455 research outputs found

    Comparative analysis of knowledge representation and reasoning requirements across a range of life sciences textbooks.

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    BackgroundUsing knowledge representation for biomedical projects is now commonplace. In previous work, we represented the knowledge found in a college-level biology textbook in a fashion useful for answering questions. We showed that embedding the knowledge representation and question-answering abilities in an electronic textbook helped to engage student interest and improve learning. A natural question that arises from this success, and this paper's primary focus, is whether a similar approach is applicable across a range of life science textbooks. To answer that question, we considered four different textbooks, ranging from a below-introductory college biology text to an advanced, graduate-level neuroscience textbook. For these textbooks, we investigated the following questions: (1) To what extent is knowledge shared between the different textbooks? (2) To what extent can the same upper ontology be used to represent the knowledge found in different textbooks? (3) To what extent can the questions of interest for a range of textbooks be answered by using the same reasoning mechanisms?ResultsOur existing modeling and reasoning methods apply especially well both to a textbook that is comparable in level to the text studied in our previous work (i.e., an introductory-level text) and to a textbook at a lower level, suggesting potential for a high degree of portability. Even for the overlapping knowledge found across the textbooks, the level of detail covered in each textbook was different, which requires that the representations must be customized for each textbook. We also found that for advanced textbooks, representing models and scientific reasoning processes was particularly important.ConclusionsWith some additional work, our representation methodology would be applicable to a range of textbooks. The requirements for knowledge representation are common across textbooks, suggesting that a shared semantic infrastructure for the life sciences is feasible. Because our representation overlaps heavily with those already being used for biomedical ontologies, this work suggests a natural pathway to include such representations as part of the life sciences curriculum at different grade levels

    Model-Independent Bound on the Dark Matter Lifetime

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    If dark matter (DM) is unstable, in order to be present today, its lifetime needs to be longer than the age of the Universe, t_U ~ 4 10^{17} s. It is usually assumed that if DM decays it would do it with some strength through a radiative mode. In this case, very constraining limits can be obtained from observations of the diffuse gamma ray background. However, although reasonable, this is a model-dependent assumption. Here our only assumption is that DM decays into, at least, one Standard Model (SM) particle. Among these, neutrinos are the least detectable ones. Hence, if we assume that the only SM decay daughters are neutrinos, a limit on their flux from DM decays in the Milky Way sets a conservative, but stringent and model-independent bound on its lifetime.Comment: 4 pp, 1 fig; published version with extended discussion, updated figure and added reference

    Embedding knowledge and value of a brand into sustainability for differentiation

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    This is the post-print version of the final paper published in the Journal of World Business (under the provisional title "Embedding sustainability into brand knowledge and brand value for brand differentiation"). The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.Organisations offer products to consumers, buyers often question if the product or its production process are linked to the environmental, social or economic challenges being faced by mankind. Inquisitiveness of customers in this direction points towards an opportunity for marketers to create differentiation based on the concerns of brand towards overall issue of sustainability. The authors have synthesized knowledge from various domains with a positivistic approach to understand sustainability from the perspective of branding. Using empirical knowledge this study recommends embedding sustainability into brand knowledge and brand value for creating a differentiation for the brand in a competitive market

    Xenopus staufen2 is required for anterior endodermal organ formation

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    Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in genesis 50 (2012): 251-259, doi:10.1002/dvg.22000.Defining the regulatory molecular networks involved in patterning the developing anterior endoderm is essential to understanding how the pancreas, liver, stomach and duodenum are discretely specified from each other. In this study, we analyzed the expression and function of the double-stranded RNA-binding protein Staufen2 in Xenopus laevis endoderm. We found that staufen2 was broadly expressed within the developing endoderm beginning at gastrulation becoming localized to the anterior endoderm at later stages. Through morpholino-mediated knockdown, we demonstrate that Staufen2 function is required for proper formation of the stomach, liver and pancreas. We define that its function is required during gastrulation for proper patterning of the dorsal-ventral axis and that it acts to regulate expression of BMP signaling components.This work was supported by grants from the National Institutes of Health (DK077197) to M.E.H. and from the Canadian Institute of Health Research (Frederick Banting and Charles Best Canada Graduate Scholarships - Doctoral Awards) to C.K.B

    Neutrino Physics at the Turn of the Millenium

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    Recent solar & atmospheric nu-data strongly indicate need for physics beyond the Standard Model. I review the ways of reconciling them in terms of 3-nu oscillations. Though not implied by data, bi-maximal nu-mixing models emerge as a possibility. SUSY with broken R-parity provides an attractive way to incorporate it, opening the possibility of testing nu-anomalies at high- energy colliders such as the LHC or at the upcoming long-baseline or nu- factory experiments. Reconciling, in addition, the LSND hint requires a fourth, light sterile neutrino, nus. The simplest are the most symmetric scenarios, in which 2 of the 4 neutrinos are maximally-mixed and lie at the LSND scale, while the others are at the solar scale. The lightness of nus, the nearly maximal atmospheric mixing, and the solar/atmospheric splittings all follow naturally from the assumed lepton-number symmetry and its breaking. These basic schemes can be distinguished at neutral-current-sensitive solar & atmospheric neutrino experiments such as SNO. However underground experiments have not yet proven neutrino masses, as there are many alternatives. For example flavour changing interactions can play an important role in the explanation of solar and contained atmospheric data and could be tested e.g through \mu \to e + \gamma, \mu-e conversion in nuclei, unaccompanied by neutrino-less double beta decay. Conversely, a short-lived numu might play a role in the explanation of the atmospheric data. Finally, in the presence of a nus, a long-lived heavy nutau could delay the time at which the matter and radiation contributions to the energy density of the Universe become equal, reducing density fluctuations on smaller scales, thus saving the standard CDM scenario, while the light nue, numu and nus would explain the solar & atmospheric data.Comment: Invited talk at 2nd International Conference on Non-Accelerator New Physics (NANP-99), Dubna, June 28 - July 3, 199

    Generalization and fine mapping of European ancestry-based central adiposity variants in African ancestry populations

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    Central adiposity measures such as waist circumference (WC) and waist-to-hip ratio (WHR) are associated with cardiometabolic disorders independently of BMI and are gaining clinically utility. Several studies report genetic variants associated with central adiposity, but most utilize only European ancestry populations. Understanding whether the genetic associations discovered among mainly European descendants are shared with African ancestry populations will help elucidate the biological underpinnings of abdominal fat deposition

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

    Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV

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    The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0 degree to 58 degree. Due to the large exposure of about 150 m2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 GeV and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003 (stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure
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