1,249 research outputs found

    Effect of breed and season on rabbit production under subtropical climate

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    [EN] The productive and reproductive performances of New Zealand White and Soviet Chinchilla breeds of rabbit were studied in the sub-tropical climate of Tripura, India. Data from 317 litters were collected and studied. The only signifi cant differences between the two breeds involved the number of services per conception and the inter-kindling interval which were signifi cantly (P<0.01) higher in the New Zealand White than in the Soviet Chinchilla breed. Neither breed nor gender had any signifi cant effect on individual body weight at weaning (42 d) or at day of slaughter (90 d). The season of kindling exerted a highly signifi cant (P<0.01) effect on the service period, kindling interval, and individual weight at weaning and at slaughtering age. Winter (November-March) was the most favourable season for kindling, whereas summer (April-June) proved to be the most unfavourable season in terms of both productive and reproductive effi ciency. The season of kindling did not affect age at the fi rst fertile service, age at fi rst kindling, the gestation period or the litter size at birth.Ghosh, S.; Das, A.; Bujarbaruah, K.; Das, A.; Dhiman, K.; Singh, N. (2010). Effect of breed and season on rabbit production under subtropical climate. World Rabbit Science. 16(1). doi:10.4995/wrs.2008.63816

    Phytochemical screening and evaluation of cytotoxic activity of Pandanus fascicularis L. (Fruits)

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    The present study was conducted to evaluate possible phytochemicals present, and cytoctoxic activity of extract of fruits of Pandanus fascicularis L. Phytochemical screening was carried out using the standard test methods of different chemical group. Evaluation of cytotoxic activity was done using the brine shrimp lethality bioassay. The aqueous, methanolic, ethanolic, ethyl acetate, pet ether and chloroform extracts show presence of maximum phytochemicals such as alkaloids, tannins, flavonoids, steroids, saponins, proteins, terpens, phenols, glycosides, carbohydrate in different fractions etc. During cytotoxicity test, the positive control groups showed nonlinear mortality rates at lower concentrations and linear rates at higher concentrations. The LC50 values of Chloroform extract was found 1.0636 µg/ml where the positive control vincristine sulphate showed LC50 at a concentration of 0.200µg/ml. Therefore, the plant extract possess potent cytotoxic effect

    Mass-losing accretion discs around supermassive black holes

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    We study the effects of outflow/wind on the gravitational stability of accretion discs around supermassive black holes using a set of analytical steady-state solutions. Mass-loss rate by the outflow from the disc is assumed to be a power-law of the radial distance and the amount of the energy and the angular momentum which are carried away by the wind are parameterized phenomenologically. We show that the mass of the first clumps at the self-gravitating radius linearly decreases with the total mass-loss rate of the outflow. Except for the case of small viscosity and high accretion rate, generally, the self-gravitating radius increases as the amount of mass-loss by the outflow increases. Our solutions show that as more angular momentum is lost by the outflow, then reduction to the mass of the first clumps is more significant.Comment: Accepted for publication in Astrophysics & Space Scienc

    High-Temperature Hall Effect in Ga(1-x)Mn(x)As

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    The temperature dependence of the Hall coefficient of a series of ferromagnetic Ga(1-x)Mn(x)As samples is measured in the temperature range 80K < T < 500K. We model the Hall coefficient assuming a magnetic susceptibility given by the Curie-Weiss law, a spontaneous Hall coefficient proportional to rho_xx^2(T), and including a constant diamagnetic contribution in the susceptibility. For all low resistivity samples this model provides excellent fits to the measured data up to T=380K and allows extraction of the hole concentration (p). The calculated p are compared to alternative methods of determining hole densities in these materials: pulsed high magnetic field (up to 55 Tesla) technique at low temperatures (less than the Curie temperature), and electrochemical capacitance- voltage profiling. We find that the Anomalous Hall Effect (AHE) contribution to rho_xy is substantial even well above the Curie temperature. Measurements of the Hall effect in this temperature regime can be used as a testing ground for theoretical descriptions of transport in these materials. We find that our data are consistent with recently published theories of the AHE, but they are inconsistent with theoretical models previously used to describe the AHE in conventional magnetic materials.Comment: 6 pages, 5 figures, 1 table. Accepted to Phys.Rev.

