Spinning Test Particle in Kalb-Ramond background

In this work we explore the geodesic deviations of spinning test particles in a string inspired Einstein-Kalb Ramond background. Such a background is known to be equivalent to a spacetime geometry with torsion. We have shown here that the antisymmetric Kalb-Ramond field has significant effect on the geodesic deviation of a spinning test particle. A search for an observational evidence of such an effect in astrophysical experiments may lead to a better undestanding of the geometry of the background spacetime.Comment: 14 pages, Latex, 5 figure

Bulk Kalb-Ramond field in Randall Sundrum scenario

We have considered the most general gauge invariant five-dimensional action of a second rank antisymmetric Kalb-Ramond tensor gauge theory, including a topological term of the form $\epsilon^{ABLMN}B_{AB}H_{LMN}$ in a Randall-Sundrum scenario. Such a tensor field $B_{AB}$ (whose rank-3 field strength tensor is $H_{LMN}$), which appears in the massless sector of a heterotic string theory, is assumed to coexist with the gravity in the bulk. The third rank field strength corresponding to the Kalb-Ramond field has a well-known geometric interpretation as the spacetime torsion. The only non-trivial classical solutions corresponding to the effective four-dimensional action are found to be self-dual or anti-selfdual Kalb-Ramond fields. This ensures that the four-dimensional effective action on the brane is parity-conserving. The massive modes for both cases, lying in the TeV range, are related to the fundamental parameters of the theory. These modes can be within the kinematic reach of forthcoming TeV scale experiments. However, the couplings of the massless as well as massive Kalb-Ramond modes with matter on the visible brane are found to be suppressed vis-a-vis that of the graviton by the warp factor, whence the conclusion is that both the massless and the massive torsion modes appear much weaker than curvature to an observer on the visible brane.Comment: 15 Pages,2 figures,Late

Synthetic Polymer Based Coating of Fodder Cowpea Seeds Enhances Germination and Vigour

In Indian arid and semi-arid conditions, comparatively less fertile lands are allotted to forage crops. In addition, erratic weather condition makes the situation more complex where proper seedling emergence and establishment of pastures with economic use of input remains a big question. Our view is that crop seedling production from seed sown into arid or semiarid environments could be significantly enhanced by the use of simple seed coating technologies. Such approaches would make use of newly synthesised seed coat-applied polymers that could be used to hold the desired supplements like powerful germination enhancement chemicals and plant protectants with seed to support both germination and seedling establishment under the crucial stages. This approach would be expected to increase the rate and speed of germination, thereby bringing the uniformity in plant population even under stressful (drought) growing conditions. On the other hand, cowpea seed are highly susceptible to insect pest during storage in addition to seed borne diseases. Hence, coating of seed was envisaged in order to protect the seeds from pest attack and boost initial seedling vigour

Constraining the Randall-Sundrum modulus in the light of recent PVLAS data

Recent PVLAS data put stringent constraints on the measurement of birefringence and dichroism of electromagnetic waves travelling in a constant and homogeneous magnetic field. There have been theoretical predictions in favour of such phenomena when appropriate axion-electromagnetic coupling is assumed. Origin of such a coupling can be traced in a low energy string action from the requirement of quantum consistency. The resulting couplings in such models are an artifact of the compactification of the extra dimensions present inevitably in a string scenario. The moduli parameters which encode the compact manifold therefore play a crucial role in determining the axion-photon coupling. In this work we examine the possible bounds on the value of compact modulus that emerge from the experimental limits on the coupling obtained from the PVLAS data. In particular we focus into the Randall-Sundrum (RS) type of warped geometry model whose modulus parameter is already restricted from the requirement of the resolution of gauge hierarchy problem in connection with the mass of the Higgs. We explore the bound on the modulus for a wide range of the axion mass for both the birefringence and the dichroism data in PVLAS. We show that the proposed value of the modulus in the RS scenario can only be accommodated for axion mass \gsim 0.3 eV.Comment: 26 pages, 1 figure, LaTex; added references, typos corrected. Minor changes in the text, a comment added in the Conclusio

Charged black holes in generalized dilaton-axion gravity

We study generic Einstein-Maxwell-Kalb-Ramond-dilaton actions, and derive conditions under which they give rise to static, spherically symmetric black hole solutions. We obtain new asymptotically flat and non-flat black hole solutions which are in general electrically and magnetically charged. They have positive definite and finite quasi-local masses. Existing non-rotating black hole solutions (including those appearing in low energy string theory) are recovered in special limits.Comment: Replaced with revised version, 33 pages, No figure

Anthesis Dynamics, Pollen Availability and Enhancement of Seed to Ovule Ratio in \u3cem\u3eChrysopogon fulvus\u3c/em\u3e

