6,923 research outputs found

    Towards a plug&play solution for real-time precise positioning on mass-market devices

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    Despite pedestrian and vehicle navigation are the key applications enabled by the development of GNSS technology, the best approach to obtain accurate, reliable, continuous and robust PVT (Position-Velocity-Timing) solutions for this purpose has yet to be identified. The real limiting factor is the environment in which the users usually navigate: e.g. multipath effects and cycle slips in harsh urban environments strongly affect, respectively, pseudorange measurements and the continuity of carrier-phase observations. Therefore, positioning services relying on code-based algorithms cannot always meet the required accuracy - which varies depending on the targeted use case -; on the other hand, phase-based approaches as Real-Time Kinematic (RTK) and Precise Point Positioning (PPP) require strong effort to deal with the ambiguity term and its reinitialization when cycle slips occur. These problems are amplified when GNSS measurements from Android smartphone are considered due to the low-cost, linearly polarized and multi-purpose antenna which inevitably impacts on the quality of GNSS observables. This paper focuses on the performance analysis of GNSS POWER - an algorithm based on the loosely coupling between Single Point Positioning (SPP) solutions and variometric velocity - combined with IGS SSR corrections to increase the accuracy achievable in a real-time stand-alone solution. The integration of SSR corrections within GNSS POWER algorithm is validated in both static and kinematic scenarios using high-end GNSS receivers and Andorid smartphones. The results demonstrated the advantages of using SSR corrections on SPP and GNSS POWER solutions also on Android devices opening to new applications of real-time stand-alone positioning approaches on mass-market devices

    comparison of breast muscle traits and meat quality characteristics in 2 commercial chicken hybrids

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    Abstract A trial was conducted to compare muscle traits and meat quality characteristics of the pectoralis muscle in 2 chicken commercial hybrids having standard (SBY) and high breast yield (HBY), respectively. A total of 2,124 one-day-old male chicks, equally divided into 2 experimental groups represented by strains (SBY and HBY), were grown using homogenous conditions and fed the same standard diets until reaching live weight of 4.2 kg at 53 and 55 d for the SBY and HBY groups, respectively. Thirty-six birds per each genotype were randomly selected, and their pectoralis major muscles were used to assess meat quality properties (color attributes, pH, drip loss, cook loss, Allo-Kramer shear values after cooking, moisture, proteins, total lipids, and ashes) as well as histological traits (cross-sectional area, frequency of abnormal fibers, and intramuscular fat infiltration). As expected, HBY genotype had higher breast yield (31.0 vs. 30.0%; P ≤ 0.05). Histological evaluations showed that HBY pectoralis muscles had higher cross-sectional fiber area coupled with a dramatically higher (P ≤ 0.001) incidence of abnormal fibers and more abundant infiltration of intramuscular fat. Moreover, histopathological anomalous features such as central nuclei, proliferation of endomysial and perimysial collagen, inflammatory infiltrate, and necrosis of the fibers were also observed. As for meat quality, SBY hybrid showed lower ultimate pH values (5.97 vs. 6.07; P ≤ 0.01), whereas overall color parameters were not affected by genotype. Breast meat from the HBY genotype also exhibited significantly lower ability to retain liquid during refrigerated storage (drip loss, 2.46 vs. 2.06%; P ≤ 0.05) and cooking (26.2 vs. 21.1%; P ≤ 0.05) as well as higher shear-force values (2.59 vs. 2.11 kg/g; P ≤ 0.001). Finally, with regard to chemical composition, significant differences (P ≤ 0.05) were detected in protein (22.8 vs. 23.5%) and lipid (1.65 vs. 1.82%) contents, which were significantly lower in the HBY hybrid, whereas moisture content tended (P = 0.07) to be inferior in the SBY hybrid

    Indirect Self-Modulation Instability Measurement Concept for the AWAKE Proton Beam

