374 research outputs found

    The Spacetime Structure of Open Quantum Relativity

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    In the framework of the Open Quantum Relativity, we discuss the geodesic and chronological structures related to the embedding procedure and dimensional reduction from 5D to 4D spacetime. The emergence of an extra-force term, the deduction of the masses of particles, two-time arrows and closed time-like solutions are considered leading to a straightforward generalization of causality principle

    ANTI HYPERGLYCAEMIC AND ANTIOXIDANT ACTIVITY OF CATUNAREGAM SPINOSA (THUNB) AGAINST DEXAMETHASONE INDUCED DIABETES IN RATS

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    Objective: The study was aimed at evaluating the folkloric use of the Catunaregam spinosa (Thunb) bark for its hypoglycaemic and antioxidant activity against dexamethasone-induced diabetes in wistar rats. Methods: Diabetes was induced in wistar rats by dexamethasone administration 10 mg/kg, b. wt., s. c for 11 consecutive days to all group animals (except Group I). After confirmation of diabetes, the animals were divided into 5 groups (n=6). Group I: Vehicle control treated with normal saline only, Group II: Diabetic control treated with dexamethasone only, Group III: Standard control treated with dexamethasone plus glibenclamide (5 mg/kg, b. wt., p. o), Group IV and V: Test control received dexamethasone plus ethanolic extract of Catunaregam spinosa (EECS) at graded doses of 200 mg/kg, b. wt. and 400 mg/kg, b. wt., p. o for 21days respectively. On the last day of the experiment, the effect of Catunaregam spinosa bark was measured by estimating the biochemical and antioxidant parameters. Results: There was a significant alteration in the serum glucose, HbA1c, total proteins, serum lipid profile and tissue antioxidant parameters in dexamethasone-treated animals when compared to the normal control rats. In test groups treated with glibenclamide and EECS, it was significantly ameliorated the altered parameters such as serum glucose, HbA1c, total proteins, serum lipid profile and the antioxidant parameters like SOD, CAT, GSH and MDA when compared to dexamethasone-treated animals with evidence of histopathological studies of the pancreas. Conclusion: The results indicated that the ethanolic extract of Catunaregam Spinosa (Thunb) bark has shown the hypoglycemic and antioxidant property

    Constraints on WIMP Dark Matter from the High Energy PAMELA pˉ/p\bar{p}/p data

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    A new calculation of the pˉ/p\bar{p}/p ratio in cosmic rays is compared to the recent PAMELA data. The good match up to 100 GeV allows to set constraints on exotic contributions from thermal WIMP dark matter candidates. We derive stringent limits on possible enhancements of the WIMP \pbar flux: a mWIMPm_{\rm WIMP}=100 GeV (1 TeV) signal cannot be increased by more than a factor 6 (40) without overrunning PAMELA data. Annihilation through the W+W−W^+W^- channel is also inspected and cross-checked with e+/(e−+e+)e^+/(e^-+e^+) data. This scenario is strongly disfavored as it fails to simultaneously reproduce positron and antiproton measurements.Comment: 5 pages, 5 figures, the bibliography has been updated, minor modifications have been made in the tex

    Gravitational Cherenkov Radiation from Extended Theories of Gravity

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    We linearize the field equations for higher order theories of gravity that contain scalar invariants other than the Ricci scalar. We find that besides a massless spin-2 field (the standard graviton), the theory contains also spin-0 and spin-2 massive modes with the latter being, in general, ghost modes. The rate at which such particles would emit gravitational Cherenkov radiation is calculated for some interesting physical cases.Comment: 6 pages, to appear in Mod. Phys. Lett. A. arXiv admin note: text overlap with arXiv:0911.3094, arXiv:1105.619

    Antimatter research in Space

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    Two of the most compelling issues facing astrophysics and cosmology today are to understand the nature of the dark matter that pervades the universe and to understand the apparent absence of cosmological antimatter. For both issues, sensitive measurements of cosmic-ray antiprotons and positrons, in a wide energy range, are crucial. Many different mechanisms can contribute to antiprotons and positrons production, ranging from conventional reactions up to exotic processes like neutralino annihilation. The open problems are so fundamental (i.e.: is the universe symmetric in matter and antimatter ?) that experiments in this field will probably be of the greatest interest in the next years. Here we will summarize the present situation, showing the different hypothesis and models and the experimental measurements needed to lead to a more established scenario.Comment: 10 pages, 7 figures, Invited talk at the 18th European Cosmic Ray Symposium, Moscow, July 2002, submitted to Journal of Physics

    On The 5D Extra-Force according to Basini-Capozziello-Leon Formalism and five important features: Kar-Sinha Gravitational Bending of Light, Chung-Freese Superluminal Behaviour, Maartens-Clarkson Black Strings, Experimental measures of Extra Dimensions on board International Space Station(ISS) and the existence of the Particle ZZ due to a Higher Dimensional spacetime

