On the influence of noise on chaos in nearly Hamiltonian systems

The simultaneous influence of small damping and white noise on Hamiltonian systems with chaotic motion is studied on the model of periodically kicked rotor. In the region of parameters where damping alone turns the motion into regular, the level of noise that can restore the chaos is studied. This restoration is created by two mechanisms: by fluctuation induced transfer of the phase trajectory to domains of local instability, that can be described by the averaging of the local instability index, and by destabilization of motion within the islands of stability by fluctuation induced parametric modulation of the stability matrix, that can be described by the methods developed in the theory of Anderson localization in one-dimensional systems.Comment: 10 pages REVTEX, 9 figures EP

Incoherent Interplane Conductivity of kappa-(BEDT-TTF)2Cu[N(CN)2]Br

The interplane optical spectrum of the organic superconductor kappa-(BEDT-TTF)2Cu[N(CN)2]Br was investigated in the frequency range from 40 to 40,000 cm-1. The optical conductivity was obtained by Kramers-Kronig analysis of the reflectance. The absence of a Drude peak at low frequency is consistent with incoherent conductivity but in apparent contradiction to the metallic temperature dependence of the DC resistivity. We set an upper limit to the interplane transfer integral of tb = 0.1 meV. A model of defect-assisted interplane transport can account for this discrepancy. We also assign the phonon lines in the conductivity to the asymmetric modes of the ET molecule.Comment: 7 pages with embedded figures, submitted to PR

Comparative analysis of assessment methods for operational and anesthetic risks in ulcerative gastroduodenal bleeding

Aim of the investigation: to conduct a comparative analysis of methods of evaluation of surgical and anesthetic risks in ulcerative gastroduodenal bleeding. Materials and methods. A retrospective analysis ofthe extent of the surgical and anesthetic risks and results of treatment of 71 patients with peptic ulcer bleeding has been conducted in the study. To evaluate the surgical and anesthetic risks classification trees are used, scale ТА. Rockall and prognosis System of rebleeding (SPRK), proposed by N. V. Lebedev et al. in 2009, enabling to evaluate the probability of a fatal outcome. To compare the efficacy ofthe methods the following indicators are used: sensitivity, specificity and prediction of positive result. Results. The study compared the results ofthe risk assessment emergency operation by using these methods with the outcome ofthe operation. The comparison ofthe prognosis results in sensitivity leads to the conclusion that the scales ТА. Rockall and SPRK are worse than the developed method of classification trees in recognizing patients with poor outcome of surgery. Conclusion. The method of classification trees can be considered as the most accurate method of evaluation of surgical and anesthetic risks in ulcerative gastroduodenal bleeding

TREATMENT OF INFANTS WITH REPEATED BACTERIAL INFECTIONS OF RESPIRATORY TRACT AND ENT-ORGANS WITH LYSATES MIXTURE

The article presents the results of a study, evaluating effectiveness of therapeutic use of bacterial lysates for the topical administration (IRS 19) in children under the age 3–9 months old. All children had repeated bacterial diseases of ENT-organs and respiratory tract; it is the clinical sign of immunological reactivity disorder in infants, which is estimated as so-called «syndrome of anti-infection defense disorder». Administration of drug resulted in decrease of rate and duration of infectious episodes in upper and lower airways, excluded the need of antibacterial treatment of these children. This effect is concerned with increase of resistance of children’s organism and indirect correction of previously detected immune disorders.Key words: infants, infections of respiratory tract, disorders of anti-infection defense, bacterial lysates mixture.(Voprosy sovremennoi pediatrii — Current Pediatrics. 2009;8(5):40-46

Gender features of autonomic regulation of cardic activity in young athletes

Background. The success of sports activity is related to the level of the athlete's functional state. The analysis of heart rate variability will allow to determine the adaptive capabilities and the state of the reserves of the cardiac activity of the athlete’s body at the present time and to predict the sports result. The purpose of this work is to study the gender characteristics of the autonomic regulation of cardiac activity in child athletes. Materials and methods. The study involved 22 children aged 12 to 18 years. All study participants were divided into 2 groups: group 1 (n = 10) ‒ boys, group 2 (n = 12) ‒ girls. Heart rate, systolic and diastolic blood pressure, body weight, and height were measured noninvasively. We calculated the adaptive potential, body mass index, Kerdo index. For assessment of heart rate variability we calculated the vegetative balance index (VBI), vegetative rhythm index (VRI) and stress index (SI) of regulatory systems. Statistical analysis was performed using t-test, U-test and χ2-test. Results. In both groups, satisfactory adaptation of the cardiovascular system (CVS) to physical activity (AP < 2.6), however, the value of this indicator is higher among boys by 7.25 % (p < 0.001), which may indirectly indicate better functional reserves of the body of girls during adaptation to physical activity. When calculating the Kerdo index and studying heart rate variability (HRV), it was found that 50 % of boys are sympathicotonic and 10 % are parasympathicotonic. Among girls, an increase in the tone of the sympathetic division of the ANS is more common by 8.3 % (p < 0.001). The RRNN value in the boys group is 15 % higher than in the girls group (p < 0.001). The value of NN50 and pNN50 was also higher among boys by 44.87 % and 41.17 %, respectively (p < 0.05). SDNN and RMSSD in the group of girls are less by 25.5 % (p < 0.01) and 34.5 % (p < 0.05), respectively. The mean heart rate is higher among girls by 11.6 % (p < 0.01). IVR, VLOOKUP and IN were higher in the group of girls by 32.8 %, 32.9 % and 50.8 %, respectively (p < 0.01). Conclusions. In both gender groups, satisfactory adaptation of the cardiovascular system to physical activity was revealed. According to linear rhythmograms and columnar histograms, HRV is higher in the boys group, stress indices are higher in the girls group

