6,307 research outputs found

    Three Centuries on the South Campus

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    (Reprinted from La Salle: A Quarterly La Salle University Magazine, Fall 1998) The story of the south campus begins, as any settlement of a new country must, with the land itself. Early in the eighteenth century, the horseback rider exploring his 500-acre plantation acutely felt what we in our cars scarcely notice: La Salle’s property, approached from the south, rises as a formidable hill. And the rider observed, as we no longer can, two pristine and swift-moving creeks--one following the line of present-day Belfield Avenue and the other that of Ogontz Avenue.https://digitalcommons.lasalle.edu/essays/1003/thumbnail.jp

    The Remarkable Wisters at Belfield

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    Reprinted from La Salle: A Quarterly La Salle University Magazine, Spring 1994 The history of the nineteenth-century Wisters at Belfield encompasses three adjoining properties--and begins (perhaps appropriately for a future university campus) with a teenager who defied her father.https://digitalcommons.lasalle.edu/essays/1001/thumbnail.jp

    Development of polyisocyanurate pour foam formulation for space shuttle external tank thermal protection system

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    Four commercially available polyisocyanurate polyurethane spray-foam insulation formulations are used to coat the external tank of the space shuttle. There are several problems associated with these formulations. For example, some do not perform well as pourable closeout/repair systems. Some do not perform well at cryogenic temperatures (poor adhesion to aluminum at liquid nitrogen temperatures). Their thermal stability at elevated temperatures is not adequate. A major defect in all the systems is the lack of detailed chemical information. The formulations are simply supplied to NASA and Martin Marietta, the primary contractor, as components; Part A (isocyanate) and Part B (poly(s) and additives). Because of the lack of chemical information the performance behavior data for the current system, NASA sought the development of a non-proprietary room temperature curable foam insulation. Requirements for the developed system were that it should exhibit equal or better thermal stability both at elevated and cryogenic temperatures with better adhesion to aluminum as compared to the current system. Several formulations were developed that met these requirements, i.e., thermal stability, good pourability, and good bonding to aluminum

    Less government intervention in biodiversity management: risks and opportunities

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    n a changing global environment, with increasing pressure on ecosystem goods and services, biodiversity conservation is likely to become increasingly important. However, with the current global financial crisis, governments are increasingly trying to stabilise economies through spending cuts aiming to reduce national deficits. Within such an economic climate, the devolution of governance through public participation is an intrinsically appealing concept. We outline a number of challenges that explain why increased participation in biodiversity management has been and may continue to be problematic. Using as a case study the local stakeholder-driven Moray Firth Seal Management Plan in Scotland, we identify four key conditions that were crucial to the successful participatory management of a biodiversity conflict: a local champion, the emergence of a crisis point, the involvement of decision-makers, and long-term financial and institutional support. Three of the four conditions point to the role of direct government involvement, highlighting the risk of devolving responsibility for biodiversity conflict management to local communities. We argue that without an informed debate, the move towards a more participatory approach could pose a danger to hard-won policy gains in relation to public participation, biodiversity conservation and conflict management

    Deriving Iodine-free spectra for high-resolution echelle spectrographs

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    We describe a new method to derive clean, iodine-free spectra directly from observations acquired using high-resolution echelle spectrographs equipped with iodine cells. The main motivation to obtain iodine-free spectra is to use portions of the spectrum that are superimposed with the dense forest of iodine absorption lines, in order to retrieve lines that can be used to monitor the magnetic activity of the star, helping to validate candidate planets. In short, we provide a straight-forward methodology to clean the spectra by using the forward model used to derive radial velocities, the Line Spread Function information plus the stellar spectrum without iodine to reconstruct and subtract the iodine spectrum from the observations. We show our results using observations of the star τ\tau Ceti acquired with the PFS, HIRES and UCLES spectrographs, reaching an iodine-free spectrum correction at the ∼\sim1% RMS level. We additionally discuss the limitations and further applications of the method.Comment: 15 pages, 7 figures. Accepted for publication in A

    Interview of James A. Butler, Ph.D.

