2,941,257 research outputs found
Vaidya Spacetime in Massive Gravity's Rainbow
In this paper, we will analyze the energy dependent deformation of massive
gravity using the formalism of massive gravity's rainbow. So, we will use the
Vainshtein mechanism and the dRGT mechanism for the energy dependent massive
gravity, and thus analyze a ghost free theory of massive gravity's rainbow. We
study the energy dependence of a time-dependent geometry, by analyzing the
radiating Vaidya solution in this theory of massive gravity's rainbow. The
energy dependent deformation of this Vaidya metric will be performed using
suitable rainbow functions.Comment: 13 pages, 8 figure
Spin state readout by quantum jump technique: for the purpose of quantum computing
Utilizing the Pauli-blocking mechanism we show that shining circular
polarized light on a singly-charged quantum dot induces spin dependent
fluorescence. Employing the quantum-jump technique we demonstrate that this
resonance luminescence, due to a spin dependent optical excitation, serves as
an excellent readout mechanism for measuring the spin state of a single
electron confined to a quantum dot.Comment: 11 pages, 4 eps figure
Liberating the Inflaton from Primordial Spectrum Constraints
I discuss a mechanism that renders the spectral index of the primordial
spectrum and the inflationary stage independent of each other. If a scalar
field acquires an appropriate time-dependent mass, it is possible to generate
an adiabatic, Gaussian scale invariant spectrum of density perturbations during
any stage of inflation. As an illustration, I present a simple model where the
time-dependent mass arises from the coupling of the inflaton to a second
scalar. The mechanism I propose might help to implement a successful
inflationary scenario in particle physics theories that do not yield slow-roll
potentials.Comment: 7 two-column pages, 1 figure. Uses RevTeX
Repression of DNA-binding dependent glucocorticoid receptor-mediated gene expression
The glucocorticoid receptor (GR) affects the transcription of genes involved in diverse processes, including energy metabolism and the immune response, through DNA-binding dependent and independent mechanisms. The DNA-binding dependent mechanism occurs by direct binding of GR to glucocorticoid response elements (GREs) at regulatory regions of target genes. The DNA-binding independent mechanism involves binding of GR to transcription factors and coactivators that, in turn, contact DNA. A small molecule that competes with GR for binding to GREs could be expected to affect the DNA-dependent pathway selectively by interfering with the protein-DNA interface. We show that a DNA-binding polyamide that targets the consensus GRE sequence binds the glucocorticoid-induced zipper (GILZ) GRE, inhibits expression of GILZ and several other known GR target genes, and reduces GR occupancy at the GILZ promoter. Genome-wide expression analysis of the effects of this polyamide on a set of glucocorticoid-induced and -repressed genes could help to elucidate the mechanism of GR regulation for these genes
How parametric resonance mechanism follows quench mechanism in disoriented chiral condensate
We show how parametric resonance mechanism follows quench mechanism in the
classical linear sigma model. The parametric resonance amplifies long
wavelength modes of the pion for more than . The shifting from the
quench mechanism to the parametric resonance mechanism is described by a time
dependent quantity. After the quench mechanism is over, that quantity has an
oscillating part, which causes the parametric resonance. Since its frequency is
: pion mass), very long wavelength modes such as k = 40 MeV
of the pion are amplified by the parametric resonance.Comment: LaTeX, 10 page
α8β1 integrin regulates nutrient absorption through an Mfge8-PTEN dependent mechanism.
Coordinated gastrointestinal smooth muscle contraction is critical for proper nutrient absorption and is altered in a number of medical disorders. In this work, we demonstrate a critical role for the RGD-binding integrin α8β1 in promoting nutrient absorption through regulation of gastrointestinal motility. Smooth muscle-specific deletion and antibody blockade of α8 in mice result in enhanced gastric antral smooth muscle contraction, more rapid gastric emptying, and more rapid transit of food through the small intestine leading to malabsorption of dietary fats and carbohydrates as well as protection from weight gain in a diet-induced model of obesity. Mechanistically, ligation of α8β1 by the milk protein Mfge8 reduces antral smooth muscle contractile force by preventing RhoA activation through a PTEN-dependent mechanism. Collectively, our results identify a role for α8β1 in regulating gastrointestinal motility and identify α8 as a potential target for disorders characterized by hypo- or hyper-motility
Electronic conduction in multi-walled carbon nanotubes: Role of intershell coupling and incommensurability
Geometry incommensurability between weakly coupled shells in multi-walled
carbon nanotubes is shown to be the origin of unconventional electronic
conduction mechanism, power-law scaling of the conductance, and remarkable
magnetotransport and low temperature dependent conductivity when the dephasing
mechanism is dominated by weak electron-electron coupling
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