1,635 research outputs found
Estimation of fluence rate and absorbed dose rate due to gas bremsstrahlung from electron storage rings
Abstract Bremsstrahlung produced in electron storage rings by interactions with residual gas has been studied in the energy range 100–1000 MeV using the PLUKA code. Photon spectra and quantitative estimates of fluence rate and tissue absorbed dose rate are given. Simple equations are proposed for the fluence rate and the absorbed dose rate according to the results obtained
Symmetrization Techniques in Image Deblurring
This paper presents a couple of preconditioning techniques that can be used
to enhance the performance of iterative regularization methods applied to image
deblurring problems with a variety of point spread functions (PSFs) and
boundary conditions. More precisely, we first consider the anti-identity
preconditioner, which symmetrizes the coefficient matrix associated to problems
with zero boundary conditions, allowing the use of MINRES as a regularization
method. When considering more sophisticated boundary conditions and strongly
nonsymmetric PSFs, the anti-identity preconditioner improves the performance of
GMRES. We then consider both stationary and iteration-dependent regularizing
circulant preconditioners that, applied in connection with the anti-identity
matrix and both standard and flexible Krylov subspaces, speed up the
iterations. A theoretical result about the clustering of the eigenvalues of the
preconditioned matrices is proved in a special case. The results of many
numerical experiments are reported to show the effectiveness of the new
preconditioning techniques, including when considering the deblurring of sparse
images
Intermuscular pocket for subcutaneous implantable cardioverter defibrillator: Single-center experience
AbstractThe subcutaneous implantable cardioverter defibrillator (S-ICD) is a novel device now accepted in clinical practice for treating ventricular arrhythmias. In 14 consecutive patients, S-ICD devices were placed in the virtual space between the anterior surface of the serratus anterior muscle and the posterior surface of the latissimus dorsi muscle. During a mean follow up of 9 months, no dislocations, infections, hematoma formations, or skin erosions were observed. Intermuscular implantation of the S-ICD could be a reliable, safe, and appealing alternative to the standard subcutaneous placement
The Rare Book Collection of the Library of the Italian National Institute of Health: from the past to the present
The Library of the Istituto Superiore di Sanità (ISS), the Italian National Institute of Health, is the main library for public health and biomedical research in Italy and holds a small but valuable special collection of ancient books. Known as the Rare Book Collection, this fund consists of over 1200 scientific printed volumes published between the XVI and the XIX century. The purpose of this paper is to illustrate the challenges and the process undertaken by the Library to share and digitalize this Collection
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