698 research outputs found

    The Learning Library in Context: Community, Integration, and Influence

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    The learning library is a construct based on the sociocultural theories of Lev Vygotsky and Jean Lave. These theories hold that learning happens through social interaction, that learners move through increasingly complex zones of development through the assistance of more capable others, and that real learning is situated only in specific cultural environments. The learning library bases its programs and services on these ideas through programmatic partnerships with specific groups such as learning communities and cohorts of students; through curricular integration so that learning about information resources is situated within the daily life of the college or university; through using the library as a locus for, and facilitator of, sustained interactions among students, faculty, and librarians; and by using the social interactions developed among communities of learners to extend the influence of the library throughout the institution. This article examines how these facets of the learning library are reflected in four programmatic models at George Mason University's Johnson Center Library: the course-integrated model (New Century College, NCC), the course-related model (English 101: Composition), the orientation/peer advising model (University 100: University Life), and the information/term paper counseling and coaching model (partnership with the University's Writing Center, WC). © 2001 Elsevier Science Inc. All rights reserved.No embarg

    Generalizable Methods for Modeling Lumbar Spine Kinematics

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    A more complete understanding of lumbar spine kinematics could improve diagnoses and treatment of low back pathologies and may advance the development of biomechanical models. Kinematics describes motion of the five lumbar vertebrae without consideration for the forces that cause the motion. Despite considerable attention from researchers and clinicians, lumbar spine kinematics are not fully understood because the anatomy is not accessible for direct observation and the complex governing biomechanics produce small magnitude, coupled intervertebral movements. The overall goal of this project was to develop a descriptive model of intervertebral lumbar spine kinematics that is applicable to a generalizable subject population with diverse anthropometry. To accomplish this, a method was developed for measuring three-dimensional vertebral configuration using positional magnetic resonance imaging (MRI). The method makes use of automated vertebral registration to address time limitations in current data processing techniques and improves the ability to power experimental investigations. Finally, a geometric model of lumbar vertebral kinematics was developed using principal component regression applied to in vivo vertebral measurement data across the range of flexion and extension joint motion. This principal component-based approach offers unique advantages for predicting and interpreting performance of complex systems such as lumbar joint biomechanics because no assumptions are made regarding the governing mechanisms. This provides an opportunity to infer mechanistic characteristics about intervertebral joint kinematics and to use in vivo data to validate musculoskeletal models

    Directly interrogating single quantum dot labelled UvrA2 molecules on DNA tightropes using an optically trapped nanoprobe

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    AbstractIn this study we describe a new methodology to physically probe individual complexes formed between proteins and DNA. By combining nanoscale, high speed physical force measurement with sensitive fluorescence imaging we investigate the complex formed between the prokaryotic DNA repair protein UvrA2 and DNA. This approach uses a triangular, optically-trapped “nanoprobe” with a nanometer scale tip protruding from one vertex. By scanning this tip along a single DNA strand suspended between surface-bound micron-scale beads, quantum-dot tagged UvrA2 molecules bound to these ‘”DNA tightropes” can be mechanically interrogated. Encounters with UvrA2 led to deflections of the whole nanoprobe structure, which were converted to resistive force. A force histogram from all 144 detected interactions generated a bimodal distribution centered on 2.6 and 8.1 pN, possibly reflecting the asymmetry of UvrA2’s binding to DNA. These observations successfully demonstrate the use of a highly controllable purpose-designed and built synthetic nanoprobe combined with fluorescence imaging to study protein-DNA interactions at the single molecule level.</jats:p

    The Ursinus Weekly, October 12, 1964

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    Thespians choose Blore & Rodimer, Fall cast leads: Write me a murder heads into first stage of production • Pledging begins as sororities end last week of rushing: 61 women sign bids • Queen Jeanne Dawson, grid triumph, flavor weekend fun: Returning alumni enjoy cold day\u27s festivities • Lancaster theologian speaking tonight on Vatican Council II • Pre-meds hear members, list season speakers • Peace Corps worker to speak here • Y adds new concept to traditional retreat format: Fernbrook site of weekend\u27s activities • Editorial: Apathy or futility • Green poncho raincoats become UC fetish • UC students see touring Goldwater • Democrats meet the candidates • Young Republicans hold first caucus • Kaffee Klatch drafts variety • Human Relations Club begins work • Bears eat-up Blue Jays 38-22, exciting second half: Degenhardt wins Walker Memorial • Beta Sig, Seals lead leagues • Soccer team ties East Baptist, 2-2 • UC soccer team outplays alumni • J.V. hockey team victorious in first two season games: Crush Gwynedd 6-1, line scores at will; Defense stalwart defeat tough Penn • Answers and questions • Dear Ursala: advice column • Greek gleaningshttps://digitalcommons.ursinus.edu/weekly/1229/thumbnail.jp

    Predominant Asymmetrical Stem Cell Fate Outcome Limits the Rate of Niche Succession in Human Colonic Crypts.

