257 research outputs found

    An elementary proof of uniqueness of the particle trajectories for solutions of a class of shear-thinning non-Newtonian 2D fluids

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    We prove some regularity results for a class of two dimensional non-Newtonian fluids. By applying results from [Dashti and Robinson, Nonlinearity, 22 (2009), 735-746] we can then show uniqueness of particle trajectories

    Age and Depositional Environment of Whale-Bearing Sedimentary Succession from the Lower Pliocene of Tuscany (Italy): Insights from Palaeomagnetism, Calcareous Microfossils and Facies Analyses

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    A c. 31 m thick section straddling the fossil find of an Early Pliocene baleen whale ("Brunella", hereafter), made in 2007 in the sedimentary fill of the Middle Ombrone Basin of Tuscany, is investigated for depositional age and environment combining palaeomagnetic, micropalaeontological (Foraminifera and calcareous nannofossils) and sedimentary facies analyses. Resting unconformably onto Late Miocene continental deposits, the Early Pliocene marine deposits include, from bottom to top, a coarse-grained wave-winnowing lag, the few metres-thick fossiliferous sandstone bedset from which Brunella was unearthed, and several metres of clays. The stratigraphic organisation of these deposits indicate deposition in a deepening upward inner shelf environment. Successful isolation of characteristic remanent magnetisation and calcareous nannofossil content indicate the investigated marine section was deposited during the interval of polarity Chron C3n.2n corresponding to the basal part of the Mediterranean nannofossil zone MNN13 (between Helicosphaera sellii Base common and the Amaurolithus primus Top) and allow estimating the depositional age of Brunella to c. 4.6 Ma. Sedimentary facies, benthic Foraminifera association and anisotropy of magnetic susceptibility characterising the deposits that embedded Brunella suggest deposition above the fair-weather base level

    A numerical code for the simulation of magma-rocks dynamics

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    We present a numerical code for the simulation of the dynamics of compressible to incompressible, multicomponent ows, based on the _nite element algorithm by Hauke & Hughes (1998). Balance equations for mass, momentum, energy and composition are solved with space-time Galerkin least-squares and discontinuity-capturing stabilizing techniques. The code is used to study the dynamics of convection and mixing in magmatic systems such as replenishment of magma chambers and volcanic conduits, and it reveals the occurrence of previously not described processes. The uid-structure interaction of fully coupled magma-rock dynamics is being implemented by using the deforming-spatial domain method by Tezduyar (2006), that intrinsecally includes moving meshes

    Maximizing team synergy in AI-related interdisciplinary groups: an interdisciplinary-by-design iterative methodology

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    In this paper, we propose a methodology to maximize the benefits of interdisciplinary cooperation in AI research groups. Firstly, we build the case for the importance of interdisciplinarity in research groups as the best means to tackle the social implications brought about by AI systems, against the backdrop of the EU Commission proposal for an Artificial Intelligence Act. As we are an interdisciplinary group, we address the multi-faceted implications of the mass-scale diffusion of AI-driven technologies. The result of our exercise lead us to postulate the necessity of a behavioural theory that standardizes the interaction process of interdisciplinary groups. In light of this, we conduct a review of the existing approaches to interdisciplinary research on AI appliances, leading to the development of methodologies like ethics-by-design and value-sensitive design, evaluating their strengths and weaknesses. We then put forth an iterative process theory hinging on a narrative approach consisting of four phases: (i) definition of the hypothesis space, (ii) building-up of a common lexicon, (iii) scenario-building, (iv) interdisciplinary self-assessment. Finally, we identify the most relevant fields of application for such a methodology and discuss possible case studies

    Eroina e asma bronchiale

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    Il broncospasmo da eroina, di recente individuazione, Ăš di raro riscontro probabilmente perchĂ© poco conosciuto o non adeguatamente indagato. L’eroina, principalmente attraverso un meccanismo di istamino-liberazione, induce ostruzione bronchiale che appare piĂč grave negli asmatici cronici e negli atopici manifestandosi pochi minuti dopo l’inalazione della sostanza. Il narcotico puĂČ determinare: a) broncospasmo con insufficienza respiratoria che puĂČ richiedere cure intensive con ricorso alla ventilazione meccanica; b) depressione del centro bulbare del respiro; c) sintomatologia sistemica; d) sindrome da astinenza, che si puĂČ presentare poco dopo la risoluzione dell’episodio acuto. Un rapporto empatico con il paziente puĂČ agevolare il percorso diagnostico; infatti, la sua reticenza a svelare l’abitudine voluttuaria ritarda l’individuazione dell’esposizione alla sostanza. CiĂČ puĂČ comportare un trattamento terapeutico ritardato, con conseguente aggravamento della condizione clinica a possibile evoluzione infausta.Bronchospasm caused by inhaled heroin has recently been identified. The condition has been rarely identified and/or not sufficiently investigated. Through the reaction mediated by histamine, heroin causes a bronchial obstruction that seems more severe in chronic asthmatic and atopic individuals, immediately after inhalating the substance. Heroin can reveal: a) bronchospasm with respiratory failure that may require intensive care up to mechanical ventilation; b) depression of the bulbar center of breath; c) systemic symptoms; d) withdrawal syndrome that may be evident after an acute clinical event. Even though an empathic relationship between the patient and the doctor can facilitate the diagnostic process, a lack of early identification of exposure to the substance, due to the patient’s hesitation to disclose his/her behavior, may cause a delay in the treatment and a worsening of clinical conditions with unfavourable development

