KINEMATICS OF CLEAR IN JUNIOR BADMINTON PLAYERS

Introduction the motion of rotating body segments of different shots in badminton can be described in terms of angular position, displacement, velocity or acceleration. The linear velocity of the rotating racket hitting the shuttle is directly proportional to the sum of both the angular velocity and the radius of rotation of the consecutive body segments in badminton strokes (Lee 1993). The timing of these consecutive rotational movements is important in relation to the hit of the racket with the shuttle (Gowitzke 1979).The linear momentum of the clearing arm and racket transfers to the shuttle according to the analogy of the force impulse and the change of linear momentum. The purpose of the present preliminary research was to' study the release velocity of the shuttle in maximal clear placing the shuttle on the opponent scourt in junior badminton players, to explain the produced angular and linear velocities and accelerations in the racket, hand, forearm, upper arm and trunk. METHODS Ten volunteer junior badminton player strained to perform maximal clears on the court. For motion analysis subjects performed a minimum of five successful clears. The fastest clear of every subject was selected for detailed analysis. Anthropometric data (Mean+S.D.) for the subjects was as follows: age 12.223.3years, height 1.562k0.137 m and mass46.85 11.0 kg. On average, they had training 1.851.7 years in badminton. Each clear was recorded for 3 D analysis with NAC 400 (side view) high speed video(100 fps) and Magnavox (back view)camcorder (60 fps). The optical axis of the cameras were perpendicular. The calibration scaling frame was rectangular with the dimensions of 2.0 m x 2.0-m x3.0 m. The same racket and shuttle were used in all measurements. An APAS was used to process frame crabbing, digitizing, smoothing (DLT) and transformation. The mechanical model of trunk, head, upper arm, lower arm and hand (twelwe points) was combined with the racket (four points) and shuttle. A descriptive analysis was performed on the differences in instantaneous positions, linear and rotational velocities. RESULTS The maximal release velocities of the shuttle were in the youngest subject (8years) and oldest one (19 years) 20.2and 56.0 ms-', respectively. The maximal linear velocities in the youngest and oldest subject were as follows: racket head 15.9 and 44.0 ms-' , wrist 4.7 and10.8 ms-', elbow 2.5 and 5.9 ms-' and shoulder 1.6 and 2.9 ms-', respectively. CONCLUSION In conclusion, the most experienced subject produced high speed for the shuttle through the kinematic chain of body segments with high angular and linear velocity through the impact of the shuttle and racket. The correct timing pattern of the consecutive body segments was also observed. The lengths and high angular velocities of the body segments were advantageous features for badminton players. REFERENCES Gowitzke, B.A. (1979) In: Science in Racquet Sports. J.Terauds (ed.) pp. 7-1 5.Del Mar, CA: Academic Publishers.Lee, K.B. (1993) In: Biomechanics inSports XI, J. Hamill. T.R. Derrick & E.H.Elliott (eds), pp. 239-242, University of Masschusetts, Amherst, MA

Fast convergence to equilibrium for long-chain polymer melts using a MD/continuum hybrid method

Effective and fast convergence toward an equilibrium state for long-chain polymer melts is realized by a hybrid method coupling molecular dynamics and the elastic continuum. The required simulation time to achieve the equilibrium state is reduced drastically compared with conventional equilibration methods. The polymers move on a wide range of the energy landscape due to large-scale fluctuation generated by the elastic continuum. A variety of chain structures is generated in the polymer melt which results in the fast convergence to the equilibrium state.Comment: 13 page

ArCo: the Italian Cultural Heritage Knowledge Graph

ArCo is the Italian Cultural Heritage knowledge graph, consisting of a network of seven vocabularies and 169 million triples about 820 thousand cultural entities. It is distributed jointly with a SPARQL endpoint, a software for converting catalogue records to RDF, and a rich suite of documentation material (testing, evaluation, how-to, examples, etc.). ArCo is based on the official General Catalogue of the Italian Ministry of Cultural Heritage and Activities (MiBAC) - and its associated encoding regulations - which collects and validates the catalogue records of (ideally) all Italian Cultural Heritage properties (excluding libraries and archives), contributed by CH administrators from all over Italy. We present its structure, design methods and tools, its growing community, and delineate its importance, quality, and impact

Nuclear prolate-shape dominance with the Woods-Saxon potential

We study the prolate-shape predominance of the nuclear ground-state deformation by calculating the masses of more than two thousand even-even nuclei using the Strutinsky method, modified by Kruppa, and improved by us. The influences of the surface thickness of the single-particle potentials, the strength of the spin-orbit potential, and the pairing correlations are investigated by varying the parameters of the Woods-Saxon potential and the pairing interaction. The strong interference between the effects of the surface thickness and the spin-orbit potential is confirmed to persist for six sets of the Woods-Saxon potential parameters. The observed behavior of the ratios of prolate, oblate, and spherical nuclei versus potential parameters are rather different in different mass regions. It is also found that the ratio of spherical nuclei increases for weakly bound unstable nuclei. Differences of the results from the calculations with the Nilsson potential are described in detail.Comment: 16 pages, 17 figure

