Search PubMed⌕ Search

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.

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

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

Sudden infant death syndrome: a cybernetic etiology.

The brain's processes, by hypothesis, involve information processing by an extraordinarily complex, highly sophisticated, self-organizing cybernetic system embedded in the central nervous system. This cybernetic system generates itself in successive stages. Breathing is, by default, an autonomous function, but breath control is learned. If there is not a smooth transfer of function at the time when a successor system (one that enables autonomous breathing to be overridden by voluntary control) takes over, breathing may cease, without any overt cause being detectable, even with a thorough postmortem examination. If conditions are such that, at that point, the infant's body lacks the strength to resume breathing again under autonomic control, Sudden Infant Death Syndrome may result. The theory explains why infants are at greater risk if they sleep face down.

Brain↗
PubMed1985

Impact of a cybernetic system of feedback to physicians on inappropriate hospital use.

A cybernetic control program aimed at reducing inappropriate days of hospital stay for patients was implemented for all Medicare admissions at hospitals in four counties in Western Maryland. The findings of a study of the program are reported here. The objective of the study was to determine the relationship of the volume of the physician's hospitalized patients on both the existing levels of inappropriate hospital utilization and the physician's response to the cybernetic system. The findings indicated that: (a) existing levels of inappropriate hospital use generally increased with higher patient volume, (b) physicians with a low volume of hospitalized patients were less likely to decrease their inappropriate use of hospitals as a result of feedback than physicians with medium or high volumes of admitted patients, and (c) at all volume levels, the average decrease in inappropriate days was larger than the average increase in inappropriate days.

Cybernetics↗
PubMed2004

Fuzzy differential inclusions in atmospheric and medical cybernetics.

Uncertainty management in dynamical systems is receiving attention in artificial intelligence, particularly in the fields of qualitative and model based reasoning. Fuzzy dynamical systems occupy a very important position in the class of uncertain systems. It is well established that the fuzzy dynamical systems represented by a set of fuzzy differential inclusions (FDI) are very convenient tools for modeling and simulation of various uncertain systems. In this paper, we discuss about the mathematical modeling of two very complex natural phenomena by means of FDIs. One of them belongs to the atmospheric cybernetics (the term has been used in a broad sense) of the genesis of a cyclonic storm (cyclogenesis), and the other belongs to the bio-medical cybernetics of the evolution of tumor in a human body. Since a discussion of the former already appears in a previous paper by the first author, here, we present very briefly a theoretical formalism of cyclone formation. On the other hand, we treat the latter system more elaborately. We solve the FDIs with the help of an algorithm developed in this paper to numerically simulate the mathematical models. From the simulation results thus obtained, we have drawn a number of interesting conclusions, which have been verified, and this vindicates the validity of our models.

Algorithms↗
PubMed1990

Mind-body problems in family therapy: contrasting first- and second-order cybernetics approaches.

Using detailed case examples, we contrast first- and second-order cybernetics approaches to family problems involving somatic symptoms in a family member. A second-order cybernetics approach views the reality of the problem as linguistically shaped by those interacting around it, including the therapist and observing team members. This co-constructed reality, the story of the problem, inadvertently contributes to the problem's endurance by narrowing the choice of more effective solutions. In our approach, the therapist elicits from each person his or her story about the illness in the family. The therapist then facilitates a therapeutic conversation that provides a context for new linguistic distinctions to be drawn, including the way mind and body may interact to generate the symptoms. Shifts in beliefs and behaviors follow, and more innovative solutions to the problem can then emerge. Unlike the approach in our previously published work based upon ecosystemic patterns as "system diagnoses," this approach uses only descriptions and explanations of the problem as are collaboratively constructed within this therapeutic conversation.

Adult↗
PubMed1988

Cybernetics, activation, and drug effects.

