Designing for Ballet Classes: Identifying and Mitigating Communication Challenges Between Dancers and Teachers

Dancer-teacher communication in a ballet class can be challenging: ballet is one of the most complex forms of movements, and learning happens through multi-faceted interactions with studio tools (mirror, barre, and floor) and the teacher. We conducted an interview-based qualitative study with seven ballet teachers and six dancers followed by an open-coded analysis to explore the communication challenges that arise while teaching and learning in the ballet studio. We identified key communication issues, including adapting to multi-level dancer expertise, transmitting and realigning development goals, providing personalized corrections and feedback, maintaining the state of flow, and communicating how to properly use tools in the environment. We discuss design implications for crafting technological interventions aimed at mitigating these communication challenges

Interacting Binaries with Eccentric Orbits. Secular Orbital Evolution Due To Conservative Mass Transfer

We investigate the secular evolution of the orbital semi-major axis and eccentricity due to mass transfer in eccentric binaries, assuming conservation of total system mass and orbital angular momentum. Assuming a delta function mass transfer rate centered at periastron, we find rates of secular change of the orbital semi-major axis and eccentricity which are linearly proportional to the magnitude of the mass transfer rate at periastron. The rates can be positive as well as negative, so that the semi-major axis and eccentricity can increase as well as decrease in time. Adopting a delta-function mass-transfer rate of 10^{-9} M_\sun {\rm yr}^{-1} at periastron yields orbital evolution timescales ranging from a few Myr to a Hubble time or more, depending on the binary mass ratio and orbital eccentricity. Comparison with orbital evolution timescales due to dissipative tides furthermore shows that tides cannot, in all cases, circularize the orbit rapidly enough to justify the often adopted assumption of instantaneous circularization at the onset of mass transfer. The formalism presented can be incorporated in binary evolution and population synthesis codes to create a self-consistent treatment of mass transfer in eccentric binaries.Comment: 16 pages, 8 figures, Accepted by The Astrophysical Journa

In situ stress database of the greater Ruhr region (Germany) derived from hydrofracturing tests and borehole logs

Between 1986 and 1995, 429 hydrofracturing tests have been carried out in six now-abandoned coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarises the results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13∘ in the westernmost located Friedrich Heinrich coal mine and 168 ± 23∘ in the easternmost located Westphalia coal mine. The mean SHmax orientation, based on 87 data records from this and already published studies, of 161 ± 43∘ is in good agreement with the regional stress orientation observed in northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result, although burdened by high uncertainties, shows that the discontinuities striking in the N–S and NW–SE directions have a higher slip tendency compared to the ones striking ENE–WSW and NNW–SSE, whereas a high dilation tendency is observed for discontinuities striking NNW–SSE and a low dilation tendency for the ones striking ENE–WSW. The stress orientation database is available under https://doi.org/10.24406/fordatis/200 (Kruszewski et al., 2022a), the stress magnitude database is available under https://doi.org/10.24406/fordatis/201 (Kruszewski et al., 2022b), whereas the hydrofracturing test reports are available under https://doi.org/10.24406/fordatis/222 (Kruszewski et al., 2022c).</p

PACS: 33.20.Fb, 33.20.Kf, 32.50.+d, 61.46.Df, 73.20.Mf, 78.67.Bf, 87

The enhancing properties of silver nanoparticles in surface-enhanced Raman scattering (SERS) and metalenhanced uorescence (MEF) are studied in this work. The obtained results conrm that the partial aggregation of nanoparticles leads to a great increase of Raman scattering cross-section but there are signicant dierences in SERS-activity of colloidal silver treated with various aggregating compounds. The dierences are interpreted through the analysis of both experimental and computational results. The same silver colloid covered with silica shell preventing the uorescence quenching makes possible a several-fold increase in uorescence emission. The eect strongly depends on thickness of the outer layer of nanoparticles. Geometrical parameters of nanoparticles (radius or radius and thickness of the adsorption layer in core-shell systems) are determined on the basis of the dynamic light scattering (DLS) data and extinction spectra analysis

Estimated Assessment of the Potential Impact of Driverassistance Systems Used in Automated Vehicles on the Level of Road Safety in Poland

