27,447 research outputs found

    Searching for binary coalescences with inspiral templates: Detection and parameter estimation

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    There has been remarkable progress in numerical relativity recently. This has led to the generation of gravitational waveform signals covering what has been traditionally termed the three phases of the coalescence of a compact binary - the inspiral, merger and ringdown. In this paper, we examine the usefulness of inspiral only templates for both detection and parameter estimation of the full coalescence waveforms generated by numerical relativity simulations. To this end, we deploy as search templates waveforms based on the effective one-body waveforms terminated at the light-ring as well as standard post-Newtonian waveforms. We find that both of these are good for detection of signals. Parameter estimation is good at low masses, but degrades as the mass of the binary system increases.Comment: 14 pages, submitted to proceedings of the NRDA08 meeting, Syracuse, Aug. 11-14, 200

    Multiscale reaction-diffusion algorithms: PDE-assisted Brownian dynamics

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    Two algorithms that combine Brownian dynamics (BD) simulations with mean-field partial differential equations (PDEs) are presented. This PDE-assisted Brownian dynamics (PBD) methodology provides exact particle tracking data in parts of the domain, whilst making use of a mean-field reaction-diffusion PDE description elsewhere. The first PBD algorithm couples BD simulations with PDEs by randomly creating new particles close to the interface which partitions the domain and by reincorporating particles into the continuum PDE-description when they cross the interface. The second PBD algorithm introduces an overlap region, where both descriptions exist in parallel. It is shown that to accurately compute variances using the PBD simulation requires the overlap region. Advantages of both PBD approaches are discussed and illustrative numerical examples are presented.Comment: submitted to SIAM Journal on Applied Mathematic

    Extracting Low-Lying Lambda Resonances Using Correlation Matrix Techniques

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    The lowest-lying negative-parity state of the Lambda is investigated in (2+1)-flavour full-QCD on the PACS-CS configurations made available through the ILDG. We show that a variational analysis using multiple source and sink smearings can extract a state lying lower than that obtained by using a standard fixed smeared source and sink operator alone.Comment: 3 pages, 1 figure, submitted to the proceedings of T(R)OPICAL QCD II, Cairns, Australia, 201

    Quantum Computing on Lattices using Global Two-Qubit Gate

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    We study the computation power of lattices composed of two dimensional systems (qubits) on which translationally invariant global two-qubit gates can be performed. We show that if a specific set of 6 global two qubit gates can be performed, and if the initial state of the lattice can be suitably chosen, then a quantum computer can be efficiently simulatedComment: 9 page

    SpaceOAR to improve dosimetric outcomes for monotherapy high-dose-rate prostate implantation in a patient with ulcerative colitis.

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    High-dose-rate (HDR) brachytherapy is an attractive option for patients receiving definitive radiation therapy for prostate cancer with decreased overall dose to the pelvis. However, ulcerative colitis increases rectal toxicity risk and may be a contraindication. A synthetic hydrogel, SpaceOAR (Augmentix Inc., Waltham, MA, USA), can facilitate the use of HDR brachytherapy for patients where rectal toxicity is a limiting factor. SpaceOAR gel (13.19 cc) was utilized in a monotherapy HDR prostate treatment with Ir-192 under transrectal ultrasound guidance, with the intention of decreasing rectal dose. SpaceOAR gel was inserted transperineally into the patient 18 days prior to the procedure. The HDR brachytherapy procedure was tolerated without incident. All planning constraints were met, and the following dosimetry was achieved: Prostate – V100% = 97.3%, V150% = 35%, V200% = 14.5%; Urethra – V118% = 0%; Rectum – D2 cc = 51.6%, V75% = 0 cc. The rectum-catheter spacing was on average between 6-8 mm. Average spacing for our 10 most recent patients without SpaceOAR was 3 mm. SpaceOAR did not hinder or distort ultrasound imaging or increase treatment time. SpaceOAR successfully increases catheter-rectal wall spacing and decreases rectal dose due to improved planning capabilities, while decreasing the likelihood of rectal perforation. One application of this tool is presented to mitigate potential toxicities associated with ulcerative colitis. At five months, one week, and one day follow-up, the patient reported no bowel issues following HDR brachytherapy. © 2018 Termedia Publishing House Ltd. All Rights Reserved

    The Human Thioesterase II Protein Binds to a Site on HIV-1 Nef Critical for CD4 Down-regulation

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    A HIV-1 Nef affinity column was used to purify a 35-kDa Nef-interacting protein from T-cell lysates. The 35-kDa protein was identified by peptide microsequence analysis as the human thioesterase II (hTE) enzyme, an enzyme previously identified in a yeast two-hybrid screen as a potential Nef-interacting protein. Immunofluorescence studies showed that hTE localizes to peroxisomes and that coexpression of Nef and hTE leads to relocalization of Nef to peroxisomes. Interaction of Nef and hTE was abolished by point mutations in Nef at residues Asp108, Leu112, Phe121, Pro122, and Asp123. All of these mutations also abrogated the ability of Nef to down-regulate CD4 from the surface of HIV-infected cells. Based on the x-ray and NMR structures of Nef, these residues define a surface on Nef critical for CD4 down-regulation. A subset of these mutations also affected the ability of Nef to down-regulate major histocompatibility complex class I. These results, taken together with previous studies, identify a region on Nef critical for most of its known functions. However, not all Nef alleles bind to hTE with high affinity, so the role of hTE during HIV infection remains uncertain

    Quantum privacy and quantum coherence

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    We derive a simple relation between a quantum channel's capacity to convey coherent (quantum) information and its usefulness for quantum cryptography.Comment: 6 pages RevTex; two short comments added 7 October 199
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