1,579 research outputs found
A general resonance theory based on Mourre's inequality
We study the perturbation of bound states embedded in the continuous spectrum
which are unstable by the Fermi Golden Rule. The approach to resonance theory
based on spectral deformation is extended to a more general class of quantum
systems characterized by Mourre's inequality and smoothness of the resolvent.
Within the framework of perturbation theory it is still possible to give a
definite meaning to the notion of complex resonance energies and of
corresponding metastable states. The main result is a quasi-exponential decay
estimate up to a controlled error of higher order in perturbation theory.Comment: 17 page
Using tensor properties of four wave mixing in semiconductor optical amplifiers for polarization independent wavelength conversion or pump suppression
Summary form only given. Wavelength conversion by four-wave mixing (FWM) in semiconductor optical amplifiers (SOAs) has several advantages, including transparency to the modulation format and bit rate. An important feature of the intensity and polarization of the FWM wavelength-converted signal is their dependence on the polarizations of the input signal and pump waves. In this paper, we discuss the polarization properties of the FWM susceptibility χ_(ijkl) of strained multiple quantum well SOAs and their potential for application to polarization-independent wavelength conversion and pump suppression
Limiting absorption principle and perfectly matched layer method for Dirichlet Laplacians in quasi-cylindrical domains
We establish a limiting absorption principle for Dirichlet Laplacians in
quasi-cylindrical domains. Outside a bounded set these domains can be
transformed onto a semi-cylinder by suitable diffeomorphisms. Dirichlet
Laplacians model quantum or acoustically-soft waveguides associated with
quasi-cylindrical domains. We construct a uniquely solvable problem with
perfectly matched layers of finite length. We prove that solutions of the
latter problem approximate outgoing or incoming solutions with an error that
exponentially tends to zero as the length of layers tends to infinity. Outgoing
and incoming solutions are characterized by means of the limiting absorption
principle.Comment: to appear in SIAM Journal on Mathematical Analysi
Canonical Expansion of PT-Symmetric Operators and Perturbation Theory
Let be any \PT symmetric Schr\"odinger operator of the type on , where is
any odd homogeneous polynomial and . It is proved that is
self-adjoint and that its eigenvalues coincide (up to a sign) with the singular
values of , i.e. the eigenvalues of . Moreover we
explicitly construct the canonical expansion of and determine the singular
values of through the Borel summability of their divergent
perturbation theory. The singular values yield estimates of the location of the
eigenvalues \l_j of by Weyl's inequalities.Comment: 20 page
Fire-cracked Rock Use and Reuse in the Hueco Bolson, Fort Bliss, Texas
The Center for Archaeological Research of The University of Texas at San Antonio conducted an analysis of 29,058 pieces of fire-cracked rock and burned caliche selected from a sample of hundreds of features tested as part of the Hueco Mountain Archaeological Project at Fort Bliss, Texas. Feature and non-feature material included in this analysis were collected from site FB 13237 located on the proximal fan, FB 12719 within the basin area, and FB 12412 situated in the transitional zone between the two.
The goal of the analysis was to identify patterns of attribute variability in burned rock that could be used to infer function of the various features and sites in the sample. Specific burned rock attributes used in the study were material type, size, weight, and the presence or absence of fracturing, cortex, and discoloration. These attributes were recorded and compared in various combinations at course- and fme-grained levels of intensity to address issues of reuse, recycling, feature function, thermally induced morphological variability, and how these variables might relate to specific land forms through time.
Through these comparisons, patterns relating to expedient material selection, feature type, reuse and feature function were identified
Der internistische Check-up
Zusammenfassung: Viele präventive Maßnahmen bei gesunden Erwachsenen werden in zunehmendem Maße durch Evidenz gestützt oder verworfen. Dabei sind v.a. die Beratung bezüglich Tabakabstinenz, indizierte Impfungen und das Screening in Bezug auf Übergewicht, hohen Blutdruck, Hyperlipidämie, Zervixkarzinom, kolorektales Karzinom und Mammakarzinom bewiesenermaßen wichtig und sinnvoll. Nicht empfohlen wird ein Screening für Bronchial-, Pankreas- und Ovarialkarzinom. Ein Screening für Diabetes mellitus beim jüngeren Erwachsenen, Schilddrüsenerkrankungen und Prostatakarzinom wird nicht routinemäßig empfohlen, sollte aber je nach persönlichem Risikoprofil im Sinne eines sog. "Case findings" erwogen werden. Aus ärztlicher Sicht ist es auch wichtig, auf mögliche nicht deklarierte Beweggründe für eine Check-up-Untersuchung einzugehen, um so mögliche "Hidden Agendas" der Konsultationen aufzudecke
Integrating Data on Ethnicity, Geography, and Conflict: The Ethnic Power Relations Dataset Family.
ArticleThis article introduces the new Family of Ethnic Power Relations (EPR) data sets, version 2014, which is the latest in a series of data sets on ethnicity that have stimulated civil war research in the past decade. The EPR Family provides data on ethnic groups’ access to state power, their settlement patterns, links to rebel organizations, transborder ethnic kin relations, and intraethnic cleavages. The new 2014 version does not only extend the data set’s temporal coverage from 2009 to 2013, but it also offers several new features, such as a new measure of regional autonomy that is independent of national-level executive power and a new data set component coding intraethnic identities and cleavages. Moreover, for the first time, detailed documentation of the EPR data is provided through the EPR Atlas. This article presents these novelties in detail and compares the EPR Family 2014 to the most relevant alternative data sets on ethnicity.Swiss National Science FoundationSwiss Agency for Development and Cooperation (SDC
28-jähriger Patient mit erfolgreich behandelter dilatativer Kardiomyopathie
Zusammenfassung: Ein 28-jähriger Patient wurde mit dekompensierter Herzinsuffizienz notfallmäßig zugewiesen. In der Vorgeschichte bestand ein hypogonadotroper Hypogonadismus. Echokardiographisch fand sich eine dilatative Kardiomyopathie. Ein erhöhtes Serumferritin und eine Eisenüberladung in der Leberbiopsie ließen eine hereditäre Hämochromatose vermuten. Die kardiale Beteiligung konnte mittels Magnetresonanztomographie nachgewiesen werden. Genetische Abklärungen ergaben eine homozygote Mutation für G320V und bewiesen eine juvenile Hämochromatose. Eine Aderlasstherapie führte innerhalb eines Jahres zur Normalisierung des Eisenstatus und der kardialen Pumpfunktio
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