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    AWAKE, the Advanced Proton-Driven Plasma Wakefield Acceleration Experiment, is a proof-of-principle R&D experiment at CERN using a 400 GeV/c proton beam from the CERN SPS (longitudinal beam size sigma_z = 12 cm) which will be sent into a 10 m long plasma section with a nominal density of approx. 7x10^14 atoms/cm3 (plasma wavelength lambda_p = 1.2mm). In this paper we show that by measuring the time integrated transverse profile of the proton bunch at two locations downstream of the AWAKE plasma, information about the occurrence of the self-modulation instability (SMI) can be inferred. In particular we show that measuring defocused protons with an angle of 1 mrad corresponds to having electric fields in the order of GV/m and fully developed self-modulation of the proton bunch. Additionally, by measuring the defocused beam edge of the self-modulated bunch, information about the growth rate of the instability can be extracted. If hosing instability occurs, it could be detected by measuring a non-uniform defocused beam shape with changing radius. Using a 1 mm thick Chromox scintillation screen for imaging of the self-modulated proton bunch, an edge resolution of 0.6 mm and hence a SMI saturation point resolution of 1.2 m can be achieved.Comment: 4 pages, 4 figures, EAAC conference proceeding

    Late Quaternary monogenetic volcanoes along Río Salado, Sothwest Mendoza Province, Argentina

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    On the eastem flank of the Andes, to the north of Río Salado in southwest Mendoza Province (35º07'S-35º10'S), there are 4 monogenetic cones with blocky lava flows. A western group of small volcanoes, Hoyada, Lagunita and Loma Negra, with a total volume of -0.2 km3, are composed of amphibole-bearing basaltic andesite, and the eastem, more voluminous Hoyo Colorado volcano, with 0.44 km3 is composed of olivine (+ oxidised amphibole) basaltic andesite. Although data indicate they were emitted through successive, strombolian eruptions, they are overall coeval and the youngest Late Pleistocene volcanoes located in an "extra-Andean" setting, -70 km east of the main volcanic front. The magmas of the westem group of monogenetic cones show petrographic and geochemical characteristics that support processes of crustal interaction during ascent. In contrast, the magmas of the Hoyo Colorado volcano had a more direct ascent. Structural characteristics of the basement rocks to the volcanoes and the current seismotectonic activity of the Andes at this latitude indicate that the monogenetic cones of Río Salado were emplaced in a dominantly compressive tectonic regime

    Group theory analysis of electrons and phonons in N-layer graphene systems

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    In this work we study the symmetry properties of electrons and phonons in graphene systems as function of the number of layers. We derive the selection rules for the electron-radiation and for the electron-phonon interactions at all points in the Brillouin zone. By considering these selection rules, we address the double resonance Raman scattering process. The monolayer and bilayer graphene in the presence of an applied electric field are also discussed.Comment: 8 pages, 6 figure

    Low mass dimuons within a hybrid approach

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    We analyse dilepton emission from hot and dense hadronic matter using a hybrid approach based on the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) transport model with an intermediate hydrodynamic stage for the description of heavy-ion collisions at relativistic energies. Focusing on the enhancement with respect to the contribution from long-lived hadron decays after freeze-out observed at the SPS in the low mass region of the dilepton spectra (often referred to as "the excess"), the relative importance of the emission from the equilibrium and the non-equilibrium stages is discussed.Comment: Proceedings of Hot Quarks 2010, 21-26 June 2010 Las Londe Les Maures; v2: Corrected typos and added a commen

    A complete fos approach for indoor crowdsourced mapping. Case study on Sapienza University of Rome faculties

