Time-Transfer and Clock-Synchronization Technique for Microsatellites in the Lunar Region

The growing number of scientific and commercial missions to the Moon surface poses the need for a dedicated communication and navigation infrastructure. A precise Positioning, Navigation and Timing (PNT) service is a key technology to allow lunar assets to determine their position and velocity, to plan and execute maneuvers and to maintain time. Argotec is working on ANDROMEDA, an end-to-end Communication and Navigation service for users on the Moon surface and in Low Lunar Orbit, based on a constellation of 24 microsatellites operating in high-elliptical frozen orbits around the Moon. To support missions with Communication and Navigation capabilities, an accurate on-board frequency reference and a time-transfer technique are crucial technologies. This paper presents a trade-off analysis of different time-transfer techniques, including existing GNSS, Two-Way Pseudo-Noise ranging, Network Time Protocol, Two Way Satellite Time and Frequency Transfer and Optical links. Furthermore, an additional investigation on crucial constraints on microsatellites' design is performed with the goal of choosing the most suitable time-transfer technique and frequency reference for a microsatellite platform. A Two-Way coherent time transfer technique compatible with Consultive Committee for Space Data System (CCSDS) standards is studied and proposed. Special attention is given to synchronization accuracy, which is one of the most critical requirements for the navigation service. The choice of the technique has been supported by a trade-off analysis on the frequency reference to be adopted on board. Parameters such as Size, Weight and Power consumption (SWAP) have been taken into account in this phase, as well as costs and ground effort, paying particular attention to low-SWAP solutions. Finally, an error budget assessment is carried out considering free space propagation losses, relativistic effects, ephemeris errors, synchronization errors, and Earth's atmosphere contribution such as ionospheric and tropospheric delay

No COVID-19 pandemic impact on incidence and clinical presentation of celiac disease in Italian children

Aim: We aimed to evaluate the impact of Coronavirus Disease-19 (COVID-19) pandemic on the incidence and clinical presentation of celiac disease (CD) in children.MethodsThe diagnoses of CD were compared between the COVID-19 pandemic (from April 2020 to March 2022) and the pre-pandemic period (from April 2018 to March 2020) in three Italian Paediatric Gastroenterology centres (Varese, Como, Catanzaro). Electronic patient records were reviewed and additional information were collected through parental interview. The diagnosis of CD was made according to ESPGHAN criteria. SARS-CoV-2 infection was diagnosed based on pre-vaccination positive serum antibodies or nasopharyngeal swabs. Z test and chi-square were used for statistical analysis.ResultsThe overall number of paediatric diagnosis of CD did not differ between the two years pre-pandemic and pandemic periods (177 and 172 cases) in the three Italian participating centres. Clinical presentation of CD was also similar throughout the study periods. SARS-CoV-2 infection has been documented in 10.6% of children but only in 5.8% of these occurred before CD diagnosis.ConclusionDifferent to what reported for other autoimmune diseases, the incidence and presenting symptoms of CD in our paediatric population did not change during the COVID-19 pandemic compared to the previous 2 years

PTSD symptoms as a consequence of breast cancer diagnosis : clinical implications

It is a well-established multidisciplinary practice at the European Institute of Oncology, that nurses and physicians often report their difficulties to clinical psychologists regarding adherence to hospital scheduling and procedures, when faced with women who, having been diagnosed with cancer, may be too overwhelmed to understand medical advice. We thus undertook an observational-prospective-cohort study, to investigate the prevalence and variation of PTSD symptomatology in women awaiting a mastectomy at a mean of 30 days after diagnosis and up to 2 years after discharge from hospital. The presence of any correlations between PTSD symptoms and medical and psycho-social variables was also investigated. Between March 2011 and June 2012, 150 women entered the study and were evaluated at four points in time: pre-hospital admission, admission for surgery, hospital discharge and two years later. The prevalence of distress at pre-hospital admission was 20% for intrusion symptoms, 19.1% for avoidance symptoms and 70.7% for state anxiety. Intrusion was negatively correlated with time from diagnosis independently of tumor dimensions, i.e. independently of the perceived seriousness of the illness. Even though at two-year follow up the prevalence of intrusion and avoidance is similar to that in the general population, patients with high levels of intrusion and avoidance at pre-hospital admission will maintain these levels, showing difficulties in adjusting to illness even two years later. As for psycho-social factors, the presence of a positive cancer family and relational history is associated with high levels of distress, in particular with intrusive thinking. Proper interventions aimed at the management of these issues and at their implications in clinical practice is clearly warranted

International Telecommunication Union-Radiocommunication Sector P.837-6 and P.837-7 performance to estimate Indonesian rainfall

