Precision gravity measurements with atom interferometry

This experimental work is devoted to perform accurate gravity measurements using atom interferometry. In the last two decades, atom interferometry has developed from an interesting demonstration of quantum physics into an important tool for precision measurements in fundamental physics as well as for practical applications in geodesy and inertial navigation. Essentially all such high precision atom interferometers are nowadays implemented using laser cooled atoms interacting with specially tailored pulses of light acting as beam splitters and mirrors for the matter-waves. In particular, the thesis is focused on the measurement of the Newtonian gravitational constant G through the use of a Rb cold atomic fountain. It relies on the simultaneous measurement of the accelerations of two vertically displaced, freely falling cold atomic samples, by means of Raman atom interferometry. The use of two displaced sensors allow a dramatic common mode phase noise suppression, so highly accurate gradiometric measurements are possible. Well-characterized source masses are placed close to the interferometers in two different positions and the relative phase shift is recorded. This removes the effects of all the fixed masses and makes the measurement doubly differential, both in time and space. A faithful simulation of the gravitational field of the source masses provides a phase shift as a function of G. This is compared to the acquired differential phase shift and a value of the gravitational constant is extracted. A study of the systematics leads to an aimed relative accuracy of the order of 10^-4

The role of dalbavancin in the multi-disciplinary management of wound infections in orthopaedic surgery.

Antimicrobial resistance is continuously increasing among bacterial clinical isolates (especially methicillin resistance in Staphylococcus aureus, MRSA), negatively impacting on outcomes of patients with Surgical Site Infections (SSIs). A multi-disciplinary team work is essential for SSIs prevention and for the choice of antibiotic therapy of orthopaedic SSIs. In particular, an Antibiotic Stewardship (AS) approach is recommended for preserving the activity of old and new antimicrobials. Dalbavancin is a novel antimicrobial agent, belonging to the lipoglycopeptides family, recently approved by FDA for the treatment of ABSSSIs (Acute Bacterial Skin and Skin Structure Infections) and can be considered as a candidate for the treatment of orthopaedic superficial SSIs. An antimicrobial activity directed against MRSA and other multi-resistant Gram-positive pathogens, a bactericidal effect and an extremely extended half-life are among key features of this drug. Dalbavancin gives to clinicians the option to provid..

Comparison between local and regional anesthesia in arteriovenous fistula creation.

PURPOSE: Assessment of the effectiveness of Brachial Plexus Block (BPB) via axillary approach compared to regional anesthesia for arteriovenous fistula surgery in patients affected by end-stage renal disease. METHODS: We compared forty patients randomly divided into two groups. Group A underwent BPB procedure with 15 mL ropivacaine 1% and 10 mL of saline (0.9% NaCl) via axillary approach. Group B received local anesthesia with lidocaine 2%. The forearm blood vessels were assessed by Doppler ultrasonography before and after the intervention. RESULTS: BPB performed on Group A was associated with a considerable venous dilation and a significant decrease (48.7%, P<.05) in pulsatility index (PI) measured by Doppler ultrasound. In Group B, PI and venous dilation remained unaltered in the postoperative phase. No complications such as thrombosis or occlusion were encountered among patients who underwent BPB. CONCLUSIONS: The axillary-approached BPB was more advantageous than local anesthesia. Its effectiveness was because of venous dilation and the decrease in the PI, consequent to the reduction in peripheral resistances and the increase in local blood flow, thus offering an ideal background for fistula creation and short-term patency

The MOCAST+ Study on a Quantum Gradiometry Satellite Mission with Atomic Clocks

In the past twenty years, satellite gravimetry missions have successfully provided data for the determination of the Earth static gravity field (GOCE) and its temporal variations (GRACE and GRACE-FO). In particular, the possibility to study the evolution in time of Earth masses allows us to monitor global parameters underlying climate changes, water resources, flooding, melting of ice masses and the corresponding global sea level rise, all of which are of paramount importance, providing basic data on, e.g. geodynamics, earthquakes, hydrology or ice sheets changes. Recently, a large interest has developed in novel technologies and quantum sensing, which promise higher sensitivity, drift-free measurements, and higher absolute accuracy for both terrestrial surveys and space missions, giving direct access to more precise long-term measurements. Looking at a time frame beyond the present decade, in the MOCAST+ study (MOnitoring mass variations by Cold Atom Sensors and Time measures) a satellite mission based on an “enhanced” quantum payload is proposed, with cold atom interferometers acting as gravity gradiometers, and atomic clocks for optical frequency measurements, providing observations of differences of the gravitational potential. The main outcomes are the definition of the accuracy level to be expected from this payload and the accuracy level needed to detect and monitor phenomena identified in the Scientific Challenges of the ESA Living Planet Program, in particular Cryosphere, Ocean and Solid Earth. In this paper, the proposed payload, mission profile and preliminary platform design are presented, with end-to-end simulation results and assessment of the impact on geophysical applications

Optimisation Study of Co Deposition on Chars from MAP of Waste Tyres as Green Electrodes in ORR for Alkaline Fuel Cells

Oxygen Reduction Reaction (ORR) catalysts, from waste automobile tyres obtained from Microwave assisted pyrolysis (MAP), were enriched with Co and Cu using the simple treatments sonochemical and electrochemical deposition. Catalytic activity was evaluated through onset potential and number of exchanged electrons measurements. Electrochemical data demonstrate an improvement in catalytic activity of the electrochemical modified char with Co. Char electrodes enriched with Co show a maximum positive shift of 40 mV with respect to raw char electrodes with a number of exchanged electrons per O2 molecule close to 4 (as for Pt) for the best sample. This corresponds to a reduction of the production of unwanted oxygen peroxide from 23% for raw char to 1%. Sample structure evolution before and after electrochemical deposition and electro-catalysis was investigated by scanning transmission electron microscopy and XPS. Such electrochemical treatments open new possibilities of refining waste chars and finding an economic alternative to noble metals-based catalysts for alkaline fuel cells

Biodiversity of Indigenous Saccharomyces Populations from Old Wineries of South-Eastern Sicily (Italy): Preservation and Economic Potential

In recent years, the preservation of biodiversity has become an important issue. Despite much public discussion, however, current practices in the food industry seldom take account of its potential economic importance: on the contrary, the introduction of industrialized agriculture practices over large areas has often resulted in a dramatic reduction in biodiversity

Più competenze, meno disuguaglianze. Risultati di una sperimentazione di educazione linguistica inclusiva nella scuola secondaria di primo grado

Questo studio esamina i punteggi nelle prove Invalsi di classi che hanno partecipato o meno alla sperimentazione Osservare l'interlingua. Nella classe che ha partecipato alla sperimentazione, il livello complessivo è più alto che in tutte le classi di controllo, prese tanto individualmente che come gruppo. Ma ciò che risalta di più è che nella classe sperimentale gli alunni hanno profili più omogenei, in particolare per quanto riguarda il divario tra gli italiani e i nuovi italiani: sebbene questi ultimi abbiano in ogni caso un punteggio medio inferiore, la differenza è del 25% e non del 50% come nelle classi di controllo