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SKA (Square Kilometre Array), the largest and most powerful interferometric array of radio telescopes in the world in the 50 MHz to 15 GHz frequency range is currently under construction. Its unprecedented performance will revolutionize modern astrophysics starting from the next decade. The technological radioastronomical group at the INAF-Arcetri Astrophysical Observatory is actively involved in the design, development and validation of SKA-Low, the low-frequency (50-350 MHz) component of SKA. Keywords. SKA, radio telescopes, aperture arrays, calibration. SKA (Square Kilometre Array), la più estesa e potente rete interferometrica di radiotelescopi al mondo nella banda di frequenze da 50 MHz a 15 GHz, è attualmente in fase di costruzione. A partire dal prossimo decennio, le prestazioni senza precedenti di SKA rivoluzioneranno l'astrofisica moderna. Il gruppo tecnologico di radioastronomia dell'Osservatorio Astrofisico di Arcetri (INAF) contribuisce attivamente alle fasi di design, sviluppo e validazione di SKA-Low, la componente di SKA operante a bassa frequenza (50-350 MHz). Parole chiave. SKA, radiotelescopi, array di aperture, calibrazione.

SKA (Square Kilometre Array), the largest and most powerful interferometric array of radio telescopes in the world in the 50 MHz to 15 GHz frequency range is currently under construction. Its unprecedented performance will revolutionize modern astrophysics starting from the next decade. The technological radioastronomical group at the INAF-Arcetri Astrophysical Observatory is actively involved in the design, development and validation of SKA-Low, the low-frequency (50-350 MHz) component of SKA.

The low-frequency radio telescope of the Square Kilometre Array (SKA-Low), currently under construction in the remote Murchison shire in the Western Australia's outback, will observe the sky between 50 MHz and 350 MHz with unprecedented sensitivity and stringent requirements for polarization accuracy. In this work, we investigate the instrumental polarization purity of a SKA-Low prototype station by means of the Intrinsic Cross-Polarization Ratio (IXR) figure of merit. We derive all-sky experimental IXR maps using data from the Aperture Array Verification System 2 (AAVS2). The results are presented at three frequencies within the SKA-Low bandwidth (110, 160, and 230 MHz) with a quantitative comparison between observed and simulated all-sky IXR maps. Our findings show good agreement in IXR map distributions and promising consistency in their radial profiles, meeting SKA-Low's IXR specification overall. This study offers an empirical approach to verifying SKA-Low's polarization performance using all-sky observations from individual stations and will potentially support the telescope's early science commissioning phase.

In two series of measurements, Cardone, Carpinteri et al. report an excess of neutrons over the background flux corresponding to the catastrophic fracture of a granite block subject to compression. Here we show that these measurements contain large inconsistencies with respect to the stated experimental procedure, including fractional neutron counts and strongly non Poissonian statistics

The low frequency component of the Square Kilometre Array (SKA1-Low) will be an aperture phased array located at the Murchison Radio-astronomy Observatory (MRO) site in Western Australia. It will be composed of 512 stations, each of them consisting of 256 log-periodic dual polarized antennas, and will operate in the low frequency range (50 MHz - 350 MHz) of the SKA bandwidth. The Aperture Array Verification System 2 (AAVS2), operational since late 2019, is the last full-size engineering prototype station deployed at the MRO site before the start of the SKA1-Low construction phase. The aim of this paper is to characterize the station performance through commissioning observations at six different frequencies (55, 70, 110, 160, 230 and 320 MHz) collected during its first year of activities. We describe the calibration procedure, present the resulting all-sky images and their analysis, and discuss the station calibratability and system stability. Using the difference imaging method, we also derive estimates of the SKA1-Low sensitivity for the same frequencies, and compare them to those obtained through electromagnetic simulations across the entire telescope bandwidth, finding good agreement (within \\(\\leq 13%\\)). Moreover, our estimates exceed the SKA1-Low requirements at all the considered frequencies, by up to a factor of \\(\\sim\\)2.3. Our results are very promising and allow an initial validation of the AAVS2 prototype station performance, which is an important step towards the upcoming SKA-Low telescope construction and science.

For the first time, a multiplanar photonic crystal structure has been obtained using cellulose as a structural material. This all-polymer system, made of cellulose, polyvinyl alcohol and poly( N -vinylcarbazole) is a ternary planar photonic crystal composed by 7 repeated trilayers produced by spin coating. Trimethylsilyl cellulose is used as a precursor to be converted to cellulose. Transverse Transmission Electron Microscopy analysis of our systems confirms the multilayered structure whose optical response can be theoretically accounted for. Preliminary results on the response of the photonic crystal to water vapors envisage the use of this system for humidity optical sensing.

