56 research outputs found
Irrational Conformal Field Theory
This is a review of irrational conformal field theory, which includes
rational conformal field theory as a small subspace. Central topics of the
review include the Virasoro master equation, its solutions and the dynamics of
irrational conformal field theory. Discussion of the dynamics includes the
generalized Knizhnik-Zamolodchikov equations on the sphere, the corresponding
heat-like systems on the torus and the generic world- sheet action of
irrational conformal field theory.Comment: 195 pages, Latex, 12 figures, to appear in Physics Reports. Typos
corrected in Sections 13 and 14, and a footnote added in Section 1
Plane Gravitational Waves in String Theory
We analyze the coset model (E_2^c \ti E_2^c)/E_2^c and construct a class of
exact string vacua which describe plane gravitational waves and their duals,
generalizing the plane wave background found by Nappi and Witten. In
particular, the vector gauging describes a two-parameter family of singular
geometries with two isometries, which is dual to plane gravitational waves. In
addition, there is a mixed vector-axial gauging which describes a one-parameter
family of plane waves with five isometries. These two backgrounds are related
by a duality transformation which generalizes the known axial-vector duality
for abelian subgroups.Comment: 27 pages, Latex, CPTH-A299.049
Structural Aspects of Two-Dimensional Anomalous Gauge Theories
A foundational investigation of the basic structural properties of
two-dimensional anomalous gauge theories is performed. The Hilbert space is
constructed as the representation of the intrinsic local field algebra
generated by the fundamental set of field operators whose Wightman functions
define the model. We examine the effect of the use of a redundant field algebra
in deriving basic properties of the models and show that different results may
arise, as regards the physical properties of the generalized chiral model, in
restricting or not the Hilbert space as representation of the intrinsic local
field algebra. The question referring to considering the vector Schwinger model
as a limit of the generalized anomalous model is also discussed. We show that
this limit can only be consistently defined for a field subalgebra of the
generalized model.Comment: 40 pages. Latex, to appear in Annals of Physic
Instantons on Quivers and Orientifolds
We compute the prepotential for gauge theories descending from
SYM via quiver projections and mass deformations.
This accounts for gauge theories with product gauge groups and bifundamental
matter. The case of massive orientifold gauge theories with gauge group SO/Sp
is also described. In the case with no gravitational corrections the results
are shown to be in agreement with Seiberg-Witten analysis and previous results
in the literature.Comment: 28 pages, revised version, references added, some typos correcte
Scalar Field Dark Matter
This work is a review of the last results of research on the Scalar Field
Dark Matter model of the Universe at cosmological and at galactic level. We
present the complete solution to the scalar field cosmological scenario in
which the dark matter is modeled by a scalar field with the scalar
potential and the
dark energy is modeled by a scalar field , endowed with the scalar
potential , which together compose the 95% of the total
matter energy in the Universe. The model presents successfully deals with the
up to date cosmological observations, and is a good candidate to treat the dark
matter problem at the galactic level.Comment: 11 pagez, 5 figures, REVTeX. To appear in proceedings of the
``Mexican Meeting on Exact Solutions and Scalar Fields in Gravity '', in
honour of Heinz Dehnen's 65th Birthday and Dietrich Kramer's 60th Birthday.
Mexico D.F., Mexico, in press. More info at
http://www.fis.cinvestav.mx/~siddh/PHI
Analytic Methods in Nonperturbative QCD
Recently developed analytic methods in the framework of the Field Correlator
Method are reviewed in this series of four lectures and results of calculations
are compared to lattice data and experiment. Recent lattice data demonstrating
the Casimir scaling of static quark interaction strongly support the FCM and
leave very little space for all other theoretical models, e.g. instanton
gas/liquid model. Results of calculations for mesons, baryons, quark-gluon
plasma and phase transition temperature demonstrate that new analytic methods
are a powerful tool of nonperturbative QCD along with lattice simulations.Comment: LaTeX, 34 pages; Lectures given at the 13th Indian-Summer School
"Understanding the Structure of Hadrons", August 28 - September 1, 2000,
Prague, Czech Republi
Possible origins of macroscopic left-right asymmetry in organisms
I consider the microscopic mechanisms by which a particular left-right (L/R)
asymmetry is generated at the organism level from the microscopic handedness of
cytoskeletal molecules. In light of a fundamental symmetry principle, the
typical pattern-formation mechanisms of diffusion plus regulation cannot
implement the "right-hand rule"; at the microscopic level, the cell's
cytoskeleton of chiral filaments seems always to be involved, usually in
collective states driven by polymerization forces or molecular motors. It seems
particularly easy for handedness to emerge in a shear or rotation in the
background of an effectively two-dimensional system, such as the cell membrane
or a layer of cells, as this requires no pre-existing axis apart from the layer
normal. I detail a scenario involving actin/myosin layers in snails and in C.
elegans, and also one about the microtubule layer in plant cells. I also survey
the other examples that I am aware of, such as the emergence of handedness such
as the emergence of handedness in neurons, in eukaryote cell motility, and in
non-flagellated bacteria.Comment: 42 pages, 6 figures, resubmitted to J. Stat. Phys. special issue.
Major rewrite, rearranged sections/subsections, new Fig 3 + 6, new physics in
Sec 2.4 and 3.4.1, added Sec 5 and subsections of Sec
Vibrio parahaemolyticus, enterotoxigenic Escherichia coli, enterohemorrhagic Escherichia coli and Vibrio cholerae
This review highlighted the following: (i) pathogenic mechanism of the thermostable direct hemolysin produced by Vibrio parahaemolyticus, especially on its cardiotoxicity, (ii) heat-labile and heat-stable enterotoxins produced by enterotoxigenic Escherichia coli, especially structure–activity relationship of heat-stable enterotoxin, (iii) RNA N-glycosidase activity of Vero toxins (VT1 and VT2) produced by enterohemorrhagic Escherichia coli O157:H7, (iv) discovery of Vibrio cholerae O139, (v) isolation of new variant of Vibrio cholerae O1 El Tor that carries classical ctxB, and production of high concentration of cholera toxin by these strains, and (vi) conversion of viable but nonculturable (VBNC) Vibrio cholerae to culturable state by co-culture with eukaryotic cells
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