BIOMECHANICS AS PRECONDITION FOR THE UNDERSTANDING OF SWIMMING

The importance of mechanical laws for the explanation of swimming techniques is often in contrast with its consideration in the literature of swimming. This is especially true for the ''biomechanics of Swimming," as evolved after 1970 since the first International Symposium of Biomechanics in Swimming. General biomechanics, as far as documented in textbooks, does not consider this new approach sufficiently. There exists different ways of explaining swimming techniques, which are contradictory

ANALYSIS OF THE TAKE-OFF PHASE OF REVERSE DIVES PROM 3-M SPRINGBOARD: APPLICATION IN PRACTICAL TRAINING

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Cleaning up Eta Carinae: Detection of Ammonia in the Homunculus

We report the first detection of ammonia in the Homunculus nebula around eta Carinae, which is also the first detection of emission from a polyatomic molecule in this or any other luminous blue variable (LBV) nebula. Observations of the NH3 (J,K)=(3,3) inversion transition made with the Australia Telescope Compact Array reveal emission at locations where infrared H2 emission had been detected previously, near the strongest dust emission in the core of the Homunculus. We also detect ammonia emission from the so-called ``strontium filament'' in the equatorial disk. The presence of NH3 around eta Car hints that molecular shells around some Wolf-Rayet stars could have originated in prior LBV eruptions, rather than in cool red supergiant winds or the ambient interstellar medium. Combined with the lack of any CO detection, NH3 seems to suggest that the Homunculus is nitrogen rich like the ionized ejecta around eta Car. It also indicates that the Homunculus is a unique laboratory in which to study unusual molecule and dust chemistry, as well as their rapid formation in a nitrogen-rich environment around a hot star. We encourage future observations of other transitions like NH3 (1,1) and (2,2), related molecules like N2H+, and renewed attempts to detect CO.Comment: 4 pages, accepted to ApJ letter

A search for massive young stellar objects towards 98 CH3_{3}OH maser sources

Using the 13.7 m telescope of Purple Mountain Observatory (PMO), a survey of J=1-0 lines of CO and its isotopes was carried out towards 98 methanol maser sources in January 2008. Eighty-five sources have infrared counterparts within one arcmin. In the survey, except 43 sources showing complex or multiple-peak profiles, almost all the $^{13}$CO line profiles of the other 55 sources have large line widths of 4.5 km s$^{-1}$ on average and are usually asymmetric. Fifty corresponding Infrared Astronomical Satellite (IRAS) sources of these 55 sources are with $L_{bol}$ larger than $10^{3}L_{\odot}$, which can be identified as possible high-mass young stellar sources. Statistics show that the $^{13}$CO line widths correlate with the bolometric luminosity of the associated IRAS sources. We also report the mapping results of two sources: IRAS 06117+1350 and IRAS 07299-1651 here. Two cores were found in IRAS 06117+1350 and one core was detected in IRAS 07299-1651. The northwest core in IRAS 06117+1350 and the core in IRAS 07299-1651 can be identified as precursors of UC\simH{\sc ii} regions or high-mass protostellar objects (HMPOs). The southeast core of IRAS 06117+1350 has no infrared counterpart, seeming to be on younger stages than pre-UC\simH{\sc ii} phase.Comment: A search for massive young stellar objects. Accepted to RAA in 201

A BIOMECHANICAL EVALUATION OF DIVE START PERFORMANCE IN SWIMMING-FORCE DEVElOPMENT CHARACTERISTICS AND ANGULAR MOMENTUM

Dive start performance has been considered a major determinant for race swimming over short distances (e.g. Lyttle & Benjanuvatra at www.coachesinfo.com).This performance is based on chronologically interrelated sub components such as take-off performance on the block, flight performance before water contact, dive entry while immersing into the water, and gliding performance before the first swim stroke. In this "work in progress" report, we will focus on the take-off performance from the block. We will introduce a portable 2D-force measurement starting block which can be installed in different training centres and pool locations. Selected data on a research program for the biomechanical evaluation of dive start performance in swimming will be presented in order to show force development profiles from junior level swimmers. In addition, we will introduce data on the angular momentum at take-off. We will discuss some validation procedures in order to estimate the quality of the underlying calculations. To date, angular momentum has hardly been evaluated in biomechanical studies on the dive start in swimming. Nevertheless, angular momentum might play a crucial role for the angle of dive entry

