1,420 research outputs found

    Spatial displays as a means to increase pilot situational awareness

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    Experiences raise a number of concerns for future spatial-display developers. While the promise of spatial displays is great, the cost of their development will be correspondingly large. The knowledge and skills which must be coordinated to ensure successful results is unprecedent. From the viewpoint of the designer, basic knowledge of how human beings perceive and process complex displays appears fragmented and largely unquantified. Methodologies for display development require prototyping and testing with subject pilots for even small changes. Useful characterizations of the range of differences between individual users is nonexistent or at best poorly understood. The nature, significance, and frequency of interpretation errors associated with complex integrated displays is unexplored and undocumented territory. Graphic displays have intuitive appeal and can achieve face validity much more readily than earlier symbolic displays. The risk of misleading the pilot is correspondingly greater. Thus while some in the research community are developing the tools and techniques necessary for effective spatial-display development, potential users must be educated about the issues so that informed choices can be made. The scope of the task facing all is great. The task is challenging and the potential for meaningful contributions at all levels is high indeed

    Heavy Metals in Greenland Seabirds, by Christian Overgaard Nielsen and Rune Dietz

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    Traces of Thermalization from Transverse Momentum Fluctuations in Nuclear Collisions

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    Scattering of particles produced in Au+Au collisions at RHIC can wrestle the system into a state near local thermal equilibrium. I illustrate how measurements of the centrality dependence of the mean transverse momentum and its fluctuations can exhibit this thermalization.Comment: 4 pages, 2 eps figures, final version to appear in PR

    Heavy ion collisions: Correlations and Fluctuations in particle production

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    Correlations and fluctuations (the latter are directly related to the 2-particle correlations) is one of the important directions in analysis of heavy ion collisions. At the current stage of RHIC exploration, when the details matter, basically any physics question is addressed with help of correlation techniques. In this talk I start with a general introduction to the correlation and fluctuation formalism and discuss weak and strong sides of different type of observables. In more detail, I discuss the two-particle ptp_t correlations/\mpt fluctuations. In spite of not observing any dramatic changes in the event-by-event fluctuations with energy, which would indicate a possible phase transition, such correlations measurements remain an interesting and important subject, bringing valuable information. Lastly, I show how radial flow can generate characteristic azimuthal, transverse momentum and rapidity correlations, which could qualitatively explain many of recently observed phenomena in nuclear collisions.Comment: 8 pages, 8 figures. Invited talk at 5th International Conference on Physics and Astrophysics of Quark Gluon Plasma, February 8-12, 2005, Salt Lake City, Kolkata, Indi

    Unbound states of 32Cl and the 31S(p,\gamma)32Cl reaction rate

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    The 31S(p,\gamma)32Cl reaction is expected to provide the dominant break-out path from the SiP cycle in novae and is important for understanding enrichments of sulfur observed in some nova ejecta. We studied the 32S(3He,t)32Cl charge-exchange reaction to determine properties of proton-unbound levels in 32Cl that have previously contributed significant uncertainties to the 31S(p,\gamma)32Cl reaction rate. Measured triton magnetic rigidities were used to determine excitation energies in 32Cl. Proton-branching ratios were obtained by detecting decay protons from unbound 32Cl states in coincidence with tritons. An improved 31S(p,\gamma)32Cl reaction rate was calculated including robust statistical and systematic uncertainties

    Evidence for anisotropic final state interactions in the two-photon ionization of rare gases

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    Synopsis Anisotropic final state interactions are exhibited most clearly in the angular momentum dependent position of Cooper minima in the photoionization partial cross section and angular distribution asymmetry parameter. We show first indication of this effect in two-photon ionization of rare gases

    Rates for the reactions antiproton-proton --> pi phi and gamma phi

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    We study antiproton-proton annihilation at rest into πϕ\pi\phi and γϕ\gamma\phi. Rescattering by KK+KK\overline{K^*}K+K^*\overline{K} and ρ+ρ\rho^{+}\rho^{-} for ppπϕ\overline{p}p\rightarrow\pi\phi states is sizable, of order (0.90to2.6)×104(0.90\, {\rm to}\,2.6)\times 10^{-4} in the branching ratio, but smaller than experiment. For ppγϕ\overline{p}p\rightarrow\gamma\phi the rescattering contributions are negligible, but the γϕ\gamma\phi channel is well explained by a ρϕ\rho\phi intermediate state combined with vector meson dominance.Comment: 12 pages, plain latex, 2 postscript figures available upon request, PSI-PR-93-2
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