66 research outputs found

    Multilevel Semantic Analysis and Problem-Solving in the Flight Domain: Final Report: NASA Grant NCCI-52, July 11, 1981-July 10, 1982

    Get PDF
    Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNASA Grant NCCI-5

    Quantum Dynamics of Atomic Coherence in a Spin-1 Condensate: Mean-Field versus Many-Body Simulation

    Full text link
    We analyse and numerically simulate the full many-body quantum dynamics of a spin-1 condensate in the single spatial mode approximation. Initially, the condensate is in a ``ferromagnetic'' state with all spins aligned along the yy axis and the magnetic field pointing along the z axis. In the course of evolution the spinor condensate undergoes a characteristic change of symmetry, which in a real experiment could be a signature of spin-mixing many-body interactions. The results of our simulations are conveniently visualised within the picture of irreducible tensor operators.Comment: Accepted for publication for the special issue of "Optics Communications" on Quantum Control of Light and Matte

    Quantum interference with beamlike type-II spontaneous parametric down-conversion

    Full text link
    We implement experimentally a method to generate photon-number-path and polarization entangled photon pairs using ``beamlike'' type-II spontaneous parametric down-conversion (SPDC), in which the signal-idler photon pairs are emitted as two separate circular beams with small emission angles rather than as two diverging cones.Comment: 4 pages, two-colum

    Artificial Intelligence and Human Error Prevention: A Computer Aided Decision Making Approach: Technical Report No. 4: Survey and Analysis of Research on Learning Systems from Artificial Intelligence

    Get PDF
    Coordinated Science Laboratory was formerly known as Control Systems LaboratoryU.S. Department of Transportation / DOT FA79WA-4360 ABFederal Aviation Administratio

    A realistic example of chaotic tunneling: The hydrogen atom in parallel static electric and magnetic fields

    Full text link
    Statistics of tunneling rates in the presence of chaotic classical dynamics is discussed on a realistic example: a hydrogen atom placed in parallel uniform static electric and magnetic fields, where tunneling is followed by ionization along the fields direction. Depending on the magnetic quantum number, one may observe either a standard Porter-Thomas distribution of tunneling rates or, for strong scarring by a periodic orbit parallel to the external fields, strong deviations from it. For the latter case, a simple model based on random matrix theory gives the correct distribution.Comment: Submitted to Phys. Rev.

    Leituras da Orfandade família, Declínio do Pai e Ausência de Lei. uma Abordagem do Universo Ficcional de Rubem Fonseca.

    Get PDF
    RESUMO Observamos na contemporaneidade que a família assume formas diferentes às que possuía quando foi formulada, no século XVIII. Caracterizada por inúmeras transformações, já não possui uma estrutura tão fixa. A partir das narrativas de Henri, A força humana, Feliz ano novo e O cobrador, de Rubem Fonseca; não deixando de visitar outros trabalhos do escritor, discutiremos e examinaremos as configurações da família contemporânea. Neste sentido, analisaremos as representações da relação do sujeito com as novas estruturas familiares, o declínio da imago paterna e as consequências que essas transformações trazem à subjetividade, bem como as formas pelas quais tais relações são encenadas literariamente pelo escritor brasileir

    Cardiac magnetic resonance stress perfusion imaging for evaluation of patients with chest pain

    Get PDF
    Background: Stress cardiac magnetic resonance imaging (CMR) has demonstrated excellent diagnostic and prognostic value in single-center studies. Objectives: This study sought to investigate the prognostic value of stress CMR and downstream costs from subsequent cardiac testing in a retrospective multicenter study in the United States. Methods: In this retrospective study, consecutive patients from 13 centers across 11 states who presented with a chest pain syndrome and were referred for stress CMR were followed for a target period of 4 years. The authors associated CMR findings with a primary outcome of cardiovascular death or nonfatal myocardial infarction using competing risk-adjusted regression models and downstream costs of ischemia testing using published Medicare national payment rates. Results: In this study, 2,349 patients (63 ± 11 years of age, 47% female) were followed for a median of 5.4 years. Patients with no ischemia or late gadolinium enhancement (LGE) by CMR, observed in 1,583 patients (67%), experienced low annualized rates of primary outcome (4-fold higher annual primary outcome rate and a >10-fold higher rate of coronary revascularization during the first year after CMR. Patients with ischemia and LGE both negative had low average annual cost spent on ischemia testing across all years of follow-up, and this pattern was similar across the 4 practice environments of the participating centers. Conclusions: In a multicenter U.S. cohort with stable chest pain syndromes, stress CMR performed at experienced centers offers effective cardiac prognostication. Patients without CMR ischemia or LGE experienced a low incidence of cardiac events, little need for coronary revascularization, and low spending on subsequent ischemia testing. (Stress CMR Perfusion Imaging in the United States [SPINS]: A Society for Cardiovascular Resonance Registry Study; NCT03192891)

    Characteristics of contralateral carcinomas in patients with differentiated thyroid cancer larger than 1 cm

    Get PDF
    Purpose: Traditionally, total thyroidectomy has been advocated for patients with tumors larger than 1 cm. However, according to the ATA and NCCN guidelines (2015, USA), patients with tumors up to 4 cm are now eligible for lobectomy. A rationale for adhering to total thyroidectomy might be the presence of contralateral carcinomas. The purpose of this study was to describe the characteristics of contralateral carcinomas in patients with differentiated thyroid cancer (DTC) larger than 1 cm. Methods: A retrospective study was performed including patients from 17 centers in 5 countries. Adults diagnosed with DTC stage T1b-T3 N0-1a M0 who all underwent a total thyroidectomy were included. The primary endpoint was the presence of a contralateral carcinoma. Results: A total of 1

    Experimental progress in positronium laser physics

    Get PDF

    First Sagittarius A* event horizon telescope results. II. EHT and multiwavelength observations, data processing, and calibration

    Get PDF
    Instrumentatio
    corecore