Boundary regularity for the Poisson equation in reifenberg-flat domains

This paper is devoted to the investigation of the boundary regularity for the Poisson equation {{cc} -\Delta u = f & \text{in} \Omega u= 0 & \text{on} \partial \Omega where $f$ belongs to some $L^p(\Omega)$ and $\Omega$ is a Reifenberg-flat domain of $\mathbb R^n.$ More precisely, we prove that given an exponent $\alpha\in (0,1)$, there exists an $\varepsilon>0$ such that the solution $u$ to the previous system is locally H\"older continuous provided that $\Omega$ is $(\varepsilon,r_0)$-Reifenberg-flat. The proof is based on Alt-Caffarelli-Friedman's monotonicity formula and Morrey-Campanato theorem

“-itis & -itis”: Immune Checkpoint Inhibitors Toxicity Management

https://digitalcommons.psjhealth.org/other_pubs/1080/thumbnail.jp

Are spiral galaxies optically thin or thick?

The opacity of spiral galaxies is examined by modelling the dust and stellar content of individual galaxies. The model is applied to five late-type spiral galaxies (NGC 4013, IC 2531, UGC 1082, NGC 5529 and NGC 5907). Having analyzed a total of seven galaxies thus far, the five galaxies mentioned above plus UGC 2048 and NGC 891 presented in (Xilouris et al. 1997, 1998), we are able to draw some general conclusions, the most significant of which are: 1) The face-on central optical depth is less than one in all optical bands indicating that typical spiral galaxies like the ones that we have modelled would be completely transparent if they were to be seen face-on. 2) The dust scaleheight is about half that of the stars, which means that the dust is more concentrated near the plane of the disk. 3) The dust scalelength is about 1.4 times larger than that of the stars and the dust is more radially extended than the stars. 4) The dust mass is found to be about an order of a magnitude more than previously measured using the IRAS fluxes, indicating the existence of a cold dust component. The gas-to-dust mass ratio calculated is close to the value derived for our Galaxy. 5) The derived extinction law matches quite well the Galactic extinction law, indicating a universal dust behaviour.Comment: 13 pages. Accepted for publication in A&

Scaling laws for the photo-ionisation cross section of two-electron atoms

The cross sections for single-electron photo-ionisation in two-electron atoms show fluctuations which decrease in amplitude when approaching the double-ionisation threshold. Based on semiclassical closed orbit theory, we show that the algebraic decay of the fluctuations can be characterised in terms of a threshold law $\sigma \propto |E|^{\mu}$ as $E \to 0_-$ with exponent $\mu$ obtained as a combination of stability exponents of the triple-collision singularity. It differs from Wannier's exponent dominating double ionisation processes. The details of the fluctuations are linked to a set of infinitely unstable classical orbits starting and ending in the non-regularisable triple collision. The findings are compared with quantum calculations for a model system, namely collinear helium.Comment: 4 pages, 1 figur

An Atlas of Monte Carlo Models of Dust Extinction in Galaxies for Cosmological Applications

We present an extensive study of the radiative transfer in dusty galaxies based on Monte Carlo simulations. The main output of these simulations are the attenuation curves ${\cal A}_\lambda$ (i.e. the ratio between the observed, dust extinguished, total intensity to the intrinsic unextinguished one of the galaxy as a function of wavelength). We have explored the dependence of ${\cal A}_\lambda$ on a conspicuous set of quantities (Hubble type, inclination, dust optical thickness, dust distribution and extinction properties) for a large wavelength interval, ranging from 1250\AA to the K band, thus finally providing a comprehensive atlas of dust extinction in galaxies, which is electronically available. This study is particularly suitable for inclusion into galaxy formation evolution models and to directly interpret observational data on high redshift galaxies.Comment: 29 pages, aasms4.sty, LaTeX, 5 figures. ApJSS, accepte

Psychometric properties of the Caregiver Preparedness Scale in caregivers of stroke survivors

Objective: To evaluate the psychometric characteristics of the Caregiver Preparedness Scale (CPS) in caregivers of stroke survivors. Background: Caregiver preparedness can have an important impact on both the caregiver and the stroke survivor. The validity and reliability of the CPS has not been tested for the stroke-caregiver population. Methods: We used a cross-sectional design to study a sample of 156 caregivers of stroke survivors. Construct validity of the CPS was evaluated by confirmatory factor analysis (CFA). Internal consistency and test-retest reliability were also evaluated. Results: Caregivers were, on average, 54 year old (SD ¼ 13.2) and most were women (64.7%). CFA supported the unidimensionality of the scale (comparative fit index ¼ 0.98). Reliability was also supported: item-reliability index and itemetotal correlations above 0.30; composite reliability index ¼ 0.93; Cronbach’s alpha ¼ 0.94; factor score determinacy ¼ 0.97; and test-retest reliability ¼ 0.92. Conclusion: The CPS is valid and reliable in caregivers of stroke survivors. Scores on this scale may assist health-care providers in identifying caregivers with less preparedness to provide specific interventions

Fracture Density Estimation Using Spectral Analysis of Reservoir Reflections: A Numerical Modeling Approach

We use a 3-D finite difference numerical model to generate synthetic seismograms from a simple fractured reservoir containing evenly spaced, discrete, vertical fractures. The fractures are represented using a single column of anisotropic grid points. Analysis of seismic amplitudes and spectral characteristics were carried out on the top and base reservoir reflections as well as scattered wave coda for models with fracture spacing ranging from 0.01 to 0.1 fractures/m. Results show that the bulk scattered wave energy contained in a common shot gather increases greatly when the fracture spacing is greater than about 1/4 wavelength. Wavenumber spectra for integrated amplitude versus offset from a time window containing the base reservoir reflector show spectral peaks corresponding to the fracture spacing.United States. Dept. of Energy (Grant DE-FC26-02NT15346)Massachusetts Institute of Technology. Earth Resources LaboratoryEni S.p.A. (Firm

A 60 pc counter-rotating core in NGC 4621

We present adaptive optics assisted OASIS integral field spectrography of the S0 galaxy NGC 4621. Two-dimensional stellar kinematical maps (mean velocity and dispersion) reveal the presence of a 60 pc diameter counter-rotating core (CRC), the smallest observed to date. The OASIS data also suggests that the kinematic center of the CRC is slightly offset from the center of the outer isophotes. This seems to be confirmed by archival HST/STIS data. We also present the HST/WFPC2 V-I colour map, which exhibits a central elongated red structure, also slightly off-centered in the same direction as the kinematic centre. We then construct an axisymmetric model of NGC 4621: the two-integral distribution function is derived using the Multi-Gaussian Expansion and the Hunter & Qian (1993) formalisms. Although the stellar velocities are reasonably fitted, including the region of the counter-rotating core, significant discrepancies between the model and the observations demonstrate the need for a more general model (e.g. a three-integral model).Comment: 9 pages, 8 figure