209 research outputs found

    An Investigation of Selection Criteria for Admission to an Ontario University

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    The study investigated the effectiveness of five methods of university admission criteria in relation to academic results achieved after one year of university study. The admission criteria used were open admission, interview, teacher recommendations, Grade 13 academic achievement and SACU test scores. In addition these procedures were compared with a traditional method of admission at the university where the study was carried out. The characteristics of the admission groups were not significantly related to geographical distribution, sex distribution, government financial assistance, and attitude and personality questionnaire data. These characteristics were no different for these groups than the traditional method of selection and there was no significant difference between groups as to final first year grade point average or academic penalty i.e., probations and rustications. The open admissions group compared favourably on these latter variables with other admissions groups and particularly with the university's traditional method of admission

    An Evaluation of the Impact of Solitary Confinement on Offenders with Mental Illness

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    The primary goal of the current study is to examine the impact of solitary confinement (SC) on institutional misconducts in offenders with mental illness. The presentation focuses on the following questions: Does the experience of SC reduce institutional misconducts in offenders with mental illness? Does the length of time spent in SC influence subsequent institutional misconducts in offenders with mental illness

    100% RAG: Architectural Education | Historians and Critics, Volume 2, Number 6

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    100% RAG: Architectural Education | Historians and Critics, Syracuse School of Architecture, Student Newspaper, Volume 2, Number 6. Student newsletter from student contributors of Syracuse School of Architecture in 1977

    STROBE-X: X-Ray Timing and Spectroscopy on Dynamical Timescales from Microseconds to Years

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    The Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) probes strong gravity for stellar mass to supermassive black holes and ultradense matter with unprecedented effective area, high time-resolution, and good spectral resolution, while providing a powerful time-domain X-ray observatory.Comment: Accepted for Publication in Results in Physic

    Bright X-ray and Radio Pulses from a Recently Reactivated Magnetar

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    Magnetars are young, rotating neutron stars that possess larger magnetic fields (B ≈ 10¹³-10¹⁵G) and longer rotational periods (P ≈ 1-12 s) than ordinary pulsars. In contrast to rotation-powered pulsars, magnetar emission is thought to be fueled by the evolution and decay of their powerful magnetic fields. They display highly variable radio and X-ray emission, but the processes responsible for this behavior remain a mystery. We report the discovery of bright, persistent individual X-ray pulses from XTE J1810-197, a transient radio magnetar, using the Neutron star Interior Composition Explorer (NICER) following its recent radio reactivation. Similar behavior has only been previously observed from a magnetar during short time periods following a giant flare. However, the X-ray pulses presented here were detected outside of a flaring state. They are less energetic and display temporal structure that differs from the impulsive X-ray events previously observed from the magnetar class, such as giant flares and short X-ray bursts. Our high frequency radio observations of the magnetar, carried out simultaneously with the X-ray observations, demonstrate that the relative alignment between the X-ray and radio pulses varies on rotational timescales. No correlation was found between the amplitudes or temporal structure of the X-ray and radio pulses. The magnetar's 8.3 GHz radio pulses displayed frequency structure, which was not observed in the pulses detected simultaneously at 31.9 GHz. Many of the radio pulses were also not detected simultaneously at both frequencies, which indicates that the underlying emission mechanism producing these pulses is not broadband. We find that the radio pulses from XTE J1810-197 share similar characteristics to radio bursts detected from fast radio burst (FRB) sources, some of which are now thought to be produced by active magnetars

    Bright X-ray and Radio Pulses from a Recently Reactivated Magnetar

    Get PDF
    Magnetars are young, rotating neutron stars that possess larger magnetic fields (B ≈ 10¹³-10¹⁵G) and longer rotational periods (P ≈ 1-12 s) than ordinary pulsars. In contrast to rotation-powered pulsars, magnetar emission is thought to be fueled by the evolution and decay of their powerful magnetic fields. They display highly variable radio and X-ray emission, but the processes responsible for this behavior remain a mystery. We report the discovery of bright, persistent individual X-ray pulses from XTE J1810-197, a transient radio magnetar, using the Neutron star Interior Composition Explorer (NICER) following its recent radio reactivation. Similar behavior has only been previously observed from a magnetar during short time periods following a giant flare. However, the X-ray pulses presented here were detected outside of a flaring state. They are less energetic and display temporal structure that differs from the impulsive X-ray events previously observed from the magnetar class, such as giant flares and short X-ray bursts. Our high frequency radio observations of the magnetar, carried out simultaneously with the X-ray observations, demonstrate that the relative alignment between the X-ray and radio pulses varies on rotational timescales. No correlation was found between the amplitudes or temporal structure of the X-ray and radio pulses. The magnetar's 8.3 GHz radio pulses displayed frequency structure, which was not observed in the pulses detected simultaneously at 31.9 GHz. Many of the radio pulses were also not detected simultaneously at both frequencies, which indicates that the underlying emission mechanism producing these pulses is not broadband. We find that the radio pulses from XTE J1810-197 share similar characteristics to radio bursts detected from fast radio burst (FRB) sources, some of which are now thought to be produced by active magnetars

    SEXTANT X-Ray Pulsar Navigation Demonstration: Additional On-Orbit Results

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    The Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) is a technology demonstration enhancement to the Neutron-star Interior Composition Explorer (NICER) mission, a NASA Astrophysics Explorer Mission of Opportunity to the International Space Station, launched in June of 2017. In late 2017, SEXTANT successfully completed a first demonstration of in-space and autonomous X-ray pulsar navigation (XNAV). This form of navigation relies on processing faint signals from millisecond pulsars-rapidly rotating neutron stars that appear to pulsate in the X-ray band-and could potentially provide a GPS-like navigation capability applicable throughout the solar-system and beyond. In this work, we briefly review prior SEXTANT results and then present new results focusing on: making use of the high- flux but rotationally unstable Crab pulsar, and using XNAV to estimate position, velocity, and time in the presence of an imperfect local clock

    Nanoparticles in cigarette smoke; real-time undiluted measurements by a scanning mobility particle sizer

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    Cigarette smoke is a complex mixture of smoke constituents, often characterised by size-resolved particle distributions. Since descriptions of ultrafine particles <50 nm are absent, our aim was to explore the existence of these nanoparticles in fresh and undiluted cigarette smoke. We measured undiluted smoke particles real-time by a scanning mobility particle sizer with Faraday cup electrometer, integrated in our custom-made smoking machine. Cigarettes were smoked by 2 s puffs, 30 s puff intervals and 50 ml puff volume. We tested six different cigarettes (1–10 mg tar per cigarette) at ten particle size-ranges between 6 and 50 nm, and repeated measurements five times. The formation of nanoparticles in fresh cigarette smoke was observed over the entire range between 6 and 50 nm, and reproduced in all cigarettes. The highest mean yield was 8.8 × 109 (SD = 1.1 × 109) particles per cigarette at the largest particle size range by high-tar cigarettes. Nanoparticle counts appear to increase with particle size, claimed tar values and blocking of filter ventilation holes, and inversely with butt length. Fresh undiluted cigarette smoke contains large amounts of potentially toxic nanoparticles <50 nm. We recommend to further study nanoparticles in the characterisation of cigarette smoke
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