The Colour Changes In Lizards, Particularly In Phrynosoma

The activities of the melanophore system of Phrynosoma in comparison with that of Chamaeleo may be stated categorically in the following way. I. The blanching of Phrynosoma blainvillii is due (1) to the action of its concentrating nerve-fibres on its melanophores, (2) to the action of a hydrohumour, probably adrenalin, on the same cells, (3) to the direct response of these cells to darkness, and (4) to high temperatures. II. The blanching of Chamaeleo is due to the first, third, and fourth of these factors. Whether the second factor is effective in this lizard is not yet determined. III. The darkening of Phrynosoma is due (5) to the action of a pituitary neurohumour on its melanophores, (6) to the direct response of these cells to strong light, and (7) usually, to low temperatures. There are no dispersing nerve-fibres known in Phrynosoma. IV. The darkening of Chamaeleo is due to the sixth and probably to the seventh of these factors. This lizard presents strong indications of possessing dispersing nerve-fibres. Whether it darkens from a pituitary neurohumour or not is unknown

Forest and range mapping in the Houston area with ERTS-1

ERTS-1 data acquired over the Houston area has been analyzed for applications to forest and range mapping. In the field of forestry the Sam Houston National Forest (Texas) was chosen as a test site, (Scene ID 1037-16244). Conventional imagery interpretation as well as computer processing methods were used to make classification maps of timber species, condition and land-use. The results were compared with timber stand maps which were obtained from aircraft imagery and checked in the field. The preliminary investigations show that conventional interpretation techniques indicated an accuracy in classification of 63 percent. The computer-aided interpretations made by a clustering technique gave 70 percent accuracy. Computer-aided and conventional multispectral analysis techniques were applied to range vegetation type mapping in the gulf coast marsh. Two species of salt marsh grasses were mapped

Design considerations and test facilities for accelerated radiation effects testing

Test design parameters for accelerated dose rate radiation effects tests for spacecraft parts and subsystems used in long term mission (years) are detailed. A facility for use in long term accelerated and unaccelerated testing is described

Jupiters radiation belts and their effects on spacecraft

The effects of electron and proton radiation on spacecraft which will operate in the trapped radiation belts of the planet Jupiter are described, and the techniques and results of the testing and simulation used in the radiation effects program are discussed. Available data from the Pioneer 10 encounter of Jupiter are compared with pre-encounter models of the Jupiter radiation belts. The implications that the measured Jovian radiation belts have for future missions are considered

Structure formation during the collapse of a dipolar atomic Bose-Einstein condensate

We investigate the collapse of a trapped dipolar Bose-Einstein condensate. This is performed by numerical simulations of the Gross-Pitaevskii equation and the novel application of the Thomas-Fermi hydrodynamic equations to collapse. We observe regimes of both global collapse, where the system evolves to a highly elongated or flattened state depending on the sign of the dipolar interaction, and local collapse, which arises due to dynamically unstable phonon modes and leads to a periodic arrangement of density shells, disks or stripes. In the adiabatic regime, where ground states are followed, collapse can occur globally or locally, while in the non-adiabatic regime, where collapse is initiated suddenly, local collapse commonly occurs. We analyse the dependence on the dipolar interactions and trap geometry, the length and time scales for collapse, and relate our findings to recent experiments.Comment: In this version (the published version) we have slightly rewritten the manuscript in places and have corrected some typos. 15 pages and 13 figure

Spatial curvature effects on molecular transport by diffusion

For a substance diffusing on a curved surface, we obtain an explicit relation valid for very small values of the time, between the local concentration, the diffusion coefficient, the intrinsic spatial curvature and the time. We recover the known solution of Fick's law of diffusion in the flat space limit. In the biological context, this result would be useful in understanding the variations in the diffusion rates of integral proteins and other molecules on membranes.Comment: 10 page