3,927 research outputs found

    Visual enhancement training for baseball players

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    The purpose of this study was to determine if visual enhancement training is beneficial to a baseball player\u27s hitting abilities. We found that the group of players who received the visual training sessions showed a statistically significant (p\u3c.05) increase in their hitting abilities as compared to a group of players who did not receive the visual training sessions. This study shows that a generalized visual enhancement training program can help a baseball player improve his hitting abilities

    Axisymmetric polydimethysiloxane microchannels for in vitro hemodynamic studies

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    The current microdevices used for biomedical research are often manufactured using microelectromechanical systems (MEMS) technology. Although it is possible to fabricate precise and reproducible rectangular microchannels using soft lithography techniques, this kind of geometry may not reflect the actual physiology of the microcirculation. Here, we present a simple method to fabricate circular polydimethysiloxane (PDMS) microchannels aiming to mimic an in vivo microvascular environment and suitable for state-of-the-art microscale flow visualization techniques, such as confocal µPIV/PTV. By using a confocal µPTV system individual red blood cells (RBCs) were successfully tracked trough a 75 µm circular PDMS microchannel. The results show that RBC lateral dispersion increases with the volume fraction of RBCs in the solution, i.e. with the hematocrit

    Model-independent test of gravity with a network of ground-based gravitational-wave detectors

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    The observation of gravitational waves with a global network of interferometric detectors such as advanced LIGO, advanced Virgo, and KAGRA will make it possible to probe into the nature of space-time structure. Besides Einstein's general theory of relativity, there are several theories of gravitation that passed experimental tests so far. The gravitational-wave observation provides a new experimental test of alternative theories of gravity because a gravitational wave may have at most six independent modes of polarization, of which properties and number of modes are dependent on theories of gravity. This paper proposes a method to reconstruct the independent modes of polarization in time-series data of an advanced detector network. Since the method does not rely on any specific model, it gives model-independent test of alternative theories of gravity

    Skew Detection, Skew Normalization and Segmentation of Document Images using Segmented Block Code

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    Article信州大学工学部紀要 63: 9-18 (1988)departmental bulletin pape

    Cosmological test of gravity with polarizations of stochastic gravitational waves around 0.1-1 Hz

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    In general relativity, a gravitational wave has two polarization modes (tensor mode), but it could have additional polarizations (scalar and vector modes) in the early stage of the universe, where the general relativity may not strictly hold and/or the effect of higher-dimensional gravity may become significant. In this paper, we discuss how to detect extra-polarization modes of stochastic gravitational wave background (GWB), and study the separability of each polarization using future space-based detectors such as BBO and DECIGO. We specifically consider two plausible setups of the spacecraft constellations consisting of two and four clusters, and estimate the sensitivity to each polarization mode of GWBs. We find that a separate detection of each polarization mode is rather sensitive to the geometric configuration and distance between clusters and that the clusters should be, in general, separated by an appropriate distance. This seriously degrades the signal sensitivity, however, for suitable conditions, space-based detector can separately detect scalar, vector and tensor modes of GWBs with energy density as low as ~10^-15.Comment: 16 pages, 11 figure

    Direct Measurement of the Positive Acceleration of the Universe and Testing Inhomogeneous Models under Gravitational Wave Cosmology

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    One possibility for explaining the apparent accelerating expansion of the universe is that we live in the center of a spherically inhomogeneous universe. Although current observations cannot fully distinguish Λ\LambdaCDM and these inhomogeneous models, direct measurement of the acceleration of the universe can be a powerful tool in probing them. We have shown that, if Λ\LambdaCDM is the correct model, DECIGO/BBO would be able to detect the positive redshift drift (which is the time evolution of the source redshift zz) in 3--5 year gravitational wave (GW) observations from neutron-star binaries, which enables us to rule out any Lema\^itre-Tolman-Bondi (LTB) void model with monotonically increasing density profile. We may even be able to rule out any LTB model unless we allow unrealistically steep density profile at z0z\sim 0. This test can be performed with GW observations alone, without any reference to electromagnetic observations, and is more powerful than the redshift drift measurement using Lyman α\alpha forest.Comment: 5 pages, 2 figure
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