557 research outputs found

    Renewed activity from the magnetar CXOU J164710.2-455216

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    On 2018 February 5 at 19:27:11 UT, Swift BAT detected a new burst from a direction consistent with the magnetar CXOU J164710.2-455216 (trigger=808755; Barthelmy et al. 2018, GCN #22389)

    Validity and usability of a smart ball–driven serious game to monitor grip strength in independent elderlies

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    Telemonitoring is one of the most expedient answers to the strong need for preventive care imposed by the rapidly aging society. We propose an innovative solution to the detection of early signs of frailty by presenting a serious game controlled by a smart sensorized soft plastic ball, designed to achieve continuous home-based monitoring of muscle weakness in older adults. Design, development, and testing of the smart ball and of the game interface devised to guide the monitoring procedure are presented. Reliability and concurrent validity of the system in measuring maximal grip strength against the clinical standard Jamar\uae were evaluated. Serious game usability and acceptance were investigated on 26 elderlies. Smart ball and Jamar measurements were well correlated (0.76 and 0.80 for dominant and non-dominant hands) and test\u2013retest reliability of pressure measurements was excellent (intraclass correlation coefficient >0.94). The serious game was well accepted by the 96.1 percent of participants, who provided a strongly positive usability score (87.7/100). The smart ball\u2013driven serious game demonstrated excellent reliability and good validity in measuring grip strength. The proposed smart ball\u2013driven serious game can be used for home self-monitoring of grip strength in elderlies

    Diffusive transport of light in two-dimensional granular materials

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    We study photon diffusion in a two-dimensional random packing of monodisperse disks as a simple model of granular material. We apply ray optics approximation to set up a persistent random walk for the photons. We employ Fresnel's intensity reflectance with its rich dependence on the incidence angle and polarization state of the light. We present an analytic expression for the transport-mean-free path in terms of the refractive indices of grains and host medium, grain radius, and packing fraction. We perform numerical simulations to examine our analytical result.Comment: 9 pages, 3 figure

    Effect of two different source of forage on the organic matter digestibility in Mediterranean Italian Buffalo cows

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    The present study aimed to evaluate the influence of two different source of forage (haysilage and hay) during the lactation on organic matter digestibility (OMD) in buffalo cows. Lactating buffaloes (n = 40) at 29.6 days in milk (DIM) were equally divided as function of previous milk yield into Group 1 (meadow hay, n = 20) and Group 2 [haysilage (Lolium multiflorum), n = 20]. The diets were isoenergetic [0.92 milk unit forage (MUF) on dry matter basis] and isoproteic (16.2 % crude protein on dry matter basis) and administred as total mixed ration (TMR). From all the buffaloes, for each group and in two sampling time (first sampling, DIM = 74.0 and second sampling, DIM = 129.0) the faeces were collected in order to evaluate the in vivo digestibility. Overall the trial, the subjects fed haysilage showed higher OMD than those fed hay (66.1 vs 45.7; P<0.01), moreover the in vivo digestibility was affected by the DIM, in particular in the group fed hay (40.6 vs 53.4; P<0.0001, respectively). This work underlines the importance of the administration of the haysilage (Lolium multiflorum) as source of high quality forage because it gives, overall the lactation, more nutritive principles compared with meadow hay

    Using Virtual Reality to Rehabilitate Neglect

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    Purpose: Virtual Reality (VR) platforms gained a lot of attention in the rehabilitation field due to their ability to engage patients and the opportunity they offer to use real world scenarios. As neglect is characterized by an impairment in exploring space that greatly affects daily living, VR could be a powerful tool compared to classical paper and pencil tasks and computer training. Nevertheless, available platforms are costly and obstructive. Here we describe a low cost platform for neglect rehabilitation, that using consumer equipments allows the patient to train at home in an intensive fashion. Method: We tested the platform on IB, a chronic neglect patient, who did not benefit from classical rehabilitation. Results: Our results show that IB improved both in terms of neglect and attention. Importantly, these ameliorations lasted at a follow up evaluation 5 months after the last treatment session and generalized to everyday life activities. Conclusions: VR platforms built using equipment technology and following theoretical principles on brain functioning may induce greater ameliorations in visuo-spatial deficits than classical paradigms possibly thanks to the real world scenarios in association with the "visual feedback" of the patient's own body operating in the virtual environmen

    Electrospun Conjugated Polymer/Fullerene Hybrid Fibers: Photoactive Blends, Conductivity through Tunnelling-AFM, Light-Scattering, and Perspective for Their Use in Bulk-Heterojunction Organic Solar Cells

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    Hybrid conjugated polymer/fullerene filaments based on MEH-PPV/PVP/PCBM are prepared by electrospinning, and their properties assessed by scanning electron, atomic and lateral force, tunnelling, and confocal microscopy, as well as by attenuated total reflection Fourier transform-infrared spectroscopy, photoluminescence quantum yield and spatially-resolved fluorescence. Highlighted features include ribbon-shape of the realized fibers, and the persistence of a network serving as a template for heterogeneous active layers in solar cell devices. A set of favorable characteristics is evidenced in this way in terms of homogeneous charge transport behavior and formation of effective interfaces for diffusion and dissociation of photogenerated excitons. The interaction of the organic filaments with light, exhibiting specific light-scattering properties of the nanofibrous mat, might also contribute to spreading incident radiation across the active layers, thus potentially enhancing photovoltaic performance. This method might be applied to other electron donor-electron acceptor material systems for the fabrication of solar cell devices enhanced by nanofibrillar morphologies embedding conjugated polymers and fullerene compounds.Comment: 35 pages, 9 figure

    The X-ray outburst of the Galactic Center magnetar over six years of Chandra observations

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    The magnetar SGR J1745-2900 discovered at parsecs distance from the Milky Way central black hole, Sagittarius A*, represents the closest pulsar to a supermassive black hole ever detected. Furthermore, its intriguing radio emission has been used to study the environment of the black hole, as well as to derive a precise position and proper motion for this object. The discovery of SGR J1745-2900 has opened interesting debates about the number, age and nature of pulsars expected in the Galactic center region. In this work, we present extensive X-ray monitoring of the outburst of SGR J1745-2900 using the Chandra X-ray Observatory, the only instrument with the spatial resolution to distinguish the magnetar from the supermassive black hole (2.4" angular distance). It was monitored from its outburst onset in April 2013 until August 2019, collecting more than fifty Chandra observations for a total of more than 2.3 Ms of data. Soon after the outburst onset, the magnetar emission settled onto a purely thermal emission state that cooled from a temperature of about 0.9 to 0.6 keV over 6 years. The pulsar timing properties showed at least two changes in the period derivative, increasing by a factor of about 4 during the outburst decay. We find that the long-term properties of this outburst challenge current models for the magnetar outbursts.Comment: 11 pages, 6 figures. Accepted by Ap
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