7,447 research outputs found

    Interferometric mapping of Magnetic fields: G30.79 FIR 10

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    We present polarization maps of G30.79 FIR 10 (in W43) from thermal dust emission at 1.3 mm and from CO J=212 \to 1 line emission. The observations were obtained using the Berkeley-Illinois-Maryland Association array in the period 2002-2004. The G30.79 FIR 10 region shows an ordered polarization pattern in dust emission, which suggests an hourglass shape for the magnetic field. Only marginal detections for line polarization were made from this region. Application of the Chandrashkar-Fermi method yielded Bpos1.7B_{pos} \approx 1.7 mG and a statistically corrected mass to magnetic flux ratio λC0.9\lambda_{C} \approx 0.9, or essentially critical.Comment: 11 pages, 2 Figures, Published in Ap

    Modeling of radiation damage in silicon solar cells

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    One MeV electron irradiation produces preponderantly isolated vacancy interstitial pairs. If neither of these defects is mobile, the concentration of each grows linearly with fluence. Annealing of damage depends on the nature of the damage. Vacancy interstitial pairs which are bound by an interaction such that they mutually annihilate rather than dissociate are termed close pairs; close pair recovery usually occurs at a lower temperature than the temperature at which long distance defect migration occurs. Annealing of the remaining frozen in damage occurs when a temperature is reached where the vacancy or interstitial is mobile; usually the interstitial is more mobile than the vacancy. The recovery occurs in two regimes which may be resoluable

    Об устойчивости движения математического маятника, взаимодействующего со струной

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    В линейной и нелинейной постановках решена задача об устойчивости стационарных движений однозвенного маятника в гибридной модели механической системы, состоящей из горизонтально закрепленной струны, нагруженной колеблющейся сосредоточенной массой.У лінійній і нелінійній постановках розв'язано задачу про стійкість стаціонарних рухів одноланкового маятника в гібридній моделі механічної системи, яка складається з горизонтально розміщеної струни, навантаженої коливною зосередженою масою.The problem of stability of the stationary motions of a single-mass pendulum in the hybrid model of one mechanical system is solved in the linear and nonlinear statements. The mechanical system consists of a string which is horizontally disposed and loaded by an oscillating localized mass

    Photoluminescence rings in Corbino disk at quantizing magnetic fields

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    Spatially resolved photoluminescence of modulation doped AlGaAs/GaAs heterojunction was investigated in a sample of Corbino disk geometry subject to strong perpendicular magnetic fields. Significant spatial modulation of the photoluminescence was observed in form of one or more concentric rings which travelled across the sample when the magnetic field strength was varied. A topology of the observed structure excludes the possibility of being a trace of an external current. The effect is attributed to formation of compressible and incompressible stripes in a 2DEG density gradient across the sample.Comment: 5 two-column pages, 4 figures (one of them in color

    Students as producers and active partners in enhancing equality and diversity: ‘culturosity’ at Canterbury Christ Church University

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    Equality and diversity of truths, of opportunity, of outcome, of dignity and of identities lie at the heart of the idea of university (Wolff, 1992, p. 68). However, despite the fact that the UK ‘has well-established equality law and practice’ and the Equality Act 2010 requires universities to implement changes that protect their students and employees from various forms and effects of discrimination, ‘inequality remains, albeit often in more complex and subtle forms than have been understood before’, argues David Ruebain (2012, p. 3). This study contributes to the discussion about equality and diversity practices in the university context by proposing strategies to embed into students’ learning community equality and diversity and subsequent graduate attributes. The case study is the Culturosity Project: an equality and diversity training initiative co-created by Dr Kasia Lech and a group of final-year students and graduates from Drama and Performing Arts programmes and delivered – as a Canterbury Christ Church University Partners in Learning project – to L4 and foundation-year students. The project was first delivered in 2015 and has now become part of student induction at the CCCU Faculty of Arts and Humanities

    Masses, luminosities and dynamics of galactic molecular clouds

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    Star formation in galaxies takes place in molecular clouds and the Milky Way is the only galaxy in which it is possible to resolve and study the physical properties and star formation activity of individual clouds. The masses, luminosities, dynamics, and distribution of molecular clouds, primarily giant molecular clouds in the Milky Way are described and analyzed. The observational data sets are the Massachusetts-Stony Brook CO Galactic Plane Survey and the IRAS far IR images. The molecular mass and infrared luminosities of glactic clouds are then compared with the molecular mass and infrared luminosities of external galaxies

