239 research outputs found
Deconstructing holographic liquids
We argue that there exist simple effective field theories describing the
long-distance dynamics of holographic liquids. The degrees of freedom
responsible for the transport of charge and energy-momentum are Goldstone
modes. These modes are coupled to a strongly coupled infrared sector through
emergent gauge and gravitational fields. The IR degrees of freedom are
described holographically by the near-horizon part of the metric, while the
Goldstone bosons are described by a field-theoretical Lagrangian. In the cases
where the holographic dual involves a black hole, this picture allows for a
direct connection between the holographic prescription where currents live on
the boundary, and the membrane paradigm where currents live on the horizon. The
zero-temperature sound mode in the D3-D7 system is also re-analyzed and
re-interpreted within this formalism.Comment: 21 pages, 2 figure
A conical deficit in the AdS4/CFT3 correspondence
Inspired by the AdS/CFT correspondence we propose a new duality that allow
the study of strongly coupled field theories living in a 2+1 conical
space-time. Solving the 4-d Einstein equations in the presence of an infinite
static string and negative cosmological constant we obtain a conical AdS4
space-time whose boundary is identified with the 2+1 cone found by Deser,
Jackiw and 't Hooft. Using the AdS4/CFT3 correspondence we calculate retarded
Green's functions of scalar operators living in the cone.Comment: v3, 14 pages. We reinterpret our results for the Green's functions in
the con
Strange metals and the AdS/CFT correspondence
I begin with a review of quantum impurity models in condensed matter physics,
in which a localized spin degree of freedom is coupled to an interacting
conformal field theory in d = 2 spatial dimensions. Their properties are
similar to those of supersymmetric generalizations which can be solved by the
AdS/CFT correspondence; the low energy limit of the latter models is described
by a AdS2 geometry. Then I turn to Kondo lattice models, which can be described
by a mean- field theory obtained by a mapping to a quantum impurity coupled to
a self-consistent environment. Such a theory yields a 'fractionalized Fermi
liquid' phase of conduction electrons coupled to a critical spin liquid state,
and is an attractive mean-field theory of strange metals. The recent
holographic description of strange metals with a AdS2 x R2 geometry is argued
to be related to such mean-field solutions of Kondo lattice models.Comment: 19 pages, 4 figures; Plenary talk at Statphys24, Cairns, Australia,
July 2010; (v2) added refs; (v3) more ref
Counting Chiral Operators in Quiver Gauge Theories
We discuss in detail the problem of counting BPS gauge invariant operators in
the chiral ring of quiver gauge theories living on D-branes probing generic
toric CY singularities. The computation of generating functions that include
counting of baryonic operators is based on a relation between the baryonic
charges in field theory and the Kaehler moduli of the CY singularities. A study
of the interplay between gauge theory and geometry shows that given geometrical
sectors appear more than once in the field theory, leading to a notion of
"multiplicities". We explain in detail how to decompose the generating function
for one D-brane into different sectors and how to compute their relevant
multiplicities by introducing geometric and anomalous baryonic charges. The
Plethystic Exponential remains a major tool for passing from one D-brane to
arbitrary number of D-branes. Explicit formulae are given for few examples,
including C^3/Z_3, F_0, and dP_1.Comment: 75 pages, 22 figure
Evidence of a landlocked reproducing population of the marine pejerrey Odontesthes argentinensis (Actinopterygii; Atherinopsidae)
In South America, the order Atheriniformes includes the monophyletic genus Odontesthes with 20 species that inhabit freshwater, estuarine and coastal environments. Pejerrey Odontesthes argentinensis is widely distributed in coastal and estuarine areas of the Atlantic Ocean and is known to foray into estuaries of river systems, particularly in conditions of elevated salinity. However, to our knowledge, a landlocked selfâsustaining population has never been recorded. In this study, we examined the pejerrey population of Salada de Pedro Luro Lake (southâeast of Buenos Aires Province, Argentina) to clarify its taxonomic identity. An integrative taxonomic analysis based on traditional meristic, landmarkâbased morphometrics and genetic techniques suggests that the Salada de Pedro Luro pejerrey population represents a novel case of physiological and morphological adaptation of a marine pejerrey species to a landlocked environment and emphasises the environmental plasticity of this group of fishesFil: Colautti, Dario CĂ©sar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de LimnologĂa "Dr. RaĂșl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de LimnologĂa; ArgentinaFil: Miranda, Leandro Andres. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BiotecnolĂłgicas. Instituto de Investigaciones BiotecnolĂłgicas "Dr. RaĂșl AlfonsĂn" (sede ChascomĂșs). Universidad Nacional de San MartĂn. Instituto de Investigaciones BiotecnolĂłgicas. Instituto de Investigaciones BiotecnolĂłgicas "Dr. RaĂșl AlfonsĂn" (sede ChascomĂșs); ArgentinaFil: GonzĂĄlez Castro, M.. Universidad Nacional de Mar del Plata; ArgentinaFil: Villanova, Vanina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: StrĂŒssmann, Carlos A.. Tokyo University Of Marine Science And Technology; JapĂłnFil: Mancini, Miguel Alberto. Universidad Nacional de RĂo Cuarto; ArgentinaFil: Maiztegui, TomĂĄs. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de LimnologĂa "Dr. RaĂșl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de LimnologĂa; ArgentinaFil: Berasain, Gustavo. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios; ArgentinaFil: Hattori, Ricardo Shohei. Tokyo University of Marine Science and Technology; JapĂłnFil: Grosman, Manuel FabiĂĄn. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Sanzano, Pablo Miguel. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Lozano, I.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Llamazares Vegh, Sabina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Salinas, V.. Universidad Nacional de RĂo Cuarto; ArgentinaFil: Del Ponti, O.. Universidad Nacional de La Pampa; ArgentinaFil: Fresno, P.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BiotecnolĂłgicas. Instituto de Investigaciones BiotecnolĂłgicas "Dr. RaĂșl AlfonsĂn" (sede ChascomĂșs). Universidad Nacional de San MartĂn. Instituto de Investigaciones BiotecnolĂłgicas. Instituto de Investigaciones BiotecnolĂłgicas "Dr. RaĂșl AlfonsĂn" (sede ChascomĂșs); ArgentinaFil: Minotti, Priscilla Gail. Universidad Nacional de San MartĂn; ArgentinaFil: Yamamoto, Y.. Tokyo University Of Marine Science And Technology; JapĂłnFil: BaigĂșn, C.. Universidad Nacional de San MartĂn; Argentin
Mesonic Chiral Rings in Calabi-Yau Cones from Field Theory
We study the half-BPS mesonic chiral ring of the N=1 superconformal quiver
theories arising from N D3-branes stacked at Y^pq and L^abc Calabi-Yau conical
singularities. We map each gauge invariant operator represented on the quiver
as an irreducible loop adjoint at some node, to an invariant monomial, modulo
relations, in the gauged linear sigma model describing the corresponding bulk
geometry. This map enables us to write a partition function at finite N over
mesonic half-BPS states. It agrees with the bulk gravity interpretation of
chiral ring states as cohomologically trivial giant gravitons. The quiver
theories for L^aba, which have singular base geometries, contain extra
operators not counted by the naive bulk partition function. These extra
operators have a natural interpretation in terms of twisted states localized at
the orbifold-like singularities in the bulk.Comment: Latex, 25pgs, 12 figs, v2: minor clarification
AAV-mediated delivery of an anti-BACE1 VHH alleviates pathology in an Alzheimer's disease model
Single domain antibodies (VHHs) are potentially disruptive therapeutics, with important biological value for treatment of several diseases, including neurological disorders. However, VHHs have not been widely used in the central nervous system (CNS), largely because of their restricted bloodâbrain barrier (BBB) penetration. Here, we propose a gene transfer strategy based on BBB-crossing adeno-associated virus (AAV)-based vectors to deliver VHH directly into the CNS. As a proof-of-concept, we explored the potential of AAV-delivered VHH to inhibit BACE1, a well-characterized target in Alzheimerâs disease. First, we generated a panel of VHHs targeting BACE1, one of which, VHH-B9, shows high selectivity for BACE1 and efficacy in lowering BACE1 activity in vitro. We further demonstrate that a single systemic dose of AAV-VHH-B9 produces positive long-term (12âmonths plus) effects on amyloid load, neuroinflammation, synaptic function, and cognitive performance, in the AppNL-G-F Alzheimerâs mouse model. These results constitute a novel therapeutic approach for neurodegenerative diseases, which is applicable to a range of CNS disease targets
M2-Branes and Fano 3-folds
A class of supersymmetric gauge theories arising from M2-branes probing
Calabi-Yau 4-folds which are cones over smooth toric Fano 3-folds is
investigated. For each model, the toric data of the mesonic moduli space is
derived using the forward algorithm. The generators of the mesonic moduli space
are determined using Hilbert series. The spectrum of scaling dimensions for
chiral operators is computed.Comment: 128 pages, 39 figures, 42 table
A competitive scheme for storing sparse representation of X-Ray medical images
A competitive scheme for economic storage of the informational content of an X-Ray image, as it can be used for further processing, is presented. It is demonstrated that sparse representation of that type of data can be encapsulated in a small file without affecting the quality of the recovered image. The proposed representation, which is inscribed within the context of data reduction, provides a format for saving the image information in a way that could assist methodologies for analysis and classification. The competitiveness of the resulting file is compared against the compression standards JPEG and JPEG200
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