Vibrational Instability due to Coherent Tunneling of Electrons

Effects of a coupling between the mechanical vibrations of a quantum dot placed between the two leads of a single electron transistor and coherent tunneling of electrons through a single level in the dot has been studied. We have found that for bias voltages exceeding a certain critical value a dynamical instability occurs and mechanical vibrations of the dot develop into a stable limit cycle. The current-voltage characteristics for such a transistor were calculated and they seem to be in a reasonably good agreement with recent experimental results for the single $C_{60}$-molecule transistor by Park et al.(Nature {\bf 407,} (2000) 57).Comment: 5 pages, 3 figure

Gender quotas in the boardroom: New evidence from Germany

We examine the introduction of a gender quota law in Germany, mandating a minimum 30% of the underrepresented gender on the supervisory boards of a particular type of firms. We exploit the fact that Germany has a two-tier corporate system consisting of the affected supervisory boards and unaffected management boards within the same firm. We find a positive effect on the female share on supervisory boards of affected firms, but no effect on presidency of the board or its size. We also study whether the increased female representation has had an effect on the financial performance of the firm and conclude that, unlike some previous studies in other countries, there has not been any negative effect on the profitability of the firm, neither at the time when the law was announced nor when it was passed

METHODOLOGICAL REFLECTION ON THE HETEROCHRONIA IN THE CONTEXT OF DEVELOPMENT OF A HEALTH PRESERVING COMPETENCE OF A PHYSICAL EDUCATION TEACHER

The article presents the methodology of using knowledge about the phenomenon of heterochronia in pedagogy. The aim of the study is to improve the methodology of development of health-saving competence of Physical Education teacher in postgraduate education based on actualization and understanding of the phenomenon of heterochronia. The use of knowledge about the phenomenon of heterochronia is considered in the context of pedagogical anthropology and conducted within the framework of phenomenological, health-saving and anthropological approaches. Approaches used in the research are the following: competence, axiological, existential, transdisciplinary, etc. Due to the use of the phenomenon of heterochronia, the temporal phenomenology of a person is represented, as well as its non-linearity, processability. Knowledge of the phenomenon of heterochronia and its value interpretations is used in the pedagogical methodology of prevention of sudden cardiac death. The use of knowledge of heterochronia promotes the effective application of Physical Education teacher the knowledge of human morphophysiology in educational practices of health preservation and axiologicalization and humanization of the educational process. The results of the conducted study determine quite considerable prevalence of knowledge as well as value and health oriented understandings of heterochronia among the working Physical Education teachers in comparison with students mastering this profession

Taxonomy of Asteroids From the Legacy Survey of Space and Time Using Neural Networks

The Legacy Survey of Space and Time (LSST) is one of the ongoing or future surveys, together with the Gaia and Euclid missions, which will produce a wealth of spectrophotometric observations of asteroids. This article shows how deep learning techniques with neural networks can be used to classify the upcoming observations, particularly from LSST, into the Bus-DeMeo taxonomic system. We report here a success ratio in classification up to 90.1% with a reduced set of Bus-DeMeo types for simulated observations using the LSST photometric filters. The scope of this work is to introduce tools to link future observations into existing Bus-DeMeo taxonomy.Peer reviewe

Spintronics of a Nanoelectromechanical Shuttle

We consider effects of the spin degree of freedom on the nanomechanics of a single-electron transistor (SET) containing a nanometer-sized metallic cluster suspended between two magnetic leads. It is shown that in such a nanoelectromechanical SET(NEM-SET) the onset of an electromechanical instability leading to cluster vibrations and "shuttle" transport of electrons between the leads can be controlled by an external magnetic field. Different stable regimes of this spintronic NEM-SET operation are analyzed. Two different scenarios for the onset of shuttle vibrations are found.Comment: 4 pages, 3 figure