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    Indoor mapping is an essential process in several applications such as the visualization of space and its utilization, security and resource planning, emergency planning and location-based alerts and, last but not least, indoor navigation. In this work, a completely free and open-source (FOS) approach to map indoor environments, and to navigate through them, is presented. Our tests were carried out within Sapienza University of Rome public buildings; in detail, Letters and Philosophy faculty and Engineering faculty indoor environments were mapped. To reach this goal, only open source software such as Quantum GIS (QGIS) and open-source platforms like Open Street Map (OSM) and its indoor viewer, Open Level Up (OLU) were adopted. A database of indoor environments of the two faculties, completely compatible with OLU, was created through QGIS. In this way, a public territorial information system of classrooms, offices and laboratories is accessible to everyone who can, hence, add or modify the information, following the principle of crowdsourcing and of Volunteered Geographic Information (VGI). The developed procedure is now standard and its outputs accepted by the OSM community. Hence, the long-term developments of this project are the proposal for the volunteered and cooperative indoor mapping and design of strategic buildings and infrastructures (hospitals, schools, public offices, shopping centers, stations, airports etc.), starting from the available information (indoor layouts) and knowledge acquired through experience of people who normally work inside them and/or visit them frequently. In this context it is possible to state that the development of VGI for internal maps for strategic buildings, infrastructures and denied GNSS environments, not only supports and improves internal and external navigation without interruption, but can also have a significant positive impact on security and emergency management

    CENTIMETER COSMO-SKYMED RANGE MEASUREMENTS FOR MONITORING GROUND DISPLACEMENTS

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    The SAR (Synthetic Aperture Radar) imagery are widely used in order to monitor displacements impacting the Earth surface and infrastructures. The main remote sensing technique to extract sub-centimeter information from SAR imagery is the Differential SAR Interferometry (DInSAR), based on the phase information only. However, it is well known that DInSAR technique may suffer for lack of coherence among the considered stack of images. New Earth observation SAR satellite sensors, as COSMO-SkyMed, TerraSAR-X, and the coming PAZ, can acquire imagery with high amplitude resolutions too, up to few decimeters. Thanks to this feature, and to the on board dual frequency GPS receivers, allowing orbits determination with an accuracy at few centimetres level, the it was proven by different groups that TerraSAR-X imagery offer the capability to achieve, in a global reference frame, 3D positioning accuracies in the decimeter range and even better just exploiting the slant-range measurements coming from the amplitude information, provided proper corrections of all the involved geophysical phenomena are carefully applied. The core of this work is to test this methodology on COSMO-SkyMed data acquired over the Corvara area (Bolzano – Northern Italy), where, currently, a landslide with relevant yearly displacements, up to decimeters, is monitored, using GPS survey and DInSAR technique. The leading idea is to measure the distance between the satellite and a well identifiable natural or artificial Persistent Scatterer (PS), taking in account the signal propagation delays through the troposphere and ionosphere and filtering out the known geophysical effects that induce periodic and secular ground displacements. The preliminary results here presented and discussed indicate that COSMO-SkyMed Himage imagery appear able to guarantee a displacements monitoring with an accuracy of few centimetres using only the amplitude data, provided few (at least one) stable PS's are available around the monitored area, in order to correct residual biases, likely due to orbit errors

    Subthalamic neural activity patterns anticipate economic risk decisions in gambling

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    Economic decision-making is disrupted in individuals with gambling disorder, an addictive behavior observed in Parkinson’s Disease (PD) patients receiving dopaminergic therapy. The subthalamic nucleus (STN) is involved in the inhibition of impulsive behaviors; however its role in impulse control disorders and addiction is still unclear. Here, we recorded STN local field potentials (LFPs) in PD patients with and without gambling disorder during an economic decision-making task. Reaction times analysis showed that for all patients the decision whether to risk preceded task onset. We compared then for both groups the STN LFP preceding high and low risk economic decisions. We found that risk avoidance in gamblers correlated with larger STN LFP low frequency (<12 Hz) fluctuations preceding task onset. In particular, the amplitude of low frequency LFP fluctuations carried significant information about future decisions. Decisions of patients not affected by gambling disorder were instead not correlated with pre-task STN LFP. Our results suggest that STN activity preceding task onset affects risk decisions by pre-emptively inhibiting attraction to high but unlikely rewards in favor of a long-term payoff
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