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A threshold model used in toxicology posits that anything above a certain dose of a toxin is dangerous, and anything below it safe. This model is usually applied to non-carcinogenic health hazards. Edward J. Calabrese and Linda A. Baldwin wrote: The threshold dose-response model is widely viewed as the most dominant model in toxicology. [6]
The linear no-threshold model (LNT) is a dose-response model used in radiation protection to estimate stochastic health effects such as radiation-induced cancer, genetic mutations and teratogenic effects on the human body due to exposure to ionizing radiation. The model assumes a linear relationship between dose and health effects, even for ...
The first artificial neuron was the Threshold Logic Unit (TLU), or Linear Threshold Unit, [21] first proposed by Warren McCulloch and Walter Pitts in 1943 in A logical calculus of the ideas immanent in nervous activity. The model was specifically targeted as a computational model of the "nerve net" in the brain. [22]
The model is sometimes referred to as the Rating Scale Model when (i) items have the same number of thresholds and (ii) in turn, the difference between any given threshold location and the mean of the threshold locations is equal or uniform across items. This is, however, a potentially misleading name for the model because it is far more ...
SETAR models were introduced by Howell Tong in 1977 and more fully developed in the seminal paper (Tong and Lim, 1980). They can be thought of in terms of extension of autoregressive models, allowing for changes in the model parameters according to the value of weakly exogenous threshold variable z t, assumed to be past values of y, e.g. y t-d, where d is the delay parameter, triggering the ...
For example, the size distribution (number of clusters of size s) drops off as a power-law for large s at the threshold, n s (p c) ~ s −τ, where τ is a dimension-dependent percolation critical exponents. For an infinite system, the critical threshold corresponds to the first point (as p increases) where the size of the clusters become infinite.
Polygyny threshold model graph. The polygyny threshold model is an evolutionary explanation of polygyny, the mating of one male of a species with more than one female. The model shows how females may gain a higher level of biological fitness by mating with a male who already has a mate. The female makes this choice despite other surrounding ...
These results suggest that low dose levels of ionizing radiation may not increase cancer risk directly proportional to dose and thus contradict the linear-no-threshold standard model. [50] Mina Bissell , a world-renowned breast-cancer researcher and collaborator in this study stated: "Our data show that at lower doses of ionizing radiation, DNA ...