2,379 research outputs found

    Fifty years of spellchecking

    Get PDF
    A short history of spellchecking from the late 1950s to the present day, describing its development through dictionary lookup, affix stripping, correction, confusion sets, and edit distance to the use of gigantic databases

    A dust-parallax distance of 19 megaparsecs to the supermassive black hole in NGC 4151

    Full text link
    The active galaxy NGC 4151 has a crucial role as one of only two active galactic nuclei for which black hole mass measurements based on emission line reverberation mapping can be calibrated against other dynamical methods. Unfortunately, effective calibration requires an accurate distance to NGC 4151, which is currently not available. Recently reported distances range from 4 to 29 megaparsecs (Mpc). Strong peculiar motions make a redshift-based distance very uncertain, and the geometry of the galaxy and its nucleus prohibit accurate measurements using other techniques. Here we report a dust-parallax distance to NGC 4151 of DA=19.02.6+2.4D_A = 19.0^{+2.4}_{-2.6} Mpc. The measurement is based on an adaptation of a geometric method proposed previously using the emission line regions of active galaxies. Since this region is too small for current imaging capabilities, we use instead the ratio of the physical-to-angular sizes of the more extended hot dust emission as determined from time-delays and infrared interferometry. This new distance leads to an approximately 1.4-fold increase in the dynamical black hole mass, implying a corresponding correction to emission line reverberation masses of black holes if they are calibrated against the two objects with additional dynamical masses.Comment: Authors' version of a letter published in Nature (27 November 2014); 8 pages, 5 figures, 1 tabl

    Developing Crisis Training Software for Local Governments – From User Needs to Generic Requirements

    Get PDF
    In this paper we analyze and present the generic requirements identified for a software aiming at supporting crisis management training in local governments. The generic requirements are divided into overall requirements, requirements connected to the trainer’s role and requirements connected to the trainee’s role. Moreover, the requirements are mapped to problems as well as opportunities. Finally, we present examples of elaborations of the addressed requirements based on software design considerations. In our work we applied a design science approach and the artifact presented in this paper is a list of generic requirement. The presented requirements and the systems development process used, provide guidelines for systems analysts and developers in future systems development projects aiming at constructing new software for crisis management training

    A relocatable ocean model in support of environmental emergencies

    Get PDF
    During the Costa Concordia emergency case, regional, subregional, and relocatable ocean models have been used together with the oil spill model, MEDSLIK-II, to provide ocean currents forecasts, possible oil spill scenarios, and drifters trajectories simulations. The models results together with the evaluation of their performances are presented in this paper. In particular, we focused this work on the implementation of the Interactive Relocatable Nested Ocean Model (IRENOM), based on the Harvard Ocean Prediction System (HOPS), for the Costa Concordia emergency and on its validation using drifters released in the area of the accident. It is shown that thanks to the capability of improving easily and quickly its configuration, the IRENOM results are of greater accuracy than the results achieved using regional or subregional model products. The model topography, and to the initialization procedures, and the horizontal resolution are the key model settings to be configured. Furthermore, the IRENOM currents and the MEDSLIK-II simulated trajectories showed to be sensitive to the spatial resolution of the meteorological fields used, providing higher prediction skills with higher resolution wind forcing.MEDESS4MS Project; TESSA Project; MyOcean2 Projectinfo:eu-repo/semantics/publishedVersio

    Updating known distribution models for forecasting climate change impact on endangered species

    Get PDF
    To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their distributional response to climate change, especially under the current situation of rapid change. However, these predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of known species distribution models, but proceeding to update them with the variables yielded by climatic models before projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered Bonelli’s Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that the main threat for this endangered species would not be climate change, since all forecasting models show that its distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of linking conservation biology with distribution modelling by updating existing models, frequently available for endangered species, considering all the known factors conditioning the species’ distribution, instead of building new models that are based on climate change variables only.Ministerio de Ciencia e Innovación and FEDER (project CGL2009-11316/BOS

    Prefrontal and anterior cingulate cortex abnormalities in Tourette Syndrome: evidence from voxel-based morphometry and magnetization transfer imaging

