Self similar Barkhausen noise in magnetic domain wall motion

A model for domain wall motion in ferromagnets is analyzed. Long-range magnetic dipolar interactions are shown to give rise to self-similar dynamics when the external magnetic field is increased adiabatically. The power spectrum of the resultant Barkhausen noise is of the form $1/\omega^\alpha$, where $\alpha\approx 1.5$ can be estimated from the critical exponents for interface depinning in random media.Comment: 7 pages, RevTex. To appear in Phys. Rev. Let

P53 tumour-suppressor gene mutations are mainly localised on exon 7 in human primary and metastatic prostate cancer.

Mutations in the p53 tumour-suppressor gene are among the most common genetic alterations in human cancers. In the present study we analysed the mutations in the p53 tumor-suppressor gene in 25 primary and 20 metastatic human prostate cancer specimens. DNA extracted from the paraffin-embedded sections was amplified by hot-start polymerase chain reaction, and p53 gene mutations in the conserved mid-region (exons 4-9) were examined using single-strand conformation polymorphism (SSCP) analysis and immunohistochemistry. In the present study, we used a novel hot-start PCR-SSCP technique using DNA Taq polymerase antibody, which eliminates primer-dimers and non-specific products. Because of this new technique, the results of PCR-SSCP showed very high resolution. Polymerase chain reaction products were sequenced directly for point mutations for the p53 gene. Mutations were found in 2 out of 25 primary prostate cancers (8%) and 4 out of 20 metastatic cancers (20%). Mutations were observed exclusively in exon 7 and not in exons 4, 5, 6, 8 or 9. Nuclear accumulation of p53 protein, determined by immunohistochemistry, correlated with the degree of metastasis in prostatic cancer

Probing the matter term at long baseline experiments

We consider (\nu_\mu --> \nu_e) oscillations in long baseline experiments within a three flavor framework. A non-zero measurement of this oscillation probability implies that the (13) mixing angle `phi' is non-zero. We consider the effect of neutrino propagation through the matter of earth's crust and show that, given the constraints from solar neutrino and CHOOZ data, matter effects enhance the mixing for neutrinos rather than for anti-neutrinos. We need data from two different experiments with different baseline lengths (such as K2K and MINOS) to distinguish matter effects unambiguously.Comment: 9 pages including three figure

Linkage Between Effective Implementation of IS Strategy and IS Performance: Lessons from Indian Organizations

The overall outcome of IS planning efforts is determined by how effectively the planned strategies are implemented in order to realize the envisaged strategic benefits. This empirical work on IS plan implementation relates the effective implementation of IS plan with IS performance in the Indian context. Based on three case studies from diverse industry segments, we discuss the five important parameters of IS plan implementation- top management commitment, implementation responsibility, IS plan characteristics, user involvement, role of IS function that determine the implementation effectiveness and eventually the IS performance. Based on the analysis, we present a set of key learnings for developing countries, along with implications for future research

Solar Neutrinos and the Eclipse Effect

The solar neutrino counting rate in a real time detector like Super--Kamiokanda, SNO, or Borexino is enhanced due to neutrino oscillations in the Moon during a partial or total solar eclipse. The enhancement is calculated as a function of the neutrino parameters in the case of three flavor mixing. This enhancement, if seen, can further help to determine the neutrino parameters.Comment: 24 Pages Revtex, 8 figures as one ps file. To appear in Phys. Rev. D; Some typos corrected and a reference adde

Radio-wave propagation through a medium containing electron-density fluctuations described by an anisotropic Goldreich-Sridhar spectrum

We study the propagation of radio waves through a medium possessing density fluctuations that are elongated along the ambient magnetic field and described by an anisotropic Goldreich-Sridhar power spectrum. We derive general formulas for the wave phase structure function, visibility, angular broadening, diffraction-pattern length scales, and scintillation time scale for arbitrary distributions of turbulence along the line of sight, and specialize these formulas to idealized cases.Comment: 25 pages, 3 figures, submitted to Ap

Hybrid Thermal-Nonthermal Synchrotron Emission from Hot Accretion Flows

We investigate the effect of a hybrid electron population, consisting of both thermal and non-thermal particles, on the synchrotron spectrum, image size, and image shape of a hot accretion flow onto a supermassive black hole. We find two universal features in the emitted synchrotron spectrum: (i) a prominent shoulder at low (< 10^11 Hz) frequencies that is weakly dependent on the shape of the electron energy distribution, and (ii) an extended tail of emission at high (> 10^13 Hz) frequencies whose spectral slope depends on the slope of the power-law energy distribution of the electrons. In the low-frequency shoulder, the luminosity can be up to two orders of magnitude greater than with a purely thermal plasma even if only a small fraction (< 1%) of the steady-state electron energy is in the non-thermal electrons. We apply the hybrid model to the Galactic center source, Sgr A*. The observed radio and IR spectra imply that at most 1% of the steady-state electron energy is present in a power-law tail in this source. This corresponds to no more than 10% of the electron energy injected into the non-thermal electrons and hence 90% into the thermal electrons. We show that such a hybrid distribution can be sustained in the flow because thermalization via Coulomb collisions and synchrotron self-absorption are both inefficient. The presence of non-thermal electrons enlarges the size of the radio image at low frequencies and alters the frequency dependence of the brightness temperature. A purely thermal electron distributions produces a sharp-edged image while a hybrid distribution causes strong limb brightening. These effects can be seen up to frequencies ~10^11 Hz and are accessible to radio interferometers.Comment: 33 pages with figures, to appear in the Astrophysical Journa

The antiviral drug ribavirin reversibly affects the reproductive parameters in the male Wistar rat

The present study was planned to evaluate the toxic effects of ribavirin on the reproductive parameters in the male Wistar rat. Rats (11&#8211;13 weeks old) were treated with 5 injections (i.p.) of 20, 100 or 200 mg/kg/day ribavirin at intervals of 24 h. The testes were processed for histopathological analysis on days 14, 35, 70 and 105 after the last exposure. The parameters studied were body weight, the weights of the testis, epididymis, seminal vesicle and prostate, seminiferous tubular diameter (STD), epithelial height (SE), epithelial sloughing, incidence of stage XIV tubules, sperm abnormality and total serum level of testosterone. Data were analysed by ANOVA and the Bonferroni post hoc test for significances between different groups. There was a decrease in body weight and organ weights, excluding those of the testis and epididymis, against control at higher dose-levels. Ribavirin induced the formation of vacuoles, gaps and sloughing of the seminiferous epithelium. The STD, SE and the incidences of stage XIV tubules decreased on days 14 and 35. Ribavirin also induced the formation of sperm with microcephaly and cephalocaudal junction defects, with or without fibrils jetting out. All these morphological defects recovered to control limit by day 105. The serum level of testosterone was decreased at all dose-levels and time points, although recovery had started by day 105. In conclusion, ribavirin is gonadotoxic in male rats but the effects are reversible after a period of 105 days. However, the endocrine-disrupting properties of ribavirin persist beyond this period

Phenomenology of Neutrino Oscillations

The phenomenology of solar, atmospheric, supernova and laboratory neutrino oscillations is described. Analytical formulae for matter effects are reviewed. The results from oscillations are confronted with neutrinoless double beta decay.Comment: 11 pages, 2 figures, latex, Plenary talk given at Workshop in High Energy Particle Physics-6, Chennai, Indi