Neutrino coupling to cosmological background: A review on gravitational Baryo/Leptogenesis

In this work we review the theories of origin of matter-antimatter asymmetry in the Universe. The general conditions for achieving baryogenesis and leptogenesis in a CPT conserving field theory have been laid down by Sakharov. In this review we discuss scenarios where a background scalar or gravitational field spontaneously breaks the CPT symmetry and splits the energy levels between particles and anti-particles. Baryon or Lepton number violating processes in proceeding at thermal equilibrium in such backgrounds gives rise to Baryon or Lepton number asymmetry.Comment: 62 pages, no figures. Invited review to appear in IJMP

Centrifugal force in Kerr geometry

We have obtained the correct expression for the centrifugal force acting on a particle at the equatorial circumference of a rotating body in the locally non-rotating frame of the Kerr geometry. Using this expression for the equilibrium of an element on the surface of a slowly rotating Maclaurin spheroid, we obtain the expression for the ellipticity (as discussed earlier by Abramowicz and Miller) and determine the radius at which the ellipticity is maximum.Comment: 6 pages, LateX macro

Large-scale processes in the upper layers of the Indian Ocean inferred from temperature climatology

Determination of amplitudes and phases for the annual and semi-annual cycle of the temperature in the Indian Ocean north of 20S from Levitus temperature climatology (1982) gives maximum amplitudes of the seasonal cycle at 100 m with the dominance of semi-annual cycle in the equatorial region and annual cycle elsewhere in the domain. The Bay of Bengal shows characteristics of the westward-propagating Rossby waves of annual period, while the Arabian Sea shows the dominance of Ekman pumping in the central region and westward-propagating features in the eastern region. Qualitative evidences obtained from the distribution of depth of 20°C isotherm and computed Ekman pumping velocities are consistent with the above inferences. From the time-longitude plot of the depth of the 20°C isotherm, the phase speed of westward propagating features from the west coast of India along 10.5N and 15.5N are found to be 7.8 cm s−1 and 5.2 cm s−1 respectively. This is consistent with the corresponding values computed and verified with theory for the Bay of Bengal (Prasanna Kumar and Unnikrishnan, 1995)

Evaluation of analgesic activity of levofloxacin in adult albino rats

Background: Levofloxacin is a fluorinated quinolone antimicrobial used in the treatment of various bacterial infections and was active against both gram positive and gram negative bacteria. Levofloxacin is an optically active isomer of ofloxacin. Apart from its antibacterial action, it also exhibit antinociceptive properties. This study was conducted with the aim to evaluate the analgesic activity of Levofloxacin in albino rat in comparison with aspirin.Methods: Thirty adult albino rats weighing 150-250 gm were obtained from central animal house. The animals were divided into five groups of six animals each. Group I served as control received normal feed and water. Group II served as standard received tablet aspirin 100 mg/kg (oral) and Group III, IV, V served as test T1, T2, T3 and received tablet levofloxacin 10 mg/kg, 20 mg/kg and 40 mg/kg (oral), respectively. The analgesic effect of levofloxacin was evaluated using Eddy’s hot plate and tail flick methods and compared with standard analgesic aspirin. The values obtained were expressed as mean±SD. Statistical analysis of difference between groups were carried out using one-way analysis of variance (ANOVA). Probability p<0.05 was taken as the level of statistical significance.Results: Levofloxacin at 40 mg/kg showed statistically (p<0.05) elevation in pain threshold and a higher antinociceptive activity in comparison to control and standard groups.Conclusions: In the present study, levofloxacin has showed promising results as an analgesic when compared to the control and standard groups. It may be a lead compound for identifying newer adjuvant analgesic agents

