4,572 research outputs found
Incidental finding of a microsporidian parasite from an AIDS patient
Light microscopic examination of feces from a human immunodeficiency virus-positive patient with chronic diarrhea, anorexia, and lethargy revealed the presence of numerous refractile bodies resembling microsporidian spores. They were subsequently identified as belonging to the genus Nosema on the basis of their ultrastructural characteristics. However, the microsporidia were enclosed within striated muscle cells, suggesting that they were probably ingested in food; thus, this represented an incidental finding rather than a true infection
On the uncertainty relations and squeezed states for the quantum mechanics on a circle
The uncertainty relations for the position and momentum of a quantum particle
on a circle are identified minimized by the corresponding coherent states. The
sqeezed states in the case of the circular motion are introduced and discussed
in the context of the uncertainty relations.Comment: 4 figure
Calibrated Sub-Bundles in Non-Compact Manifolds of Special Holonomy
This paper is a continuation of math.DG/0408005. We first construct special
Lagrangian submanifolds of the Ricci-flat Stenzel metric (of holonomy SU(n)) on
the cotangent bundle of S^n by looking at the conormal bundle of appropriate
submanifolds of S^n. We find that the condition for the conormal bundle to be
special Lagrangian is the same as that discovered by Harvey-Lawson for
submanifolds in R^n in their pioneering paper. We also construct calibrated
submanifolds in complete metrics with special holonomy G_2 and Spin(7)
discovered by Bryant and Salamon on the total spaces of appropriate bundles
over self-dual Einstein four manifolds. The submanifolds are constructed as
certain subbundles over immersed surfaces. We show that this construction
requires the surface to be minimal in the associative and Cayley cases, and to
be (properly oriented) real isotropic in the coassociative case. We also make
some remarks about using these constructions as a possible local model for the
intersection of compact calibrated submanifolds in a compact manifold with
special holonomy.Comment: 20 pages; for Revised Version: Minor cosmetic changes, some
paragraphs rewritten for improved clarit
Metastable Vacua and the Backreacted Stenzel Geometry
We construct an M-theory background dual to the metastable state recently
discussed by Klebanov and Pufu, which corresponds to placing a stack of anti-M2
branes at the tip of a warped Stenzel space. With this purpose we analytically
solve for the linearized non-supersymmetric deformations around the warped
Stenzel space, preserving the SO(5) symmetries of the supersymmetric
background, and which interpolate between the IR and UV region. We identify the
supergravity solution which corresponds to a stack of backreacting
anti-M2 branes by fixing all the 12 integration constants in terms of
. While in the UV this solution has the desired features to describe
the conjectured metastable state of the dual (2+1)-dimensional theory, in the
IR it suffers from a singularity in the four-form flux, which we describe in
some details.Comment: 33 pages, 3 figure
Linear Response Calculations of Spin Fluctuations
A variational formulation of the time--dependent linear response based on the
Sternheimer method is developed in order to make practical ab initio
calculations of dynamical spin susceptibilities of solids. Using gradient
density functional and a muffin-tin-orbital representation, the efficiency of
the approach is demonstrated by applications to selected magnetic and strongly
paramagnetic metals. The results are found to be consistent with experiment and
are compared with previous theoretical calculations.Comment: 11 pages, RevTex; 3 Figures, postscript, high-resolution printing
(~1200dpi) is desire
Spatial modeling of the 3D morphology of hybrid polymer-ZnO solar cells, based on electron tomography data
A spatial stochastic model is developed which describes the 3D nanomorphology
of composite materials, being blends of two different (organic and inorganic)
solid phases. Such materials are used, for example, in photoactive layers of
hybrid polymer zinc oxide solar cells. The model is based on ideas from
stochastic geometry and spatial statistics. Its parameters are fitted to image
data gained by electron tomography (ET), where adaptive thresholding and
stochastic segmentation have been used to represent morphological features of
the considered ET data by unions of overlapping spheres. Their midpoints are
modeled by a stack of 2D point processes with a suitably chosen correlation
structure, whereas a moving-average procedure is used to add the radii of
spheres. The model is validated by comparing physically relevant
characteristics of real and simulated data, like the efficiency of exciton
quenching, which is important for the generation of charges and their transport
toward the electrodes.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS468 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
QCD
We discuss issues of QCD at the LHC including parton distributions, Monte
Carlo event generators, the available next-to-leading order calculations,
resummation, photon production, small x physics, double parton scattering, and
backgrounds to Higgs production.Comment: 115 pages, Latex, 47 figures, to appear in the Report of the ``1999
CERN Workshop on SM Physics (and more) at the LHC'', S. Catani, M. Dittmar,
D. Soper, W.J. Stirling, S. Tapprogge (convenors
Graph-based simulated annealing: a hybrid approach to stochastic modeling of complex microstructures
A stochastic model is proposed for the efficient simulation of complex three-dimensional microstructures consisting of two different phases. The model is based on a hybrid approach, where in a first step a graph model is developed using ideas from stochastic geometry. Subsequently, the microstructure model is built by applying simulated annealing to the graph model. As an example of application, the model is fitted to a tomographic image describing the microstructure of electrodes in Li-ion batteries. The goodness of model fit is validated by comparing morphological characteristics of experimental and simulated data
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