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    Stem cell (SC) dynamics within the human colorectal crypt SC niche remain poorly understood, with previous studies proposing divergent hypotheses on the predominant mode of SC self-renewal and the rate of SC replacement. Here we use age-related mitochondrial oxidative phosphorylation (OXPHOS) defects to trace clonal lineages within human colorectal crypts across the adult life-course. By resolving the frequency and size distribution of OXPHOS-deficient clones, quantitative analysis shows that, in common with mouse, long-term maintenance of the colonic epithelial crypt relies on stochastic SC loss and replacement mediated by competition for limited niche access. We find that the colonic crypt is maintained by ~5 effective SCs. However, with a SC loss/replacement rate estimated to be slower than once per year, our results indicate that the vast majority of individual SC divisions result in asymmetric fate outcome. These findings provide a quantitative platform to detect and study deviations from human colorectal crypt SC niche homeostasis during the process of colorectal carcinogenesis.Wellcome Trus

    Recruitment of UvrBC complexes to UV-induced damage in the absence of UvrA increases cell survival

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    Nucleotide excision repair (NER) is the primary mechanism for removal of ultraviolet light (UV)-induced DNA photoproducts and is mechanistically conserved across all kingdoms of life. Bacterial NER involves damage recognition by UvrA2 and UvrB, followed by UvrC-mediated incision either side of the lesion. Here, using a combination of in vitro and in vivo single-molecule studies we show that a UvrBC complex is capable of lesion identification in the absence of UvrA. Single-molecule analysis of eGFP-labelled UvrB and UvrC in living cells showed that UV damage caused these proteins to switch from cytoplasmic diffusion to stable complexes on DNA. Surprisingly, ectopic expression of UvrC in a uvrA deleted strain increased UV survival. These data provide evidence for a previously unrealized mechanism of survival that can occur through direct lesion recognition by a UvrBC complex

    Real-time single-molecule imaging reveals a direct interaction between UvrC and UvrB on DNA tightropes

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    Nucleotide excision DNA repair is mechanistically conserved across all kingdoms of life. In prokaryotes, this multi-enzyme process requires six proteins: UvrA?D, DNA polymerase I and DNA ligase. To examine how UvrC locates the UvrB? DNA pre-incision complex at a site of damage, we have labeled UvrB and UvrC with different colored quantum dots and quantitatively observed their interactions with DNA tightropes under a variety of solution conditions using oblique angle fluorescence imaging. Alone, UvrC predominantly interacts statically with DNA at low salt. Surprisingly, however, UvrC and UvrB together in solution bind to form the previously unseen UvrBC complex on duplex DNA. This UvrBC complex is highly motile and engages in unbiased one-dimensional diffusion. To test whether UvrB makes direct contact with the DNA in the UvrBC?DNA complex, we investigated three UvrB mutants: Y96A, a b-hairpin deletion and D338N. These mutants affected the motile properties of the UvrBC complex, indicating that UvrB is in intimate contact with the DNA when bound to UvrC. Given the in vivo excess of UvrB and the abundance of UvrBC in our experiments, this newly identified complex is likely to be the predominant form of UvrC in the cell. © 2013 The Author(s)

    Making a home, finding a job: investigating early housing and employment outcomes for young people leaving care

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    This paper presents findings from a new study of outcomes for young people leaving care funded by the Department for Education and Skills. It reports findings for a sample of 106 young people in relation to progress made in housing and employment some 12-15 months after leaving care. The generally poor employment outcomes of care leavers are acknowledged, but ingredients that make for success are also highlighted, including the value of settled care and post-care careers, sound career planning and, significantly, the value of delaying young people's transitions from care. Early career paths also interconnect with how young people fare in housing, in developing life skills and with other problems in their lives after leaving care. Housing outcomes were more encouraging and predominantly shaped by events after leaving care, and faring well in housing was the factor most closely associated with positive mental well-being in young people. Some groups that are at risk of faring badly are identified, including young people with mental-health problems, young people with persistent offending or substance misuse problems and, in some respects, young disabled people. The implications of these findings for leaving care services are considered

