418 research outputs found

    ADJUSTMENT MOVEMENT TO BASEBALLS TOSSED AT DIFFERENT VELOCITIES IN BASEBALL BATTING. -FOCUS ON A SHIFT IN THE CENTRE OF GRAVITY-

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    The purpose of this study was to compare shifts in the centre of gravity (CG) when balls were tossed at different velocities, in order to obtain data for coaching purposes. The subjects were 10 experienced university baseball players. The subject batted basic toss up ball toward the centre field, both fastballs and slowballs. Data were collected using 2 high-speed cameras (NAC Inc., Japan). The movement timing and velocity of the center of gravity were computed. Batting motion was divided into three phases. The mean times in the 1st phase and 3rd phase were approximately the same for both fast and slow balls, but both the time and distance by which the CG moved in the 2nd phase were significantly greater for slow balls than for fast balls

    Cavernous hemangioma of the accessory parotid gland.

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    ABSTRACT: We report a rare case of a hemangioma arising from the accessory parotid gland. The patient, a 45-year-old woman, complained of a right midcheek mass. Magnetic resonance imaging showed a well-defined mass located in the right buccal space, anterior to the masseter muscle, and adjacent to the Stensen duct. The mass had high T2-weighted signal intensity and showed strong patchy enhancement with gadolinium. This mass was surrounded by a common capsule with the accessory parotid gland. These findings indicated a hemangioma originating from the accessory parotid gland. The mass was completely removed by an intraoral approach without postoperative facial palsy, skin deformity, and difficulty in secreting saliva. Histologic examination of the tumor revealed multiple, thin-walled, and dilated blood vessels, confirming the diagnosis of a cavernous hemangioma. Magnetic resonance imaging was extremely useful in diagnosing the mass as a hemangioma before surgery, clarifying relationships between the mass and adjacent structures and determining the surgical approach to the mass

    Bisphosphonate-Related Osteonecrosis of the Palatal Torus

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    Background: Bisphosphonates are widely used for the treatment of osteoporosis and other bone-degrading disorders; however, bisphosphonate therapy is an important risk factor for osteonecrosis of the jaws. Methods: We report a rare case of bisphosphonate-related osteonecrosis of the palatal torus. Results: The patient was a 72-year-old woman with osteoporosis who had received 35 mg alendronate sodium hydrate once every week for 6 years. She had a 2-month history of oral pain because of intractable mucositis and ulceration of the palatal torus, with no history of malignant disease, radiation therapy, chemotherapy, steroid use, or recent dentoalveolar surgery. A CT scan showed a bony prominence at the midportion of the hard palate with erosion of its cortex. Her condition was diagnosed as stage 2 bisphosphonate-related osteonecrosis of the jaw caused by trauma, and she was advised to discontinue alendronate. She was prescribed oral antibiotics for 5 days and an oral antibacterial rinse. The mucositis with ulceration healed in approximately 10 weeks, but left a small scar. Conclusions: Although osteonecrosis of the palatal torus associated with bisphosphonate use is a rare condition, otolaryngologists should consider this condition in the differential diagnosis of intractable ulceration of the hard palate

    KINEMATIC ANALYSIS OF BASEBALL BATTING MOTION WHEN BATTING PITCHES WITH VARYING VELOCITIES

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    The purpose of this study was to identify effect of moving the center of gravity of the body and rotating the torso when batting pitches with varying velocity. The subjects were 10 experienced university baseball player. The subjects batted toward the center field, both fastballs and slowballs, aimed near the center of the strike zone from a pitching machine. Data were collected using a three dimensional automatic motion analysis system (Vicon MX). The rotation angle of the torso and displacement of the center of gravity were computed. Due to differences in the shoulder rotation from the latter half of stepping leg touchdown through impact, we believe that the motion is adapted to pitch differences starting from the latter half of stepping leg touchdown. Comparing the shift in the center of gravity of the body during fastballs and slowballs, the forward motion and downward sinking of the center of gravity were significantly larger for slowballs

    INFLUENCE OF THE BALL SPEED ON THE DISPLACEMENT OF THE CENTER OF GRAVITY DURING BASEBALL BATTING MOTION

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    The purpose of this study was to investigate the modification in batting motion with different pitching speeds focusing on differences in batting technical level. The subjects were 10 experienced university baseball player. The subjects batted toward the center field, both fastballs and slowballs, aimed near the center of the strike zone from a pitching machine. Data were collected using a three dimensional automatic motion analysis system (Vicon MX). The displacement of the center of gravity(CG) were computed. Significant differences were seen due to difference in pitching speed in unskilled player. Conversely, in skilled player, no significant difference was found in the movement of CG due to the difference in pitching speed. It was revealed that it was not preferable for movement of the CG to fluctuate by difference in pitching speeds

    Grasp Planning for a Humanoid Hand

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    Kinematic analysis of punt kick in football goalkeepers based on the level of kick effort

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    In the present study, we aimed to investigate the differences in punt kicks by football goalkeepers based on the level of effort required. Twelve experienced goalkeepers participated in the study. The participants were instructed to kick the ball as far as possible in the maximum distance trial (100% trial) and to have a more controlled approach for the 80% and 60% trials. Each punt kick was divided into three events: release of the ball from the left hand (BR), pivot foot ground-contact (LFC), and ball impact (IMP). Right lower limb joint velocity, right hip and knee joint angles, flight distance, ball velocity, and kick angle were calculated. The 80% and 100% trials yielded almost the same velocity for each part of the right leg; however, in the 60% trial, the level of kicking effort was managed by adjusting the velocity of the right ankle joint, starting from BR, in addition to adjustment of the velocity of the right knee joint at LFC. Compared to punt kicks with a lower level of effort, the punt kicks with a higher level of effort involved an increase in the hip joint extension angle for the right leg during the backswing and the lowering of the knee joint angle of the right leg at the start of the forward swing, thus producing forward swing velocity for the right foot

    Optical Measurement of Cesium Behavior in a Large H− Ion Source for a Neutral Beam Injector

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    Optical emission in a negative hydrogen ion source for the Large Helical Device Neutral Beam Injector (LHD-NBI) has been measured to investigate the behavior of Cs. Two optical sight lines exist parallel to the plasma grid, in the discharge area and in the magnetic filter area near the plasma grid. In the discharge area, the spectrum intensity from Cs+ ions is considerably increased during 20 s of the beam extraction. This indicates a considerable increase in the Cs+ density inside the plasma due to the impact of back-streaming H+ ions. A strong neutral Cs spectrum is observed in the magnetic filter area, where the electron density is lower than in the discharge area. The rate of increase of neutral Cs is much enhanced after t = 30 s, probably because the Cs adsorbed on the cooled region inside the arc chamber evaporates because its temperature increases during the long pulse discharge

    Charmed meson spectra and decay constants with one-loop O(a)O(a) improved relativistic heavy quark action

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    We calculate charmed meson spectra and decay constants in lattice QCD employing one-loop O(a)O(a) improved heavy quark action and axial-vector currents. In quenched simulations at a0.1a \sim 0.1 fm with the plaquette gauge action as well as a renormalization-group improved one, it is shown that the deviation from the continuum dispersion relation and the violation of space-time symmetry for the pseudoscalar meson decay constants are substantially reduced, once the O(a)O(a) improvement is applied. Preliminary results with two flavors of dynamical quarks are also presented.Comment: 3 pages, 4 figure, talk presented at Lattice2004(heavy), Fermilab, June 21-26, 200
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