We propose a model for noncommutative quantum cosmology by means of a deformation of minisuperspace. For the Kantowski-Sachs metric we are able to find the exact wave function. We construct wave packets and show that new quantum states that "compete" to be the most probable state appear, in clear contrast with the commutative case. A tunneling process could be possible among these states.PACS numbers: 04.60. Kz, 11.10.Lm, 11.25.Sq, 98.80.Hw The old proposal of noncommutativity in space-time [1] has been recently subject of renewed interest (see reviews [2,3,4]). This is a consequence of the developments in M(atrix) theory [5] and string theory, from which noncommutativity arises in the low energy effective field theory on a D-brane in a constant background B-field [6,7,8,9].One of the most exciting recent applications of the idea of a minimal size to field theory, is that concerning the description of Yang-Mills instantons in four dimensional noncommutative spacetimes. It has been shown that in these spaces instantons acquire an effective size in terms of the noncommutativity parameter θ. As a consequence, the moduli space of noncommutative instantons no longer has the singularities corresponding to small instantons [10]. This effect has a nice stringy interpretation [9].Noncommutative gravity has been considered in [11,12,13]. In particular in reference [13] a deformed Einstein gravity is constructed by using the Seiberg-Witten map [9], gauging the noncommutative ISO(3,1) group. Some aspects of noncommutative 2 + 1-dimensional Chern-Simons gravity have been also studied [14,15].One of the puzzles in quantum gravity is the measurement of length, which seems to be limited to distances greater than the Planck length L P , because to locate a particle we would need an energy greater than the Planck mass M P . The corresponding gravitational field will have an horizon given by the Schwarzschild radius R = 2GMP c 2 = 2L P and, whatever happens inside, this radius is shielded and therefore a minimal size should exist for quanta of space and time configuration.Consequently, at very early times of the universe, before the Planck time, nontrivial effects of noncommutativity can be expected.In the study of homogeneous universes, the metric depends only on the time parameter. Thus, the space dependence can be integrated out in the action and a model with a finite dimensional configuration space arises, called also minisuperspace, whose variables are the three-metric components. These theories have been considered by themselves, and their quantization is performed following the rules of quantum mechanics.The minisuperspace construction is a procedure to define quantum cosmology models in the search to describe the quantum behavior of the very early stages of the universe [16,17]. By defining these models one necessarily freezes out degrees of freedom, so that these are only simple and probably approximate models of full quantum gravity at Planckian times. Formally, a kind of Klein Gordon equation arises in these models, ...

No abstract

Starting from a self-dual formulation of gravity, we obtain a noncommutative theory of pure Einstein theory in four dimensions. In order to do that, we use Seiberg-Witten map. It is shown that the noncommutative torsion constraint is solved by the vanishing of commutative torsion.Finally, the noncommutative corrections to the action are computed up to second order. * Electronic address: compean@fis.cinvestav.mx † Electronic address: octavio@ifug3.ugto.mx ‡ Permanent address:

Mast cell activation through the high affinity IgE receptor (FcepsilonRI) is a critical component of atopic inflammation. The cytokine TGF-beta1 has been shown to inhibit IgE-dependent mast cell activation, possibly serving to dampen mast cell-mediated inflammatory responses. We present proof that TGF-beta1 inhibits mast cell FcepsilonRI expression through a reversible pathway that diminishes protein, but not mRNA, expression of the FcepsilonRI subunit proteins alpha, beta, and gamma. The stability of the expressed proteins and the assembled cell surface complex was unaltered by TGF-beta1 treatment. However, TGF-beta1 decreased the rate of FcepsilonRI beta-chain synthesis, arguing that this inhibitory cytokine exerts its effects at the level of mRNA translation. TGF-beta1 consistently diminished FcepsilonRI expression on cultured human or mouse mast cells as well as freshly isolated peritoneal mast cells. The related cytokines, TGF-beta2 and TGF-beta3, had similar effects. We propose that TGF-beta1 acts as a negative regulator of mast cell function, in part by decreasing FcepsilonRI expression.

No abstract

In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole.

Herpes simplex virus type 1 (HSV-1) is neurotropic and enters a latent state lasting the lifetime of the host. This pathogen has recently been proposed as a risk factor for Alzheimer's disease (AD) in conjunction with apolipoprotein E4 (ApoE4). In a murine acute infection model, we showed that viral neuroinvasiveness depends directly on the overall ApoE dosage and especially on the presence of isoform ApoE4. If an interaction between ApoE and HSV-1 is involved in AD, it may occur during latency rather than during acute infection. Certainly, ApoE plays an important role in late-onset AD, i.e., at a time in life when the majority of people harbor HSV-1 in their nervous system. In the present work, wild-type, APOE knockout, APOE3, and APOE4 transgenic mice were used to analyze the influence of the ApoE profile on the levels of latent virus DNA. The knockout mice had significantly lower concentrations of the virus in the nervous system than the wild-type mice, while the APOE4 mice had very high levels in the brain compared to the APOE3 animals. ApoE4 seems to facilitate HSV-1 latency in the brain much more so than ApoE3. The APOE dosage correlated directly with the HSV-1 DNA concentration in the brain, strengthening the hypothesis that HSV-1, together with ApoE, might be involved in AD.

We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn could help to understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to which GRBs accelerate particles