282 research outputs found
EPIGRAFIA ROMANA IN SARDEGNA. Atti del I Convegno di studio Sant'Antioco, 14-15 luglio 2007 (=Incontri insulari, 1)
No full textInGaAs/InP SPAD with Monolithically Integrated Zinc-Diffused Resistor
No full textAfterpulsing and optical crosstalk are significant performance limitations for applications employing near-infrared single-photon avalanche diodes (SPADs). In this paper, we describe an InGaAs/InP SPAD with monolithically integrated resistor that is fully compatible with the planar fabrication process and provides a significant reduction of the avalanche charge and, thus, of afterpulsing and optical crosstalk. In order to have a fast SPAD reset (<50 ns), we fabricated quenching resistors ranging from 10 to 200 k\Ω, smaller than what is available in the literature. The resistor, fabricated with the zinc diffusions already used for avoiding premature edge-breakdown, promptly reduces the avalanche current to a low value ∼ 100~ μ A in less than 1 ns, while an active circuit completes the quenching and enforces a well-defined hold-off. The proposed mixed-quenching approach guarantees an avalanche charge reduction of more than 20 times compared with similar plain SPADs, enough to reduce the hold-off time down to 1 μ s. Finally, a compact single-photon counting module based on this detector and featuring 70-ps photon-timing jitter is presented
Model to simulate medium-voltage active networks with an aggregated view of the low-voltage ends
No full textThe integration of renewable energy sources into distribution networks requires a significant change in the traditional planning and operational approach. In medium-voltage (MV) networks, in order to guarantee reliable and secure electricity supply, fostering the connection of new generation, some smart techniques, are based on the integration of operation practices in the set of possible planning alternatives, are being studied. In low-voltage (LV) networks, where distributed generation (DG), mainly photovoltaic producers, are connected in proximity to existing consumers, similar smart control techniques are being considered, either on the producer side (for instance reactive power control) or on the load side (active demand management). One of the main problems associated to the massive connection of DG is represented by the voltage quality. This study aims to describe and apply a model to simulate MV networks, while studying the maximum voltage variations in the underlying LV networks
Author Response
No full textReply to the letter to the Editor “Complete transparency of a systematic review for readers”.
First of all, we thank for the contribution aimed to improve a complete transparency of our systematic review for readers. It allows us to clarify some aspects that we did not specify in the published manuscript.
We agree with you on the importance of the PRISMA statement that guided our systematic review, because the first author of its original paper, Prof. Liberati Alessandro, who disappeared prematurely, was our mentor. This can be an opportunity to remember him and his great commitment to the scientific community. Therefore, we confirm that we followed the PRISMA statement suggestions concerning the methods used for the systematic review. More specifically, despite we did not register the study protocol, we did not amend in any case our research design after the initiation of our study.
A protocol exists but it was not made public and it is a “data not shown”. In the protocol we established a priori the objectives and methods of our review, the outcomes, the methods of data extraction and those for qualitative and quantitative synthesis. The protocol was not modified during the editing of the systematic review.
Moreover, we extracted data in an agreed beforehand report, an excel cartel with color codes. We verified the report on some randomly selected studies and then it was improved accordingly. Subsequently two authors extracted all the data independently. The disagreements were solved by discussion among all the authors and if consent was not reached the decision was made by the most expert author. It was not necessary contacting other authors for more information.
We searched data about the characteristics of participants (e.g. age, diagnosis, symptoms, red flags, inclusion and exclusion criteria), the characteristics of interventions (e.g. type, dosage, position, and time of traction, and type of physical therapy interventions), the characteristics of outcome measures for pain and disability.
The data we extracted from included studies were about authors (names of Authors, countries, and publication years), characteristics of participants (number of participants for each group, mean age, and gender), outcome measures employed for pain and disability (e.g. VAS, NRS, Neck Pain and Disability Scale, etc.), follow-up timing (e.g. immediately post-treatment and/or at different post-treatment intervals), results (means and standard deviations at pre- and post-treatment for each outcome measure and for each follow-up time), and adverse events.
