SEARCH · Search PubMed

Results for “CYBERNETICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources

PubMed1975

[Hypnosis: logic and cybernetics].

Fundamental notions concerning cybernetics, as derived from the systematic application of logic to questions of communication and control, are illustrated. Particular attention is given to the concepts of "system" "structure" and "dynamics" and it is shown that these concepts ensure that better and more exact understanding and forecasting of reactions in organised beings can be obtained. Turing to hypnosis, it is made clear that a trance is the execution of a momentarily proposed programme; it is not the result of a generalised mechanical action, but is preordained and geared to various situations. The difficulty that the hypnotised subject finds in aciting against his own interests, or against moral priniciples, can be seen, for example, as a consequence of pre-programming. Another result is given moment and a given type of person. Since cybernetis has proved useful in psychology, the hope is expressed that it can be included as a teaching subject for those who learn, practise and teach hypnotism.

Cybernetics↗

PubMedDate not supplied

[A systemic-cybernetic approach to the treatment of psychosis and depression].

An epistemological frame of references wherein activities performed at Servicios de Salud Mental (Mental Health Wards) of La Matanza District (Province of Buenos Aires, Argentina) is discussed. Such frame is systemic-cybernetically oriented, assuming that a therapeut's function deals with triggering a feedback process order so that any disrupted ecology is likely to become self-correctable. It is the author's contention that studies should deepen on how individuals, families--or the system--could be in a position to make their own adjustments. In other words, how could they heal themselves.

Argentina↗

PubMed1990

Neurobiological mechanisms of adaptative plasticity. A possible contribution to cybernetic studies.

Cybernetics can take advantages of future development in the field of Plasticity. The adaptative abilities of the nervous tissue, which is capable to modify its own functional organization and cope with pathological events, are triggered by communication within a network carrying memorized variations in the functional activity of the system induced by external inputs. Plasticity is served by anatomical modifications, as well as by neurophysiological processes. Regeneration, reactive synaptogenesis, functional reorganization, redundancy, equipotentiality are discussed. Some of these mechanisms are still unclear in the human and probably far-fetched. Personal EEG contribution argues against redundancy and equipotentiality.

Animals↗

PubMed1994

Cybernetic hypothesis of periodontal disease in mammalian carnivores.

Factors known to govern the pathogenesis of periodontal disease of carnivores are reinterpreted from an ecological perspective. A cybernetic hypothesis is generated which predicts and explains population control mechanisms. Sensitivity to prevailing conditions and the ability to exert a powerful influence upon those conditions is central to the hypothesis. Natural and domestic situations are contrasted with demonstration of a range of immune-mediated conditions arising from a permanent septic focus in the mouths of domestic cats and dogs. The hypothesis is expected to withstand critical scrutiny. In which case a new theory at the heart of a new paradigm will set the future course.

Animal Feed↗

PubMedDate not supplied

Conflicts of thermal adaptation and fever--a cybernetic approach based on physiological experiments.

Cold adaptation aims primarily at a better economy, i.e., preservation of energy often at the cost of a lower mean body temperature during cold stress, whereas heat adaptation whether achieved by exposure to a hot environment or by endogenous heat produced by muscle exercise, often brings about a higher efficiency of control, i.e., a lower mean body temperature during heat stress, at the cost of a higher water loss. While cold adaptation is beneficial in a cold environment, it may constitute a detrimental factor for exposure to a hot environment, mainly because of morphological adaptation. Heat adaptation may be maladaptive for cold exposure, mainly because of functional adaptation. Heat adaptation clearly is best suited to avoid higher body temperatures in fever, no matter which environmental conditions prevail. On the other hand, cold adaptation is detrimental for coping with fever in hot environment. Yet, in the cold, preceding cold adaptation may, because of reduced metabolic heat production, result in lower febrile increase of body temperature. Apparently controversial effects and results may be analyzed in the framework of a cybernetic approach to the main mechanisms of thermal adaptation and fever. Morphological adaptations alter the properties of the heat transfer characteristics of the body ("passive system"), whereas functional adaptation and fever concern the subsystems of control, namely sensors, integrative centers and effectors. In a closed control-loop the two types of adaptation have totally different consequences. It is shown that the experimental results are consistent with the predictions of such an approach.

