Time spent on new songs: word-of-mouth and price effects on teenager consumption     

Noémi Berlin  Anna Bernard  Guillaume Fürst 《Journal of Cultural Economics》2015,39(2):205-218

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Polarography     

V.?LakshminarayananEmail author 《Resonance》2004,9(9):51-61

J Heyrovsky’s invention of polarography in which a dropping mercury electrode is used in the electrochemical cell revolutionised electroanalysis, study of electrode kinetics and adsorption studies on mercury electrodes. Polarography has also directly contributed to the development of new and innovative ideas in electrochemical techniques, instrumentation and applications  相似文献   

EDITORS' PREFACE   总被引：1，自引：0，他引：1  

W. Andrew Collins  Willis F. Overton 《Monographs of the Society for Research in Child Development》2006,71(3):vii-ix

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‘Fractured communities’: uncertainty,stress, and (a lack of) communal coping in Palestinian refugee camps     

Tamara D. Afifi  Walid A. Afifi  Anne F. Merrill  Najib Nimah 《Journal of Applied Communication Research》2016,44(4):343-361

This study examined how communal coping reveals itself in Palestinian refugee camps and the conditions that promote or prevent its occurrence. Individual and dyadic interviews were conducted with 40 mothers and one of their adolescent children living in Palestinian refugee camps in Lebanon. The results revealed that communal coping existed within the mother–adolescent dyad to a certain extent, but was rare within the larger context of the refugee camps. While families and neighbors did not typically verbalize their hardships and actively cope with them as a group, there was often an implicit recognition that they were all experiencing the same uncertainty and stress. Acting upon their uncertainty as a collective, however, was greatly hampered by mistrust within and outside the camps, due to widespread violence, privacy violations, vying for scarce resources, and disloyalty. Parents and adolescents also engaged in protective buffering whereby they attempted to reduce the stress of the family by keeping stress and fears to themselves rather than communicating about them. Even though protective buffering helped the refugees cope with chronic uncertainty and maintain a sense of normalcy, it prevented them from acting upon the problem as a group. Finally, parents emphasized that the child’s education provided hope for the future. Practical implications are discussed.  相似文献   

A plausible case for a science–religion conflict thesis     

Maurice?A.?FinocchiaroEmail author 《Metascience》2016,25(3):405-408

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Self-reported symptoms and risk factors for digital ischaemia among international world-class beach volleyball players     

Daan Van De Pol  Sena Alaeikhanehshir  Mario Maas  P. Paul F.M. Kuijer 《Journal of sports sciences》2016,34(12):1141-1147

The prevalence of ischaemia-related symptoms is remarkably high among elite indoor volleyball players. Since the exposure to sport-specific demands may be higher in beach volleyball compared to indoor volleyball, the aim of this study was to assess the prevalence of ischaemia-related symptoms and associated risk factors among world-class beach volleyball players. Therefore, a questionnaire survey was performed among beach volleyball players active during the 2013 Grand Slam Beach Volleyball in the Netherlands. In total, 60 of the 128 beach volleyball players (47%) participated: 26 males and 34 females from 17 countries. The self-reported prevalence of cold or blue or pale digits in the dominant hand during or immediately after practice or competition was 38% (n = 23). Two risk factors were independently associated with symptoms of blue or pale digits: more than 14 years playing volleyball (odds ratio (OR) 4.42, 90% confidence interval (90% CI) 1.30–15.07) and sex (female) (OR 4.62, 90% CI 1.15–18.57). In conclusion, the prevalence of symptoms associated with digital ischaemia is high among international world-class beach volleyball players. Female sex and the length of the volleyball career were independently associated with an increased risk of ischaemia-related symptoms. The high prevalence of these seemingly innocuous symptoms and possible associated risk factors warrant regular monitoring since early detection can potentially prevent thromboembolic complications and irreversible tissue damage.  相似文献   

Do karate fighters use situational probability information to improve decision-making performance during on-mat tasks?     

Nicolas Milazzo  Damian Farrow  Alexis Ruffault  Jean F. Fournier 《Journal of sports sciences》2016,34(16):1547-1556

This study examined the contribution of situational probability information to the perceptual and cognitive processes underlying decision-making behaviour during in situ Karate performance. Experts and novices were required to make decisions about various attacks in different fight scenarios. The order in which the fight situations were presented was modified in order to provide advanced probability information and identify whether fighters were able to use the latter information to make better decisions. Specifically, one of the attacks was repeated every four actions. Results revealed that experts were more accurate and faster than their less skilled counterparts to block and counterattack the opponent. The experts picked up the occurrence of the attack pattern after the fifth repetition whereas novices did not. This enabled experts to improve decision time and decision accuracy. Findings suggest that such superiority could stem from the perceptual and cognitive skills possessed by the experts, thus giving them the opportunity to recognise a situation more easily. This was reinforced by gaze behaviour which demonstrated that experts used a more efficient search strategy involving fewer fixations of longer duration on a lesser number of areas relative to the novices. Moreover, experts generated more refined karate-specific knowledge structures compared with the novices.  相似文献   