Patients present unique combinations of familial relationships, developmental idiosyncrasies, social aberrations, affective states, cognitive abilities, symptoms, defects, and maladaptations. Psychopharmacological treatments form a useful approach to cutting through this complexity to the core pathophysiology. Focusing on disorders that can be brought to complete remission by medication suggests that retarded and agitated depressions, manic and angry hyperactive paranoid states, panic disorder, emotionally unstable character disorders and schizophrenias are governed by the degree of derangement of an affective-activation control system. Defects in this control system are best conceptualized in cybernetic terms rather than in terms of the current rheostat models. Conceptualization of cybernetic defects allows for understanding of psychopathological developments as well as give a framework for pharmacological benefits. One aspect of the activation-affective disorders, are disorders of two types of pleasure regulatory mechanism, here referred to as appetitive and consummatory. The relationship of disorders of these hedonic control mechanisms to affective states and those of drug abuse are considered. This schema also affirms a close relationship between the bipolar affective disorders and the schizophrenias.

Arousal↗
PubMed2006

Cybernetic principles in the systematic concept of hypothalamic feeding control.

Research on biological mechanisms of eating behavior and related disorders, such as obesity and anorexia nervosa, has become a large field of research in the last 15 years. With the discovery of peptides related to hypothalamic control of food intake (e.g. leptin and ghrelin) the search for the biological 'master key' of feeding control was renewed. As a result, mid-20th century biological concepts based on systematic and cybernetic thoughts fell into oblivion. This review highlights discoveries of hypothalamic-controlled feeding and eating behavior with a cybernetic and systematic perspective. Interestingly, older ideas of hypothalamic function offer possibilities for the incorporation of new molecular discoveries into systematic concepts of feeding behavior.

Animals↗
PubMed2001

Interaction with the environment: anthropological cybernetic model.

Cybernetics is primarily concerned with the transfer of information through, and (re)actions of systems. The research aim was to investigate models of interaction dynamics between an anthropological system and its environment. Equifinality dynamic model defined by three compartments and propensity for establishment of a steady state regardless of the initial conditions was applied. The intention was to apply this concept in anthropological research using the OPSIM procedure. DYNOPS model defined by four age-group compartments and the environment was also used. The model was applied on the census of the Bogomolje village on the island of Hvar (R. Croatia). Through numerous simulations, it was found that the influence of the environment increases with the decrease of time spent in the young age compartment. A drawback of DYNOPS model is that it places the environment in an unchangeable category, while in reality it necessarily changes through numerous interactions with various agents. Finally, cybernetics should not only be used to explicate, but also predict and correct undesired communal developments.

Adolescent↗
PubMed1984

[Role of medical cybernetics in the improvement of diagnosis, prognosis and choice of treatment method in pulmonological patients].

The authors review some aspects of the use of medical cybernetics methods in pulmonology. Analyze the results of machine and machine-free (mark) diagnosis of chronic lung diseases. Demonstrate that the quality of the disease recognition by means of the cybernetic methods correlates with that attained by highly specialized therapeutic institutions. Discuss the results of predicting the outcomes of the treatment of respiratory system diseases and the possibilities of using the mathematical methods for the classification optimization.

Cybernetics↗
PubMedDate not supplied

[Current aspects of the physiopathology of the infectious process. II. Cybernetic elements in the pathogenetic structure of infectious diseases].

The authors discuss the applicability of general cybernetic principles (the theory of systems and self-regulated mechanisms based on inversed connections) to the pathophysiologic structure of infections. With reference to concrete examples they outline the following elements: the appartenance of the infectious process to the notion of system (as conceived in the theory of systems), the previsible character of the functional potential of the structured system in the components of infection, and the sequental correspondence between system dynamics and the dynamics of the infectious process. Starting from the mechanism of action of the main microbial toxins, the aptitude of the latter to act upon the functional code of the macroorganism, altering the cellular and supracellular self-regulated biosystems, is demonstrated. Finally, the practical implications of assimilating cybernetic processes in the pathophysiology of infectious diseases are analyzed.

Bacterial Infections↗
PubMed1981

[Cybernetic analysis of the heart rhythm in the measured physical loading test with crew members of the Saliut-6 orbital station].

The authors report on the study of the members of four lengthy expeditions on the orbital station "Saliut-6" in the exercise test with the bicycle ergometer at the station. The cybernetic analysis of the cardiac rhythm during its adaptation to weightlessness shows the definite changes of the controlling systems of the body. It is shown that the "cost" od adaptation to exercise is determined by the results of the cybernetic analysis of the cardiac rhythm.