Background In a group of children admitted to the paediatric intensive care unit (PICU) receiving continuous kidney replacement therapy (CKRT), we aim to evaluate the data about their hemodynamic, ventilation and analgo-sedation profile in the first 24 h of treatment and possible associations with mortality. Methods Retrospective cohort study of children admitted to the PICU of the University Hospital of Padova undergoing CKRT between January 2011 and March 2021. Data was collected at baseline (T 0 ), after 1 h (T 1 ) and 24 h (T 24 ) of CKRT treatment. The differences in outcome measures were compared between these time points, and between survivors and non-survivors. Results Sixty-nine patients received CKRT, of whom 38 (55%) died during the PICU stay. Overall, the vasoactive inotropic score and the adrenaline dose increased at T 1 compared to T 0 ( p  = 0.012 and p  = 0.022, respectively). Compared to T 0 , at T 24 patients showed an improvement in the following ventilatory parameters: Oxygenation Index ( p  = 0.005), Oxygenation Saturation Index ( p  = 0.013) PaO 2 /FiO 2 ratio ( p  = 0.005), SpO 2 /FiO 2 ratio ( p  = 0.002) and Mean Airway Pressure ( p  = 0.016). These improvements remained significant in survivors ( p  = 0.01, p = 0.027, p  = 0.01 and p  = 0.015, respectively) but not in non-survivors. No changes in analgo-sedative drugs have been described. Conclusions CKRT showed a significant impact on hemodynamics and ventilation in the first 24 h of treatment. We observed a significant rise in the inotropic/vasoactive support required after 1 h of treatment in the overall population, and an improvement in the ventilation parameters at 24 h only in survivors. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information

Volatile organic compounds are a class of widespread air pollutants that are increasingly impacting anthropized environments. Due to the potential toxic effects associated with many of these compounds, the development of inexpensive and effective sensors for in situ detection, both indoor and outdoor, is of paramount technological importance to mitigate human exposure and develop appropriate intervention strategies. However, portable technologies are typically designed to quantify known pollutants, while qualitative measurements often require complex sampling and laboratory analyses. In this study, we propose a dual‐detection photonic sensor based on polymeric microcavities doped with emitting nanocrystals, capable of identifying various volatile compounds in vapor phase. The sensor consists of a lattice of altenated sub‐micrometric layers of cellulose acetate and poly(N‐vinylcarbazole), with a periodic structure interrupted by an engineered defect layer doped with core‐shell CdSe/ZnS quantum dots. The response to different analytes can be detected through both transmittance and photoluminescence measurements, with distinct features arising from the specific chemical and physical interactions between the sensor components and the pollutants. Volatile organic compounds are harmful air pollutants requiring efficient detection. This study presents a dual‐detection distributed Bragg reflector‐based sensor using polymeric microcavities and quantum dots to identify pollutants via transmittance and photoluminescence. The portable sensor offers qualitative analysis of various compounds in vapor phase, enabling real‐time monitoring in both indoor and outdoor environments.

PurposeThe aim of this study was to estimate the proportion of bleedings that occurred among warfarin users attributable to the concomitant use of other medications. A general approach for measuring the impact of the prescriptive inappropriateness on drug adverse outcomes at the population level is described.MethodsA meta-analysis was conducted to obtain summary relative risks of bleeding associated with concurrent use of warfarin and other medications compared to warfarin use alone. A population-based investigation was performed, in an Italian cohort of cardiopathic patients aged 65 years or older, to estimate the prevalence of concurrent users of warfarin and other medicaments. The population attributable fraction was computed by combining data on summary relative risks and prevalence of concurrent users.ResultsConcomitant use of warfarin and cotrimoxazole, amiodarone, quinolones, macrolides, platelet aggregation inhibitors, SSRIs, NSAIDs, and lipid-lowering agents was associated with an increased risk of bleeding. The corresponding attributable fractions were 3% (95% CI 2 to 4%), 21% (1 to 41%), 21% (17 to 25%), 9% (8 to 10%), 14% (12 to 16%), 6% (5 to 8%), 10% (1 to 20%), and 8% (0 to 18%), respectively.ConclusionsMore than half of bleeding events occurring among frail elderly using warfarin are attributable to a concomitant use of warfarin with certain drugs. Because some of these drugs appear to be essential for the treatment/prevention of cardiovascular conditions, and their concomitant use with warfarin could be acceptable in some cases, proper INR-monitoring and warfarin dose adjustments are requested.

Background Healthcare utilization data are increasingly used for chronic disease surveillance. Nevertheless, no standard criteria for estimating prevalence of high-impact diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, are available. In this study an algorithm for recognizing COPD/asthma cases from HCU data is developed and implemented in the HCU databases of the Italian Lombardy Region (about 10 million residents). The impact of diagnostic misclassification for reliably estimating prevalence was also assessed. Methods Disease-specificdrug codes, hospital discharges together with co-payment exemptions when available, and a combination of them according with patient’s age, were used to create the proposed algorithm. Identified cases were considered for prevalence estimation. An external validation study was also performed in order to evaluate systematic uncertainty of prevalence estimates. Results Raw prevalence of COPD and asthma in 2010 was 3.6 and 3.3% respectively. According to external validation, sensitivity values were 53% for COPD and 39% for asthma. Adjusted prevalence estimates were respectively 6.8 and 8.5% for COPD (among person aged 40 years or older) and asthma (among person aged 40 years or younger). Conclusions COPD and asthma prevalence may be estimated from HCU data, albeit with high systematic uncertainty. Validation is recommended in this setting.