1,720,984 research outputs found
Effects of creatine on swimming velocity, body composition and hydrodynamic variables
No full textAim. Creatine supplementation (CS) has been reported to increase body weight and improve performance during high intensity, short duration, exercise tasks. However, none of the published studies has investigated the influence of CS on performance related hydrodynamic variables during swimming. To investigate the effect of oral CS on swimming velocity, body composition and hydrodynamic variables during the period of final preparation of competitive junior female swimmers. Methods. In a double blind and randomized manner, 16 female swimmers, were supplemented with 20 g day-1 of creatine monohydrate (CS group), or a maltodextrin placebo (PL group) for 21 days. Just pre- and post-21 days of supplementation, subjects performed 2×25 swimming bouts at maximum velocity with a 3 min recovery between bouts. The variables measured were 25 m swimming velocity (MSV25); active drag force CDf); hydrodynamic coefficient (Cx); power output (Po). Body measures were also analysed: body weight (kg), fat-mass (% FAT), body water (% H2O), and fat free mass (FFM). Results. Significant differences were observed in hydrodynamic values: the CS group showed a significant reduction (25%), in Df, Cx and Po values, when comparing pretest with post-test. No differences were found in variables related to body composition and performance between CS group and PL group, as well as for CS group during the experimental period. Conclusion. These data suggest that 21 days of CS produced significant effects on gross and/or propelling efficiency during swimming in female athletes. However, CS did not influence performance, body weight and body composition
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
Physiological determinants of performance in breaststroke swimming events
No full textBackground: The comprehension of the relationships between physiological parameters and swimming performance in Breaststroke events seems not to be fully understood. Research question: The aim of this study was to correlate aerobic and anaerobic physiological measurements with the performance in 100m and 200m breaststroke. This performance was determined either with the subjects' performance in 100m and 200m simulated breaststroke events with the Aquatrainer valve and with the subjects' season best performance in true competitions. Methods: Twenty two male swimmers involved in systematic training and competition programmes participated in this study. The swimmers were divided in two groups (10 for 100m group and 12 for 200m group). The swimmers' personal best performance for the 100m and the 200m breaststroke was converted according to the FINA table. The subjects performed a graded swimming test and an all-out test on different days. Throughout all testing expired gases were collected breath by breath and analysed with a K4b2 Gas Analyser connected to an AquaTrainer Valve to determine different physiological parameters. Capillary blood samples were also collected from the finger to determine the blood lactate concentration after each boot. The subjects' performance during the all-out tests was taken as dependent variable and the physiological measures were defined as independent variables. Results: The performance during the all-out bout correlated with the season best FINA score (r = 0.52; p<0.05). The best season performance was more accurately predicted by the combination of aerobic fraction of energy release, peak blood lactate post-exercise and VO(2) elicited at the swimming velocity corresponding to the 2mmol.L(-1) threshold for the 200m event (imprecision approximate to 5%), while in the 100m event it was best predicted by the combination of estimated body fat, VO(2) elicited at the swimming velocity corresponding to the 4mmol.L(-1) threshold and peak VO(2) (imprecision approximate to 3%). Conclusions: Physiological testing with direct VO(2) measurement and blood lactate assessment may provide some insights into the performance ability of breaststroke swimmers, namely by the assessment of peak VO(2) and both sub-maximal and supra-maximal blood lactate
Slow component of VO2 during level and uphill treadmill running: relationship to aerobic fitness in endurance runners
No full textAim. The aim of this study was to compare the oxygen uptake (V̇O 2) slow component (SC) during level and uphill running in endurance runners, and to identify associations between the SC and the following aerobic fitness indicators: peak V̇O2, running speed associated with the peak V̇O2 (Vpeak), running speed at the lactic threshold and the V̇O2 fraction elicited at the lactic threshold. Methods. Fourteen male endurance-trained runners underwent several 6-min bouts of level (LTR) and 10.5% uphill treadmill running. V̇O2 SC was calculated as the difference between mean V̇O2 during the 6th and the 3rd minutes. Results. The highest mean values for the SC were 181.9±240.2 mL·mur-1 for level running at ∼94% peak V̇O2 and 105.4±154.6 mL·min-1 for uphill running at ∼90% peak V̇O2. The SC observed during the last bout of the LTR correlated with peak V̇O2 and with Vpeak (-0.71 and -0.76, P<0.05, respectively). Conclusion. The results show that for endurance-trained runners the magnitude of the SC is not affected by the treadmill gradient and that within a homogeneous sample of endurancetrained runners the SC does not correlate with indicators of aerobic fitness
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
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