Adaptation, Physiological↗
PubMed1980

[Cybernetic conceptualization of the levels of hypnosis].

The synaptic function of the different associational levels of cortex and cortico-subcortical depending on inputs memorised in synchronism at each level, is probably responsible, on a broad scale of values, for auto- or heteroinducible levels of hypnosis due to inputs solicited by extraneuronal values determining feed-back with inputs recorded in neuronal DNA. This hypothesis is outlined here with reference to the same Author's "Metodica psicoterapica su elementi di cultura cibernetica" (Minerva Medica, 63, 968, 1972). Sophronic levels, and levels of hypnosis and hypnotism are, in the light of elements of cybernetic culture, neurophysiologically referrable not only to qualitatively different causes, and more specifically to the final cause triggering electrobiochemical reactions. They are, in other words, referrable to the electron and its dynamics, increasingly well known today to students of cybernetics.

Cybernetics↗
PubMedDate not supplied

Integrative cybernetic model of oxygen homeostasis.

The paper presents an integrative cybernetic model of the complex physiological process generically called "oxygen homeostasis". The model has been designed in such a manner as to enable a mathematical approach, in quantitative terms, to the various functions involved in the generation and uninterrupted functioning of the mentioned process. Those functions are: pulmonary and tissular respiratory function, blood circulation, transport, erythropoiesis, as well as other functions involved in the blood pH regulation at renal and hepatic level (the resorption of Na+ ions from the glomerular filtrate and the ammonio-genetic functions of the kidneys and, respectively, the glyco-genetic, ureo-genetic and metabolization functions of the liver). All of these functions have been assumed as regulated and controlled within a unitary cybernetic system, interpreted as an open, dynamic system. That system consists of seven multicompartment subsystems which are open and interconnected by means of exchange relations, biophysical and biochemical processes involved in the performance of the respective function. Special attention was given to the mathematical modelling of the exchange processes going on in the erythrocytic membrane as part of the transport function of the circulating blood. The mathematical description of the entire homeostatic system operation was done by means of a set of differential and algebraic equations. Some of those equations (those describing the continuity of several chemical species in a compartment of the circulatory system and those characterizing the state of thermodynamic balance of the blood subsystem within the respective compartment) enable one to determine the value of the state parameters at a given moment, as a function of the external and internal conditions and as a function of the intensity of processes specific to the subsystems considered. There are other equations (equations of regulation and control devices) that enable one to determine the variations in intensity of the processes mentioned that are necessary in order to restore the system to its "normal" state, in case of possible deregulations caused by disturbing factors.

Animals↗
PubMed1999

Cybernetic model of the growth dynamics of Saccharomyces cerevisiae in batch and continuous cultures.

Growth of Saccharomyces cerevisiae on glucose in aerobic batch culture follows the well-documented diauxic pattern of completely fermenting glucose to ethanol during the first exponential growth phase, followed by an intermediate lag phase and a second exponential growth phase consuming ethanol. In continuous cultures over a range of intermediate dilution rates, the yeast bioreactor exhibits sustained oscillations in all the measured concentrations, such as cell mass, glucose, ethanol, and dissolved oxygen, the amounts of intracellular storage carbohydrates, such as glycogen and trehalose, the fraction of budded cells as well as the culture pH. We present here a structured, unsegregated model for the yeast growth dynamics developed from the 'cybernetic' modeling framework, to simulate the dynamic competition between all the available metabolic pathways. This cybernetic model accurately predicts all the key experimentally observed aspects: (i) in batch cultures, duration of the intermediate lag phase, sequential production and consumption of ethanol, and the dynamics of the gaseous exchange rates of oxygen and carbon dioxide; and (ii) in continuous cultures, the spontaneous generation of oscillations as well as the variations in period and amplitude of oscillations when the dilution rate or agitatin rate are changed.

Models, Biological↗
PubMed2000

Are microbes intelligent beings?: An assessment of cybernetic modeling.

