51 research outputs found
Coherent States of Harmonic Oscillator and Generalized Uncertainty Principle
In this paper dynamics and quantum mechanical coherent states of a simple
harmonic oscillator are considered in the framework of Generalized Uncertainty
Principle(GUP). Equations of motion for simple harmonic oscillator are derived
and some of their new implications are discussed. Then coherent states of
harmonic oscillator in the case of GUP are compared with relative situation in
ordinary quantum mechanics. It is shown that in the framework of GUP there is
no considerable difference in definition of coherent states relative to
ordinary quantum mechanics. But, considering expectation values and variances
of some operators, based on quantum gravitational arguments one concludes that
although it is possible to have complete coherency and vanishing broadening in
usual quantum mechanics, gravitational induced uncertainty destroys complete
coherency in quantum gravity and it is not possible to have a monochromatic ray
in principle.Comment: 12 pages, no figur
Energy conditions in f(T) gravity with higher-derivative torsion terms
We study the energy conditions in the framework of the modi- fied gravity
with higher-derivative torsional terms in the action. We discuss the viability
of the model by studying the energy conditions in terms of the cosmographical
parameters like Hubble, deceleration, jerk, snap and lerk parameters. In
particular, We consider two spe- cific models that are proposed in literature
and examine the viability bounds imposed by the weak energy condition
Evolution of Gravitational Waves in Non-minimal Coupling Between Geometry and Matter Theories of Gravity
We consider some specific models of non-minimal matter-geometry coupling
theories and investigate the propagation of the gravitational waves in them.
Extracting the temporal evolution of the gravitational wave equation within the
framework of a flat FRW universe with a perfect fluid distribution, we analyze
the waveforms traveling during the time. We find that while both the amplitude
and frequency of the GWs decay with time in all considered models, the rate of
reduction is highly sensitive to the values of the equation of state parameter
and input parameters of the considered models.Comment: 26 pages, 22 figures; to appear in Physics of the Dark Univers
Amelioration of amyloid beta (Aβ1-40) neurotoxicity by administration of silibinin; a behavioral and biochemical assessment
Objective(s): Alzheimer’s disease (AD), the most common cause of dementia, is one of the leading causes of morbidity and death in the world. Currently, treatment mostly used to slow down the disease progression. Herbal remedies are considered by many in the community as a natural and safe treatment with fewer side effects. Silibinin, the active ingredient of Silybum marionum, has anti-oxidant, neurotrophic and neuroprotective characteristics. Therefore, here, the effect of different doses of Silibinin extract on oxidative stress and expression of neurotrophic factors was investigated. Materials and Methods: Forty eight male Wistar rats were randomly divided into sham, lesion; Aβ1-40 injection, lesion-treatment; Aβ1-40 injection followed by different doses of silibinin (50, 100, 200 mg / kg) through gavage and lesion-vehicle group; Aβ1-40 injection + vehicle of silibinin. Morris water Maze (MWM) was done 28 days after the last treatment. Hippocampal tissue was removed for biochemical analysis. Production of nitric oxide (NO) and reactive oxygen species (ROS), expression of BDNF/VEGF and cell viability were measured using Griess, fluorimetry, Western blotting and MTT techniques.  Results: Different concentrations of silibinin improved behavioral performance in animals. Higher doses of Silibinin could improve memory and learning function through MWM. Also, increasing the concentration of silibinin resulted in decreased ROS and NO production in a dose-dependent manner.Conclusion: Consequently, silibinin may act as a potential candidate for alleviating symptoms of AD
The impact of irritable bowel syndrome on health-related quality of life in women with polycystic ovary syndrome
Background: The objectives of this study were to compare the prevalence and quality of life (QOL) of irritable bowel syndrome (IBS) in women with polycystic ovary syndrome (PCOS) compared with healthy women.
Methods: This was a case-control study of 201 women recruited at an infertility clinic in Iran. The control group were healthy women (n = 100) and the comparison group, women with PCOS (n = 101). Data were collected by clinical Rome III criteria to determine the IBS, Bristol scale for stool consistency and IBS QOL.
Results: The reporting of IBS symptoms were higher in PCOS (20.7%) than control group (11%) (P = 0.05). The IBS QOL score in the IBS + PCOS group was lower than other groups (IBS+ non PCOS, non IBS + PCOS, non IBS+ non PCOS; scores in food avoidance and worries about health domains were significant (P < 0.01).
Conclusions: We conclude that having PCOS and an increased level of LH/FSH tends to cause IBS symptoms. IBS + PCOS women experience significant impaired quality of life scores particularly in relation to worries about health and food avoidance. These results offer further insights into IBS in PCOS women and their functional status and wellbeing
Wormhole Geometries In Gravity
We study wormhole solutions in the framework of f (R,T) gravity where R is
the scalar curvature, and T is the trace of the stress-energy tensor of the
matter. We have obtained the shape function of the wormhole by specifying an
equation of state for the matter field and imposing the flaring out condition
at the throat. We show that in this modified gravity scenario, the matter
threading the wormhole may satisfy the energy conditions, so it is the
effective stress-energy that is responsible for violation of the null energy
condition.Comment: 9 pages, 4 figures, published version, references adde
Some Aspects of Minimal Length Quantum Mechanics
String theory, quantum geometry, loop quantum gravity and black hole physics
all indicate the existence of a minimal observable length on the order of
Planck length. This feature leads to a modification of Heisenberg uncertainty
principle. Such a modified Heisenberg uncertainty principle is referred as
gravitational uncertainty principle(GUP) in literatures. This proposal has some
novel implications on various domains of theoretical physics. Here, we study
some consequences of GUP in the spirit of Quantum mechanics. We consider two
problem: a particle in an one-dimensional box and momentum space wave function
for a "free particle". In each case we will solve corresponding perturbational
equations and compare the results with ordinary solutions.Comment: 9 pages, one eps figur
Observational Constraints on the Normal Branch of a Warped DGP Cosmology
We investigate observational constraints on the normal branch of the warped
DGP braneworld cosmology by using observational data from Type Ia Supernovae
(SNIa), Baryon Acoustic Oscillations (BAO), Cosmic Microwave Background (CMB)
and Baryon Gas Mass Fraction of cluster of galaxies. The best fit values of
model free parameters are: and
at confidence interval by using Gold
sample SNIa+CMB shift parameter+BAO+Gas mass fraction of baryons in cluster of
galaxies. The results for essence sample SNIa combined with CMB shift
parameter, BAO and Baryon Gas mass fraction correspont to: and at 68.3% confidence
interval. We determine the age of the universe by using these best fit values.
We also study the effective cosmological dynamics on the brane via an effective
equation of state parameter and the deceleration parameter to conclude that an
effective phantom-like behavior arises in this scenario.Comment: 16 pages, 10 figures, to appear in New Astronom
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