Influence Of Uniaxial Pressure On The Critical Temperature For Long Delays In Gaas Junction Lasers

In this work we report on the influence of uniaxial pressure applied perpendicularly to junction laser on the behavior of the critical temperature for the onset of long delays in GaAs junction lasers. Experimental data showing this influence for lasers operating in a TE or TM polarization are presented and explained on the basis of a thermal theory of long delays and related phenomena.5195052505

Effect Of Uniaxial Pressure On The Threshold Current Of Double-heterostructure Gaas Lasers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)On application of uniaxial pressure perpendicular to the junction, the threshold current of GaAs double-heterostructure injection lasers at room temperature is observed to increase to a certain critical pressure P 0, and then decrease with further increase in pressure. A flip of the polarization of laser light occurs at P 0. This behavior can be explained using a model previously proposed to explain the reduction in threshold of homostructure GaAs lasers upon application of uniaxial pressure. © 1972 The American Institute of Physics.2141241252013/06322-0; FAPESP; São Paulo Research Foundation; FAPESP; São Paulo Research Foundation; 2013/11769-3; FAPESP; São Paulo Research Foundation; 2013/14185-2; FAPESP; São Paulo Research FoundationFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Rapid testing may not improve uptake of HIV testing and same day results in a rural South African community: a cohort study of 12,000 women

<p>Background: Rapid testing of pregnant women aims to increase uptake of HIV testing and results and thus optimize care. We report on the acceptability of HIV counselling and testing, and uptake of results, before and after the introduction of rapid testing in this area.</p> <p>Methods and Principal Findings: HIV counsellors offered counselling and testing to women attending 8 antenatal clinics, prior to enrolment into a study examining infant feeding and postnatal HIV transmission. From August 2001 to April 2003, blood was sent for HIV ELISA testing in line with the Prevention of Mother-to-Child Transmission (PMTCT) programme in the district. From May 2003 to September 2004 women were offered a rapid HIV test as part of the PMTCT programme, but also continued to have ELISA testing for study purposes. Of 12,323 women counselled, 5,879 attended clinic prior to May 2003, and 6,444 after May 2003 when rapid testing was introduced; of whom 4,324 (74.6%) and 4,810 (74.6%) agreed to have an HIV test respectively. Of the 4,810 women who had a rapid HIV test, only 166 (3.4%) requested to receive their results on the same day as testing, the remainder opted to return for results at a later appointment. Women with secondary school education were less likely to agree to testing than those with no education (AOR 0.648, p<0.001), as were women aged 21–35 (AOR 0.762, p<0.001) and >35 years (AOR 0.756, p<0.01) compared to those <20 years.</p> <p>Conclusions: Contrary to other reports, few women who had rapid tests accepted their HIV results the same day. Finding strategies to increase the proportion of pregnant women knowing their HIV results is critical so that appropriate care can be given.</p&gt

Threshold Behavior Of (gaal)as-gaas Lasers At Low Temperatures

The temperature dependence of the threshold current, differential quantum efficiency, and internal loss have been measured in the temperature range 10-293°K. The threshold current increases relatively slowly with temperature above 100°K and is independent of the impurity concentration. Theoretical calculation shows that this behavior is to be expected for a band-to-band transition that follows k selection. The threshold behavior at low temperatures (≤ 80°K) depends strongly on the type and concentration of the impurity. The relatively fast decrease in threshold below 100°K shows saturation for an active layer with n-type impurities or with high-concentration p-type impurities. The saturation is attributed to the carrier diffusion length becoming smaller than the active-layer thickness. The internal differential quantum efficiency is near unity and is independent of temperature. The internal loss, however, decreases with temperature due to reduction in free-carrier absorption.491293

Relationship of postpartum interval to estrus, body condition score, milk yield and blood biochemical parameters in Surti buffaloes (Bubalus bubalis)

The aim of the present investigation was to find out the relationship among postpartum interval to estrus, body condition score, milk yield and blood biochemical parameters of Surti buffaloes (Bubalus bubalis). The study was conducted on sixteen clinically healthy Surti buffaloes (parity 1-7) with normal parturition. These animals were divided into two groups on the basis of their postpartum interval to estrus (PPIE). Group 1 animals had PPIE ? 50 days whereas group 2 had PPIE > 50 days. Body condition score (BCS), milk yield and Blood samples were collected by jugular venipuncture on days starting from 6th day after calving thereafter at fortnight interval till 90th day postpartum. Blood serum parameters such as glucose, total protein, blood urea, creatinine, cholesterol, triglyceride, progesterone and estrogen were measured. Perusal of data revealed that animals having higher BCS on the day of estrus had significantly (P?0.05) shorter PPIE. There was non-significant effect of daily and cumulative 100 days milk yield on PPIE. Serum concentration of glucose and creatinine was significantly (P?0.05) higher for group 1 animals at most of the stages. There was non-significant difference between serum concentration of total protein, blood urea nitrogen and cholesterol between both the groups. Progesterone and Estradiol-17 ? concentrations were significantly (P?0.05) higher in group 1 animals than group 2 animals at different stages of this study

