Galileo at Io: results from high-resolution imaging

During late 1999/early 2000, the solid state imaging experiment on the Galileo spacecraft returned more than 100 high-resolution (5 to 500 meters per pixel) images of volcanically active Io. We observed an active lava lake, an active curtain of lava, active lava flows, calderas, mountains, plateaus, and plains. Several of the sulfur dioxide-rich plumes are erupting from distal flows, rather than from the source of silicate lava (caldera or fissure, often with red pyroclastic deposits). Most of the active flows in equatorial regions are being emplaced slowly beneath insulated crust, but rapidly emplaced channelized flows are also found at all latitudes. There is no evidence for high-viscosity lava, but some bright flows may consist of sulfur rather than mafic silicates. The mountains, plateaus, and calderas are strongly influenced by tectonics and gravitational collapse. Sapping channels and scarps suggest that many portions of the upper approximately 1 kilometer are rich in volatiles.     

Inferior olive of the cat: intracellular recording

The action potential evoked from inferior olivary neurons of the cat by orthodromic, antidromic, or intracellular stimulation has a large prolonged depolarization, frequently with several superimposed smaller spikes. The all-or-nothing unitary response appears to be a property of the cell, and the later spikes are not secondary to synaptic excitation by recurrent axon collaterals.     

Mars gravity: high-resolution results from viking orbiter 2

Doppler radio-tracking data have provided detailed measurements for a martian gravity map extending from 30 degrees S to 65 degrees N in latitude and through 360 degrees of longitude. The feature resolution is approximately 500 kilometers, revealing a huge anomaly associated with Olympus Mons, a mascon in Isidis Planitia, and other anomalies correlated with volcanic structure. Olympus Mons has been modeled with a 600-kilometer surface disk having a mass of 8.7 x 1021grams.     

Nerv-end recording in conducting volume

When the end of a freshly cut nerve is drawn into a tube by means of a hydraulic device that serves as a holder and as an electrode, monophasic positive records of action potentials are recorded. A trailing positive phase develops, with time, after the cut. After-potentials can also be recorded by this method.     

Lunar thermal anomalies: infrared observations

The lunar craters Tycho, Copernicus, and Aristarchus have been observed during lunar night at wavelengths between 3 and 14 microns. After an initial fast decrease to a color temperature of 220 degrees K, the temperature remains nearly constant through the lunar night. The data suggest that these thermal anomalies (craters) contain hot and cold regions with the hot portions constituting 2 to 10 percent of the area and probably thermally connected to a subsurface temperatuer of about 200 degrees K.     

Saturn's temperature field from high-resolution middle-infrared imaging

Saturn was imaged between 8 and 24.5 micrometers at approximately 3000-kilometer resolution with the Keck I Telescope. Saturn's atmosphere has zonal temperature bands, which are mostly uncorrelated with visible cloud reflectivity, strong 100-millibar zonal temperature oscillations near 32 degrees S, a warm south polar cap, and a compact hot point within 3 degrees of the south pole.     

Long-term activity recording in small aquatic animals

We have built an activity-recording device based on the principle of detecting slight changes in the heat conductance of an aquatic environment by means of a thermistor. A major advantage of the device is that it can be used with a simple event recorder, thus combining high sensitivity with low cost. The equipment has been tested with automatic mechanical stimulation, and has been used for long-term recording of the swimming of small marine crustaceans. Problems of stability and reliability have been solved, and potential applications of the device seem widespread.     

Contact photomicrography in the ultraviolet on high-resolution plates

Ultraviolet photographs of cells can be made without quartz optics by placing the cells on high-resolution plates capable of resolving more than 2000 lines per millimeter and by passing monochromatic radiation of the desired wavelength through them to the emulsion. Prints can be made by enlarging the resulting negative with a microscope to the magnification desired.     

Telemetered recording of hormone effects on hippocampal neurons

Frequency-modulated telemetry was used to record the effects of hormones on single-unit activity in the brains of freely moving rats. Corticosterone decreased unit activity in the dorsal hippocampus. Adrenocorticotrophic hormone had the opposite effect.     

Satellites of the outer planets: thermal models

Steady-state thermal models for the large satellites of the outer planets strongly indicate that their interiors are currently maintained at temperatures well above the ice-ammonia eutectic temperature by the decay of long-lived radioisotopes of potassium, uranium, and thorium. The present-day steady-state thermal structure of a representative satellite, J IV (Callisto), is shown to be characterized by the presence of a thin icy crust over a deep liquid mantle, with a dense core of hydrous silicates and iron oxides. Some dynamical consequences of this model are briefly discussed.