306 research outputs found

    A study of the record and report forms in twenty-five junior high schools of Kansas, 1927

    Get PDF
    Thesis (M.S.Ed.)--University of Kansas, Education, 1929

    Evidence of a discontinuous disk structure around the Herbig Ae star HD 139 614

    Full text link
    A new class of pre-main sequence objects has been recently identified as pre-transitional disks. They present near-infrared excess coupled to a flux deficit at about 10 microns and a rising mid-infrared and far-infrared spectrum. These features suggest a disk structure with inner and outer dust components, separated by a dust-depleted region (or gap). We here report on the first interferometric observations of the disk around the Herbig Ae star HD 139614. Its infrared spectrum suggests a flared disk, and presents pre-transitional features,namely a substantial near-infrared excess accompanied by a dip around 6 microns and a rising mid-infrared part. In this framework, we performed a study of the spectral energy distribution (SED) and the mid-infrared VLTI/MIDI interferometric data to constrain thespatial structure of the inner dust disk region and assess its possibly multi-component structure. We based our work on a temperature-gradient disk model that includes dust opacity. While we could not reproduce the SED and interferometric visibilities with a one-component disk, a better agreement was obtained with a two-component disk model composed of an optically thin inner disk extending from 0.22 to 2.3 au, a gap, and an outer temperature-gradient disk starting at 5.6 au. Therefore, our modeling favors an extended and optically thin inner dust component and in principle rules out the possibility that the near-infrared excess originates only from a spatially confined region. Moreover, the outer disk is characterized by a very steep temperature profile and a temperature higher than 300 K at its inner edge. This suggests the existence of a warm component corresponding to a scenario where the inner edge of the outer disk is directly illuminated by the central star. This is an expected consequence of the presence of a gap, thus indicative of a pre-transitional structure.Comment: 14 pages, 6 figure

    HD139614: the interferometric case for a group-Ib pre-transitional young disk

    Get PDF
    The Herbig Ae star HD 139614 is a group-Ib object, which featureless SED indicates disk flaring and a possible pre-transitional evolutionary stage. We present mid- and near-IR interferometric results collected with MIDI, AMBER and PIONIER with the aim of constraining the spatial structure of the 0.1-10 AU disk region and assess its possible multi-component structure. A two-component disk model composed of an optically thin 2-AU wide inner disk and an outer temperature-gradient disk starting at 5.6 AU reproduces well the observations. This is an additional argument to the idea that group-I HAeBe inner disks could be already in the disk-clearing transient stage. HD 139614 will become a prime target for mid-IR interferometric imaging with the second-generation instrument MATISSE of the VLTI.Comment: SPIE Astronomical Telescopes and Instrumentation conference, June 2014, 11 pages, 7 Figure

    Effect Of Coronary Bypass And Valve Structure On Outcome In Isolated Valve Replacement For Aortic Stenosis

    Get PDF
    Reports differ regarding the effect of concomitant coronary artery bypass grafting (CABG) in patients who undergo aortic valve replacement (AVR) for aortic stenosis (AS), and no reports have described the effect of aortic valve structure in patients who undergo AVR for AS. A total of 871 patients aged 24 to 94 years (mean 70) whose AVR for AS was their first cardiac operation, with or without first concomitant CABG, were included. Patients who underwent mitral valve procedures were excluded. In comparison with the 443 patients (51%) who did not undergo CABG, the 428 (49%) who underwent concomitant CABG were significantly older, were more often male, had lower transvalvular peak systolic pressure gradients and larger valve areas, had lower frequencies of congenitally malformed aortic valves, had lighter valves by weight, had higher frequencies of systemic hypertension, and had longer stays in the hospital after AVR. Early and late (to 10 years) mortality were similar by propensity-adjusted analysis in patients who did and did not undergo concomitant CABG. Congenitally unicuspid or bicuspid valves occurred in approximately 90% of those aged 21 to 50, in nearly 70% in those aged 51 to 70 years, and in just over 30% in those aged 71 to 95 years. Unadjusted and adjusted survival was significantly higher in patients with unicuspid or bicuspid valves compared to those with tricuspid valves. In conclusion, although concomitant CABG had no effect on the adjusted probability of survival, the type of aortic valve (unicuspid or bicuspid vs tricuspid) significantly affected the unadjusted and adjusted probability of survival. (C) 2012 Elsevier Inc. All rights reserved. (Am J Cardiol 2012;109:1334-1340)Statistic

    Parasitic Interference in Long Baseline Optical Interferometry: Requirements for Hot Jupiter-like Planet Detection

    No full text
    International audienceThe observable quantities in optical interferometry, which are the modulus and the phase of the complex visibility, may be corrupted by parasitic fringes superimposed on the genuine fringe pattern. These fringes are due to an interference phenomenon occurring from stray light effects inside an interferometric instrument. We developed an analytical approach to better understand this phenomenon when stray light causes cross talk between beams. We deduced that the parasitic interference significantly affects the interferometric phase and thus the associated observables including the differential phase and the closure phase. The amount of parasitic flux coupled to the piston between beams appears to be very influential in this degradation. For instance, considering a point-like source and a piston ranging from λ/500 to λ/5 in the L band (λ = 3.5 μm), a parasitic flux of about 1% of the total flux produces a parasitic phase reaching at most one-third of the intrinsic phase. The piston, which can have different origins (instrumental stability, atmospheric perturbations, etc.), thus amplifies the effect of parasitic interference. According to the specifications of piston correction in space or at ground level (respectively λ/500 ≈ 2 nm and λ/30 ≈ 100 nm), the detection of hot Jupiter-like planets, one of the most challenging aims for current ground-based interferometers, limits parasitic radiation to about 5% of the incident intensity. This was evaluated by considering different types of hot Jupiter synthetic spectra. Otherwise, if no fringe tracking is used, the detection of a typical hot Jupiter-like system with a solar-like star would admit a maximum level of parasitic intensity of 0.01% for piston errors equal to λ/15. If the fringe tracking specifications are not precisely observed, it thus appears that the allowed level of parasitic intensity dramatically decreases and may prevent the detection. In parallel, the calibration of the parasitic phase by a reference star, at this accuracy level, seems very difficult. Moreover, since parasitic phase is an object-dependent quantity, the use of a hypothetical phase abacus, directly giving the parasitic phase from a given parasitic flux level, is also impossible. Some instrumental solutions, implemented at the instrument design stage for limiting or preventing this parasitic interference, appear to be crucial and are presented in this paper

