1,720,981 research outputs found
Exercise intolerance and fatigue in chronic heart failure: is there a role for group III/IV afferent feedback?
No full textExercise intolerance and early fatiguability are hallmark symptoms of chronic heart failure. While the malfunction of the heart is certainly the leading cause of chronic heart failure, the patho-physiological mechanisms of exercise intolerance in these patients are more complex, multifactorial and only partially understood. Some evidence points towards a potential role of an exaggerated afferent feedback from group III/IV muscle afferents in the genesis of these symptoms. Overactivity of feedback from these muscle afferents may cause exercise intolerance with a double action: by inducing cardiovascular dysregulation, by reducing motor output and by facilitating the development of central and peripheral fatigue during exercise. Importantly, physical inactivity appears to affect the progression of the syndrome negatively, while physical training can partially counteract this condition. In the present review, the role played by group III/IV afferent feedback in cardiovascular regulation during exercise and exercise-induced muscle fatigue of healthy people and their potential role in inducing exercise intolerance in chronic heart failure patients will be summarised
Transcranial Direct Current Stimulation over the Left Dorsolateral Prefrontal Cortex Improves Inhibitory Control and Endurance Performance in Healthy Individuals
No full textThe dorsolateral prefrontal cortex (DLPFC) is a crucial brain region for inhibitory control, an executive function essential for behavioral self-regulation. Recently, inhibitory control has been shown to be important for endurance performance. Improvement in inhibitory control was found following transcranial direct current stimulation (tDCS) applied over the left DLPFC (L-DLPFC). This study examined the effect tDCS on both an inhibitory control and endurance performance in a group of healthy individuals. Twelve participants received either real tDCS (Real-tDCS) or placebo tDCS (Sham-tDCS) in randomized order. The anodal electrode was placed over the L-DLPFC while the cathodal electrode was placed above Fp2. Stimulation lasted 30 min with current intensity set at 2 mA. A Stroop test was administered to assess inhibitory control. Heart rate (HR), ratings of perceived exertion (RPE), and leg muscle pain (PAIN) were monitored during the cycling time to exhaustion (TTE) test, while blood lactate accumulation (∆B[La−]) was measured at exhaustion. Stroop task performance was improved after Real-tDCS as demonstrated by a lower number of errors for incongruent stimuli (p = 0.012). TTE was significantly longer following Real-tDCS compared to Sham-tDCS (p = 0.029, 17 ± 8 vs 15 ± 8 min), with significantly lower HR (p = 0.002) and RPE (p < 0.001), while no significant difference was found for PAIN (p > 0.224). ∆B[La−] was significantly higher at exhaustion in Real-tDCS (p = 0.040). Our findings provide preliminary evidence that tDCS with the anodal electrode over the L-DLPFC can improve both inhibitory control and endurance cycling performance in healthy individuals
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
Ischemic preconditioning of the muscle reduces the metaboreflex response of the knee extensors
Full text linkPurpose: This study investigated the effect of ischemic preconditioning (IP) on metaboreflex activation following dynamic leg extension exercise in a group of healthy participants. Method: Seventeen healthy participants were recruited. IP and SHAM treatments (3 × 5 min cuff occlusion at 220 mmHg or 20 mmHg, respectively) were administered in a randomized order to the upper part of exercising leg’s thigh only. Muscle pain intensity (MP) and pain pressure threshold (PPT) were monitored while administrating IP and SHAM treatments. After 3 min of leg extension exercise at 70% of the maximal workload, a post-exercise muscle ischemia (PEMI) was performed to monitor the discharge group III/IV muscle afferents via metaboreflex activation. Hemodynamics were continuously recorded. MP was monitored during exercise and PEMI. Results: IP significantly reduced mean arterial pressure compared to SHAM during metaboreflex activation (mean ± SD, 109.52 ± 7.25 vs. 102.36 ± 7.89 mmHg) which was probably the consequence of a reduced end diastolic volume (mean ± SD, 113.09 ± 14.25 vs. 102.42 ± 9.38 ml). MP was significantly higher during the IP compared to SHAM treatment, while no significant differences in PPT were found. MP did not change during exercise, but it was significantly lower during the PEMI following IP (5.10 ± 1.29 vs. 4.00 ± 1.54). Conclusion: Our study demonstrated that IP reduces hemodynamic response during metaboreflex activation, while no effect on MP and PPT were found. The reduction in hemodynamic response was likely the consequence of a blunted venous return
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
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