1,721,116 research outputs found
Benzodiazepinen
No full textItem does not contain fulltextBenzodiazepines are the most popular and prescribed anxiolytics and hypnotics over the world. They are relatively safe and have a broad field of action. Benzodiazepines induce relaxation and sedation, reduce anxiety, facilitate sleep, cause muscle relaxation and have anti-convulsive effects. The biological profile of all benzodiazepine-derivatives is almost the same. A clear difference exists only in half-life, a measure for the time of action. Besides induction of sedation and sleepiness, benzodiazepines affect psychomotor functions as car-driving, give rise to anterograde amnesia and influence the EEG. When used for a longer time, tolerance may develop, efficacy decreases and dependence can be the result. Benzodiazepines relieve the symptoms of psychic problems, but do not cure the underlying problems. Nevertheless, they are of great value for patients in order to reduce anxiety and to promote sleep. Ideally, they should be used in supporting a causal therapy. Benzodiazepines mediate their effects by facilitating inhibitory processes in the brain; they act as GABA-agonists. Recently, the benzodiazepine-receptor was identified and new insights in the mechanisms of actions of the benzodiazepines indicate that more specific benzodiazepine-like drugs with less side-effects will be available in the future
Historie van het slaaponderzoek
No full textItem does not contain fulltextScientific research to sleep starts about hundred years ago. At that time technologies became available to record the electrical brain activity. The tiny electrical currents could be measured and written on paper with primitive amplifiers and galvanometers. Moreover, the stereotactic method to place electrodes adequately in every nucleus of the brain were developed. This allowed not only recordings of structures deep in the brain, but also electrical stimulation of these structures. In 1929 Hans Berger succeeded to transfer the animal EEG recordings of Caton and Beck, to humans. He described the alpha and beta waves. In 1935 the first classification of sleep-wake states became available. But with the discovery of the REM-sleep, the classification was revised by Rechtschaffen and Kales in 1968. This classification is still in general use. The concept of the reticular formation in the brainstem paved the way for new theoretical views. The active sleep theory replaced the old view in that sleep was merely a passive process. The association between REM-sleep and dreaming stimulated both research towards REM-sleep and dreaming. Recall of dreams showed that most dream content is a reflection of all day life. The mechanism of REM-sleep is thoroughly investigated, but its function still remains a mystery
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
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
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