2,177 research outputs found

    Reckless Driving--Is It a Distinguishable Offense

    Get PDF

    Synchrotron Emission from Dark Matter in Galactic Subhalos. A Look into the Smith Cloud

    Full text link
    One of the key predictions of the WIMP paradigm for Dark Matter (DM) is that DM particles can annihilate into charged particles. These annihilations will proceed in e.g. Galactic subhalos such as dwarf Galaxies or, as recently pointed out, high velocity clouds such as the "Smith Cloud". In this note, we focus on the radio emission associated with DM annihilations into electrons and positrons occurring in the Smith Cloud. The phenomenology of this emission is discussed in quite some detail. We argue that the uncertainties in the propagation can be captured by the typical diffusion-loss length parameter (Syrovatskii variable) but that the angle-integrated radio fluxes are independent of the propagation. We conclude that if the Smith Cloud is indeed dominated by DM, radio signals from DM annihilation stand out amongst other messengers. Furthermore, low frequencies such as the ones observed by e.g. the Low Frequency Array (LOFAR) and the next-generation Square Kilometre Array (SKA) are optimal for searches for DM in the Smith Cloud. As a practical application, we set conservative constraints on dark matter annihilation cross section using data of continuum radio emission from the Galaxy at 22 MHz and at 1.4 GHz. Stronger constraints could be reached by background subtraction, exploiting the profile and frequency dependence of the putative DM signal. We set stronger but tentative limits using the median noise in brightness temperature from the Green Bank Telescope and the LOFAR sensitivities.Comment: 23 pages, 17 figures. Extended discussion on how the limits/forecasts are obtained. Matches published versio

    Choppy Waters

    Get PDF
    The movement toward a uniform standard for confidentiality in mediation among the states is one that from the outset casts off into choppy waters, marked by pitching cross-currents of remarkable force

    Major Step Forward: Proposed Uniform Mediation Act Goes Public for Comments

    Get PDF
    The move toward a simplified and uniform law for mediation takes an important step forward this summer, with the release of the first integrated draft of the proposed Uniform Mediation Act. The act is being drafted by cooperating committees of the American Bar Association Section of Dispute Resolution and the National Conference of Commissioners on Uniform State Laws. If enacted and adopted uniformly, it would replace the hundreds of pages of complex and often conflicting statutes across the country with a few short pages of simple, accessible, and helpful rules

    Kinetics and Mechanism of Oxidation of N-acetyl-d-penicillamine in Acidified Iodate and Aqueous Iodine

    Get PDF
    The oxidation of the biologically-active thiol, N-acetyl-d-penicillamine (NDPen) by acidified iodate and aqueous iodine has been studied. The stoichiometry of the reaction is 1:1 in which the thiol (RSH) is oxidized to its sulfonic acid (RSO3H) without cleavage of the C-S bond. In excess acidified iodate the reaction displayed a short induction period, followed by formation of aqueous iodine. Overall stoichiometry in excess iodate was 6:5: 6 IO3 –+5RSH+6H+→5 RSO3H+3I2(aq)+3H2O. The direct reaction of aqueous iodine and was relatively fast, over within 100 ms and had a stoichiometry of 1:3: 3 I2(aq) + RSH+3H2O →RSO3H+6 I– + 6 H+. The reaction is essentially diffusion-controlled and our stopped-flow with a mixing time limitation of 1.00 ms could only catch the reaction of the last iodine molecule. This reaction is, however, strongly inhibited by the product of reaction, I– . This is due to the formation of the relatively inert triiodide anion: I2(aq)+I–→I3 –. Mass spectrometry results showed that the reaction proceeds through the sulfinic acid with negligible stabilization of the sulfenic acid. In excess of reductant, the dimeric species is the favoured product due to a rapid condensation-type reaction between the electrophilic unstable sulfenic acid and unreacted thiol.Keywords: Biological thiols, bioactivation, oxidations, oxyhalogen chemistry

    Testing for entanglement with periodic coarse-graining

    Get PDF
    Continuous variables systems find valuable applications in quantum information processing. To deal with an infinite-dimensional Hilbert space, one in general has to handle large numbers of discretized measurements in tasks such as entanglement detection. Here we employ the continuous transverse spatial variables of photon pairs to experimentally demonstrate novel entanglement criteria based on a periodic structure of coarse-grained measurements. The periodization of the measurements allows for an efficient evaluation of entanglement using spatial masks acting as mode analyzers over the entire transverse field distribution of the photons and without the need to reconstruct the probability densities of the conjugate continuous variables. Our experimental results demonstrate the utility of the derived criteria with a success rate in entanglement detection of 60%\sim60\% relative to 73447344 studied cases.Comment: V1: revtex4, 10 pages, 4 figures + supp. material (4 pages, 1 figure) V2: Substantial revisions implemented both in theory and experimental data analysi
    corecore