Strengthening road safety in the face of the enormous development of the automotive in recent decades is crucial. The safety benefits of automated vehicles are paramount. Automated vehicles have the potential to remove human error in road traffic, which will help protect drivers and passengers, as well as pedestrians and bicyclists. The carried-out forecasts are pioneering for Polish road traffic conditions. In England, studies have been carried out to determine the estimated impact of autonomous vehicles on road safety in simulated traffic conditions on the motorway. In Poland, preliminary forecasts of the reduction in the number of road accidents were made; however, they were based on other assumptions. Therefore, estimating the impact of using autonomous vehicles in order to increase the level of road safety is an innovative activity for Polish road conditions. For the purposes of this article, available statistical data on vehicles registered in Poland, their equipment with advanced driver-assistance systems as well as accident data and their causes were analyzed. A diagnosis of Road Safety in Poland in 2018 (base year for further estimations) was made, taking into account the trend of recent years together with an indication of the most common causes of road accidents. These data were compiled with statistical data from other countries about the influence of driversupport systems on traffic safety. Possible potential for increasing Road Safety in Poland by the year 2030 was estimated. The analyses were prepared assuming different types of processes related to traffic, road safety, and the recent development of the passenger car fleet in Poland. Presented results show four scenarios of road safety change, where the number of accidents is reduced with statistical average of 5000 reduction in the year 2030. These expectations are based on various predictable factors connected with upgrade of car fleet quality and take into account changes in road safety observed in recent years. Based on the current trend of driving automation and rapid development of driver-support systems, the provided estimations were found reliable and likely. The conducted research shows the benefits and the need for the use of driver-assistance systems in vehicles as they can measurably affect the level of road safety

User Requirements for Autonomous Vehicles – a Comparative Analysis of Expert and Non-expert-based Approach

Given the rapid progress being made in the design and development of autonomous vehicles, society is reaching the situation whereby customers will be able to access a range of semi-autonomous vehicles. These vehicles have the capability to drive autonomously in certain circumstances, with minimal input from the driver, except situations when a Request to Intervene is issued. While user requirements differ across and between types of users, there is no unified set of user requirements which will be acceptable to all drivers. Motivated by the recent explosion of interest around autonomous mobility, the authors made an attempt to extract, rank and compare the requirements that should be met according to different types of users - experts and non-experts. An initial set of user requirements was obtained, recognizing that drivers will have different priorities and preferences in this most critical of handover scenarios

Equipotential Surfaces and Lagrangian points in Non-synchronous, Eccentric Binary and Planetary Systems

We investigate the existence and properties of equipotential surfaces and Lagrangian points in non-synchronous, eccentric binary star and planetary systems under the assumption of quasi-static equilibrium. We adopt a binary potential that accounts for non-synchronous rotation and eccentric orbits, and calculate the positions of the Lagrangian points as functions of the mass ratio, the degree of asynchronism, the orbital eccentricity, and the position of the stars or planets in their relative orbit. We find that the geometry of the equipotential surfaces may facilitate non-conservative mass transfer in non-synchronous, eccentric binary star and planetary systems, especially if the component stars or planets are rotating super-synchronously at the periastron of their relative orbit. We also calculate the volume-equivalent radius of the Roche lobe as a function of the four parameters mentioned above. Contrary to common practice, we find that replacing the radius of a circular orbit in the fitting formula of Eggleton (1983) with the instantaneous distance between the components of eccentric binary or planetary systems does not always lead to a good approximation to the volume-equivalent radius of the Roche-lobe. We therefore provide generalized analytic fitting formulae for the volume-equivalent Roche lobe radius appropriate for non-synchronous, eccentric binary star and planetary systems. These formulae are accurate to better than 1% throughout the relevant 2-dimensional parameter space that covers a dynamic range of 16 and 6 orders of magnitude in the two dimensions.Comment: 12 pages, 10 figures, 2 Tables, Accepted by the Astrophysical Journa

SMX and front-end board tester for CBM readout chain

The STS-MUCH-XYTER (SMX) chip is a front-end ASIC dedicated to the readout of Silicon Tracking System (STS) and Muon Chamber (MUCH) detectors in the Compressed Baryonic Matter (CBM) experiment. The production of the ASIC and the front-end boards based on it is just being started and requires thorough testing to assure quality. The paper describes the SMX tester based on a standard commercial Artix-7 FPGA module with an additional simple baseboard. In the standalone configuration, the tester is controlled via IPbus and enables full functional testing of connected SMX, front-end board (FEB), or a full detector module. The software written in Python may easily be integrated with higher-level testing software

The `666' collaboration on OGLE transits: I. Accurate radius of the planets OGLE-TR-10b and OGLE-TR-56b with VLT deconvolution photometry

Transiting planets are essential to study the structure and evolution of extra-solar planets. For that purpose, it is important to measure precisely the radius of these planets. Here we report new high-accuracy photometry of the transits of OGLE-TR-10 and OGLE-TR-56 with VLT/FORS1. One transit of each object was covered in Bessel V and R filters, and treated with the deconvolution-based photometry algorithm DECPHOT, to ensure accurate millimagnitude light curves. Together with earlier spectroscopic measurements, the data imply a radius of 1.22 +0.12-0.07 R_J for OGLE-TR-10b and 1.30 +- 0.05 R_J for OGLE-TR-56b. A re-analysis of the original OGLE photometry resolves an earlier discrepancy about the radius of OGLE-TR-10. The transit of OGLE-TR-56 is almost grazing, so that small systematics in the photometry can cause large changes in the derived radius. Our study confirms both planets as inflated hot Jupiters, with large radii comparable to that of HD 209458$b$ and at least two other recently discovered transiting gas giants.Comment: Fundamental updates compared to previous version; accepted for publication in Astronomy & Astrophysic