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

Night Eating Syndrome, circadian rhythms and seasonality. A study in a population of Italian university students

PURPOSE: The aim of this research was to assess the prevalence of Night Eating Syndrome (NES) in a university student population and to clear up the relationship between NES, depression and chronotype. The relation between NES and seasonality was also investigated. METHODS: The data were collected from a sample of 1136 students of the L'Aquila University, Italy. All subjects were invited to answer to the Sociodemographic Information Form and to take a self-report battery composed by four questionnaires: the Night Eating Questionnaire (NEQ), the Morningness Eveningness Questionnaire (MEQ), the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Beck Depression Inventory (BDI). RESULTS: The 5.3% of our population (60 subjects) reached the criteria for NES. The distribution of chronotypes in the sample was: Morning Type 15.3%, Intermediate 64.3% and Evening Type 20.4%. The 36.7% of the participants reaching the criteria for NES, obtained low scores on the MEQ. The data indicated that NEQ and MEQ scores are significantly inversely correlated (r=-.22; p<.01, two-tailed test). The 3.6% of our population (41 subjects) reached the criteria for Seasonal Affective Disorder (SAD) and 10.7% for subclinical SAD (121 subjects). Furthermore, the 11.7% of subjects with NES presented SAD and the 5% presented Subclinical SAD. The data demonstrated that NES and Global Seasonality Score (GSS) are significantly associated (r=.22; p<0.01, two-tailed test). CONCLUSIONS: The main finding of this study is the strong relation between NES and eveningness dimension. Our results help to clear up the literature debate about the role of eveningness dimension in the night eating, suggesting that subjects with NES present a circadian delay, not only in the food intake, but in the entire functioning. At the best of one knowledge this study is the first one to examine the relationship between NES and seasonality. This research found preliminary evidence that, similarly to the findings of previous studies in subjects with Bulimia Nervosa (BN) and Binge Eating Disorder (BED), night eating symptoms may vary significantly across the seasons; subjects with NES experience seasonal variation in their mood and in their eating patterns

Campionatore di profondità per gas disciolti

I sistemi di campionamento d’acque per lo studio dei gas disciolti, devono rispondere all’esigenza di mantenere integra la quantità di gas disciolto, in relazione al volume di acqua campionata, e di preservarne la composizione fino all’analisi in laboratorio. Le procedure di campionamento descritte in letteratura si riferiscono quasi esclusivamente a due tipologie di campionatori: a) bottiglie di campionamento tipo Niskin, progettate per il campionamento di acque profonde, ma che non consentono una facile operatività in laboratorio ed un’adeguata conservazione dei gas disciolti dopo il campionamento, soprattutto quando la loro pressione è superiore a quella atmosferica; b) bottiglie di vetro con tappi di gomma e ghiere di alluminio, estraendo i gas disciolti mediante l’immissione di un gas di estrazione, secondo la metodologia descritta in Capasso & Inguaggiato [1998] e Inguaggiato & Rizzo [2004]. In letteratura sono anche riportate metodologie di campionamento, per il prelievo delle acque in profondità, che utilizzano pompe peristaltiche; queste metodologie tuttavia provocano fenomeni di essoluzione e separazione dei gas disciolti, rendendo impossibile un’accurata stima delle quantità di gas disciolti per volume di acqua. Il campionamento di acque profonde, sia marine che lacustri, implica spesso la presenza di volatili disciolti aventi pressioni anche notevolmente superiori a quella atmosferica, con la facile conseguenza di indesiderati effetti di essoluzione precoce e perdita parziale dei gas stessi, poiché tali campioni si trovano a pressione più elevata rispetto a quella della superficie. Essendo, infatti, la concentrazione dei gas disciolti in acqua (Xi) legata alla pressione parziale del gas stesso (Pi), oltre che alla costante di Henry (Khi) (Xi=Pi/Khi), risulta evidente come una diminuzione della pressione rischi di fare raggiungere la sovrassaturazione delle specie gassose, la loro essoluzione e la loro parziale perdita. Quindi risulta di fondamentale importanza prelevare il campione d’acqua, coi gas disciolti, con campionatori in grado d’isolare il campione d’acqua prelevato dalle condizioni di pressione esterne, prevenendo la separazione del gas per depressurizzazione

The role of transforming growth factor-\u3b21 in airway inflammation of childhood asthma

