10,509 research outputs found

    Mechanism of Gravity Impulse

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    It is well-known that energy-momentum is the source of gravitational field. For a long time, it is generally believed that only stars with huge masses can generate strong gravitational field. Based on the unified theory of gravitational interactions and electromagnetic interactions, a new mechanism of the generation of gravitational field is studied. According to this mechanism, in some special conditions, electromagnetic energy can be directly converted into gravitational energy, and strong gravitational field can be generated without massive stars. Gravity impulse found in experiments is generated by this mechanism.Comment: 10 page

    Modelling Reference-Dependent and Labelling Effects in Consumers’ Functional Food Choices

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    This paper examines the reference-dependent and labelling effects when consumers make choices about functional foods, and explores how changes in reference points could alter individuals’ preferences. Functional food (probiotic yogurt) and regular food (regular yogurt) are used as examples to explore the potential reference-dependent effects and labelling effects. A consumer utility model with reference point effects is developed. The paper also explores how to model the effects of different labelling (health claim) policies, which could influence consumer preferences by changing consumers’ reference points.consumer utility, functional food, labelling policy, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, D11, D12,

    Modelling functional food choice and health care impacts: A literature review

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    The global market for functional foods is estimated to be worth about US$33 billion (Hilliam, 2000). Given the information asymmetry inherent in functional foods, labelling information plays a key role in allowing consumers to make informed choices. Understanding consumer choices with respect to functional foods is an important new area of research. Several potential consumer choice models are available to assess consumer choices for functional food. This paper provides an overview of key consumer research questions, and a review of several different models, including the Stated Preference Choice Model with Discrete Choice Analysis, Dependent Preference Model, and modified Protection Motivation Theory.information asymmetry, stated preference models, protection motivation, functional food, Food Consumption/Nutrition/Food Safety, Q13, I1, D12, D82,

    Non-Relativistic Limit of Dirac Equations in Gravitational Field and Quantum Effects of Gravity

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    Based on unified theory of electromagnetic interactions and gravitational interactions, the non-relativistic limit of the equation of motion of a charged Dirac particle in gravitational field is studied. From the Schrodinger equation obtained from this non-relativistic limit, we could see that the classical Newtonian gravitational potential appears as a part of the potential in the Schrodinger equation, which can explain the gravitational phase effects found in COW experiments. And because of this Newtonian gravitational potential, a quantum particle in earth's gravitational field may form a gravitationally bound quantized state, which had already been detected in experiments. Three different kinds of phase effects related to gravitational interactions are discussed in this paper, and these phase effects should be observable in some astrophysical processes. Besides, there exists direct coupling between gravitomagnetic field and quantum spin, radiation caused by this coupling can be used to directly determine the gravitomagnetic field on the surface of a star.Comment: 12 pages, no figur

    (k,q)-Compressed Sensing for dMRI with Joint Spatial-Angular Sparsity Prior

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    Advanced diffusion magnetic resonance imaging (dMRI) techniques, like diffusion spectrum imaging (DSI) and high angular resolution diffusion imaging (HARDI), remain underutilized compared to diffusion tensor imaging because the scan times needed to produce accurate estimations of fiber orientation are significantly longer. To accelerate DSI and HARDI, recent methods from compressed sensing (CS) exploit a sparse underlying representation of the data in the spatial and angular domains to undersample in the respective k- and q-spaces. State-of-the-art frameworks, however, impose sparsity in the spatial and angular domains separately and involve the sum of the corresponding sparse regularizers. In contrast, we propose a unified (k,q)-CS formulation which imposes sparsity jointly in the spatial-angular domain to further increase sparsity of dMRI signals and reduce the required subsampling rate. To efficiently solve this large-scale global reconstruction problem, we introduce a novel adaptation of the FISTA algorithm that exploits dictionary separability. We show on phantom and real HARDI data that our approach achieves significantly more accurate signal reconstructions than the state of the art while sampling only 2-4% of the (k,q)-space, allowing for the potential of new levels of dMRI acceleration.Comment: To be published in the 2017 Computational Diffusion MRI Workshop of MICCA

    Dynamics of Gravity as Thermodynamics on the Spherical Holographic Screen

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    The dynamics of general Lovelock gravity, viewed on an arbitrary spherically symmetric surface as a holographic screen, is recast as the form of some generalized first law of thermodynamics on the screen. From this observation together with other two distinct aspects, where exactly the same temperature and entropy on the screen arise, it is argued that the thermodynamic interpretation of gravity is physically meaningful not only on the horizon, but also on a general spherically symmetric screen.Comment: 10 pages, revtex4; v2: minor corrections, references added? v3: the summary paragraph replaced by the discussion of the general static case, minor corrections/clarifications/modifications, references added, match the published versio

    Critical Phenomena and Thermodynamic Geometry of RN-AdS Black Holes

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    The phase transition of Reissner-Nordstr\"om black holes in (n+1)(n+1)-dimensional anti-de Sitter spacetime is studied in details using the thermodynamic analogy between a RN-AdS black hole and a van der Waals liquid gas system. We first investigate critical phenomena of the RN-AdS black hole. The critical exponents of relevant thermodynamical quantities are evaluated. We find identical exponents for a RN-AdS black hole and a Van der Waals liquid gas system. This suggests a possible universality in the phase transitions of these systems. We finally study the thermodynamic behavior using the equilibrium thermodynamic state space geometry and find that the scalar curvature diverges exactly at the van der Waals-like critical point where the heat capacity at constant charge of the black hole diverges.Comment: 18 pages, 5 figure

    New control strategies for neuroprosthetic systems

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    The availability of techniques to artificially excite paralyzed muscles opens enormous potential for restoring both upper and lower extremity movements with\ud neuroprostheses. Neuroprostheses must stimulate muscle, and control and regulate the artificial movements produced. Control methods to accomplish these tasks include feedforward (open-loop), feedback, and adaptive control. Feedforward control requires a great deal of information about the biomechanical behavior of the limb. For the upper extremity, an artificial motor program was developed to provide such movement program input to a neuroprosthesis. In lower extremity control, one group achieved their best results by attempting to meet naturally perceived gait objectives rather than to follow an exact joint angle trajectory. Adaptive feedforward control, as implemented in the cycleto-cycle controller, gave good compensation for the gradual decrease in performance observed with open-loop control. A neural network controller was able to control its system to customize stimulation parameters in order to generate a desired output trajectory in a given individual and to maintain tracking performance in the presence of muscle fatigue. The authors believe that practical FNS control systems must\ud exhibit many of these features of neurophysiological systems
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