Decision of mathematical logical tasks in sensory enriched environment (classical music)

The time of a decision of mathematical logical tasks (MLT) was decreased during classical musical accompaniment (power 35 and 65 dB). Music 85 dB did not influence on the process of decision of MLT. Decision without the musical accompaniment led to increasing of coherent function values in beta1, beta2, gamma frequency ranges in EEG of occipital areas with prevalence in a left hemisphere. A coherence of potentials was decreased in EEG of frontal cortex. Music decreasing of making-decision time enhanced left-sided EEG asymmetry The intrahemispheric and the interhemispheric coherences of frontal cortex were increased during the decision of MLT accompanied by music. Using of musical accompaniment 85 dB produced a right-side asymmetry in EEG and formed a focus of coherent connections in EEG of temporal area of a right hemisphere.     

EEG in mathematical logical problem solving

The model of mathematical logic tasks was developed at which decision there was a value coherence in delta-range raised. In low-frequency ranges (delta, theta, and alpha) a coherence of potentials of frontal cortex were increased. In high-frequency ranges (beta1, beta2, gamma) in frontal cortex coherence was decreased, and its increasing in central, parietal, temporal, and occipital areas with prevalence in the left hemisphere. Most changes of quantity of positive connections observed in value diagonal coherence. Analysis of spectral power EEG has shown, that at the decision of tasks there is a generalised raising on a cortex in delta-range. Theta-activity increased in a frontal cortex, and gamma band was raised in occipital areas. A spectral power in an alpha range mainly decreased.     

Corvidae are able to understand the logical structure in string-pulling tasks

The ability of the Corvidae to understand the logical structure in string-pulling tasks was studied in a set of experiments with varied position of strings. It was demonstrated that some hooded crows (Corvus cornix L.) and common ravens (Corvus corax L.) successfully completed the tasks where the strings were not intersected but placed so that the bait was positioned opposite the forepart of the empty string. Hooded crows also solved the task where the baits were attached to both strings, but one of the strings was disrupted. The task with two intersected strings where the bait was positioned opposite the forepart of the empty string was not solved by the crows. The results suggest the ability of both examined species to grasp the logical structure of such kind of tasks.     

Informational properties of neural nets performing algorithmic and logical tasks

It is argued that the genetic information necessary to encode an algorithmic neural processor tutoring an otherwise randomly connected biological neural net is represented by the entropy of the analogous minimal Turing machine. Such a near-minimal machine is constructed performing the whole range of bivalent propositional logic in variables. Neural nets computing the same task are presented; their informational entropy can be gauged with reference to the analogous Turing machine. It is also shown that nets with one hidden layer can be trained to perform algorithms solving propositional logic by error back-propagation. Received: 30 June 1995 / Accepted in revised form: 9 January 1996     

Influence of music on heart rate variability and comfort--a consideration through comparison of music and noise

By considering three kinds of music and noise, this research investigates the influence of music on the living body by comparing the difference of influence on heart rate variability and comfort when subjects listen to music and are exposed to noise. We used two pieces of classical music, rock music, and noise recorded by a tape recorder. The following conclusions were made from the findings of the research: 1) Hearing classical music results in a small variance of Mayer Wave related Sinus Arrhythmia (MWSA) component and Respiratory Sinus Arrhythmia (RSA) component compared with a body being at rest. This is because the sympathetic nerve is suppressed by the sound of classical music. With rock music and noise, however, the MWSA component increases and the RSA component decreases. 2) From a psychological evaluation, we found that classical music tends to cause comfort and rock music and noise tend to cause discomfort. 3) A correlation was found between the balance of the MWSA component and the RSA component and the psychological evaluation. As the comfort increases, the variance of MWSA decreases; as discomfort increases, the variance of MWSA increases.     

A mathematical model for the uptake of ions from the soil solution

Summary A model is developed in which the uptake of ions which exist wholly in the soil solution is described in terms of their net movement towards the surfaces of roots. The ions are assumed to move either by diffusion, or in the mass flow of water towards the roots, and, given these two ways of movement, the model is based on five main assumptions. The validity of these assumptions is discussed, together with some of the model's implications, and a few experiments are suggested by which it could be tested.     

On the solution of mathematical models of herd immunity in human helminth infections

The general solution of the mathematical model of herd immunity to human helminth infections recently proposed by Anderson and May [3] is obtained. The numerical solution of a more accurate biological model is indistinguishable from the corresponding exact solution of a more tractable mathematical model. Computer simulations of some particular cases of this model support the notion that both ecological and immunological factors determine the observed convex patterns of age-prevalence and age-intensity curves of human helminth infections.This work was made thanks to the advise and support of Dr. Robert M. May while the author was Postdoctoral Fellow at Princeton University     

Influence of viscosity on myocardium mechanical activity: a mathematical model

We have previously proposed and validated a mathematical model of myocardium contraction-relaxation cycle based on current knowledge of regulatory role of Ca2+ and cross-bridge kinetics in cardiac cell. That model did not include viscous elements. Here we propose a modification of the model, in which two viscous elements are added, one in parallel to the contractile element, and one more in parallel to the series elastic element. The modified model allowed us to simulate and explain some subtle experimental data on relaxation velocity in isotonic twitches and on a mismatch between the time course of sarcomere shortening/lengthening and the time course of active force generation in isometric twitches. Model results were compared with experimental data obtained from 28 rat LV papillary muscles contracting and relaxing against various loads. Additional model analysis suggested contribution of viscosity to main inotropic and lusitropic characteristics of myocardium performance.     

