Remarks on NonHamiltonian Statistical Mechanics: Lyapunov Exponents and Phase-Space Dimensionality Loss

The dissipation associated with nonequilibrium flow processes is reflected by the formation of strange attractor distributions in phase space. The information dimension of these attractors is less than that of the equilibrium phase space, corresponding to the extreme rarity of nonequilibrium states. Here we take advantage of a simple model for heat conduction to demonstrate that the nonequilibrium dimensionality loss can definitely exceed the number of phase-space dimensions required to thermostat an otherwise Hamiltonian system.Comment: 5 pages, 2 figures, minor typos correcte

POWER OUTPUT DURING THE 1ST AND 2ND PULL PHASES IN THE SNATCH BY WOMEN WEIGHTLIFTERS

The purpose of this study was to compare the power outputs of the 1st, 2nd, and total pulls in the snatch lift for women competing in the 1999 United States national championships. The performance of ten lifters was recorded and analyzed using a Peak5 2D Motion Analysis system. The power output values for the 1st, 2nd, and total pulls ranged from 604.41 W to 2329.45 W, 756.45 W to 4532.75 W, and 702.39 W to 1909.67 W, respectively. These lifters demonstrated statistically significant differences (p < 0.05) during each phase of the snatch pull, and total power output values were comparable to values previously reported (Garhammer, 1991). Knowledge of the power output during each phase of the pull may help athletes to fully refine the training leading to competition

HORIZONTAL BAR DISPLACEMENTS OF WOMEN WEIGHTLIFTERS DURING THE SNATCH

The purpose of this study was to analyze the horizontal bar displacement of women weightlifters while performing the snatch. Thirty lifts performed at the 1999 United States National Weightlifting Championships were recorded and analyzed using a Peak5 2D Motion Analysis System. Three key displacement values were obtained for each lift: first pull, second pull, and just after peak height. The magnitude of bar displacement ranged from –3 to 8cm, for the first pull –14 to 14cm, for the second pull, and –3 to 21cm just after peak height is attained. Lifters did not display the horizontal displacement pattern that is described for men in the current literature

KINEMATIC ANALYSIS OF THE BAR DROP DISPLACEMENT IN THE SNATCH

The purpose of this study was to analyze drop-under time, maximum vertical barbell displacement, vertical barbell drop and maximum vertical barbell velocity during the 1999 United States National Weightlifting Championships. The performance of ten female lifters performing 30 lifts was recorded and analyzed using a Peak5 2D Motion Analysis System. These variables were observed for lifters who successfully performed multiple lifts to determine the trends that take place as the load of the barbell increases. Average maximum vertical barbell displacement was 101.5(cm) with a SD of 7.4. Average vertical barbell drop displacement was 20.8(cm) with a SD of 5.9. Average maximum vertical velocity of the barbell was 164.8(cm/s) with a SD of 19.1. Average drop-under time was .47(s) with a SD of .09

A Common Eider × King Eider Hybrid Captured on the Kent Peninsula, Nunavut

On 25 June 2002, we captured and recorded measurements of a male common eider (Somateria mollissima) × king eider (S. spectabilis) hybrid at Nauyak Lake, on the Kent Peninsula, Nunavut. This is the first documented capture of a hybrid eider, rarely observed in North America. Structural body measurements and mass of the hybrid were intermediate compared to those of Pacific common eiders (S. m. v-nigrum) at the same study site and king eiders at a nearby study site during the same time of year. The plumage of the captured hybrid had characteristics of both parent species. Mate pairing on overlapping spring staging or wintering areas of common and king eiders may occasionally result in hybrid offspring.Le 25 juin 2002, nous avons capturé un hybride composé d’un eider à duvet (Somateria mollissima) × un eider à tête grise (S. spectabilis) au lac Nauyak, dans la péninsule de Kent, au Nunavut, puis nous avons pris note de ses mesures. Il s’agit de la première capture répertoriée d’un eider hybride, ce qui est rarement observé en Amérique du Nord. Les mesures et la masse de la structure corporelle de l’hybride étaient intermédiaires comparativement à celles des eiders à duvet du Pacifique (S. m. v-nigrum) du même lieu d’étude et à celles des eiders à tête grise d’un lieu d’étude avoisinant pendant la même période de l’année. Le plumage de l’hybride que nous avons capturé présentait des caractéristiques des deux espèces. Il arrive parfois que les accouplements aux haltes migratoires du printemps ou aux aires d’hivernage partagées par les eiders à duvet et les eiders à tête grise donnent lieu à une progéniture hybride

Lyapunov instability for a periodic Lorentz gas thermostated by deterministic scattering

In recent work a deterministic and time-reversible boundary thermostat called thermostating by deterministic scattering has been introduced for the periodic Lorentz gas [Phys. Rev. Lett. {\bf 84}, 4268 (2000)]. Here we assess the nonlinear properties of this new dynamical system by numerically calculating its Lyapunov exponents. Based on a revised method for computing Lyapunov exponents, which employs periodic orthonormalization with a constraint, we present results for the Lyapunov exponents and related quantities in equilibrium and nonequilibrium. Finally, we check whether we obtain the same relations between quantities characterizing the microscopic chaotic dynamics and quantities characterizing macroscopic transport as obtained for conventional deterministic and time-reversible bulk thermostats.Comment: 18 pages (revtex), 7 figures (postscript

Drought-stressed, irrigated, and additive-treated corn silages for growing cattle

Cattle fed drought-stressed corn silage gained about 10% slower but were just as efficient as cattle fed irrigated corn silage. Because the irrigated corn out yielded the drought corn (17.4 VS. 8.2 tons per acre), the irrigated silage gave a much higher cattle gain per acre (1928 VS. 940 1b). Silo Guard II®-treated silage had an advantage in DM recovery and feed conversion over its control and produced 4.6 more pounds of cattle gain per ton of crop ensiled. Cattle fed H/M Inoculant®- treated silage gained significantly faster than cattle fed the control, however, the treated silage gave only slight improvements in DM recovery and gain per ton of crop ensiled

Ion dynamics in a linear radio-frequency trap with a single cooling laser

We analyse the possibility of cooling ions with a single laser beam, due to the coupling between the three components of their motion induced by the Coulomb interaction. For this purpose, we numerically study the dynamics of ion clouds of up to 140 particles, trapped in a linear quadrupole potential and cooled with a laser beam propagating in the radial plane. We use Molecular Dynamics simulations and model the laser cooling by a stochastic process. For each component of the motion, we systematically study the dependence of the temperature with the anisotropy of the trapping potential. Results obtained using the full radio-frequency (rf) potential are compared to those of the corresponding pseudo-potential. In the rf case, the rotation symmetry of the potential has to be broken to keep ions inside the trap. Then, as for the pseudo-potential case, we show that the efficiency of the Coulomb coupling to thermalize the components of motion depends on the geometrical configuration of the cloud. Coulomb coupling appears to be not efficient when the ions organise as a line or a pancake and the three components of motion reach the same temperature only if the cloud extends in three dimensions

Brownian Motors driven by Particle Exchange

We extend the Langevin dynamics so that particles can be exchanged with a particle reservoir. We show that grand canonical ensembles are realized at equilibrium and derive the relations of thermodynamics for processes between equilibrium states. As an application of the proposed evolution rule, we devise a simple model of Brownian motors driven by particle exchange. KEYWORDS: Langevin Dynamics, Thermodynamics, Open SystemsComment: 5 pages, late