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

Argon plasma coagulation in the treatment of post-radiotherapy rectal bleeding

Introduction: Chronic radiation proctitis is often associated to radiotherapy for treatment of pelvic cancer. The most common side effect of this pathological condition is rectal bleeding but despite the great number of clinical approaches and techniques that have been employed no consensus for the management of it is available. Although prospective randomized trials about hemorrhagic radiation proctitis are still lacking, endoscopic approach delivering an Argon Plasma Coagulation (APC) seems to be a successful and available option. Patients and Methods: Sixteen patients suffering from post-radiotherapy rectal bleeding were followed. In the nine cases presenting a rectum ulcerative colitis (RUC) like endoscopic picture a 5-ASA therapeutic approach was chosen initially, followed by an APC treatment of areas of telangectasias. The other cases, presenting only areas of telangectasias, were treated only with APC. Results: 5-ASA therapy led to an improvement of inflammation state related to RUC but recurrence of rectal bleeding caused by telangectasias was observed. In these cases an additional APC treatment gave a total remission of the problem. Also in the other cases, presenting only areas of telangectasias, a remission of rectal bleeding was achieved through APC application. Conclusions: In the cases of radiation proctitis characterized by a severe compromission of rectal mucosa integrity an anti-inflammatory pharmacological therapy is necessary but not sufficient to abrogate rectal bleeding which is often caused by the presence of areas of telangectasias. In these cases a remission of the problem could be achieved through a combination of anti-inflammatory therapy (5-ASA) and APC

A New Algorithm for the Global-Scale Quantification of Volcanic SO2 Exploiting the Sentinel-5P TROPOMI and Google Earth Engine

Sulfur dioxide (SO2) is sourced by degassing magma in the shallow crust; hence its monitoring provides information on the rates of magma ascent in the feeding conduit and the style and intensity of eruption, ultimately contributing to volcano monitoring and hazard assessment. Here, we present a new algorithm to extract SO2 data from the TROPOMI imaging spectrometer aboard the Sentinel-5 Precursor satellite, which delivers atmospheric column measurements of sulfur dioxide and other gases with an unprecedented spatial resolution and daily revisit time. Specifically, we automatically extract the volcanic clouds by introducing a two-step approach. Firstly, we used the Simple Non-Iterative Clustering segmentation method, which is an object-based image analysis approach; secondly, the K-means unsupervised machine learning technique is applied to the segmented images, allowing a further and better clustering to distinguish the SO2. We implemented this algorithm in the open-source Google Earth Engine computing platform, which provides TROPOMI imagery collection adjusted in terms of quality parameters. As case studies, we chose three volcanoes: Mount Etna (Italy), Taal (Philippines) and Sangay (Ecuador); we calculated sulfur dioxide mass values from 2018 to date, focusing on a few paroxysmal events. Our results are compared with data available in the literature and with Level 2 TROPOMI imagery, where a mask is provided to identify SO2, finding an optimal agreement. This work paves the way to the release of SO2 flux time series with reduced delay and improved calculation time, hence contributing to a rapid response to volcanic unrest/eruption at volcanoes worldwide

Legacy PBDEs and NBFRs in sediments of the tidal River Thames using liquid chromatography coupled to a high resolution accurate mass Orbitrap mass spectrometer

Surface sediment samples (n = 45) were collected along a 110 km transect of the river Thames in October 2011, starting from Teddington Lock out through the industrial area of London to the southern North Sea. Several legacy and novel brominated flame retardants (NBFRs) were analysed, including 13 polybrominated diphenyl ethers (PBDEs) (congeners 17, 28, 47, 99, 100, 153, 154, 183, 196, 197, 206, 207 and 209), hexabromocyclododecane (HBCDDs), tetrabromobisphenol A (TBBPA), hexabromobenzene (HBB), 2,4,6-tribromophenol (TBP), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB or TBB), bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP or TBPH), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), pentabromoethylbenzene (PBEB), anti/syn-dechlorane plus (a/s-DP), 2,2',4,4',5,5'-hexabromobiphenyl (BB153) and α-,β-1,2-dibromo-4-(1,2-dibromoethyl) cyclohexane (α-,β-DBE-DBCH or TBECH). A novel analysis method based on liquid chromatographic separation, followed by high resolution accurate mass detection using the Orbitrap platform was used for quantification. Results revealed that BDE-209 had the highest concentrations (&lt;0.1 to 540 μg kg-1 dw) and detection frequency, accounting for 95% of all PBDE congeners measured. Indicative evidence of debromination of the PentaBDE technical mixture was observed through elevated relative abundance of BDE-28 in sediment compared to the Penta-BDE formulation. NBFRs were detected at comparable levels to PBDEs (excluding BDE-209), which indicates increasing use of the former. Spatial trend analysis showed that samples from industrial areas had significantly higher concentrations of Σ12PBDEs, ΣHBCDDs, TBBPA, BEH-TEBP, BTBPE and TBP. Three locations showed high concentrations of HBCDDs with diastereomer patterns comparable to the technical mixture, which indicate recent input sources to the sediment.</p

A Case of Syphilis With Ocular Involvement: Persistent Negative Serology in a Patient With Multiple Sclerosis

: Diagnostic algorithms for syphilis are based on serology. However, with the advent of immunosuppressive therapies, these algorithms may fail. We report a case of an individual with multiple sclerosis on treatment with ofatumumab and secondary syphilis with visual and auditory systems involvement and persistent negative treponemal and nontreponemal tests