SEARCH · PubMed Health

Results for “LOGIC”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 19 recordsLinked to original sources

PubMed2003

A biochemical logic gate using an enzyme and its inhibitor. Part II: The logic gate.

Enzyme-Based Logic Gates (ENLOGs) are key components in bio-molecular systems for information processing. This report and the previous one in this series address the characterization of two bio-molecular switching elements, namely the alpha-chymotrypsin (alphaCT) derivative p-phenylazobenzoyl-alpha-chymotrypsin (PABalphaCT) and its inhibitor (proflavine), as well as their assembly into a logic gate. The experimental output of the proposed system is expressed in terms of enzymic activity and this was translated into logic output (i.e. "1" or "0") relative to a predetermined threshold value. We have found that an univalent link exists between the dominant isomers of PABalphaCT (cis or trans), the dominant form of either acridine (proflavine) or acridan and the logic output of the system. Thus, of all possible combinations, only the trans-PABalphaCT and the acridan lead to an enzymic activity that can be defined as logic output "1". The system operates under the rules of Boolean algebra and performs as an "AND" logic gate.

Biosensing Techniques↗

PubMed1997

Self-organized marginal stability resulting from inconsistency between fuzzy logic and deterministic logic: an application to biological systems.

Complex systems in which internal agents (observers) interact with each other with finite velocity of information propagation cannot be described with a single consistent logic. We have proposed the bootstrapping system of cellular automata for describing such complex systems using two types of complementary logic: Boolean and non-Boolean. We extend this in this paper to a system of time-discrete continuous maps using fuzzy logic in place of non-Boolean logic. Fuzziness implies the intrinsic ambiguity of internal measurement. The bootstrapping system evolves, changing the dynamics perpetually, so that the discrepancy between the two types of complementary logic may be minimized. The equilibration force defined from the strength of discrepancy forms a landscape for self-organization which is similar to the fitness landscape for evolution. Though they appear similar, the former is derived from the internal dynamics. The goal of evolution, when applied to the map of the Belousov-Zabochinsky reaction, is demonstrated to be near the border between periodicity and chaos. The behavior depends on the degree of fuzziness and the extent of noise. When fuzziness increases too much, the system becomes unstable. Near the boundary, it exhibits intermittent chaos with a background of 1/f noise.

Animals↗

PubMed2000

Development of logical reasoning: children's ability to verbally explain the nature of the distinction between logical and nonlogical forms of argument.

Previous research by D. Moshman and B. Franks (1986) supported the hypothesis that children do not explicitly understand the nature of the distinction between logical and nonlogical forms of argument. This research examined the performance of 8-11-year-olds (N = 220) on Moshman and Franks's experimental tasks when the children were cued to apply particular comprehension strategies. Findings from 2 experiments indicated that a significant number of children are capable of explicitly recognizing the necessity of logical forms and the indeterminacy of nonlogical forms and that this competence must be distinguished from their tendency to fail to attend to structural relationships between propositions and to monitor the intrusion of extraneous personal knowledge in assessing the validity of an argument. The findings suggest that all of these competencies are important components of the ability to distinguish logical and nonlogical arguments.

Age Factors↗

PubMed1988

Matte Blanco and skelton: systems of logic and logic of systems.

In the light of recent debate regarding the conceptual integrity of Matte Blanco's bi-logical account of the unconscious, a related issue arises concerning how the logical systems are organized. The present article suggests one means by which this may be achieved while still retaining the heuristic value of Matte Blanco's systems.

Humans↗

PubMed2003

Analysis and evaluations of logical instructions called in parallel digital optical operations based on optical array logic.

The authors have analysed and evaluated a two-dimensional instruction set of parallel operation based on optical array logic (OAL), which is a digital optical computing paradigm, to clarify efficient composition of an optical computing system based on OAL. To evaluate parallel operation based on OAL, the author have introduced new indices and evaluated a logical instruction set of various parallel operations with the indices, so that a guideline for composing a simple and efficient OAL computing system is clarified. Also, the authors have proposed the reduced operation kernel set correlation technique to perform parallel operations more efficiently by a simple OAL computing system. It has been clarified that the technique can reduce the required hardware necessary for an OAL computing system for efficient general-purpose processing.

Journal Article↗

PubMed2002

Processing of logically valid and logically invalid conditional inferences in discourse comprehension.

Two competing theories of processing of conditionals (if-then) were tested. Syntactic theories posit that people only draw inferences conforming to the logically valid modus ponens (MP) schema. Mental models theories predict that people draw MP and invalid affirming-the-consequent (AC) inferences. Three experiments tested these predictions. Participants read short stories that conformed to either the MP or AC form but without conclusions, and they completed either priming or recognition tasks. Results indicate that both MP and AC inferences occur during discourse processing: MP and AC premise forms prime their respective conclusions, participants erroneously judged that they had read the conclusions to MP and AC arguments, and AC inferences did not stem from a biconditional interpretation of conditionals. Findings support mental models theories.

Adult↗

PubMed1994

The logic in ecological: I. The logic of analysis.

This paper addresses ecological studies in public health research in terms of the logic of their analysis. It makes several distinctions between studies based on ecological and individual units. First, it identifies the variables common to both types of study and those particular to ecological studies. Second, it shows how ecological and individual units combine in two classes: unmixed (purely ecological, purely individual) and mixed. Third, it details how the relationships among and between individual and grouped units (expressed in terms of regression coefficients between independent and dependent variables) yield four coefficients: for all individual members; for all groups; for all individuals within each group; and for all individuals within groups (a weighted average). Equipped with an understanding of the dimensions involved at ecological and individual levels and of the relationships between them, researchers are in a position to exploit the public health potential of the ecological approach.

Ecology↗

PubMed1994

The logic in ecological: II. The logic of design.

The utility of ecological studies is considered in terms of the salience of their designs and is exemplified in four levels: obligate and apt; optional and apt; optional, not apt but convenient; and maladroit (neither obligate, apt, nor justifiable by convenience). Ecological studies are obligate when they are the only choice available, either because of the question asked (as in testing differences between groups and discovering group effects), or where there are "dependent happenings" (as in transactions involving more than one individual), or because individual data are lacking. Apt studies are logically appropriate; analysis and results are not extrapolated beyond necessity or without precautions. Obligate studies enforced by lack of individual data may be apt or less than apt. Optional ecological studies may be apt or, if less than apt, they may yet be convenient. Maladroit studies are neither obligate, apt, nor convenient. Each class of study is illustrated by examples ordered according to a standard design hierarchy.

Ecology↗

PubMed1961