9,367 research outputs found

    Motion Sickness Symptomatology of Labyrinthine Defective and Normal Subjects During Zero Gravity Maneuvers

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    Motion sickness symptomology of labyrinthine defective and normal human subjects during zero gravity maneuver

    The Inversion Illusion in Parabolic Flight - Its Probable Dependence on Otolith Function

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    Comparative observations of upright perception in normal subjects and deaf persons with bilateral labyrinthine defect

    The triple task technique for studying writing processes : on which task is attention focused ?

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    The triple task technique measures the time and cognitive effort devoted to specific writing processes by combining directed retrospection with secondary task reaction time (RT). Writing a text is the primary task and rapidly detecting auditory probes to index cognitive effort is the secondary task. The third task is retrospecting and categorizing the contents of working memory at the time of each probe. The present paper reviews studies on the reactivity and validity of the technique. Further, one recent criticism of the method's validity is tested here: namely, that the primary task for the experimenter is not the primary task for the writer, thus distorting the time and effort measurements. We found that time and effort allocated to planning, translating, executing, evaluating, and revising was the same when the writer was encouraged by instructions to focus either on the speed of responding or the accuracy of retrospection instead of the text itself. Because writing requires sustained thought and attention to produce a cumulative product, it is apparently difficult to make text production anything but the primary task. The triple task technique offers a useful alternative to pause analysis and verbal protocols for investigating the functional features of writing

    Performance of the OPAL Si-W luminometer at LEP I-II

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    A pair of compact Silicon-Tungsten calorimeters was operated in the OPAL experiment at LEP to measure the integrated luminosity from detection of Bhabha electrons scattered at angles between 25 and 58 mrad from the beam line. In the eight years from 1993 to 2000 the detector worked first at the Z mass peak and then at center of mass energies up to 209 GeV. The fine radial and longitudinal segmentation (2.5mm x 1X0) allowed the radial position of electron and photon showers to be measured with a resolution of 130-170 microns and a residual radial bias as small as 7 microns. Reducing the bias in the definition of the inner acceptance radius was the key element in obtaining an experimental systematic error on the integrated luminosity of only 3.4 10^-4. The performance of the detector at both LEP-I and LEP-II is reviewed. Energy resolution, sensitivity to overlapping electromagnetic showers and sensitivity to minimum ionizing particles are discussed.Comment: 9 pages, 7 figures, 10th International Conference on Calorimetry in High Energy Physics. http://3w.hep.caltech.edu/calor02

    Motion sickness precipitated in the weightless phase of parabolic flight by Coriolis accelerations

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    Human motion sickness susceptibility when exposed to Coriolis accelerations during parabolic flight weightlessnes

    A singularly perturbed semilinear reaction-diffusion problem in a polygonal domain

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    The semilinear reaction-di®usion equation ¡"24u+b(x; u) = 0 with Dirichlet bound-ary conditions is considered in a convex polygonal domain. The singular perturbation parameter ε is arbitrarily small, and the “reduced equation” b(x, u0 (x)) = 0 may have multiple solutions. An asymptotic expansion for u is constructed that involves boundary and corner layer functions. By perturbing this asymptotic expansion, we obtain certain sub- and super-solutions and thus show the existence of a solution u that is close to the constructed asymptotic expansion. The polygonal boundary forces the study of the nonlinear autonomous elliptic equation −Dz + f (z) = 0 posed in an infinite sector, and then well-posedness of the corresponding linearized problem

    Extragalactic H 2 regions in the UV: Implications for primeval galaxies and quasars

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    Three extragalactic regions of rapid star formation with red shifts great enough to separate the L alpha region from geocoronal L alpha were observed with the IUE satellite. Only the low metal abundance object had detectable L alpha emission. L alpha is therefore expected to be weak or absent in collapsed primeval galaxies. The detected object has a L alpha H beta identical to that of quasars
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