858 research outputs found

    On the Distribution of Generating Functions

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135518/1/blms0113.pd

    Spin torque, tunnel-current spin polarization and magnetoresistance in MgO magnetic tunnel junctions

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    We examine the spin torque (ST) response of magnetic tunnel junctions (MTJs) with ultra-thin MgO tunnel barrier layers to investigate the relationship between the spin-transfer torque and the tunnel magnetoresistance (TMR) under finite bias. We find that the spin torque per unit current exerted on the free layer decreases by less than 10% over a bias range where the TMR decreases by over 40%. We examine the implications of this result for various spin-polarized tunneling models and find that it is consistent with magnetic-state-dependent effective tunnel decay lengths.Comment: 4 pages, 3 figure

    Some remarks on Vinogradov's mean value theorem and Tarry's problem

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    Let W(k, 2) denote the, least number s for which the system of equations has a solution with . We show that for large k one has W(k, 2)≦1/2k 2 (log k +loglog k + O (1)), and moreover that when K is large, one has W(k, 2)≦1/2k(k+1)+1 for at least one value k in the interval [ K, K 3/4+ε ]. We show also that the least s for which the expected asymptotic formula holds for the number of solutions of the above system of equations, inside a box, satisfies s ≦ k 2 (log k + O (loglog k ).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41627/1/605_2005_Article_BF01320189.pd

    Simultaneous genome sequencing of symbionts and their hosts

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    Second-generation sequencing has made possible the sequencing of genomes of interest for even small research groups. However, obtaining separate clean cultures and clonal or inbred samples of metazoan hosts and their bacterial symbionts is often difficult. We present a computational pipeline for separating metazoan and bacterial DNA in silico rather than at the bench. The method relies on the generation of deep coverage of all the genomes in a mixed sample using Illumina short-read sequencing technology, and using aggregate properties of the different genomes to identify read sets belonging to each. This inexpensive and rapid approach has been used to sequence several nematode genomes and their bacterial endosymbionts in the last year in our laboratory and can also be used to visualize and identify unexpected contaminants (or possible symbionts) in genomic DNA samples. We hope that this method will enable researchers studying symbiotic systems to move from gene-centric to genome-centric approaches

    Living with AMD treatment: Patient experiences of being treated with Ranibizumab (Lucentis) intravitreal injections

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    This study reports the results of a qualitative study of patient experiences of receiving treatment for wet age-related macular degeneration with ranibizumab (Lucentis)(R). Treatment involved monthly hospital visits for assessment and, where required, an intravitreal Lucentis injection. Qualitative narrative interviews were conducted with 22 patients, 18 of whom received treatment and were interviewed at two points during their treatment journey. Interviews allowed participants to reflect on their experiences of being assessed for and receiving this treatment. Overall, treated participants reported that while they had been apprehensive about treatment, the actual experience of it was far less unpleasant than they had expected. However, the data also revealed a number of issues surrounding the provision of information about treatment, as well as service delivery issues, which had considerable impact upon their experience

    Searching for gravitational waves from known pulsars

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    We present upper limits on the amplitude of gravitational waves from 28 isolated pulsars using data from the second science run of LIGO. The results are also expressed as a constraint on the pulsars' equatorial ellipticities. We discuss a new way of presenting such ellipticity upper limits that takes account of the uncertainties of the pulsar moment of inertia. We also extend our previous method to search for known pulsars in binary systems, of which there are about 80 in the sensitive frequency range of LIGO and GEO 600.Comment: Accepted by CQG for the proceeding of GWDAW9, 7 pages, 2 figure

    Upper limits on the strength of periodic gravitational waves from PSR J1939+2134

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    The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times 102210^{-22}.Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July 200
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