18,749 research outputs found
The Monte Carlo Event Generator DPMJET-III
A new version of the Monte Carlo event generator DPMJET is presented. It is a
code system based on the Dual Parton Model and unifies all features of the
DTUNUC-2, DPMJET-II and PHOJET 1.12 event generators. DPMJET-III allows the
simulation of hadron-hadron, hadron-nucleus, nucleus-nucleus, photon-hadron,
photon-photon and photon-nucleus interactions from a few GeV up to the highest
cosmic ray energies.Comment: 6 pages, Talk given at the Conference ``Monte Carlo 2000'', Lisbon,
Portugal, 23-26 Oct. 200
Compressible primitive equation: formal derivation and stability of weak solutions
We present a formal derivation of a simplified version of Compressible
Primitive Equations (CPEs) for atmosphere modeling. They are obtained from
-D compressible Navier-Stokes equations with an \emph{anisotropic viscous
stress tensor} where viscosity depends on the density. We then study the
stability of the weak solutions of this model by using an intermediate model,
called model problem, which is more simple and practical, to achieve the main
result
Persistent Homology Over Directed Acyclic Graphs
We define persistent homology groups over any set of spaces which have
inclusions defined so that the corresponding directed graph between the spaces
is acyclic, as well as along any subgraph of this directed graph. This method
simultaneously generalizes standard persistent homology, zigzag persistence and
multidimensional persistence to arbitrary directed acyclic graphs, and it also
allows the study of more general families of topological spaces or point-cloud
data. We give an algorithm to compute the persistent homology groups
simultaneously for all subgraphs which contain a single source and a single
sink in arithmetic operations, where is the number of vertices in
the graph. We then demonstrate as an application of these tools a method to
overlay two distinct filtrations of the same underlying space, which allows us
to detect the most significant barcodes using considerably fewer points than
standard persistence.Comment: Revised versio
Combinatorial RNA Design: Designability and Structure-Approximating Algorithm
In this work, we consider the Combinatorial RNA Design problem, a minimal
instance of the RNA design problem which aims at finding a sequence that admits
a given target as its unique base pair maximizing structure. We provide
complete characterizations for the structures that can be designed using
restricted alphabets. Under a classic four-letter alphabet, we provide a
complete characterization of designable structures without unpaired bases. When
unpaired bases are allowed, we provide partial characterizations for classes of
designable/undesignable structures, and show that the class of designable
structures is closed under the stutter operation. Membership of a given
structure to any of the classes can be tested in linear time and, for positive
instances, a solution can be found in linear time. Finally, we consider a
structure-approximating version of the problem that allows to extend bands
(helices) and, assuming that the input structure avoids two motifs, we provide
a linear-time algorithm that produces a designable structure with at most twice
more base pairs than the input structure.Comment: CPM - 26th Annual Symposium on Combinatorial Pattern Matching, Jun
2015, Ischia Island, Italy. LNCS, 201
Effects of Multi-Surface Modification on Curie temperature of ferroelectric films
Within the framework of mean field theory, we study the effects of
multi-surface modification on Curie temperature of ferroelectric films using
the transverse Ising model. The general nonlinear equations for Curie
temperature of multi-surface ferroelectric films with arbitrary exchange
constants and transverse fields are derived by the transfer matrix method. As
an example, we consider a film consisting of top surface layers, bulk layers
and bottom surface layers. Two types of surface modifications, modifications of
a surface exchange constant and a surface transverse field are taken into
account. The dependence of Curie temperature on the surface layer numbers, bulk
layer numbers, surface exchange constants, surface transverse fields and bulk
transverse fields is discussed.Comment: 11 pages, 5 figure
Antenatal atazanavir: a retrospective analysis of pregnancies exposed to atazanavir.
INTRODUCTION: There are few data regarding the tolerability, safety, or efficacy of antenatal atazanavir. We report our clinical experience of atazanavir use in pregnancy.
METHODS: A retrospective medical records review of atazanavir-exposed pregnancies in 12 London centres between 2004 and 2010.
RESULTS: There were 145 pregnancies in 135 women: 89 conceived whilst taking atazanavir-based combination antiretroviral therapy (cART), "preconception" atazanavir exposure; 27 started atazanavir-based cART as "first-line" during the pregnancy; and 29 "switched" to an atazanavir-based regimen from another cART regimen during pregnancy. Gastrointestinal intolerance requiring atazanavir cessation occurred in five pregnancies. Self-limiting, new-onset transaminitis was most common in first-line use, occurring in 11.0%. Atazanavir was commenced in five switch pregnancies in the presence of transaminitis, two of which discontinued atazanavir with persistent transaminitis. HIV-VL < 50 copies/mL was achieved in 89.3% preconception, 56.5% first-line, and 72.0% switch exposures. Singleton preterm delivery (<37 weeks) occurred in 11.7% preconception, 9.1% first-line, and 7.7% switch exposures. Four infants required phototherapy. There was one mother-to-child transmission in a poorly adherent woman.
