Showing papers in "Journal of Theoretical Biology in 1968"

TL;DR: A theory is proposed for the development of filamentous organisms, based on the assumptions that the filaments are composed of cells which undergo changes of state under inputs they receive from their neighbors, and the cells produce outputs as determined by their state and the input they receive.

TL;DR: The treatment is extended to cases where inputs are received by each cell from both directions along the filament, and the change of state and the output of a cell is determined by its presentState and the two inputs it receives.

TL;DR: Three different but related comprehensive statistical analyses of amino acid sequences in proteins are described, to search for evidence of significant sequence structure in individual proteins relative to a purely random arrangement of the amino acid residues and to attempt to relate any significant structure uncovered to the secondary and/or tertiary configuration of the protein.

TL;DR: Repression of mRNA synthesis is discussed for situations in which the repressor is either the protein encoded by the mRNA or a metabolite formed under the catalytic control of that protein.

TL;DR: An equation is proposed that may often be used to relate the intensity of a pharmacologic response to the concentration of drug in the body fluids of the intact animal or man.

TL;DR: Action potentials are constructed step by step in bimolecular lipid membranes by adjusting the membrane composition, ionic gradients, pH, temperature and the concentration of two proteinaceous adsorbates and generally conform to the Hodgkin and Huxley theory for action potentials in nerve.

TL;DR: It was stressed that, when the first peak of the wave is below 80% (or the second below 50%), coincidence of the experimental curve with the theoretical one obtained, by putting presumed estimates into the parameters, should be reached by trial and error before the estimates are finally trusted.

TL;DR: For suspension of randomly oriented, asymmetric particles of slightly irregular shape, reasonably accurate estimates of the light scattering can be computed from simple Rayleigh-Gans theory, even when applied to large objects such as mammalian mitochondria or the most-studied bacteria, Escherichia coli.

TL;DR: It was found that slight non-segregative association occurred generally and evidence of segregative association was obtained from only three of the 13 bracket collections examined, which is generally useful in interpreting data from such populations.

TL;DR: It is shown that in principle a stable balance can be achieved between the attractive force and the repulsive force for hexagonally-packed, charged cylinders in the ionic solution.

TL;DR: Assuming an S-shaped population or organism size versus time curve and a growth rate law, the rate equation can be converted to an integral function from which the best pair to describe the growth rate can be obtained graphically.

TL;DR: A two-population variant of the program is described and is used to simulate some simple types of competition and predator-prey interaction, and the effects of varying fecundity, and introducing a time-lag are examined.

TL;DR: A new method is proposed for determining the effects of internal particle structure on observable light fluxes and it is found that when a particle becomes less homogeneous, large angle scattering should increase and small angle scatteringShould decrease.

TL;DR: The results show that at low electrolyte concentrations the electrical double layer should cause a decrease in the membrane capacitance, but for surface charge densities commonly encountered in practice the capacitance is predicted to be much less sensitive to electrolyte concentration such that it may not decrease appreciably even at 10 −6 mole/1.

TL;DR: Three models concerning the adaptive growth of bone in response to stress are considered from the point of view of the minimum amount of information required by any local group of cells, showing that a model produced by Bassett will not work unless the bones are considered as solid.

TL;DR: The asymptotic dependence of trapping time on N, the number of sites per trap, found to be proportional to N ln N by Pearlstein (1966) and by Robinson (1967) in square networks, has been verified and extended to the triangular case.

TL;DR: The author advances the thesis that sucrose acts as a protected derivative of glucose, and various properties of the sucrose molecule enhance its suitability for such a role as a translocate of higher plants.

TL;DR: It is pointed out that the results of Barrett (1966) apply only to a population in which the expected number of cells remains constant, although for practical purposes it appears that this restriction affects the PLM-curve only slightly.

TL;DR: The application of information analysis to phytosociology is rapidly gaining momentum, particularly in the field of diversity studies and, to a lesser extent, in descriptive, hierarchical, classifications.

TL;DR: It is suggested that cellular differentiation and oncogenesis are processes involving alterations in the absolute and relative values of the dynamic parameters governing the periodicities and hence changes in the pattern of cellular rhythms.

TL;DR: To explain the exceptional rate of amylase catalysis, a reaction mechanism involving a combination of general acid catalysis by imidazole, ring distortion, and electrostatic solvation or general base catalysis or covalent bond formation with a carboxyl group is proposed.

TL;DR: A solution is presented for the transient phase of a general enzyme mechanism and some of its properties are examined and these two parameters provide a means of differentiating among various proposed mechanisms.

TL;DR: In this paper, the dielectric constants and refractive indices for an oriented hydrocarbon assembly in bulk phase and a monolayer of infinite extent were calculated on the basis of Kirkwood's theory of dielectrics polarization.

TL;DR: There is substantial but not conclusive evidence that lymphoblastoid cell lines derived from normal individuals are made up of normal cells with an infinite life span, but it seems reasonable to suggest that some criteria for normalcy for one kind of cultured human cells in a restricted environment may not necessarily apply to other kinds of such cells.

TL;DR: The theory of partial orders is used to analyze a slightly more general problem than was originally posed in 1965, and the method for finding all the evolutionary hypotheses which satisfied this criterion was not known at that time.

TL;DR: In contrast with earlier models assuming the existence of two interacting oscillators in order to explain the temperature effects, the present model incorporates in a single oscillator the effects of both light and temperature on the system.

TL;DR: It is shown here that Shear's proof that an analog of the Boltzman H function provides a Liapunov function for open systems of chemical reactions is incorrect.

TL;DR: It was concluded that the small hibernating bat uses thermoregulatory mechanisms similar to those of normothermic homeotherms and Newton's Law of Cooling appears to be a valid approach to analysis of heat production and heat loss mechanisms in animals at any steady-state body temperature.

TL;DR: It is shown that intracellular magnesium increases with intrACEllular phosphorus for a wide variety of living systems and that the concentrations of these two elements are closely connected with the steady state activity of any one biological system.