Some anthropologic factors of performance in rhythmic gymnastics novices

The aim of the study was to determine motor and morphological factors, and to assess their impact on specific motor skill performance in rhythmic gymnastics (RG). Experimental training process aimed at learning and improving basic movement structures of rhythmic gymnastics was performed for nine months in a sample of 50 female rhythmic gymnastics novices (mean age 7.1 +/- 0.3 years). Seven dimensions in total were isolated by factorial analysis of 13 motor, 11 morphological, and 20 specific rhythmic gymnastics tests. The factors of flexibility (Beta = 0.26; p < 0.05), explosive strength (Beta = 0.25; p < 0.05) and adipose voluminosity (Beta = -0.42; p < 0.001) explains 41% of the success in performing RG basic body elements--jumps, rotations, balance and flexibility (R = 0.64), while the frequency of movement (Beta = 0.44; p < 0.001) and non-adipose voluminosity (Beta = 0.26; p < 0.05) explains 26% of RG-specific manipulations with the apparatus--club, ribbon and ball wrist manipulation (R = 0.52; p < 0.01). According to study results, the RG-training process intended for rhythmic gymnastics novices should be programmed, with preset objectives for the development of flexibility and explosive strength, speed and peripheral joint strength and adipose tissue reduction.     

Effect of thyroidectomy on rhythmic gonadotropin release.

Nonstress blood samples were obtained from intact and thyroidectomized (TE) male rats at 3-hr intervals over a 24-hr period via rapid decapitation. The animals were thyroidectomized when 40 days old and used 6 weeks later. Intact animals showed periodicity in serum LH (P less than 0.01) and prolactin (P less than 0.01). Both gonadotropins began increasing after 8 PM and peak levels occurred at 11 PM. In contrast, 24-hr periodicity was not observed in serum FSH. Corticosterone levels in these same serum samples showed the expected circadian periodicity. After TE, the 24-hr pattern in all gonadotropins was altered significantly. Serum LH increased (P less than 0.01) and circadian periodicity appeared to be absent. FSH and prolactin levels were increased and decreased, respectively (P less than 0.01), with serum prolactin showing a 9-hr phase shift. Prolactin began increasing at 2 AM and reached a peak at 8 AM. Corticosterone in TE animals showed a 24-hr rhythm similar to that of intact rats. These findings confirm our previous observations that nonstress serum LH and prolactin levels fluctuate with a 24-hr periodicity and suggest that the level of, and the phase angle betweeen, these rhythms is markedly influenced by pituitary-thyroid activity.     

Recurrence risks for near relatives of children with sensori-neural deafness

In a sample of children with sensori-neural deafness and no evidence of a syndrome, ototoxic exposure, or autosomal dominant or X-linked family history, seen in the Division of Medical Genetics of The Montreal Children's Hospital, the probability of a sibling being similarly affected was about 1 in 6, both in French-Canadian families and the remainder of the sample. The frequency of deafness of early onset was measured in the uncles and aunts of probands, and these figures were used to derive approximate recurrence risks for the offspring of probands (about 1 in 130, ignoring the possibility of autosomal dominant mutation) and for the offspring of the probands' unaffected sibs (about 1 in 250). A rough estimate of the number of autosomal recessive loci contributing to sensori-neural deafness is derived as 13.     

Effect of "animal hypnosis" on the rhythmic defensive dominanta

A defensive dominanta (stationary excitation focus) in the sensorimotor cortex of rabbits was formed by rhythmical electrodermal paw stimulation with the frequency of 0.5 Hz. After cessation of the stimulation, the state of hidden excitation was tested with acoustic stimuli, in response to which nonrhythmic activity of leg muscles increased or the leg rhythmically startled with the frequency close to that of the electrodermal stimulation. After conducting a routine hypnotizing procedure, the incidence of the rhythmic responses to testing stimulation increased, while the incidence of nonrhythmic responses decreased.     

Environmental effects on the subjective perception of level of arousal and the human body temperature rhythm

Subjective estimates of arousal and oral temperature were investigated in a group of young male and female office workers in a constant thermal environment. The measures of arousal were obtained over the period from before rising in the morning until just before sleep in the evening and the results were compared to recently published data in the literature. This comparison indicates a decrease in arousal in this group of subjects and the possible implications of these findings for the artificial control of the thermal environment are discussed.     

