RESUMO
The purpose of the communication is to discuss the general properties of developing systems, the methods of their modeling, and the question of their complexity. The concept "complex system" is conditional, a more precise meaning has the complexity of the model describing the phenomenon. Two propositions are discussed: (1) The complexity of basic models is minimal. In other words, complex basic models are not necessary at all. (2) Alive systems are simpler than lifeless. Many processes in the inanimate nature, too, can also be assigned to developing systems. Nevertheless there is a distinction between alive and lifeless systems. The distinction consists in that alive beings can put a purpose before themselves and develop according to it. For this reason, they can be described by simpler basic models.
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Modelos TeóricosRESUMO
The standard theory of the electron transfer between donor and acceptor molecules was used to describe oscillations in the reduction kinetics of the intermediate electron acceptor BA and the primary electron acceptor HA. The kinetics of the reduction of BA and HA were simulated on the basis of the model in which one and two accepting modes were used. A principal experiment is offered for the selection of the suitable theory for adequate description of oscillations in the kinetics of electron transfer in the reaction centers of purple bacteria.
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Complexo de Proteínas do Centro de Reação Fotossintética/química , Rhodobacter sphaeroides/química , Transporte de Elétrons , Cinética , Modelos Teóricos , Teoria QuânticaRESUMO
A concept of the arrangement of the neural computer is proposed, which allows one to solve some problems of modern neural computing and to describe the effects of intuition, creation, as well as a number of effects that are not yet sufficiently understood. The concept is based on the idea that the activity of knowledge acquisition and of information store are complementary and should be performed by two different subsystems, and the subsystem able to learn has to involve the "noise", i.e., an occasional element. The problem is discussed to what extent the artificial intellect could simulate the living one. A set of possible methods are suggested in order to simulate the effects that traditionally were prescribed to the human organism only (the sense of humor, the sleep and dreams, etc.).
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Inteligência Artificial , Intuição , Lógica , Processos Mentais , Criatividade , Humanos , Aprendizagem , Redes Neurais de ComputaçãoRESUMO
The Pareto distribution, whose probability density function can be approximated at sufficiently great chi as rho(chi) - chi(-alpha), where alpha > or = 2, is of crucial importance from both the theoretical and practical point of view. The main reason is its qualitative distinction from the normal (Gaussian) distribution. Namely, the probability of high deviations appears to be significantly higher. The conception of the universal applicability of the Gauss law remains to be widely distributed despite the lack of objective confirmation of this notion in a variety of application areas. The origin of the Pareto distribution in dynamic systems located in the gaussian noise field is considered. A simple one-dimensional model is discussed where the system response in a rather wide interval of the variable can be quite precisely approximated by this distribution.
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Distribuições Estatísticas , Modelos EstatísticosRESUMO
The wording, content, and corollaries of the so-called "kT problem" are considered. The problem points to the paradox of the biological effects of weak low-frequency magnetic fields. The conventional wording of the problem contains implicit assumptions the analysis of which shows their incomplete physical validity.
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Magnetismo , Campos EletromagnéticosRESUMO
The influence of magnetic noise on the dynamics of magnetic nanoparticles under the conditions of stochastic resonance is considered. The effect of the magnetic noise is shown to be equivalent to the growth of the effective thermostat temperature for the particles at the permanent actual temperature of the medium. This regularity may be used for testing the hypothesis on the involvement of magnetic nanoparticles in the formation of biological effects of weak magnetic fields.
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Óxido Ferroso-Férrico/química , Nanoestruturas/química , Magnetismo , Processos Estocásticos , TemperaturaRESUMO
A possible neurophysiological mechanism of the therapeutic effect of weak influences was proposed, which is based on the following assumptions: 1. In the organism, there is an autodiagnostic system, which serves for the accumulation and processing of information on the state of the organs to diagnose a desease. 2. The autodiagnostic disease is a recognizing system, i. e., a neuronet, which is constructed and functions according to the paradigms of neurocomputing. 3. Systemic (psychosomatic) diseases appear to result from erroneous diagnosis due to the defects of the autodiagnostic system. The influence of puncture on biologically active points corrects these defects, providing a positive therapeutic effect. A theoretical model for the structure and functioning of the autodiagnostic system is discussed. It is shown that the structure of the model autodiagnostic system coincides with that of Rexede plates forming the gray substance of the spinal cord. The experimental data on Rexede plates and their connections with organs and corresponding biologically active points are discussed. A relationship between the concept of the autodiagnostic system and the basic principles of alternative eastern medicine is discussed. It is shown that the Chinese model of puncture therapy represents a verbal description of the topological features of the phase space of the mathematical model for the recognizing neuroprocessor.
