Rock Magnetic properties of Proterozoic mafic dykes from the Southern margin of Cuddapah Basin

Seventeen basic dykes of Proterozoic age intruding the Archaean basement from the Southern margin of the Cuddapah Basin were studied from five sites for their magnetic characters. NRM intensity (Jn) of the dykes range between 1793 and 57×10−3 Am−1 while magnetic susceptibility (χ) ranges from 31 to 303×10−6 CGS units. Koenigsberger's ratio (Qn) varies from 1 to 55 for most of the specimens. All the above parameters are indicative of retaining the original magnetization in most of the dykes sampled. Based on the above mentioned rock magnetic properties along with hysterisis studies and low temperature (−196°C) magnetic studies, it is inferred that the main magnetic carrier in these dykes is magnetite in multi domain and mixed domain states. Dykes from Tirupati area seems to be magnetically altered

Local canted spin behaviour in Co_1.4-xZn_xGe_0.4Fe_1.2O₄ spinels: a macroscopic, mesoscopic and microscopic study

DC magnetization, neutron depolarization and neutron diffraction (with both polarized and unpolarized neutrons) measurements have been reported for the Co1.4-xZnxGe0.4Fe1.2O4 spinels with x=0.5, 0.6 and 0.7. Neutron depolarization and neutron diffraction measurements confirm the presence of a long range ferrimagnetic ordering of the local canted spins in these ferrite samples. The observed features of low field magnetization have been explained under the framework of thermally activated domain wall movement of ferrimagnetic arrangement of local canted spins. An important role of magnetic anisotropy (due to the presence of Co2+ ions) in establishing the magnetic ordering and domain kinetics in these ferrites has been observed

Early Proterozoic Melt Generation Processes beneath the Intra-cratonic Cuddapah Basin, Southern India

Early Proterozoic tholeiitic lavas and sills were emplaced during the initial phase of extension of the intra-cratonic Cuddapah Basin, Southern India. 40Ar-39Ar laser-fusion determinations on phlogopite mica, from the Tadpatri Fm mafic-ultramafic sill complex, constrain the age of the initial phase of extension and volcanism in the basin at 1·9Ga. Despite their Early Proterozoic age, the igneous rocks are unmetamorphosed, undeformed and remarkably fresh. They exhibit a wide range in MgO contents (4-28wt%) and have undergone varying degrees of accumulation or crystal fractionation. Variable La/Nb ratios (1·2-3·7) and εNd values (1 to -10) suggest that some, but not all, of the mafic rocks have been affected by crustal contamination. This appears to have taken place in magma chambers at ~9kbar, i.e. the base of the continental crust. Forward modelling of major and trace elements (Fe and Nd) and inverse modelling of rare earth elements suggest that the primary Cuddapah melts were generated by ~10-15% partial melting of a lherzolite mantle source. This corresponds to a mantle potential temperature of ~1500°C. The thickness of the mechanical boundary layer predicted by the geochemical modelling is 70km with a minimum initial lithospheric thickness of 120km. This corresponds to a stretching factor of 1·6-1·8. Richter's (1988) secular cooling model for the Earth predicts that, at 1·9Ga, the ambient mantle had a potential temperature of ~1500°C (i.e. ~200°C hotter than Phanerozoic mantle). If the cooling model is correct then Proterozoic lithospheric stretching and mantle melting beneath the intra-cratonic Cuddapah Basin could have been caused by passive rather than active rifting

Evaluation of anti-tumor activity of ethanolic extract of Glycyrrhiza glabra against Ehrlich ascites carcinoma in swiss albino mice

Background: Cancer is one of the most life threatening diseases which is in need of newer drug development. The use of plant products with potent antioxidant and cytotoxic activity is upcoming Studies reveal that herbal product have increased efficacy as well as decreased side effects, with this in mind the present study was undertaken to assess the antitumor activity of extracts of Glycyrrhiza glabra (GG) against ehrlich ascites carcinoma in swiss albino mice.Methods: The extracts of roots of GG was collected and acute toxicity study was done following which the antitumor effect of extracts of GG was assessed by change in the body weight, mean survival time (MST), and percentage increased life span (% ILS). MST of each group containing six mice was monitored by recording the mortality daily for 6 weeks and % ILS was calculated. The hematological parameters and biochemical assays were also measured.Results: Extracts of GG showed a significant reduction in % increase in tumor induced body weight of the mice. The % increase in life span was also significant in the higher dose of GG (500 mg/kg). The combination of GG with standard drug cisplatin had better efficacy in terms of % ILS, hematological and biochemical parameters. The results obtained were statistically significant.Conclusions: The antitumor activity studies measuring the viability of cancer cells when exposed to the ethanolic extract of Glycyrrhiza glabra showed a potent cell-killing effect, indicating the presence of anti-cancer principles in the preparation

Decay of Samarium-153

Radiations emitted in the decay of Samarium-153 have been studied in the Siegbahn-Slatis beta-ray spectrometer. Using the internal conversion electron spectrum and the photo-electron spectrum with tin as radiator, the internal conversion coefficient αk has been determined for 102 Kev. and 70 Kev.gamma-rays. The relative intensities of the three beta-ray branches have been determined. A weak gamma-ray of energy 83 Kev. has been found and can be interpreted as a transition to the ground state from the first rotational level in Europium-153. The multipole order and character of the 102 Kev. transition is discussed

Characterizations of the diurnal shapes of OI 630.0 nm dayglow intensity variations: inferences

International audienceMeasurements of OI 630.0 nm thermospheric dayglow emission by means of the Dayglow Photometer (DGP) at Mt. Abu (24.6° N, 73.7° E, dip lat 19.09° N), a station under the crest of Equatorial Ionization Anomaly (EIA), reveal day-to-day changes in the shapes of the diurnal profiles of dayglow intensity variations. These shapes have been characterized using the magnetometer data from equatorial and low-latitude stations. Substantial changes have been noticed in the shapes of the dayglow intensity variations between 10:00?15:00 IST (Indian Standard Time) during the days when normal and counter electrojet events are present over the equator. It is found that the width (the time span corresponding to 0.8 times the maximum dayglow intensity) of the diurnal profile has a linear relationship with the integrated electrojet strength. Occasional deviation from this linear relationship is attributed to the presence of substantial mean meridional wind