Context.
Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. ...This was an important limiting factor as the most fragile – hence precious – meteorites must be recovered rapidly to avoid their alteration.
Aims.
The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receivers and covers an area of about 1.5 × 10
6
km
2
.
Methods.
The FRIPON network, fully operational since 2018, has been monitoring meteoroid entries since 2016, thereby allowing the characterization of their dynamical and physical properties. In addition, the level of automation of the network makes it possible to trigger a meteorite recovery campaign only a few hours after it reaches the surface of the Earth. Recovery campaigns are only organized for meteorites with final masses estimated of at least 500 g, which is about one event per year in France. No recovery campaign is organized in the case of smaller final masses on the order of 50 to 100 g, which happens about three times a year; instead, the information is delivered to the local media so that it can reach the inhabitants living in the vicinity of the fall.
Results.
Nearly 4000 meteoroids have been detected so far and characterized by FRIPON. The distribution of their orbits appears to be bimodal, with a cometary population and a main belt population. Sporadic meteors amount to about 55% of all meteors. A first estimate of the absolute meteoroid flux (mag < –5; meteoroid size ≥~1 cm) amounts to 1250/yr/10
6
km
2
. This value is compatible with previous estimates. Finally, the first meteorite was recovered in Italy (Cavezzo, January 2020) thanks to the PRISMA network, a component of the FRIPON science project.
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Low-voltage current interruption is studied in this paper in order to develop a suitable blackbox model for low-voltage circuit breakers. The electric arc will be modeled by means of electrical ...quantities. Accurate post-arc current measurements by a high sensitivity current probe and signal analysis techniques (Savitsky-Golay filtering) are adopted to extract information. A set of interrupting performance evaluators is proposed, and the best performing indicators are selected. Theoretical explanations provide insight in the physical processes of low-voltage interruption. The difference with the classical context of blackbox modeling in medium- and high-voltage circuit breakers is explained, based on the different relative weight of the arc voltage and voltage supply.
The authors describe their experience about long-term VAD (Venous Access Devices) placement and in particular of placement techniques types of catheters, complications, and risk and benefit. 243 ...placements of VAD in 112 males and 131 females mainly affected by leukemia or breast cancer have been analyzed. 145 Leonard, 54 Groshong and 44 Hickman type silicon catheters have been implanted. The preferred access vein was the right internal jugular vein in 75% of patients and the right subclavian vein in the remained. The results show implant success in 98.7% of the patients. Complications have been rare and not serious and they have been divided into: 1) complications due to venipuncture, 2) complications during implant, 3) complications during the staying of catheter, 4) complications during the removal. The authors underline the advantages of puncture access through the right internal jugular vein in comparison with access through the right subclavian vein. Groshong type catheter is better than Leonard and Hickman. Very few infections have been noticed and patients seem to accept more willingly percutaneous placement than surgical one.
Little information is available about the extent and the time course of possible impairment of cerebral circulation occurring after aneurysmal subarachnoid haemorrhage (SAH). The aim of this study ...was to correlate cerebral autoregulation, neurological impairment at surgery and timing of surgery in patients with ruptured intracerebral aneurysms.
Cortical blood flow (CoBF) was measured intraoperatively by a thermal diffusion probe in 77 patients during surgery for ruptured supratentorial aneurysms, who were operated on at different time intervals after bleeding. An autoregulation index (AI), expressed as the ratio between the change in CoBF and the change of mean arterial blood pressure at the time of rising the systemic blood pressure after occlusion of the aneurysm(s), was determined in each case.
Among good-grade patients (WFNS grade I-II), those operated on days 0-2 after SAH had a significantly better autoregulatory response, compared either with patients who underwent surgery on days 3-7 after bleeding (p<0.01), or with those whose aneurysm was occluded more than 7 days after rupture (p<0.03). The mean AI of poor-grade patients (WFNS grade IV-V), who received surgery on days 0-2 after SAH, was significantly higher (p<0.01) compared with the corresponding value of good-grade patients. No significant difference was found between the mean AIs of patients who subsequently did, or did not, develop symptomatic vasospasm.
It is concluded that good-grade patients operated on within 48 hours after bleeding take advantage of a preserved autoregulatory function during controlled hypotension.
Intracranial haemorrhage from ruptured aneurysm or bleeding in arteriovenous malformation is rare, but may result in significant maternal and fetal mortality and serious neurological morbidity in ...survivors. Surgical intervention creates risks for the mother and her fetus, but is the best form of management. The anaesthetic procedure can present many clinical dilemmas, one of which is the role of induced hypotension. This review will focus on the diagnosis and management of this dramatic event.
The CBF of eight patients, who underwent surgery for ruptured aneurysm, was monitored using the termodiffusion technique (TDF). The device employed in this investigation allowed a continuous ...monitoring in "real time" of the cortical flow. The purpose of the study was to detect disorders of autoregulation, which were evaluated with the autoregulation index (AI). Autoregulation was correlated with the neurological preoperative grading, the postoperative changes of CBF (Xe133 clearance) and the outcome. The results of this preliminary study showed a correlation between these parameters and stressed the value of CBF monitoring during surgery.
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