Catalog of 2017 Thunderstorm Ground Enhancement (TGE) events observed on Aragats

The natural electron accelerator in the clouds above Aragats high-altitude research station in Armenia operates continuously in 2017 providing more than 100 Thunderstorm Ground enhancements (TGEs). Most important discovery based on analysis of 2017 data is observation and detailed description of the long-lasting TGEs. We present TGE catalog for 2 broad classes according to presence or absence of the high-energy particles. In the catalog was summarized several key parameters of the TGEs and related meteorological and atmospheric discharge observations. The statistical analysis of the data collected in tables reveals the months when TGEs are more frequent, the daytime when TGEs mostly occurred, the mean distance to lightning flash that terminates TGE and many other interesting relations. Separately was discussed the sharp count rate decline and following removal of high-energy particles from the TGE flux after a lightning flash. ADEI multivariate visualization and statistical analysis platform make analytical work on sophisticated problems rather easy; one can try and test many hypotheses very fast and come to a definite conclusion allowing crosscheck and validation

Cleaning and sputtering using planar acoustoplasma magnetron

The paper describes the obtained experimental results for a planar acoustoplasma magnetron. The small radius of the anode loopallows focusing and accelerating the ionic component of the sprayed material.Argon was used as a buffer gas. The characteristics of the magnetron in case of direct current supply and in acoustoplasma mode(AP) (with modulated current containing constant and variable components) are compared. The sputtering speed in AP modeincreases. For the copper cathode, the gas pressure made < 1 Pa and current density of the order of 100 mA/cm2with increasingdistance from the anode to the deposited substrate from 2 to 4 cm in case of DC supply, the deposition speed drops 3.3 times (from17 to 5 nm/s), in the acoustoplasma mode – 2 times (from 13 to 6.4 nm/s).For the anode-substrate distance 4 cm, the gain in the deposition speed in the AP mode, compared with DC is 1.2–1.5 times. Thedependences of ion and electron currents on the substrate for different discharge parameters were measured. The study was basedon a scheme with two potential grids with fixed and variable potentials. The possibility of forming an annular vapor-plasma flowof fast particles is shown

Left atrial strain as a predictor of atrial fibrillation in patients with asymptomatic severe aortic stenosis and preserved left ventricular systolic function

Aim. To study the structural and functional left heart parameters in patients with severe aortic stenosis (AS) and preserved ejection fraction (EF) in order to determine the risk of atrial fibrillation (AF).Material and methods. The study included 84 patients (men, 37; mean age, 68±8 years) with severe AS and EF &gt;55%. All patients had sinus rhythm and were asymptomatic. Echocardiography was performed to assess longitudinal strain of the left ventricle (LVLS), right ventricle, left atrium (LALS) and the left atrial stiffness (LAS) using the speckle tracking method. Left ventricular mass index (LVMI) and maximum left atrium volume index (LAVI) were also determined. Patients were followed up for 1 year.Results. AF was reported in 27 (32%) patients, of which 9 (33%) had asymptomatic AF episodes detected by 48-hour electrocardiography. Eighteen (67%) patients with AF felt palpitations. Patients with and without episodes of atrial fibrillation had non-significant differences in LVMI, LAVI, and LVLS. Patients with atrial fibrillation had a lower LALS and a higher LAS compared with patients without atrial fibrillation. Regression analysis revealed that LALS and LAS were independent predictors of AF.Conclusion. AF develops in about one third of asymptomatic patients with severe AS and normal EF. The development of AF predisposes to the onset of AS symptoms in most patients. LALS and LAS were predictors of AF in these patients. Identification of patients at risk of AF will allow for earlier aortic valve replacement

Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN.

We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57&nbsp;keV gives an effective neutrino mass square value of (-1.0_{-1.1}^{+0.9})  eV^{2}. From this, we derive an upper limit of 1.1&nbsp;eV (90%&nbsp;confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a factor of 2 and provides model-independent input to cosmological studies of structure formation

Commissioning of the vacuum system of the KATRIN Main Spectrometer

The KATRIN experiment will probe the neutrino mass by measuring the beta-electron energy spectrum near the endpoint of tritium beta-decay. An integral energy analysis will be performed by an electro-static spectrometer (Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m^3, and a complex inner electrode system with about 120000 individual parts. The strong magnetic field that guides the beta-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300{\deg}C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10^{-11} mbar range. It is demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016.Comment: submitted for publication in JINST, 39 pages, 15 figure