This work evaluated the performance of International Telecommunication Union-Radiocommunication Sector (ITU-R) P.837-6 and P.837-7 models (Annex 1) to estimate one-minute rainfall rates in Indonesia. In addition to the default ITU-R P.837-6, the input of ITU-R P.837-6 is also modified using data which has better spatial resolution, i.e. a combination of Tropical Rainfall Measuring Mission (TRMM) 3A25 and 3B43 (ITU-R+3A25+3B43), 3B42 and 3B43 (ITU-R+3B42+3B43), Global Satellite Mapping of Precipitation (ITU-R+GSMaP), and Global Precipitation Measurement (ITU-R+GPM). Among the five test sites, the default ITU-R P.837-6 and ITU-R+3A25+3B43 could predict one-minute rainfall rates at two locations accurately. The ITU-R P.837-7 exhibited a marginally better performance for sites that had a high percentage of very heavy rain, particularly at large (1%) and small (0.001%) percentages of time exceeded. The spatial distribution of rainfall rate produced by ITU-R P.837-7 and ITU-R+3A25+3B43 was closer to the pattern demonstrated by recent satellite precipitation measurements

The impact of space and time averaging on the spatial correlation of rainfall

Nowadays a huge amount of data is available for the statistical characterization of rainfall worldwide, although unfortunately not always with the adequate spatial and temporal resolution required for the very high demanding telecommunication applications. On the basis of the NIMROD radar network composite rain maps, first, this paper investigates separately the impact of space or time integration on the spatial correlation of rainfall r, a key parameter for most Propagation Impairment Mitigation Techniques (PIMTs), as well as for many prediction models such as time-space rain field generators. Analytical formulations are proposed to model the average trend of r with the distance d between two sites as a function of the integration time T or the integration area A, which, in turn, can be used to de-integrate the spatial correlation information estimated respectively from networks of raingauges with long integration time or from radar data with coarse spatial resolution. As an example, the last part of the paper compares the spatial rain decorrelation trends estimated by a database of radar maps collected in Northern Italy with the ones de-integrated from products of meteorological re-analyses (ERA40) or Earth Observation missions (TMPA 3B42)

Perioperative serum VEGF and extracellular domains of EGFR and HER2 in early breast cancer

Background: The prognostic role of serum levels of molecular biomarkers during the perioperative period in patients with early breast cancer is not clear. Patients and Methods: Serum VEGF and extracellular domains (ECD) of EGFR and HER2 were prospectively determined in 119 consecutive patients with early breast cancer on the day before and after surgery. Results: After a median follow-up of 93 months, the preoperative value and the absolute change from pre- to postoperative serum levels of VEGF and HER2 ECD did not predict disease-free survival (DFS). A decrease after surgery of EGFR ECD correlated with a statistically significant lower DFS; each 1 ng/ml decrease in EGFR ECD serum level was associated with an increase of event risk of 15% on multivariable analysis (hazard ratio 1.15 95% confidence interval 1.04.-1.28, p=0.006). Conclusion: The perioperative absolute change of EGFR ECD significantly correlated with disease outcome of patients with early breast cancer. No correlation was found between preoperative and perioperative absolute change of serum VEGF and HER2 ECD

Prevalence in bulk tank milk and epidemiology of Campylobacter jejuni in dairy herds in Northern Italy

Thermotolerant Campylobacter spp. are frequently the cause of human gastroenteritis and have assumed more importance in Italy following the increased consumption of raw milk. Our objectives were to determine the prevalence and genotypes of Campylobacter spp. in dairy herds and to investigate the possible sources of bulk milk contamination. Bulk milk from dairy herds (n = 282) was cultured for Campylobacter spp. and Enterobacteriaceae. At three Campylobacter jejuni-positive farms, bovine feces, pigeon intestines, milk, and water points were also investigated. Isolates were identified by PCR and genotyped using multilocus sequence typing (MLST). C. jejuni was detected in 34 (12%) bulk milk samples. The strains belonged to 14 sequence types, and the most common clonal complexes were CC-21, CC-48, and CC-403. No association was demonstrated between the presence of C. jejuni and high levels of Enterobacteriaceae in bulk milk. At the three farms examined, C. jejuni was isolated from bovine feces (25/82 [30.5%]), pigeon intestines (13/60 [21.7%]), bulk milk (10/24 [41.7%]), and water points (4/16 [25%]). MLST revealed lineages that were common between milk and bovine feces but distinct between cattle and pigeons. In one herd, C. jejuni with the same genotype was isolated repeatedly from bulk milk and a cow with an udder infection. Our results showed a high prevalence of C. jejuni in bulk milk and suggested that udder excretion, in addition to fecal matter, may be a route of bulk milk contamination. MLST analysis indicated that pigeons are probably not relevant for the transmission of C. jejuni to cattle and for milk contamination