2,151 research outputs found

    On the evaluation of photogrammetric methods for dense 3D surface reconstruction in a metrological context.

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    This paper discusses a methodology to evaluate the accuracy of recently developed image-based 3D modelling techniques. So far, the emergence of these novel methods has not been supported by the definition of an internationally recognized standard which is fundamental for user confidence and market growth. In order to provide an element of reflection and solution to the different communities involved in 3D imaging, a promising approach is presented in this paper for the assessment of both metric quality and limitations of an open-source suite of tools (Apero/MicMac), developed for the extraction of dense 3D point clouds from a set of un- ordered 2D images. The proposed procedural workflow is performed within a metrological context, through inter-comparisons with \u2018reference\u2019 data acquired with two hemispherical laser scanners, one total station, and one laser tracker. The methodology is applied to two case studies, designed in order to analyse the software performances in dealing with both outdoor and environmentally controlled conditions, i.e. the main entrance of Cath\ue9drale de la Major (Marseille, France) and a custom-made scene located at National Research Council of Canada 3D imaging Metrology Laboratory (Ottawa). Comparative data and accuracy evidence produced for both tests allow the study of some key factors affecting 3D model accuracy

    The Frontier Mountain meteorite gap (Antarctica)

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    The Frontier Mountain blue ice field is an important Antarctic meteorite trap which has yielded 472 meteorite specimens since its discovery in 1984. Remote sensing analyses and field campaigns from 1993 to 1999 have furnished new glaciological data on ice flow, ice thickness, bedrock topography, ice ablation and surface mass transport by wind, along with detailed descriptions of the field situation at the trap. This solid set of data combined with an updated meteorite distribution map and terrestrial ages available from literature allows us to better describe the nature of the concentration mechanism. In particular, we observe that the meteorite trap forms in a blue ice field i) located upstream of an absolute and a shallow subice barriers; ii) characterized by compressive ice flow with horizontal velocities decreasing from 100 to <10 cm a-1 on approaching the obstacle; iii) undergoing mean ablation rates of 6.5 cm a-1; iv) nourished by a limited snow accumulation zone extending ~20 km upstream of the blue ice area. We also draw the following conclusions: i) the origin of the meteorite trap can be explained according to the present-day glaciological situation; ii) the meteorite concentration develops according to the general principles of the “ice flow model”; iii) the accumulation model can be described as “stagnant ice or slow-moving ice against an absolute and submerged barriers”, according to the descriptive schemes present in literature; iv) the Frontier Mountain ice field is an effective trap for meteorites weighing more than ~200 g; for smaller masses, the combination of wind and glacial drift may remove meteorites in less than a few tens of ka; v) although the activation age of the FM trap is not yet constrained, we infer that one of the most important findsite may be as old as 50 ka, i.e. older than the Last Glacial Maximum

    Small RNA sequencing of cryopreserved semen from single bull revealed altered miRNAs and piRNAs expression between High- and Low-motile sperm populations

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    Putative piRNA clusters that were assigned by proTRAC to the High Motile (HM) and Low Motile (LM) sperm fractions. (XLSX 21 kb

    What makes re-finding information difficult? A study of email re-finding

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    Re-nding information that has been seen or accessed before is a task which can be relatively straight-forward, but often it can be extremely challenging, time-consuming and frustrating. Little is known, however, about what makes one re-finding task harder or easier than another. We performed a user study to learn about the contextual factors that influence users' perception of task diculty in the context of re-finding email messages. 21 participants were issued re-nding tasks to perform on their own personal collections. The participants' responses to questions about the tasks combined with demographic data and collection statistics for the experimental population provide a rich basis to investigate the variables that can influence the perception of diculty. A logistic regression model was developed to examine the relationships be- tween variables and determine whether any factors were associated with perceived task diculty. The model reveals strong relationships between diculty and the time lapsed since a message was read, remembering when the sought-after email was sent, remembering other recipients of the email, the experience of the user and the user's ling strategy. We discuss what these findings mean for the design of re-nding interfaces and future re-finding research

    Genotyping and antifungal susceptibility of Dipodascus capitatus isolated in a neonatal intensive care unit of a sicilian hospital

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    In August 2015, Dipodascus capitatus was isolated from two patients admitted to the neonatal intensive care unit. Nosocomial acquisition of the fungus was suspected and epidemiological studies were undertaken. The patients were simultaneously hospitalized, and the comparison of the two isolates by two independent molecular typing methods have confirmed clonal dissemination of a single strain of D. capitatus. Antimicrobial susceptibility testing was useful for identifying the appropriated antifungal therapy in micafungin. To our knowledge these are the first described cases of neonatal D. capitatus infection and also the first report of successful treatment by micafungin.In August 2015, Dipodascus capitatus was isolated from two patients admitted to the neonatal intensive care unit. Nosocomial acquisition of the fungus was suspected and epidemiological studies were undertaken. The patients were simultaneously hospitalized, and the comparison of the two isolates by two independent molecular typing methods have confirmed clonal dissemination of a single strain of D. capitatus. Antimicrobial susceptibility testing was useful for identifying the appropriated antifungal therapy in micafungin. To our knowledge these are the first described cases of neonatal D. capitatus infection and also the first report of successful treatment by micafungin

    An ABS control logic based on wheel force measurement

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    The paper presents an anti-lock braking system (ABS) control logic based on the measurement of the longitudinal forces at the hub bearings. The availability of force information allows to design a logic that does not rely on the estimation of the tyre-road friction coefficient, since it continuously tries to exploit the maximum longitudinal tyre force. The logic is designed by means of computer simulation and then tested on a specific hardware in the loop test bench: the experimental results confirm that measured wheel force can lead to a significant improvement of the ABS performances in terms of stopping distance also in the presence of road with variable friction coefficien

    The scientist' experience in participated science communication

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    Since 2006 a small group of researchers from the Italian National Institute for Nuclear Physics started to realized one of the first European Researchers' Night in Europe: a one night-event, supported by the European Commission, that falls every last Friday of September to promote the researcher's figure and its work. Today, after thirteen editions, the project has evolved by involving more than 60 scientific partners and more than 400 events/year spread from the North to the South of Italy in 30 cities, captivating more than 50.000 attendees with a not negligible impact on the people and the press. During the years, the project has followed and sometimes anticipated the science communication trend, and BEES (BE a citizEn Scientist) is the last step of this long and thrilling evolution that brought to a huge public engagement in our territory. The experience, the methodology, and the major successful examples of the organized events are presented together with the results of the long term project impact
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