THE COMPARISON TO THE CHARACTERISTICS OF THREE-DIMENSIONAL JOINT KINETICS BETWEEN SINGLE LEG AND DOUBLE LEG REBOUND JUMP

The purpose of this study was to clarify the differences between the SRJ and DRJ in terms of three-dimensional joint kinetics for the takeoff leg. Twenty male track and field athletes were performed repeated rebound jump with single leg (SRJ) and double leg (DRJ). Kinematics and kinetics data were recorded using Vicon T20 system (250 Hz) and force platforms (1000 Hz). When comparing a SRJ to a DRJ, the characteristics of the former are as follows: 1) the jump height by a single leg is significantly higher because of the larger hip joint work around the extension-flexion, especially on the abduction-adduction axes; 2) the hip extension and abduction torque is larger; and 3) in the SRJ, the hip abduction torque is larger than the hip extension torque. Therefore, the joint kinetics of the SRJ is characterized by the large hip abduction torque, in addition to the large hip extension torque

CHANGES IN THE MECHANICAL ENERGY OF THE SUPPORT LEG FOR SKILLED RACE WALKERS

The purpose of this study was to investigate changes in the mechanical energy of the legs of skilled race walkers during the support phase and to identify technical factors that produce high walking speed. Eleven skilled male race walkers walked on a 50 m walkway at the speed which was decided from the 10,000 m race record for each subject. The Ground reaction forces and motion data were collected with force platforms (500 Hz) and a high-speed VTR camera (250 Hz). Inverse dynamics was applied to compute the segmental mechanical energy and the joint kinetics of the support leg. Changes in the mechanical energy of the support leg were dependent upon the joint force power at the support hip. The increase in mechanical energy of the support leg should help the whole body drive forward and produce high walking speed

Photonic-crystal nano-photodetector with ultrasmall capacitance for on-chip light-to-voltage conversion without an amplifier

The power consumption of a conventional photoreceiver is dominated by that of the electric amplifier connected to the photodetector (PD). An ultralow-capacitance PD can overcome this limitation, because it can generate sufficiently large voltage without an amplifier when combined with a high-impedance load. In this work, we demonstrate an ultracompact InGaAs PD based on a photonic crystal waveguide with a length of only 1.7 μm and a capacitance of less than 1 fF. Despite the small size of the device, a high responsivity of 1 A/W and a clear 40 Gbit/s eye diagram are observed, overcoming the conventional trade-off between size and responsivity. A resistor-loaded PD was actually fabricated for light-to-voltage conversion, and a kilo-volt/watt efficiency with a gigahertz bandwidth even without amplifiers was measured with an electro-optic probe. Combined experimental and theoretical results reveal that a bandwidth in excess of 10 GHz can be expected, leading to an ultralow energy consumption of less than 1 fJ/bit for the photoreceiver. Amplifier-less PDs with attractive performance levels are therefore feasible and a step toward a densely integrated photonic network/processor on a chip

A feasibility study of the measurement of Higgs pair creation at a Photon Linear Collider

We studied the feasibility of the measurement of Higgs pair creation at a Photon Linear Collider (PLC). From the sensitivity to the anomalous self-coupling of the Higgs boson, the optimum $\gamma \gamma$ collision energy was found to be around 270 GeV for a Higgs mass of 120 GeV/$c^2$. We found that large backgrounds such as $\gamma \gamma \rightarrow W^+W^-, ZZ,$ and $b\bar{b}b\bar{b}$, can be suppressed if correct assignment of tracks to parent partons is achieved and Higgs pair events can be observed with a statistical significance of $\sim 5 \sigma$ by operating the PLC for 5 years.Comment: 7 pages, 8 figures, 5 table

Enhancing Inverse Problem Solutions with Accurate Surrogate Simulators and Promising Candidates

Deep-learning inverse techniques have attracted significant attention in recent years. Among them, the neural adjoint (NA) method, which employs a neural network surrogate simulator, has demonstrated impressive performance in the design tasks of artificial electromagnetic materials (AEM). However, the impact of the surrogate simulators' accuracy on the solutions in the NA method remains uncertain. Furthermore, achieving sufficient optimization becomes challenging in this method when the surrogate simulator is large, and computational resources are limited. Additionally, the behavior under constraints has not been studied, despite its importance from the engineering perspective. In this study, we investigated the impact of surrogate simulators' accuracy on the solutions and discovered that the more accurate the surrogate simulator is, the better the solutions become. We then developed an extension of the NA method, named Neural Lagrangian (NeuLag) method, capable of efficiently optimizing a sufficient number of solution candidates. We then demonstrated that the NeuLag method can find optimal solutions even when handling sufficient candidates is difficult due to the use of a large and accurate surrogate simulator. The resimulation errors of the NeuLag method were approximately 1/50 compared to previous methods for three AEM tasks. Finally, we performed optimization under constraint using NA and NeuLag, and confirmed their potential in optimization with soft or hard constraints. We believe our method holds potential in areas that require large and accurate surrogate simulators.Comment: 20 pages, 8 figure

