4,182 research outputs found
Prognostic factors for corneal graft recovery after severe corneal graft rejection following penetrating keratoplasty
BACKGROUND: To investigate the outcome and prognostic factors for corneal graft recovery after severe corneal graft rejection following penetrating keratoplasty (PKP) treated with topical and systemic steroids. METHODS: Fifty-eight eyes in 58 patients with severe corneal graft rejection following PKP were treated with topical and systemic steroids. Factors affecting the reversibility and maintenance of graft transparency were analyzed. RESULTS: Graft transparency was restored in 37 of 58 eyes (63.8%). Clarity of the graft was maintained in 25 of 37 eyes after transparency was restored, while corneal decompensation developed at a mean of 6.0 ± 4.3 months in the remainder. The interval between rejection and treatment with systemic steroids was shorter in cases that recovered graft transparency (OR, 0.88, 95% CI. 0.80–0.97, P = 0.0093). Corneal decompensation after the recovery of corneal transparency tend to occur in cases of regraft (OR, 0.09, 95% CI. 0.01–0.54, P = 0.0091). CONCLUSIONS: Severe corneal graft rejection after PKP was reversible in approximately two-thirds of the cases, with graft transparency being maintained in two-thirds of them when treated with both topical and systemic steroids. Early treatment confers a benefit in terms of the recovery of graft transparency
Detailed study of B037 based on {\sl HST} images
B037 is of interest because it is both the most luminous and the most highly
reddened cluster known in M31. Images of deep observations and of highly
spatial resolutions with the Advanced Camera for Surveys on the {\sl HST}
firstly show that this cluster is crossed by a dust lane. Photometric data in
the F606W and F814W filters obtained in this paper provide that, colors of
() in the dust lane are redder mags than ones in
the other regions of B037. The {\sl HST} images show that, this dust lane seems
to be contained in B037, not from the M31 disk or the Milky Way. As we know,
the formation of dust requires gas with a rather high metallicity. However,
B037 has a low metallicity to be . So, it seems
improbable that the observed dust lane is physically associated with B037. It
is clear that the origin of this dust lane is worthy of future study. In
addition, based on these images, we present the precise variation of
ellipticity and position angle, and of surface brightness profile, and
determine the structural parameters of B037 by fitting a single-mass isotropic
King model. In the F606W filter, we derive the best-fitting scale radius,
r_0=0.56\pm0.02\arcsec~(=2.16\pm0.08~\rm{pc}), a tidal radius,
r_t=8.6\pm0.4\arcsec~(=33.1\pm1.5~\rm{pc}), and a concentration index . In the F814W filter, we derive
r_0=0.56\pm0.01\arcsec~(=2.16\pm0.04~\rm{pc}),
r_t=8.9\pm0.3\arcsec~(=34.3\pm1.2~\rm{pc}), and . The extinction-corrected central surface brightness is
in the F606W filter, and in the F814W filter, respectively.Comment: Accepted for Publication in RAA, 13 pages, 5 figures and 7 table
A Two-stage Method for Inverse Medium Scattering
We present a novel numerical method to the time-harmonic inverse medium
scattering problem of recovering the refractive index from near-field scattered
data. The approach consists of two stages, one pruning step of detecting the
scatterer support, and one resolution enhancing step with mixed regularization.
The first step is strictly direct and of sampling type, and faithfully detects
the scatterer support. The second step is an innovative application of
nonsmooth mixed regularization, and it accurately resolves the scatterer sizes
as well as intensities. The model is efficiently solved by a semi-smooth
Newton-type method. Numerical results for two- and three-dimensional examples
indicate that the approach is accurate, computationally efficient, and robust
with respect to data noise.Comment: 18 pages, 5 figure
Local moment formation in zinc doped cuprates
We suggest that when zinc is substituted for copper in the copper oxide
planes of high superconductors, it does not necessarily have a valency
of 2+. Rather, the valency of a zinc impurity should be determined by its
surrounding medium. In order to study this hypothesis, we examine the effect of
static impurities inducing diagonal disorder within a one band Hubbard model
coupled to a localised state. We use this model to discuss the physics of zinc
doping in the cuprates. Specifically, we discuss the formation of local moments
near impurity sites and the modification of the transverse spin susceptibility
in the antiferromagnetic state.Comment: 7 pages RevTex, includes 4 figure
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Genetic variation in the SIM1 locus is associated with erectile dysfunction.
