158 research outputs found

    Early- Onset Stroke and Vasculopathy Associated with Mutations in ADA2

    Get PDF
    Adenosine deaminase 2 (ADA2) is an enzyme involved in purine metabolism and a growth factor that influences the development of endothelial cells and leukocytes. This study shows that defects in ADA2 cause recurrent fevers, vascular pathologic features, and mild immunodeficiency. Patients with autoinflammatory disease sometimes present with clinical findings that encompass multiple organ systems.(1) Three unrelated children presented to the National Institutes of Health (NIH) Clinical Center with intermittent fevers, recurrent lacunar strokes, elevated levels of acute-phase reactants, livedoid rash, hepatosplenomegaly, and hypogammaglobulinemia. Collectively, these findings do not easily fit with any of the known inherited autoinflammatory diseases. Hereditary or acquired vascular disorders can have protean manifestations yet be caused by mutations in a single gene. Diseases such as the Aicardi-Goutieres syndrome,(2),(3) polypoidal choroidal vasculopathy,(4) sickle cell anemia,(5) livedoid vasculopathy,(6) and the small-vessel vasculitides(7),(8) are examples of systemic ...</p

    Large-Eddy Simulations of Magnetohydrodynamic Turbulence in Heliophysics and Astrophysics

    Get PDF
    We live in an age in which high-performance computing is transforming the way we do science. Previously intractable problems are now becoming accessible by means of increasingly realistic numerical simulations. One of the most enduring and most challenging of these problems is turbulence. Yet, despite these advances, the extreme parameter regimes encountered in space physics and astrophysics (as in atmospheric and oceanic physics) still preclude direct numerical simulation. Numerical models must take a Large Eddy Simulation (LES) approach, explicitly computing only a fraction of the active dynamical scales. The success of such an approach hinges on how well the model can represent the subgrid-scales (SGS) that are not explicitly resolved. In addition to the parameter regime, heliophysical and astrophysical applications must also face an equally daunting challenge: magnetism. The presence of magnetic fields in a turbulent, electrically conducting fluid flow can dramatically alter the coupling between large and small scales, with potentially profound implications for LES/SGS modeling. In this review article, we summarize the state of the art in LES modeling of turbulent magnetohydrodynamic (MHD) ows. After discussing the nature of MHD turbulence and the small-scale processes that give rise to energy dissipation, plasma heating, and magnetic reconnection, we consider how these processes may best be captured within an LES/SGS framework. We then consider several special applications in heliophysics and astrophysics, assessing triumphs, challenges,and future directions

    Snow White in different guises: Interlingual and intercultural exchanges between grandparents and young children at home in East London

    Get PDF
    Grandparents play a significant role in childcare and one activity that frequently occurs within this context is story-reading. However, relatively little attention has been given to the potential part that grandparents can play in terms of language and literacy development of young children.This article reports on work investigating the interlingual and intercultural exchanges occurring in a home setting in East London. In particular, it focuses on how the traditional heritage pattern of story and rhyme reading by a grandmother of Bengali origin is fused with practices experienced by her six-year old grandchild.The data reveal not only the multiple worlds inhabited by the grandchild during story-reading but also the syncretism of these worlds on a number of levels.This article contributes to the small but growing body of investigation into the reading styles occurring within families from different cultural backgrounds

    Measurement of prompt hadron production ratios in pppp collisions at s=\sqrt{s} = 0.9 and 7 TeV

    Get PDF
    The charged-particle production ratios pˉ/p\bar{p}/p, K−/K+K^-/K^+, π−/π+\pi^-/\pi^+, (p+pˉ)/(π++π−)(p + \bar{p})/(\pi^+ + \pi^-), (K++K−)/(π++π−)(K^+ + K^-)/(\pi^+ + \pi^-) and (p+pˉ)/(K++K−)(p + \bar{p})/(K^+ + K^-) are measured with the LHCb detector using 0.3nb−10.3 {\rm nb^{-1}} of pppp collisions delivered by the LHC at s=0.9\sqrt{s} = 0.9 TeV and 1.8nb−11.8 {\rm nb^{-1}} at s=7\sqrt{s} = 7 TeV. The measurements are performed as a function of transverse momentum pTp_{\rm T} and pseudorapidity η\eta. The production ratios are compared to the predictions of several Monte Carlo generator settings, none of which are able to describe adequately all observables. The ratio pˉ/p\bar{p}/p is also considered as a function of rapidity loss, Δy≡ybeam−y\Delta y \equiv y_{\rm beam} - y, and is used to constrain models of baryon transport.Comment: Incorrect entries in Table 2 corrected. No consequences for rest of pape

    Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

    Get PDF
    We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society

    Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

    Get PDF
    The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

    Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

    Get PDF
    [no abstract available

    Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV

    Get PDF
    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7  fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale
    • 

    corecore