1,797 research outputs found

    Hybrid UWB-Inertial TDoA-based Target Tracking with Concentrated Anchors

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    In this paper, hybrid radio/inertial mobile target tracking for accurate and smooth path estimation is considered. The proposed tracking approach builds upon an Ultra WideBand (UWB)-based positioning algorithm, based on the Linear Hyperbolic Positioning System (LinHPS), with Time Difference of Arrival (TDoA) processing and anchors concentrated on a single hotspot at the center of the environment where the target moves. First, we design an Adaptive Radio-based Extended Kalman Filter (AREKF), which does not require a priori statistical knowledge of the noise in the target movement model and estimates the measurement noise covariance, at each sampling time, according to a proper LookUp Table (LUT). In order to improve the performance of AREKF, we incorporate inertial data collected from the target and propose three “hybrid” radio/inertial algorithms, denoted as Hybrid Inertial Measurement Unit (IMU)-aided Radio-based EKF (HIREKF), Hybrid Noisy Control EKF (HNCEKF), and Hybrid Control EKF (HCEKF). Our results on experimentally acquired paths show that the proposed algorithms achieve an average instantaneous position estimation error on the order of a few centimeters. Moreover, the minimum target path length estimation error, obtained with HCEKF, is on the order of 6% and 1% for two paths with lengths equal to approximately 17 m and 46 m, respectively

    ASTRI SST-2M prototype and mini-array simulation chain, data reduction software, and archive in the framework of the Cherenkov Telescope Array

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    The Cherenkov Telescope Array (CTA) is a worldwide project aimed at building the next-generation ground-based gamma-ray observatory. Within the CTA project, the Italian National Institute for Astrophysics (INAF) is developing an end-to-end prototype of the CTA Small-Size Telescopes with a dual-mirror (SST-2M) Schwarzschild-Couder configuration. The prototype, named ASTRI SST-2M, is located at the INAF "M.C. Fracastoro" observing station in Serra La Nave (Mt. Etna, Sicily) and is currently in the scientific and performance validation phase. A mini-array of (at least) nine ASTRI telescopes has been then proposed to be deployed at the Southern CTA site, by means of a collaborative effort carried out by institutes from Italy, Brazil, and South-Africa. The CTA/ASTRI team is developing an end-to-end software package for the reduction of the raw data acquired with both ASTRI SST-2M prototype and mini-array, with the aim of actively contributing to the global ongoing activities for the official data handling system of the CTA observatory. The group is also undertaking a massive Monte Carlo simulation data production using the detector Monte Carlo software adopted by the CTA consortium. Simulated data are being used to validate the simulation chain and evaluate the ASTRI SST-2M prototype and mini-array performance. Both activities are also carried out in the framework of the European H2020-ASTERICS (Astronomy ESFRI and Research Infrastructure Cluster) project. A data archiving system, for both ASTRI SST-2M prototype and mini-array, has been also developed by the CTA/ASTRI team, as a testbed for the scientific archive of CTA. In this contribution, we present the main components of the ASTRI data handling systems and report the status of their development.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Bexco, Busan, Korea. All CTA contributions at arXiv:1709.0348

    DETERMINAZIONE INNOVATIVA DEL ROTENONE NEGLI OLI DI OLIVA DA AGRICOLTURA BIOLOGICA MEDIANTE SPETTROMETRIA DI MASSA TANDEM

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    Il rotenone, pesticida naturale utilizzato in agricoltura biologica su una grande varietĂ  di colture, Ăš stato determinato quantitativamente mediante Atmosheric Pressure Chemical Ionisation Spettrometria di Massa Tandem (APCI MS/MS) nelle olive e negli oli di oliva ottenuti dopo trattamento in una prova di campo che ha interessato la cv Carolea in Calabria. La tecnica analitica ha previsto la realizzazione di esperimenti “Multiple Reaction Monitoring” (MRM) utilizzando uno standard interno ottenuto per sintesi. Le quantitĂ  rilevate sono comprese tra 9 mg/Kg di olio dopo 1 giorno dal trattamento e 0.15 mg/Kg di olio dopo 1 mese circa dal trattamento. Quest’ultimo valore Ăš molto piĂč elevato dei 40 ”g/Kg permessi dalla legislazione italiana

    NuSTAR and multifrequency study of the two high-redshift blazars S5 0836+710 and PKS 2149-306

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    The most powerful blazars are the flat spectrum radio quasars whose emission is dominated by a Compton component peaking between a few hundred keV and a few hundred MeV. We selected two bright blazars, PKS 2149-306 at redshift z=2.345 and S5 0836+710 at z=2.172, in order to observe them in the hard X-ray band with the NuSTAR satellite. In this band the Compton component is rapidly rising almost up to the peak of the emission. Simultaneous soft-X-rays and UV-optical observations were performed with the Swift satellite, while near-infrared (NIR) data were obtained with the REM telescope. To study their variability, we repeated these observations for both sources on a timescale of a few months. While no fast variability was detected during a single observation, both sources were found to be variable in the X-ray band, up to 50%, between the two observations, with larger variability at higher energies. No variability was detected in the optical/NIR band. These data together with Fermi-LAT, WISE and other literature data are then used to study the overall spectral energy distributions (SEDs) of these blazars. Although the jet non-thermal emission dominates the SED, it leaves the UV band unhidden, allowing us to detect the thermal emission of the disc and to estimate the mass of the black hole. The non-thermal emission is well reproduced by a one-zone leptonic model. The non-thermal radiative processes are synchrotron, self-Compton and external Compton using seed photons from both the broad-line region (BLR) and the torus. We find that our data are better reproduced if we assume that the location of the dissipation region of the jet, R_diss, is in-between the torus, (at R_torus), and the BLR (R_torus>R_diss>R_BLR). The observed variability is explained by changing a minimum number of model parameters by a very small amount.Comment: 11 pages, 5 figures, accepted for publication in Ap