Under the present scenario of severe green fodder shortage (64%) in India, grassland offers an opportunity to enhance fodder availability. To revitalize the existing denuded grasslands, seed is the best propagating material. Availability of quality seed in forage grasses is less than 20% of actual requirement/ demand. Hence, there is a need to enhance the production and productivity of grass seeds. Even the available grass seeds have very low germination percentage, which is mainly due to the absence of a caryopsis inside the fluffy seed material. Chrysopogon fulvus, commonly known as Guria grass or red false beard grass, is a tufted perennial tropical grassland species, with good palatability and green fodder potential of \u3e20 t/ha. With its ability to grow under annual rainfall of 300-1200 mm it is well suited for the rainfed situation of Indian grasslands. As per Indian minimum seed certification standards (IMSCS), the germination percentage of C. fulvus is only 15%. The low germination coincides with the low seed setting (14-18%) as recorded in bulk harvested sample by Bahukhandi et al. (2011). Enhancement of seed to ovule ratio not only increases germination percent but enhances productivity per se. With this background, the present study was undertaken to understand the reproductive morphology, pollen availability and effect of exogenous application of chemicals for enhancement of seed to ovule ratio in C. fulvus

Design and Simulation of Extended Interaction Cavities for a Ka band Multi beam Klystron

This article reports about the design approach, electromagnetic simulation and analysis results of high-frequency ladder-type input, output, and intermediate RF cavaties for Ka-band multi-beam extended interaction klystron. Several parameters of the cavity, such as quality factor, shunt impedance, etc., have been investigated by the assistance of electromagnetic software CST microwave studio

Efficacy of Different Herbicides on Weed Flora of Berseem (\u3cem\u3eTrifolium alexandrium L.\u3c/em\u3e)

Berseem is one of the prominent winter legume fodder crops. It has 20-24% crude protein and 70% digestible dry matter. Common weeds found in berseem are Cichorium intybus, Cornopus didimus, Spergula arvensis, Chenopodium album, Rumex dentatus and some grass family weeds. Weeds compete with main crop for essential plant nutrients, light, moisture and space. They not only deteriorate fodder quality but also decrease fodder and seed yield. Weed infestation reduces normally 25-35% green fodder and seed yield. It is the major challenge to control the berseem weeds for enhancement of productivity and quality of fodder and seed yield. Hence the present investigation is undertaken to study the efficacy of some herbicides for berseem weed management

Large magnetoelectric coupling in nanoscale BiFeO3_3 from direct electrical measurements

We report the results of direct measurement of remanent hysteresis loops on nanochains of BiFeO$_3$ at room temperature under zero and $\sim$20 kOe magnetic field. We noticed a suppression of remanent polarization by nearly $\sim$40\% under the magnetic field. The powder neutron diffraction data reveal significant ion displacements under a magnetic field which seems to be the origin of the suppression of polarization. The isolated nanoparticles, comprising the chains, exhibit evolution of ferroelectric domains under dc electric field and complete 180$^o$ switching in switching-spectroscopy piezoresponse force microscopy. They also exhibit stronger ferromagnetism with nearly an order of magnitude higher saturation magnetization than that of the bulk sample. These results show that the nanoscale BiFeO$_3$ exhibits coexistence of ferroelectric and ferromagnetic order and a strong magnetoelectric multiferroic coupling at room temperature comparable to what some of the type-II multiferroics show at a very low temperature.Comment: 7 pages with 5 figures, published in Phys. Rev.

Evaluation of Hepatoprotective Effect of Leaves of Cassia sophera Linn.

In the present study, the hepatoprotective activity of ethanolic extracts of Cassia sophera Linn. leaves was evaluated against carbon-tetrachloride- (CCl4-) induced hepatic damage in rats. The extracts at doses of 200 and 400 mg/kg were administered orally once daily. The hepatoprotection was assessed in terms of reduction in histological damage, changes in serum enzymes, serum glutamate oxaloacetate transaminase (AST), serum glutamate pyruvate transaminase (ALT), serum alkaline phosphatase (ALP), total bilirubin, and total protein levels. The substantially elevated serum enzymatic levels of AST, ALT, ALP, and total bilirubin were restored towards the normalization significantly by the extracts. The decreased serum total protein level was significantly normalized. Silymarin was used as standard reference and exhibited significant hepatoprotective activity against carbon tetrachloride-induced hepatotoxicity in rats. The biochemical observations were supplemented with histopathological examination of rat liver sections. The results of this study strongly indicate that Cassia sophera leaves have potent hepatoprotective action against carbon tetrachloride-induced hepatic damage in rats. This study suggests that possible activity may be due to the presence of flavonoids in the extracts