775 research outputs found
Symmetry breaking boundary conditions and WZW orbifolds
Symmetry breaking boundary conditions for WZW theories are discussed. We
derive explicit formulae for the reflection coefficients in the presence of
boundary conditions that preserve only an orbifold subalgebra with respect to
an involutive automorphism of the chiral algebra. The characters and modular
transformations of the corresponding orbifold theories are computed. Both inner
and outer automorphisms are treated.Comment: 39 pages, LaTeX2
Boundary conformal fields and Tomita--Takesaki theory
Motivated by formal similarities between the continuum limit of the Ising
model and the Unruh effect, this paper connects the notion of an Ishibashi
state in boundary conformal field theory with the Tomita--Takesaki theory for
operator algebras. A geometrical approach to the definition of Ishibashi states
is presented, and it is shownthat, when normalisable the Ishibashi states are
cyclic separating states, justifying the operator state correspondence. When
the states are not normalisable Tomita--Takesaki theory offers an alternative
approach based on left Hilbert algebras, opening the way to extensions of our
construction and the state-operator correspondence.Comment: plain Te
Hepatitis B and C Viruses and Hepatocellular Carcinoma
Chronic liver disease is responsible for over 1.4 million deaths annually  [1] and is characterized by permanent inflammatory processes that predispose to liver cancer and in particular hepatocellular carcinoma (HCC). In healthy liver, inflammatory processes stimulate growth and repair and restore normal liver architecture. However, if liver inflammation becomes chronic, the balance of damage versus regeneration in the liver is disrupted and can lead to the formation of excessive scar tissue, termed fibrosis. In the long-term, an exacerbation of fibrosis will lead to cirrhosis, which is characterized by abnormal liver architecture and function and is associated with a significant reduction in overall health and wellbeing. At cirrhotic stages, liver damage is often irreversible or difficult to treat. Cirrhosis leads frequently to death from liver failure or to HCC (Figure 1). Indeed, HCC is the first cause of death in cirrhotic patients [2], and is a tumor with poor prognosis, ranking third in terms of death by cancer. Furthermore, it is the fifth most prevalent cancer worldwide, with 800,000 new cases per year in the world [2,3]. [...
A finite-volume scheme for modeling compressible magnetohydrodynamic flows at low Mach numbers in stellar interiors
Fully compressible magnetohydrodynamic (MHD) simulations are a fundamental
tool for investigating the role of dynamo amplification in the generation of
magnetic fields in deep convective layers of stars. The flows that arise in
such environments are characterized by low (sonic) Mach numbers (M_son < 0.01
). In these regimes, conventional MHD codes typically show excessive
dissipation and tend to be inefficient as the Courant-Friedrichs-Lewy (CFL)
constraint on the time step becomes too strict. In this work we present a new
method for efficiently simulating MHD flows at low Mach numbers in a
space-dependent gravitational potential while still retaining all effects of
compressibility. The proposed scheme is implemented in the finite-volume
Seven-League Hydro (SLH) code, and it makes use of a low-Mach version of the
five-wave Harten-Lax-van Leer discontinuities (HLLD) solver to reduce numerical
dissipation, an implicit-explicit time discretization technique based on Strang
splitting to overcome the overly strict CFL constraint, and a well-balancing
method that dramatically reduces the magnitude of spatial discretization errors
in strongly stratified setups. The solenoidal constraint on the magnetic field
is enforced by using a constrained transport method on a staggered grid. We
carry out five verification tests, including the simulation of a small-scale
dynamo in a star-like environment at M_son ~ 0.001 . We demonstrate that the
proposed scheme can be used to accurately simulate compressible MHD flows in
regimes of low Mach numbers and strongly stratified setups even with moderately
coarse grids
The GEMAS Project: Geochemistry of European agricultural and grazing land soils.
Viene illustrato il progetto GEMAS che ha interessato la campionatura e le analisi di suoli dell'ntero continente Europeo da parte dei Servizi Geologici d'Europa, nell'ĂŹambito delle attivitĂ dell'EuroGeoSurvey
Twisted brane charges for non-simply connected groups
The charges of the twisted branes for strings on the group manifold SU(n)/Z_d
are determined. To this end we derive explicit (and remarkably simple) formulae
for the relevant NIM-rep coefficients. The charge groups of the twisted and
untwisted branes are compared and found to agree for the cases we consider.Comment: 30 page
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