Mediating effects of resistance training skill competency on health-related fitness and physical activity: the ATLAS cluster randomised controlled trial     

Jordan J. Smith  Philip J. Morgan  Ronald C. Plotnikoff  David F. Stodden  David R. Lubans 《Journal of sports sciences》2016,34(8):772-779

The purpose of this study was to examine the mediating effect of resistance training skill competency on percentage of body fat, muscular fitness and physical activity among a sample of adolescent boys participating in a school-based obesity prevention intervention. Participants were 361 adolescent boys taking part in the Active Teen Leaders Avoiding Screen-time (ATLAS) cluster randomised controlled trial: a school-based program targeting the health behaviours of economically disadvantaged adolescent males considered “at-risk” of obesity. Body fat percentage (bioelectrical impedance), muscular fitness (hand grip dynamometry and push-ups), physical activity (accelerometry) and resistance training skill competency were assessed at baseline and post-intervention (i.e., 8 months). Three separate multi-level mediation models were analysed to investigate the potential mediating effects of resistance training skill competency on each of the study outcomes using a product-of-coefficients test. Analyses followed the intention-to-treat principle. The intervention had a significant impact on the resistance training skill competency of the boys, and improvements in skill competency significantly mediated the effect of the intervention on percentage of body fat and the combined muscular fitness score. No significant mediated effects were found for physical activity. Improving resistance training skill competency may be an effective strategy for achieving improvements in body composition and muscular fitness in adolescent boys.  相似文献   

Dribbling determinants in sub-elite youth soccer players     

Matteo Zago  Andrea Gianluca Piovan  Isabella Annoni  Daniela Ciprandi  F. Marcello Iaia 《Journal of sports sciences》2016,34(5):411-419

Dribbling speed in soccer is considered critical to the outcome of the game and can assist in the talent identification process. However, little is known about the biomechanics of this skill. By means of a motion capture system, we aimed to quantitatively investigate the determinants of effective dribbling skill in a group of 10 Under-13 sub-elite players, divided by the median-split technique according to their dribbling test time (faster and slower groups). Foot-ball contacts cadence, centre of mass (CoM), ranges of motion (RoM), velocity and acceleration, as well as stride length, cadence and variability were computed. Hip and knee joint RoMs were also considered. Faster players, as compared to slower players, showed a 30% higher foot-ball cadence (3.0 ± 0.1 vs. 2.3 ± 0.2 contacts · s^?1, P < 0.01); reduced CoM mediolateral (0.91 ± 0.05 vs. 1.14 ± 0.16 m, P < 0.05) and vertical (0.19 ± 0.01 vs. 0.25 ± 0.03 m, P < 0.05) RoMs; higher right stride cadence (+20%, P < 0.05) with lower variability (P < 0.05); reduced hip and knee flexion RoMs (P < 0.05). In conclusion, faster players are able to run with the ball through a shorter path in a more economical way. To effectively develop dribbling skill, coaches are encouraged to design specific practices where high stride frequency and narrow run trajectories are required.  相似文献   

The effects of physical contact type on the internal and external demands during a rugby league match simulation protocol     

Jonathan P. Norris  Jamie Highton  Stephen F. Hughes  Craig Twist 《Journal of sports sciences》2016,34(19):1859-1866

The aim of this study was to investigate how the type of contact influences physiological, perceptual and locomotive load during a simulated rugby league match. Eleven male university rugby league players performed two trials of the rugby league movement simulation protocol for interchange forwards with a traditional soft tackle bag and a weighted tackle sled to replicate contact demands. The interchange forward-specific simulation was chosen given the contact frequency is higher for this group of players compared to whole match players. Locomotive rate, sprint speed, tackle intensity, heart rate (HR) and rating of perceived exertion were analysed during the first and second bouts that replicated two ~23 min on-field passages. Countermovement jump (CMJ) was measured before and immediately after each trial. More time was spent in heart rate zone between 91 and 100% HR_peak during the first (effect size ± 90% confidence interval: 0.44 ± 0.49) and second bouts (0.44 ± 0.43), and larger (0.6 ± 0.69) decrements in CMJ performance were observed during the sled trial (5.9, s = 4.9%) compared to the bag trial (2.6, s = 5.4%). Changing the type of contact during the match simulation subtly altered both the internal and external loads on participants. Using a standard tackle bag results in faster sprint speed to contact, but lower overall high-intensity running. Conversely, a heavier tackle object increases the internal load and results in greater lower limb neuromuscular fatigue as reflected by the decrease in CMJ performance.  相似文献