Abnormal polarity of thunderclouds grown from negatively charged air

Experiments were carried out in New Mexico to determine whether the electrification processes that lead to the formation of lightning in clouds are influenced by the polarity of the charges in the air from which the clouds grow. The normal, positive space charge in the sub-cloud air was reversed by negative charge released from an electrified wire, suspended across a 2-kilometer-wide canyon. On more than four occasions when the clouds over the wire grew and became electrified, they were of abnormal polarity with dominant positive charges instead of the usual negative charges in the lower part of the cloud. The formation of these abnormally electrified clouds suggests both that the electrification process in thunderclouds can be initiated and that its polarity may be determined by the small charges that are present in the atmosphere.     

Assembly of clathrin-coated pits onto purified plasma membranes

During receptor-mediated endocytosis, coated pits invaginate to form coated vesicles, clathrin and associated proteins dissociate from the vesicle membrane, and these proteins form new coated pits at the cell surface. As a means of elucidating molecular mechanisms that govern the function of coated pits, the assembly phase of this cycle was reconstituted by incubating purified membranes that were treated to remove endogenous coated pits with cytoplasm extracted from cultured cells. The in vitro assembly of coated pits on these membranes satisfactorily mimics many features of coated pit formation in the intact cell. These studies indicate that: the membranes contain a limited number of coated pit assembly sites that bind clathrin with high affinity; the half-time for assembly is 5 minutes both at 4 degrees C and 37 degrees C; during assembly, proteins with molecular sizes of 180, 110, and 36 kilodaltons are recruited to the plasma membrane; and assembly is not dependent on adenosine triphosphate, but this nucleotide triggers a temperature-dependent loss of coated pits that are assembled in the absence of adenosine triphosphate.     

Visual pathway mediating pineal response to environmental light

Activity of the melatoninforming enzyme, hydroxyindole-O-methyltransferase, in rat pineal is increased when the animal is exposed to continuous darkness, and it is decreased by exposure to continuous light. Response to environmental light is initiated in the retina and transmitted to the pineal by way of the central nervous system and the cervical sympathetics. The central visual pathway essential for mediation of this response is the inferior accessory optic tract. Visual pathways to thalamus and tectum do not participate in this response.     

Radar characteristics of viking 1 landing sites

Radar observations of Mars at centimeter wavelengths in May, June, and July 1976 provided estimates of surface roughness and reflectivity in three potential landing areas for Viking 1. Surface roughness is characterized by the distribution of surface landing slopes or tilts on lateral scales of the order of 1 to 10 meters; measurements of surface reflectivity are indicators of bulk surface density in the uppermost few centimeters. By these measures, the Viking 1 landing site at 47.5 degrees W, 22.4 degrees N is rougher than the martian average, although it may be near the martian average for elevations accessible to Viking, and is estimated to be near the Mars average in reflectivity. The AINW site at the center of Chryse Planitia, 43.5 degrees W, 23.4 degrees N, may be an area of anomalous radar characteristics, indicative of extreme, small-scale roughness, very low surface density, or a combination of these two characteristics, Low signal-to-noise ratio observations of the original Chryse site at 34 degrees W, 19.5 degrees N indicate that that area is at least twice as rough as the Mars average.