Acclimatization↗

PubMed2003

Effect of fluid dispersion on cybernetic control of microbial growth on substitutable substrates.

Many fermentation media contain two or more substrates, which a microorganism utilizes for similar purposes. Depending on the conditions prior to and during a fermentation, the substrates may be utilized in succession or simultaneously. Since it is difficult to portray this behavior through mechanistic models, a cybernetic method was proposed earlier. Here the microorganism chooses the mode of substrate utilization that maximizes its own survival, usually expressed by the growth rate. In a fully dispersed bioreactor, simultaneous utilization generates higher growth rates but leads to low biomass concentrations since this utilization pattern is preferred at low concentrations of the substrates. In this study it has been shown that by allowing less than complete dispersion in the broth it is possible to shift from sequential to simultaneous utilization at high concentrations, thereby enabling both high growth rates and large biomass concentrations. This strategy thus allows the natural incomplete dispersion in large bioreactors to be gainfully exploited.

Journal Article↗

PubMed1999

Cybernetic modeling of spontaneous oscillations in continuous cultures of Saccharomyces cerevisiae.

We have developed a 'cybernetic' model to simulate the dynamic competition between all the available metabolic pathways of yeast Saccharomyces cerevisiae. This computer model predicts all the key experimentally observed aspects of the sustained oscillations in all the measured concentrations in continuous cultures, such as the spontaneous generation of oscillations as well as the variations in period and amplitude of oscillations when the dilution rate or agitation rate are changed.

Computer Simulation↗

PubMed2002

Quantitative modelling of crude oil toxicity using the approach of cybernetics and structured mechanisms of microbial processes.

Cybernetics and structured approach to biochemical processes in microbial cells offer the status of using various cell components of Azotobacter as molecular markers in toxicity assay of environmental toxicants. The intra-linked dynamic physicochemical reactions of the basic macromolecules--DNA, protein and membrane lipids--with respect to the crude oil in the growth environment, results in an 'impulse transfer function'. The structured effects are reduction in both DNA and protein levels, and an elevated level of lipid peroxidation products. Toxicity index (Ti) of the crude oil, at a given concentration, is the percent ratio of the summation of the products of these effect parameters' and their respective weightings, relative to control. The EC50 is the effective percent (w/v) concentration of the crude oil at which a toxicity index of 50% was recorded, and this corresponded with about 44% loss in nitrogen fixation of the diazotrophic bacterium.

Azotobacter↗

PubMed2003

Cybernetic modeling of the cephalosporin C fermentation process by Cephalosporium acremonium.

A cybernetic mathematical model has been developed to describe the production of cephalosporin C. In developing the model, diauxic behavior of substrate consumption, morphological differentiation of cells, and catabolite repression of cephalosporin C production by the preferred substrate, glucose, were considered. The proposed model was tested on the experimental data from the literature and could adequately describe the morphological differentiation of cells, the sequential utilization of carbon sources and the production of cephalosporin C. It could be a useful tool to optimize the production of cephalosporin C by Cephalosporium acremonium in batch, fed-batch or continuous operations.

Acremonium↗

PubMed1986

The QT-sensitive cybernetic pacemaker: a new role for an old parameter?

A critical review of the available data on QT interval is presented to delineate techniques useful to the development of a QT-sensitive cybernetic pacemaker. The reason for the development of this unit stems from the ability of QT prolongation to predict the onset of life-threatening ventricular arrhythmias in some clinical situations; the QT interval is physiologically related to the cardiac cycle length, therefore providing adequate information to drive both ventricular and atrioventricular sequential rate-responsive pacemakers. This unit might also monitor cardiac rhythm and detect the pathophysiologic precursors of advanced grades of ventricular arrhythmias. A therapeutic role, both pharmacologic and electrical, may also be possible in the future. Integration of these concepts and cooperation between interested physicians, technicians and manufactors will be necessary to produce such a unit at a low cost-benefit ratio. The potential clinical application of this pacemaker deserves attention for the prophylaxis and treatment of sudden arrhythmic death.

Arrhythmias, Cardiac↗

PubMed1962