Passive forward scatter radar based on satellite TV broadcast for air target detection: preliminary experimental results

The focus of this paper is on the detection of airborne targets and on the estimation of their velocity by means of passive forward scatter radar systems based on the DVB-S as transmitter of opportunity. Results related to an experimental campaign carried out near “Leonardo Da Vinci” airport (Rome, Italy) are shown. Particularly the Doppler signature spectrogram is analyzed for a single node FSR configuration and time delay techniques are analyzed for a multi-static configuration suitable for velocity estimation. Obtained results clearly show the feasibility of the DVB-S based FSR configuration to reliably detect aircrafts and the effectiveness of the proposed velocity estimation techniques even in the near field area

Yb3+-, Nd3+-, Ho3+-, and Tm3+- doped materials for optoelectronic applications

This thesis shows the growth process and spectroscopical characteristics of various luminescent materials for visible and infrared applications. Single crystals and thin films doped with rare earth elements (Nd, Yb, Tm and Ho) were grown and studied. The main aspects of their absorption and emission properties are shown and laser results are presented in a separate sections

Thermal noise and optomechanical features in the emission of a membrane-coupled compound cavity laser diode

We demonstrate the use of a compound optical cavity as linear displacement detector, by measuring the thermal motion of a silicon nitride suspended membrane acting as the external mirror of a near-infrared Littrow laser diode. Fluctuations in the laser optical power induced by the membrane vibrations are collected by a photodiode integrated within the laser, and then measured with a spectrum analyzer. The dynamics of the membrane driven by a piezoelectric actuator is investigated as a function of air pressure and actuator displacement in a homodyne configuration. The high Q-factor ($\sim 3.4\cdot 10^4$ at $8.3 \cdot 10^{-3}$ mbar) of the fundamental mechanical mode at $\sim 73$ kHz guarantees a detection sensitivity high enough for direct measurement of thermal motion at room temperature ($\sim 87$ pm RMS). The compound cavity system here introduced can be employed as a table-top, cost-effective linear displacement detector for cavity optomechanics. Furthermore, thanks to the strong optical nonlinearities of the laser compound cavity, these systems open new perspectives in the study of non-Markovian quantum properties at the mesoscale

Asymptomatic patients as a source of transmission of COVID-19 in homeless shelters

Objectives: Asymptomatic carriers account for over a third of all Coronavirus Disease 19 (COVID-19) cases and are characterized by the absence of symptoms but the same infectivity as symptomatic infections. The high percentage of asymptomatic COVID-19 patients is significant in settings with specific vulnerabilities, such as homeless shelters, where the consequences of an outbreak may be dramatic. In this work, we briefly report our experience on residents and staff of homeless shelters in the City of Rome, Italy, with a particular focus on asymptomatic transmission, and compare it with the available evidence. Methods: We performed routine Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) nasopharyngeal swab tests in all residents and staff of homeless shelters managed by the Eleemosynaria Apostolica of the Vatican City State in the city of Rome, Italy, in addition to daily symptom screening, body temperature monitoring, and application of other prevention measures. Results: We evaluated 298 persons and identified twelve positive cases (4%). Most of the positive cases (75%) were asymptomatic, while only three patients reported symptoms that included fever, diarrhea, and cough. Conclusions: Our data confirm the importance of early identification of asymptomatic carriers that could, in vulnerable conditions such as homeless shelters, spread the infection and cause outbreaks with severe consequences on individual and public health

Anaplasma phagocytophilum infection in thrombocytopenic dogs

Anaplasma and Ehrlichia spp. are tick-transmitted bacteria of clinical relevance in European dogs. The diagnosis of infection is often difficult due to the wide spectrum of disease caused by them. During infection, reduction in platelet count is considered the most common haematological abnormality, frequently representing the sole alteration in asymptomatic dogs. In this study, the presence of bacteria belonging to the genera Anaplasma and Ehrlichia was investigated in Northern Italy in blood samples from 159 thrombocytopenic dogs using a polymerase chain reaction (PCR) assay amplifying a portion of the heat shock gene (groEL). Obtained amplicons were sequenced and analysed. Two dogs were positive for A. phagocytophilum, while A. platys and E. canis were not detected. None of the PCR-positive dogs were diagnosed at the time of hospital admission, even in the presence of clinical signs and clinicopathological abnormalities potentially related to A. phagocytophilum infection. Nucleotide sequence analysis showed that the 2 detected strains belonged to the cluster Europe 1 and were different from each other. This study confirms the presence of A. phagocytophilum infections in dogs of Northern Italy, causing clinical signs and laboratory abnormalities that could not be properly diagnosed and treated