1,836 research outputs found

    On a result of D.W. Stroock

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    We show how to modify an argument of D. W. Stroock to show that an additive map from one separable Banach space to another, that is "universally Gaussian measurable", must be continuous (hence linear)

    The Effects of a Sudden or Gradual Withdrawal from a Chronic Exercise Pattern on Anxiety Levels of Well Conditioned Athletes

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    Due to increasing numbers of people developing high levels of cardiovascular (CV) fitness there are correspondingly more leaving these elevated states for varied reasons. The present investigation explored the possible need for a taper from a chronic exercise program. Anxiety was used as a possible indication of behavioral adaptations to a decreasing level of cardiovascular and muscle endurance levels. Eighty-two conditioned subjects and thirty unconditioned subjects were pre-tested for cardiovascular levels and A-State levels of anxiety to three groups each detraining at different rates and styles. All 112 subjects were post-tested for CV and A-State levels after a two week interval. The unconditioned group showed low pre and post levels of CV fitness and low pre-levels of A-State anxiety. This low level of A-State took a large upward directional shift on A-State post-tests (37.6 to 40.8). The conditioned groups, who were detrained, dropped in levels of CV condition as per their level of modification of detraining. Their levels of A-State anxiety dropped slightly over the two week detraining interval. Significance was found at the .05 level between and among subjects for the changes in CV levels. No significance was found for the changes in A-State anxiety levels. Some directional trends could be seen as well as a possible buffering effect on A-State levels from elevated levels of CV fitness

    Absolute continuity of symmetric Markov processes

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    We study Girsanov's theorem in the context of symmetric Markov processes, extending earlier work of Fukushima-Takeda and Fitzsimmons on Girsanov transformations of ``gradient type.'' We investigate the most general Girsanov transformation leading to another symmetric Markov process. This investigation requires an extension of the forward-backward martingale method of Lyons-Zheng, to cover the case of processes with jumps.Comment: Published by the Institute of Mathematical Statistics (http://www.imstat.org) in the Annals of Probability (http://www.imstat.org/aop/) at http://dx.doi.org/10.1214/00911790400000043

    Spectroscopy of D-type asteroids

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    We have performed a spectroscopic survey of 19 D-type asteroids. Comparison with previous photometry shows excellent agreement. Although the majority have similar colors to cometary nuclei, no cometary emission bands were present in any of the spectra. Absorption bands sporadically appearing were apparently due to stellar objects, and no features inherent to the asteroids were observed

    Sputtering of Oxygen Ice by Low Energy Ions

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    Naturally occurring ices lie on both interstellar dust grains and on celestial objects, such as those in the outer solar system. These ices are continu- ously subjected to irradiation by ions from the solar wind and/or cosmic rays, which modify their surfaces. As a result, new molecular species may form which can be sputtered off into space or planetary atmospheres. We determined the experimental values of sputtering yields for irradiation of oxygen ice at 10 K by singly (He+, C+, N+, O+ and Ar+) and doubly (C2+, N2+ and O2+) charged ions with 4 keV kinetic energy. In these laboratory experiments, oxygen ice was deposited and irradiated by ions in an ultra high vacuum chamber at low temperature to simulate the environment of space. The number of molecules removed by sputtering was observed by measurement of the ice thickness using laser interferometry. Preliminary mass spectra were taken of sputtered species and of molecules formed in the ice by temperature programmed desorption (TPD). We find that the experimental sputtering yields increase approximately linearly with the projectile ion mass (or momentum squared) for all ions studied. No difference was found between the sputtering yield for singly and doubly charged ions of the same atom within the experimental uncertainty, as expected for a process dominated by momentum transfer. The experimental sputter yields are in good agreement with values calculated using a theoretical model except in the case of oxygen ions. Preliminary studies have shown molecular oxygen as the dominant species sputtered and TPD measurements indicate ozone formation.Comment: to be published in Surface Science (2015
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