105 research outputs found
ABJM Baryon Stability and Myers effect
We consider magnetically charged baryon vertex like configurations in AdS^4 X
CP^3 with a reduced number of quarks l. We show that these configurations are
solutions to the classical equations of motion and are stable beyond a critical
value of l. Given that the magnetic flux dissolves D0-brane charge it is
possible to give a microscopical description in terms of D0-branes expanding
into fuzzy CP^n spaces by Myers dielectric effect. Using this description we
are able to explore the region of finite 't Hooft coupling.Comment: 29 pages, Latex; minor changes; version to appear in JHE
Charged particle-like branes in ABJM
We study the effect of adding lower dimensional brane charges to the 't Hooft
monopole, di-baryon and baryon vertex configurations in . We show that these configurations capture the background fluxes
in a way that depends on the induced charges, and therefore, require additional
fundamental strings in order to cancel the worldvolume tadpoles. The study of
the dynamics reveals that the charges must lie inside some interval in order to
find well defined configurations, a situation familiar from the baryon vertex
in with charges. For the baryon vertex and the di-baryon the
number of fundamental strings must also lie inside an allowed interval. Our
configurations are sensitive to the flat -field recently suggested in the
literature. We make some comments on its possible role. We also discuss how
these configurations are modified in the presence of a non-zero Romans mass.Comment: 31 pages, 14 figures, discussion of charges improved, published
versio
Non-singlet Baryons in Less Supersymmetric Backgrounds
We analyze the holographic description of non-singlet baryons in various
backgrounds with reduced supersymmetries and/or confinement. We show that they
exist in all AdS_5xY_5 backgrounds with Y_5 an Einstein manifold bearing five
form flux, for a number of quarks 5N/8< k< N, independently on the
supersymmetries preserved. This result still holds for gamma_i deformations. In
the confining Maldacena-Nunez background non-singlet baryons also exist,
although in this case the interval for the number of quarks is reduced as
compared to the conformal case. We generalize these configurations to include a
non-vanishing magnetic flux such that a complementary microscopical description
can be given in terms of lower dimensional branes expanding into fuzzy baryons.
This description is a first step towards exploring the finite 't Hooft coupling
region.Comment: 36 Pages, 1 figure, Latex, v2: few minor changes, JHEP versio
A Vector Non-abelian Chern-Simons Duality
Abelian Chern-Simons gauge theory is known to possess a `-self-dual'
action where its coupling constant is inverted {\it i.e.} . Here a vector non-abelian duality is found in the
pure non-abelian Chern-Simons action at the classical level. The dimensional
reduction of the dual Chern-Simons action to two-dimensions constitutes a dual
Wess-Zumino-Witten action already given in the literature.Comment: 14+1 pages, LaTeX file, no figures, version to appear in Phys. Rev
On S-duality in (2+1)-Chern-Simons Supergravity
Strong/weak coupling duality in Chern-Simons supergravity is studied. It is
argued that this duality can be regarded as an example of superduality. The use
of supergroup techniques for the description of Chern-Simons supergravity
greatly facilitates the analysis.Comment: 10+1 pages, latex, no figure
Lectures on localization and matrix models in supersymmetric Chern-Simons-matter theories
In these lectures I give a pedagogical presentation of some of the recent
progress in supersymmetric Chern-Simons-matter theories, coming from the use of
localization and matrix model techniques. The goal is to provide a simple
derivation of the exact interpolating function for the free energy of ABJM
theory on the three-sphere, which implies in particular the N^{3/2} behavior at
strong coupling. I explain in detail part of the background needed to
understand this derivation, like holographic renormalization, localization of
path integrals, and large N techniques in matrix modelsComment: 73 pages, 7 figures. v2: references and clarifications added,
misprints corrected. v3: more references, clarifications, and corrections.
v4: more corrections and clarifications, final version to appear in J. Phys.
Implications of the polymorphism of HLA-G on its function, regulation, evolution and disease association
The HLA-G gene displays several peculiarities that are distinct from those of classical HLA class I genes. The unique structure of the HLA-G molecule permits a restricted peptide presentation and allows the modulation of the cells of the immune system. Although polymorphic sites may potentially influence all biological functions of HLA-G, those present at the promoter and 3′ untranslated regions have been particularly studied in experimental and pathological conditions. The relatively low polymorphism observed in the MHC-G coding region both in humans and apes may represent a strong selective pressure for invariance, whereas, in regulatory regions several lines of evidence support the role of balancing selection. Since HLA-G has immunomodulatory properties, the understanding of gene regulation and the role of polymorphic sites on gene function may permit an individualized approach for the future use of HLA-G for therapeutic purposes
Search for Spatial Correlations of Neutrinos with Ultra-high-energy Cosmic Rays
For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data are provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above ∼50 EeV are provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino sample optimized for point-source searches to search for excesses of neutrino clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses have found a significant excess, and previously reported overfluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs
A Field Guide to Pandemic, Epidemic and Sporadic Clones of Methicillin-Resistant Staphylococcus aureus
In recent years, methicillin-resistant Staphylococcus aureus
(MRSA) have become a truly global challenge. In addition to the long-known
healthcare-associated clones, novel strains have also emerged outside of the
hospital settings, in the community as well as in livestock. The emergence and
spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an
additional cause for concern. In order to provide an overview of pandemic,
epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates
of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu
Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference
strains from the United States have been genotyped by DNA microarray analysis.
This technique allowed the assignment of the MRSA isolates to 34 distinct
lineages which can be clearly defined based on non-mobile genes. The results
were in accordance with data from multilocus sequence typing. More than 100
different strains were distinguished based on affiliation to these lineages,
SCCmec type and the presence or absence of PVL. These
strains are described here mainly with regard to clinically relevant
antimicrobial resistance- and virulence-associated markers, but also in relation
to epidemiology and geographic distribution. The findings of the study show a
high level of biodiversity among MRSA, especially among strains harbouring
SCCmec IV and V elements. The data also indicate a high
rate of genetic recombination in MRSA involving SCC elements, bacteriophages or
other mobile genetic elements and large-scale chromosomal replacements
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