33 research outputs found

    An Iterative Procedure for the Analysis of Nonlinear Elastic Systems Subjected to Uniaxial Loading and Large Displacements

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    The paper deals with an iterative procedure for the solution of elastic problems, for which the large displacement theory must be considered. It is shown that the algorithm, based upon a non-traditional iterative scheme, tends to converge to the correct solution and some numerical tests are considered, by assuming a linear and piecewise-linear material model

    The Glare Effect Test and the Impact of Age on Luminosity Thresholds

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    The glare effect (GE) is an illusion in which a white region appears self-luminous when surrounded by linearly decreasing luminance ramps. It has been shown that the magnitude of the luminosity effect can be modulated by manipulating the luminance range of the gradients. In the present study we tested the thresholds for the GE on two groups of adults: young (20–30 years old) and elderly (60–75 years old). Purpose of our perspective study was to test the possibility of transforming the GE into a test that could easily measure thresholds for luminosity and discomfort glare. The Glare Effect Test (GET) consisted in 101 printed cards that differed from each other for the range of luminance ramps. Participants were assessed with GET and a battery of visual tests: visual acuity, contrast sensitivity, illusion of length perception, and Ishihara test. Specifically in the GET, participants were required to classify cards on the basis of two reference cards (solid black-no gradient; full range black to white gradient). PSEs of the GE show no correlation with the other visual tests, revealing a divergent validity. A significant difference between young and elderly was found: contrary to our original expectations, luminosity thresholds of GE for elderly were higher than those for young, suggesting a non-direct relationship between luminosity perception and discomfort glare

    Evidence of top-down modulation of the Brentano illusion but not of the glare effect by transcranial direct current stimulation

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    Transcranial direct current stimulation (tDCS) has been widely used for modulating sensory, motor and cognitive functions, but there are only few attempts to induce and change illusory perception. Visual illusions have been the most traditional and effective way to investigate visual processing through the comparison between physical reality and subjective reports. Here we used tDCS to modulate two different visual illusions, namely the Brentano illusion and the glare effect, with the aim of uncovering the influence of top-down mechanisms on bottom-up visual perception in two experiments. In Experiment 1, to a first group of subjects, real and sham cathodal tDCS (2 mA, 10 min) were applied over the left and right posterior parietal cortices (PPC). In Experiment 2, real and sham cathodal tDCS were applied to the left and right occipital cortices (OC) to a second group of participants. Results showed that tDCS was effective in modulating only the Brentano illusion, but not the glare effect. tDCS increased the Brentano illusion but specifically for the stimulated cortical area (right PPC), illusion direction (leftward), visual hemispace (left), and illusion length (160 mm). These findings suggest the existence of an inhibitory modulation of top-down mechanisms on bottom-up visual processing specifically for the Brentano illusion, but not for the glare effect. The lack of effect of occipital tDCS should consider the possible role of ocular compensation or of the unstimulated hemisphere, which deserves further investigation

    Is There Light at the Ends of the Tunnel? Wireless Sensor Networks for Adaptive Lighting in Road Tunnels

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    Existing deployments of wireless sensor networks (WSNs) are often conceived as stand-alone monitoring tools. In this paper, we report instead on a deployment where the WSN is a key component of a closed-loop control system for adaptive lighting in operational road tunnels. WSN nodes along the tunnel walls report light readings to a control station, which closes the loop by setting the intensity of lamps to match a legislated curve. The ability to match dynamically the lighting levels to the actual environmental conditions improves the tunnel safety and reduces its power consumption. The use of WSNs in a closed-loop system, combined with the real-world, harsh setting of operational road tunnels, induces tighter requirements on the quality and timeliness of sensed data, as well as on the reliability and lifetime of the network. In this work, we test to what extent mainstream WSN technology meets these challenges, using a dedicated design that however relies on wellestablished techniques. The paper describes the hw/sw architecture we devised by focusing on the WSN component, and analyzes its performance through experiments in a real, operational tunnel

    Active degassing across the Maltese Islands (Mediterranean Sea) and implications for its neotectonics

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    The Maltese Islands, located in the central Mediterranean Sea, are intersected by two normal fault systems associated with continental rifting to the south. Due to a lack of evidence for offshore displacement and insignificant historical seismicity, the systems are thought to be inactive and the rift-related deformation is believed to have ceased. In this study we integrate aerial, marine and onshore geological, geophysical and geochemical data from the Maltese Islands to demonstrate that the majority of faults offshore the archipelago underwent extensional to transtensional deformation during the last 20 ka. We also document an active fluid flow system responsible for degassing of CH4 and CO2. The gases migrate through carbonate bedrock and overlying sedimentary layers via focused pathways, such as faults and pipe structures, and possibly via diffuse pathways, such as fractures. Where the gases seep offshore, they form pockmarks and rise through the water column into the atmosphere. Gas migration and seepage implies that the onshore and offshore faults systems are permeable and that they were active recently and simultaneously. The latter can be explained by a transtensional system involving two right-stepping, right-lateral NW-SE trending faults, either binding a pull-apart basin between the islands of Malta and Gozo or associated with minor connecting antitethic structures. Such a configuration may be responsible for the generation or reactivation of faults onshore and offshore the Maltese Islands, and fits into the modern divergent strain-stress regime inferred from geodetic data

