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Biomedical subjects

F E Yates

Publications and source records attributed to F E Yates.

At least 37 records · Page 2Linked to original sources
PubMed1980

Physical causality and brain theories.

The history of deterministic theories in physics is reviewed, and four levels of determinism are found: 1) absolute, 2) asymptotic, 3) probabilistic, and 4) absolute indeterminism. Nagel's view that all causal laws are deterministic in the frame of the state descriptions to which they refer is acknowledged, but the inevitability of macroscopic measurement noise may hint that dynamical laws are innately noisy. Quantum mechanical effects are not the noise source. Symmetry and broken symmetry are introduced as physical concepts that can account both for lawfulness, and for the hierarchical nature of the universe. Physical ideas are chosen over those of formal systems with indirect self-reference as the basis of a global theory of brains. By exclusion it is concluded that only a statistical thermodynamics, combined with nonlinear mechanics, has the features needed for theorizing about brains in a physical sense. Quantum mechanics is judged not to be relevant. New statistical thermodynamic theories are briefly described, and their strengths and weaknesses noted. The question, "Why should neuroscience look to physics for its theories?" is raised and answered. Some concrete objectives for a program of theoretical research are stated.

Brain↗
PubMed1977

Patterns of plasma free fatty acid concentrations in fasted, resting dogs.

Free fatty acid (FFA) concentrations were determined in arterial plasma samples obtained during short or prolonged fasts from resting, conscious adult male mongrel dogs. Arterial blood was continuously collected during experiments ranging from 2.25 to 15 h, from dogs fasted 1 or 5 days. Each continuous collection stream was divided at 45 equal intervals into separate sequential samples. In 18 experiments, no consistent pattern was found in plasma FFA concentrations: the concentrations were never constant, and fluctuations were only rarely periodic. Large, spontaneous, seemingly random level changes with amplitudes of 200-600 mueq/liter were observed in 14 experiments, that took from 1 to 8 h to complete. There was no apparent relation between these fluctuations and time of day or rectal temperature, and glucose concentrations remained unchanged during the FFA fluctuations. The inconstancy of plasma FFA levels and the irregularity of their fluctuations suggests that FFA production rates may be unregulated or only loosely regulated within a wide regulation band during the first few days of starvation. No current model of FFA metabolism preducts the observed patterns of FFA levels.

Animals↗