Challenges of Using Stereoscopic Displays in a Touch Interaction Context

This work examines how common use scenarios for touch interactive stereoscopic displays might exacerbate visual fatigue. We identify technological constraints of current stereoscopic displays and image separation techniques as the potential underlying cause and generate a set of hypotheses concerning the implications for end users. Furthermore we outline a proposed study to examine these hypotheses

F_B from moving B mesons

We show results for the B meson decay constant calculated both for B mesons at rest and those with non-zero momentum and using both the temporal and spatial components of the axial vector current. It is an important check of lattice systematic errors that all these determinations of f_B should agree. We also describe how well different smearings for the B meson work at non-zero momentum - the optimal smearing has a narrow smearing for the b quark.Comment: Lattice2001(heavyquark

Non-resonant inelastic x-ray scattering involving excitonic excitations

In a recent publication Larson \textit{et al.} reported remarkably clear $d$-$d$ excitations for NiO and CoO measured with x-ray energies well below the transition metal $K$ edge. In this letter we demonstrate that we can obtain an accurate quantitative description based on a local many body approach. We find that the magnitude of $\vec{q}$ can be tuned for maximum sensitivity for dipole, quadrupole, etc. excitations. We also find that the direction of $\vec{q}$ with respect to the crystal axes can be used as an equivalent to polarization similar to electron energy loss spectroscopy, allowing for a determination of the local symmetry of the initial and final state based on selection rules. This method is more generally applicable and combined with the high resolution available, could be a powerful tool for the study of local distortions and symmetries in transition metal compounds including also buried interfaces

The r-Process Enriched Low Metallicity Giant HD 115444

New high resolution, very high signal-to-noise spectra of ultra-metal-poor (UMP) giant stars HD 115444 and HD 122563 have been gathered with the High-Resolution Echelle Spectrometer of the McDonald Observatory 2.7m Telescope. With these spectra, line identification and model atmosphere analyses have been conducted, emphasizing the neutron-capture elements. Twenty elements with Z > 30 have been identified in the spectrum of HD 115444. This star is known to have overabundances of the neutron-capture elements, but it has lacked a detailed analysis necessary to compare with nucleosynthesis predictions. The new study features a line-by-line differential abundance comparison of HD 115444 with the bright, well-studied halo giant HD 122563. For HD 115444, the overall metallicity is [Fe/H]~ -3.0. The abundances of the light and iron-peak elements generally show the same pattern as other UMP stars (e.g. overdeficiencies of manganese and chromium, overabundances of cobalt), but the differential analysis indicates several nucleosynthesis signatures that are unique to each star.Comment: To Appear in the Astrophysical Journa

John Chalmers DaCosta (1863-1933): restoration of the old operating table.

John Chalmers DaCosta was an influential chairman and the first Samuel D. Gross Professor of Surgery at Jefferson Medical College in Philadelphia. He was well known throughout the field as a skilled surgeon, passionate speaker, and exceptional writer. In addition to countless accomplishments during his career, DaCosta was deeply dedicated to the preservation and commemoration of surgical history. This ideology was exemplified when he set out on a mission to recover the old wooden operating table used by many of his iconic mentors including Samuel D. Gross, Joseph Pancoast, and William W. Keen. This table was originally used for surgical demonstrations and anatomy lessons in a lecture room of the Ely Building and later in the great amphitheater of the Jefferson Sansom Street Hospital. It was found forgotten in the basement of the College Building and was promptly refurbished, donned with dedicatory plaques, and returned to its honored position in the medical college. Dr. DaCosta also contributed a detailed article recalling the history of the table and the notable leaders in surgery who taught and practiced on its surface. The old table currently stands proudly in the entranceway of the Department of Surgery where it will remain as a cherished symbol of the early beginnings of surgical practice and education

Measurement of Electron Trapping in the CESR Storage Ring

The buildup of low-energy electrons has been shown to affect the performance of a wide variety of particle accelerators. Of particular concern is the persistence of the cloud between beam bunch passages, which can impose limitations on the stability of operation at high beam current. We have obtained measurements of long-lived electron clouds trapped in the field of a quadrupole magnet in a positron storage ring, with lifetimes much longer than the revolution period. Based on modeling, we estimate that about 7% of the electrons in the cloud generated by a 20-bunch train of 5.3 GeV positrons with 16-ns spacing and $1.3x10^{11}$ population survive longer than 2.3 $\mu$s in a quadrupole field of gradient 7.4 T/m. We have observed a non-monotonic dependence of the trapping effect on the bunch spacing. The effect of a witness bunch on the measured signal provides direct evidence for the existence of trapped electrons. The witness bunch is also observed to clear the cloud, demonstrating its effectiveness as a mitigation technique.Comment: 6 pages, 9 figures, 28 citation

A theoretical study of the C- 4So_3/2 and 2Do_{3/2,5/2} bound states and C ground configuration: fine and hyperfine structures, isotope shifts and transition probabilities

This work is an ab initio study of the 2p3 4So_3/2, and 2Do_{3/2,5/2} states of C- and 2p2 3P_{0,1,2}, 1D_2, and 1S_0 states of neutral carbon. We use the multi-configuration Hartree-Fock approach, focusing on the accuracy of the wave function itself. We obtain all C- detachment thresholds, including correlation effects to about 0.5%. Isotope shifts and hyperfine structures are calculated. The achieved accuracy of the latter is of the order of 0.1 MHz. Intra-configuration transition probabilities are also estimated.Comment: 15 pages, 2 figures, 12 table