CHANGES IN RUNNING VELOCITY AND KINETICS OF THE LOWER LIMB JOINTS IN 100 m SPRINT RUNNING

The purpose of this study was to investigate the changes in kinetics of the lower limb joints in 100 m sprint running. Nine male sprinters running 100 m with the maximum effort were videotaped at every 10 m from the start to 90 m mark with five high-speed cameras and five normal VTR cameras. Analyses of the relationship between changes in running velocity and the kinetics, joint torque, joint torque power, of the leg indicated that the critical joint kinetics factors in 100 m were: In the acceleration phase, the joint torque power exerted by the hip flexors in the early recovery phase and by the hip extensors in the late recovery phase; In the maintaining phase, the joint torque power exerted by the hip flexors in the early recovery phase and by the knee flexors in the late recovery phase

Trajectory analysis of Polar Patrol Balloon (PPB) flights in the stratosphere over Antarctica in summer and spring: A preliminary result

Actual trajectories of two PPB's which flew in the Antarctic stratosphere in austral summer and spring are compared with those calculated based on objective analysis data of Japan Meteorological Agency (JMA). The differences between the actual and calculated trajectories are discussed to check reliability of the JMA objective analysis data for the stratosphere, and to detect subsynoptic scale variability due to gravity waves and others

Age-dependent vulnerability to ischemia-reperfusion injury of cyanotic myocardium in a chronic hypoxic rat model

This study evaluated the effects of chronic hypoxia from birth on the resistance of rat hearts to global ischemia, with special emphasis on the duration of hypoxia. Male Wistar rats were housed from birth for 4 weeks or 8 weeks either in a hypoxic environment (FiO20.12) or in ambient air (8 animals for each group). Isolated rat hearts were perfused for 40 min with oxygenated Krebs-Henseleit buffer, subjected to 20 min global no-flow ischemia at 37, and then underwent 40 min of reperfusion. A non-elastic balloon was inserted into the left ventricle and inflated until the pre-ischemic LVEDP rose to 8mmHg. Cardiac function was measured before and after ischemia. The post-ischemic percent recovery of LVDP in hypoxic hearts was worse than in normoxic hearts (4 weeks:55+/-7 vs. 96+/-3%, p0.01;8 weeks:40+/-5 vs. 92+/-4%, p0.01), and was worst in the 8-week-hypoxic hearts. Similarly, the percent recovery of dP/dt in the hypoxic hearts was lower than in the normoxic hearts (4 weeks:51+/-5 vs. 96+/-7%, p0.01;8 weeks:31+/-6 vs. 92+/-7%, p0.01), and was lowest in the 8-week-hypoxic hearts. In conclusion, cyanotic myocardium revealed an age-dependent vulnerability to ischemia-reperfusion injury in a chronic hypoxic rat model.</p

Removal of Pb(II) from water using keratin colloidal solution obtained from wool

The aim of this study is to investigate the use of keratin colloidal solution, which was obtained from wool, for the removal of Pb(II) from water. The addition of keratin colloidal solution (15 g L-1, 0.30 mL) to a Pb(II) solution (1.0 mM, 0.90 mL, pH 5.0) resulted in the formation and precipitation of a Pb-keratin aggregate. Measurement of the Pb(II) and protein concentrations in the supernatant solution revealed that 88 and 99 % of the Pb(II) and keratin protein were removed from the solution, respectively. The maximum Pb(II) uptake capacity of keratin in the colloidal solution was 43.3 mg g(-1). In addition, the Pb-keratin aggregate was easily decomposed via the addition of nitric acid, which enabled the recovery of Pb(II). However, aggregation did not occur in solutions with Pb(II) concentrations below 0.10 mM. Therefore, we used a keratin colloidal solution encapsulated in a dialysis cellulose tube to remove Pb(II) from 0.10 mM solutions, which enabled the removal of 95 % of the Pb(II). From these results, we conclude that keratin colloidal solution is useful for the treatment of water polluted with Pb(II).ArticleENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH. 20(9):6531-6538 (2013)journal articl