The all-sky GEOS RR Lyr survey with the TAROT telescopes. Analysis of the Blazhko effect

We used the GEOS database to study the Blazhko effect of galactic RRab stars. The database is continuously enriched by maxima supplied by amateur astronomers and by a dedicated survey by means of the two TAROT robotic telescopes. The same value of the Blazhko period is observed at different values of the pulsation periods and different values of the Blazhko periods are observed at the same value of the pulsation period. There are clues suggesting that the Blazhko effect is changing from one cycle to the next. The secular changes in the pulsation and Blazhko periods of Z CVn are anticorrelated. The diagrams of magnitudes against phases of the maxima clearly show that the light curves of Blazhko variables can be explained as modulated signals, both in amplitude and in frequency. The closed curves describing the Blazhko cycles in such diagrams have different shapes, reflecting the phase shifts between the epochs of the brightest maximum and the maximum O-C. Our sample shows that both clockwise and anticlockwise directions are possible for similar shapes. The improved observational knowledge of the Blazhko effect, in addition to some peculiarities of the light curves, have still to be explained by a satisfactory physical mechanism.Comment: 13 pages, 12 figures, accepted for publication in Astronomical Journa

Functional Sensory-Motor Performance Following Long Term Space Flight: The First Results of "Field Test" Experiment

The effect that extended-duration space flights may have on human space travelers, including exploration missions, is widely discussed at the present time. Specifically, there is an increasing amount of evidence showing that the physical capacity of cosmonauts is significantly reduced after long-duration space flights. It is evident that the most impaired functions are those that rely on gravity, particularly up right posture and gait. Because of the sensorimotor disturbances manifested in the neurology of the posture and gait space flight and postflight changes may also be observed in debilitating motion sickness. While the severity of particular symptoms varies, disturbances in spatial orientation and alterations in the accuracy of voluntary movements are persistently observed after long-duration space flights. At this time most of the currently available data are primarily descriptive and not yet suitable for predicting operational impacts of most sensorimotor decrements observed upon landing on planetary surfaces or asteroids. In particular there are no existing data on the recovery dynamics or functionality of neurological, cardiovascular or muscle performance making it difficult to model or simulate the cosmonauts' activity after landing and develop the appropriate countermeasure that will ensure the rapid and safe recovery of crewmembers immediately after landing in what could be hostile environments. However and as a starting position, the videos we have acquired during recent data collection following the long duration flights of cosmonauts and astronauts walking and performing other tasks shortly after return from space flight speak volumes about their level of deconditioning. A joint Russian-American team has developed a new study specifically to address the changes in crewmembers performance and the recovery of performance with the intent of filling the missing data gaps. The first (pilot) phase of this study includes recording body kinematics and quantifying the coordination and timing of relatively simple basic movements - transition from seated and prone positions to standing, walking, stepping over obstacles, tandem walking, muscle compliance, as well as characteristics of postural sway and orthostatic tolerance. Testing for changes in these parameters have been initiated in the medical tent at the landing site. The first set of experiments showed that during the first hour after landing, cosmonauts and astronauts were able to execute (although slower and with more effort than preflight) simple movements such as egress from a seated or prone position and also to remain standing for 3.5 minutes without exhibiting pronounced cardiovascular changes. More challenging tests, however, demonstrated a prominent reduction in coordination - the obstacle task, for example, was performed at much slower speed and with a marked overestimation of the obstacle height and tandem walking was greatly degraded suggesting significant changes in proprioception, brainstem and vestibular function. There is some speculation that the neural changes, either from the bottom-up or top down may be long lasting; requiring compensatory responses that will modify or mask the adverse responses we have observed. Furthermore, these compensatory responses may actually be beneficial, helping achieve a more rapid adaptation to both weightlessness and a return to earth

27 Al NMR/MRI Studies of the Transport of Granular Al 2 O 3

The NMR/MRI techniques are applicable to the studies of motion of granular solids, providing information on the velocities, effective diffusivities and correlation times of the moving particles. The studies of transport of granular solids reported to-date are based on the detection of the 1H NMR signal of the liquid phase of liquid-containing solid materials. Yet, the solid phase of many granular solids contains magnetic nuclei, providing in principle an opportunity to study motion of such solids by directly detecting the NMR signal of the solid phase. In this paper, we demonstrate that this can be performed with the use of conventional echo pulse sequences in combination with the conventional motion encoding schemes. The detection of the 27Al NMR signal of the Al2O3 powder was used to obtain velocity maps of the powder packed in a spinning cylinder, and to measure the velocity distribution (average propagator) for the gravity driven transport of the same powder in a vertical pipe

