197,602 research outputs found
From the Body to the Inhabited Space (video)
No full textCo-produzione di film corto presentato al congresso SEAM, Sydney 2009 e allegato al testo A. COMO, Dal corpo allo spazio abitato / From the Body to the Inhabited Space, Aracne Editrice, Roma 2010, isbn 978-88-548-3283-1
Prolongation of TCD-enhanced Doppler signal by continuous infusion of Levovist
No full textThis study evaluated the effects of two different rates of infusion of echo-contrast agents (ECA) on signal enhancement. A total of 15 patients with insufficient Doppler signal due to inadequate transtemporal acoustic bone window were examined. Signal from the middle cerebral artery was recorded during the IV infusion of Levovist(R) (300 mg/mL). Increment of signal enhancement in dB, time to signal enhancement appearance, time to clinically useful signal enhancement appearance, and duration of clinically useful signal enhancement were assessed during two infusions at the rate of 1 and 0.66 mL/min, respectively. Increment of signal enhancement was similar at the rate of I and 0.66 mL/min (p = 0.4). Mean time to signal enhancement appearance and mean time to clinically useful signal enhancement appearance were not significantly different with the two rates of infusion (p = 0.9 and p = 0.3, respectively). Mean duration of clinically useful signal enhancement was significantly higher with the infusion rate of 0.66 mL/min as compared to 1 mL/min (p < 0.0001). Levovist(R) injected at the infusion rate of 0.66 mL/min prolonged the mean duration of signal enhancement, maintaining its effectiveness. (E-mail: [email protected]) (C) 2002 World Federation for Ultrasound in Medicine & Biology
SCOUT: A small vacuum chamber for nano-wire grid polarizer tests in the ultraviolet band
No full textWithin the Section of Astronomy of the Department of Physics and Astronomy of the University of Firenze (Italy), the XUVLab laboratory is active since 1998 dedicated to technological development, mainly UV oriented. The technological research is focused both on electronics and optics. Our last approach is dedicated to the development of innovative wiregrid polarizers optimized to work in transmission at 121.6 nm. The manufacturing of such optical devices requires advanced technological expertise and suitable experimental structures. First, nanotechnology capability is necessary, in order to build several tiny parallel conductive lines separated by tens of nanometers on wide areas to be macroscopically exploitable in an optical laboratory. Moreover, the characterization of such an advanced optical device has to be performed in vacuum, being air absorptive at 121.6 nm. A dedicated small vacuum chamber, SCOUT (Small Chamber for Optical UV Tests) was developed within our laboratory in order to perform practical and fast measurements. SCOUT hosts an optical bench and is equipped with several opening flanges, in order to be as flexible as possible. The flexibility that has been reached with SCOUT allows us to use the chamber beyond the goals it was thought for. It is exploitable by whatever compact (within 1 m) optical experiment that investigates the UV band of the spectrum. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
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La dimensione storica e teorica: la società civile nella filosofia politica e nella prassi
No full textPhoton transport with a localized source in locally convex spaces
No full textThis paper deals with the study of a mathematical model of photon transport in an interstellar cloud
where a localized source is present. The source is represented by a Dirac delta functional. The problem
is studied in the setting of locally convex spaces. By means of the theory of semigroups on locally
13 convex spaces and the adjoint approach, we prove existence and uniqueness of the solution
The Chapman-Enskog procedure for an age-structured population model: initial, boundary and corner layer corrections
No full textWe consider a mathematical model of an age-structured population of some fisheries (for example, anchovies, sardines or soles). Two time scales are involved in the problem: the fast time scale for the migration dynamics and the slow time scale for the demographic process. At a first step, we study the so called 'aggregated' system by means of the semigroups theory. Then, we study the asymptotic behaviour of the model by using the Chapman-Enskog procedure. In particular, we study initial, boundary and corner layer effects in order to obtain the exact initial and boundary conditions the approximated solution has to satisfy. (c) 2005 Elsevier Inc. All rights reserved
B-bounded nonlinear semigroups
No full textIn this paper we study the properties of a new one parameter family of nonlinear operators which is a generalization of B-bounded linear semigroups.
This family is constructed by means of a nonlinear operator A and a linear operator B.
We give also examples of problems which can be solved by using such a family
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