14,479 research outputs found
Mars: Seasonally variable radar reflectivity
The 1971/1973 Mars data set acquired by the Goldstone Solar System Radar was analyzed. It was established that the seasonal variations in radar reflectivity thought to occur in only one locality on the planet (the Solis Lacus radar anomaly) occur, in fact, over the entire subequatorial belt observed by the Goldstone radar. Since liquid water appears to be the most likely cause of the reflectivity excursions, a permanent, year-round presence of subsurface water (frozen or thawed) in the Martian tropics can be inferred
Negative oxygen vacancies in HfO as charge traps in high-k stacks
We calculated the optical excitation and thermal ionization energies of
oxygen vacancies in m-HfO using atomic basis sets, a non-local density
functional and periodic supercell. The thermal ionization energies of
negatively charged V and V centres are consistent with values
obtained by the electrical measurements. The results suggest that negative
oxygen vacancies are the likely candidates for intrinsic electron traps in the
hafnum-based gate stack devices.Comment: 3 pages, 2 figure
Operating experience with four 200 kW Mod-0A wind turbine generators
The windpowered generator, Mod-0A, and its advantages and disadvantages, particularly as it affects reliability, are discussed. The machine performance with regard to power availability and power output is discussed
Two new topologically ordered glass phases of smectics confined in anisotropic random media
We show that smectic liquid crystals confined in_anisotropic_ porous
structures such as e.g.,_strained_ aerogel or aerosil exhibit two new glassy
phases. The strain both ensures the stability of these phases and determines
their nature. One type of strain induces an ``XY Bragg glass'', while the other
creates a novel, triaxially anisotropic ``m=1 Bragg glass''. The latter
exhibits anomalous elasticity, characterized by exponents that we calculate to
high precision. We predict the phase diagram for the system, and numerous other
experimental observables.Comment: 4 RevTeX pgs, 2 eps figures, submitted to Phys. Rev. Let
Indicators of Woman Abuse Based on a Chart Review at a Family Practice Center
Objective: To identify demographic and health indicators
of domestic violence.
Design: Anonymous questionnaire survey of patients regarding
violence and a chart review regarding symptoms
and diagnoses.
Setting: Community-based family practice residency training
center in a midwestern city.
Participants: Women 18 years of age or older visiting
the center over a 2-month period in 1990. Of 476
eligible participants, 394 (82.7%) consented to complete
the survey.
Measures: A detailed, standardized measure of violence
was used. Physical and psychological problems
were given codes from the International Classification of
Diseases, Ninth Revision (ICD-9).
Results: Younger women and those separated or divorced
from their partners were more likely to have been victims.
Never-married women also had substantially high rates of
victimization. Depression was the strongest indicator of victimization,
even when controlling for demographic factors.
Back pain, ulcers, headaches, and anxiety were not strong
indicators of abuse. A classification analysis showed that
a combination of all variables could predict lifetime injury
only about half the time and violence in the past year only
about 20% of the time.
Conclusions: Since neither demographic nor health factors
could accurately predict who had been victimized, all
women need to be asked about abuse. Physicians should
also keep in mind that divorced and unmarried women are
often affected by abuse, either immediately or by its long
term aftereffects.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89971/1/Saunders-Hamberger-Hovey-1993-Indicators of woman abuse based on a chart review at a family practice center AFM-AMA.pd
The IRAS 1-Jy Survey of Ultraluminous Infrared Galaxies: I. The sample and Luminosity Function
A complete flux-limited sample of 118 ultraluminous infrared galaxies (ULIGs)
has been identified from the IRAS Faint Source Catalog (FSC). The selection
criteria were a 60 micron flux density greater than 1 Jy in a region of the sky
delta > -40 deg, |b| > 30 deg. All sources were subsequently reprocessed using
coadded IRAS maps in order to obtain the best available flux estimates in all
four IRAS wavelength bands. The maximum observed infrared luminosity is L_ir =
10^{12.90} L_{sun}, and the maximum redshift is z = 0.268. The luminosity
function for ULIGs over the decade luminosity range L_ir = 10^{12} - 10^{13}
L_{sun} can be approximated by a power law Phi (L) ~= L^{-2.35} Mpc^{-3}
mag^{-1}. In the local Universe z < 0.1, the space density of ULIGs appears to
be comparable to or slightly larger than that of optically selected QSOs at
comparable bolometric luminosities. A maximum likelihood test suggests strong
evolution for our sample; assuming density evolution proportional to
(1+z)^{alpha} we find alpha = 7.6+/-3.2. Examination of the two-point
correlation function shows a barely significant level of clustering, xi (r) =
1.6 +/- 1.2, on size scales r ~= 22 h^{-1} Mpc.Comment: 18 pages of text, 10 pages of figures 1 to 6, 6 pages of tables 1 to
3, ApJS accepte
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