348 research outputs found

    KINEMATIC ANALYSIS OF HURDLE CLEARANCE OF 60-M HURDLES IN ELITE HURDLE SPRINTERS DURING WORLD INDOOR CHAMPIONSHIPS 2010

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    Previous studies have examined the biomechanical variables of sprint hurdling of world-class athletes (Mero, & Luhtanen, 1986; McDonald, & Dapena, 1991). However, less is known about the factors that differentiate the performance among elite hurdle sprinters. Salo, Grimshaw, & Marar, (1997) compared international and national/county level female hurdlers and found that better hurdlers use greater take-off distance, which enables lower take-off angle and greater horizontal take-off velocity. Our previous analysis between international level hurdlers and decathletes revealed an opposite pattern of greater take-off distance for decathletes than for hurdlers (Kuitunen, Palazzi, Poon, & Peltola, 2007). The present study aims to examine the possible differences in hurdle clearance between different level of elite hurdle sprinters

    RACE PATTERN OF 60-M HURDLES IN WORLD-CLASS SPRINT HURDLERS: A BIOMECHANICAL ANALYSIS OF WORLD INDOOR CHAMPIONSHIPS 2010

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    Earlier competition reports of sprint hurdle performances show that the world-class hurdle sprinters achieve their maximal race velocity somewhere between the third and sixth hurdle (Brüggemann & Glad, 1990; Brüggemann et al., 1999). No competition analysis has been done for the indoor sprint hurdle performance, where the official distance is 60 meters consisting of five hurdles. It is not known if the hurdle sprinters change their race pattern towards a more aggressive start in the 60-m hurdle race. The purpose of the present study, therefore, was to examine the race pattern of 60-m hurdles in world-class sprint hurdlers

    LUNGE FORCES AND TECHNIQUE OF JUNIOR SQUASH PLAYERS

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    The lunge movement is used regularly in squash, as well as in other sports such as badminton and fencing, and the ability to complete a controlled lunge quickly can be a crucial part of the game (Cronin, McNair, & Marshall, 2003). The lunge has been recognised as placing high physical demands on the lower limbs, with vertical ground reaction forces (GRF) exceeding 2.5 times body weight during a badminton lunge (Kuntze, Mansfield, & Sellers, 2010). There have been a number of studies examining the forces produced by adult athletes performing a lunge movement (Lees & Hurley, 1994; Kuntze, Mansfield, & Sellers, 2010), however, to date there is very little information on the kinetics or kinematics of the squash lunge technique as performed by junior athletes. The aim of this study was to quantify and compare the ground reaction forces produced by junior squash players while performing a simulated forehand and backhand lunge shot

    Stabilization of Ge-rich defect complexes originating from E centers in Si1- xGex:P

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    Thermal evolution of vacancy complexes was studied in P-doped ([P]=10 exp 18 cm exp −3) proton irradiated Si1−xGex with Ge contents of 10%, 20%, and 30% in the range of 250–350 °C using positron annihilation spectroscopy. The radiation damage recovers in the course of anneals but the final state differs from that in as-grown samples indicating the presence of small Ge clusters in the samples, contrary to the initially random Ge distribution. The activation energy for the annealing process was estimated to be 1.4±0.3 eV and attributed to the dissociation energy of the vacancy-phosphorus-germanium (V-P-Ge) complex.Peer reviewe

    Outcome of oral immunotherapy for persistent cow's milk allergy from 11 years of experience in Finland

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    Background: The safety and efficacy of long-term milk oral immunotherapy (OIT) in Finnish children with persistent cow's milk allergy (CMA) were evaluated in an open-label, non-randomized study. Methods: During the 11-year study, 296 children aged 5 years or older with immunoglobulin E (IgE)-mediated CMA started milk OIT. Follow-up data were collected at three time points: the post-buildup phase, 1 year thereafter, and at the cross-sectional long-term follow-up between January 2016 and December 2017. Patients were divided according to baseline milk-specific IgE (sIgE) level and by the amount of milk consumption at the long-term follow-up. The high-dose group consumed >= 2 dL of milk daily, while the failure group consumed Results: Out of the initial study group, 244/296 (83%) patients participated in the long-term follow-up. Among these patients, 136/244 (56%) consumed >= 2 dL of milk daily. The median follow-up time was 6.5 years. Of the recorded markers and clinical factors, the baseline milk sIgE level was most associated with maintaining milk OIT (P <0.001). Respiratory symptoms in the post-buildup phase increased the risk of treatment failure (OR 3.5, 95% CI: 1.5-8.1, P = 0.003) and anaphylaxis (OR 14.3, 95% CI: 1.8-114, P = 0.01). Conclusion: More than half of the patients were able to maintain the targeted milk dose in their daily diet. Baseline milk sIgE level and reactivity during the early treatment stage strongly predicted the long-term outcome and safety of milk OIT.Peer reviewe