    Interferometric Mapping of Magnetic fields: NGC2071IR

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    We present polarization maps of NGC2071IR from thermal dust emission at 1.3 mm and from CO J=212 \to 1 line emission. The observations were obtained using the Berkeley-Illinois-Maryland Association array in the period 2002-2004. We detected dust and line polarized emission from NGC2071IR that we used to constrain the morphology of the magnetic field. From CO J=212 \to 1 polarized emission we found evidence for a magnetic field in the powerful bipolar outflow present in this region. We calculated a visual extinction Av26A_{\rm{v}} \approx 26 mag from our dust observations. This result, when compared with early single dish work, seems to show that dust grains emit polarized radiation efficiently at higher densities than previously thought. Mechanical alignment by the outflow is proposed to explain the polarization pattern observed in NGC2071IR, which is consistent with the observed flattening in this source.Comment: 17 pages, 4 Figures, Accepted for publication in Ap

    Accelerating global ocean observing: monitoring the coastal ocean through broadly accessible, low-cost sensor networks

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wang, Z. A., Michel, A. P. M., & Mooney, T. A. Accelerating global ocean observing: monitoring the coastal ocean through broadly accessible, low-cost sensor networks. Marine Technology Society Journal, 55(3), (2021): 82–83, https://doi.org/10.4031/MTSJ.55.3.52.The global coastal ocean provides food and other critical resources to human societies. Yet this habitat, for which many depend, has experienced severe degradation from human activities. The rates of human-induced changes along the coast demand significantly improved coverage of ocean observations in order to support science-based decision making and policy formation tailored to specific regions. Our proposal envisions developing a global network of low-cost, easily produced and readily deployed oceanographic sensors for use on a wide variety of platforms in the coastal ocean. A substantially large number of these sensors can thus be installed on existing infrastructure, ships of opportunity, and fishing fleets, or even individually along the coast, particularly in vulnerable and disadvantaged regions. This would vastly increase the spatiotemporal resolution of the current data coverage along the coast, allowing greater equitable access. It would also offer significant opportunities for partnership with communities, NGOs, governments, and other stakeholders, as well as a wide range of commercial and industrial sectors to develop and deploy sensors in scalable networks transmitting data in near-real time. Finally, it presents a vastly lowered bar for participation by citizen scientists and other engaged members of the public to address location-specific coastal problems anywhere in the world.National Science Foundation; Project Title “Collaborative Research: IDBR: Type A: A High-resolution bio-sensor to simultaneously measure the behavior, vital rates and environment of key marine organisms”; Award Number 1455593 to ZAW and TAM

    Single and Composite Hot Subdwarf Stars in the Light of 2MASS Photometry

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    Utilizing the Two Micron All Sky Survey (2MASS) Second Incremental Data Release Catalog, we have retrieved near-IR magnitudes for several hundred hot subdwarfs (sdO and sdB stars) drawn from the "Catalogue of Spectroscopically Identified Hot Subdwarfs" (Kilkenny, Heber, & Drilling 1988, 1992). This sample size greatly exceeds that of previous studies of hot subdwarfs. Examining 2MASS photometry alone or in combination with visual photometry (Johnson BV or Stromgren uvby) available in the literature, we show that it is possible to identify hot subdwarf stars that exhibit atypically red IR colors that can be attributed to the presence of an unresolved late type companion. Utilizing this large sample, we attempt for the first time to define an approximately volume limited sample of hot subdwarfs. We discuss the considerations, biases, and difficulties in defining such a sample. We find that, of the hot subdwarfs in Kilkenny et al., about 40% in a magnitude limited sample have colors that are consistent with the presence of an unresolved late type companion. Binary stars are over-represented in a magnitude limited sample. In an approximately volume limited sample the fraction of composite-color binaries is about 30%.Comment: to appear in Sept 2003 AJ, 41 pages total, 12 figures, 2 tables are truncated (full tables to appear in electronic journal or available by request

    The rate of brain abnormalities on in utero MRI studies in fetuses with normal ultrasound examinations of the brain and calculation of indicators of diagnostic performance

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    AIM To estimate the rate of unexpected brain abnormalities detected by in utero magnetic resonance imaging (iuMRI) in fetuses without abnormalities at ultrasonography (USS). MATERIALS AND METHODS A prospective cohort study of pregnant women whose fetus had no structural brain (or body) abnormalities recognised on antenatal ultrasonography. Women were recruited from 12 centres across the UK and underwent iuMRI at 18 gestational weeks or more in the [blinded for review]. The imaging studies were reviewed by an experienced neuroradiologist. The positive and negative predictive values of both USS and iuMRI have been calculated by combining the results of this study with the results from the main [blinded for review] study. RESULTS One hundred and ninety-eight pregnant women were recruited and underwent iuMRI of 205 fetuses. Brain abnormalities were shown on iuMRI in two fetuses that were not recognised on USS (one case of a focal cortical abnormality and one case of mild ventriculomegaly). The negative predictive value for USS was 99.5% and 100% for iuMRI. CONCLUSIONS To the authors' knowledge, this is the first study comparing USS and iuMRI in low-risk pregnancies. USS has a comparatively high rule-out for fetal brain abnormalities and should remain the screening tool of choice
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