1,248 research outputs found
A Study Of The Impact Of Discharge Information For Surgical Patients
AIM OF THE STUDY: To establish whether the routine information surgical patients receive about the management of pain and wound care during their hospitalization is sufficient for them to care for themselves without seeking assistance from a health professional or health care agency. BACKGROUND: While there has been considerable evidence suggesting cost benefits of discharge information the health care environment is constantly changing. Contemporary issues such as increased patient participation, extensive use of technology, reduction in health care expenditure, and greater awareness of consumer rights necessitate further inquiry into the appropriateness of discharge information. METHOD: One hundred and fifty-eight adult patients discharged within a week of their operation participated in the study. A written questionnaire was distributed within 24 hours prior to discharge and a telephone interview conducted 1 to 2 weeks after discharge. At the time of discharge the majority of patients had received information. FINDINGS: Those patients who had received information were less likely to access a health facility than those who had not received information. However, the telephone interview, revealed that there was no evidence that patients who believed they were well informed within 24 hours of discharge about the management of their wound, still felt well informed 1 to 2 weeks later. CONCLUSION: Nurses need to be aware that patients who leave the hospital with little or no discharge information may not be confident in the management of their health condition and therefore may access a health facility, if even just for reassurance
Potential Harmonics Expansion Method for Trapped Interacting Bosons : Inclusion of Two-Body Correlation
We study a system of identical interacting bosons trapped by an external
field by solving ab initio the many-body Schroedinger equation. A complete
solution by using, for example, the traditional hyperspherical harmonics (HH)
basis develops serious problems due to the large degeneracy of HH basis,
symmetrization of the wave function, calculation of the matrix elements, etc.
for large . Instead of the HH basis, here we use the "potential harmonics"
(PH) basis, which is a subset of HH basis. We assume that the contribution to
the orbital and grand orbital [in -dimensional space of the reduced
motion] quantum numbers comes only from the interacting pair. This implies
inclusion of two-body correlations only and disregard of all higher-body
correlations. Such an assumption is ideally suited for the Bose-Einstein
condensate (BEC), which is extremely dilute. Unlike the hyperspherical
variables in HH basis, the PH basis involves only three {\it{active}}
variables. It drastically reduces the number of coupled equations and
calculation of the potential matrix becomes tremendously simplified, as it
involves integrals over only three variables for any . One can easily
incorporate realistic atom-atom interactions in a straight forward manner. We
study the ground and excited state properties of the condensate for both
attractive and repulsive interactions for various particle number.Comment: 36 pages, 7 included figures, plain late
The parity-violating asymmetry in the 3He(n,p)3H reaction
The longitudinal asymmetry induced by parity-violating (PV) components in the
nucleon-nucleon potential is studied in the charge-exchange reaction 3He(n,p)3H
at vanishing incident neutron energies. An expression for the PV observable is
derived in terms of T-matrix elements for transitions from the {2S+1}L_J=1S_0
and 3S_1 states in the incoming n-3He channel to states with J=0 and 1 in the
outgoing p-3H channel. The T-matrix elements involving PV transitions are
obtained in first-order perturbation theory in the hadronic weak-interaction
potential, while those connecting states of the same parity are derived from
solutions of the strong-interaction Hamiltonian with the
hyperspherical-harmonics method. The coupled-channel nature of the scattering
problem is fully accounted for. Results are obtained corresponding to realistic
or chiral two- and three-nucleon strong-interaction potentials in combination
with either the DDH or pionless EFT model for the weak-interaction potential.
The asymmetries, predicted with PV pion and vector-meson coupling constants
corresponding (essentially) to the DDH "best values" set, range from -9.44 to
-2.48 in units of 10^{-8}, depending on the input strong-interaction
Hamiltonian. This large model dependence is a consequence of cancellations
between long-range (pion) and short-range (vector-meson) contributions, and is
of course sensitive to the assumed values for the PV coupling constants.Comment: 19 pages, 15 tables, revtex
On-sky multi-wavelength phasing of segmented telescopes with the Zernike phase contrast sensor
Future Extremely Large Telescopes will adopt segmented primary mirrors with
several hundreds of segments. Cophasing of the segments together is essential
to reach high wavefront quality. The phasing sensor must be able to maintain
very high phasing accuracy during the observations, while being able to phase
segments dephased by several micrometers. The Zernike phase contrast sensor has
been demonstrated on-sky at the Very Large Telescope. We present the
multi-wavelength scheme that has been implemented to extend the capture range
from \pmlambda/2 on the wavefront to many micrometers, demonstrating that it is
successful at phasing mirrors with piston errors up to \pm4.0 micron on the
wavefront. We discuss the results at different levels and conclude with a
phasing strategy for a future Extremely Large Telescope.Comment: 17 pages, 8 figures, 2 tables. Accepted for publication in Applied
Optics; he final publised version is available on the OSA website:
http://www.opticsinfobase.org/abstract.cfm?msid=13671
A comparative evaluation of interest point detectors and local descriptors for visual SLAM
Abstract In this paper we compare the behavior of different interest points detectors and descriptors under the
conditions needed to be used as landmarks in vision-based simultaneous localization and mapping (SLAM).
We evaluate the repeatability of the detectors, as well as the invariance and distinctiveness of the descriptors,
under different perceptual conditions using sequences of images representing planar objects as well as 3D scenes.
