206 research outputs found

    Unitarity bounds and RG flows in time dependent quantum field theory

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    We generalize unitarity bounds on operator dimensions in conformal field theory to field theories with spacetime dependent couplings. Below the energy scale of spacetime variation of the couplings, their evolution can strongly affect the physics, effectively shifting the infrared operator scaling and unitarity bounds determined from correlation functions in the theory. We analyze this explicitly for large-NN double-trace flows, and connect these to UV complete field theories. One motivating class of examples comes from our previous work on FRW holography, where this effect explains the range of flavors allowed in the dual, time dependent, field theory.Comment: 38 page

    On Coordinate Transformations in Planar Noncommutative Theories

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    We consider planar noncommutative theories such that the coordinates verify a space-dependent commutation relation. We show that, in some special cases, new coordinates may be introduced that have a constant commutator, and as a consequence the construction of Field Theory models may be carried out by an application of the standard Moyal approach in terms of the new coordinates. We apply these ideas to the concrete example of a noncommutative plane with a curved interface. We also show how to extend this method to more general situations.Comment: 20 pages, 1 figure. references adde

    Application of Vertical Brackets in Orthodontial Treatments: A Laser Speckle Study

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    This paper reports the application of a laser speckle technique for orthodontial studies. The purpose of these studies is to certify the validity of a proposal related with a new type of apparatus, and the methodology to be used in orthodontial treatments. (P&aacute;rrafo extra&iacute;do a modo de resumen)</em

    Respuestas fisiológicas y moleculares al déficit hídrico en trigo (Triticum aestivum L.)

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    Physiological and molecular responses of five wheat genotypes: one Canadian cultivar, with low temperature tolerance, and 4 experimental lines, which demonstrated in the field high yield under drought stress were studied under water stress. We determined leaf relative water content and gene expression of rob 5 and dehydrins in response to low water availability. One genotype showed a higher RWC with less leaf Iresh weight and water soil content. There were not differences between genotypes in expression genes but, we found differences in gene expression between both tested genes. Rob 5 expressed in control as well as in stressed plants, while dehydrins only expressed in stressed plants and its expression increased as the water content of leaves decreased.Las respuestas fisiológicas y moleculares de cinco genotipos de trigo: un cultivar canadiense. tolerante a las bajas temperaturas y 4 líneas experimentales argentinas, que habían mostrado, un alto rendimiento a campo bajo condiciones de deficiencia hídrica, fueron estudiadas en condiciones de baja disponibilidad de agua. Se determine el contenido relativo de agua en las hojas y la expresión de 2 genes, rob 5 y dehidrinas, en respuesta a la baja disponibilidad de agua. Uno de los genotipos mostró mayor CRA con un menor contenido de agua en las hojas o en el suelo. No hubo diferencias genotípicas en la expresión de los genes sin embargo, fue diferente la expresión de estos, en respuesta al estr6s hídrico, dado que el gen Rob 5 se expresó tanto en las plantas control como en las estresadas, mientras que el de las dehydrinas solo se expresó en las plantas bajo estrés, y su expresión aumentó en función de la disminución del contenido relativo de agua de las hojas

    A microscopic theory of gauge mediation

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    We construct models of indirect gauge mediation where the dynamics responsible for breaking supersymmetry simultaneously generates a weakly coupled subsector of messengers. This provides a microscopic realization of messenger gauge mediation where the messenger and hidden sector fields are unified into a single sector. The UV theory is SQCD with massless and massive quarks plus singlets, and at low energies it flows to a weakly coupled quiver gauge theory. One node provides the primary source of supersymmetry breaking, which is then transmitted to the node giving rise to the messenger fields. These models break R-symmetry spontaneously, produce realistic gaugino and sfermion masses, and give a heavy gravitino.Comment: 24 pages, 2 figures, accepted to JHEP for publicatio

    Dynamic SU(2) Structure from Seven-branes

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    We obtain a family of supersymmetric solutions of type IIB supergravity with dynamic SU(2) structure, which describe the local geometry near a stack of four D7-branes and one O7-plane wrapping a rigid four-cycle. The deformation to a generalized complex geometry is interpreted as a consequence of nonperturbative effects in the seven-brane gauge theory. We formulate the problem for seven-branes wrapping the base of an appropriate del Pezzo cone, and in the near-stack limit in which the four-cycle is flat, we obtain an exact solution in closed form. Our solutions serve to characterize the local geometry of nonperturbatively-stabilized flux compactifications.Comment: 49 pages, 2 figures; v2: minor corrections, references adde

    Massive IIA flux compactifications and U-dualities

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    We attempt to find a rigorous formulation for the massive type IIA orientifold compactifications of string theory introduced in hep-th/0505160. An approximate double T-duality converts this background into IIA string theory on a twisted torus, but various arguments indicate that the back reaction of the orientifold on this geometry is large. In particular, an AdS calculation of the entropy suggests a scaling appropriate for N M2-branes, in a certain limit of the compactification, though not the one studied in hep-th/0505160. The M-theory lift of this specific regime is not 4 dimensional. We suggest that the generic limit of the background corresponds to a situation analogous to F-theory, where the string coupling is small in some regions of a compact geometry, and large in others, so that neither a long wavelength 11D SUGRA expansion, nor a world sheet expansion exists for these compactifications. We end with a speculation on the nature of the generic compactification.Comment: JHEP3 LaTeX - 34 pages - 3 figures; v2: Added references; v3: mistake in entropy scaling corrected, major changes in conclusions; v4: changed claims about original DeWolfe et al. setup, JHEP versio

    Using small molecules to facilitate exchange of bicarbonate and chloride anions across liposomal membranes

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    Bicarbonate is involved in a wide range of biological processes, which include respiration, regulation of intracellular pH and fertilization. In this study we use a combination of NMR spectroscopy and ion-selective electrode techniques to show that the natural product prodigiosin, a tripyrrolic molecule produced by microorganisms such as Streptomyces and Serratia, facilitates chloride/bicarbonate exchange (antiport) across liposomal membranes. Higher concentrations of simple synthetic molecules based on a 4,6-dihydroxyisophthalamide core are also shown to facilitate this antiport process. Although it is well known that proteins regulate Cl-/HCO3- exchange in cells, these results suggest that small molecules may also be able to regulate the concentration of these anions in biological systems

    Meta-Stable Dynamical Supersymmetry Breaking Near Points of Enhanced Symmetry

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    We show that metastable supersymmetry breaking is generic near certain enhanced symmetry points of gauge theory moduli spaces. Our model consists of two sectors coupled by a singlet and combines dynamical supersymmetry breaking with an O'Raifeartaigh mechanism in terms of confined variables. All relevant mass parameters, including the supersymmetry breaking scale, are generated dynamically. The metastable vacua appear as a result of a balance between non-perturbative and perturbative quantum effects along a pseudo-runaway direction.Comment: 27 pages, harvmac, 6 figure

    PHF13: A new player involved in RNA polymerase II transcriptional regulation and co-transcriptional splicing

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    We recently identified PHF13 as an H3K4me2/3 chromatin reader and transcriptional co-regulator. We found that PHF13 interacts with RNAPIIS5P and PRC2 stabilizing their association with active and bivalent promoters. Furthermore, mass spectrometry analysis identified ∼50 spliceosomal proteins in PHF13s interactome. Here, we will discuss the potential role of PHF13 in RNAPII pausing and co-transcriptional splicing
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