Methods and software for cosmic ray scintillation studies

The principal instrument used in cosmic ray scintillation studies is the spectra constructed from intensive observation. This method has its drawbacks in that the statistical characteristics of the process undergo essential reconstruction, i.e., the process becomes nonstationary from the viewpoint of such phenomena as Forbush decrease and during solar flares. The software used to process the above includes the direct Fourier transform and its modifications, autoregressive processes, and instantaneous spectrum methods. Used in various combinations, they prove helpful in handling the time series

Neutrino-antineutrino annihilation around collapsing star

Stellar collapse is accompanied by emission of E sub neutrino approximately 10 MeV neutrinos and antineutrinos with the energy output W sub neutrino approximately 10 to the 53rd power to 10 to the 54th power erg. Annihilation of these particles in the vicinity of collapsar is considered. The physical consequences are discussed

Study of cosmic ray scintillations from 5-minute data of the scintillations telescope Izmran and world-wide network stations

During cosmic ray propagation in interplanetary space there appear characteristic cosmic-ray intensity scintillations which are due to charged particle scattering on random inhomogeneities of the interplanetary magnetic field. The power spectra of cosmic ray scintillations on the Earth during some intervals from 1977 to 1982 (for quiet periods, for solar flares and Forbush decreases due to power shock waves) have been calculated from five-minute, one and two-hour values of the cosmic-ray intensity measured by the scintillator supertelescope IZMIRAN. The spectra were estimated by the methods of spectral analysis and by autoregressive methods which mutually control each other and make it possible not only to analyze scintillation powers at distinguished frequencies, but also to determine the behavior of spectrum slopes in some frequency ranges

The gamma-ray telescope Gamma-1

French and Soviet specialists have designed and built the gamma-ray telescope GAMMA-1 to detect cosmic gamma rays above 50 MeV. The sensitive area of the detector is 1400 sq cm, energy resolution is 30% at 300 MeV, and angular resolution 1.2 deg at 300 MeV (and less than 20' arc when a coded aperture mask is used). Results on calibration of the qualification model and Monte-Carlo calculations are presented

Method for Estimation of Quality Sports of Technique Diagnostics of Technical Mistakes

In the present paper criteria of efficient running technique at a maximal speed have been determined. The authors assume as efficient the technique which provides the same performance by less mechanical energy cost. The purpose of the study is to answer the question about how to run (what kinematic, dynamic and energy characteristics should be) to provide an efficient running technique. To investigate the efficiency of technique two methods -one of regression residuals and the other of discriminative features, are widely used. Regression residuals method [2] allows to differentiate between athletes «good at technique» and athletes «no good at technique». The merit of the method lies in the absence of motor potential influence on technique assessment. However the method does not provide technique criteria, i.e. biomechanical characteristics of the motion necessary for higher performance at the same motor potential level. The discriminative features method [1] allows to determine technique criteria by their comparison in highly-and low-qualified athletes with the same motor potential. The authors suggest combination of the above methods for technique criteria determination. That will enhance their merits and eliminate drawbacks. At first, using the regression residuals method the subjects have been divided into groups of athletes good at technique and athletes no good at technique. Then the discriminative features method has been used, i.e. biomechanical motion characteristics have been compared in the groups of athletes good and no good at technique. Those characteristics that differ significantly in both groups have been taken for technique criteria, criteria choice being independent on athletes' motor potential

How do treadmill speed and terrain visibility influence neuromuscular control of guinea fowl locomotion?

Locomotor control mechanisms must flexibly adapt to both anticipated and unexpected terrain changes to maintain movement and avoid a fall. Recent studies revealed that ground birds alter movement in advance of overground obstacles, but not treadmill obstacles, suggesting context-dependent shifts in the use of anticipatory control. We hypothesized that differences between overground and treadmill obstacle negotiation relate to differences in visual sensory information, which influence the ability to execute anticipatory manoeuvres. We explored two possible explanations: (1) previous treadmill obstacles may have been visually imperceptible, as they were low contrast to the tread, and (2) treadmill obstacles are visible for a shorter time compared with runway obstacles, limiting time available for visuomotor adjustments. To investigate these factors, we measured electromyographic activity in eight hindlimb muscles of the guinea fowl (Numida meleagris, N=6) during treadmill locomotion at two speeds (0.7 and 1.3 m s−1) and three terrain conditions at each speed: (i) level, (ii) repeated 5 cm low-contrast obstacles (90% contrast, black/white). We hypothesized that anticipatory changes in muscle activity would be higher for (1) high-contrast obstacles and (2) the slower treadmill speed, when obstacle viewing time is longer. We found that treadmill speed significantly influenced obstacle negotiation strategy, but obstacle contrast did not. At the slower speed, we observed earlier and larger anticipatory increases in muscle activity and shifts in kinematic timing. We discuss possible visuomotor explanations for the observed context-dependent use of anticipatory strategies

A dynamical systems analysis of afferent control in a neuro--mechanical model of locomotion

Existing models have represented a locomotor system as a rhythmic driver, or central pattern generator (CPG), coupled to a mechanical limb, with feedback closing the loop. Our collaborators have developed a version of this model in which the CPG establishes a rhythm when activating drive is present, and feedback from ground strike helps control phase switching and rhythm stabilization. Spinal cord injury can be simulated through termination of drive, which ceases the rhythm. We derive and analyze a reduced representation of this model, which will elucidate general principles of phase and frequency control in normal locomotion. We aim to understand how the presence of feedback provides stable locomotion, allowing oscillations at a wider range of drive values to the CPG (specifically at lower values) than the CPG without afferent feedback. Furthermore, increasing the drive intensity to the CPG increases locomotor speed by reducing only the duration of the stance phase, at a relatively constant duration of swing phase [1]. This phase asymmetry has been seen in normal locomotion in cats, rats, and humans, but is not observed in the locomotor model without feedback, so we analyze how feedback facilitates this asymmetry. We will also reveal sufficient conditions for recovering rhythmicity in the injured state - how in the absence of drive, increased feedback can restore locomotion and contribute to locomotor stability, with an analysis of differences in rhythm robustness before and after loss of drive

Paw-shake Response and Locomotion: Can One CPG Generate Two Different Rhythmic Behaviors?

Using software AnimatLab we developed a 5-segment cat hindlimb model with 12 Hill-type muscle actuators controlled by (1) a half-center CPG activating flexor and extensor muscles (two-joint muscles received both flexion- and extension-related signals) and (2) proprioceptive input originated from the muscle spindle and Golgi tendon organ afferents