5,507 research outputs found

    User fees, transport costs, and the ethics of exemption: how free is free ART?

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    The Southern African HIV Clinicians Society initiated an online discussion forum on ‘HIV Ethics and Policy' in 2007. The case study below concerns the ‘hidden' costs associated with access to antiretroviral therapy (ART), and discusses a number of proposed solutions to the problems faced by indigent patients with HIV/AIDS (to read the entire debate, see http://groups. google.com/group/policy-ethics/topics?start=10&sa=N). Southern African Journal of HIV Medicine Vol. 8 (2) 2007: pp. 52-5

    Studies on the inheritance of leaf blast resistance in rice

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    Studies on the inheritance of leaf blast resistance in seven differential varieties of rice tested against two Indian isolates of the international races IA-11 add ID-1 of Pyricularia oryzae Cav. under standardized experimental conditions revealed the presence of three dominant genes, one each in Zenith. Tetep and Ginga conferring resistance to IA-11 and two, one each in Zenith and Tetep, to the race ID-1. The genes of Zenith were independent of those of Tetep. C.l. 5309 possessed inhibitory genes inhibiting the resistance of Zenith but not of Telep. Mode of segregation of resistance o Norin 20 to the race IA-11 was found to be anamolous. Studies on the crosses among susecptible varieties showed the existence of dominant genes conferring susceptibility, two each in P.I. 180061 and Yakeiko. This is a new feature of the present studies and its utility in evolving homozygous recessive resistant varieties have been pointed out

    Diamond electro-optomechanical resonators integrated in nanophotonic circuits

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    Diamond integrated photonic devices are promising candidates for emerging applications in nanophotonics and quantum optics. Here we demonstrate active modulation of diamond nanophotonic circuits by exploiting mechanical degrees of freedom in free-standing diamond electro-optomechanical resonators. We obtain high quality factors up to 9600, allowing us to read out the driven nanomechanical response with integrated optical interferometers with high sensitivity. We are able to excite higher order mechanical modes up to 115 MHz and observe the nanomechanical response also under ambient conditions.Comment: 15 pages, 4 figure

    Evaporative Cooling of a Guided Rubidium Atomic Beam

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    We report on our recent progress in the manipulation and cooling of a magnetically guided, high flux beam of 87Rb^{87}{\rm Rb} atoms. Typically 7×1097\times 10^9 atoms per second propagate in a magnetic guide providing a transverse gradient of 800 G/cm, with a temperature ∼550\sim550 μ\muK, at an initial velocity of 90 cm/s. The atoms are subsequently slowed down to ∼60\sim 60 cm/s using an upward slope. The relatively high collision rate (5 s−1^{-1}) allows us to start forced evaporative cooling of the beam, leading to a reduction of the beam temperature by a factor of ~4, and a ten-fold increase of the on-axis phase-space density.Comment: 10 pages, 8 figure

    New limit for the half-life of double beta decay of 94^{94}Zr to the first excited state of 94^{94}Mo

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    Neutrinoless Double Beta Decay is a phenomenon of fundamental interest in particle physics. The decay rates of double beta decay transitions to the excited states can provide input for Nuclear Transition Matrix Element calculations for the relevant two neutrino double beta decay process. It can be useful as supplementary information for the calculation of Nuclear Transition Matrix Element for the neutrinoless double beta decay process. In the present work, double beta decay of 94^{94}Zr to the 21+2^{+}_{1} excited state of 94^{94}Mo at 871.1 keV is studied using a low background ∼\sim 230 cm3^3 HPGe detector. No evidence of this decay was found with a 232 g.y exposure of natural Zirconium. The lower half-life limit obtained for the double beta decay of 94Zr\rm^{94}Zr to the 21+2^{+}_{1} excited state of 94Mo\rm^{94}Mo is T1/2(0ν+2ν)>3.4×1019T_{1/2} (0\nu + 2\nu)> 3.4 \times 10^{19} y at 90% C.L., an improvement by a factor of ∼\sim 4 over the existing experimental limit at 90\% C.L. The sensitivity is estimated to be T1/2(0ν+2ν)>2.0×1019T_{1/2} (0\nu + 2\nu) > 2.0\times10^{19} y at 90% C.L. using the Feldman-Cousins method.Comment: 11 pages, 7 figures, Accepted in Eur. Phys. J.

