Generalized Einstein or Green-Kubo relations for active biomolecular transport

For driven Markovian dynamics on a network of (biomolecular) states, the generalized mobilities, i.e., the response of any current to changes in an external parameter, are expressed by an integral over an appropriate current-current correlation function and thus related to the generalized diffusion constants. As only input, a local detailed balance condition is required typically even valid for biomolecular systems operating deep in the non-equilibrium regime.Comment: 4 page

A Reversibility Parameter for a Markovian Stepper

Recent experimental studies on the stepwize motion of biological molecular motors have revealed that the ``characteristic distance'' of a step is usually less than the actual step size. This observation implies that the detailed-balance condition for kinetic rates of steps is violated in these motors. In this letter, in order to clarify the significance of the characteristic distance, we study a Langevin model of a molecular motor with a hidden degree of freedom. We find that the ratio of the characteristic distance to the step size is equal to unity if the dominant paths in the state space are one dimensional, while it deviates from unity if the dominant paths are branched. Therefore, this parameter can be utilized to determine the reversibility of a motor even under a restricted observation.Comment: 6 pages, 2 figures - minor revision

Ab initio simulations of liquid systems: Concentration dependence of the electric conductivity of NaSn alloys

Liquid NaSn alloys in five different compositions (20, 40, 50, 57 and 80% sodium) are studied using density functional calculations combined with molecular dynamics(Car-Parrinello method). The frequency-dependent electric conductivities for the systems are calculated by means of the Kubo-Greenwood formula. The extrapolated DC conductivities are in good agreement with the experimental data and reproduce the strong variation with the concentration. The maximum of conductivity is obtained, in agreement with experiment, near the equimolar composition. The strong variation of conductivity, ranging from almost semiconducting up to metallic behaviour, can be understood by an analysis of the densities-of-states.Comment: LaTex 6 pages and 2 figures, to appear in J.Phys. Cond. Ma

Reconstructing the global topology of the universe from the cosmic microwave background

If the universe is multiply-connected and sufficiently small, then the last scattering surface wraps around the universe and intersects itself. Each circle of intersection appears as two distinct circles on the microwave sky. The present article shows how to use the matched circles to explicitly reconstruct the global topology of space.Comment: 6 pages, 2 figures, IOP format. To be published in the proceedings of the Cleveland Cosmology and Topology Workshop 17-19 Oct 1997. Submitted to Class. Quant. Gra

Injuries to the Stomatognathic System in Tae-Kwon-Do

Martial arts are high-risk sports for injuries to the stomatognathic system, according to the FDI classification. The aim of this investigation was to determine frequency, type and severity of injuries to the stomatognathic system, during Tae-Kwon-Do, and the use of protection devices during training and competitions. This investigation included 43 examinees, 15 female and 28 male, among which were members of the national representatives of the Republic of Croatia. They were required to complete a questionnaire. The result revealed a very low number of injuries, in fact, lack of injuries in the female and male junior categories. In the male junior and both senior categories 134 injuries were reported, 118 or 88% of them were laceration of the lips, cheeks and tongue. Other injuries to the stomatognathic system represent only 16 injuries or 12% of all injuries. The majority of injuries occurred during training (68%), and 32% during competition. Protection devices (helmets) were used during training only by 5 examinees (11.63%), and during competition (100%). Mouthguards of any type were not used by any examinee. Helmets used are obligatory during competition and prevent the occurrence of injuries to the stomatognathic system, and decrease the severity of injury

Ice Islands, 1967

Five large ice islands broke away from the Ward Hunt Ice Shelf between 19 August 1961 and 18 April 1962. The largest of these was WH-5, which drifted through Nares Channel and eventually broke up. The Polar Continental Shelf Project (PCSP) has been following the movements of the four remaining ice islands WH-l, WH-2, WH-3, and WH-4 since the summer of 1963. By 1967 two of these islands, WH-3 and WH-4, had drifted out of the effective range of PCSP aircraft but the U.S. Naval Oceanographic Office "Birds Eye" flight, 3 August 1967, sighted an ice island (probably WH-4) at 71°55'N, 133°50'W. Previous to this the same organization located what was thought to be WH-3 at 73°28'N, 128°30'W on 3 April 1967. ... Of the four ice islands making up the WH group, WH-3 and WH-4 are the easiest to identify. WH-3 has a "suture" line running across one end of the ice island. WH-4 has a Jamesway hut near one corner and 10 empty 45-gallon gasoline drums lying in the shape of an "L" near the opposite corner. Because of the difficulties of positively identifying WH-l and WH-2, PCSP proposed a program to set up markers on both these islands. ... Although it is possible to estimate the rate and direction of ice island movement, it is important periodically to locate and identify particular islands. It was hoped that the drums set out by PCSP would assist the various sea ice reconnaissance groups to identify specific pieces of ice as they moved in the waters of the Arctic. Reports from the "Birds Eye" flights suggest that the specific patterns of drums are readily picked up by radar as well as the human eye, and that the drums will prove to be a very effective means of identifying ice islands