Erectile dysfunction affects millions of men worldwide. Twin studies support the role of genetic risk factors underlying erectile dysfunction, but no specific genetic variants have been identified. We conducted a large-scale genome-wide association study of erectile dysfunction in 36,649 men in the multiethnic Kaiser Permanente Northern California Genetic Epidemiology Research in Adult Health and Aging cohort. We also undertook replication analyses in 222,358 men from the UK Biobank. In the discovery cohort, we identified a single locus (rs17185536-T) on chromosome 6 near the single-minded family basic helix-loop-helix transcription factor 1 (SIM1) gene that was significantly associated with the risk of erectile dysfunction (odds ratio = 1.26, P = 3.4 × 10-25). The association replicated in the UK Biobank sample (odds ratio = 1.25, P = 6.8 × 10-14), and the effect is independent of known erectile dysfunction risk factors, including body mass index (BMI). The risk locus resides on the same topologically associating domain as SIM1 and interacts with the SIM1 promoter, and the rs17185536-T risk allele showed differential enhancer activity. SIM1 is part of the leptin-melanocortin system, which has an established role in body weight homeostasis and sexual function. Because the variants associated with erectile dysfunction are not associated with differences in BMI, our findings suggest a mechanism that is specific to sexual function
Optimization viewpoint on Kalman smoothing, with applications to robust and sparse estimation
In this paper, we present the optimization formulation of the Kalman
filtering and smoothing problems, and use this perspective to develop a variety
of extensions and applications. We first formulate classic Kalman smoothing as
a least squares problem, highlight special structure, and show that the classic
filtering and smoothing algorithms are equivalent to a particular algorithm for
solving this problem. Once this equivalence is established, we present
extensions of Kalman smoothing to systems with nonlinear process and
measurement models, systems with linear and nonlinear inequality constraints,
systems with outliers in the measurements or sudden changes in the state, and
systems where the sparsity of the state sequence must be accounted for. All
extensions preserve the computational efficiency of the classic algorithms, and
most of the extensions are illustrated with numerical examples, which are part
of an open source Kalman smoothing Matlab/Octave package.Comment: 46 pages, 11 figure
The Devil is in the Details: Compact Structures in Pulsar Wind Nebulae
The large-scale structure of pulsar wind nebulae (PWNe) tells us a
considerable amount about their average magnetic fields, the total particle
input from the pulsar winds, and the confining pressure at their outer
boundaries. However, the details of the pulsar outflow, the sites of shocks and
particle acceleration, the effects of instabilities in the magnetic field, and
the interaction between the relativistic wind and the surrounding ejecta are
contained in small-scale structures, where we observe jets and toroidal
structures, time-varying emission from compact clumps, and filaments in both
the inner and outer regions of the nebulae. Here I review recent observational
studies of compact structures in PWNe and present current scenarios (and
questions) regarding their origin.Comment: 13 pages, 4 embedded EPS figures. Advances in Space Research, in
pres
Collaborative roles of Temporoparietal Junction and Dorsolateral Prefrontal Cortex in Different Types of Behavioural Flexibility
Behavioural flexibility is essential for everyday life. This involves shifting attention between different perspectives. Previous studies suggest that flexibility is mainly subserved by the dorsolateral prefrontal cortex (DLPFC). However, although rarely emphasized, the temporoparietal junction (TPJ) is frequently recruited during flexible behaviour. A crucial question is whether TPJ plays a role in different types of flexibility, compared to its limited role in perceptual flexibility. We hypothesized that TPJ activity during diverse flexibility tasks plays a common role in stimulus-driven attention-shifting, thereby contributing to different types of flexibility, and thus the collaboration between DLPFC and TPJ might serve as a more appropriate mechanism than DLPFC alone. We used fMRI to measure DLPFC/TPJ activity recruited during moral flexibility, and examined its effect on other domains of flexibility (economic/perceptual). Here, we show the additional, yet crucial role of TPJ: a combined DLPFC/TPJ activity predicted flexibility, regardless of domain. Different types of flexibility might rely on more basic attention-shifting, which highlights the behavioural significance of alternatives.Peer reviewe
Smoking cessation during pregnancy: the influence of partners, family and friends on quitters and non-quitters
This research compared pregnant quitters’ and non-quitters’ accounts of how partners, family and friends influenced their smoking cessation attempts. Qualitative secondary data analysis was carried out on a purposive sample of motivational interview transcripts undertaken by research midwives with pregnant women as part of SmokeChange, a smoking cessation intervention. Interviews with all quitters in the intervention group (n = 12) were analysed comparatively with interviews from a matched sample of non-quitters (n = 12).The discourses of both revealed similarity in how their partners, family and friends influenced their cessation efforts: salient others were simultaneously perceived by both groups of women as providing drivers and barriers to quit attempts; close associates who smoked were often perceived to be as supportive as those who did not. However, women who quit smoking during pregnancy talked more about receiving active praise/encouragement than those who did not. While close associates play an important role in women’s attempts to stop smoking during pregnancy, the support they provide varies; further research is needed to develop a better understanding of how key relationships help or hinder cessation during pregnancy
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