    Tailoring exciton diffusion and domain size in photovoltaic small molecules by processing

    Get PDF
    Funding: European Research Council (grant 321305); UK EPSRC for equipment grant (EP/L017008/1) and (EP/M508214/1) (OB).Exciton diffusion is an important part of light harvesting in organic photovoltaics (OPVs) because it enables excitons to reach the interface betweeen donor and acceptor and contribute to the photocurrent. Here we used simple and cost-effective techniques of thermal annealing and solvent vapour annealing to increase the exciton diffusion coefficient and exciton diffusion length in two liquid crystalline electron donor materials BQR and BTR. We found that the three-dimensional exciton diffusion length increased to ~40 nm upon annealing in both materials. Grazing-incidence wide angle X-ray scattering (GIWAXS) measurements show an increase of crystallite size to ~37 nm in both materials after thermal annealing. We determined an average domain size of these materials in the blends with PC71BM using diffusion-limited fluorescence quenching and found that it increased to 31 nm in BTR PC71BM blends and to 60 nm in BQR PC71BM blends. Our results provide understanding of how annealing improves device efficiency.PostprintPeer reviewe

    Strong coupling in a microcavity containing β-carotene

    Get PDF
    © 2018 Optical Society of America. Abstract: We have fabricated an open-cavity microcavity structure containing a thin film of the biologically-derived molecule β-carotene. We show that the β-carotene absorption can be described in terms of a series of Lorentzian functions that approximate the 0-0, 0-1, 0-2, 0-3 and 0-4 electronic and vibronic transitions. On placing this molecular material into a microcavity, we obtain anti-crossing between the cavity mode and the 0-1 vibronic transition, however other electronic and vibronic transitions remain in the intermediate or weak-coupling regime due to their lower oscillator strength and broader linewidth. We discuss the consequences of strong-coupling for the possible modification of photosynthetic processes, or a re-ordering of allowed and optically-forbidden states

    Paradoxical Association of Enhanced Cholesterol Efflux With Increased Incident Cardiovascular Risks

    Get PDF
    Objective—Diminished cholesterol efflux activity of apolipoprotein B (apoB)–depleted serum is associated with prevalent coronary artery disease, but its prognostic value for incident cardiovascular events is unclear. We investigated the relationship of cholesterol efflux activity with both prevalent coronary artery disease and incident development of major adverse cardiovascular events (death, myocardial infarction, or stroke). Approach and Results—Cholesterol efflux activity from free cholesterol–enriched macrophages was measured in 2 case–control cohorts: (1) an angiographic cohort (n=1150) comprising stable subjects undergoing elective diagnostic coronary angiography and (2) an outpatient cohort (n=577). Analysis of media from cholesterol efflux assays revealed that the high-density lipoprotein fraction (1.06

    The Treasured Hunt: Collecting Medieval and Renaissance Manuscripts, Past, Present, and Future

    Get PDF
    Welcome and Opening Remarks: E. Ann Matter, University of Pennsylvania, and Lynn Ransom, Free Library of Philadelphia Session 1. Beginnings: Collecting in the Middle Ages and Renaissance Session Chair: Emily Steiner, Department of English, University of Pennsylvania Claire Richter Sherman, Center for Advanced Study in the Visual Arts at the National Gallery of Art, The Manuscript Collection of King Charles V of France: The Personal and the Political David Rundle, History Faculty and Corpus Christi College, Oxford University, The Butcher of England and the Renaissance Arts of Book-Collecting Session 2: Civic Service: The Legacies of Philadelphia-Area Collectors Chair: Peter Stallybrass, Department of English, University of Pennsylvania James Tanis, Director of Libraries and Professor of History Emeritus, Bryn Mawr College, Migrating Manuscripts Derick Dreher, Director, The Rosenbach Museum & Library, Of Private Collectors and Public Libraries: Dr. A. S. W. Rosenbach and John Frederick Lewis Session 3: Keynote address Welcome: H. Carton Rogers, Vice Provost & Director of Libraries, University of Pennsylvania Chair: Robert Maxwell, Department of the History of Art, University of Pennsylvania Christopher de Hamel, Gaylord Donnelley Fellow Librarian, Corpus Christi College, Cambridge University, The Manuscript Collection of C. L. Ricketts (1859-1941) Session 4: The Hunters and the Hunted: A Roundtable Discussion with Private and Institutional Collectors Chair: David Wallace, Department of English, University of Pennsylvania Moderator: Richard Linenthal, Bernard Quaritch Ltd. Panelists: Lawrence J. Schoenberg, Private Collector Gifford Combs, Private Collector Toshiyuki Takamiya, Private Collector, Keio University Consuelo Dutschke, Curator of Medieval and Renaissance Manuscripts, Columbia University William Noel, Curator of Manuscripts and Rare Books, The Walters Art Museu
    corecore