Device for measuring heart rate parameters and generating radio-physical feedback signals.

The prototype of the device for radio-physical diagnostics of heart rate has been developed. The modular structure of the device is described. An intelligent sensor is selected for data acquisition and measurement system. Data exchange procedure between sensor and computer is configured on hardware and software level. Digital signal processing algorithms, in particular, filtering, cancelling artifacts of various nature and spectral analysis of biophysical data have been implemented. The results of measuring the heart rate variability are demonstrated. The concept of selecting a signal for organism exposure is represented, which uses information about heart rate fluctuations.

Polarimetry and spectroscopy of the “oxygen flaring” DQ Herculis-like nova: V5668 Sagittarii (2015)

Context. Classical novae are eruptions on the surface of a white dwarf in a binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell of gas and dust around the system. The three-dimensional structure of these shells is difficult to untangle when viewed on the plane of the sky. In this work a geometrical model is developed to explain new observations of the 2015 nova V5668 Sagittarii. Aim. We aim to better understand the early evolution of classical nova shells in the context of the relationship between polarisation, photometry, and spectroscopy in the optical regime. To understand the ionisation structure in terms of the nova shell morphology and estimate the emission distribution directly following the light curve’s dust-dip. Methods. High-cadence optical polarimetry and spectroscopy observations of a nova are presented. The ejecta is modelled in terms of morpho-kinematics and photoionisation structure. Results. Initially observational results are presented, including broadband polarimetry and spectroscopy of V5668 Sgr nova during eruption. Variability over these observations provides clues towards the evolving structure of the nova shell. The position angle of the shell is derived from polarimetry, which is attributed to scattering from small dust grains. Shocks in the nova outflow are suggested in the photometry and the effect of these on the nova shell are illustrated with various physical diagnostics. Changes in density and temperature as the super soft source phase of the nova began are discussed. Gas densities are found to be of the order of 109 cm−3 for the nova in its auroral phase. The blackbody temperature of the central stellar system is estimated to be around 2.2 × 105 K at times coincident with the super soft source turn-on. It was found that the blend around 4640 Å commonly called “nitrogen flaring” is more naturally explained as flaring of the O II multiplet (V1) from 4638–4696 Å, i.e. “oxygen flaring”. Conclusions. V5668 Sgr (2015) was a remarkable nova of the DQ Her class. Changes in absolute polarimetric and spectroscopic multi-epoch observations lead to interpretations of physical characteristics of the nova’s evolving outflow. The high densities that were found early-on combined with knowledge of the system’s behaviour at other wavelengths and polarimetric measurements strongly suggest that the visual “cusps” are due to radiative shocks between fast and slow ejecta that destroy and create dust seed nuclei cyclically.

CycloTRACK (v1.0) – tracking winter extratropical cyclones based on relative vorticity: sensitivity to data filtering and other relevant parameters

In this study we present a new cyclone identification and tracking algorithm, cycloTRACK. The algorithm describes an iterative process. At each time step it identifies all potential cyclone centers, defined as relative vorticity maxima embedded in smoothed enclosed contours of at least 3 × 10−5 s−1 at the atmospheric level of 850 hPa. Next, the algorithm finds all the potential cyclone paths by linking the cyclone centers at consecutive time steps and selects the most probable track based on the minimization of a cost function. The cost function is based on the average differences of relative vorticity between consecutive track points, weighted by their distance. Last, for each cyclone, the algorithm identifies "an effective area" for which different physical diagnostics are measured, such as the minimum sea level pressure and the maximum wind speed. The algorithm was applied to the ERA-Interim reanalyses for tracking the Northern Hemisphere extratropical cyclones of winters from 1989 until 2009, and we assessed its sensitivity for the several free parameters used to perform the tracking.

Tracking winter extra-tropical cyclones based on their relative vorticity evolution and sensitivity to prior data filtering (cycloTRACK v1.0)

In this study we present a new cyclone identification and tracking algorithm. Identification is based on a recognition pattern of enclosed contours of 850 hPa filtered relative vorticity values, while tracking is based on the minimization of a cost function. In particular, for each tracked cyclone our algorithm builds all possible tracks and finally chooses the one which presents the least differences of relative vorticity between consecutive track points. In parallel, for each track point the algorithm provides a cyclone area within which different physical diagnostics are calculated (such as pressure and wind speed). The area size is a function of the cyclone relative vorticity. To validate our approach we apply the algorithm on the Northern Hemisphere for the winters of 1989–2009. Three integrations of the algorithm were performed, each by using different filtering strengths. Using the three integrations, we assess the algorithm sensitivity to prior filtering the relative vorticity field. We show that filtering the input relative vorticity fields has an impact only on the weak cyclones, while in their majority the strong cyclones are independently detected and tracked.