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    We use the Conformal Metric as described in Kar-Sinha work on Gravitational Bending of Light in a 5D Spacetime to recompute the equations of the 5D Force in Basini-Capozziello-Leon Formalism and we arrive at a result that possesses some advantages. The equations of the Extra Force as proposed by Leon are now more elegant in Conformal Formalism and many algebraic terms can be simplified or even suppressed. Also we recompute the Kar-Sinha Gravitational Bending of Light affected by the presence of the Extra Dimension and analyze the Superluminal Chung-Freese Features of this Formalism describing the advantages of the Chung-Freese BraneWorld when compared to other Superluminal spacetime metrics(eg:Warp Drive) and we describe why the Extra Dimension is invisible and how the Extra Dimension could be made visible at least in theory.We also examine the Maartens-Clarkson Black Holes in 5D(Black Strings) coupled to massive Kaluza-Klein graviton modes predicted by Extra Dimensions theories and we study experimental detection of Extra Dimensions on-board LIGO and LISA Space Telescopes.We also propose the use of International Space Station(ISS) to measure the additional terms(resulting from the presence of Extra Dimensions) in the Kar-Sinha Gravitational Bending of Light in Outer Space to verify if we really lives in a Higher Dimensional Spacetime.Also we demonstrate that Particle ZZ can only exists if the 5D spacetime exists.Comment: Withdrawn: author no longer wishes to post work on arXi

    Kaluza-Klein Dark Matter and Galactic Antiprotons

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    Extra dimensions offer new ways to address long-standing problems in beyond the standard model particle physics. In some classes of extra-dimensional models, the lightest Kaluza-Klein particle is a viable dark matter candidate. In this work, we study indirect detection of Kaluza-Klein dark matter via its annihilation into antiprotons. We use a sophisticated galactic cosmic ray diffusion model whose parameters are fully constrained by an extensive set of experimental data. We discuss how fluxes of cosmic antiprotons can be used to exclude low Kaluza-Klein masses.Comment: 14 pages, 7 figures, 3 table

    Deriving the mass of particles from Extended Theories of Gravity in LHC era

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    We derive a geometrical approach to produce the mass of particles that could be suitably tested at LHC. Starting from a 5D unification scheme, we show that all the known interactions could be suitably deduced as an induced symmetry breaking of the non-unitary GL(4)-group of diffeomorphisms. The deformations inducing such a breaking act as vector bosons that, depending on the gravitational mass states, can assume the role of interaction bosons like gluons, electroweak bosons or photon. The further gravitational degrees of freedom, emerging from the reduction mechanism in 4D, eliminate the hierarchy problem since generate a cut-off comparable with electroweak one at TeV scales. In this "economic" scheme, gravity should induce the other interactions in a non-perturbative way.Comment: 30 pages, 1 figur

    Diffractive Interaction and Scaling Violation in pp->pi^0 Interaction and GeV Excess in Galactic Diffuse Gamma-Ray Spectrum of EGRET

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    We present here a new calculation of the gamma-ray spectrum from pp->pi^0 in the Galactic ridge environment. The calculation includes the diffractive pp interaction and incorporates the Feynman scaling violation for the first time. Galactic diffuse gamma-rays come, predominantly, from pi^0->gamma gamma in the sub-GeV to multi-GeV range. Hunter et al. found, however, an excess in the GeV range ("GeV Excess") in the EGRET Galactic diffuse spectrum above the prediction based on experimental pp->pi^0 cross-sections and the Feynman scaling hypothesis. We show, in this work, that the diffractive process makes the gamma-ray spectrum harder than the incident proton spectrum by ~0.05 in power-law index, and, that the scaling violation produces 30-80% more pi^0 than the scaling model for incident proton energies above 100GeV. Combination of the two can explain about a half of the "GeV Excess" with the local cosmic proton (power-law index ~2.7). The excess can be fully explained if the proton spectral index in the Galactic ridge is a little harder (~0.2 in power-law index) than the local spectrum. Given also in the paper is that the diffractive process enhances e^+ over e^- and the scaling violation gives 50-100% higher p-bar yield than without the violation, both in the multi-GeV range.Comment: 35 pages, 11 figures, to appear in Astrophysical Journa

    Nanoplastics impair in vitro swine granulosa cell functions

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    Soil, water and air pollution by plastic represents an issue of great concern since the particles produced by degradation of plastic materials can be ingested by animals and humans, with still uncertain health consequences. As a contribution on this crucial subject, the present work reports an investigation on the in vitro effects of different concentrations of polystyrene nanoplastics (5, 25 and 75 ÎŒg/mL) on swine granulosa cells, a model of endocrine reproductive cells. In particular, cell growth (BrDU incorporation and ATP production), steroidogenesis (17-ÎČ estradiol and progesterone secretion) and redox status (superoxide and nitric oxide production, enzymatic and non-enzymatic scavenging activity) were studied. Nanoplastics, at the highest concentration, stimulated cell proliferation (P < 0.05), while cell viability resulted unaffected. Steroidogenesis were disrupted (P < 0.05). Both enzymatic and non-enzymatic scavenging activity were increased after exposure at the highest nanoplastic dose (P < 0.05, P < 0.001). Nitric oxide secretion was increased by 25 and 75 ÎŒg/mL (P < 0.05) while superoxide generation was stimulated (P < 0.001) only by the highest concentration tested. Taken together, main features of cultured swine granulosa cells resulted affected by exposure to nanoplastics. These results raise concerns since environment nanoplastic contamination can represents a serious threat to animal and human health
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