1,720,959 research outputs found
Monitoring of extracellular substances after spontaneous and experimental subarachnoid hemorrhage
No full textEven though survival is considerably enhanced after surgical treatment of an aneurysmal subarachnoid hemorrhage (SAH), there is a critical period, which keeps the patient in intensive care for days or even weeks. Complications, such as vasospasm, ischemia and brain edema ultimately lead to further brain damage.The introduction of microdialysis allows regional monitoring of the cerebral extracellular fluid (ECF) for levels of metabolites and marker substances, which may predict development of various complications. However, the results are often difficult to interpret due to the heterogeneity of the patient groups. This thesis addresses the question of whether it is possible to follow courses of events after SAH by monitoring the cerebral ECF with respect to molecules of prognostic value. A model was developed for SAH (I), which compares the effects of blood and of increased ICP. The deleterious effects were mainly ascribed to blood in the subarachnoid fluid.Traumatic SAH (tSAH) is the most common type and is similar to spontaneous SAH with respect to secondary effects, such as vasospasm. Rotational acceleration of the head provides extensive tSAH (II). Glutamate and glycine increased in the hippocampal ECF in agreement with (I), but in addition, the trauma caused increased taurine and GABA. In contrast, aspartate, alanine and serine were less affected than after spontaneous SAH. Extensive neuronal loss occured in the tSAH model, both in the cerebral cortex, hippocampus and cerebellum, an effect interpreted to have a causal relationship with the high concentrations of excitatory amino acids in the ECF. A disadvantage of the tSAH model was the difficulty to distinguish effects of the hemorrhage and of the trauma per se.Seizures, caused by exposition of brain tissue to extravascular blood for a prolonged time, are common after SAH. Breakdown products of hemoglobin have been proposed as causes, paticularly after repeated bleedings. An obvious model for this question are cavernous angiomas (CA), a form of vascular malformations. The main symptoms are seizures, which often disappear upon the excision of the CA. Excised CAs from 10 patients were characterized biochemically (III). Iron and GFAP were markedly elevated in the angiomas as well as in the surrounding gliotic tissue. In the gliotic tissue, the concentrations of glycine and glutamine were increased, but that of GABA decreased.In two clinical studies with microdialysis sampling, SAH patients were operated with clip ligatures of ruptured arterial intracranial aneurysms. Neurotransmitter amino acids and other amino acids, as well as the glial marker protein GFAP were analyzed. The level of total amino acids in the ECF appeared to be higher in patients with low levels of consciousness (IV). Transient elevations of taurine and also of glycine and serine were more frequent than increases of the excitatory amino acids glutamate and aspartate (IV). The concentration of GFAP was higher in the ECF close to the site of the ruptured aneurysm. Specific changes in the concentrations of GFAP also coincided with events such as increased intracranial pressure (ICP), vasospasm and ischemia
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Monitoring of extracellular substances after spontaneous and experimental subarachnoid hemorrhage
No full textEven though survival is considerably enhanced after surgical treatment of an aneurysmal subarachnoid hemorrhage (SAH), there is a critical period, which keeps the patient in intensive care for days or even weeks. Complications, such as vasospasm, ischemia and brain edema ultimately lead to further brain damage.The introduction of microdialysis allows regional monitoring of the cerebral extracellular fluid (ECF) for levels of metabolites and marker substances, which may predict development of various complications. However, the results are often difficult to interpret due to the heterogeneity of the patient groups. This thesis addresses the question of whether it is possible to follow courses of events after SAH by monitoring the cerebral ECF with respect to molecules of prognostic value. A model was developed for SAH (I), which compares the effects of blood and of increased ICP. The deleterious effects were mainly ascribed to blood in the subarachnoid fluid.Traumatic SAH (tSAH) is the most common type and is similar to spontaneous SAH with respect to secondary effects, such as vasospasm. Rotational acceleration of the head provides extensive tSAH (II). Glutamate and glycine increased in the hippocampal ECF in agreement with (I), but in addition, the trauma caused increased taurine and GABA. In contrast, aspartate, alanine and serine were less affected than after spontaneous SAH. Extensive neuronal loss occured in the tSAH model, both in the cerebral cortex, hippocampus and cerebellum, an effect interpreted to have a causal relationship with the high concentrations of excitatory amino acids in the ECF. A disadvantage of the tSAH model was the difficulty to distinguish effects of the hemorrhage and of the trauma per se.Seizures, caused by exposition of brain tissue to extravascular blood for a prolonged time, are common after SAH. Breakdown products of hemoglobin have been proposed as causes, paticularly after repeated bleedings. An obvious model for this question are cavernous angiomas (CA), a form of vascular malformations. The main symptoms are seizures, which often disappear upon the excision of the CA. Excised CAs from 10 patients were characterized biochemically (III). Iron and GFAP were markedly elevated in the angiomas as well as in the surrounding gliotic tissue. In the gliotic tissue, the concentrations of glycine and glutamine were increased, but that of GABA decreased.In two clinical studies with microdialysis sampling, SAH patients were operated with clip ligatures of ruptured arterial intracranial aneurysms. Neurotransmitter amino acids and other amino acids, as well as the glial marker protein GFAP were analyzed. The level of total amino acids in the ECF appeared to be higher in patients with low levels of consciousness (IV). Transient elevations of taurine and also of glycine and serine were more frequent than increases of the excitatory amino acids glutamate and aspartate (IV). The concentration of GFAP was higher in the ECF close to the site of the ruptured aneurysm. Specific changes in the concentrations of GFAP also coincided with events such as increased intracranial pressure (ICP), vasospasm and ischemia
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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