    Hereditary angioedema: beyond international consensus - circa December 2010 - The Canadian Society of Allergy and Clinical Immunology Dr. David McCourtie Lecture

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    <p>Abstract</p> <p>Background</p> <p>The 2010 International Consensus Algorithm for the Diagnosis, Therapy and Management of Hereditary Angioedema was published earlier this year in this Journal (Bowen et al. <it>Allergy, Asthma & Clinical Immunology </it>2010, 6:24 - <url>http://www.aacijournal.com/content/6/1/24</url>). Since that publication, there have been multiple phase III clinical trials published on either prophylaxis or therapy of hereditary angioedema and some of these products have changed approval status in various countries. This manuscript was prepared to review and update the management of hereditary angioedema.</p> <p>Objective</p> <p>To review approaches for the diagnosis and management of hereditary angioedema (HAE) circa December 2010 and present thoughts on moving from HAE management from international evidence-based consensus to facilitate more local health unit considerations balancing costs, efficacies of treatments, and risk benefits. Thoughts will reflect Canadian and international experiences.</p> <p>Methods</p> <p>PubMed searches including hereditary angioedema and diagnosis, therapy, management and consensus were reviewed as well as press releases from various pharmaceutical companies to early December 2010.</p> <p>Results</p> <p>The 2010 International Consensus Algorithms for the Diagnosis, Therapy and Management of Hereditary Angioedema is reviewed in light of the newly published phase III Clinical trials for prevention and therapy of HAE. Management approaches and models are discussed.</p> <p>Conclusions</p> <p>Consensus approach and double-blind placebo controlled trials are only interim guides to a complex disorder such as HAE and should be replaced as soon as possible with large phase IV clinical trials, meta analyses, data base registry validation of approaches including quality of life and cost benefit analyses, safety, and head-to-head clinical trials investigating superiority or non-inferiority comparisons of available approaches. Since not all therapeutic products are available in all jurisdictions and since health care delivery approaches and philosophy vary between countries, each health care delivery sector will likely devise their own algorithms based on local practicalities for implementing evidence-based guidelines and standards for HAE disease management. Quality-of-life and cost affordability benefit conclusions will likely vary between countries and health care units. Data base registries for rare disorders like HAE should be used to detect early adverse events for new therapies and to facilitate phase IV clinical trials and encourage superiority and non-inferiority comparisons of HAE management approaches.</p

    Comparison of observed and model-computed low frequency circulation and hydrography on the New England Shelf

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    Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): C09015, doi:10.1029/2007JC004394.The finite volume coastal ocean model (FVCOM) is configured to study the interannual variability of circulation in the Gulf of Maine (GoM) and Georges Bank. The FVCOM-GoM system incorporates realistic time-dependent surface forcing derived from a high-resolution mesoscale meteorological model (MM5) and assimilation of observed quantities including sea surface temperature and salinity and temperature fields on the open boundary. An evaluation of FVCOM-GoM model skill on the New England shelf is made by comparison of computed fields and data collected during the Coastal Mixing and Optics (CMO) Program (August 1996–June 1997). Model mean currents for the full CMO period compare well in both magnitude and direction in fall and winter but overpredict the westward flow in spring. The direction and ellipticity of the subtidal variability correspond but computed magnitudes are around 20% below observed, partially due to underprediction of the variability by MM5. Response of subtidal currents to wind-forcing shows the model captures the directional dependence, as well as seasonal variability of the lag. Hydrographic results show that FVCOM-GoM resolves the spatial and temporal evolution of the temperature and salinity fields. The model-computed surface salinity field compares well, except in May when there is no indication of the fresh surface layer from the Connecticut River discharge noted in the observations. Analysis of model-computed results indicates that the plume was unable to extend to the mooring location due to the presence of a westward mean model-computed flow during that time that was stronger than observed. Overall FVCOM-GoM captures well the dynamics of the mean and subtidal flow on the New England shelf.G. Cowles was supported by the Massachusetts Marine Fisheries Institute (MFI) through NOAA grants DOC/NOAA/ NA04NMF4720332 and DOC/NOAA/NA05NMF4721131, S. Lentz by the NSF Ocean Sciences Division through grants OCE-841292 and OCE- 848961, C. Chen and Q. Xu through the NSF/NOAA GLOBEC/Northwest Atlantic/Georges Bank Program under NSF grants OCE-0234545 and OCE-0227679 and NOAA grants NA-16OP2323, and R. Beardsley through NOAA grant NA-17RJ1223
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