Interstitial cell network volume is reduced in the terminal bowel of ageing mice

Ageing is associated with impaired neuromuscular function of the terminal gastrointestinal (GI) tract, which can result in chronic constipation, faecal impaction and incontinence. Interstitial cells of cajal (ICC) play an important role in regulation of intestinal smooth muscle contraction. However, changes in ICC volume with age in the terminal GI tract (the anal canal including the anal sphincter region and rectum)have not been studied. Here, the distribution, morphology and network volume of ICC in the terminal GI tract of 3‐to 4‐month‐old and 26‐to 28‐month‐old C57BL/6mice were investigated. ICC were identified by immunofluorescence labelling of wholemount preparations with an antibody against c‐Kit. ICC network volume was measured by software‐based 3D volume rendering of confocal Z stacks. A significant reduction in ICC network volume per unit volume of muscle was measured in aged animals. No age‐associated change in ICC morphology was detected. The thickness of the circular muscle layer of the anal sphincter region and rectum increased with age, while that in the distal colon decreased. These results suggest that ageing is associated with a reduction in the network volume of ICC in the terminal GI tract, which may influence the normal function of these regions

Centrifugal Force and Ellipticity behaviour of a slowly rotating ultra compact object

Using the optical reference geometry approach, we have derived in the following, a general expression for the ellipticity of a slowly rotating fluid configuration using Newtonian force balance equation in the conformally projected absolute 3-space, in the realm of general relativity. Further with the help of Hartle-Thorne (H-T) metric for a slowly rotating compact object, we have evaluated the centrifugal force acting on a fluid element and also evaluated the ellipticity and found that the centrifugal reversal occurs at around $R/R_s \approx 1.45$, and the ellipticity maximum at around $R/R_s \approx 2.75$. The result has been compared with that of Chandrasekhar and Miller which was obtained in the full 4-spacetime formalism

Friction Stir Welding Of Magnesium Alloys - A Review

The modern technologies are gaining more and more importance in almost every field and Manufacturing industry not an exception. More and more research has been going on related to welding techniques [1]. Friction stir welding is one of the latest welding techniques that have found a major part in automotive sector. Magnesium alloy one of the major raw material used in these industries due to its light weight, good thermal conductivity, excellent specific strength and stiffness, exceptional dimensional stability, high damping capacity, and high recycle ability [2]. Magnesium alloys can be divided into cast magnesium alloys and wrought magnesium ones in terms of difference in processing [3]. Main commercial magnesium alloys include the AZ series (Mg-Al-Zl), AM series (Mg-Al-Mn), AE series (Mg-Al-RE), EZ series (Mg-RE-Zn), ZK series (Mg-Znmdash;Zr), and WE series (Mg-RE-Zr)[4]. It is thi property which entices automobile manufacturers to replace denser materials, not only steels, cast irons and copper base alloys but even aluminium alloys by magnesium based alloys. Statistically, more than 90% of the magnesium alloy structural components are produced by casting process, especially by various die-casting processes. .Magnesium has a density two-thirds that of aluminium and only slightly higher than of fibre-reinforced plastics and possesses excellent mechanical and physical properties. Compared to using alternative materials, using Mg alloys results in a 22% to 70% weight reduction. Recent developments in coating and alloying of Mg improved the creep and corrosion resistance properties of magnesium alloys for elevated temperatures and corrosive environments. The introduction of this paper gives a detailed review about Friction Stir Welding of Mg alloys. This review work may be a ready reference for subsequent researchers

Stability of accretion disk around rotating black holes: a pseudo-general-relativistic fluid dynamical study

We discuss the solution of accretion disk when the black hole is chosen to be rotating. We study, how the fluid properties get affected for different rotation parameters of the black hole. We know that no cosmic object is static in Universe. Here the effect of the rotation of the black hole to the space-time is considered following an earlier work of the author, where the pseudo-Newtonian potential was prescribed for the Kerr geometry. We show that, with the inclusion of rotation of the black hole, the valid disk parameter region dramatically changes and disk becomes unstable. Also we discuss about the possibility of shock in accretion disk around rotating black holes. When the black hole is chosen to be rotating, the sonic locations of the accretion disk get shifted or disappear, making the disk unstable. To bring it in the stable situation, the angular momentum of the accreting matter has to be reduced/enhanced (for co/counter-rotating disk) by means of some physical process.Comment: 24 Latex pages including 7 figures; Accepted for publication in Astrophysical Journa