2,688 research outputs found

    A semantic-based system for querying personal digital libraries

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-540-28640-0_4. Copyright @ Springer 2004.The decreasing cost and the increasing availability of new technologies is enabling people to create their own digital libraries. One of the main topic in personal digital libraries is allowing people to select interesting information among all the different digital formats available today (pdf, html, tiff, etc.). Moreover the increasing availability of these on-line libraries, as well as the advent of the so called Semantic Web [1], is raising the demand for converting paper documents into digital, possibly semantically annotated, documents. These motivations drove us to design a new system which could enable the user to interact and query documents independently from the digital formats in which they are represented. In order to achieve this independence from the format we consider all the digital documents contained in a digital library as images. Our system tries to automatically detect the layout of the digital documents and recognize the geometric regions of interest. All the extracted information is then encoded with respect to a reference ontology, so that the user can query his digital library by typing free text or browsing the ontology

    Sterile Neutrino Fits to Short Baseline Neutrino Oscillation Measurements

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    This paper reviews short baseline oscillation experiments as interpreted within the context of one, two, and three sterile neutrino models associated with additional neutrino mass states in the ~1 eV range. Appearance and disappearance signals and limits are considered. We show that fitting short baseline data sets to a (3+3) model, defined by three active and three sterile neutrinos, results in an overall goodness of fit of 67%, and a compatibility of 90% among all data sets -- to be compared to the compatibility of 0.043% and 13% for a (3+1) and a (3+2) model, respectively. While the (3+3) fit yields the highest quality overall, it still finds inconsistencies with the MiniBooNE appearance data sets; in particular, the global fit fails to account for the observed MiniBooNE low-energy excess. Given the overall improvement, we recommend using the results of (3+2) and (3+3) fits, rather than (3+1) fits, for future neutrino oscillation phenomenology. These results motivate the pursuit of further short baseline experiments, such as those reviewed in this paper.Comment: Submitted to Advances in High Energy Physics Special Issue on Neutrino Physic

    Light Spectrum and Decay Constants in Full QCD with Wilson Fermions

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    We present results from an analysis of the light spectrum and the decay constants f_{\pi} and f_V^{-1} in Full QCD with n_f=2 Wilson fermions at a coupling of beta=5.6 on a 16^3x32 lattice.Comment: 3 pages, LaTeX with 4 eps figures, Talk presented at LATTICE96(spectrum

    Quark-gluon vertex in a momentum subtraction scheme

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    We compute the quark-gluon vertex in quenched QCD, in the Landau gauge using an off-shell mean-field O(a)-improved fermion action. The running coupling is calculated in an `asymmetric' momentum subtraction scheme (MOM~). We obtain a crude estimate for Lambda_MSbar=170+/-65 MeV, which is considerably lower than other determinations of this quantity. However, substantial systematic errors remain.Comment: Lattice2001(improvement); 3 pages, 3 figure

    Measuring Active-to-Sterile Neutrino Oscillations with Neutral Current Coherent Neutrino-Nucleus Scattering

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    Light sterile neutrinos have been introduced as an explanation for a number of oscillation signals at Δm21\Delta m^2 \sim 1 eV2^2. Neutrino oscillations at relatively short baselines provide a probe of these possible new states. This paper describes an accelerator-based experiment using neutral current coherent neutrino-nucleus scattering to strictly search for active-to-sterile neutrino oscillations. This experiment could, thus, definitively establish the existence of sterile neutrinos and provide constraints on their mixing parameters. A cyclotron-based proton beam can be directed to multiple targets, producing a low energy pion and muon decay-at-rest neutrino source with variable distance to a single detector. Two types of detectors are considered: a germanium-based detector inspired by the CDMS design and a liquid argon detector inspired by the proposed CLEAR experiment.Comment: 10 pages, 7 figure

    Towards the glueball spectrum of full QCD

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    We present first results on masses of the scalar and tensor glueballs as well as of the torelon from simulations of QCD with two light flavours of Wilson fermions. The gauge configurations of extent 16^3*32 at beta = 5.6 and kappa = 0.156, 0.157 and 0.1575 have been generated as part of the SESAM collaboration programme. The present lattice resolutions correspond to 1/a = 2.0-2.3 GeV and ratios m(pi)/m(rho) = 0.83, 0.76 and 0.71, respectively. Studies on larger lattice volumes and closer to the chiral limit are in progress.Comment: 4 pages, LaTeX, espcrc2 and epsf styles required, 4 epsf figures, poster presented by G. Bali at Lattice '9

