Here we study further the multivariate quasi-interpolation of sigmoidal and hyperbolic tangent types neural network operators of one hidden layer. We derive multivariate Voronovskaya type asymptotic expansions for the error of approximation of these operators to the unit operator. RESUMEN Aquí estudiamos extensiones de la cuasi-interpolación multivariada de operadores de redes neuronales de tip...

ATP and ADP inactivate rabbit liver fructose 1,6-diphosphatase and change the nature of inhibition by AMP from sigmoidal to hyperbolic, with a concomitant increase in sensitivity to the inhibitor. 3-Phosphoglycerate both prevents and reverses the inactivation and restores the sigmoidal inhibition characteristics. The above kinetic behavior, which was observed with physiological concentrations o...

Parameter identification in a 2-node network with sigmoidal activation functions is considered. Given the nonlinearity in the weights, standard estimation algorithms based on linear parametrization are inadequate tools for studying global parameter convergence. In this paper, we provide an alternative approach for studying parameter identification in the presence of sigmoidal parametrization. C...

Pharmacokinetic/pharmacodynamic (PK/PD) relationships describe the quantitative relationships between the drug-induced effects and the concurrent corresponding drug concentrations in an individual. Since a long time, rough qualitative relationships have been described between neurological presentation and plasma ethanol concentration in acute ethanol ingestion. However, to date, precise quantit...

The photopigment in the human eye that transduces light for circadian and neuroendocrine regulation, is unknown. The aim of this study was to establish an action spectrum for light-induced melatonin suppression that could help elucidate the ocular photoreceptor system for regulating the human pineal gland. Subjects (37 females, 35 males, mean age of 24.5 +/- 0.3 years) were healthy and had norm...

This study examined the suitability of sigmoidal (SIG) and exponential (EXP) functions for modeling HR kinetics at the onset of a 5-min low-intensity cycling ergometer exercise test (5MT). The effects of training status, absolute and relative workloads, and high versus low workloads on the accuracy and reliability of these functions were also examined. Untrained participants (UTabs; n = 13) per...

We prove that feedforward artificial neural networks with a single hidden layer and an ideal sigmoidal response function cannot provide localized approximation in a Euclidean space of dimension higher than one. We also show that networks with two hidden layers can be designed to provide localized approximation. Since wavelet bases are most effective for local approximation, we give a discussion...

Phagocytosis of microspheres in V79 Chinese hamster lung cells was investigated by flow cytometry. Fluorescent microspheres (1.8 micron diameter) were used as the ingesta. Change in the number of V79 cells containing fluorescent microspheres was measured as an index of phagocytic activity. With time there was a sigmoidal increase in cells containing microspheres. The phagocytosis of microsphere...