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D Tal

Publications and source records attributed to D Tal.

6 recordsLinked to original sources
PubMed2001

Frequency tuning of input-output relation in a rat cortical neuron in-vitro.

The input-output relation of a single neuron stands at the basis of every biologically oriented description of the brain. This report shows that the input-output relation of cultured cortical neurons is non-linearly tuned by the input frequency. Increasing the rate of stimulation results in the appearance of ordered temporal firing patterns, which are qualitatively different for different input frequencies. The experimental results of this study lead to the conclusion that frequency tuning of neuronal input-output relation arises from activity-dependent rates at the molecular level underlying the mechanism of excitability itself.

Action Potentials↗
PubMed1998

Management of acute gastroenteritis in children in Israel.

OBJECTIVE: Diarrheal diseases are a major cause of morbidity and mortality worldwide. Guidelines about the use of oral rehydration solutions (ORS) and dietary management of acute gastroenteritis (GE) were recently revised and published by the American Academy of Pediatrics (AAP). Study aims were to examine Israeli pediatricians' knowledge and implementation of the revised AAP guidelines, the effect of medical school (Israeli versus foreign medical graduates) on the physicians' practice, and the effect of the type of practice (community vs hospital-based) on the management of gastroenteritis. METHODS: A multiple-choice, written questionnaire was distributed at two pediatrics annual meetings. RESULTS: A total of 87 pediatricians completed the questionnaire. They were aware of 73% of the current AAP guidelines and followed 60% of the guidelines. Most pediatricians (83%) use ORS for treatment of dehydration in GE, but 60% of pediatricians believe that full-strength feeds are inappropriate in the presence of GE, and 67% of them do not recommend full-strength formulas. In addition, 37% of the pediatricians stop feeding temporarily in the presence of GE, in contrast to the 1996 AAP guidelines. There were no differences in knowledge and management practices among pediatricians graduating in Israel, Europe, or the United States, and no differences between pediatricians working in an ambulatory setting or in a hospital. CONCLUSIONS: Pediatricians in Israel, regardless of country of origin, medical school, or place of practice, are aware of the correct use of ORS but do not follow nutritional practices recommended recently by the AAP. These findings suggest that steps for implementing the guidelines are needed in Israel and most probably worldwide.

Acute Disease↗
PubMed1997

Computing with the leaky integrate-and-fire neuron: logarithmic computation and multiplication.

The leaky integrate-and-fire (LIF) model of neuronal spiking (Stein 1967) provides an analytically tractable formalism of neuronal firing rate in terms of a neuron's membrane time constant, threshold, and refractory period. LIF neurons have mainly been used to model physiologically realistic spike trains, but little application of the LIF model appears to have been made in explicitly computational contexts. In this article, we show that the transfer function of a LIF neuron provides, over a wide-parameter range, a compressive nonlinearity sufficiently close to that of the logarithm so that LIF neurons can be used to multiply neural signals by mere addition of their outputs yielding the logarithm of the product. A simulation of the LIF multiplier shows that under a wide choice of parameters, a LIF neuron can log-multiply its inputs to within a 5% relative error.

Action Potentials↗
PubMed1992

Personal determinants of leisure-time exercise activities.

This study investigated the importance of personal determinants such as self-efficacy, beliefs about the contribution of exercise, health locus of control, and dispositional optimism for leisure-time exercise in a working population. The main predictors of such exercise were beliefs and self-efficacy with the generalization of the latter to eat correctly. Beliefs and efficacy expectations were highly correlated. Neither health locus of control nor dispositional optimism was related to leisure-time exercise; however, optimism was related to the positive belief that exercise contributes to health. Ramifications of the findings were carefully described.

Adolescent↗
PubMed1986

3'-O-(4-benzoyl)benzoylcytidine 5'-triphosphate. A substrate and photoaffinity label for CMP-N-acetylneuraminic acid synthetase.

A photoreactive, radiolabeled pyrimidine nucleotide, 3'-O-(4-benzoyl)benzoylcytidine 5'-triphosphate was synthesized from benzoylbenzoic acid and radiolabeled CTP. Benzoylbenzoyl-[5-3H]CTP could substitute for CTP, in an enzymatic reaction with N-acetylneuraminic acid catalyzed by Escherichia coli or rat liver CMP-NeuAc synthetase, to yield radiolabeled benzoyl-benzoyl-CMP-NeuAc. E. coli CMP-NeuAc synthetase could be specifically radiolabeled using benzoylbenzoyl-[alpha-32P]CTP as a photoaffinity label. This specific covalent binding occurred using enzyme preparations of different degrees of purity. These results suggest that benzoylbenzoic acid derivatives of pyrimidines should be of general use in the identification and active site mapping of pyrimidine-requiring proteins and enzymes. These include glycosyltransferases, sugar nucleotide synthetases, and transporters, and enzymes participating in the conjugation of bile acids and biosynthesis of nucleic acids and choline nucleotides.

Affinity Labels↗