    Nederlanders & afval: Jonge en oudere Nederlanders over afval

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    __Abstract_ De omgang met afval is één van de grootste mondiale vraagstukken van deze tijd. Door de stijgende welvaart en de groeiende consumptie wordt de hoeveelheid afval die we gezamenlijk produceren in de wereld almaar meer. Jaarlijks produceert de wereldbevolking ruim 12 miljard ton aan afval. Met name in ontwikkelingslanden en opkomende economieën zorgt de groeiende berg afval voor milieuproblemen en gezondheidsrisico’s. Bij gebrek aan goede ophaal- en verwerkingsfaciliteiten belanden grote hoeveelheden afval daar op straat en in de natuur. Bovendien vindt de verwerking van elektronisch afval uit westerse landen, dat naast waardevolle materialen ook giftige stoffen bevat, veelal plaats onder onveilige omstandigheden in Afrika en Azië. Naast giftig afval, zorgt ook plastic afval voor tal van problemen voor mens en dier. Zo vergaat plastic in zee tot kleine stukjes die gifstoffen opnemen en vervolgens door vissen en zeedieren worden opgegeten. In de Nederlandse politiek is plastic afval ook een onderwerp van discussie. Volgens gegevens van Agentschap NL produceerde Nederland in 2008 in totaal 63 miljoen ton aan afval; voldoende om de Amsterdam Arena dertig keer tot de nok toe te vullen. 84% van dit afval wordt nuttig (her) gebruikt, 13% wordt verbrand en 3% gestort of geloosd. NCDO onderzocht in samenwerking met TNS/NIPO hoe Nederlanders aankijken tegen afval en afvalverwerking

    Modeling larval connectivity of coral reef organisms in the Kenya-Tanzania region

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    Most coral reef organisms have a bipartite life-cycle; they are site attached to reefs as adults but have pelagic larval stages that allow them to disperse to other reefs. Connectivity among coral reef patches is critical to the survival of local populations of reef organisms, and requires movement across gaps that are not suitable habitat for recruitment. Knowledge of population connectivity among individual reef habitats within a broader geographic region of coral reefs has been identified as key to developing efficient spatial management strategies to protect marine ecosystems. The study of larval connectivity of marine organisms is a complex multidisciplinary challenge that is difficult to address by direct observation alone. An approach that couples ocean circulation models with individual based models (IBMs) of larvae with different degrees of life-history complexity has been previously used to assess connectivity patterns in several coral reef regions (e.g., the Great Barrier Reef (GBR) and the Caribbean). We applied the IBM particle tracking approach to the Kenya-Tanzania region, which exhibits strong seasonality in the alongshore currents due to the influence of the monsoon. A 3-dimensional (3D) ocean circulation model with 2 km horizontal resolution was coupled to IBMs that track virtual larvae released from each of 661 reef habitats, associated with 15 distinct regions. Given that reefs provide homes to numerous species, each with distinctive, and in aggregate very diverse life-histories, several life-history scenarios were modeled to examine the variety of dispersal and connectivity patterns possible. We characterize virtual larvae of Acropora corals and Acanthurus surgeonfish, two coral reef inhabitants with greatly differing pelagic life-histories, to examine the effects of short (50 days) pelagic larval durations (PLD), differences in swimming abilities (implemented as reef perception distances), and active depth keeping in reef connectivity. Acropora virtual larvae were modeled as 3D passive particles with a precompetency period of 4 days, a total PLD of 12 days and a perception distance of 10 m. Acanthurus virtual larvae were characterized by 50 days precompetency period, a total PLD of 72 days and a perception distance of 4 km. Acanthurus virtual larvae were modeled in two ways — as 3D passive particles and including an idealized ontogenetic vertical migration behavior. A range of distances within which larvae were able to perceive reefs and directionally swim to settle on them during the competency period were evaluated. The influence of interannual environmental variations was assessed for two years (2000, 2005) of contrasting physics. The spatial scale of connectivity is much smaller for the short PLD coral, with successful connections restricted to a 1° radius (~100 km) around source reefs. In contrast, long distance connections from the southern to the northernmost reefs (~950 km) are common for virtual Acanthurids. Successful settlement for virtual Acropora larvae was 20% overall, with cross-region recruitment much increased compared to the coral larvae. Approximately 8% of Acropora larvae that successfully settled, recruited to their source reef (self-recruitment), an important proportion compared to only 1-2 % self-recruitment for Acanthurus. These rates and dispersal distances are similar to previous modelling studies of similar species in other coral reef regions and agree well with the few observational studies within the Kenya-Tanzania region

    Changes in self-reported pre- to postinjury coping styles in the first 3 years after traumatic brain injury and the effects on psychosocial and emotional functioning and quality of life

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    OBJECTIVE:: To examine the influence of self-reported preinjury coping on postinjury coping, psychosocial functioning, emotional functioning, and quality of life at 1 year following traumatic brain injury (TBI). SETTING:: Inpatient hospital and community. PARTICIPANTS:: One hundred seventy-four participants with TBI. DESIGN:: Prospective, longitudinal design. Participants were assessed at 5 time points: after emerging from posttraumatic amnesia, and at 6, 12, 24, and 36 months postinjury. MAIN MEASURES:: Coping Scale for Adults-Short Version; Quality of Life Inventory; Sydney Psychosocial Reintegration Scale; Hospital Anxiety and Depression Scale. RESULTS:: High preinjury use of nonproductive coping style predicted high use of nonproductive coping, more anxiety, and lower psychosocial functioning at 1 year postinjury. Increased use of nonproductive coping and decreased use of productive coping predicted poorer psychosocial outcome at 1 year post-TBI. Use of both productive and nonproductive coping decreased in the first 6 to 12 months post-TBI relative to preinjury. Unlike productive coping, nonproductive coping reached preinjury levels within 3 years postinjury. CONCLUSION:: The findings support identification of individuals at risk of relying on nonproductive coping and poorer psychosocial outcome following TBI. In addition, the results emphasize the need to implement timely interventions to facilitate productive coping and reduce the use of nonproductive coping in order to maximize favorable long-term psychosocial outcome
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