1,081 research outputs found

    Computing the endomorphism ring of an elliptic curve over a number field

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    We describe deterministic and probabilistic algorithms to determine whether or not a given monic irreducible polynomial H in Z[X] is a Hilbert class polynomial, and if so, which one. These algorithms can be used to determine whether a given algebraic integer is the j-invariant of an elliptic curve with complex multiplication (CM), and if so, the associated CM discriminant. More generally, given an elliptic curve E over a number field, one can use them to compute the endomorphism ring of E. Our algorithms admit simple implementations that are asymptotically and practically faster than existing approaches.Comment: updated and extended Table 1; 20 page

    Making a difference - the appropriate use of web technology

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    Much has been written elsewhere about how, different Information Technology tools, can in principle be used by groups or communities to make their web sites more effective for Continued Professional Development. In practice, complex use is not often the case. In particular, three sites were studied in Scotland, which provided web facilities for the over 60s. The sites, and the communities they served, used only simple Information Technology. Nevertheless, they enabled their communities to participate effectively, on the 'right side', of the European population's 'digital divide'

    Effects of treatment with antimicrobial agents on the human colonic microflora

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    Antimicrobial agents are the most valuable means available for treating bacterial infections. However, the administration of therapeutic doses of antimicrobial agents to patients is a leading cause of disturbance of the normal gastrointestinal microflora. This disturbance results in diminishing the natural defense mechanisms provided by the colonic microbial ecosystem, making the host vulnerable to infection by commensal microorganisms or nosocomial pathogens. In this minireview, the impacts of antimicrobials, individually and in combinations, on the human colonic microflora are discussed

    Bostonia. Volume 12

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    Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

    Abandon:World Picture Conference

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    Keynote by Laurence Rickels Live performance by Sandra Gibson and Luis Recoder The term abandon encompasses radical renunciation and immersive indulgence in its oscillation between abandonment of and abandonment to, between restraint and luxury, mindfulness and neglect. When we speak of abandonment we indicate a situation in which we take leave of something, or disband a collective entity, or else act in a way that suggests a disaggregation of certain protocols of behaviour, or belonging (as when we &#8216;laugh with abandon&#8217;). Discourses and scenes of media and politics are generally highly invested in ideas of taking-leave, breaking apart or away, acting with abandon. In the present moment, we believe the term resonates in manifold ways. For instance: with often painful choices between theoretical and political models that have outlasted their effectiveness but to which there seem to be no alternatives; with turns to abandoned objects as new sources of ontologies in which the turn itself is a mode of abandoning an established political-theoretical project; with the obdurate &#8216;problem&#8217; of pleasure in aesthetics and aesthetic theory as either the obstacle or the medium of the aesthetic’s interface with the political; with the cathexis of the body and its phenomenology as an instrument and medium of political and aesthetic experimentation; with attempts to relinquish the human, and its attendant association with agency, as a category of experience; with contemporary experiences/fantasies of control and resistance to control; with theatricalizations of abjuration and gratification.Abandon: World Picture Conference, conference, ICI Berlin, 7–8 November 2014 <https://doi.org/10.25620/e141107

    The ASPECTA toolkit : affordable Full Coverage Displays

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    Full Coverage Displays (FCDs) cover the interior surface of an entire room with pixels. FCDs make possible many new kinds of immersive display experiences - but current technology for building FCDs is expensive and complex, and software support for developing full-coverage applications is limited. To address these problems, we introduce ASPECTA, a hardware configuration and software toolkit that provide a low-cost and easy-to-use solution for creating full coverage systems. We outline ASPECTA’s (minimal) hardware requirements and describe the toolkit’s architecture, development API, server implementation, and configuration tool; we also provide a full example of how the toolkit can be used. We performed two evaluations of the toolkit: a case study of a research system built with ASPECTA, and a laboratory study that tested the effectiveness of the API. Our evaluations, as well as multiple examples of ASPECTA in use, show how ASPECTA can simplify configuration and development while still dramatically reducing the cost for creators of applications that take advantage of full-coverage displays.Postprin