    GRB051210: Swift detection of a short gamma ray burst

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    The short/hard GRB051210 was detected and located by the Swift-BAT instrument and rapidly pointed towards by the narrow field instrumens. The XRT was able to observe a bright X-ray afterglow, one of the few ever observed for this class of bursts. We present the analysis of the prompt and afterglow emission of this event The BAT spectrum is a power-law with photon index 1.1 +/-0.3. The X-ray light curve decays with slope 2.58+/-0.11 and shows a small flare in the early phases. The spectrum can be described with a power law with photon index 1.54+/-0.16 and absorption (7.5 (-3.2, +4.3)*10^20 cm-2 We find that the X-ray emission is consistent with the hypothesis that we are observing the curvature effect of a GRB occurred in a low density medium, with no detectable afterglow. We estimate the density of the circumburst medium to be lower than 4*10^-3 cm^-3. We also discuss different hypothesis on the possible origin of the flare.Comment: 5 pages, 3 figures, submitted to A&A Letter

    The Impact of COVID-19 on doctors well-being: Results of a web survey during the lockdown in Italy

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    OBJECTIVE: On March 12, 2020, the World Health Organization (WHO) declared the outbreak of a new Coronavirus disease (COVID-19), to be a pandemic. From the be- ginning, Italy (in particular the Northern re- gions) was the first large European country to be hit and one of the most affected coun- tries worldwide. This had a significant impact on the workload and psychological health of health workers. The aim of this web-based cross-sectional study is to assess the con- sequences of the COVID-19 pandemic on Ital- ian doctors’ well-being and psychological dis- tress, in respect of demographic and occu- pational characteristics, lifestyle and habits during the lockdown period.PATIENTS AND METHODS: We conducted a web-based cross-sectional survey based on Google¼ Forms to collect data. The participa- tion was available during the lockdown period that started in Italy on March 9, 2020 and it was voluntary and anonymous. The question- naire explored demographic and occupational variables, lifestyle and habits during the lock- down, perceived well-being and psychological distress. Multivariate logistic regression models were fitted. RESULTS: Our study reported the very alarm- ing psychological conditions of Italian doctors, especially among those who worked in the most affected regions, where a level of psychological distress of 93.8% and poor well-being of 58.9% were registered. These percentages were even higher in the case of female hospital workers with low job seniority, and those caring for COVID-19 patients. CONCLUSIONS: Our findings reported a sig- nificant psychosocial impact of the COVID-19 outbreak on Italian doctors, particularly among those working in the most affected regions of the country. Further studies are necessary to better understand the effects of the COVID-1

    Aetiology of pneumonia following isolated closed head injury

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    AbstractPatients undergoing mechanical ventilation (MV) after an isolated closed head injury (ICHI) have often been found to develop hospital-acquired pneumonia (HAP) well before subjects who require MV for different reasons. In a prospective study of patients receiving MV after an ICHI, 38 subjects (out of 65 with clinically suspected HAP) had a bacteriological diagnosis established on the basis of correspondence between cultures made from bronchoalveolar lavage and protected specimen brush (with quantitative thresholds of 104 and 103 cfu ml−1, respectively). Patients were separated according to the time of onset of HAP, with 20 subjects who developed HAP within 4 days of the start of MV (early onset pneumonia, EOP) and 18 subjects who developed HAP after the fourth day (late onset pneumonia, LOP). In those who had LOP, an expected spectrum of organisms was found, with Gram-negatives (especially Pseudomonas sp.) accounting for the majority of isolates. However, in EOP cases, Gram-positive bacteria (especially Staphylococcus sp. and Streptococcus pneumoniae) were found to largely predominate (P = 0·0000026). This confirms the high incidence of staphylococcal pneumonia in neurosurgery patients, and also provides evidence that the vast majority of such staphylococcal pneumonia are EOP. Unlike most previous reports, the microbiological findings from the present study suggest that a cut-off point of 4 days successfully distinguishes between EOP and LOP. Since these two clinical entities differ significantly in terms of pathogenesis and aetiology, preventive measures and therapeutical protocols have to be tailored accordingly

    A Microchip Integrated Sensor for the Monitoring of High Concentration Photo-voltaic Solar Modules

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    Abstract A CMOS sensor fabricated in 0.35ÎŒm technology, specifically designed for the monitoring of High Concentration Photo-Voltaic (HCPV) modules, is presented. The microchip was designed to monitor temperature and illumination of each solar cell in a module. Temperature is measured by monitoring the base-emitter voltage of two coupled, diode connected, bipolar transistors, while the illumination sensor is an integrated p-n junction photodiode. A custom communication protocol is implemented in the chip to allow the sharing of a two-wire communication resource among the cells
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