may be impacted by progressive denervation occurring in late stage diabetics, resulting in impaired responses to α-adrenergic agonists. The implication of CaMKII in the α-adrenergic cascade contraindicates the use of α-adrenergic agonists in conditions where overactive CaMKII may be pathological, such as diabetes
The α-Adrenergic System and CaMKII in Diabetic Heart Disease
No full textThe relationship between diabetes mellitus and heart disease is widely documented, with heart disease being the main cause of mortality in diabetic patients. Diabetes impairs the autonomic nervous system, leading to an imbalance between parasympathetic and sympathetic nervous output. Alterations in autonomic cardiac balance in diabetes may lead to fatal arrhythmias and impairments in contractility. Calcium/calmodulin-dependent protein kinase II (CaMKII) is a key regulator of cardiac contractility and is overactive in diabetes mellitus. CaMKII inhibition in diabetic models reduces both arrhythmogenic events and impaired cardiac contractility. Our laboratory has previously implicated CaMKII in the α-adrenergic cascade, although the role of both in diabetes-induced cardiac dysfunction is unclear. I hypothesised that CaMKII and the α-adrenergic system are dysregulated in diabetes, which may underlie arrhythmogenesis and impaired contractility in diabetic patients.
Trabeculae from human right atrial appendage tissue were superfused with either methoxamine (an α-adrenergic agonist) or KN93 (a CaMKII inhibitor) followed by the two in conjunction. Changes in contractility and spontaneous contractions in the atrial samples were measured. CaMKII inhibition with KN93 consistently reduced the contractile function of the non-diabetic trabeculae and prevented a positive inotropic effect from methoxamine administration. This was consistent with previous work implicating CaMKII in the α-adrenergic cascade in mouse models. All samples showed no increase in arrhythmic events with methoxamine administration. We did not observe significant differences in the contractile response of diabetic and non-diabetic tissue with methoxamine administration. Diabetic tissue responded with an increase in developed force with addition of methoxamine and KN93, as opposed to non-diabetic tissue which showed a decrease in developed force. An equal proportion of both diabetic and non-diabetic samples showed a significant negative inotropic effect in response to methoxamine when compared with positive responders to the drug. The inotropic response to methoxamine seems to correlate with the duration of diabetes in diabetic patients, although some other factor may be influencing the non-diabetic negative inotropic response.
This study is the first to implicate CaMKII in the α-adrenergic cascade in human cardiac tissue. The response to α-adrenergic stimulation seems to be dependent on a factor independent to diabetes, as similar proportions of negative responders to the drug were present in both non-diabetic and diabetic populations. The correlation of the blunted inotropic response to methoxamine with diabetes duration may be impacted by progressive denervation occurring in late stage diabetics, resulting in impaired responses to α-adrenergic agonists. The implication of CaMKII in the α-adrenergic cascade contraindicates the use of α-adrenergic agonists in conditions where overactive CaMKII may be pathological, such as diabetes
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