    Active faulting offshore the Maltese Islands revealed by geophysical and geochemical observations

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    The Maltese Islands (central Mediterranean Sea) are intersected by two normal fault systems associated with continental rifting to the south. Because of a lack of evidence for offshore displacement and insignificant historical seismicity, the systems have been considered to be inactive. Here we integrate aerial and marine geological, geophysical and geochemical data to demonstrate that: (i) the majority of faults offshore the Maltese Islands underwent extensional to transtensional deformation during the last 20 ka, (ii) active degassing of CH4 and CO2 occurs via these faults. The gases migrate through Miocene carbonate bedrock and the overlying Plio-Pleistocene sedimentary layers to generate pockmarks at the muddy seafloor and rise through the water column into the atmosphere. We infer that the offshore faults systems are permeable and that they were active recently and simultaneously. The latter can be explained by a transtensional system involving two right-stepping, right-lateral NW-SE trending faults, either binding a pull-apart basin between the islands of Malta and Gozo or associated with minor connecting antitethic structures. Such a configuration may be responsible for the generation or reactivation of faults onshore and offshore the Maltese Islands, and fits into the modern divergent strain-stress regime inferred from geodetic data.peer-reviewe

    SOME PRODUCTION AND NUTRITION PARAMETERS IN VARIOUS SYSTEMS OF COW KEEPING IN EARLY LACTATION

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    Analizirani su proizvodni pokazatelji i utrošak hrane po jedinici proizvoda u dvije grupe od po 26 grla muznih krava, holštajn-frizijske pasmine koje su se telile u siječnju 1989. godine. Ispitivanja su vršena na farmi slobodnog sistema držanja, kapaciteta 1000 grla s instaliranom kompjuterskom opremom za rukovođenje procesima proizvodnje. Životinje su praćene od telenja do 35. dana laktacije. Ogledna grupa je od 6. dana laktacije bila u slobodnom sistemu držanja, dok je kontrolna grupa bila tokom čitavog trajanja ogleda u klasičnoj staji na vezu. Željelo se ustanoviti mogućnost uvoda krava u mlječnost u slobodnom sistemu držanja s hranidbom koncentrata preko automatskih hranilica i mužnjom u izmuzištu, sa automatikom za individualno praćenje proizvodnje. Ustanovljeno je da kompjuterski sistem omogućava uvod krava u mlječnost u slobodnom sistemu držanja,bez negativnih posljedica na proizvodnju, te da se ostvaruje utrošak hrane po jedinici proizvoda isti kao u klasičnoj staji na vezu.Production indicators and food consumption per product unit in two groups of 26 Holstein-Frisian dairy cows calved in January 1989 were analyzed. Investigations were carried out on a free system dairy farm, capacity a 1000 head, with a computer installed to follow\u27 the production processes. The cows were followed from calčvng until 35- day of lactation. The trial group was kept free from the 6rh lactation day hile the control group was kept tied in a traditional shed during the trial period. The aim was to establish a possibility of introducing the cows to being milked in a free system and fed on concentrates by means of automatic feeding system and milked in the milking parlour; each animal as followed by the computer system. It as established that the computer system enabled initiations of cows into milking in the free keeping system without negative effects on production and that the food consumption per production unit as the same as when the cows were kept tied in a traditional shed

    Experts’ consensus on the definition and management of high risk multiple myeloma

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    High risk multiple myeloma (HRMM) at diagnosis is currently recognized according to the Revised International Staging System (R-ISS) which was set up in 2015. Since then, new clinical and biological prognostic factors have been developed, which could implement the definition of High Risk (HR) category. We conducted a survey in order to identify which additional parameters, both clinical and biological, are considered more useful for the clinical practice and to evaluate if the management of Multiple Myeloma (MM) should change on the basis of the risk category. A questionnaire, consisting of 8 statements, was submitted to 6 Italian experts, from the European Myeloma Network (EMN) Research Italy, using the Delphi method. The colleagues were asked to answer each question using a scale between 0 and 100. If a statement did not reach at least 75 out of 100 points from all the participants, it was rephrased on the basis of the proposal of the experts and resubmitted in a second or further round, until a consensus was reached among all. From the first round of the survey a strong consensus was reached regarding the opportunity to revise the R-ISS including chromosome 1 abnormality, TP53 mutation or deletion, circulating plasma cells by next generation flow and extramedullary plasmacytomas. No consensus was reached for the definition of “double hit” MM and for the application in clinical practice of treatment strategies based on the risk category. In the second round of the Delphi questionnaire, “double-hit” MM was recognized by the association of at least two high-risk cytogenetic or molecular abnormalities. Moreover, the experts agreed to reserve an intensified treatment only to specific conditions, such as plasma cell leukaemia or patients with multiple extramedullary plasmacytomas, while they admitted that there are not sufficient real word data in order to modify treatment on the basis of MRD assessment in clinical practice. This survey suggests that the definition of HRMM should be implemented by additional clinical and biological risk factors, that will be useful to guide treatment in the future
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