8,695 research outputs found
A New Handle on de Sitter Compactifications
We construct a large new class of de Sitter (and anti de Sitter) vacua of
critical string theory from flux compactifications on products of Riemann
surfaces. In the construction, the leading effects stabilizing the moduli are
perturbative. We show that these effects self-consistently dominate over
standard estimates for further and quantum corrections, via
tuning available from large flux and brane quantum numbers.Comment: 26 pages, harvmac big. v2: Correction generalizing specific
ingredients required for tunable negative term; conclusions and structure of
potential unchange
Inelastic electron relaxation rates caused by Spin M/2 Kondo Impurities
We study a spin S=M/2--Kondo system coupled to electrons in an arbitrary
nonequilibrium situation above Kondo temperature. Coupling to hot electrons
leads to an increased inverse lifetime of pseudo particles, related to the
Korringa width. This in turn is responsible for the increased inelastic
relaxation rates of the electronic system. The rates are related to spin--spin
correlation functions which are determined using a projection operator
formalism. The results generalize recent findings for S=1/2--Kondo impurities
which have been used to describe energy relaxation experiments in disordered
mesoscopic wires.Comment: Brief Report, 4 page
A prelysosomal compartment sequesters membrane-impermeant fluorescent dyes from the cytoplasmic matrix of J774 macrophages
After the membrane impermeant dye Lucifer Yellow is introduced into the cytoplasmic matrix of J774 cells, the dye is sequestered within cytoplasmic vacuoles and secreted into the extracellular medium. In the present work we studied the intracellular transport of Lucifer Yellow in J774 macrophages and the nature of the cytoplasmic vacuoles into which this dye is sequestered. When the lysosomal system of J774 cells was prelabeled with a Texas red ovalbumin conjugate and Lucifer Yellow was then loaded into the cytoplasm of the cells by ATP-mediated permeabilization of the plasma membrane, the vacuoles that sequestered Lucifer Yellow 30 min later were distinct from the Texas red-stained lysosomes. After an additional 30 min Lucifer Yellow and Texas red colocalized in the same membrane bound compartments, indicating that the Lucifer Yellow had been delivered to lysosomes. We next prelabeled the plasma membrane of J774 cells with anti-macrophage antibody and Texas red protein A before Lucifer Yellow was loaded into the cells. The phase-lucent vacuoles that subsequently sequestered Lucifer Yellow also stained with Texas red, showing that they were part of the endocytic pathway. J774 cells were fractionated on percoll density gradients either 15 or 60 min after Lucifer Yellow was introduced into the cytoplasmic matrix of the cells. In cells fractionated after 15 min, Lucifer Yellow was contained within the fractions of light buoyant density that contain plasma membrane and endosomes; the dye later appeared in vesicles of higher density which contained lysosomes. Secretion of Lucifer Yellow from the cytoplasmic matrix of J774 cells is inhibited by the organic anion transport blocker probenecid. We found that probenecid also reversibly inhibited sequestration of dye, indicating that sequestration of dye within cytoplasmic vacuoles was also mediated by organic anion transporters. These studies show that the vacuoles that sequester Lucifer Yellow from the cytoplasmic matrix of J774 cells possess the attributes of endosomes. Thus, in addition to their role in sorting of membrane bound and soluble substances, macrophage endosomes may play a role in the accumulation and transport of molecules resident in the soluble cytoplasm
Traitement multimodal de l’agressivité et de la violence chez des personnes souffrant de psychose
Dans cet article, les auteurs décrivent les traitements non pharmacologiques qui ont fait preuve d’efficacité pour réduire l’agressivité et la violence chez les personnes souffrant de psychose. Ils présentent ensuite une approche de formulation/planification du traitement qui aborde les influences étiologiques complexes, et les facteurs multiples qui jouent sur le maintien du comportement agressif chez ces patients. Finalement, ils présentent en exemple un cas où l’on se sert de cette approche.In this article, the authors offer a description of nonpharmacological treatments which have demonstrated effectiveness in reducing aggression and violence in patient with psychosis ; present a case formulation/treatment planning approach which addresses the complex etiological influences and multiple factors affecting maintenance of aggressive behavior in PI ; finally, they provide a case example of this approach.En este artículo, los autores describen los tratamientos no farmacológicos que han demostrado ser eficaces en la reducción de la agresividad y la violencia en las personas que sufren de psicosis. Enseguida, presentan un enfoque de formulación/planificación del tratamiento que aborda las influencias etiológicas complejas y los múltiples factores que tienen un efecto en el mantenimiento del comportamiento agresivo en estos pacientes. Finalmente, presentan como ejemplo un caso en el que se sirven de este enfoque.Neste artigo, os autores descrevem os tratamentos não farmacológicos que provaram ser eficazes para reduzir a agressividade e a violência nas pessoas que sofrem de psicose. Eles apresentam em seguida uma abordagem de formulação/planificação do tratamento que aborda as influências etimológicas complexas, e os fatores múltiplos que influenciam sobre a manutenção do comportamento agressivo nestes pacientes. Finalmente, eles apresentam o exemplo de um caso onde esta abordagem foi utilizada
AdS Bubbles, Entropy and Closed String Tachyons
We study the conjectured connection between AdS bubbles (AdS solitons) and
closed string tachyon condensations. We confirm that the entanglement entropy,
which measures the degree of freedom, decreases under the tachyon condensation.
The entropies in supergravity and free Yang-Mills agree with each other
remarkably. Next we consider the tachyon condensation on the AdS twisted circle
and argue that its endpoint is given by the twisted AdS bubble, defined by the
double Wick rotation of rotating black 3-brane solutions. We calculated the
Casimir energy and entropy and checked the agreements between the gauge and
gravity results. Finally we show an infinite boost of a null linear dilaton
theory with a tachyon wall (or bubble), leads to a solvable time-dependent
background with a bulk tachyon condensation. This is the simplest example of
spacetimes with null boundaries in string theory.Comment: 45 pages, 6 figures, harvmac, eq.(2.16) corrected, references adde
Localization of Bulk Form Fields on Dilatonic Domain Walls
We study the localization properties of bulk form potentials on dilatonic
domain walls. We find that bulk form potentials of any ranks can be localized
as form potentials of the same ranks or one lower ranks, for any values of the
dilaton coupling parameter. For large enough values of the dilaton coupling
parameter, bulk form potentials of any ranks can be localized as form
potentials of both the same ranks and one lower ranks.Comment: 9 pages, LaTeX, reference adde
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