8,050 research outputs found

    Effects of dehydration on performance in man: Annotated bibliography

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    A compilation of studies on the effect of dehydration on human performance and related physiological mechanisms. The annotations are listed in alphabetical order by first author and cover material through June 1973

    Electromagnetic wormholes via handlebody constructions

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    Cloaking devices are prescriptions of electrostatic, optical or electromagnetic parameter fields (conductivity σ(x)\sigma(x), index of refraction n(x)n(x), or electric permittivity ϵ(x)\epsilon(x) and magnetic permeability μ(x)\mu(x)) which are piecewise smooth on R3\mathbb R^3 and singular on a hypersurface Σ\Sigma, and such that objects in the region enclosed by Σ\Sigma are not detectable to external observation by waves. Here, we give related constructions of invisible tunnels, which allow electromagnetic waves to pass between possibly distant points, but with only the ends of the tunnels visible to electromagnetic imaging. Effectively, these change the topology of space with respect to solutions of Maxwell's equations, corresponding to attaching a handlebody to R3\mathbb R^3. The resulting devices thus function as electromagnetic wormholes.Comment: 25 pages, 6 figures (some color

    Domestic Drone Surveillance: The Court’s Epistemic Challenge and Wittgenstein’s Actional Certainty

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    This article examines the domestic use of drones by law enforcement to gather information. Although the use of drones for surveillance will undoubtedly provide law enforcement agencies with new means of gathering intelligence, these unmanned aircrafts bring with them a host of legal and epistemic complications. Part I considers the Fourth Amendment and the different legal standards of proof that might apply to law enforcement drone use. Part II explores philosopher Wittgenstein’s notion of actional certainty as a means to interpret citizens' expectations of privacy with regard to their patterns of movement over time. Part III discusses how the theory of actional certainty can apply to the epistemic challenge of determining what is a “reasonable” expectation of privacy under the law. This Part also investigates the Mosaic Theory as a possible reading of the Fourth Amendment

    Human acclimation and acclimatization to heat A compendium of research

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    Annotated bibliography on human acclimation and acclimatization to hea

    On kk-point configuration sets with nonempty interior

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    We give conditions for kk-point configuration sets of thin sets to have nonempty interior, applicable to a wide variety of configurations. This is a continuation of our earlier work \cite{GIT19} on 2-point configurations, extending a theorem of Mattila and Sj\"olin \cite{MS99} for distance sets in Euclidean spaces. We show that for a general class of kk-point configurations, the configuration set of a kk-tuple of sets, E1,,EkE_1,\,\dots,\, E_k, has nonempty interior provided that the sum of their Hausdorff dimensions satisfies a lower bound, dictated by optimizing L2L^2-Sobolev estimates of associated generalized Radon transforms over all nontrivial partitions of the kk points into two subsets. We illustrate the general theorems with numerous specific examples. Applications to 3-point configurations include areas of triangles in R2\mathbb R^2 or the radii of their circumscribing circles; volumes of pinned parallelepipeds in R3\mathbb R^3; and ratios of pinned distances in R2\mathbb R^2 and R3\mathbb R^3. Results for 4-point configurations include cross-ratios on R\mathbb R, triangle area pairs determined by quadrilaterals in R2\mathbb R^2, and dot products of differences in Rd\mathbb R^d.Comment: 32 pages, no figure

    Enhancement of near-cloaking. Part II: the Helmholtz equation

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    The aim of this paper is to extend the method of improving cloaking structures in the conductivity to scattering problems. We construct very effective near-cloaking structures for the scattering problem at a fixed frequency. These new structures are, before using the transformation optics, layered structures and are designed so that their first scattering coefficients vanish. Inside the cloaking region, any target has near-zero scattering cross section for a band of frequencies. We analytically show that our new construction significantly enhances the cloaking effect for the Helmholtz equation.Comment: 16pages, 12 fugure
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