1,721,003 research outputs found
REM sleep alterations in primary insomnia
No full textObjectives: We previously (2008) found an association between
REM sleep duration and perceived wakefulness in 81 patients with primary insomnia (PI) in addition to a clearly increased arousal index in REM sleep. The current study aimed to replicate and extend the previous findings.
Methods: Polysomnogram (PSG) and subjective sleep quality
questionnaire (Schlaffragebogen A, SFA) data of PI patients and
matched good sleeper controls (GSC) were evaluated for group
differences.
Results: One hundred and fifty-six new PI patients could be
matched to the same number of GSC (GSC; 60M, 96F; Mean age PI: 42.6 ± 12.4 years, GSC: 42.2 ± 13.4 years). PI patients had a higher wake time within bed time as well as lower REM and sleep stage 2 time. The association between perceived wake time and REM sleep time could be replicated in this new and larger group, as well as a clearly increased arousal index in REM sleep, while the arousal index in NREM sleep was significantly but less strongly increased.
Conclusion: We postulate that the psychophysiological hyperarousal characteristic for primary insomnia is particularly expressed as a REM sleep alteration. REM sleep appears to be particularly vulnerable to pre-sleep worries, leading to increased retrospective recall of this time as wake time and a lower restorative sleep quality
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
Brain reactivity to emotional stimuli in primary insomnia
No full textObjectives: Insomnia is highly comorbid with psychiatric disorders and, at least with respect to major depression, it has been found to be a clinical predictor. The psychobiological mechanisms, however, underlying this relationship are not yet fully understood. Heightened emotionality has been proposed to be a possible mediating factor. Supporting evidence refer to sleep deprivation studies and studies evaluating the role of sleep with respect to emotional memory. Moreover, studies on individuals exposed to chronic life stresses have shown that this condition is associated with sleep disturbances and increases the risk for emotional exhaustion. Neverthless, there is a surprising lack of studies evaluating emotion using physiological indeces in clinical samples of insomnia. Our main objective was to evaluate brain reactivity to emotional stimuli in patients with primary insomnia and in good sleepers. Methods: Patients with primary insomnia (n = 22) and healthy controls (n = 40) were presented with different blocks of neutral, negative, and sleep-related negative pictures during an fMRI task. Neutral and negative pictures were taken from the International Affective Picture System (IAPS), while sleep-related negative pictures were previously validated. Stimuli were matched for valence and arousal levels. All participants previously underwent two consecutive nights of polysomnographic recordings in order to exclude those with other sleep disorders. Results: Preliminary results are consistent with the hypothesis that people with insomnia present altered emotional responses in limbic areas to negative stimuli especially when related to the experience of the symptoms. Specifically, we found that patients with primary insomnia responded with increased amygdala activity to sleep-related negative stimuli as compared with good sleepers. Conclusion: People with insomnia might develop an emotional bias to stimuli related to sleep which would be associated to increasing rumination and preoccupation about the consequences of bad sleep. Clinical implications of the present findings, which need confirmation by further investigation, suggest that adding an emotional regulation component to standard therapy for insomnia might be effective to ameliorate sleep and to prevent the development of depression as a public health priority. The study 'Brain reactivity to emotional stimuli in primary insomnia' has received funding from the European Community’s Seventh Framework Programme (People, Marie Curie Actions, Intra-European Fellowship, FP7- PEOPLE-IEF-2008) under grant agreement n_ 235321
Sleep, depression, and insomnia: A vicious circle? (In press.)
No full textSleep, depression and insomnia have manifold associations. Psychiatric sleep research in affective disorders has demonstrated that sleep in depression is characterized by an impairment of sleep continuity, deficits in slow wave sleep and a disinhibition of REM sleep (including shortened REM latency and increased REM density). Traditionally, insomnia, i.e. prolonged latency to fall asleep and increased frequency of nocturnal wake periods, was considered as an unspecific symptom of affective disorders. In the meantime, a shift in clinical and scientific focus has taken place viewing insomnia in addition as an independent diagnostic entity and as a clinical predictor of depression. Unfortunately, the neurobiological processes underlying the relationships between sleep, insomnia and depression have not been fully identified yet. It is clear that both insomnia and depression are characterized by alterations in the arousal system in the CNS presenting as hyperarousal. Moreover, insomniac patients display reduced and fragmented REM sleep periods, which might interfere negatively with basal processes of emotion regulation. The alterations in the arousal system and the interaction of it with the affect-regulatory system over the course of time might influence cognitive systems and hence lead to the clinical picture of depression. Given the suggestion of insomnia symptoms as possibly involved in the causation and the maintenance of psychopathology in general, this type of sequence might also be found in relation to other mental disorders
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