TGF-beta-targeting structural and inflammatory cells has been implicated in the mechanisms leading to the inflammatory and restructuring processes in asthma, suggesting an impact of TGF-beta1 signaling on the development and persistency of this disease. We investigated the potential early involvement of TGF-beta1 activity in the immunological and molecular mechanisms underlying progression of inflammation in childhood asthma. We evaluated the levels of TGF-beta1 in induced sputum supernatants (ISSs) and the expression of small mother cell against decapentaplegic (Smad) 2 and Smad7 proteins in induced sputum cells (ISCs) from children with intermittent asthma (IA), moderate asthma (MA) and control subjects (C). Furthermore, we investigated the regulatory role of TGF-beta1 activity on eosinophil and neutrophil adhesion to epithelial cells using adhesion assay, and on the granulocyte expression of adhesion molecule CD11b/CD18 Macrophage-1 antigen (MAC-1), by flow cytometry. We found that the levels of TGF-beta1 are increased in ISSs of IA and MA in comparison to C, concomitantly to the activation of intracellular signaling TGFbeta/Smads pathway in ISCs. In MA, TGF-beta1 levels correlated with the number of sputum eosinophils and neutrophils. Furthermore, we showed the ability of sputum TGF-beta1 to promote eosinophil and neutrophil adhesion to epithelial cells, and to increase the expression of MAC-1 on the granulocyte surface. This study shows the activation of TGFbeta/Smad signaling pathway in the airways of children with IA and, despite the regular ICS treatment, in children with MA, and provides evidence for the contribution of TGF-beta1 in the regulation of granulocyte activation and trafficking

Measuring Composition & Growth of Ion Clusters of Sulfuric Acid, Ammonia, Amines & Oxidized Organics as First Steps of Nucleation in the CLOUD Experiment

The mechanisms behind the nucleation of vapors forming new particles in the atmosphere had been proven difficult to establish. One main aim of the CLOUD experiment was to explore in detail these first steps of atmospheric new particle formation by performing extremely well controlled laboratory experiments. We examined nucleation and growth in the presence of different mixtures of vapors, including sulfuric acid, ammonia, dimethylamine, and oxidation products of pinanediol or α-pinene. Among the employed state-of-the-art instrumentation, a high-resolution mass spectrometer that directly sampled negatively charged ions and clusters proved particularly useful. We were able to resolve most of the chemical compositions found for charged sub-2nm clusters and to observe their growth in time. These compositions reflected the mixture of condensable vapors in the chamber and the role of each individual vapor in forming sub-2nm clusters could be explored. By inter-comparing between individual experiments and ambient observations, we try to establish which vapors participate in nucleation in the actual atmosphere, and how

Leukotriene B4 production in human mononuclear phagocytes is modulated by interleukin-4-induced 15-lipoxygenase

The aim of this study was to evaluate the consequences of interleukin (IL)-4-induced 15-lipoxygenase (15-LO) expression on leukotriene B4 (LTB4) synthesis in human monocytes. Human monocytes incubated for 24, 48, and 72 h with IL-4 (10 ng/ml) were stimulated with Ca2+-ionophore A23187 (calcimycin; 5 \u3bcM) or opsonized zymosan. 15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE], LTB4, and arachidonic acid (AA) release were measured by high-performance liquid chromotography/radioimmunoassay, liquid chromotography/tandem mass spectrometry (LC/MS/MS), or gas chromatography/mass spectrometry. 15-LO activity was evaluated in AA-treated monocytes. 15-LO, 5-lipoxygenase (5-LO) and 5-LO activating protein (FLAP) expression were analyzed by reverse transcription-polymerase chain reaction. Neutrophil chemotactic activity was evaluated using a microtaxis chamber assay. A23187-induced synthesis of 15(S)-HETE was significantly increased after treatment with IL-4 (10 ng/ml) for 48 and 72 h (p < 0.001). Concomitant decrease of LTB4 release was observed after 72 h of incubation with IL-4 (p < 0.001). LC/MS/MS analysis confirmed the production of 15(S)-HETE and the significant inhibition of LTB4 synthesis in IL-4-treated monocyte after challenge with opsonized zymosan. IL-4 treatment induced 15-LO enzymatic activity as well as 15-LO mRNA, but did not affect either 5-LO or FLAP mRNA expression in monocytes. Supernatant from IL-4-treated monocytes showed significantly lower neutrophil chemotactic activity than controls. 15(S)-HETE significantly inhibited LTB4 production induced by A23187-stimulated human monocytes without affecting AA release. IL-4-induced expression of 15-LO in monocytes caused a significant reduction of LTB4 production. Whereas this effect did not reflect changes in 5-LO and FLAP mRNA expression, synthetic 15(S)-HETE was able to significantly inhibit the synthesis of LTB4, without affecting AA release

Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry

Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H2SO4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantitative detection of H2SO4 in the presence of dimethylamine by CIMS at atmospherically relevant concentrations. For the first time in the CLOUD experiment, the monomer sulfuric acid concentration was measured by a CIMS and by two CI-APi-TOF (Chemical Ionization-Atmospheric Pressure interface-Time Of Flight) mass spectrometers. In addition, neutral sulfuric acid clusters were measured with the CI-APi-TOFs. The CLOUD7 measurements show that in the presence of dimethylamine (Peer reviewe