Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Probability Theory”

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 901 records · Page 50Linked to original sources
PubMed1985

The repair-misrepair model in radiobiology: comparison to other models.

Biological phenomena related to the inactivation of eukaryotic cells by noxious agents have been formulated mathematically in the repair-misrepair (RMR) model by separately quantitating the initial submicroscopic production of molecular lesions and the later, macroscopic expression of effects in the course of cell progression and repair. This paper presents some conceptual and quantitative similarities and differences between the RMR and seven other models proposed for cellular radiobiology including: the linear-quadratic, three-lambda, cubic-survival, target theory, hit-size probability, cybernetic, and lethal-potentially lethal models. The comparison of the various approaches has shown that the RMR model can be generalized to show relationships with each.

Animals↗
PubMed1983

On structure formation and the processes of alteration.

What have traditionally been called the mechanisms of defence are processes which also have the function of contributing to the development of psychic structure. Some of these processes of ego alteration are re-examined with regard to their origin and manner of functioning. Primal repression is inextricably tied up with the development of the secondary processes, while the processes of introjection and identification contribute to the building up of the structure of the ego-ideal-superego complex and the ego respectively. Projection and reaction formation function as defences through the hypercathexis of existing ego processes or structures as probably does disavowal as well. Undoing is better regarded not as a defence mechanism or process of alteration but as the manifestation of an ego split following the failure of reaction formation. The concept of hypercathexis involves problems in the nature of psychic energy, a concept which in some form or other is probably indispensable to psychoanalytic theory.

Cathexis↗
PubMedDate not supplied

[Analysis of the informational and activating components of reinforcement in a conditioned reflex experiment].

The reinforcement in adaptive behaviour performs at least two functions: satisfaction of specific need (activational component) and estimation of signal significance of the conditioned stimulus while comparing the nervous model of the stimulus with current afferentation (informational component). In usual conditioning experiments with permanent reinforcement these components concide and therefore do not differ. However, they may be separated in the case of probabilistic reinforcement by changing stimuli contingency and shifting motivational level. With this aim the diagrams of probabilistic stimuli and reactions space, semantic and pragmatic matrices are worked out, allowing to estimate correlations of these parameters of conditioning experiments. Comparative psychophysiological investigations showed the possibility of determination of species peculiarities in behavioural choice strategies among various animals under above mentioned conditions.

Adaptation, Physiological↗
PubMed1996

Predicting unpredictability: a model of women's processes of predicting battering men's violence.

This paper proposes a theoretical model of how women predict men's violence within the context of battering. The model was developed from a grounded theory study of 30 women. Participants were recruited using advertisements in free neighborhood newspapers. Interviews were conducted in small groups or individually. The analysis revealed that battered women developed sophisticated knowledge about and response patterns to their partners' violent behaviors. They identified specific changes in their partners' eyes, speech, and tone of voice and described specific situations that served as warning signs of potential violence. Once able to identify warning signs, women responded with strategies of avoidance, engagement, fleeing, and enlisting the help of others to avert or delay violent incidences. These strategies provided temporary relief but did not usually result in the cessation of violence.

Adult↗
PubMed1997

Bayesian design for dose-response curves with penalized risk.

This paper considers some Bayesian design problems in quantal response analysis. An experimenter must choose a set of dose levels and number of independent observations to take at these levels, subject to a total sample size, in order to estimate some characteristic phi, e.g., ED50, of a tolerance distribution F theta, where theta is the vector of unknown parameters. It is shown for the logistic model that the sampling variability of the posterior variance of phi is such that the predicted posterior variance alone is an undesirable criterion for design selection. A family of penalty functions is introduced that penalizes any excess in the posterior variance over the expected or predicted variance and protects against unexpected outcomes. The goal is to find a design that avoids experimental results with little information, at the expense of a small sacrifice in the Bayes risk. Numerical results indicate that the chance of an extreme posterior variance can be reduced by sacrificing a small amount of posterior risk.

Animals↗