457 research outputs found

    Conformational studies of the beta amyloid protein and in vitro models for the effects of apolipoprotein E on fibril formation in Alzheimer's disease

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1996.Includes bibliographical references.by Krista Carole Evans.Ph.D

    Exploration Challenges: Transferring Ground Repair Techniques to Space Flight Application

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    Fulfilling NASA's Vision for Space Exploration will demand an extended presence in space at distances from our home planet that exceed our current experience in space logistics and maintenance. The ability to perform repairs in lieu of the customary Orbital Replacement Unit (ORU) process where a faulty part is replaced will be elevated from contingency to routine to sustain operations. The use and cost effectiveness of field repairs for ground based operations in industry and the military have advanced with the development of technology in new materials, new repair techniques and new equipment. The unique environments, accessibility constraints and Extra Vehicular Activity (EVA) issues of space operations will require extensive assessment and evolution of these technologies to provide an equivalent and expected level of assurance to mission success. Challenges include the necessity of changes in design philosophy and policy, extremes in thermal cycling, disruptive forces (such as static charge and wind entrainment) on developed methods for control of materials, dramatically increased volatility of chemicals for cleaning and other compounds due to extremely low pressures, the limits imposed on dexterity and maneuverability by current EVA equipment and practices, and the necessity of unique verification methodology. This paper describes these challenges in and discusses the effects on the established ground techniques for repair. The paper also describes the leading repair methodology candidates and their beneficial attributes for resolving these issues with the evolution of technology

    A large-scale inheritance-based morphological lexicon for Russian

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    In this paper we describe the mapping of Zaliznjak’s (1977) morphological classes into the lexical representation language DATR (Evans and Gazdar 1996). On the basis of the resulting DATR theory a set of fully inflected forms together with their as-sociated morphosyntax can automatically be generated from the electronic version of Zaliznjak’s dictionary (Ilola and Mustajoki 1989). From this data we plan to develop a wide-coverage morphosyntactic lemma-tizer and tagger for Russian

    The use of high aspect ratio photoresist (SU-8) for super-hydrophobic pattern prototyping

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    In this work we present a reliable technique for the production of large areas of high aspect-ratio patterns and describe their use as model super-hydrophobic systems. The high thickness and straight sidewalls possible with SU-8 were used to generate dense patterns of small pillars. These photoresist patterns could be used directly, without the need for micromoulding. A method is given allowing resist thickness to be varied over a wide range and a bottom antireflective layer was used to simplify patterning on reflective substrates. This patterning technique allows rapid testing of wetting theories, as pattern size and depth can be varied simply and samples can be produced in sufficient numbers for laboratory use. We show how the static contact angle of water varies with pattern height for one sample-pattern and how static and dynamic contact angles vary with dimension using high aspect-ratio patterns

    Evidence gathering in support of sustainable Scottish inshore fisheries: work package (6) final report: integrating stock management considerations with market opportunities in the Scottish inshore fisheries sector – a pilot study

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    In June 2014, Hambrey Consulting successfully responded to a call for tenders for research to undertake a pilot assessment of the potential economic and associated benefits of establishing minimum market landing size (MMLS) in excess of minimum legal landing size (MLS) for shellfish; and to evaluate if such an intervention could be undertaken at a regional level. The project was originally conceived as including 3 case studies, but the scope of the research led us to focus mainly on the trawl and creel fishery for Nephrops prosecuted by the fleet based in Skye and SW Ross. The basic framework for the assessment approach was to: Develop an economic profile of the case study area and its fishing fleet; Review and synthesise existing data on size profile of the catch, the factors that affect size, including costs associated with individual (vessel) actions or strategies to increase the size profile of the catch; Analyse market and market trends, and the prices for different sizes of product; Develop economic models of representative fishing enterprises, taking account of the relationships between costs and returns and the size profile of the catch; Use plausible scenarios to explore likely short term economic consequences of any changes in MMLS; Use yield and utility per recruit analysis to explore possible yield benefits associated with increased MMLS.Publisher PD

    A Deep Chandra ACIS Study of NGC 4151. II. The Innermost Emission Line Region and Strong Evidence for Radio Jet-NLR Cloud Collision