ANALYSIS OF SWIMMING TECHNIQUES USING VORTEX TRACES

Propulsion in water is based on the interaction of motion body and water, respectively (under the condition of limited energy reservoir). The swimming movements are transmitting momentum creating a flow in the aquatic surrounding. Self-propulsion is a mutual result of a transfer of momentum from the propelling parts of the body on the water as well as a transfer of impulse from the water on the body, producing a counter bearing (a term indicating the application of Newton’s 3rd Law) and leaving thereby some traces. In water the traces are useful for discussions about the efficiency of swimming techniques. Here the traces of vortex (a common term for mass of whirling fluid) are emphasised. Vortices occur in different organized patterns, as trailing vortex next to the hands (front driven body) or rolling vortex in the wake of the feet (rear driven body). Trailing vortex create a zone of underpressure: it is hypothised that the hand is resited by this suction from the intended pull through the water and thus the action of the trunk-arm muscles propels the body past the hand. Rolling vortex may transfer a power stroke to the body in case the sense of its rotation is altered

DIAGNOSIS AND ADVICE IN THE UNDULATING STROKES REQUIRES INFORMATION ON GLOBAL BODY FLEXIBILITY AND UPPER LIMB STRENGTH

The locomotion and the physical characteristics of breaststroke and butterfly swimmers using the most undulating and the flattest variants will be compared. There is much more velocity variation of the centre of mass of the body in the flattest than in the most undulating variants. In the most undulating variants, during the largest part of the arm propulsion, a relatively small increase in velocity occurs. During the last part of the arm propulsion and the first part of the arm recovery, the velocity is relatively well maintained. During the first part of the bottomward leg kick, an early increase in velocity occurs. In butterfly higher flexibility scores correspond with more undulation. The individual undulation in butterfly is indicative for the best undulation in breaststroke. Flexibility and strength determine the best stroke and style variant per individual with a mean error in performance calculation of less than 3%

The Book of Proceedings of the 1st International Scientific Conference of Aquatic Space Activities

Nomura T, Ungerechts B. The Book of Proceedings of the 1st International Scientific Conference of Aquatic Space Activities. Tsukuba JAP: University of Tsukuba; 2008

A C18^{18}O study of the origin of the power-law nature in the IMF

We have performed C$^{18}$O ($J$=1--0) mapping observations of a $20'\times20'$ area of the OMC-1 region in the Orion A cloud. We identified 65 C$^{18}$O cores, which have mean radius, velocity width in FWHM, and LTE mass of 0.18$\pm$0.03 pc, 0.40$\pm$0.15 km s$^{-1}$, and 7.2$\pm$4.5 $M_\odot$, respectively. All the cores are most likely to be gravitationally bound by considering the uncertainty in the C$^{18}$O abundance. We derived a C$^{18}$O core mass function, which shows a power-law-like behavior above 5 $M_\odot$. The best-fit power-law index of $-2.3\pm0.3$ is consistent with those of the dense core mass functions and the stellar initial mass function (IMF) previously derived in the OMC-1 region. This agreement strongly suggests that the power-law form of the IMF has been already determined at the density of $\sim10^{3}$ cm$^{-3}$, traced by the C$^{18}$O ($J$=1--0) line.Comment: 17 pages, 4 figure

Real-time Sonification in Swimming: from pressure changes of displaced water to sound

Cesarini D, Hermann T, Ungerechts B. Real-time Sonification in Swimming: from pressure changes of displaced water to sound. Presented at the Multisensory Motor Behavior: Impact of Sound, Hannover, Germany