High resolution stopwatch for cents

A very low-cost, easy-to-make stopwatch is presented to support various experiments in mechanics. The high-resolution stopwatch is based on two photodetectors connected directly to the microphone input of the sound card. A dedicated free open-source software has been developed and made available to download. The efficiency is demonstrated by a free fall experiment

Using the Sound Card as a Timer

Experiments in mechanics can often be timed by the sounds they produce. In such cases, digital audio recordings provide a simple way of measuring time intervals with an accuracy comparable to that of photogate timers. We illustrate this with an experiment in the physics of sports: to measure the speed of a hard-kicked soccer ball.Comment: 3 pages, 4 figures, Late

The HOTSAT volcano monitoring system based on combined use of SEVIRI and MODIS multispectral data

Spaceborne remote sensing of high-temperature volcanic features offers an excellent opportunity to monitor the onset and development of new eruptive activity. To provide a basis for real-time response during eruptive events, we designed and developed the volcano monitoring system that we call HOTSAT. This multiplatform system can elaborate both Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and Infrared Imager (SEVIRI) data, and it is here applied to the monitoring of the Etna volcano. The main advantage of this approach is that the different features of both of these sensors can be used. It can be refreshed every 15 min due to the high frequency of the SEVIRI acquisition, and it can detect smaller and/or less intense thermal anomalies through the MODIS data. The system consists of data preprocessing, detection of volcano hotspots, and radiative power estimation. To locate thermal anomalies, a new contextual algorithm is introduced that takes advantage of both the spectral and spatial comparison methods. The derivation of the radiative power is carried out at all ‘hot’ pixels using the middle infrared radiance technique. The whole processing chain was tested during the 2008 Etna eruption. The results show the robustness of the system after it detected the lava fountain that occurred on May 10 through the SEVIRI data, and the very beginning of the eruption on May 13 through the MODIS data analysis

Cloud Photogrammetry from Space

The most commonly used method for satellite cloud top height (CTH) compares brightness temperature of the cloud with the atmospheric temperature profile. Because of the uncertainties of this method, we propose a photogrammetric approach. As clouds can move with high velocities, even instruments with multiple cameras are not appropriate for accurate CTH estimation. Here we present two solutions. The first is based on the parallax between data retrieved from geostationary (SEVIRI, HRV band; 1000 m spatial resolution) and polar orbiting satellites (MODIS, band 1; 250 m spatial resolution). The procedure works well if the data from both satellites are retrieved nearly simultaneously. However, MODIS does not retrieve the data at exactly the same time as SEVIRI. To compensate for advection in the atmosphere we use two sequential SEVIRI images (one before and one after the MODIS retrieval) and interpolate the cloud position from SEVIRI data to the time of MODIS retrieval. CTH is then estimated by intersection of corresponding lines-of-view from MODIS and interpolated SEVIRI data. The second method is based on NASA program Crew Earth observations from the International Space Station (ISS). The ISS has a lower orbit than most operational satellites, resulting in a shorter minimal time between two images, which is needed to produce a suitable parallax. In addition, images made by the ISS crew are taken by a full frame sensor and not a push broom scanner that most operational satellites use. Such data make it possible to observe also short time evolution of clouds

Determinants of enhanced thromboxane biosynthesis in renal transplantation

Background. Despite great improvement in patient and graft survival, the long-term morbidity and mortality in renal transplant recipients (RTRs) are still significant, with a high incidence of cardiovascular disease-related deaths. Methods. We investigated thromboxane (TXA2) biosynthesis and endothelial and coagulative activation in 65 patients who received a renal transplant. Results. The rate of TXA2 biosynthesis (urinary 11-dehydro-TXB2 excretion largely reflects platelet TXA2 production in vivo) was significantly (P < 0.0001) higher in RTRs than in healthy subjects. Plasma von Willebrand factor (vWF) and thrombin-antithrombin (TAT) complexes were significantly higher (P < 0.001) in RTRs compared with controls. Urinary 11-dehydro-TXB2 directly correlated with plasma vWF and cholesterol. We next examined the relative influence of cyclosporine A (CsA) on TXA2 biosynthesis and endothelial activation, comparing a group of RTRs not receiving CsA with an age- and sex-matched group of patients treated with CsA. Urinary excretion of 11-dehydro-TXB2 and plasma levels of vWF were significantly increased in RTRs who received CsA compared with those who did not. After an overall follow-up of 120 months, RTRs who experienced cardiovascular events had a higher frequency of abnormal plasma levels of vWF than patients who remained event free. Conclusion. Renal transplantation is associated with in vivo platelet activation highly related to endothelial activation. This is particularly evident in CsA-treated patients. Administration of drugs that are able to reduce or eliminate thromboxane-dependent platelet activation in vivo may be beneficial to reduce the risk of cardiovascular events in RTRs