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    We have studied the X-ray emission within the inner 150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of OVII, OVIII, and NeIX. These maps show extended structures that are spatially correlated with the radio outflow and optical [OIII] emission. We find strong evidence for jet--gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [FeII] emission, and optical clouds. In these regions, moreover, we find evidence of elevated NeIX/OVII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that >0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circum-nuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe Kalpha emission is <5% of the total, in disagreement with a previous claim that 65% of the Fe Kalpha emission originates in the extended narrow line region.Comment: Accepted for publication in ApJ. 28 pages, 9 figure

    The Grizzly, March 4, 1983

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    Zeta Chi Suspended: Fraternity Disciplined for Pledging Violations • Symposium Topics Discussed • New Forum Committee to Revise System • Letters to the Editor: Alumnus Responds to Grizzly Policy • Committee Reviews Appeals Procedure • Meistersingers Tour • Exam Schedule • Woodcuts at Myrin • Stravinsky Program Ends Winterfest • Lantern Deadline Approaches • Lewis on Wall Street • Alpha Sigma Nu Tops GPAs • Roving Reporter: The Administration is Proposing to put a Live-in Dean in 97 of New Men\u27s Dorm • Pre-Legal Society Resurrected • Swimmers Perform Beyond Expectation • Bear Blades Blaze to Victory • Gymnasts Draw No. 2 Ratinghttps://digitalcommons.ursinus.edu/grizzlynews/1096/thumbnail.jp

    The landscape of gifted and talented education in England and Wales: How are teachers implementing policy?

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    This is an Author's Accepted Manuscript of an article published in Research Papers in Education, 27(2), 167-186, 2012, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/02671522.2010.509514.This paper explores the evidence relating to how primary schools are responding to the ‘gifted and talented’ initiative in England and Wales. A questionnaire survey which invited both closed and open-ended responses was carried out with a national sample of primary schools. The survey indicated an increasing proportion of coordinators, compared with a survey carried out in 1996, were identifying their gifted and talented children as well as having associated school policies. However, the survey also highlighted a number of issues which need addressing if the initiative is to achieve its objective of providing the best possible educational opportunities for children. For example, it was found that a significant number of practitioners were not aware of the existence of the National Quality Standards for gifted and talented education, provided by the UK government in 2007, and the subject-specific criteria provided by the UK’s Curriculum Authority for identification and provision have been largely ignored. The process of identifying children to be placed on the ‘gifted and talented’ register seems haphazard and based on pragmatic reasons. Analysis of teachers’ responses also revealed a range of views and theoretical positioning held by them, which have implications for classroom practice. As the ‘gifted and talented’ initiative in the UK is entering a second decade, and yet more significant changes in policy are introduced, pertinent questions need to be raised and given consideration

    Morphological determinants of femoral strength in growth hormone-deficient transgenic growth-retarded (Tgr) rats

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    The extent to which childhood GHD affects adult fracture risk is unclear. We measured femoral strength in adult transgenic growth-retarded rats as a model of GHD. Long-term, moderate GHD was accompanied by endocrine and morphometric changes consistent with a significant reduction in femoral strength. Introduction: Childhood growth hormone deficiency (GHD) is associated with osteopenia, but little is known about its effects on subsequent adult bone strength and fracture risk. Materials and Methods: We have therefore measured femoral strength (failure load measured by three-point bending) in a new model of moderate GHD, the transgenic growth-retarded (Tgr) rat at 15, 22–23, and 52 weeks of age, and have quantified potential morphological and endocrine determinants of bone strength. Results: Skeletal growth retardation in Tgr rats was accompanied by a sustained reduction in the anterior-posterior diameter of the femoral cortex, whereas mid-diaphyseal cortical wall thicknesses were largely unaltered. Total femoral strength was significantly impaired in Tgr rats (p < 0.01), and this impairment was more pronounced in males than females. Compromised bone strength in Tgr rats could not be accounted for by the reduction in mechanical load (body weight) and was not caused by impairment of the material properties of the calcified tissue (ultimate tensile stress), despite marked reductions in femoral mineral density (areal bone mineral density; p < 0.001). Microcomputerized tomographical analysis revealed significant modification of the architecture of trabecular bone in Tgr rats, with reductions in the number and thickness of trabeculae (p < 0.05) and in the degree of anisotropy (p < 0.01). The marked reduction in plasma insulin-like growth factor-1 in Tgr rats was accompanied by the development of high circulating leptin levels (p < 0.01). Conclusion: These results show that the changes in endocrinology and bone morphology associated with long-term moderate GHD in Tgr rats are accompanied by changes consistent with a significant reduction in the threshold for femoral fracture
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