3,638 research outputs found
On the Special Significance of the Latest PAMELA Results in Astroparticle Physics
In continuation of their earlier measurements, the PAMELA group reported data
on antiproton flux and ratios in 2010 at much higher energies. In
past we had dealt with these specific aspects of PAMELA data in great detail
and each time we captured the contemporary data-trends quite successfully with
the help of a multiple production model of secondary antiprotons with some
non-standard ilk and with some other absolutely standard assumptions and
approximations. In this work we aim at presenting a comprehensive and valid
description of all the available data on antiproton flux and the nature of
ratios at the highest energies reported so far by the PAMELA
experiment in 2010. The main physical implication of all this would, in the
end, be highlighted.Comment: 8 pages, 6 figure
Thermodynamics of Plasmaballs and Plasmarings in 3+1 Dimensions
We study localized plasma configurations in 3+1 dimensional massive field
theories obtained by Scherk-Schwarz compactification of 4+1 dimensional CFT to
predict the thermodynamic properties of localized blackholes and blackrings in
Scherk-Schwarz compactified using the AdS/CFT correspondence. We
present an exact solution to the relativistic Navier-Stokes equation in the
thin ring limit of the fluid configuration. We also perform a thorough
numerical analysis to obtain the thermodynamic properties of the most general
solution. Finally we compare our results with the recent proposal for the phase
diagram of blackholes in six flat dimensions and find some similarities but
other differences.Comment: 18 pages, 11 figures, latex; v2: Typos corrected and new references
adde
Classical no-cloning theorem under Liouville dynamics by non-Csisz\'ar f-divergence
The Csisz\'ar f-divergence, which is a class of information distances, is
known to offer a useful tool for analysing the classical counterpart of the
cloning operations that are quantum mechanically impossible for the factorized
and marginality classical probability distributions under Liouville dynamics.
We show that a class of information distances that does not belong to this
divergence class also allows for the formulation of a classical analogue of the
quantum no-cloning theorem. We address a family of nonlinear Liouville-like
equations, and generic distances, to obtain constraints on the corresponding
functional forms, associated with the formulation of classical analogue of the
no-cloning principle.Comment: 6 pages, revised, published versio
Non-extensivity of the QCD pT spectra
We try to establish a connection between the hadronic distributions, in
proton-proton collisions at very high transverse momentum ,
obtained via perturbative QCD and the Tsallis non extensive statistics. Our
motivation is that while the former is expected to be valid at extremely high
momentum, due to asymptotic freedom, the latter has been very successful in
describing experimental spectra over a wide range of momentum. Matching the non
extensive statistics with the asymptotic behaviour expected
from QCD leads to the value of .Comment: 4 page
String Network and U-Duality
We discuss the generalization of recently discovered BPS configurations,
corresponding to the planar string networks, to non-planar ones by considering
the U-duality symmetry of type II string theory in various dimensions. As an
explicit example, we analyze the string solutions in 8-dimensional space-time,
carrying SL(3) charges, and show that by aligning the strings along various
directions appropriately, one can obtain a string network which preserves 1/8
supersymmetry.Comment: 8 pages, latex, references added, minor modification
Neutrino Bremsstrahlung Process in highly degenerate magnetized electron gas
In this article the neutrino bremsstrahlung process is considered in presence
of strong magnetic field, though the calculations for this process in absence
of magnetic field are also carried out simultaneously. The electrons involved
in this process are supposed to be highly degenerate and relativistic. The
scattering cross sections and energy loss rates for both cases, in presence and
absence of magnetic field, are calculated in the extreme-relativistic limit.