    A modular focal plane detector system for the heavy ion reaction analyzer at NSC, New Delhi

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    A detector system has been developed for the focal plane of the HIRA. It consists of two independent detectors, a low-pressure multiwire proportional counter (LP-MWPC) followed by a split-anode ionization detector. Details of the design and test results are presented. Using slow preamplifiers, the position resolution is ≥1 mm and the time resolution is estimated to be 1.5 ns for the LP-MWPC. The ionization detector gives 2.4% energy resolution for 150 MeV 28Si scattered off a gold target and the ΔZ/Z obtained for 28Si+27Al is 1/42 for Z=14. Some results for fusion and transfer studies for the 48Ti+58Ni and 28Si+68Zn systems, respectively, at energies around the Coulomb barrier, are presented to highlight the performance of the detector system

    Diffusion of particles moving with constant speed

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    The propagation of light in a scattering medium is described as the motion of a special kind of a Brownian particle on which the fluctuating forces act only perpendicular to its velocity. This enforces strictly and dynamically the constraint of constant speed of the photon in the medium. A Fokker-Planck equation is derived for the probability distribution in the phase space assuming the transverse fluctuating force to be a white noise. Analytic expressions for the moments of the displacement along with an approximate expression for the marginal probability distribution function P(x,t)P(x,t) are obtained. Exact numerical solutions for the phase space probability distribution for various geometries are presented. The results show that the velocity distribution randomizes in a time of about eight times the mean free time (8t8t^*) only after which the diffusion approximation becomes valid. This factor of eight is a well known experimental fact. A persistence exponent of 0.435±0.0050.435 \pm 0.005 is calculated for this process in two dimensions by studying the survival probability of the particle in a semi-infinite medium. The case of a stochastic amplifying medium is also discussed.Comment: 9 pages, 9 figures(Submitted to Phys. Rev. E

    Transfer measurements for the Ti plus Ni systems at near barrier energies

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    Large enhancements have been observed in the sub-barrier fusion cross sections for Ti + Ni systems in our previous studies. Coupled channel calculations incorporating couplings to 2(+) and 3(-) states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer were carried out for Ti-46,Ti-48 + Ni-64 systems. The present paper gives the results of these studies

    High resolution infrared absorption spectra, crystal field, and relaxation processes in CsCdBr_3:Pr^3+

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    High resolution low-temperature absorption spectra of 0.2% Pr^3+ doped CsCdBr_3 were measured in the spectral region 2000--7000 cm-1. Positions and widths of the crystal field levels within the 3H5, 3H4, 3F2, and 3F3 multiplets of the Pr^3+ main center have been determined. Hyperfine structure of several spectral lines has been found. Crystal field calculations were carried out in the framework of the semiphenomenological exchange charge model (ECM). Parameters of the ECM were determined by fitting to the measured total splittings of the 3H4 and 3H6 multiplets and to the observed in this work hyperfine splittings of the crystal field levels. One- and two-phonon relaxation rates were calculated using the phonon Green's functions of the perfect (CsCdBr_3) and locally perturbed (impurity dimer centers in CsCdBr_3:Pr^3+) crystal lattice. Comparison with the measured linewidths confirmed an essential redistribution of the phonon density of states in CsCdBr_3 crystals doped with rare-earth ions.Comment: 16 pages, 5 tables, 3 figure

    Localization dynamics in a binary two-dimensional cellular automaton: the Diffusion Rule

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    We study a two-dimensional cellular automaton (CA), called Diffusion Rule (DR), which exhibits diffusion-like dynamics of propagating patterns. In computational experiments we discover a wide range of mobile and stationary localizations (gliders, oscillators, glider guns, puffer trains, etc), analyze spatio-temporal dynamics of collisions between localizations, and discuss possible applications in unconventional computing.Comment: Accepted to Journal of Cellular Automat

    Chiral and Gluon Condensates at Finite Temperature

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    We investigate the thermal behaviour of gluon and chiral condensates within an effective Lagrangian of pseudoscalar mesons coupled to a scalar glueball. This Lagrangian mimics the scale and chiral symmetries of QCD. (Submitted to Z. Phys. C)Comment: 20 pages + 7 figures (uuencoded compressed postscript files), University of Regensburg preprint TPR-94-1
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