Finding the optimum activation energy in DNA breathing dynamics: A Simulated Annealing approach

We demonstrate how the stochastic global optimization scheme of Simulated Annealing can be used to evaluate optimum parameters in the problem of DNA breathing dynamics. The breathing dynamics is followed in accordance with the stochastic Gillespie scheme with the denaturation zones in double stranded DNA studied as a single molecule time series. Simulated Annealing is used to find the optimum value of the activation energy for which the equilibrium bubble size distribution matches with a given value. It is demonstrated that the method overcomes even large noise in the input surrogate data.Comment: 9 pages, 4 figures, iop article package include

Optimal operating conditions and characteristics of acetone/CaF_2 detector for inverse photoemission spectroscopy

Performance and characteristics of a band-pass photon detector using acetone gas and CaF_2 window (acetone/CaF_2) have been studied and compared with an ethanol/MgF_2 detector. The optimal operating conditions are found to be 4 mbar acetone pressure and 745+/-20 V anode voltage. The count rate obtained by us is about a factor of 3 higher than what has been reported earlier for the acetone detector. Unlike other gas filled detectors, this detector works in the proportional region with very small dead time (4 micro sec). A detector band-pass of 0.48+/-0.01 eV FWHM is obtained.Comment: Review of Scientific Instruments 76, 066102 (2005

Low-Mass Dileptons at the CERN-SpS: Evidence for Chiral Restoration?

Using a rather complete description of the in-medium $\rho$ spectral function - being constrained by various independent experimental information - we calculate pertinent dilepton production rates from hot and dense hadronic matter. The strong broadening of the $\rho$ resonance entails a reminiscence to perturbative $q\bar q$ annihilation rates in the vicinity of the phase boundary. The application to dilepton observables in Pb(158AGeV)+Au collisions - incorporating recent information on the hadro-chemical composition at CERN-SpS energies - essentially supports the broadening scenario. Possible implications for the nature of chiral symmetry restoration are outlined.Comment: 6 pages ReVTeX including 5 eps-figure

Diazotrophic activity and ferric phosphate mineralizing ability in estuarine sulfate reducing bacteria

Twenty strainsofsulfate reducing bacteria were isolated from water and sediments of Cochin backwaters, India. Five of them were identified as Desulfovibrio desulfuricans and fifteen as Desulfotomaculum orientis. All the Desulfovibrio were isolated from sediments whereas Desulfotomaculum was present in both water and sediment. All the bacteria grew at pH of slightly alkaline reaction and lowered the Eh from -105 to - 270 m V of the growth medium. Complete reduction of sulfate to sulfide by the bacteria was evidenced by blackening of Post gate culture media. All isolates were able to fix dinitrogen in anaerobic N-free modified Postgate broth. In addition to nitrogen fixing ability, 5 of the Desulfotomaculum and 3 of the Desulfovibrio were able to produce soluble phosphorus in growth medium from insoluble FePO4. A scheme for FePO4 mineralization in marine and estuarine sediments has been proposed

Chitinolytic bacteria in Penaeus indicus

Quantitative distribution of chitinolytic bacteria from the hepatopancreas, stomach and intestine of a commercially important marine prawn Penaeus indicus was studied. Twenlyfive representative bacteria were isolated from colonies forming well defined clear zones on chitin agar medium and were identified. Eighteen of the isolates were members of the genus Vibrio and the rest were members of the genus Pseudomonas

Influence of Ni doping on the electronic structure of Ni_2MnGa

The modifications in the electronic structure of Ni_{2+x}Mn_{1-x}Ga by Ni doping have been studied using full potential linearized augmented plane wave method and ultra-violet photoemission spectroscopy. Ni 3d related electron states appear due to formation of Ni clusters. We show the possibility of changing the minority-spin DOS with Ni doping, while the majority-spin DOS remains almost unchanged. The total magnetic moment decreases with excess Ni. The total energy calculations corroborate the experimentally reported changes in the Curie temperature and the martensitic transition temperature with x.Comment: 4 pages, 4 figures, accepted in Phys. Rev.

Local simulation of singlet statistics for restricted set of measurement

The essence of Bell's theorem is that, in general, quantum statistics cannot be reproduced by local hidden variable (LHV) model. This impossibility is strongly manifested while analyzing the singlet state statistics for Bell-CHSH violations. In this work, we provide various subsets of two outcome POVMs for which a local hidden variable model can be constructed for singlet state.Comment: 2 column, 5 pages, 4 figures, new references, abstract modified, accepted in JP