LAV@HAZARD: A Web-Gis interface for volcanic hazard assessment

Satellite data, radiative power of hot spots as measured with remote sensing, historical records, on site geological surveys, digital elevation model data, and simulation results together provide a massive data source to investigate the behavior of active volcanoes like Mount Etna (Sicily,Italy) over recent times. The integration of these eterogeneous data into a coherent visualization framework is important for their practical exploitation. It is crucial to fill in the gap between experimental and numerical data, and the direct human perception of their meaning. Indeed, the people in charge of safety planning of an area need to be able to quickly assess hazards and other relevant issues even during critical situations. With this in mind, we developed LAV@HAZARD, a web-based geographic information system that provides an interface for the collection of all of the products coming from the LAVA project research activities. LAV@HAZARD is based on Google Maps application programming interface, a choice motivated by its ease of use and the user-friendly interactive environment it provides. In particular, the web structure consists of four modules for satellite applications (time-space evolution of hot spots, radiant flux and effusion rate), hazard map visualization, a database of ca. 30,000 lava-flow simulations, and real-time scenario forecasting by MAGFLOW on Compute Unified Device Architecture

The initial phases of the 2008-2009 Mt. Etna eruption: a multi-disciplinary approach for hazard assessment

Between 2007 and early 2008, the INGV monitoring networks on Etna volcano recorded a recharging phase that climaxed with a new effusive eruption on 13 May 2008, and lasted about 14 months. A dike-forming intrusion was accompanied by a violent seismic swarm, with more than 230 events recorded in the first six hours, the largest being ML = 3.9. In the meanwhile, marked ground deformation was recorded by the permanent tilt and GPS networks, and sudden changes in the summit area were detected by five continuously recording magnetic stations. Poor weather conditions did not allow direct observation of the eruptive events, but important information was provided by infrared satellite images that detected the start of lava fountains from the eruptive fissure, feeding a lava flow. This flow spread within the Valle del Bove depression, covering 6.4 km on the south-eastern flank of the volcano in a few hours. The seismicity and deformation pattern indicated that the dike-forming intrusion was propagating northwards. It produced a dry fracture field, which generated concern for the possibility that the eruptive fissures could expand downslope towards populated areas. Monitoring and modeling of the multi-disciplinary data, together with the simulations of ash dispersal and lava flows, allowed us both to infer the eruptive mechanisms and provide a correct interpretation of the ongoing phenomena, furnishing useful information for civil defense purposes. We describe how this approach of feedback between monitoring and research provides critical support to risk evaluation

Prognostic Value of Magnesium in COVID-19: Findings from the COMEPA Study

Magnesium (Mg) plays a key role in infections. However, its role in coronavirus disease 2019 (COVID-19) is still underexplored, particularly in long-term sequelae. The aim of the present study was to examine the prognostic value of serum Mg levels in older people affected by COVID-19. Patients were divided into those with serum Mg levels ≤1.96 vs. &gt;1.96 mg/dL, according to the Youden index. A total of 260 participants (mean age 65 years, 53.8% males) had valid Mg measurements. Serum Mg had a good accuracy in predicting in-hospital mortality (area under the curve = 0.83; 95% CI: 0.74–0.91). Low serum Mg at admission significantly predicted in-hospital death (HR = 1.29; 95% CI: 1.03–2.68) after adjusting for several confounders. A value of Mg ≤ 1.96 mg/dL was associated with a longer mean length of stay compared to those with a serum Mg &gt; 1.96 (15.2 vs. 12.7 days). Low serum Mg was associated with a higher incidence of long COVID symptomatology (OR = 2.14; 95% CI: 1.30–4.31), particularly post-traumatic stress disorder (OR = 2.00; 95% CI: 1.24–16.40). In conclusion, low serum Mg levels were significant predictors of mortality, length of stay, and onset of long COVID symptoms, indicating that measuring serum Mg in COVID-19 may be helpful in the prediction of complications related to the disease

A SO2 flux study of the Etna volcano 2020–2021 paroxysmal sequences

The persistent open-vent degassing of Mt. Etna is often punctuated by months-long paroxysmal sequences characterized by episodes of violent Strombolian to lava fountaining activity. Understanding these gas-fueled transitions from quiescence to eruption requires routine measurement of gas fluxes. Here, we report SO2 flux measurements, obtained from a permanent UV camera system, collected over a two-year-long period spanning two paroxysmal sequences of Etna’s New South East Crater (NSEC) in December 2020/April 2021 and May/October 2021. In both cases, SO2 flux increased from ≤ 3250&nbsp;Mg/day during “ordinary” activity to ≥ 4200&nbsp;Mg/day. We interpret these distinct SO2 degassing regimes in light of seismic and thermal observations and drawing on numerical simulations of sulfur degassing constrained by parental melt sulfur contents in Etna’s hawaiites. We find that initiation of a paroxysmal sequence results from an approximate doubling of the time-averaged rate of magma supply (and degassing) above the sulfur exsolution level (∼150&nbsp;MPa pressure), to &gt;4&nbsp;m3/s. This corroborates recent models that argue for the triggering of paroxysmal sequences by escalating supply of volatile-rich magma to a reservoir ∼3–4&nbsp;km below the summit region. The non-stationary nature of magma flow and volcanic degassing we identify highlights the need for sustained surveillance to characterize long-term atmospheric budgets of volcanic volatiles