Magnetotransport in the low carrier density ferromagnet EuB_6

We present a magnetotransport study of the low--carrier density ferromagnet EuB_6. This semimetallic compound, which undergoes two ferromagnetic transitions at T_l = 15.3 K and T_c = 12.5 K, exhibits close to T_l a colossal magnetoresistivity (CMR). We quantitatively compare our data to recent theoretical work, which however fails to explain our observations. We attribute this disagreement with theory to the unique type of magnetic polaron formation in EuB_6.Comment: Conference contribution MMM'99, San Jos

Visualisation of an entangled channel spin-1 system

Co-variance matrix formalism gives powerful entanglement criteria for continuous as well as finite dimensional systems. We use this formalism to study a mixed channel spin-1 system which is well known in nuclear reactions. A spin-j state can be visualized as being made up of 2j spinors which are represented by a constellation of 2j points on a Bloch sphere using Majorana construction. We extend this formalism to visualize an entangled mixed spin-1 system.Comment: 4 pages,4 figure

Environmental effects of SPS: The middle atmosphere

The heavy lift launch vehicle associated with the solar power satellite (SPS) would deposit in the upper atmosphere exhaust and reentry products which could modify the composition of the stratosphere, mesosphere, and lower ionosphere. In order to assess such effects, atmospheric model simulations were performed, especially considering a geographic zone centered at the launch and reentry latitudes

Instability of Rotationally Tuned Dipolar Bose-Einstein Condensates

The possibility of effectively inverting the sign of the dipole-dipole interaction, by fast rotation of the dipole polarization, is examined within a harmonically trapped dipolar Bose-Einstein condensate. Our analysis is based on the stationary states in the Thomas-Fermi limit, in the corotating frame, as well as direct numerical simulations in the Thomas-Fermi regime, explicitly accounting for the rotating polarization. The condensate is found to be inherently unstable due to the dynamical instability of collective modes. This ultimately prevents the realization of robust and long-lived rotationally tuned states. Our findings have major implications for experimentally accessing this regime.Comment: 9 pages with 5 figure

EFFECT OF LEAD ON MALE REPRODUCTION IN EXPERIMENTAL ANIMAL MODEL

Introduction: In early 1960's, there is a first evidence of the toxic effects ionizing radiation on elevated oxygen levels in aerobes and proposed that oxygen toxicity is due to free radical formation. An alteration between oxidants and antioxidants in favour of the oxidants, potentially leading to damage is termed 'oxidative stress'. Lead and cadmium do not have any detectable beneficial biological roles rather it produces detrimental effects on biochemical, physiological and behavioral dysfunctions. Even a little lead poisoning can cause serious health problems, and at very high levels, it can be fatal. Mainly it affects the heamopoeitc system, Liver, Kidney, Cardiovascular system and reproductive system. Methodology: Experimental rats, injected intraperitoneally with lead acetate for 15 days at the dosage of 50, 100 mg/kg/day body weight and compared to control rats injected with deionized distilled water instead. At the end of study testis were removed and right testis was used for testicular antioxidant Malandealdehyde (MDA) levels estimation by Thiobarbituric acid reactive substance assay and left testis was used for histopathological analysis. Unpaired t test and ANOVA was used for statistical analysis. Results : The MDA (nmole /gm tissue) levels in control, lead 50mg, lead 100mg groups were 12.16±0.4, 17.06±0.16 and 18.11±0.13. Histopathology examination Lumen showing decreased sperm count and maturation. Some of the lumens showing absence sperm maturation. Conclusion: Study on lead-exposed rat testis have shown that reduction of spermatogenesis formation and sperm maturation. Increased MDA levels indicate that it may be due to oxidative stress. The toxicity of lead was noted at level ≥50mg/kg. Key words: Lead; Lipid peroxidation; Male reproduction; Testicular histology

MELAS: A multigenerational impact of the MTTL1 A3243G MELAS mutation

Background: the maternally inherited MTTL1 A3243G mutation in the mitochondrial genome causes MelaS (Mitochondrial encephalopathy lactic acidosis with Stroke-like episodes), a condition that is multisystemic but affects primarily the nervous system. Significant intra-familial variation in phenotype and severity of disease is well recognized. Methods: retrospective and ongoing study of an extended family carrying the MTTL1 A3243G mutation with multiple symptomatic individuals. tissue heteroplasmy is reviewed based on the clinical presentations, imaging studies, laboratory findings in affected individuals and pathological material obtained at autopsy in two of the family members. Results: there were seven affected individuals out of thirteen members in this three generation family who each carried the MTTL1 A3243G mutation. the clinical presentations were varied with symptoms ranging from hearing loss, migraines, dementia, seizures, diabetes, visual manifestations, and stroke like episodes. three of the family members are deceased from MelaS or to complications related to MelaS. Conclusions: the results of the clinical, pathological and radiological findings in this family provide strong support to the current concepts of maternal inheritance, tissue heteroplasmy and molecular pathogenesis in MelaS. neurologists (both adult and paediatric) are the most likely to encounter patients with MelaS in their practice. genetic counselling is complex in view of maternal inheritance and heteroplasmy. newer therapeutic options such as arginine are being used for acute and preventative management of stroke like episodes. © 2014 Canadian Journal of neurologiCal sciences inc

Variation of electrical resistivity with high pressure in Ge-Te-Sn glasses: A composition dependent study

The variation of normalized electrical resistivity in the system of glasses Ge_{15}Te_{85-x}Sn_{x} with (1 ≤ x ≤ 5) has been studied as a function of high pressure for pressures up to 9.5 GPa. It is found that with the increase in pressure, the resistivity decreases initially and shows an abrupt fall at a particular pressure, indicating the phase transition from semiconductor to near metallic at these pressures, which lie in the range 1.5-2.5 GPa, and then continues being metallic up to 9.5 GPa. This transition pressure is seen to decrease with the increase in the percentage content of tin due to increasing metallicity of tin. The semiconductor to near metallic transition is exactly reversible and may have its origin in a reduction of the band gap due to high pressure

Stochastic Model and Computational Measures of Batch Process Queuing System with Hetero Multiservers

Multiprocessor system models at present are very important and widely used in modelling transaction processing systems, communication networks, mobile networks, and flexible machine shops with groups of machines. Heterogeneous processors system with one main server and several identical servers are studied. In this paper, reconfiguration and rebooting delays are considered to study the performance measures for both bounded and unbounded system. Numerical results are presented for various performability parameters