Two results are compared in the range of temperature K K and magnetic field G at a fixed density
, a typical environment during the cooling of magnetized
neutron star. The interpretation of our result is briefly discussed and the
importance of this process during the stellar evolution is speculated.Comment: 12 pages including 2 figures and 1 tabl
Distances between quantum states in the tomographic-probability representation
Distances between quantum states are reviewed within the framework of the
tomographic-probability representation. Tomographic approach is based on
observed probabilities and is straightforward for data processing. Different
states are distinguished by comparing corresponding probability-distribution
functions. Fidelity as well as other distance measures are expressed in terms
of tomograms.Comment: 10 pages, Contribution to the 16th Central European Workshop on
Quantum Optics (CEWQO'09), May 23-27, 2009, Turku, Finlan
Fluid dynamics of R-charged black holes
We construct electrically charged AdS_5 black hole solutions whose charge,
mass and boost-parameters vary slowly with the space-time coordinates. From the
perspective of the dual theory, these are equivalent to hydrodynamic
configurations with varying chemical potential, temperature and velocity
fields. We compute the boundary theory transport coefficients associated with a
derivative expansion of the energy momentum tensor and R-charge current up to
second order. In particular, we find a first order transport coefficient
associated with the axial component of the current.Comment: 31 pages, v2: published version; added some references, discussion of
the charge-current changed, results unchanged, v3: typo in formula (15)
changed, v4: added footnote 3 in order to clarify the relation of our results
to those of arXiv:0809.259
Weak Field Black Hole Formation in Asymptotically AdS Spacetimes
We use the AdS/CFT correspondence to study the thermalization of a strongly
coupled conformal field theory that is forced out of its vacuum by a source
that couples to a marginal operator. The source is taken to be of small
amplitude and finite duration, but is otherwise an arbitrary function of time.
When the field theory lives on , the source sets up a
translationally invariant wave in the dual gravitational description. This wave
propagates radially inwards in space and collapses to form a black
brane. Outside its horizon the bulk spacetime for this collapse process may
systematically be constructed in an expansion in the amplitude of the source
function, and takes the Vaidya form at leading order in the source amplitude.
This solution is dual to a remarkably rapid and intriguingly scale dependent
thermalization process in the field theory. When the field theory lives on a
sphere the resultant wave either slowly scatters into a thermal gas (dual to a
glueball type phase in the boundary theory) or rapidly collapses into a black
hole (dual to a plasma type phase in the field theory) depending on the time
scale and amplitude of the source function. The transition between these two
behaviors is sharp and can be tuned to the Choptuik scaling solution in
.Comment: 50 pages + appendices, 6 figures, v2: Minor revisions, references
adde
Multiple mitochondrial introgression events and heteroplasmy in trypanosoma cruzi revealed by Maxicircle MLST and next generation sequencing
Background
Mitochondrial DNA is a valuable taxonomic marker due to its relatively fast rate of evolution. In Trypanosoma cruzi, the causative agent of Chagas disease, the mitochondrial genome has a unique structural organization consisting of 20–50 maxicircles (∼20 kb) and thousands of minicircles (0.5–10 kb). T. cruzi is an early diverging protist displaying remarkable genetic heterogeneity and is recognized as a complex of six discrete typing units (DTUs). The majority of infected humans are asymptomatic for life while 30–35% develop potentially fatal cardiac and/or digestive syndromes. However, the relationship between specific clinical outcomes and T. cruzi genotype remains elusive. The availability of whole genome sequences has driven advances in high resolution genotyping techniques and re-invigorated interest in exploring the diversity present within the various DTUs.
Methodology/Principal Findings
To describe intra-DTU diversity, we developed a highly resolutive maxicircle multilocus sequence typing (mtMLST) scheme based on ten gene fragments. A panel of 32 TcI isolates was genotyped using the mtMLST scheme, GPI, mini-exon and 25 microsatellite loci. Comparison of nuclear and mitochondrial data revealed clearly incongruent phylogenetic histories among different geographical populations as well as major DTUs. In parallel, we exploited read depth data, generated by Illumina sequencing of the maxicircle genome from the TcI reference strain Sylvio X10/1, to provide the first evidence of mitochondrial heteroplasmy (heterogeneous mitochondrial genomes in an individual cell) in T. cruzi.
Conclusions/Significance
mtMLST provides a powerful approach to genotyping at the sub-DTU level. This strategy will facilitate attempts to resolve phenotypic variation in T. cruzi and to address epidemiologically important hypotheses in conjunction with intensive spatio-temporal sampling. The observations of both general and specific incidences of nuclear-mitochondrial phylogenetic incongruence indicate that genetic recombination is geographically widespread and continues to influence the natural population structure of TcI, a conclusion which challenges the traditional paradigm of clonality in T. cruzi
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