Seismic Effects in F2 Region Related to Electron Temperature

The effect of earthquakes in the ionospheric F2 range was studied using the Indian satellite SROSS-C2 data on the cosmic electron temperature around the Indian sector in the ranges 0-34 ° N and 40-100 ° E for the period 1995-1997. Five episodes of earthquakes were analyzed and the observed anomalies at an average electron temperature were 29 to 10% higher than in the preceding days, and 16 to 4% higher than on days after the earthquake, and a latitudinal variation of this temperature. It is shown that the increase in this temperature was the maximum on the day preceding the earthquake, and for several hours before and after it. The anomalies observed around (in the ± 2-degree latitude range) were the epicenter of the earthquake. They were probably observed due to electromagnetic radiation during the earthquake activity. The period from 1995 to 1997 for this study was taken as a period of quiet geomagnetic conditions

FORMULATION AND IN-VITRO EVALUATION OF EFAVIRENZ LIQUISOLID COMPACTS

Objective: The present research is aimed to enhance the dissolution rate of Efavirenz using liquisolid compact technology.Methods: About 16 different formulations were developed using factorial design with carriers (Neusilin and Fugicalin), binder (PVP K-30) and vehicle (polyethylene glycol 300) as independent variables and aerosil 200 is used as coating material. The In-vitro drug release from the LSC has used a dependent variable. The empirical method by Spireas and Bolton was applied to calculate the amounts of carrier and coating materials and obtained the improved flow characteristics and hardness by changing the proportion of carrier and coating materials.Results: A 23 factorial design is used and developed LSC using Neusilin (LSC-N1 to LSC-N8) and Fugicalin (LSC-F1 to LSC-F8). The physicochemical evaluation of all formulations exhibited well within the specification limits with respect to weight variation, hardness, friability and content uniformity. The In-vitro drug release from these LSC was evaluated in 0.1 N HCl and the optimized formulation (LSC-N8) was compared with pure drug (capsule) and physical mixture (tablet). The release studies proved that the liquisolid tablets results in higher release profile than pure drug and physical mixture due to increase in surface and wetting properties of the drug.Conclusion: LSC technique confirmed the enhanced dissolution rate of Efavirenz, which in turn helps in improving bioavailability.Â

Effective chiral-spin Hamiltonian for odd-numbered coupled Heisenberg chains

An $L \times \infty$ system of odd number of coupled Heisenberg spin chains is studied using a degenerate perturbation theory, where $L$ is the number of coupled chains. An effective chain Hamiltonian is derived explicitly in terms of two spin half degrees of freedom of a closed chain of $L$ sites, valid in the regime the inter-chain coupling is stronger than the intra-chain coupling. The spin gap has been calculated numerically using the effective Hamiltonian for $L=3,5,7,9$ for a finite chain up to ten sites. It is suggested that the ground state of the effective Hamiltonian is correlated, by examining variational states for the effective chiral-spin chain Hamiltonian.Comment: 9 Pages, Latex, report ICTP-94-28

Improving Scheelite Recovery from Gold Tailings

Tungsten occupies a very important place amongst the strategic metals. However, resources available in India are scarce and lean in grade. Various physical methods of beneficiation have been tried to beneficiate such, low grade ores, but these have not been generally efficient in terms of high recoveries and concentrate grades. Tungsten minerals, wolframite and scheelite being friable, tend to slime during size reduction stages. Because of this, high loss in slimes occurs during conventional gravity opera-tions. Flotation techniques too have not been very succe-ssful though some excellent results have been reported by Mercade (1) on direct flotation of scheelite from low grade ores. Recently special gravity concentration equi-pment such as Bartles Mozley Separator (MIS)and Cross Belt Concentrator (CBC) have been used in separation of a wide variety of fine heavy minerals including scheelite (2, 3, 4, 5). To obtain a high grade concentrate, a combination of gravity and flotation and/or magnetic separation method is generally employed

Components of Resistance to Puccinia arachidis in Peanuts

Thirty peanut genotypes were inoculated with uredospores of the rust fungus Puccinia arachidis in a replicated glasshouse trial, and components of disease resistance—incubation period, infection frequency, pustule diameter, percent ruptured pustules, and percent leaf area damaged—were studied for a single cycle of infection. All components studied were significantly correlated with one another and with mean field rust scores taken over several seasons. Incubation period was negatively correlated with the other components, which were positively correlated with one another. Resistant and susceptible genotypes were readily separated on the basis of the resistance components measured in the glasshouse trial, but classification of moderately resistant genotypes was less effective by this method than by use of field scores. A glasshouse screening method could be useful in areas where rust epidemics do not occur or are irregular in occurrence or where other foliar diseases interfere with field screening. The measurement of epidemiologically significant characters will allow the identification of rate-limiting resistance, which is likely to be more stable than immunity

Screening methods and further sources of resistance to peanut rust

creened for resistance to rust at ICRISAT, India. Preliminary field screening was done during the 1977 rainy season when a natural epidemic of rust was in progress. The cultivars or lines which were rated between 2 and 5 on a Spoint scale during this screening were further tested during the 1977/78 dry season employing an infector row system of susceptible cultivars and spreader plants systematically interplanted with the test material. High relative humidity was maintained in the field by operating an overhead sprinkler irrigation system. Percentage leaf area damaged on the test material was estimated at 10 day intervals from approximately 90 days after their emergence until harvest. Each entry was also assessed on a scale proposed by Mazzani and Hinojosa. Two land races, NC.Ac. 17090 and EC. 76446 (292) were more resistant than either PI. 259747 or PI. 298115 which were reported resistant by other workers. In addition, NC.Ac. 17030, NC.Ac. 17132, NC.Ac. 17129, NC. Ac. 17135 and NC.Ac. 17124 were moderately resistant. Four cultivars or lines with different levels of resistance in the field were tested in the greenhouse at three different stages in development. The results indicated that resistance increased as the plants aged

Resistance to Leaf Spot Caused by Cercosporidium personatum in Wild Arachis Species

When 96 accessions of wild A. spp. were evaluated against C. personatum [Mycosphaerella berkeleyi], lesions were formed on leaflets of all accessions but were small and nonsporulating on all those of sections Erectioides, Triseminalae, Extranervosae, Rhizomatosae, and Caulorhizae. Spp. in section Arachis had lesions 0.16-1 mm diam.; 15 accessions had no sporulating lesions, while in the others, sporulation was slight to extensive. Frequency of infection (number of lesions/cm² leaf area) and percentage defoliation varied greatly within each section and species

Hidden long range order in Heisenberg Kagome antiferromagnets

We give a physical picture of the low-energy sector of the spin 1/2 Heisenberg Kagome antiferromagnet (KAF). It is shown that Kagome lattice can be presented as a set of stars which are arranged in a triangular lattice and contain 12 spins. Each of these stars has two degenerate singlet ground states which can be considered in terms of pseudospin. As a result of interaction between stars we get Hamiltonian of the Ising ferromagnet in magnetic field. So in contrast to the common view there is a long range order in KAF consisting of definite singlet states of the stars.Comment: 4 pages, 3 figures, submitted to Physical Review Letter