VENTURE ECOSYSTEM IN RUSSIA AND THE UNITED STATES: A COMPARATIVE ANALYSIS

The aim of the research is to analyse the features of development and current state of the main elements of venture ecosystem in Russia and the United States. To achieve this goal, the authors reveal and analyse the key features of the studied natural ecosystems. The paper considers the chronology of the stages of development of venture ecosystems in both countries, determines their current state, including the volume and number of concluded venture transactions, their ratio by stages of the investment process. The article highlights the key differences between socio-cultural factors and legal frameworks that regulate and influence the activities of venture ecosystems. The study identifies the main problematic aspects of the development of the innovative potential of the Russian Federation and the reasons for their occurrence. The authors carry out a comparative analysis of the venture industry in Russia and the United States, identify on its basis, the key problems that hinder the development of the venture ecosystem in Russia, and give recommendations for overcoming

Polarization switching kinetics at the nanoscale in ferroelectric copolymer Langmuir-Blodgett films

The polarization switching kinetics of ferroelectric Langmuir–Blodgett films of vinylidene fluoride-trifluoroethylene copolymer were investigated by piezoresponse force microscopy with a resolution of 100 nm. The switching time in response to a localized voltage pulse exhibits an exponential dependence on reciprocal voltage, which is consistent with nucleation-limited switching dynamics

Review of modern silicone and epoxy plastination methods for the brain

In the educational process of medical and veterinary higher educational institutions, cadaveric material is actively used, which is difficult to obtain and preserve for a long time. One of the solutions for long-term preservation of educational material is the production of preparations from them using silicone and epoxy plastination methods. In this case, methods for preserving brain preparations are of value, which initially, due to its soft structure, is easily destroyed during the educational process. The article discusses new methods of brain plastination based on a sample of scientific data from PUBMED, Elibrary, Google Scholar for the period from 2017 to 2024. 14 articles from a sample of 1095 articles were analyzed. Currently, several authors propose new methods using polyester resins, additional staining for contrasting the gray and white matter of the brain, new methods of placing in acrylic boxes and creating 3D-models, processing with corn starch and enclosing in transparent thermal film, impregnation with gum arabic or paraffin, combining various plastics during plastination to improve the performance properties of the preparations

27 Al NMR/MRI Studies of the Transport of Granular Al 2 O 3

The NMR/MRI techniques are applicable to the studies of motion of granular solids, providing information on the velocities, effective diffusivities and correlation times of the moving particles. The studies of transport of granular solids reported to-date are based on the detection of the 1H NMR signal of the liquid phase of liquid-containing solid materials. Yet, the solid phase of many granular solids contains magnetic nuclei, providing in principle an opportunity to study motion of such solids by directly detecting the NMR signal of the solid phase. In this paper, we demonstrate that this can be performed with the use of conventional echo pulse sequences in combination with the conventional motion encoding schemes. The detection of the 27Al NMR signal of the Al2O3 powder was used to obtain velocity maps of the powder packed in a spinning cylinder, and to measure the velocity distribution (average propagator) for the gravity driven transport of the same powder in a vertical pipe

Biochemical and antioxidant characteristics of the soil strain Chlorococcum oleofaciens (Chlorophyceae, Chlorophyta) grown in light, dark and bicarbonate conditions

This study aimed to examine the biochemical and antioxidant characteristics of a soil strain of Chlorococcum oleofaciens CAMU MZ–Ch4 (Chlorophyceae, Chlorophyta) when cultured in light, darkness, and a combination of light-bicarbonate and dark-bicarbonate in an acute 96-hour experiment. The study established that cultivation in the dark is accompanied by an increase in the antioxidant status of Chlorococcum oleofaciens CAMU MZ–Ch4 strain cells, which is associated with the accumulation of low-molecular antioxidants and the activation of antioxidant enzymes. Culturing in the dark also causes the accumulation of chlorophyll a, ascorbic acid, astaxanthin, and lipids. But biomass productivity and concentration decreased. Introducing NaHCO3 into the medium inhibits the biosynthesis and accumulation of α-tocopherol, ascorbic acid, phenolic compounds, and chlorophylls both under illuminated and in the dark. The intensity of lipid peroxidation decreases and the activity of antioxidant enzymes increases under light and in the dark conditions with NaHCO3 in the medium