790 research outputs found

    Electroweak Constraints from Atomic Parity Violation and Neutrino Scattering

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    Precision electroweak physics can provide fertile ground for uncovering new physics beyond the Standard Model (SM). One area in which new physics can appear is in so-called "oblique corrections", i.e., next-to-leading order expansions of bosonic propagators corresponding to vacuum polarization. One may parametrize their effects in terms of quantities SS and TT that discriminate between conservation and non-conservation of isospin. This provides a means of comparing the relative contributions of precision electroweak experiments to constraints on new physics. Given the prevalence of strongly TT-sensitive experiments, there is an acute need for further constraints on SS, such as provided by atomic parity-violating experiments on heavy atoms. We evaluate constraints on SS arising from recently improved calculations in the Cs atom. We show that the top quark mass mtm_t provides stringent constraints on SS within the context of the Standard Model. We also consider the potential contributions of next-generation neutrino scattering experiments to improved (S,T)(S,T) constraints.Comment: 10 pages, 4 figures, final corrected version to be published in Physical Review

    Introduction

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    European mineral statistics 2002-06 : a product of the World Mineral Statistics database

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    European Mineral Statistics has over 300 pages of tables on minerals production and trade. Thirty two countries are covered including all the EU members, EU applicants, Norway and Switzerland. In the first section there are tables by country, followed by commodity tables with selected graphics and bullet points with information on use and prices

    Three-dimensional kinematic correlates of ball velocity during maximal instep soccer kicking in males

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    This is an Accepted Manuscript of an article published by Taylor & Francis Group in European Journal of Sport Science, on 23 April 2014, available online at: https://www.tandfonline.com/doi/abs/10.1080/17461391.2014.908956.Achieving a high ball velocity is important during soccer shooting, as it gives the goalkeeper less time to react, thus improving a player's chance of scoring. This study aimed to identify important technical aspects of kicking linked to the generation of ball velocity using regression analyses. Maximal instep kicks were obtained from 22 academy-level soccer players using a 10-camera motion capture system sampling at 500 Hz. Three-dimensional kinematics of the lower extremity segments were obtained. Regression analysis was used to identify the kinematic parameters associated with the development of ball velocity. A single biomechanical parameter; knee extension velocity of the kicking limb at ball contact Adjusted R(2) = 0.39, p ≤ 0.01 was obtained as a significant predictor of ball-velocity. This study suggests that sagittal plane knee extension velocity is the strongest contributor to ball velocity and potentially overall kicking performance. It is conceivable therefore that players may benefit from exposure to coaching and strength techniques geared towards the improvement of knee extension angular velocity as highlighted in this study.Peer reviewedFinal Accepted Versio

    Posture flexibility and grip strength in horse riders

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    Since the ability to train the horse to be ambidextrous is considered highly desirable, rider asymmetry is recognized as a negative trait. Acquired postural and functional asymmetry can originate from numerous anatomical regions, so it is difficult to suggest if any is developed due to riding. The aim of this study was therefore to assess symmetry of posture, strength and flexibility in a large population of riders and to determine whether typical traits exist due to riding. 127 right handed riders from the UK and USA were categorized according to years riding (in 20 year increments) and their competition level (using affiliated test levels). Leg length, grip strength and spinal posture were measured and recorded by a physiotherapist. Standing and sitting posture and trunk flexibility were measured with 3-D motion capture technology. Right-left differences were explored in relation to years riding and rider competitive experience. Significant anatomical asymmetry was found for the difference in standing acromion process height for a competition level (-0.07±1.50 cm Intro/Prelim; 0.02±1.31 cm Novice; 0.43±1.27 cm Elementary+; p=0.048) and for sitting iliac crest height for years riding (-0.23±1.36 cm Intro/Prelim; 0.01±1.50 cm Novice; 0.86±0.41 cm Elementary+;p=0.021). For functional asymmetry, a significant interaction was found for lateral bending ROM for years riding x competition level (p=0.047). The demands on dressage riders competing at higher levels may predispose these riders to a higher risk of developing asymmetry and potentially chronic back pain rather than improving their symmetry

    Effects of barefoot and minimally shod footwear on effective mass - implications for transient musculoskeletal loading

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    The purpose of this investigation was to explore the effects of barefoot and minimally shod footwear on effective mass, and determine the implications that this has for transient loading during running. Fifteen male runners ran at 4.0 m/s in five different footwear conditions (barefoot, running trainer, Nike-free, Inov-8 and Vibram five-fingers). Kinematics were collected using an 8 camera motion capture system and ground reaction forces via an embedded force platform. Effective mass was examined using impulse-momentum modelling. Differences between footwear were examined using one-way repeated measures ANOVA and linear regression was used to determine the association between effective mass and instantaneous loading rate. The findings showed that effective mass was significantly larger in the barefoot (11.47 %BW), Nike-free (9.81 %BW), Inov-8 (12.10 %BW) and Vibram five-fingers (8.84 %BW) compared to the running trainer (6.86 %BW). Furthermore, instantaneous loading rate was significantly larger in the barefoot (347.55 BW/s), Nike-free (178.76 BW/s), Inov-8 (369.93 BW/s) and Vibram five-fingers (339.37 BW/s) compared to the running trainer (133.18 BW/s). It was also revealed that there were significant positive associations between effective mass and the instantaneous rate for each footwear; barefoot (R2=0.60), Nike-free (R2=0.53), Inov-8 (R2=0.80), Vibram five-fingers (R2=0.52) and running trainer (R2=0.40). The findings from the current investigation indicate that effective mass has key implications for the generation of transient forces and also that running barefoot and in minimally shod footwear may place runners at increased risk from impact related injuries compared to the traditional running shoes

    Monogenic hypercholesterolemia: new insights in pathogenesis and treatment

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