44,598 research outputs found
Structural ambiguity of the Chinese version of the hospital anxiety and depression scale in patients with coronary heart disease
Background
The Hospital Anxiety and Depression Scale (HADS) is a widely used screening tool designed as a case detector for clinically relevant anxiety and depression. Recent studies of the HADS in coronary heart disease (CHD) patients in European countries suggest it comprises three, rather than two, underlying sub-scale dimensions. The factor structure of the Chinese version of the HADS was evaluated in patients with CHD in mainland China.
Methods
Confirmatory factor analysis (CFA) was conducted on self-report HADS forms from 154 Chinese CHD patients.
Results
Little difference was observed in model fit between best performing three-factor and two-factor models.
Conclusion
The current observations are inconsistent with recent studies highlighting a dominant underlying tri-dimensional structure to the HADS in CHD patients. The Chinese version of the HADS may perform differently to European language versions of the instrument in patients with CHD
A Narrowband Imaging Survey for High Redshift Galaxies in the Near Infrared
A narrowband imaging survey of 276 square minutes of arc was carried out at
near infrared wavelengths to search for emission line objects at high
redshifts. Most of the fields contained a known quasar or radio galaxy at a
redshift that placed one of the strong, restframe optical emission lines
(H-alpha, [O III], H-beta, or [O II]) in the bandpass of the narrowband filter.
The area weighted line flux limit over the entire survey was 3.4x10e-16
erg/cm2/s (3-sigma), while the most sensitive limits reached 1.4x10e-16
erg/cm2/s. Integrating the volume covered by all four optical emission lines in
each image yields a total comoving volume surveyed of 1.4x10e5 cubic
megaparsecs. Considering only H-alpha emission in the K band (2.05 < z < 2.65),
where the survey is most sensitive, the survey covered a comoving volume of
3.0x10e4 cubic megaparsecs to a volume-weighted average star formation rate of
112 M-solar/yr (for Ho = 50 km/s/Mpc, Omega = 1). This is the most extensive
near-infrared survey which is deep enough to have a reasonable chance at
detecting strong line emission from an actively star-forming population of
galaxies, when d against simple models of galaxy formation. One emission line
candidate was identified in this survey, and subsequently confirmed
spectroscopically.Comment: To appear in the Astronomical Journal, November 1996. 23 pages,
including 2 tables and 7 figure
Modeling Florida Fresh Tomato Supply Response: Composite Switching Regressions with Variable Weather-Determined Lags
A supply-response model for Florida fresh tomatoes is specified to analyze the impacts of the U.S. Department of Commerce's suspension agreement which governs imports of fresh tomatoes from Mexico. The particular focus is on the impact of the "reference" price which causes Mexican imports in a given week to cease if import prices in the prior week fall to the reference price. Using weekly weather data, a growing degree day (GDD) variable is constructed which predicts week of first harvest and duration of harvest. The GDD variable is used to construct the appropriate, variable lag length for weekly acres planted in four Florida production regions. A composite switching-regime model is estimated in which the regime prior to the suspension agreement occurs at a known time. The other two regimes occur when Nogales f.o.b. price are "near" or not near the reference price. Preliminary results suggest weekly Florida shipments of fresh tomatoes are more own-price elastic when Nogales f.o.b. prices near the reference price.International Relations/Trade,
Photon acceleration in variable ultra-relativistic outflows and high-energy spectra of Gamma-Ray Bursts
MeV seed photons produced in shocks in a variable ultra-relativistic outflow
gain energy by the Fermi mechanism, because the photons Compton scatter off
relativistically colliding shells. The Fermi-modified high-energy photon
spectrum has a non-universal slope and a universal cutoff. A significant
increase in the total radiative efficiency is possible. In some gamma ray
bursts, most of the power might be emitted at the high-energy cutoff for this
mechanism, which would be close to 100 MeV for outflows with a mean bulk
Lorentz factor of 100.Comment: 8 pages, submitted to ApJ
Effective Field Theory for Rydberg Polaritons
We develop an effective field theory (EFT) to describe the few- and many-body
propagation of one dimensional Rydberg polaritons. We show that the photonic
transmission through the Rydberg medium can be found by mapping the propagation
problem to a non-equilibrium quench, where the role of time and space are
reversed. We include effective range corrections in the EFT and show that they
dominate the dynamics near scattering resonances in the presence of deep bound
states. Finally, we show how the long-range nature of the Rydberg-Rydberg
interactions induces strong effective -body interactions between Rydberg
polaritons. These results pave the way towards studying non-perturbative
effects in quantum field theories using Rydberg polaritons.Comment: 5+ pages main text, 3 figures; 5 pages supplemental, 1 figure; v2 -
replaced discussion of N-body bound state preparation with discussion of
effective range corrections and made other minor correction
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