Synthesis and Antimicrobial Activity of 2-[2-(2,6-dichloro phenyl)amino]benzyl-3-(5-substituted phenyl-4,5-dihydro-1H-pyrazol-3-yl-amino)-6,8-dibromoquinazolin-4(3H)ones

A series of 2-[2-(2,6-dichlorophenyl)amino]benzyl-3-(5-substituted phenyl-4,5-dihydro-1H-pyrazol-3-yl-amino)-6,8-dibromoquinazolin-4(3H) ones 6a-m have been synthesized by the reaction of 2-[2-(2,6-dichlorophenyl)amino]benzyl-3-substituted phenylacrylamido-6,8-dibromoquinazolin-4(3H) ones 5a-m with hydrazine hydrate in the presence of glacial acetic acid. The chalcones 5a-m were prepared by the condensation of 2-[2-(2,6-dichlorophenyl)amino]benzyl-3-acetamido-6,8-dibromoquinazolin-4(3H)one 4 with different substituted aromatic aldehyde. The benzoxazinone 2 was synthesized from 2-[2-(2,6-dichlorophenyl)amino]phenyl acetyl chloride 1 on treatment with 3,5-dibromoanthranilic acid in pyridine, which on reaction with hydrazine hydrate and then on acetylation reaction yielded 4. The structures of these compounds have been elucidated by elemental analyses, IR, and NMR spectral data. The title compounds pyrazolyl-quinazolin-4(3H)ones 6a-m were evaluated for their antibacterial and antifungal activities in vitro

Production and Decay of D_1(2420)^0 and D_2^*(2460)^0

We have investigated $D^{+}\pi^{-}$ and $D^{*+}\pi^{-}$ final states and observed the two established $L=1$ charmed mesons, the $D_1(2420)^0$ with mass $2421^{+1+2}_{-2-2}$ MeV/c$^{2}$ and width $20^{+6+3}_{-5-3}$ MeV/c$^{2}$ and the $D_2^*(2460)^0$ with mass $2465 \pm 3 \pm 3$ MeV/c$^{2}$ and width $28^{+8+6}_{-7-6}$ MeV/c$^{2}$. Properties of these final states, including their decay angular distributions and spin-parity assignments, have been studied. We identify these two mesons as the $j_{light}=3/2$ doublet predicted by HQET. We also obtain constraints on {\footnotesize $\Gamma_S/(\Gamma_S + \Gamma_D)$} as a function of the cosine of the relative phase of the two amplitudes in the $D_1(2420)^0$ decay.Comment: 15 pages in REVTEX format. hardcopies with figures can be obtained by sending mail to: [email protected]

Measurement of the branching fraction for Υ(1S)→τ+τ−\Upsilon (1S) \to \tau^+ \tau^-

We have studied the leptonic decay of the $\Upsilon (1S)$ resonance into tau pairs using the CLEO II detector. A clean sample of tau pair events is identified via events containing two charged particles where exactly one of the particles is an identified electron. We find $B(\Upsilon(1S) \to \tau^+ \tau^-) = (2.61~\pm~0.12~{+0.09\atop{-0.13}})$. The result is consistent with expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS 94/1297, CLEO 94-20 (submitted to Physics Letters B

Quantum walks: a comprehensive review

Quantum walks, the quantum mechanical counterpart of classical random walks, is an advanced tool for building quantum algorithms that has been recently shown to constitute a universal model of quantum computation. Quantum walks is now a solid field of research of quantum computation full of exciting open problems for physicists, computer scientists, mathematicians and engineers. In this paper we review theoretical advances on the foundations of both discrete- and continuous-time quantum walks, together with the role that randomness plays in quantum walks, the connections between the mathematical models of coined discrete quantum walks and continuous quantum walks, the quantumness of quantum walks, a summary of papers published on discrete quantum walks and entanglement as well as a succinct review of experimental proposals and realizations of discrete-time quantum walks. Furthermore, we have reviewed several algorithms based on both discrete- and continuous-time quantum walks as well as a most important result: the computational universality of both continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing Journa

Magnetic Moments of JP=3/2+J^P=3/2^+ Heavy Baryons Using Effective Mass and Screened Charge Scheme

Magnetic moments of heavy charmed baryons with $J^P=3/2^+$ are predicted employing the concept of effective quark mass and screened charge of quark. We also extend our scheme to predict the $3/2^+ --> 1/2^+$ transition magnetic moments. A comparison of our results with the predictions obtained in recent models is presented.Comment: 19 pages, Accepted for publication in EPJ-