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Biomedical subjects

G C Taylor

Publications and source records attributed to G C Taylor.

12 recordsLinked to original sources
PubMed1995

Scaling of elastic strain energy in kangaroos and the benefits of being big.

Large kangaroos are unique among mammals in their ability to uncouple aerobic metabolic energy costs from the speed of locomotion, making hopping an economical gait. During the first half of the ground-contact phase, kinetic energy lost from the body is stored as elastic strain energy, predominantly in the hind limbs. The subsequent recoil returns kinetic and potential energy to the body. Here we show that the allometry of structures in the legs and feet of Macropodoidea is different from that of quadrupedal eutherian mammals. The potential for elastic energy storage in hoppers is shown to scale with strong positive allometry. This is a function of the structural properties of muscle-tendon units in the distal hind limbs and the postures adopted by hopping kangaroos. Our findings demonstrate how the use of tissue elasticity is strongly mass dependent and help explain the observed energetic phenomena.

Animals↗
PubMed1995

Conditions under which Na+ channels can boost conduction of small graded potentials.

It has recently become apparent that in the dendrites or short axons of some neurons, voltage-dependent sodium channels are used not to generate action potentials but to modulate graded potentials; graded potentials carry far more information than do action potentials. A model axon (or dendrite) is described in which sodium channels with kinetics described by equations of the Hodgkin-Huxley type boost conduction of small voltage signals. For a sodium channel density beyond a certain minimum there exists an optimal potential, depolarized with respect to the resting potential, at which there is no steady-state decrement along the axon. For an axon not longer than about 0.7 length constants, small, steady-state deviations from this optimal potential imposed at one end of the axon appear amplified in a graded and stable way at the other end. A small pulse of potential is propagated with amplification and more rapidly than in an axon with a passive membrane. Compared to passive propagation, there will be an improvement in signal-to-noise ratio at the synapse; the axon also acts as a selective frequency filter. The same axon is capable of conducting an action potential.

Animals↗
PubMed1992

Effectiveness of an aerial application of carbaryl in controlling Ixodes dammini (Acari: Ixodidae) adults in a high-use recreational area in New Jersey.

Lyme disease risk reduction through the control of the principal tick vector, Ixodes dammini Spielman, Clifford, Piesman & Corwin, has become a major issue facing public health agencies in many endemic states. Where large tracts of land are involved, established methods of I. dammini control are impractical. An aerial application of carbaryl directed against fall populations of I. dammini adults resulted in 93.8% control after 96 h. Control persisted through the following spring. The usefulness of aerial applications may be limited to areas where logistic constraints obviate the use of conventional ground applications.

Aerosols↗
PubMed1991

In situ neutron spectrometry to 60 MeV in a water phantom exposed to a cancer therapy beam.

In-air and in-phantom neutron spectra have been measured between 10 and 60 MeV for two field sizes on the Clatterbridge cyclotron by unfolding the response of a specially built NE213 scintillator. The in-phantom measurements show distinct spectral hardening with depth, which is reflected in changes in the spectrum-averaged mean neutron energy. These findings are confirmed using Monte Carlo calculations.

Fast Neutrons↗
PubMed1991

Effectiveness of selected granular acaricide formulations in suppressing populations of Ixodes dammini (Acari: Ixodidae): short-term control of nymphs and larvae.

Applications of selected granular acaricide formulations to the shrub layer of forested habitats during the peak activity periods of Ixodes dammini Spielman, Clifford, Piesman & Corwin nymphs and larvae significantly reduced the abundance of these stages on Peromyscus leucopus. The granules effectively penetrated growing vegetation and suppressed populations of subadult ticks questing in the leaf litter. The use of granular acaricide formulations provides the only documented method of control of free-living I. dammini nymphs and larvae in dense vegetation. As such, this technique will serve as a major component of any integrated control program against this vector tick species.

Animals↗
PubMed1991

Lyme disease: a proposed ecological index to assess areas of risk in the northeastern United States.

BACKGROUND: Recent public awareness has resulted in a demand for information about ways to reduce the risk of acquiring Lyme disease. METHODS: Twenty-two school properties and recreational areas within a Lyme disease endemic area of central Monmouth County, New Jersey were evaluated for risk of transmission using an ecological index on the suitability, amount, and access to Ixodes dammini habitat by target human populations and the abundance of infected adult ticks. RESULTS: The characterization of tick habitat accurately predicted the elimination of 11 sites from concern. Of the remaining 11 sites, six were classified high risk and five as moderate risk. On-site tick surveys identified infected I. dammini adults at only four sites (three risk; one moderate risk). CONCLUSIONS: These results indicate that the use of selected ecological parameters provides a cost-effective method to rapidly identify areas at risk for Lyme disease transmission.

Animals↗
PubMed1981

Progressive supranuclear palsy: pneumoencephalography, electronystagmography and treatment with methysergide.

15 patients with progressive supranuclear palsy (PSP) are presented with discussion of the value of pneumoencephalography (PEG) and electronystagmography (ENG) in confirming the diagnosis. PEG was performed in 6 patients, and revealed atrophy in the area of the pons and colliculi. ENG, which also was performed in 6 patients, 4 of whom had PEG, confirmed the defects in extraocular movement. Methysergide, which has been suggested as therapy for PSP, was utilized in 6 patients with no evidence of significant improvement.

Aged↗
PubMed1969

Executive stress.

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Administrative Personnel↗