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Terapia por Acupuntura , Rede Nervosa/fisiologia , Fenômenos Biofísicos , Biofísica , Humanos , Medicina Tradicional Chinesa , Modelos Biológicos , Redes Neurais de Computação , Yin-YangRESUMO
Novel explanation is proposed for the improvement of low quality seeds by pre-sowing treatment with factors of various nature (heat and sonic treatment, electrical field of corona discharge, laser irradiation). The increase in seed germination percentage is caused by slowing-down of seed water uptake as a result of closing the aquaporin water canals.
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Germinação/fisiologia , Sementes/fisiologia , Aquaporinas/metabolismo , Estimulação Elétrica , Germinação/efeitos dos fármacos , Germinação/efeitos da radiação , Temperatura Alta , Lasers , Galato de Propila/farmacologia , Sementes/efeitos dos fármacos , Sonicação , Água/metabolismoRESUMO
The problem of origination of capacity for goal self-setting is discussed. It was shown that the definition "goal" in living systems differs from the definition "target function" in physical problems concerned with nonliving systems. It was also shown that the main goal of the elements of a system is the storage of information. In biology, this goal is the extension of the principle of struggle for existence. Conditions were determined that the dynamic system describing the goal self-setting process must satisfy. It was shown that living systems meet these conditions. In inorganic nature, such systems may also arise but only as a result of long-term evolution, after which they become living.
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Teoria da Informação , Evolução Biológica , Modelos Teóricos , Origem da VidaRESUMO
The properties of the mixing layer in dynamic systems were studied by the example of a mathematical model of the cubic image type. Its role in the generation of information and the evolution of its significance was shown. At the moment of generation, information is of zero significance, and this significance then increases. A criterion of efficiency was proposed, and the optimum moment of making a decision in creative work was determined. It was shown that the increase in the variability of the parameters of a living system upon entry into the mixing layer and its decrease upon exit can serve as objective indicators of the transition of the system from one dynamic regime (attractor) to another.
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Teoria da Informação , Dinâmica não Linear , Algoritmos , Simulação por Computador , Teoria dos Jogos , Modelos Teóricos , Pisum sativum/fisiologia , Sementes/fisiologiaRESUMO
Kinetic electropuncture diagnosis (CASKED) is the advancement of Voll's method and is characterized by a basically new procedure to apply an electrical signal to the acupuncture points (AP). This method records and analyzes not only the amplitude of AP potential, but its temporal kinetics (in the range up to 100 seconds), he characteristic times of kinetic changes are used as diagnostic signs. CASKED makes it possible to make a direct diagnosis by taking into account the localization and characteristic features of a pathological process and to access changes in a patient's condition during treatment.
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Pontos de Acupuntura , Acupuntura/métodos , Biofísica , Diagnóstico , Eletrodiagnóstico , Algoritmos , Fenômenos Biofísicos , Humanos , Cinética , Modelos Teóricos , Fatores de TempoRESUMO
The photocycle kinetics of bacteriorhodopsin were analyzed from 0 to 40 degrees C at 101 wavelengths (330-730 nm). The data can be satisfactorily approximated by eight exponents. The slowest component (half-time 20 ms at 20 degrees C) belongs to the 13-cis cycle. The residual seven exponentials that are sufficient to describe the all-trans photocycle indicate that at least seven intermediates of the all-trans cycle must exist, although only five spectrally distinct species (K, L, M, N, and O) have been identified. These seven exponentials and their spectra at different temperatures provide the basis for the discussion of various kinetic schemes of the relaxation. The simplest model of irreversible sequential transitions includes after the first K--> L step the quasiequilibria of L<-->M, M<-->N, and N<-->O intermediates. These quasiequilibria are controlled by rate-limiting dynamics of the protein and/or proton transfer steps outside the chromophore region. Thus there exists an apparent kinetic paradox (i.e., why is the number of exponents of relaxation (at least seven) higher than the number of distinct spectral intermediates (only five)), which can be explained by assuming that some of the transitions correspond to changes in the quasiequilibria between spectrally distinct intermediates (i.e., are spectrally silent).
