4,046 research outputs found
The Development and assessment of reliability and validity of a questionnaire to measure concordance to ‘pressure relief’ regimen for pressure injury prevention in seated spinal cord injury
Magnetization reversal and spin dynamics exchange in biased F/AF bilayers probed with complex permeability spectra
The spin dynamics of the ferromagnetic pinned layer of
ferro-antiferromagnetic coupled NiFe/MnNi bilayers is investigated in a broad
frequency range (30 MHz-6 GHz). A phenomenological model based on the
Landau-Lifshitz equation for the complex permeability of the F/AF bilayer is
proposed. The experimental results are compared to theoretical predictions. We
show that the resonance frequencies, measured during the magnetization, are
likewise hysteretic.Comment: 4 pages, 4 figure
The Retirement Adjustment Process: Changes in the Well-being of Male Retirees Across Time
The purpose of this prospective study was to (1) evaluate the impact of retirement, (2) monitor the change in adjustment across time, and (3) identify the resources predictive of short- and long-term adjustment in retirement. A sample of 117 male retirees was assessed on indices of physical and psychological health, perceived control, retirement satisfaction, and life satisfaction at 2-4 months preretirement, 1 year post-, and 6-7 years postretirement. The results provided support for a positive impact of retirement, as retirees evidenced increases in well-being during the first year. There was also evidence of a retirement adjustment process, in that aspects of well-being (i.e., psychological health) changed from short- to long-term retirement. Finally, physical health, income, and voluntary retirement status predicted short-term adjustment, while internal locus of control was an additional resource for long-term adjustment. Changes in resources over time also differentially predicted short- and long-term adjustment (e.g., an increase in internal locus of control predicted an increase in activity satisfaction at 1 year but not at 6-7 years postretirement
The Distance to NGC 4993: The Host Galaxy of the Gravitational-wave Event GW170817
The historic detection of gravitational waves from a binary neutron star
merger (GW170817) and its electromagnetic counterpart led to the first accurate
(sub-arcsecond) localization of a gravitational-wave event. The transient was
found to be 10" from the nucleus of the S0 galaxy NGC 4993. We report
here the luminosity distance to this galaxy using two independent methods. (1)
Based on our MUSE/VLT measurement of the heliocentric redshift () we infer the systemic recession velocity of the
NGC 4993 group of galaxies in the cosmic microwave background (CMB) frame to be
km s. Using constrained cosmological
simulations we estimate the line-of-sight peculiar velocity to be km s, resulting in a cosmic velocity of km s () and a
distance of Mpc assuming a local Hubble constant of
km s Mpc. (2) Using Hubble Space Telescope
measurements of the effective radius (15.5" 1.5") and contained intensity
and MUSE/VLT measurements of the velocity dispersion, we place NGC 4993 on the
Fundamental Plane (FP) of E and S0 galaxies. Comparing to a frame of 10
clusters containing 226 galaxies, this yields a distance estimate of Mpc. The combined redshift and FP distance is Mpc. This 'electromagnetic' distance estimate is consistent
with the independent measurement of the distance to GW170817 as obtained from
the gravitational-wave signal ( Mpc) and
confirms that GW170817 occurred in NGC 4993.Comment: 9 pages, 5 figure
Canonical-basis solution of the Hartree-Fock-Bogoliubov equation on three-dimensional Cartesian mesh
A method is presented to obtain the canonical-form solutions of the HFB
equation for atomic nuclei with zero-range interactions like the Skyrme force.
It is appropriate to describe pairing correlations in the continuum in
coordinate-space representations. An improved gradient method is used for
faster convergences under constraint of orthogonality between orbitals. To
prevent high-lying orbitals to shrink into a spatial point, a repulsive
momentum dependent force is introduced, which turns out to unveil the nature of
high-lying canonical-basis orbitals. The asymptotic properties at large radius
and the relation with quasiparticle states are discussed for the obtained
canonical basis.Comment: 23 pages including 17 figures, REVTeX4, revised version, scheduled to
appear in Phys. Rev. C, Vol.69, No.
Development and preliminary validation of a tool measuring concordance and belief about performing pressure-relieving activities for pressure ulcer prevention in spinal cord injury
Objective: To develop and examine the reliability, and validity of a questionnaire measuring concordance for performing pressure-relief for pressure ulcer (PrU) prevention in people with Spinal Cord Injury (SCI).
Methods: Phase I included item development, content and face validity testing. In phase II, the questionnaire was evaluated for preliminary acceptability, reliability and validity among 48 wheelchair users with SCI.
Results: Thirty-seven items were initially explored. Item and factor analysis resulted in a final 26-item questionnaire with four factors reflecting concordance, perceived benefits, perceived negative consequences, and personal practical barriers to performing pressure-relief activities. The internal consistency reliability for four domains were very good (Cronbach's α = .75-.89). Pearson correlation coefficient on a test-retest of the same subjects yielded significant correlations in concordance (r = .91, p = .005), perceived benefit (r = .71, p < .04), perceived negative consequences (r = .98, p < .0001), personal barriers (r = .93, p= .002). Participants with higher levels of concordance reported a greater amount of pressure-relieving performed. Individuals viewing PrU as a threatening illness were associated with higher scores of concordance and tended to report a greater amount of pressure-relieving performance which provides evidence of criterion related validity.
Conclusion: The new questionnaire demonstrated good preliminary reliability and validity in people with SCI. Further evaluation is necessary to confirm these findings using larger samples with follow-up data for predictive validity. Such a questionnaire could be used by clinicians to identify high risk of patients and to design individualised education programme for PrU prevention
A simple proof of Duquesne's theorem on contour processes of conditioned Galton-Watson trees
We give a simple new proof of a theorem of Duquesne, stating that the
properly rescaled contour function of a critical aperiodic Galton-Watson tree,
whose offspring distribution is in the domain of attraction of a stable law of
index , conditioned on having total progeny , converges in
the functional sense to the normalized excursion of the continuous-time height
function of a strictly stable spectrally positive L\'evy process of index
. To this end, we generalize an idea of Le Gall which consists in using
an absolute continuity relation between the conditional probability of having
total progeny exactly and the conditional probability of having total
progeny at least . This new method is robust and can be adapted to establish
invariance theorems for Galton-Watson trees having vertices whose degrees
are prescribed to belong to a fixed subset of the positive integers.Comment: 16 pages, 2 figures. Published versio
Maximum likelihood drift estimation for a threshold diffusion
We study the maximum likelihood estimator of the drift parameters of a
stochastic differential equation, with both drift and diffusion coefficients
constant on the positive and negative axis, yet discontinuous at zero. This
threshold diffusion is called drifted Oscillating Brownian motion.For this
continuously observed diffusion, the maximum likelihood estimator coincide with
a quasi-likelihood estimator with constant diffusion term. We show that this
estimator is the limit, as observations become dense in time, of the
(quasi)-maximum likelihood estimator based on discrete observations. In long
time, the asymptotic behaviors of the positive and negative occupation times
rule the ones of the estimators. Differently from most known results in the
literature, we do not restrict ourselves to the ergodic framework: indeed,
depending on the signs of the drift, the process may be ergodic, transient or
null recurrent. For each regime, we establish whether or not the estimators are
consistent; if they are, we prove the convergence in long time of the properly
rescaled difference of the estimators towards a normal or mixed normal
distribution. These theoretical results are backed by numerical simulations
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