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Pathophysiological evidence suggests an involvement of fronto-striatal circuits in Tourette syndrome (TS). To identify TS related abnormalities in gray and white matter we used optimized voxel-based morphometry (VBM) and magnetization transfer imaging (MTI) which are more sensitive to tissue alterations than conventional MRI and provide a quantitative measure of macrostructural integrity.</p> <p>Methods</p> <p>Volumetric high-resolution anatomical T1-weighted MRI and MTI were acquired in 19 adult, unmedicated male TS patients without co-morbidities and 20 age- and sex-matched controls on a 1.5 Tesla neuro-optimized GE scanner. Images were pre-processed and analyzed using an optimized version of VBM in SPM2.</p> <p>Results</p> <p>Using VBM, TS patients showed significant decreases in gray matter volumes in prefrontal areas, the anterior cingulate gyrus, sensorimotor areas, left caudate nucleus and left postcentral gyrus. Decreases in white matter volumes were detected in the right inferior frontal gyrus, the left superior frontal gyrus and the anterior corpus callosum. Increases were found in the left middle frontal gyrus and left sensorimotor areas. In MTI, white matter reductions were seen in the right medial frontal gyrus, the inferior frontal gyrus bilaterally and the right cingulate gyrus. Tic severity was negatively correlated with orbitofrontal structures, the right cingulate gyrus and parts of the parietal-temporal-occipital association cortex bilaterally.</p> <p>Conclusion</p> <p>Our MRI <it>in vivo </it>neuropathological findings using two sensitive and unbiased techniques support the hypothesis that alterations in frontostriatal circuitries underlie TS pathology. We suggest that anomalous frontal lobe association and projection fiber bundles cause disinhibition of the cingulate gyrus and abnormal basal ganglia function.</p

    An unusual presentation of Castleman's Disease:a case report

    Get PDF
    BACKGROUND: Castleman's disease (CD), a rare condition of uncertain etiology, involves a massive proliferation of lymphoid tissues and typically presents as mediastinal masses. We describe a patient with CD who presented with diffuse adenopathy involving the inguinal, paratracheal, retroperitoneal, axillary, and pelvic regions. CASE PRESENTATION: Case report describing presentation, work-up, management and clinical course of a patient with Castleman's disease in the setting of a county hospital in metropolitan area. Patient was treated with chemotherapeutic agents. CONCLUSIONS: To our knowledge, this represents the first case of CD involving an HIV-positive patient with a negative Human Herpes Virus (HHV-8) viral panel. Because patients with similar clinical histories are at high risk for the development of non-Hodgkin's lymphoma and Kaposi sarcoma, regular medical surveillance is recommended

    Effects of habitat and land use on breeding season density of male Asian Houbara Chlamydotis macqueenii

    Get PDF
    Landscape-scale habitat and land-use influences on Asian Houbara Chlamydotis macqueenii (IUCN Vulnerable) remain unstudied, while estimating numbers of this cryptic, low-density, over-hunted species is challenging. In spring 2013, male houbara were recorded at 231 point counts, conducted twice, across a gradient of sheep density and shrub assemblages within 14,300 km² of the Kyzylkum Desert, Uzbekistan. Four sets of models related male abundance to: (1) vegetation structure (shrub height and substrate); (2) shrub assemblage; (3) shrub species composition (multidimensional scaling); (4) remote-sensed derived land-cover (GLOBCOVER, 4 variables). Each set also incorporated measures of landscape rugosity and sheep density. For each set, multi-model inference was applied to generalised linear mixed models of visit-specific counts that included important detectability covariates and point ID as a random effect. Vegetation structure received strongest support, followed by shrub species composition and shrub assemblage, with weakest support for the GLOBCOVER model set. Male houbara numbers were greater with lower mean shrub height, more gravel and flatter surfaces, but were unaffected by sheep density. Male density (mean 0.14 km-2, 95% CI, 0.12‒0.15) estimated by distance analysis differed substantially among shrub assemblages, being highest in vegetation dominated by Salsola rigida (0.22 [CI, 0.20‒0.25]), high in areas of S. arbuscula and Astragalus (0.14 [CI, 0.13‒0.16] and 0.15 [CI, 0.14‒0.17] respectively), lower (0.09 [CI, 0.08‒0.10]) in Artemisia and lowest (0.04 [CI, 0.04‒0.05]) in Calligonum. The study area was estimated to hold 1,824 males (CI: 1,645‒2,030). The spatial distribution of relative male houbara abundance, predicted from vegetation structure models, had the strongest correspondence with observed numbers in both model-calibration and the subsequent year’s data. We found no effect of pastoralism on male distribution but potential effects on nesting females are unknown. Density differences among shrub communities suggest extrapolation to estimate country- or range-wide population size must take account of vegetation composition
    corecore