CONCLUSIONS: These data suggest that atazanavir is well tolerated and can be safely prescribed as a component of combination antiretroviral therapy in pregnancy
Autopsy in adults with congenital heart disease (ACHD).
The adult congenital heart diseases (ACHD) population is exceeding the pediatric congenital heart diseases (CHD) population and is progressively expanding each year, representing more than 90% of patients with CHD. Of these, about 75% have undergone surgical and/or percutaneous intervention for palliation or correction. Autopsy can be a very challenging procedure in ACHD patients. The approach and protocol to be used may vary depending on whether the pathologists are facing native disease without surgical or percutaneous interventions, but with various degrees of cardiac remodeling, or previously palliated or corrected CHD. Moreover, interventions for the same condition have evolved over the last decades, as has perioperative myocardial preservations and postoperative care, with different long-term sequelae depending on the era in which patients were operated on. Careful clinicopathological correlation is, thus, required to assist the pathologist in performing the autopsy and reaching a diagnosis regarding the cause of death. Due to the heterogeneity of the structural abnormalities, and the wide variety of surgical and interventional procedures, there are no standard methods for dissecting the heart at autopsy. In this paper, we describe the most common types of CHDs that a pathologist could encounter at autopsy, including the various types of surgical and percutaneous procedures and major pathological manifestations. We also propose a practical systematic approach to the autopsy of ACHD patients
Higgs Physics: Theory
I review the theoretical aspects of the physics of Higgs bosons, focusing on
the elements that are relevant for the production and detection at present
hadron colliders. After briefly summarizing the basics of electroweak symmetry
breaking in the Standard Model, I discuss Higgs production at the LHC and at
the Tevatron, with some focus on the main production mechanism, the gluon-gluon
fusion process, and summarize the main Higgs decay modes and the experimental
detection channels. I then briefly survey the case of the minimal
supersymmetric extension of the Standard Model. In a last section, I review the
prospects for determining the fundamental properties of the Higgs particles
once they have been experimentally observed.Comment: 21 pages, 15 figures. Talk given at the XXV International Symposium
on Lepton Photon Interactions at High Energies (Lepton Photon 11), 22-27
August 2011, Mumbai, Indi
Higgs production in CP-violating supersymmetric cascade decays: probing the `open hole' at the Large Hadron Collider
A benchmark CP-violating supersymmetric scenario (known as 'CPX-scenario' in
the literature) is studied in the context of the Large Hadron Collider (LHC).
It is shown that the LHC, with low to moderate accumulated luminosity, will be
able to probe the existing `hole' in the - plane, which
cannot be ruled out by the LEP data. We explore the parameter space with
cascade decay of third generation squarks and gluino with CP-violating decay
branching fractions. We propose a multi-channel analysis to probe this
parameter space some of which are background free at an integrated luminosity
of 5-10 fb. Specially, multi-lepton final states (3\l,\, 4\l and like
sign di-lepton) are almost background free and have reach for the
corresponding signals with very early data of LHC for both 14 TeV and 7 TeV
center of mass energy.Comment: 24 pages, 9 figures, references added as in the journal versio
A Schwarz lemma for K\"ahler affine metrics and the canonical potential of a proper convex cone
This is an account of some aspects of the geometry of K\"ahler affine metrics
based on considering them as smooth metric measure spaces and applying the
comparison geometry of Bakry-Emery Ricci tensors. Such techniques yield a
version for K\"ahler affine metrics of Yau's Schwarz lemma for volume forms. By
a theorem of Cheng and Yau there is a canonical K\"ahler affine Einstein metric
on a proper convex domain, and the Schwarz lemma gives a direct proof of its
uniqueness up to homothety. The potential for this metric is a function
canonically associated to the cone, characterized by the property that its
level sets are hyperbolic affine spheres foliating the cone. It is shown that
for an -dimensional cone a rescaling of the canonical potential is an
-normal barrier function in the sense of interior point methods for conic
programming. It is explained also how to construct from the canonical potential
Monge-Amp\`ere metrics of both Riemannian and Lorentzian signatures, and a mean
curvature zero conical Lagrangian submanifold of the flat para-K\"ahler space.Comment: Minor corrections. References adde
- …