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    James A. Butler was born in 1945 in Wilkinsburg, Pennsylvania. After graduating from Central Catholic High School in Pittsburgh, Pennsylvania, he attended La Salle College, graduating in 1967. He received his Ph.D. from Cornell University and was hired to teach in the English Department of La Salle University. He has been English Department Chair, Director of the Honors Program, and Curator of the Wister Special Collection in Connelly Library. He is a Wordsworth specialist

    Crossing the Brown Dwarf Desert Using Adaptive Optics: A Very Close L-Dwarf Companion to the Nearby Solar Analog HR 7672

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    We have found a very faint companion to the active solar analog HR 7672 (HD 190406; GJ 779; 15 Sge). Three epochs of high resolution imaging using adaptive optics (AO) at the Gemini-North and Keck II Telescopes demonstrate that HR 7672B is a common proper motion companion, with a separation of 0.79" (14 AU) and a 2.16 um flux ratio of 8.6 mags. Using follow-up K-band spectroscopy from Keck AO+NIRSPEC, we measure a spectral type of L4.5+/-1.5. This is the closest ultracool companion around a main sequence star found to date by direct imaging. We estimate the primary has an age of 1-3 Gyr. Assuming coevality, the companion is most likely substellar, with a mass of 55-78 Mjup based on theoretical models. The primary star shows a long-term radial velocity trend, and we combine the radial velocity data and AO imaging to set a firm (model-independent) lower limit of 48 Mjup. In contrast to the paucity of brown dwarf companions at <~4 AU around FGK dwarfs, HR 7672B implies that brown dwarf companions do exist at separations comparable to those of the giant planets in our own solar system. Its presence is at variance with scenarios where brown dwarfs form as ejected stellar embryos. Moreover, since HR 7672B is likely too massive to have formed in a circumstellar disk as planets are believed to, its discovery suggests that a diversity of physical processes act to populate the outer regions of exoplanetary systems.Comment: Astrophysical Journal, in pres

    Metal-ligand interplay in strongly-correlated oxides: a parametrized phase diagram for pressure induced spin transitions

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    We investigate the magnetic properties of archetypal transition-metal oxides MnO, FeO, CoO and NiO under very high pressure by x-ray emission spectroscopy at the K\beta line. We observe a strong modification of the magnetism in the megabar range in all the samples except NiO. The results are analyzed within a multiplet approach including charge-transfer effects. The pressure dependence of the emission line is well accounted for by changes of the ligand field acting on the d electrons and allows us to extract parameters like local d-hybridization strength, O-2p bandwidth and ionic crystal field across the magnetic transition. This approach allows a first-hand insight into the mechanism of the pressure induced spin transition.Comment: 5 pages, 3 figure

    Charles Willson Peale\u27s Belfield : A History of a National Historic Landmark, 1684-1984

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    From the Preface: Artist, inventor, museum-keeper, naturalist, and polymath, Philadelphian Charles Willson Peale may not have been in a league of his own because of his achievements in so many diverse fields , but fellow members of that league of colonial overachievers would include such luminaries as Benjamin Franklin, George Washington, and Thomas Jefferson. (Peale painted all three, and from Belfield Peale conducted an extensive correspondence with Jefferson at Monticello.) Any home of people such as these would be of interest; moreover, Peale in his Belfield years self-consciously fashioned a land cape to express his personality. The account of Peale in this booklet aim at (1) recreating the life he lived in these Belfield surroundings; and (2) interpreting the significance of what remains. Both before and after Peale, Belfield also has a rich and captivating history. Slaveholders, abolitionists, miss ionaries, members of a celibate and utopian community, refugees from revolution , farmers, industrialists, soldiers in most of the country\u27 wars, civic leaders, writers, many individualists, some academics, and more than a few eccentrics: the story of America finds an echo in this account of Belfield and its inhabitants.https://digitalcommons.lasalle.edu/belfield_books/1000/thumbnail.jp
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