    Vacancy defects in epitaxial thin film CuGaSe2 and CuInSe2

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    Epitaxial thin film CuGaSe2 and CuInSe2 samples grown on GaAs substrates with varying [Cu]/[Ga,In] ratios were studied using positron annihilation Doppler-broadening spectroscopy and were compared to bulk crystals. We find both Cu monovacancies and Cu-Se divacancies in CuInSe2, whereas, in CuGaSe2, the only observed vacancy defect is the Cu-Se divacancy.Peer reviewe

    Alcohol Approach Bias Is Associated With Both Behavioral and Neural Pavlovian-to-Instrumental Transfer Effects in Alcohol-Dependent Patients

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    BACKGROUND: Even after qualified detoxification, alcohol-dependent (AD) patients may relapse to drinking alcohol despite their decision to abstain. Two mechanisms may play important roles. First, the impact of environmental cues on instrumental behavior (i.e., Pavlovian-to-instrumental transfer [PIT] effect), which was found to be stronger in prospectively relapsing AD patients than in abstaining patients. Second, an automatic approach bias toward alcohol stimuli was observed in AD patients, and interventions targeting this bias reduced the relapse risk in some studies. Previous findings suggest a potential behavioral and neurobiological overlap between these two mechanisms. METHODS: In this study, we examined the association between alcohol approach bias and both behavioral and neural non–drug-related PIT effects in AD patients after detoxification. A total of 100 AD patients (17 females) performed a PIT task and an alcohol approach/avoidance task. Patients were followed for 6 months. RESULTS: A stronger alcohol approach bias was associated with both a more pronounced behavioral PIT effect and stronger PIT-related neural activity in the right nucleus accumbens. Moreover, the association between alcohol approach bias and behavioral PIT increased with the severity of alcohol dependence and trait impulsivity and was stronger in patients who relapsed during follow-up in the exploratory analysis. CONCLUSIONS: A stronger alcohol approach bias was associated with both a more pronounced behavioral PIT effect and stronger PIT-related neural activity in the right nucleus accumbens. Moreover, the association between alcohol approach bias and behavioral PIT increased with the severity of alcohol dependence and trait impulsivity and was stronger in patients who relapsed during follow-up in the exploratory analysis

    Model-Based and Model-Free Control Predicts Alcohol Consumption Developmental Trajectory in Young Adults: A 3-Year Prospective Study.

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    BACKGROUND: A shift from goal-directed toward habitual control has been associated with alcohol dependence. Whether such a shift predisposes to risky drinking is not yet clear. We investigated how goal-directed and habitual control at age 18 predict alcohol use trajectories over the course of 3 years. METHODS: Goal-directed and habitual control, as informed by model-based (MB) and model-free (MF) learning, were assessed with a two-step sequential decision-making task during functional magnetic resonance imaging in 146 healthy 18-year-old men. Three-year alcohol use developmental trajectories were based on either a consumption score from the self-reported Alcohol Use Disorders Identification Test (assessed every 6 months) or an interview-based binge drinking score (grams of alcohol/occasion; assessed every year). We applied a latent growth curve model to examine how MB and MF control predicted the drinking trajectory. RESULTS: Drinking behavior was best characterized by a linear trajectory. MB behavioral control was negatively associated with the development of the binge drinking score; MF reward prediction error blood oxygen level-dependent signals in the ventromedial prefrontal cortex and the ventral striatum predicted a higher starting point and steeper increase of the Alcohol Use Disorders Identification Test consumption score over time, respectively. CONCLUSIONS: We found that MB behavioral control was associated with the binge drinking trajectory, while the MF reward prediction error signal was closely linked to the consumption score development. These findings support the idea that unbalanced MB and MF control might be an important individual vulnerability in predisposing to risky drinking behavior

    Stronger prejudices are associated with decreased model-based control

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    Background: Prejudices against minorities can be understood as habitually negative evaluations that are kept in spite of evidence to the contrary. Therefore, individuals with strong prejudices might be dominated by habitual or "automatic" reactions at the expense of more controlled reactions. Computational theories suggest individual differences in the balance between habitual/model-free and deliberative/model-based decision-making. Methods: 127 subjects performed the two Step task and completed the blatant and subtle prejudice scale. Results: By using analyses of choices and reaction times in combination with computational modeling, subjects with stronger blatant prejudices showed a shift away from model-based control. There was no association between these decision-making processes and subtle prejudices. Conclusion: These results support the idea that blatant prejudices toward minorities are related to a relative dominance of habitual decision-making. This finding has important implications for developing interventions that target to change prejudices across societies
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