We believe that this information will be useful when selecting an appropriat
Effect of a Physical Phase Plate on Contrast Transfer in an Aberration-Corrected Transmission Electron Microscope
In this theoretical study we analyze contrast transfer of weak-phase objects
in a transmission electron microscope, which is equipped with an aberration
corrector (Cs-corrector) in the imaging lens system and a physical phase plate
in the back focal plane of the objective lens. For a phase shift of pi/2
between scattered and unscattered electrons induced by a physical phase plate,
the sine-type phase contrast transfer function is converted into a cosine-type
function. Optimal imaging conditions could theoretically be achieved if the
phase shifts caused by the objective lens defocus and lens aberrations would be
equal zero. In reality this situation is difficult to realize because of
residual aberrations and varying, non-zero local defocus values, which in
general result from an uneven sample surface topography. We explore the
conditions - i.e. range of Cs-values and defocus - for most favourable contrast
transfer as a function of the information limit, which is only limited by the
effect of partial coherence of the electron wave in Cs-corrected transmission
electron microscopes. Under high-resolution operation conditions we find that a
physical phase plate improves strongly low- and medium-resolution object
contrast, while improving tolerance to defocus and Cs-variations, compared to a
microscope without a phase plate
Optimal Concentration of Light in Turbid Materials
In turbid materials it is impossible to concentrate light into a focus with
conventional optics. Recently it has been shown that the intensity on a dyed
probe inside a turbid material can be enhanced by spatially shaping the wave
front of light before it enters a turbid medium. Here we show that this
enhancement is due to concentration of light energy to a spot much smaller than
a wavelength. We focus light on a dyed probe sphere that is hidden under an
opaque layer. The light is optimally concentrated to a focus which does not
exceed the smallest focal area physically possible by more than 68%. A
comparison between the intensity enhancements of both the emission and
excitation light supports the conclusion of optimal light concentration.Comment: We corrected an ambiguous description of the focus size in our
abstract and text pointed out by an anonymous refere
Luneburg lens in silicon photonics
The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms. (C) 2011 Optical Society of AmericaPublisher PDFPeer reviewe
Condenser-free contrast methods for transmitted-light microscopy
Phase contrast microscopy allows the study of highly transparent yet detail-rich specimens by producing intensity contrast from phase objects within the sample. Presented here is a generalized phase contrast illumination schema in which condenser optics are entirely abrogated, yielding a condenser- free yet highly effective method of obtaining phase contrast in transmitted-light microscopy. A ring of light emitting diodes (LEDs) is positioned within the light-path such that observation of the objective back focal plane places the il- luminating ring in appropriate conjunction with the phase ring. It is demonstrated that true Zernike phase contrast is obtained, whose geometry can be flexibly manipulated to provide an arbitrary working distance between illuminator and sample. Condenser-free phase contrast is demonstrated across a range of magnifications (4–100×), numerical apertures (0.13–1.65NA) and conventional phase positions. Also demonstrated is condenser-free darkfield microscopy as well as combinatorial contrast including Rheinberg illumination and simultaneous, colour-contrasted, brightfield, darkfield and Zernike phase contrast. By providing enhanced and arbitrary working space above the preparation, a range of concurrent imaging and electrophysiological techniques will be technically facilitated. Condenser-free phase contrast is demonstrated in conjunction with scanning ion conductance microscopy (SICM), using a notched ring to admit the scanned probe. The compact, versatile LED illumination schema will further lend itself to novel next-generation transmitted-light microscopy designs. The condenser-free illumination method, using rings of independent or radially-scanned emitters, may be exploited in future in other electromagnetic wavebands, including X-rays or the infrared
Near-Infrared Imaging of a z=6.42 Quasar Host Galaxy With the Hubble Space Telescope Wide Field Camera 3
We report on deep near-infrared F125W (J) and F160W (H) Hubble Space
Telescope Wide Field Camera 3 images of the z=6.42 quasar J1148+5251 to attempt
to detect rest-frame near-ultraviolet emission from the host galaxy. These
observations included contemporaneous observations of a nearby star of similar
near-infrared colors to measure temporal variations in the telescope and
instrument point spread function (PSF). We subtract the quasar point source
using both this direct PSF and a model PSF.
Using direct subtraction, we measure an upper limit for the quasar host
galaxy of m_J>22.8, m_H>23.0 AB mag (2 sigma). After subtracting our best model
PSF, we measure a limiting surface brightness from 0.3"-0.5" radius of mu_J >
23.5, mu_H > 23.7 AB magarc (2 sigma). We test the ability of the model
subtraction method to recover the host galaxy flux by simulating host galaxies
with varying integrated magnitude, effective radius, and S\'ersic index, and
conducting the same analysis. These models indicate that the surface brightness
limit (mu_J > 23.5 AB magarc) corresponds to an integrated upper limit of m_J >
22 - 23 AB mag, consistent with the direct subtraction method. Combined with
existing far-infrared observations, this gives an infrared excess log(IRX) >
1.0 and corresponding ultraviolet spectral slope beta > -1.2\pm0.2. These
values match those of most local luminous infrared galaxies, but are redder
than those of almost all local star-forming galaxies and z~6 Lyman break
galaxies.Comment: 6 pages, 4 figures, Accepted to ApJ
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