31,381 research outputs found
Spontaneous Symmetry Breaking in Tensor Theories
In this work we study spontaneous symmetry breaking patterns in tensor
models. We focus on the patterns which lead to effective matrix theories
transforming in the adjoint of . We find the explicit form of the
Goldstone bosons which are organized as matrix multiplets in the effective
theory. The choice of these symmetry breaking patterns is motivated by the fact
that, in some contexts, matrix theories are dual to gravity theories. Based on
this, we aim to build a bridge between tensor theories, quantum gravity and
holography.Comment: 40 pp, 1 fig. Update to match the published versio
The initial conditions of the Universe and holography
We address the initial conditions for an expanding cosmology using the
holographic principle. For the case of a closed model, the old prescription of
Fishler and Susskind, that uses the particle horizon to encode the bulk degrees
of freedom, can be implemented for accelerated models with enough acceleration.
As a bonus we have singularity free bouncing models. The bound is saturated for
co-dimension one branes dominated universes.Comment: Talk presented at the XXVIII Spanish Relativity Meeting E.R.E. 2005,
Oviedo, September 6-10, 2005, to be published by AIP Conference Proceedings,
4 page
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Human-display interaction technology: Emerging remote interfaces for pervasive display environments
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.We're living in a world where information processing isn't confined to desktop computers - it's being integrated into everyday objects and activities. Pervasive computation is human centered: it permeates our physical world, helping us achieve goals and fulfill our needs with minimum effort by exploiting natural interaction styles. Remote interaction with screen displays requires a sensor-based, multimodal, touchless approach. For example, by processing user hand gestures, this paradigm removes constraints requiring physical contact and permits natural interaction with tangible digital information. Such touchless interaction can be multimodal, exploiting the visual, auditory, and olfactory senses.Ministerio de Educación y Ciencia and Amper Sistemas, SA
Epidermal growth factor coordinately regulates the expression of prostaglandin G/H synthase and cytosolic phospholipase A2 genes in embryonic mouse cells.
Confluent, primary cultures of mouse embryo palate mesenchyme (MEPM) cells are refractory to activation of phospholipase A2 (PLA2) by the calcium ionophore A23187. However, treatment of these cultures with epidermal growth factor (EGF) permits the cells to activate PLA2 in response to A23187. We have developed this finding by exploring molecular mechanisms by which growth factors modulate mobilization and metabolism of arachidonic acid. We found chronic treatment (\u3e 6 h) of confluent MEPM cells with EGF (a) increases their ability to metabolize exogenous arachidonic acid to prostaglandin E2 (PGE2) and (b) stimulated constitutive expression of activities of PLA2 and cyclooxygenase (CyOx). Immunoprecipitation of [35S]proteins and Western blot analysis revealed EGF treatment stimulated synthesis and accumulation of PLA2c, CyOx-1, and CyOx-2. Northern hybridization analysis revealed EGF increased the steady-state levels of a transcript for the high molecular weight, cytosolic PLA2 (PLA2c), and both the 2.8- and 4.2-kb transcripts for CyOx-1 and CyOx-2, respectively. In vitro nuclear transcription assays showed a parallel increase in the transcription rate of the genes corresponding to CyOx-1 and PLA2c, but not CyOx-2, in response to EGF. Treatment with EGF had no effect on either synthesis of the low molecular weight, group II PLA2, accumulation of its transcript, or the transcription rate of its gene. Coordinate regulation of activities of PLA2 and CyOx in response to EGF did not parallel the mitogenic effects of EGF on confluent MEPM cells
Regulation of transforming growth factor-beta 1 gene expression by glucocorticoids in normal human T lymphocytes.
Glucocorticoids (GC) modulate immune function in a number of ways, including suppression of T cell proliferation and other IL-2-mediated T cell functions. These inhibitory effects are similar to those induced by transforming growth factor-beta 1 (TGF-beta 1), a cytokine with potent T cell inhibiting activities. We examined the hypothesis that GC effects may be at least partially achieved through modulation of the expression of the TGF-beta 1 gene in activated T cells. Normal T cells were cultured with or without purified phytohemagglutinin (PHA-p) and 4 beta-phorbol 12-myristate 13-acetate (PMA) in the presence or absence of the synthetic GC, dexamethasone (100-200 micrograms/ml). The production of latent and active forms of TGF beta by these cells were analyzed by immunoblotting and bioassays. The steady-state levels of TGF-beta 1 mRNA were analyzed in total RNA from these cells by Northern hybridizations using a human TGF-beta 1 cDNA. The results showed that dexamethasone caused an increase in TGF beta production and a dose-dependent two to fourfold increase in TGF-beta 1 mRNA in activated as well as in unstimulated T cells, 1 h after exposure of the cultures to the steroid. The increase in TGF-beta 1 mRNA levels by dexamethasone was further potentiated two to threefold by cycloheximide, suggesting that the steroid effect may be due to inhibition of the synthesis of proteins that decrease TGF-beta 1 gene transcription or the stability of its transcripts. Finally, in vitro nuclear transcription studies indicated the dexamethasone effects on TGF-beta 1 gene expression to be largely transcriptional
Non-equilibrium transport through a disordered molecular nanowire
We investigate the non-equilibrium transport properties of a disordered
molecular nanowire. The nanowire is regarded as a quasi-one-dimensional organic
crystal composed of self-assembled molecules. One orbital and a single random
energy are assigned to each molecule while the intermolecular coupling does not
fluctuate. Consequently, electronic states are expected to be spatially
localized. We consider the regime of strong localization, namely, the
localization length is smaller than the length of the molecular wire.
Electron-vibron interaction, taking place in each single molecule, is also
taken into account. We investigate the interplay between disorder and
electron-vibron interaction in response to either an applied electric bias or a
temperature gradient. To this end, we calculate the electric and heat currents
when the nanowire is connected to leads, using the Keldysh non-equilibrium
Green's function formalism. At intermediate temperature, scattering by disorder
dominates both charge and heat transport. We find that the electron-vibron
interaction enhances the effect of the disorder on the transport properties due
to the exponential suppression of tunneling
Hyperonic crystallization in hadronic matter
Published in Hadrons, Nuclei and Applications, World Scientific, Singapore,
Proc.of the Conference Bologna2000. Structure of the Nucleus at the Dawn of the
Century, G. Bonsignori, M. Bruno, A. Ventura, D. Vretenar Editors, pag. 319.Comment: 4 pages, 2figure
A Quantum Lovasz Local Lemma
The Lovasz Local Lemma (LLL) is a powerful tool in probability theory to show
the existence of combinatorial objects meeting a prescribed collection of
"weakly dependent" criteria. We show that the LLL extends to a much more
general geometric setting, where events are replaced with subspaces and
probability is replaced with relative dimension, which allows to lower bound
the dimension of the intersection of vector spaces under certain independence
conditions. Our result immediately applies to the k-QSAT problem: For instance
we show that any collection of rank 1 projectors with the property that each
qubit appears in at most of them, has a joint satisfiable
state.
We then apply our results to the recently studied model of random k-QSAT.
Recent works have shown that the satisfiable region extends up to a density of
1 in the large k limit, where the density is the ratio of projectors to qubits.
Using a hybrid approach building on work by Laumann et al. we greatly extend
the known satisfiable region for random k-QSAT to a density of
. Since our tool allows us to show the existence of joint
satisfying states without the need to construct them, we are able to penetrate
into regions where the satisfying states are conjectured to be entangled,
avoiding the need to construct them, which has limited previous approaches to
product states.Comment: 19 page
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