363 research outputs found

    First results from the LUCID-Timepix spacecraft payload onboard the TechDemoSat-1 satellite in Low Earth Orbit

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    The Langton Ultimate Cosmic ray Intensity Detector (LUCID) is a payload onboard the satellite TechDemoSat-1, used to study the radiation environment in Low Earth Orbit (\sim635km). LUCID operated from 2014 to 2017, collecting over 2.1 million frames of radiation data from its five Timepix detectors on board. LUCID is one of the first uses of the Timepix detector technology in open space, with the data providing useful insight into the performance of this technology in new environments. It provides high-sensitivity imaging measurements of the mixed radiation field, with a wide dynamic range in terms of spectral response, particle type and direction. The data has been analysed using computing resources provided by GridPP, with a new machine learning algorithm that uses the Tensorflow framework. This algorithm provides a new approach to processing Medipix data, using a training set of human labelled tracks, providing greater particle classification accuracy than other algorithms. For managing the LUCID data, we have developed an online platform called Timepix Analysis Platform at School (TAPAS). This provides a swift and simple way for users to analyse data that they collect using Timepix detectors from both LUCID and other experiments. We also present some possible future uses of the LUCID data and Medipix detectors in space.Comment: Accepted for publication in Advances in Space Researc

    SETI and Democracy

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    There is a wide-ranging debate about the merits and demerits of searching for, and sending messages to, extraterrestrial intelligences (SETI and METI). There is however reasonable (but not universal) consensus that replying to a message from an extraterrestrial intelligence should not be done unilaterally, without consultation with wider society and the rest of the world. But how should this consultation actually work? In this paper we discuss various ways that decision making in such a scenario could be done democratically, and gain legitimacy. In particular we consider a scientist-led response, a politician-led response, deciding a response using a referendum, and finally using citizens' assemblies. We present the results of a survey of a representative survey of 2,000 people in the UK on how they thought a response should best be determined, and finally discuss parallels to how the public is responding to scientific expertise in the COVID-19 PandemicComment: 11 pages, 2 figures, accepted Acta Astronautic

    Initiation of communication by persons with severe aphasia during group treatment

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    The viability of group treatment in inpatient rehabilitation facilities (IRFs) is at a crossroads. While the Centers for Medicare and Medicaid Services (CMS) has not yet established standards for group therapy in IRFs, they have stated that the standard for care in these settings is individualized therapy (Department of Health and Human Services, Centers for Medicare & Medicaid Services, 2009). CMS limitations of the size and frequency of group therapy in other settings suggests that CMS believes group treatment is of a lesser quality when compared with individual treatment. This is a critical time for research demonstrating the unique benefits of SLP group treatment in acute rehabilitatio

    Identification of a novel tetragonally compressed six-coordinate copper(II) complex: preparation and characterization of a 3-chloroanilinium copper chloride complex, (3-chloroanilinium)8[CuCl6]Cl4

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    A monomeric hexachlorocuprate(II) ion has been found in the compound (3-chloroanilinium) 8[CuCl6]Cl 4, CuC4,H56C18N8 . The compound crystallizes in the triclinic space group P1 with unit cell dimensions a = 8.5488(16) A, b = 13.964(6) A, c = 14.273(7) A, a = 90.46(4)*, B = 107.82(3)0, and y = 102.11(3) ° with Z = 1. The coordination about the discrete [CuCl6]4-, ion is that of a tetragonally compressed octahedron with bond distances Cu-Cl(1) = 2.2773(1i) A, Cu-Cl(2) = 2.6061(18) A, and Cu-Cl(3) = 2.6086(20) A. The two short bond distances are on the ordec frequently seen for copper-chloride bonds, but the remaining four bond distances are remarkably long for in-plane 4 + 2 coordination. The Cl(l)-Cu-Cl(la), Cl(2)-Cu-Cl(2a), and Cl(3)-Cu-Cl(3a) angles are strictly 180 °, and the 12 remaining Cl(i)-Cu-Cl(j) angles differ from 90° by 0.4 to 1.0°. The EPR spectrum of a powdered sample is of the "reversed" nature indicative of a 2A ground state with g, = 2.06 and gl = 2.19. Magnetic susceptibility data provide evidence for antiferromagnetic interactions between the hexachlorocuprate cations, since there is a maximum in the magnetic susceptibility near 10 K. The data may be approximated by Heisenberg chain theory with J = -5.6 cm', g = 2.00, and an interchain exchange parameter J1 = -2.1 cm-1