Endogenous light-on rhythm in respiration of a long-day duckweed, Lemna gibba G3 II. On basic and rhythmic components of the rhythm

Effects of respiratory substrates (glucose, malate, citrateand pyruvate) and inhibitors (fluoride, iodoacetate, azide andDNP) on the O₂-uptake rhythm in a long-day duckweed,Lemna gibbaG3 in continuous light period were examined. Rates of O₂-uptake at the starting point (6 hr after the beginningof a continuous light period) and at the time of the first peakof the rhythm (18 hr after the beginning of a continuous lightperiod) were equally increased by exogenous substrates. Sensitivityof respiration to fluoride or iodoacetate was almost the sameat the 6th and 18th hr. The O₂-uptake (at the 6th, 18th, 30thand 42nd hr) was increased by DNP by the same amount. Azideat lower concentrations than 5X10^–4 M did not affect O₂-uptakeat the 6th hr, but inhibited uptake at the 18th hr. In the presenceof 5 X 10^–4 M of azide the rates of O₂-uptake at the 18th,30th or 42nd hr were down to the rate at the 6th hr, which wasinsensitive to azide. These results suggest that the O₂-uptakerhythm consists of two components, i.e. the basic respirationwhich is promoted by exogenous substrate, sensitive to DNP andinsensitive to azide; and rhythmic respiration, which is sensitiveto azide, but is not influenced by exogenous substrate and DNP. (Received February 19, 1971; )     

Effect of vanadate on rhythmic leaflet movement in albizzia julibrissin

Vanadate (Na₃VO₄) selectively and reversibly affects the rhythmic movement of Albizzia julibrissin leaflets. Leaflets floated on 1 millimolar vanadate open at the same rate or more rapidly than controls, but closure is inhibited. After 6 to 24 hours incubation, the inhibition can be reversed by a 24-to 48-hour period on water or control buffer. Recovery is complete in light-dark cycles, and it is almost complete under free-running conditions (prolonged darkness). Leaflets floated on 10 millimolar vanadate do not open in darkness, but they open at a reduced rate in light. Concentrations of 100 micromolar or less are ineffective.     

Dynamics of heart rhythm in chimpanzees during the perception of the emotionally colored human voice

The performed study allowed to observe in two chimpanzees both common and individual changes of the heart rate under the action of human voice with emotionally positive or negative intonation, as well as under the action of preferred (sweet) or rejected (quinine solution) natural stimulus. The common property consists in a significant slowing down of the heart rate in response to negative vocal signal and rejected natural stimulus and in only slight change of the heart rate in response to positive signals. Individual properties comprise differences in reactions of the cardiovascular system of both animals to negative action: a greater efficiency of the vocal signal for one chimpanzee and of the direct (natural) stimulus for the second one.     

Effect of the delta-sleep peptide on parasympathetic regulation of the cardiac rhythm

Effect of delta-sleep peptide (60 nM/kg) on the parasympathetic regulation of cardiac activity has been studied in the experiments on rabbits. It has been established that intravenous administration of this peptide to voluntary-behaving animals results in heart rate reduction by an average of 16%, that can be eliminated by atropine. Delta-sleep peptide has been demonstrated to intensify negative chronotropic effect in the case of directly irritated wandering nerve. The data obtained explain a protective effect of delta-sleep peptide on the heart under emotional stress.     

Effect of emotional stress on the cardiac rhythm variability in rats

A degree of irregularities of the heart rhythm was studied by two methods: chaos-analysis and the HRV (heart rate variability) analysis. Our study shows an individual response in 3 groups of animals: 1--animals with low initial level of chaos (correlation dimension (PD2 < 2); 2--animals with high level of chaos (PD2 > 4); and animals with middle level of chaos (2 < PD2 < 4). The first two groups proved to be more sensitive to stress than the third group. Moreover we found that the electrical stability of the heart as measured by the fibrillation threshold, was higher for the chaos third group. The animals of the first two groups had low cardiac stability and high risk of stress-induced cardiac disturbances.