3,115 research outputs found
Hard exclusive photoproduction of and mesons
We present predictions for differential cross sections for the reaction
and give an outlook to which extent our calculations may
be generalized to the photoproduction of mesons. Our results are
obtained within perturbative QCD treating the proton as a quark-diquark system.Comment: 4 pages, 1 figure, uses Elsevier style espcrc1.st
Longitudinally Polarized Photoproduction of Inclusive Hadrons at Fixed-Target Experiments
We present a detailed phenomenological study of spin-dependent
single-inclusive high-p_T hadron photoproduction with particular emphasis on
the kinematics relevant for the Compass and Hermes fixed-target experiments. We
carefully examine the theoretical uncertainties associated with the only
moderate transverse momenta accessible in such measurements and analyze the
sensitivity of the relevant spin asymmetries to the gluon polarization in the
nucleon as well as to the completely unknown parton content of circularly
polarized photons.Comment: 12 pages, 14 figures; final version to appear in EPJC; comparison to
E155 data and references adde
The uniqueness of the solution of the Schrodinger equation with discontinuous coefficients
Consider the Schroeodinger equation: - Du(x) - l(x)u + s(x)u = 0, where D is
the Laplacian, l(x) > 0 and s(x) is dominated by l(x). We shall extend the
celebrated Kato's result on the asymptotic behavior of the solution to the case
where l(x) has unbounded discontinuity. The result will be used to establish
the limiting absorption principle for a class of reduced wave operators with
discontinuous coefficients.Comment: 29 (twenty-nine) pages; no figures; to appear in Reviews of
Mathematical Physic
Psychiatrische Versorgungsepidemiologie
Zusammenfassung: Psychiatrische Versorgungsepidemiologie untersucht die Situation der Versorgung von Menschen mit psychischen Erkrankungen unter Alltagsbedingungen. Psychiatrische Versorgungsstrukturen in Deutschland haben sich in den letzten Jahrzehnten weg von stationärer Behandlung mit teilweise mehrmonatiger Aufenthaltsdauer hin zu dezentralen teilstationären und ambulanten Angeboten entwickelt. Derzeit hat sich die Verschiebung von Behandlungskapazitäten zwischen den Settings stabilisiert und der Schwerpunkt der Versorgungsplanung liegt mehr auf der Entwicklung von möglichst flächendeckenden Strukturen zur Vernetzung der oftmals noch fragmentierten und streng an den Sektorgrenzen orientierten Versorgungslandschaft. Der Versorgungsbedarf hängt mit einer Vielzahl Faktoren wie den epidemiologischen Daten der Bevölkerung, der Inanspruchnahme und den gesundheitspolitischen Rahmenbedingungen zusammen. Ob die derzeitigen Versorgungsstrukturen den aktuellen Bedarf abdecken und den Qualitätsansprüchen genügen, ist aufgrund der spärlichen Datenlage und dem Mangel an Referenzmaßstäben nur schwer zu beurteilen. Ein substanzieller Ausbau psychiatrischer Versorgungsforschung in den kommenden Jahren ist hierfür grundlegend erforderlic
Global Regularity of Solution for General Degenerate Parabolic Equations in 1-D
AbstractThis paper considers the Cauchy problem for the general degenerate parabolic equations (1.1) with initial data (1.2). In the critical condition meas{u:g(u)=0{=0 we obtain the regular estimateG(u)∈C(1), whereG(u)=∫u0g(s)ds. A new maximum principle is introduced to obtain the estimate and is applied to some special equations such as prous media equation, an infiltration equation to obtain the optimal estimate |(um−1)x|⩽M. Finally an interesting equation related to the Broadwell model (whereg(u) has two zero points) is studied and a uniquely regular solutionu∈C(1)is obtained. Moreover the estimatesux⩽ρ(f(u)−u2)/g(u) andρ⩾infxρ0(x)/(1+4t(infxρ0(x))) are proved for the solution of the Navier–Stokes equations corresponding to the Broadwell model
A priori convergence estimates for a rough Poisson-Dirichlet problem with natural vertical boundary conditions
Stents are medical devices designed to modify blood flow in aneurysm sacs, in
order to prevent their rupture. Some of them can be considered as a locally
periodic rough boundary. In order to approximate blood flow in arteries and
vessels of the cardio-vascular system containing stents, we use multi-scale
techniques to construct boundary layers and wall laws. Simplifying the flow we
turn to consider a 2-dimensional Poisson problem that conserves essential
features related to the rough boundary. Then, we investigate convergence of
boundary layer approximations and the corresponding wall laws in the case of
Neumann type boundary conditions at the inlet and outlet parts of the domain.
The difficulty comes from the fact that correctors, for the boundary layers
near the rough surface, may introduce error terms on the other portions of the
boundary. In order to correct these spurious oscillations, we introduce a
vertical boundary layer. Trough a careful study of its behavior, we prove
rigorously decay estimates. We then construct complete boundary layers that
respect the macroscopic boundary conditions. We also derive error estimates in
terms of the roughness size epsilon either for the full boundary layer
approximation and for the corresponding averaged wall law.Comment: Dedicated to Professor Giovanni Paolo Galdi 60' Birthda
2D velocity fields of simulated interacting disc galaxies
We investigate distortions in the velocity fields of disc galaxies and their
use to reveal the dynamical state of interacting galaxies at different
redshift. For that purpose, we model disc galaxies in combined
N-body/hydrodynamic simulations. 2D velocity fields of the gas are extracted
from these simulations which we place at different redshifts from z=0 to z=1 to
investigate resolution effects on the properties of the velocity field. To
quantify the structure of the velocity field we also perform a kinemetry
analysis. If the galaxy is undisturbed we find that the rotation curve
extracted from the 2D field agrees well with long-slit rotation curves. This is
not true for interacting systems, as the kinematic axis is not well defined and
does in general not coincide with the photometric axis of the system. For large
(Milky way type) galaxies we find that distortions are still visible at
intermediate redshifts but partly smeared out. Thus a careful analysis of the
velocity field is necessary before using it for a Tully-Fisher study. For small
galaxies (disc scale length ~2 kpc) even strong distortions are not visible in
the velocity field at z~0.5 with currently available angular resolution.
Therefore we conclude that current distant Tully-Fisher studies cannot give
reliable results for low-mass systems. Additionally to these studies we confirm
the power of near-infrared integral field spectrometers in combination with
adaptive optics (such as SINFONI) to study velocity fields of galaxies at high
redshift (z~2).Comment: 12 pages, 18 figures, accepted for publication in A&A, high
resolution version can be found at
http://astro.uibk.ac.at/~thomas/kronberger.pd
Realization of a semiconductor-based cavity soliton laser
The realization of a cavity soliton laser using a vertical-cavity
surface-emitting semiconductor gain structure coupled to an external cavity
with a frequency-selective element is reported. All-optical control of bistable
solitonic emission states representing small microlasers is demonstrated by
injection of an external beam. The control scheme is phase-insensitive and
hence expected to be robust for all-optical processing applications. The
motility of these structures is also demonstrated
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