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Bacteriorodopsinas/química , Fotossíntese , Halobacterium/química , Cinética , Modelos Biológicos , Análise Espectral , TemperaturaRESUMO
Spatial coexistence and competition among species is investigated through a modified Volterra-Lotka model which takes into account sexual breeding. This allows the population specific growth rate to depend on the population density. As a result of this modification the degeneracy inherent in the classical model is eliminated and qualitatively novel regimes are observed, as demonstrated by parametric analysis of the model. In the case where the corresponding parameters of competing species do not differ significantly the model can be reduced to a single Ginzburg-Landau type equation. The spatially distributed model is analyzed both in the absence and in the presence of noise mimicking inherent fluctuations in birth and death rates. It is shown that noise can qualitatively change the behavior of the system. Not only does it induce the formation of spatial patterns, but also switches on endless turbulent-like rearrangement of the system. When initially unpopulated habitat is occupied by competing species even a very low-intensity noise makes the final state of the system totally unpredictable and sensitive to any fluctuations. (c) 1996 American Institute of Physics.
RESUMO
The temperature and pH dependencies of the O(640) intermediate of the photocycle of bacteriorhodopsin (bR) were investigated by flash photolysis and T-jump experiments. The maximal concentration of the O(640) intermediate was found to be dependent on the temperature, which is described by a sigmoidal relationship. With increasing pH the midpoint of the sigmoidal curves shifts to higher temperatures. The Van't Hoff equation provides enthalpy and entropy values of the observed states. These results indicate that, in the investigated temperature (0-60 degrees C) and pH (pH 4.0-10.0) range, the sequence of the principal intermediates in the pathway "M-N-O-bR" does not change. The observations of the O(640) intermediate at pH < 8.0 and of the N(550) intermediate at pH > 8.0 are most probably due only to changes of the intrinsic rate constants of the bR photocycle, not to a different mechanism.
RESUMO
The photoinduced electric response of oriented purple membranes associated with processes before the K-intermediate decay of bacteriorhodopsin was measured in the 180-300 K temperature range. These response signals consist of two kinetically distinct components (both temperature dependent). The experimental data show a correlation between the time constants of the rise of the signal and solution resistance. A model is proposed to assign these components to two diffusion-limited processes of charge displacement in the solution. The displacement is caused by the electric field of the photoinduced transient dipole which is formed in the primary act of the bacteriorhodopsin photocycle. The two processes are assigned as: (a) the conduction of electrical current through H-bonds (time resolved only in the temperature range 180-200 K) and (b) the diffusion of charges through the interfacial layer.
RESUMO
A model of the last parts of the bacteriorhodopsin (bR) photocycle is proposed on the basis of experimental data for the kinetic behavior of the 'O' intermediate during a temperature pulse in distilled water suspension. The model includes the previously proposed (but not well characterized) intermediate 'N' between the 'M' and 'O' states of bR. This intermediate exists in fast temperature-dependent quasi-stationary equilibrium with the red-shifted intermediate 'O' and has a maximum of absorption close to the bR spectrum.
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Bacteriorodopsinas , Cinética , Fotoquímica , Análise Espectral , TemperaturaRESUMO
Analysis is presented of the concept "protein-machine" and implying consequences, both of theoretical and experimental character. The approach "protein-machine" is compared with other approaches--"coherent excitation", "molecular dynamics" and "limited diffusion". In terms of the approach "protein-machine" valuable information inserted in the biological macromolecule and determining its functions is taken into account. It reflects the biological specificity and at the same time removes mystic shadow from this concept.
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Modelos Teóricos , Proteínas , Enzimas , Cinética , Conformação ProteicaRESUMO
Applications of synergetics to ontogenesis are discussed. In terms of synergetics, the choice between the concepts of power and parametric control and the description of parameters and dynamic variables of ontogenesis are among the main tasks of the theory of ontogenesis. Examples are provided for multipotency and variability which suggest the parametric control of development. A suggestion is put forward concerning the parameterizing role of directive inductors. Possible ways of overcoming the ambiguity inherent in the parametric control are considered. A general scheme of the ontogenesis control is proposed within the framework of which different types of parameters and dynamic variables are characterized. The concept of chaos is discussed with reference to ontogenesis.
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Envelhecimento , Crescimento , Modelos Biológicos , Animais , Comunicação Celular , Diferenciação Celular , Homeostase , HumanosRESUMO
A multicomponent reaction-diffusion system containing two different space scales (contrasting system) is considered. It is shown that if the system answers several conditions enumerated, it can be reduced to a bicomponent system which describes a dissipative structure either of a peak or of a step type. While in the first case the original and the final systems are equivalent only in the neighbourhood of zero, in the second case the equivalence is more general as the solution of these systems does not leave the region for which the procedure of reduction was developed.