    Spectral age distribution for radio-loud active galaxies in the XMM-LSS field

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    Jets of energetic particles, as seen in FR type-I and FR type-II sources, ejected from the center of Radio-Loud AGN affect the sources surrounding intracluster medium/intergalactic medium. Placing constraints on the age of such sources is important in order to measure the jet powers and determine the effects on feedback. To evaluate the age of these sources using spectral age models, we require high-resolution multi-wavelength data. The new sensitive and high-resolution MIGHTEE survey of the XMM-LSS field along with data from the Low Frequency Array (LOFAR) and the Giant Metrewave Radio Telescope (GMRT) provide data taken at different frequencies with similar resolution, which enables us to determine the spectral age distribution for radio loud AGN in the survey field. In this study we present a sample of 28 radio galaxies with their best fitting spectral age distribution analyzed using the Jaffe-Perola (JP) model on a pixel-by-pixel basis. Fits are generally good and objects in our sample show maximum ages within the range of 2.8 Myr to 115 Myr with a median of 8.71 Myr. High-resolution maps over a range of frequencies are required to observe detailed age distributions for small sources and high-sensitivity maps will be needed in order to observe fainter extended emission. We do not observe any correlation between the total physical size of the sources and their age and we speculate both dynamical models and the approach to spectral age analysis may need some modification to account for our observations.Comment: 20 pages, 9 figure

    Analysis of a threshold model of social contagion on degree-correlated networks

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    We analytically determine when a range of abstract social contagion models permit global spreading from a single seed on degree-correlated random networks. We deduce the expected size of the largest vulnerable component, a network's tinderbox-like critical mass, as well as the probability that infecting a randomly chosen individual seed will trigger global spreading. In the appropriate limits, our results naturally reduce to standard ones for models of disease spreading and to the condition for the existence of a giant component. Recent advances in the distributed, infinite seed case allow us to further determine the final size of global spreading events, when they occur. To provide support for our results, we derive exact expressions for key spreading quantities for a simple yet rich family of random networks with bimodal degree distributions.Comment: 7 Pages, 1 figure, submitted to Phys. Rev.

    A minimally invasive technique for closing an iatrogenic subclavian artery cannulation using the Angio-Seal closure device: two case reports

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    <p>Abstract</p> <p>Introduction</p> <p>In the two cases described here, the subclavian artery was inadvertently cannulated during unsuccessful access to the internal jugular vein. The puncture was successfully closed using a closure device based on a collagen plug (Angio-Seal, St Jude Medical, St Paul, MN, USA). This technique is relatively simple and inexpensive. It can provide clinicians, such as intensive care physicians and anesthesiologists, with a safe and straightforward alternative to major surgery and can be a life-saving procedure.</p> <p>Case presentation</p> <p>In the first case, an anesthetist attempted ultrasound-guided access to the right internal jugular vein during the preoperative preparation of a 66-year-old Caucasian man. A 7-French (Fr) triple-lumen catheter was inadvertently placed into his arterial system. In the second case, an emergency physician inadvertently placed a 7-Fr catheter into the subclavian artery of a 77-year-old Caucasian woman whilst attempting access to her right internal jugular vein. Both arterial punctures were successfully closed by means of a percutaneous closure device (Angio-Seal). No complications were observed.</p> <p>Conclusions</p> <p>Inadvertent subclavian arterial puncture can be successfully managed with no adverse clinical sequelae by using a percutaneous vascular closure device. This minimally invasive technique may be an option for patients with non-compressible arterial punctures. This report demonstrates two practical points that may help clinicians in decision-making during daily practice. First, it provides a practical solution to a well-known vascular complication. Second, it emphasizes a role for proper vascular ultrasound training for the non-radiologist.</p

    SB04-22/23: Resolution Authorizing Approval of Staff Senate Signature of Bear Necessities Statement to University Administration

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    Passed during May 10, 2023 Staff Senate meeting. Documents from the May 10, 2023 meeting of the University of Montana S by University of Montana--Missoula. Staff Senate (umt.edu) Resolution authorizing approval of Staff Senate to sign support to the ASUM Bear Necessities statement to the University of Montana Administration. Resolution Authored by Kat Cowley. Additional Authors, including Cowley, listed for letter. Letter discusses concerns regarding the status of marginalized and vulnerable student populations and offers suggestions on some ways the University of Montana can support students at a basic human level. These include continued advocacy for increase support from the State of Montana, increased housing availability, meal plan affordability, open education resources, campus accessibility, and addressing staffing issues
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