Microorganisms growing in a multi-substrate medium have different and varying preferences for the various components of the medium. The preferences depend on the operating conditions and the substrates may be utilized sequentially or simultaneously. Sometimes an organism may change its preferences among substrates and/or switch between sequential and simultaneous utilization. These aspects are difficult to describe through models based on chemical and physical laws alone. Cybernetic modeling ascribes to microorganisms the ability to perceive their environment (i.e. the growth medium) and make 'intelligent' choices regarding substrate utilization to maximize an objective, which is usually the growth rate. This article reviews the development of cybernetic modeling since it began in 1982. Different workers have suggested different perspectives of how microbes make optimal use of their resources. These are discussed and future directions for improvement are indicated.

Journal Article↗
PubMed1999

Anthropological cybernetic model of demographic structures in the Republic of Croatia.

Intentions of the present investigation were: a) to apply a cybernetic model in description of demography of the Republic of Croatia and b) to underline specificity of this type model application in anthrolpology based on definitions of systems theory as a reaction against reductionism. The cybernetic model is based on the idea that continuous processes of childbirth and ageing can be represented by compartment analysis. Compartment subpopulations were subjected to: a) the elimination by mortality and emigration described by constants Fi,0, and b) the enlargement by the immigration process described by constants F0,i. The consistency of the model is evaluated through the comparison between model data and census. The model prediction of the census and mortality for the period between 1953 to 1998 is fair enough (within +/- 2%). Application of this type of models provides a possibility that the anthropological fitness of regions could be quantified. The obtained data reveals that autoreproduction of the system and its fitness could be described by the chaos theory.

Adolescent↗
PubMed2000

Anthropological cybernetic model of demography of the island of Hvar.

Intentions of the present investigation were to apply a cybernetic model in description of demography on the island of Hvar for a time period from year 1800 till now. The basic idea of the model applied in this anthropological study (LOPI) is that the rate of reproduction is given by the non-linear controller: Y2/Te(1-(Y3/G)). Constant G represents an environmental carrying capacity of a community with respect to the cohort of older people (no longer a part of the pool of reproductive inhabitants; Y3) sharing limited survival resources. The proportional constant 1/Te connected with the pool of reproductive inhabitants (Y2) correspond to the reproduction maximum. The consistency of the model is evaluated through comparison between model data and census. The LOPI model describes incredibly well the demography of the island of Hvar from the year 1800 till 1940. After year 1950 there were more inhabitants on the island then the model would predict. This fact is connected with changes in the migration or also in the increased carrying capacity (G). On the basis LOPI model, population dynamic oscillates in its development. The example of the island of Hvar has proved that population reaches a maximal number of inhabitants every 200 years. The oscillation of population dynamics is influenced by the migration processes. The mere fact that oscillating population size is connected to population genetics and probably also to sociocultural factors suggests that a cybernetics demographic model can be a guide in the holistic anthropological approach.

Adult↗
PubMed1985

Analysis of the morphology and function of primary cilia in connective tissues: a cellular cybernetic probe?

More than 300 primary cilia have been identified electronmicroscopically in a variety of embryonic and mature connective tissue cells. To further define the enigmatic function of these cilia, we examined the interrelationships between the basal apparatus and cytoplasmic organelles and the ciliary shaft and the extracellular matrix. The basal diplosome was consistently associated with the secretory organelles including the maturing face of the Golgi complex, Golgi vacuoles and vesicles, the microtubular network, the plasma membrane, and coated pits and vesicles. Small vesicles and amorphous granules were also observed within the ciliary lumen and adjacent to the ciliary membrane. Microtubule-membrane bridges linked axonemal tubules to the ciliary membrane. The position, projection, and orientation of the axoneme were influenced by the structural organisation and mechanical properties of the matrix and frequently caused angulation of the ciliary shaft relative to the basal body. Located midway between the secretory apparatus and the extracellular matrix, primary cilia would appear ideally situated to mediate the necessary interaction between the cell and its surrounding environment prerequisite to the formation and maintenance of a functionally effective matrix. We propose that primary cilia in connective tissue cells could act as multifunctional, cellular cybernetic probes, receiving, transducing, and conducting a variety of extrinsic stimuli to the intracellular organelles responsible for effecting the appropriate homeostatic feedback response to changes in the extracellular micro-environment.

Animals↗