162 research outputs found

    Relational and Neighborhood Semantics for Intuitionistic Modal Logic

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    We investigate semantics for an intuitionistic modal logic in which the “possibility” modality does not distribute over disjunction. In particular, the main aim of this paper is to study such intuitionistic modal logic as a variant of classical non-normal modal logic. We first give a neighborhood semantics together with a sound and complete axiomatization. Next, we study relationships between our approach and the relational (Kripke-style) semantics considered in the literature. It is shown that a relational model can be represented as a neighborhood model, and the converse direction holds under a slight restriction. Also, by considering degenerate cases of neighborhood and relational semantics, we demonstrate that a certain classical monotone modal logic has relational semantics, and can be embedded into a classical normal bimodal logic

    A novel method of cultivating cardiac myocytes in agarose microchamber chips for studying cell synchronization

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    We have developed a new method that enables agar microstructures to be used to cultivate cardiac myocyte cells in a manner that allows their connection patterns to be controlled. Non-contact three-dimensional photo-thermal etching with a 1064-nm infrared focused laser beam was used to form the shapes of agar microstructures. This wavelength was selected as it is not absorbed by water or agar. Identical rat cardiac myocytes were cultured in adjacent microstructures connected by microchannels and the interactions of asynchronous beating cardiac myocyte cells observed. Two isolated and independently beating cardiac myocytes were shown to form contacts through the narrow microchannels and by 90 minutes had synchronized their oscillations. This occurred by one of the two cells stopping their oscillation and following the pattern of the other cell. In contrast, when two sets of synchronized beating cells came into contact, those two sets synchronized without any observable interruptions to their rhythms. The results indicate that the synchronization process of cardiac myocytes may be dependent on the community size and network pattern of these cells

    Should energy efficiency be traded off for other product attributes? : an analysis of air-conditioner regulation in Japan

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    This paper examines the functioning of energy efficiency standards and labeling policies for air conditioners in Japan. The results of our empirical analysis suggest that consumers respond more to label information, which benchmarks the energy efficiency performance of each product to a pre-specified target, than to direct performance measures. This finding provides justification for the setting, and regular updating, of target standards as well as their use in calculating relative performance measures. We also find, through graphical analysis, that air conditioner manufacturers face a tradeoff between energy efficiency and product compactness when they develop their products. This tradeoff, combined with the semi-regular upward revision of minimum energy efficiency standards, has led to the growth in indoor unit size of air conditioners in recent years. In the face of this phenomenon, regulatory rules were revised so that manufacturers could adhere to less stringent standards if the indoor unit size of their product remains below a certain size. Our demand estimates provide no evidence that larger indoor unit size causes disutility to consumers. It is therefore possible that the regulatory change was not warranted from a consumer welfare point of view

    Stability of beating frequency in cardiac myocytes by their community effect measured by agarose microchamber chip

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    To understand the contribution of community effect on the stability of beating frequency in cardiac myocyte cell groups, the stepwise network formation of cells as the reconstructive approach using the on-chip agarose microchamber cell microcultivation system with photo-thermal etching method was applied. In the system, the shapes of agarose microstructures were changed step by step with photo-thermal etching of agarose-layer of the chip using a 1064-nm infrared focused laser beam to increase the interaction of cardiac myocyte cells during cultivation. First, individual rat cardiac myocyte in each microstructure were cultivated under isolated condition, and then connected them one by one through newly-created microchannels by photo-thermal etching to compare the contribution of community size for the magnitude of beating stability of the cell groups. Though the isolated individual cells have 50% fluctuation of beating frequency, their stability increased as the number of connected cells increased. And finally when the number reached to eight cells, they stabilized around the 10% fluctuation, which was the same magnitude of the tissue model cultivated on the dish. The result indicates the importance of the community size of cells to stabilize their performance for making cell-network model for using cells for monitoring their functions like the tissue model

    Experimental Verification of a One-Dimensional Diffraction-Limit Coronagraph

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    We performed an experimental verification of a coronagraph. As a result, we confirmed that, at the focal region where the planetary point spread function exists, the coronagraph system mitigates the raw contrast of a star-planet system by at least 1×1051\times10^{-5} even for the 1-λ/D\lambda/D star-planet separation. In addition, the verified coronagraph keeps the shapes of the off-axis point spread functions when the setup has the source angular separation of 1λ/D\lambda/D. The low-order wavefront error and the non-zero extinction ratio of the linear polarizer may affect the currently confirmed contrast. The sharpness of the off-axis point spread function generated by the sub-λ/D\lambda/D separated sources is promising for the fiber-based observation of exoplanets. The coupling efficiency with a single mode fiber exceeds 50% when the angular separation is greater than 3--4×101λ/D\times 10^{-1}\lambda/D. For sub-λ/D\lambda/D separated sources, the peak positions (obtained with Gaussian fitting) of the output point spread functions are different from the angular positions of sources; the peak position moved from about 0.8λ/D0.8\lambda/D to 1.0λ/D1.0\lambda/D as the angular separation of the light source varies from 0.1λ/D0.1\lambda/D to 1.0λ/D1.0\lambda/D. The off-axis throughput including the fiber-coupling efficiency (with respect to no focal plane mask) is about 40% for 1-λ/D\lambda/D separated sources and 10% for 0.5-λ/D\lambda/D separated ones (excluding the factor of the ratio of pupil aperture width and Lyot stop width), where we assumed a linear-polarized-light injection. In addition, because this coronagraph can remove point sources on a line in the sky, it has another promising application for high-contrast imaging of exoplanets in binary systems.Comment: 18 pages, 10 figures, accepted for the Publications of the Astronomical Society of the Pacifi

    Motion Simulator for an Underwater Glider for Long-term Virtual Mooring Including Real Devices in a Loop

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    We present an outline of a motion simulator for the prototype underwater glider “Tsukuyomi”. The project goal is the development of an underwater glider for long-term virtual mooring. When developing control software and debugging it, a motion simulator of the glider is necessary to confirm the software reliability and to improve the development efficiency. The main part of the motion simulator is installed in a PC and communicates with the Tsukuyomi central computer via LAN. It receives the glider status and simulates the dynamic motion of the glider. Then it returns the simulated result including updated depth, pitching and heading to the main controller. Consequently, it provides a virtual environment in which the glider operates.Date of Conference: 23-27 September 201
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