Influence of anions on the properties of microbial polysaccharides in solution

The order-disorder transition temperatures of the polysaccharides succinoglycan and xanthan are strongly influenced by the salts present in solution. High concentrations of anions such as bromide or thiocyanate lower the transition temperature, thus decreasing the stability of the polymer and increasing its susceptibility to acid catalysed degradation. Salts such as sulphate and phosphate raise the transition temperature but can cause precipitation, and result in the incompatibility of the polymers with certain brines. The effects are in line with the Hofmeister or lyotropic series. The two polysaccharides seem to fit into a spectrum including other biopolymers such as some proteins, although not DNA even though its behaviour is qualitatively similar. The effects arise from the interaction of the salts, primarily the anions, with the solvent water. The hydropholic nature of carbohydrates enables them to structure the solvent to a higher temperature than proteins. The importance of the effect of the polymer on the solvent in considering structure-property relationships cannot the overstressed.     

Influence of uracil on the conformational behaviour of RNA oligonucleotides in solution

NMR studies were carried out on some alternating pyrimidine-purine sequences: the single-stranded tetramers CACA and UGUG and the self-complementary octamer CACAUGUG. Assignments, based upon COSY, homonuclear Hartmann-Hahn, and NOESY experiments, are given for the resonances of all base protons and of several sugar protons. Chemical shift vs temperature profiles were used to obtain thermodynamic parameters for the single-stranded stack in equilibrium with random coil and the duplex in equilibrium with random coil equilibria. The populations of N-type conformer of the ribose rings were estimated from the observed J1'2'. Comparisons with another alternating pyrimidine-purine sequence Um2(6)AUm2(6)A and with the deoxyribose counterparts d(CACA), d(TGTG) and d(CACATGTG) are given. Previous 1H-NMR investigations of Um2(6)AUm2(6)A revealed that the population of bulge-out structure diminishes compared to m2(6)AUm2(6)A due to the U(1)-m2(6)A(2) stacking interaction. In CACA a strong stacking proclivity (Tm = 310 K) together with a clear preference for N-type ribose is observed. However, the stacking interactions in UGUG are relatively less stable (Tm = 288 K) and a bias towards S-type sugar is present. Besides a small amount of stack, a significant contribution of bulge out structure is proposed for UGUG. We conclude that the nature of the pyrimidine base mainly determines the formation of bulge-out structures. The poor stacking properties of uracil now appear to be mainly responsible for this phenomenon. Comparison with the deoxyribose counterparts shows a reasonable agreement between the Tm values of CACA and d(CACA), whereas the Tm of UGUG (288 K) is much lower than the Tm of d(TGTG) (315 K). It is suggested that the absence of bulge-out structures in DNA purine-pyrimidine-purine sequences is related to the relatively strong stacking proclivity of dT residues compared to that of U residues. The Tm values (average 341 K) for the duplex in equilibrium with random coil transition obtained for each residue of CACAUGUG appear very similar. All ribose rings, except the G(8), adopt a pure N conformer in the duplex. This is taken to mean that the differences in conformational behaviour of the constituent tetramers disappear upon duplex formation.     

Influence of the pyruvate content of xanthan on macromolecular association in solution

The unusual increase in viscosity and pseudoplasticity often observed when salts are added to moderately concentrated aqueous solutions of xanthan gum is shown to arise from an increase in the extent of macromolecular association. The fractional change in viscosity on addition of KCl to salt-free 1% (w/v) solutions of purified polysaccharide in the K⁺ salt form is found to be positive only when the degree of pyruvate substitution (fraction of side chains which carry pyruvate ketal substituents) exceeds ≈0.31. Above this value, the fractional change in viscosity increases with further increase in the degree of pyruvate substitution. These differences cannot arise from different degrees of conformational ordering, since the magnitude of the thermally induced order disorder transition (monitored by optical rotation at low ionic strength) is independent of pyruvate content. The temperature at the transition midpoint, however, falls with increasing degree of pyruvate substitution. This is attributed to destabilization of the ordered structure by intramolecular electrostatic repulsion between pyruvate groups, and stabilization through apolar interactions of acetate methyl groups. Viscosity-concentration relationships show changes of slope which mark the onset of macromolecular association. Association commences at lower concentrations when ionic strength and degree of pyruvate substitution are high. It is suggested that once electrostatic repulsions have been diminished at high ionic strength, association is promoted by intermolecular apolar interactions of pyruvate methyl groups, which are suitably near the periphery of the helical conformation.     

The problem of determining the affinity of bivalent antibodies using ELISA and its mathematical solution]

A new approach for the determination of the affinity of monovalent receptors in direct coordinates could be obtained without using Klotz or Scatchard equations. The mathematical solution of the problem of the determination of the affinity of bivalent antibodies by ELISA gives the following relation between absorbance, measured in ELISA. and antigen concentration: omega + square root of omega 2 + omega = liK, where omega = (Ao-Ai)/Ai, Ai is the absorbance, if Ag concentration is equal li; Ao is the absorbance, if Ag concentration is equal zero, K is an equilibrium constant.