多段階の泳速度におけるクロール泳中の自己推進時抵抗とストリームライン姿勢中の受動抵抗の比較

The purpose of this study was to compare active drag during front-crawl swimming performed by competitive swimmers with passive drag acting on the same group of swimmers with a streamlined position at various velocities. Seven male competitive swimmers participated in this study, and the testing was conducted in a swimming flume. Active drag was evaluated for front-crawl swimming with upper and lower limb motion using a methodology that estimates the drag in swimming using measured residual thrust values (MRT method). Passive drag was measured by a load cell connected to the swimmers with a streamlined position using a stainless-steel wire. In each case, drag was estimated at six staged velocities ranging from 1.0 to 1.5 m/s. To compare the drags at various velocities, we calculated coefficients a and b by applying the measured force value at each velocity to the equation D = a vb (D: drag, v: velocity). The active drag estimated from the MRT method (a = 35.7 ± 5.3, b = 2.80 ± 0.22) was larger than passive drag (a = 23.6 ± 3.1, b = 2.08 ± 0.23). Furthermore, the difference between active and passive drag was large at high velocities. Therefore, it is possible that the effects of factors other than posture and/or body shape have a large influence on active drag, especially at high velocity

Vertical distribution of amino acids and chiral ratios in deep sea hydrothermal sub-vents of the Suiyo Seamount, Izu-Bonin Arc, Pacific Ocean

A high temperature deep sea hydrothermal system related to dacitic arc volcanism has been drilled using a tethered, submarine rock drill system as a part of the Archaean Park Project. The benthic multi-coring system (BMS) employed allows for direct sampling of microorganisms, rocks and fluids beneath hydrothermal vents. The samples examined in this study are from sites APSK 08, 09 and 10 on the Suiyo seamount of the Izu-Bonin Arc in the Pacific Ocean. Based on the vertical distribution and stereochemistry of amino acids in this vigorous sub-vent environment, a model of deep sea subterranean chemistry and biology is proposed, describing optimal microbial activity rather than abiotically synthesized amino acids components. Total hydrolyzed amino acids in the hydrothermal sub-vent core samples are of the order of 101–102 nmol/g-rock. The ratios of β-alanine/aspartic acid and γ-aminobutyric acid/glutamic acid are low, consistent with a large microbial population and fresh subterranean bioorganic compounds. The d/l ratios of chiral amino acids such as aspartic acid, glutamic acid and alanine in these rock samples were overall also quite low. Large enantiomeric excesses of l amino acids also support the existence of a vigorous subjacent microbial oasis in this seamount hydrothermal sub-system. The present findings represent crucial evidence that sub-vent regions are a previously unknown extreme environment biosphere, extending the known subterranean habitable spaces

Perception in relation to a potential influenza pandemic among healthcare workers in Japan: Implications for preparedness

10.1539/joh.50.13Journal of Occupational Health50113-2