Constraining dark energy fluctuations with supernova correlations

We investigate constraints on dark energy fluctuations using type Ia supernovae. If dark energy is not in the form of a cosmological constant, that is if the equation of state is not equal to -1, we expect not only temporal, but also spatial variations in the energy density. Such fluctuations would cause local variations in the universal expansion rate and directional dependences in the redshift-distance relation. We present a scheme for relating a power spectrum of dark energy fluctuations to an angular covariance function of standard candle magnitude fluctuations. The predictions for a phenomenological model of dark energy fluctuations are compared to observational data in the form of the measured angular covariance of Hubble diagram magnitude residuals for type Ia supernovae in the Union2 compilation. The observational result is consistent with zero dark energy fluctuations. However, due to the limitations in statistics, current data still allow for quite general dark energy fluctuations as long as they are in the linear regime.Comment: 18 pages, 6 figures, matches the published versio

Similarity of nuclear structure in 132Sn and 208Pb regions: proton-neutron multiplets

Starting from the striking similarity of proton-neutron multiplets in 134Sb and 210Bi, we perform a shell-model study of nuclei with two additional protons or neutrons to find out to what extent this analogy persists. We employ effective interactions derived from the CD-Bonn nucleon-nucleon potential renormalized by use of the V-low-k approach. The calculated results for 136Sb, 212Bi, 136I, and 212At are in very good agreement with the available experimental data. The similarity between 132Sn and 208Pb regions is discussed in connection with the effective interaction, emphasizing the role of core polarization effects.Comment: 4 pages, 3 figures, 2 table

Particle tracking in kaon electroproduction with cathode-charge sampling in multi-wire proportional chambers

Wire chambers are routinely operated as tracking detectors in magnetic spectrometers at high-intensity continuous electron beams. Especially in experiments studying reactions with small cross-sections the reaction yield is limited by the background rate in the chambers. One way to determine the track of a charged particle through a multi-wire proportional chamber (MWPC) is the measurement of the charge distribution induced on its cathodes. In practical applications of this read-out method, the algorithm to relate the measured charge distribution to the avalanche position is an important factor for the achievable position resolution and for the track reconstruction efficiency. An algorithm was developed for operating two large-sized MWPCs in a strong background environment with multiple-particle tracks. Resulting efficiencies were determined as a function of the electron beam current and on the signal amplitudes. Because of the different energy-losses of pions, kaons, and protons in the momentum range of the spectrometer the efficiencies depend also on the particle species

Sulfatide in health and disease. The evaluation of sulfatide in cerebrospinal fluid as a possible biomarker for neurodegeneration

Sulfatide (3-O-sulfogalactosylceramide, SM4) is a glycosphingolipid, highly multifunctional and particularly enriched in the myelin sheath of neurons. The role of sulfatide has been implicated in various biological fields such as the nervous system, immune system, host-pathogen recognition and infection, beta cell function and haemostasis/thrombosis. Thus, alterations in sulfatide metabolism and production are associated with several human diseases such as neurological and immunological disorders and cancers. The unique lipid-rich composition of myelin reflects the importance of lipids in this specific membrane structure. Sulfatide has been shown to be involved in the regulation of oligodendrocyte differentiation and in the maintenance of the myelin sheath by influencing membrane dynamics involving sorting and lateral assembly of myelin proteins as well as ion channels. Sulfatide is furthermore essential for proper formation of the axo-glial junctions at the paranode together with axonal glycosphingolipids. Alterations in sulfatide metabolism are suggested to contribute to myelin deterioration as well as synaptic dysfunction, neurological decline and inflammation observed in different conditions associated with myelin pathology (mouse models and human disorders). Body fluid biomarkers are of importance for clinical diagnostics as well as for patient stratification in clinical trials and treatment monitoring. Cerebrospinal fluid (CSF) is commonly used as an indirect measure of brain metabolism and analysis of CSF sulfatide might provide information regarding whether the lipid disruption observed in neurodegenerative disorders is reflected in this body fluid. In this review, we evaluate the diagnostic utility of CSF sulfatide as a biomarker for neurodegenerative disorders associated with dysmyelination/demyelination by summarising the current literature on this topic. We can conclude that neither CSF sulfatide levels nor individual sulfatide species consistently reflect the lipid disruption observed in many of the demyelinating disorders. One exception is the lysosomal storage disorder metachromatic leukodystrophy, possibly due to the genetically determined accumulation of non-metabolised sulfatide. We also discuss possible explanations as to why myelin pathology in brain tissue is poorly reflected by the CSF sulfatide concentration. The previous suggestion that CSF sulfatide is a marker of myelin damage has thereby been challenged by more recent studies using more sophisticated laboratory techniques for sulfatide analysis as well as improved sample selection criteria due to increased knowledge on disease pathology

A measurement of the axial form factor of the nucleon by the p(e,e'pi+)n reaction at W=1125 MeV

The reaction p(e,e'pi+)n was measured at the Mainz Microtron MAMI at an invariant mass of W=1125 MeV and four-momentum transfers of Q^2=0.117, 0.195 and 0.273 (GeV/c)^2. For each value of Q^2, a Rosenbluth separation of the transverse and longitudinal cross sections was performed. An effective Lagrangian model was used to extract the `axial mass' from experimental data. We find a value of M_A=(1.077+-0.039) GeV which is (0.051+-0.044) GeV larger than the axial mass known from neutrino scattering experiments. This is consistent with recent calculations in chiral perturbation theory.Comment: 14 pages, 5 figures, uses elsart.cl