    Surgical treatment of breast cancer among the elderly in the United States

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    BACKGROUND: Breast-conserving therapy (BCT) has emerged as the preferred treatment for most women with early stage breast cancer. However, there is concern for underuse in the elderly, with previously documented low rates of BCT and large variations in practice patterns. The authors' purpose was to examine patterns and correlates of BCT for breast cancer in the elderly US population. METHODS: The primary outcome was receipt of BCT. The 2003 to 2004 Medicare inpatient, outpatient, and carrier files were used to identify incident breast cancer patients and the American Medical Association to ascertain surgeon information. The primary independent variables were US state where treatment was performed along with patient and surgeon sociodemographic information. Multivariate logistic regression was used for the analyses. RESULTS: BCT was performed in 81.8% of patients (N = 20,032). Variation in use of BCT across states was low, ranging from 74.2% in Utah to 84.0% in New Mexico. Several factors were significantly associated with low use of BCT: advanced patient age (>85 vs 3 vs ≤3: OR, 0.26; 95% CI, 0.24-0.28), and low socioeconomic status (SES) (lowest quintile vs highest quintile SES: OR, 0.60; 95% CI, 0.52-0.68). Variation in use of BCT by surgeon was low, although female surgeons aged 40 to 49 years and ≥60 years had significantly higher use compared with younger men. CONCLUSIONS: BCT has become the primary management among elderly breast cancer patients. Despite earlier studies to the contrary, there is now little variation in BCT use among Medicare patients. Cancer 2011. © 2010 American Cancer Society.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83176/1/25617_ftp.pd

    On the semiclassical treatment of anharmonic quantum oscillators via coherent states - The Toda chain revisited

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    We use coherent states as a time-dependent variational ansatz for a semiclassical treatment of the dynamics of anharmonic quantum oscillators. In this approach the square variance of the Hamiltonian within coherent states is of particular interest. This quantity turns out to have natural interpretation with respect to time-dependent solutions of the semiclassical equations of motion. Moreover, our approach allows for an estimate of the decoherence time of a classical object due to quantum fluctuations. We illustrate our findings at the example of the Toda chain.Comment: 12 pages, some remarks added. Version to be published in J. Phys. A: Math. Ge

    Deoxyfluorination using CuF2 : enabled by a Lewis base activating group strategy

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    We thank the University of St Andrews for PhD studentships (D.E.S and S.C.), GlaxoSmithKline and the University of Glasgow for financial support.Deoxyfluorination is a primary method for the formation of C–F bonds. Bespoke reagents are commonly used due to issues associated with the low reactivity of metal fluorides. Here, we report the development of a simple strategy for deoxyfluorination using first‐row transition metal fluorides that overcomes these limitations. Using CuF2 as an exemplar, activation of an O ‐alkylisourea adduct formed in situ allows effective nucleophilic fluoride transfer to a range of primary and secondary alcohols. Spectroscopic investigations have been used to probe the origin of the enhanced reactivity of CuF2 . The utility of the process towards enabling 18F‐radiolabeling is also presented.PostprintPeer reviewe

    Late Pleistocene sediments, landforms and events in Scotland: a review of the terrestrial stratigraphic record

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    Lithostratigraphical studies coupled with the development of new dating methods has led to significant progress in understanding the Late Pleistocene terrestrial record in Scotland. Systematic analysis and re-evaluation of key localities have provided new insights into the complexity of the event stratigraphy in some regions and the timing of Late Pleistocene environmental changes, but few additional critical sites have been described in the past 25 years. The terrestrial stratigraphic record remains important for understanding the timing, sequence and patterns of glaciation and deglaciation during the last glacial/interglacial cycle. Former interpretations of ice-free areas in peripheral areas during the Last Glacial Maximum (LGM) are inconsistent with current stratigraphic and dating evidence. Significant challenges remain to determine events and patterns of glaciation during the Early and Middle Devensian, particularly in the context of offshore evidence and ice sheet modelling that indicate significant build-up of ice throughout much of the period. The terrestrial evidence broadly supports recent reconstructions of a highly dynamic and climate-sensitive British–Irish Ice Sheet (BIIS), which apparently reached its greatest thickness in Scotland between 30 and 27ka, before the global LGM. A thick (relative to topography) integrated ice sheet reaching the shelf edge with a simple ice-divide structure was replaced after the LGM by a much thinner one comprising multiple dispersion centres and a more complex flow structure
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