376 research outputs found
The Spacetime Structure of Open Quantum Relativity
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
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 data
A new calculation of the 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 =100 GeV (1 TeV) signal cannot be increased by more than a factor 6 (40)
without overrunning PAMELA data. Annihilation through the channel is
also inspected and cross-checked with 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
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
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 due to a Higher Dimensional spacetime
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 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
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
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
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
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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