    Estimation of the exposure for the air shower detection mode of EUSO-SPB1

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    EUSO-SPB1 was a balloon-borne pathfinder mission of the JEM-EUSO (Joint Experiment Missions for the Extreme Universe Space Observatory) program. A 12-day long flight started from New Zealand on April 25th, 2017 on-board the NASA's Super Pressure Balloon. With capability of detecting EeV energy air showers, the data acquisition was performed using a 1 m^2 two-Fresnel-lens UV-sensitive telescope with fast readout electronics in the air shower detection mode over ~30 hours at ~16--30 km above South Pacific. Using a variety of approaches, we searched for air shower events. Up to now, no air shower events have been identified. The effective exposure, regarding the role of the clouds in particular, was estimated based on the air shower and detector simulations together with a numerical weather forecast model. Compared with the case assuming the fully clear atmosphere conditions, more than ~60% of showers are detectable regardless the presence of the clouds. The studies in the present work will be applied in the follow-up pathfinders and in the future full-scale missions in the JEM-EUSO program

    Pre-flight qualification tests of the Mini-EUSO telescope engineering model

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    International audienceMini-EUSO is part of the JEM-EUSO program and operates on board the International Space Station (ISS). It is a UV-telescope with single-photon counting capability looking at nighttime downwards to the Earth through a nadir-facing UV-transparent window. As part of the pre-flight tests, the Mini-EUSO engineering model, a telescope with 1/9 of the original focal surface and a lens of 2.5 cm diameter, has been built and tested. Tests of the Mini-EUSO engineering model have been made in laboratory and in open-sky conditions. Laboratory tests have been performed at the TurLab facility, located at the Physics Department of the University of Turin, equipped with a rotating tank containing different types of materials and light sources. In this way, the configuration for the observation of the Earth from space was emulated, including the Mini-EUSO trigger schemes. In addition to the qualification and calibration tests, the Mini-EUSO engineering model has also been used to evaluate the possibility of using a JEM-EUSO-type detector for applications such as observation of space debris. Furthermore, observations in open-sky conditions allowed the studies of natural light sources such as stars, meteors, planets, and artificial light sources such as airplanes, satellites reflecting the sunlight, and city lights. Most of these targets could be detected also with Mini-EUSO. In this paper, the tests in laboratory and in open-sky conditions are reported, as well as the obtained results. In addition, the contribution that such tests provided to foresee and improve the performance of Mini-EUSO on board the ISS is discussed

    Simulations studies for the Mini-EUSO detector

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    Mini-EUSO is a mission of the JEM-EUSO program flying onboard the International Space Station since August 2019. Since the first data acquisition in October 2019, more than 35 sessions have been performed for a total of 52 hours of observations. The detector has been observing Earth at night-time in the UV range and detected a wide variety of transient sources all of which have been modelled through Monte Carlo simulations. Mini-EUSO is also capable of detecting meteors and potentially space debris and we performed simulations for such events to estimate their impact on future missions for cosmic ray science from space. We show here examples of the simulation work done in this framework to analyse the Mini-EUSO data. The expected response of Mini-EUSO with respect to ultra high energy cosmic ray showers has been studied. The efficiency curve of Mini-EUSO as a function of primary energy has been estimated and the energy threshold for Cosmic Rays has been placed to be above 10^{21} eV. We compared the morphology of several transient events detected during the mission with cosmic ray simulations and excluded that they can be due to cosmic ray showers. To validate the energy threshold of the detector, a system of ground based flashers is being used for end-to-end calibration purposes. We therefore implemented a parameterisation of such flashers into the JEM-EUSO simulation framework and studied the response of the detector with respect to such sources
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