Determination of transition frequencies in a single 138^{138}Ba+^{+} ion

Transition frequencies between low-lying energy levels in a single trapped $^{138}$Ba$^{+}$ ion have been measured with laser spectroscopy referenced to an optical frequency comb. By extracting the frequencies of one-photon and two-photon components of the line shape using an eight-level optical Bloch model, we achieved 0.1 MHz accuracy for the 5d $^{2}$D$_{3/2}$ - 6p $^{2}$P$_{1/2}$ and 6s $^{2}$S$_{1/2}$ - 5d $^{2}$D$_{3/2}$ transition frequencies, and 0.2 MHz for the 6s $^{2}$S$_{1/2}$ - 6p $^{2}$P$_{1/2}$ transition frequency.Comment: 5 pages, 7 figures, submitted to Phys. Rev.

Simulation of marine boundary layer characteristics using a 1-D PBL model over the Bay of Bengal during BOBMEX-99

The characteristic features of the marine boundary layer (MBL) over the Bay of Bengal during the southwest monsoon and the factors influencing it are investigated. The Bay of Bengal and Monsoon Experiment (BOBMEX) carried out during July-August 1999 is the first observational experiment under the Indian Climate Research Programme (ICRP). A very high-resolution data in the vertical was obtained during this experiment, which was used to study the MBL characteristics off the east coast of India in the north and south Bay of Bengal. Spells of active and suppressed convection over the Bay were observed, of which, three representative convective episodes were considered for the study. For this purpose a one-dimensional multi-level PBL model with a TKE-ε closure scheme was used. The soundings, viz., the vertical profiles of temperature, humidity, zonal and meridional component of wind, obtained onboard ORV Sagar Kanya and from coastal stations along the east coast are used for the study. The temporal evolution of turbulent kinetic energy, marine boundary layer height (MBLH), sensible and latent heat fluxes and drag coefficient of momentum are simulated for different epochs of monsoon and monsoon depressions during BOBMEX-99.The model also generates the vertical profiles of potential temperature, specific humidity, zonal and meridional wind. These simulated values compared reasonably well with the observations available from BOBMEX

Tachyon warm inflationary universe models

Warm inflationary universe models in a tachyon field theory are studied. General conditions required for these models to be realizable are derived and discussed. We describe scalar perturbations (in the longitudinal gauge) and tensor perturbations for these scenarios. We develop our models for a constant dissipation parameter $\Gamma$ in one case and one dependent on $\phi$ in the other case. We have been successful in describing such of inflationary universe models. We use recent astronomical observations for constraining the parameters appearing in our model. Also, our results are compared with their analogous found in the cool inflationary case.Comment: 21 pages, Accepted by JCA

Conserved variable analysis of the marine boundary layer and air-sea exchange processes using BOBMEX-Pilot data sets

The present study is based on the observed features of the MBL (Marine Boundary Layer) during the Bay of Bengal and Monsoon Experiment (BOBMEX) - Pilot phase. Conserved Variable Analysis (CVA) of the conserved variables such as potential temperature, virtual potential temperature, equivalent potential temperature, saturation equivalent potential temperature and specific humidity were carried out at every point of upper air observation obtained on board ORV Sagar Kanya. The values are estimated up to a maximum of 4 km to cover the boundary layer. The Marine Boundary Layer Height is estimated from the conserved thermodynamic profiles. During the disturbed period when the convective activity is observed, the deeper boundary layers show double mixing line structures. An attempt is also made to study the oceanic heat budget using empirical models. The estimated short-wave radiation flux compared well with the observations

Tomographic approach to resolving the distribution of LISA Galactic binaries

The space based gravitational wave detector LISA is expected to observe a large population of Galactic white dwarf binaries whose collective signal is likely to dominate instrumental noise at observational frequencies in the range 10^{-4} to 10^{-3} Hz. The motion of LISA modulates the signal of each binary in both frequency and amplitude, the exact modulation depending on the source direction and frequency. Starting with the observed response of one LISA interferometer and assuming only doppler modulation due to the orbital motion of LISA, we show how the distribution of the entire binary population in frequency and sky position can be reconstructed using a tomographic approach. The method is linear and the reconstruction of a delta function distribution, corresponding to an isolated binary, yields a point spread function (psf). An arbitrary distribution and its reconstruction are related via smoothing with this psf. Exploratory results are reported demonstrating the recovery of binary sources, in the presence of white Gaussian noise.Comment: 13 Pages and 9 figures high resolution figures can be obtains from http://www.phys.utb.edu/~rajesh/lisa_tomography.pd

ASSESSMENT OF USAGE OF ANTIBIOTIC AND THEIR PATTERN OF ANTIBIOTIC SENSITIVITY TEST AMONG CHILDHOOD FEVER

Objective: The present study evaluated the pattern of antibiotic usage and sensitivity pattern among children with fever. Methods: Questionnaires was specifically designed factoring patients' demographical profile, illness history, prescription regimen, antibiotic sensitivity report. Results: A total 157 prescriptions (80% OPD and 20% IPD) of children who visited Pediatric department complaining of fever were analyzed. Maximum children were of the age group between 2 – 3 yr (41%) with male/ female ratio of 1.54. Of total 157 patients, etiology of fever was diagnosed as Viral fever (60.15%), Fever with diarrhea(5%), Fever with seizure(3%) and Bacterial fever(31.8%). Average number of drugs per prescription was 3.27. Most common antibiotic used were Cefixime (42%), Cefotaxime (38%), Ceftriaxone (8%) and Amoxicillin (12%) among total antibiotic prescribed. Most commonly encountered drugs other than antibiotic prescribed were antipyretic: paracetamol syp (95%), Nasal decongestant: phenylephrine (70%), antihistaminic: Levocetrizine (65%), Multivitamin (60%), Zinc (20%) and ORS (20%) of prescription. Most widely prescribed antibiotic was Cefixime followed by cefotaxime. All the drugs were prescribed by brand names. positive Antibiotic sensitivity report was available for only 50 patients. Gram positive microbes like Staphylococcus species was isolated in 26 % cases and Streptococcus species in 6 % cases. These gram positive microbes were 100% sensitive to Cefotaxime, tetracycline, linezolid, Ampicillin etc. The gram negative microbes isolated were E. coli (5 %), Acenatobacter species (30 %), salmonella typhi (12%), and Klebsiella sp( 21%). All of them were sensitive to Cefotaxime, Pefloxacin, Ofloxacin, Cefuroxime, etc. Conclusion: Antibiotic sensitivity of blood culture studies demonstrated that both gram positive and gram negative bacteria showed maximum sensitivity to Cefotaxime. The most commonly prescribed antibiotic encountered in the present study was Cefixime followed by Cefotaxime

Prediction of Solubility of Carbonitrides in High Strength Low Alloy Steel

High Strength Low Alloy Steels are of particular interest for large submarines, offshore structures, line-pipe and other structural applications that require a combination of strength and toughness

A Spin-Mechanical Device for Detection and Control of Spin Current by Nanomechanical Torque

We propose a spin-mechanical device to control and detect spin currents by mechanical torque. Our hybrid nano-electro-mechanical device, which contains a nanowire with a ferromagnetic-nonmagnetic interface, is designed to measure or induce spin polarized currents. Since spin carries angular momentum, a spin flip or spin transfer process involves a change in angular momentum--and hence, a torque--which enables mechanical measurement of spin flips. Conversely, an applied torque can result in spin polarization and spin current.Comment: 6 pages, 2 figure