We hope that these clarifications will improve the readability of the systematic review on the effectiveness of traction added to physical therapy interventions in cervical radiculopathy
Remifentanil in critically ill cardiac patients
No full textRemifentanil has a unique pharmacokinetic profile, with a rapid onset and offset of action and a plasmatic metabolism. Its use can be recommended even in patients with renal impairment, hepatic dysfunction or poor cardiovascular function. A potential protective cardiac preconditioning effect has been suggested. Drug-related adverse effects seem to be comparable with other opioids. In cardiac surgery, many randomized controlled trials demonstrated that the potential benefits of the use of remifentanil not only include a profound protection against intraoperative stressful stimuli, but also rapid postoperative recovery, early weaning from mechanical ventilation, and extubation. Remifentanil shows ideal properties of sedative agents being often employed for minimally invasive cardiologic techniques, such as transcatheter aortic valve implantation and radio frequency treatment of atrial flutter, or diagnostic procedures such as transesophageal echocardiography. In intensive care units remifentanil is associated with a reduction in the time to tracheal extubation after cessation of the continuous infusion; other advantages could be more evident in patients with organ dysfunction. Effective and safe analgesia can be provided in case of short and painful procedures (i.e. chest drain removal). In conclusion, thanks to its peculiar properties, remifentanil will probably play a major role in critically ill cardiac patients
Low Dark Count Rate and Low Timing Jitter InGaAs/InP Single-Photon Avalanche Diode
No full textWe describe the design and characterization of a new InGaAs/InP Single-Photon Avalanche Diode (SPAD) for single-photon detection at 1.55 μm with high detection efficiency, low noise and low timing jitter. The design and fabrication have been optimized to reduce the defects (responsible for dark counts and afterpulsing). Zinc diffusion is a key step and we optimized the profile, pattern and reactor parameters to achieve uniform sensitivity in the active area, low noise and low timing jitter. The active area diameter of the device here described is 25 μm and no floating guard rings are present. It is operated in gated mode, with passive quenching, for the characterization. The dark count rate is in the order of few kilo-counts per second at 225 K and 5 V of excess bias. The photon timing resolution, measured as the full-width at half maximum of the response to a 20 ps pulsed laser, is about 90 ps, with a clean exponential tail whose time constant is about 60 ps. The photon detection efficiency is about 30% at 1550 nm. These specifications make our InGaAs/InP SPAD a good candidate for advanced time-correlated single-photon counting applications at wavelengths up to 1700 nm
Time-gated single-photon detection module with 110 ps transition time and up to 80 MHz repetition rate
No full textWe present the design and characterization of a complete single-photon counting module capable of time-gating a silicon single-photon avalanche diode with ON and OFF transition times down to 110 ps, at repetition rates up to 80 MHz. Thanks to this sharp temporal filtering of incoming photons, it is possible to reject undesired strong light pulses preceding (or following) the signal of interest, allowing to increase the dynamic range of optical acquisitions up to 7 decades. A complete experimental characterization of the module highlights its very flat temporal response, with a time resolution of the order of 30 ps. The instrument is fully user-configurable via a PC interface and can be easily integrated in any optical setup, thanks to its small and compact form factor
Wagner Syndrome-like fundus presentation of atypical Persistent Fetal Vasculature
No full textPurpose To report the case of a woman with atypical Persistent fetal vasculature (PFV) accompanied by more typical findings of Wagner Syndrome.Results A 58-year-old woman complained about persistent flashes and floaters for more than 6 months. Multimodal retinal imaging showed Bergmeister papilla and a fibrous gray strand floating behind the macula in the right eye. Ultra-wide field retinography revealed a 270 degrees paving-stone degeneration and a nasal circumferential vitreous veil in both eyes. Functional and genetic testing were negative for inherited retinal diseases.Conclusions and importance PFV spectrum confirms its heterogeneous presentation. We report an atypical adult PFV case in presence of retrolental and optic nerve head stalks, accompanied by extensive peripheral vitreoretinal degenerations. This case may expand the current understanding of PFV presentation in adulthood
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