1,266 research outputs found
Overview of 6- X 6-foot wind tunnel aero-optics tests
The splitter-plate arrangement used in tests in the 6 x 6 foot wind tunnel and how it was configured to study boundary layers, both heated and unheated, shear layers over a cavity, separated flows behind spoilers, accelerated flows around a turret, and a turret wake are described. The flows are characterized by examples of the steady-state pressure and of velocity profiles through the various types of flow layers
Aerodynamic properties of a flat plate with cavity for optical-propagation studies
Transonic wind-tunnel tests were performed on a flat plate with and without a cube-shaped cavity and antiresonance devices. Measurements were made of the optical propagation and aerodynamic properties of the boundary and shear layers. The model and its velocity profiles and pressures are described
An experimental investigation of the velocity fluctuations behind oscillating vanes
Vortex generation and velocity fluctuations behind oscillating vane
Room temperature electron spin coherence in telecom-wavelength quaternary quantum wells
Time-resolved Kerr rotation spectroscopy is used to monitor the room
temperature electron spin dynamics of optical telecommunication wavelength
AlInGaAs multiple quantum wells lattice-matched to InP. We found that electron
spin coherence times and effective g-factors vary as a function of aluminum
concentration. The measured electron spin coherence times of these multiple
quantum wells, with wavelengths ranging from 1.26 microns to 1.53 microns,
reach approximately 100 ps at room temperature, and the measured electron
effective g-factors are in the range from -2.3 to -1.1.Comment: 4 pages, 4 figure
Effect of pulsed methylprednisolone on pain, in patients with HTLV-1-associated myelopathy
HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an immune mediated myelopathy caused by the human T-lymphotropic virus type 1 (HTLV-1). The efficacy of treatments used for patients with HAM/TSP is uncertain. The aim of this study is to document the efficacy of pulsed methylprednisolone in patients with HAM/TSP. Data from an open cohort of 26 patients with HAM/TSP was retrospectively analysed. 1g IV methylprednisolone was infused on three consecutive days. The outcomes were pain, gait, urinary frequency and nocturia, a range of inflammatory markers and HTLV-1 proviral load. Treatment was well tolerated in all but one patient. Significant improvements in pain were: observed immediately, unrelated to duration of disease and maintained for three months. Improvement in gait was only seen on Day 3 of treatment. Baseline cytokine concentrations did not correlate to baseline pain or gait impairment but a decrease in tumour necrosis factor-alpha (TNF-α) concentration after pulsed methylprednisolone was associated with improvements in both. Until compared with placebo, treatment with pulsed methylprednisolone should be offered to patients with HAM/TSP for the treatment of pain present despite regular analgesia
The Ultraviolet Detection of Diffuse Gas in Galaxy Groups
A small survey of the UV-absorbing gas in 12 low- galaxy groups has been
conducted using the Cosmic Origins Spectrograph (COS) on-board the Hubble Space
Telescope (HST). Targets were selected from a large, homogeneously-selected
sample of groups found in the Sloan Digital Sky Survey (SDSS). A critical
selection criterion excluded sight lines that pass close ( virial radii)
to a group galaxy, to ensure absorber association with the group as a whole.
Deeper galaxy redshift observations are used both to search for closer galaxies
and also to characterize these to groups, the
most massive of which are highly-virialized with numerous early-type galaxies
(ETGs). This sample also includes two spiral-rich groups, not yet
fully-virialized. At group-centric impact parameters of 0.3-2 Mpc, these
-30 spectra detected HI absorption in 7 of 12 groups; high
(OVI) and low (SiIII) ion metal lines are present in 2/3 of the absorption
components. None of the three most highly-virialized, ETG-dominated groups are
detected in absorption. Covering fractions % are seen at all impact
parameters probed, but do not require large filling factors despite an enormous
extent. Unlike halo clouds in individual galaxies, group absorbers have radial
velocities which are too low to escape the group potential well without doubt.
This suggests that these groups are "closed boxes" for galactic evolution in
the current epoch. Evidence is presented that the cool and warm group absorbers
are not a pervasive intra-group medium (IGrM), requiring a hotter (
to K) IGrM to be present to close the baryon accounting.Comment: Resubmitted to ApJS after first review; 82 pages (27 for main text,
rest are Appendices and supplemental figures and tables), 47 figures, 21
table
Pointing Guns
The American gun debate is increasingly populated with scenes of people pointing and otherwise displaying guns. What is the legal regime governing gun displays, and how well can it address the distinct social and legal problems they pose? In this Essay, we argue that the current structure of criminal law does not supply clear rules of conduct sufficient to avoid the negative effects of gun displays, and that the rhetorical and expressive effects of Second Amendment debates threaten to make the situation worse. We also suggest how the legal rules might be improved, and how battles over norms—as much as criminal prohibitions and defenses—will continue to shape both social practice and law when it comes to displays of firearms in public and towards other persons
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