Prospects of non-drug approaches to Alzheimer's disease

Despite the urgency of the problem of prevention and treatment of neurodegenerative processes underlying Alzheimer's disease (AD) and other severe disorders of the central nervous system, therapeutic and prophylactic potential of drugs is yet insufficient. Numerous adverse effects of the drugs, which might improve cognitive function in patients with AD substantiate serious consideration of measures enhancing adaptive potential and mobilizing self-defense of the body. It is clear now that endogenous defense systems of the brain can limit progression of AD long after the onset of the disease. The measures mobilizing the self-defense include administration of natural adaptogens and various types of adaptation, such as adaptation to dietary restrictions, promotion of physical and mental activity, and adaptation to hypoxia. This review presents data supporting a hypothesis that non-drug activation of self-defense of the body can prevent cognitive decline induced by neurodegenerative processes in the brain by targeting key points of AD pathogenesis

Possible use of adaptation to hypoxia in Alzheimer's disease: A hypothesis

Disorders in memory and other cognitive functions in Alzheimer's disease (AD) may result from an exhaustion of adaptive reserves in the brain. Therefore it is a challenge to find methods to increase the adaptive reserve of the organism to combat AD. Excitotoxicity, Ca2+ homeostasis disruptions, oxidative stress, disturbed synthesis of NO, and impaired cerebral circulation are suggested as key pathogenic factors of AD. At present it appears that stimulation of the self-defense systems in neural cells is a promising strategy in restricting the progression of AD. These systems include those of antioxidants, heat shock proteins (HSPs), NO, and other so-called stress-limiting systems. Non-drug activation of these systems can be achieved most efficiently by adaptation of the organism to environmental challenges, such as hypoxia. In this paper the potential of methods used in adaptive medicine is explored. The protective mechanisms of adaptation to hypoxia may be related to restriction of oxidative stress in the hippocampus, the limitation of a decrease in NO production induced by β-amyloid, and increased density of the vascular network in the brain. In this review we selectively present data that support the idea that adaptation to hypoxia is a possible non-drug means in the prevention of AD. In our opinion this strategy may provide a break-through in the clinical approach of this disease. © Med Sci Monit, 2005

Prospects of non-drug approaches to Alzheimer's disease

Despite the urgency of the problem of prevention and treatment of neurodegenerative processes underlying Alzheimer's disease (AD) and other severe disorders of the central nervous system, therapeutic and prophylactic potential of drugs is yet insufficient. Numerous adverse effects of the drugs, which might improve cognitive function in patients with AD substantiate serious consideration of measures enhancing adaptive potential and mobilizing self-defense of the body. It is clear now that endogenous defense systems of the brain can limit progression of AD long after the onset of the disease. The measures mobilizing the self-defense include administration of natural adaptogens and various types of adaptation, such as adaptation to dietary restrictions, promotion of physical and mental activity, and adaptation to hypoxia. This review presents data supporting a hypothesis that non-drug activation of self-defense of the body can prevent cognitive decline induced by neurodegenerative processes in the brain by targeting key points of AD pathogenesis

Possible use of adaptation to hypoxia in Alzheimer's disease: A hypothesis

Disorders in memory and other cognitive functions in Alzheimer's disease (AD) may result from an exhaustion of adaptive reserves in the brain. Therefore it is a challenge to find methods to increase the adaptive reserve of the organism to combat AD. Excitotoxicity, Ca2+ homeostasis disruptions, oxidative stress, disturbed synthesis of NO, and impaired cerebral circulation are suggested as key pathogenic factors of AD. At present it appears that stimulation of the self-defense systems in neural cells is a promising strategy in restricting the progression of AD. These systems include those of antioxidants, heat shock proteins (HSPs), NO, and other so-called stress-limiting systems. Non-drug activation of these systems can be achieved most efficiently by adaptation of the organism to environmental challenges, such as hypoxia. In this paper the potential of methods used in adaptive medicine is explored. The protective mechanisms of adaptation to hypoxia may be related to restriction of oxidative stress in the hippocampus, the limitation of a decrease in NO production induced by β-amyloid, and increased density of the vascular network in the brain. In this review we selectively present data that support the idea that adaptation to hypoxia is a possible non-drug means in the prevention of AD. In our opinion this strategy may provide a break-through in the clinical approach of this disease. © Med Sci Monit, 2005