245 research outputs found

    OVERLOAD TRAINING IN SPRINT SWIMMING: KINEMATIC AND DYNAMIC PARAMETERS

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    Overload training is used frequently to increase specific strength endurance in competitive sprint swimming. The training stimulus is provoked by exerting the competitive swimming technique, moving added external loads. These loads create an additional water resistance force to be overcome by the swimmer, thus influencing the kinematic parameters of the swimming cacle. Since quantitative data about the loads applied and the resulting changes in the swimmer's motions are not available, it is the objective of this study to present absolute data about the additional water resisitance of load equipment types commonly used, and to give an insight into the changes within the swimming cycle kinematics under defined load conditions. Two elite swimmers (male and female) being well familiar with overload training procedures served as test persons, carrying out experiments as 1) swimming with maximal effort with and without added loads, 2)towing tests at constant mean velocities as measured in free swimming with and without loads, in a passive situation as well as performing imitated crawl movenments of arms and legs but without generating any propulsive forces. The different loads applied were: clothes (as used in rescue competitions), resistance belt, and a bucket attached to the swimmer. Kinematic parameters were obtained by using a "Control Aqua Training System" (C.A.T.S.), delivering the swimmer's moving speed by registeration of the movement of a cable attached to the swimmer's waist. The towing forces were measured during gtethered swimming by use of a strain gauge system fixed to a carriage moving above a 50m indoor pool. The discussion of the numerical results is based on the mean values of swimming speed and the average towing forces, respectively, in order to avoid inertial effects or problems of nonstationary processes. In the force domain, the additive forces come to 30 to 50 percent of the water resistance during swimming without load, while a speed decrease up to 50 percent of the mean free swimming speed due to the loads added was measured. The combination of added loads and pertinent speed values shows an individual trend for each test person, allowing to perform a controlled overload training, within reasonable force and velocity ranges

    A new cellular automata model for city traffic

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    We present a new cellular automata model of vehicular traffic in cities by combining ideas borrowed from the Biham-Middleton-Levine (BML) model of city traffic and the Nagel-Schreckenberg (NaSch) model of highway traffic. The model exhibits a dynamical phase transition to a completely jammed phase at a critical density which depends on the time periods of the synchronized signals.Comment: 6 pages, 5 figures, uses Springer Macros 'lncse', to appear in "Traffic and Granular Flow '99: Social, Traffic, and Granular Dynamics" edited by D. Helbing, H. J. Herrmann, M. Schreckenberg, and D. E. Wolf (Springer, Berlin

    Unbounded-Error Classical and Quantum Communication Complexity

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    Since the seminal work of Paturi and Simon \cite[FOCS'84 & JCSS'86]{PS86}, the unbounded-error classical communication complexity of a Boolean function has been studied based on the arrangement of points and hyperplanes. Recently, \cite[ICALP'07]{INRY07} found that the unbounded-error {\em quantum} communication complexity in the {\em one-way communication} model can also be investigated using the arrangement, and showed that it is exactly (without a difference of even one qubit) half of the classical one-way communication complexity. In this paper, we extend the arrangement argument to the {\em two-way} and {\em simultaneous message passing} (SMP) models. As a result, we show similarly tight bounds of the unbounded-error two-way/one-way/SMP quantum/classical communication complexities for {\em any} partial/total Boolean function, implying that all of them are equivalent up to a multiplicative constant of four. Moreover, the arrangement argument is also used to show that the gap between {\em weakly} unbounded-error quantum and classical communication complexities is at most a factor of three.Comment: 11 pages. To appear at Proc. ISAAC 200

    Asymmetric exclusion process with next-nearest-neighbor interaction: some comments on traffic flow and a nonequilibrium reentrance transition

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    We study the steady-state behavior of a driven non-equilibrium lattice gas of hard-core particles with next-nearest-neighbor interaction. We calculate the exact stationary distribution of the periodic system and for a particular line in the phase diagram of the system with open boundaries where particles can enter and leave the system. For repulsive interactions the dynamics can be interpreted as a two-speed model for traffic flow. The exact stationary distribution of the periodic continuous-time system turns out to coincide with that of the asymmetric exclusion process (ASEP) with discrete-time parallel update. However, unlike in the (single-speed) ASEP, the exact flow diagram for the two-speed model resembles in some important features the flow diagram of real traffic. The stationary phase diagram of the open system obtained from Monte Carlo simulations can be understood in terms of a shock moving through the system and an overfeeding effect at the boundaries, thus confirming theoretical predictions of a recently developed general theory of boundary-induced phase transitions. In the case of attractive interaction we observe an unexpected reentrance transition due to boundary effects.Comment: 12 pages, Revtex, 7 figure

    A genome-wide scan for common alleles affecting risk for autism

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    Although autism spectrum disorders (ASDs) have a substantial genetic basis, most of the known genetic risk has been traced to rare variants, principally copy number variants (CNVs). To identify common risk variation, the Autism Genome Project (AGP) Consortium genotyped 1558 rigorously defined ASD families for 1 million single-nucleotide polymorphisms (SNPs) and analyzed these SNP genotypes for association with ASD. In one of four primary association analyses, the association signal for marker rs4141463, located within MACROD2, crossed the genome-wide association significance threshold of P < 5 × 10−8. When a smaller replication sample was analyzed, the risk allele at rs4141463 was again over-transmitted; yet, consistent with the winner's curse, its effect size in the replication sample was much smaller; and, for the combined samples, the association signal barely fell below the P < 5 × 10−8 threshold. Exploratory analyses of phenotypic subtypes yielded no significant associations after correction for multiple testing. They did, however, yield strong signals within several genes, KIAA0564, PLD5, POU6F2, ST8SIA2 and TAF1C
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