    Rotational Bands and Electromagnetic Transitions of some even-even Neodymium Nuclei in J-Projected Hartree-Fock Model

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    Rotational structures of even-even 148−160^{148-160}Nd nuclei are studied with the self-consistent deformed Hartree-Fock (HF) and angular momentum (J) projection model. Spectra of ground band, recently observed K=4−K=4^{-}, K=5−K=5^{-} and a few more excited, positive and negative parity bands have been studied upto high spin values. Apart from these detailed electromagnetic properties (like E2, M1 matrix elements) of all the bands have been obtained. There is substantial agreement between our model calculations and available experimental data. Predictions are made about the band structures and electromagnetic properties of these nuclei. Some 4-qasiparticle K-isomeric bands and their electromagnetic properties are predicted.Comment: 20 page

    Parametrization of dark energy equation of state Revisited

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    A comparative study of various parametrizations of the dark energy equation of state is made. Astrophysical constraints from LSS, CMB and BBN are laid down to test the physical viability and cosmological compatibility of these parametrizations. A critical evaluation of the 4-index parametrizations reveals that Hannestad-M\"{o}rtsell as well as Lee parametrizations are simple and transparent in probing the evolution of the dark energy during the expansion history of the universe and they satisfy the LSS, CMB and BBN constraints on the dark energy density parameter for the best fit values.Comment: 11 page

    Inverted porphyrins and expanded porphyrins: an overview

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    Porphyrins and metallopophyrins have attracted the attention of chemists for the past 100 years or more owing to their widespread involvement in biology. More recently, synthetic porphyrins and porphyrin-like macrocycles have attracted the attention of researchers due to their diverse applications as sensitizers for photodynamic therapy, MRI contrasting agents, and complexing agents for larger metal ions and also for their anion binding abilities. The number of π-electrons in the porphyrin ring can be increased either by increasing the numberof conjugated double bonds between the pyrrole rings or by increasing the number of heterocyclic rings. Thus, 22π sapphyrins, 26π rubyrins, 30π heptaphyrins, 34π octaphyrins and higher cyclic polypyrrole analogues containing 40π, 48π, 64π, 80π and 96π systems have recently been reported in the literature. These macrocycles show rich structural diversity where normal and different kinds of inverted structures have been identified. In this review, an attempt has been made to collect the literature of the inverted porphyrins and expanded porphyrins reported until December 2001. Since themeso aryl expanded porphyrins have tendency to form both inverted and non-inverted structures more emphasis has been given to meso aryl expanded porphyrins

    Diagnosing Xpert MTB/RIF-negative TB: Impact and cost of alternative algorithms for South Africa

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    Background. Use of Xpert MTB/RIF is being scaled up throughout South Africa for improved diagnosis of tuberculosis (TB). A large proportion of HIV-infected patients with possible TB are Xpert-negative on their initial test, and the existing diagnostic algorithm calls for these patients to have sputum culture (Xpert followed by culture (X/C)). We modelled the costs and impact of an alternative diagnostic algorithm in which these cultures are replaced with a second Xpert test (Xpert followed by Xpert (X/X)).Methods. An existing population-level decision model was used. Costs were estimated from Xpert implementation studies and public sectorprice and salary data. The number of patients requiring diagnosis was estimated from the literature, as were rates of TB treatment uptakeand loss to follow-up. TB and HIV positivity rates were estimated from the national TB register and laboratory databases.Results. At national programme scale in 2014, X/X (R969 million/year) is less expensive than X/C R1 095 million/year), potentially saving R126million/year (US$17.4 million). However, because Xpert is less sensitive than culture, X/X diagnoses 2% fewer TB cases. This is partly offset byhigher expected treatment uptake with X/X due to the faster availability of results, resulting in 1% more patients initiating treatment under X/Xthan X/C. The cost per TB patient initiated on treatment under X/X is R2 682, which is 12% less than under X/C (R3 046).Conclusions. Modifying the diagnostic algorithm from X/C to X/X could provide rapid results, simplify diagnostic processes, improve HIV/TB treatment outcomes, and generate cost savings
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