A region‐by‐region condensed description of almost all of the area that was radar‐photographed by Veneras 15 and 16 is presented. Using some generalizations, the diversity of terrain was reduced to a discrete set from which a geological‐morphological map was constructed. The predominant type of terrain of the studied area is a plain that was tentatively subdivided into five morphological types: ridge‐and‐band, patchy rolling plain, dome‐and‐butte plain, smooth plain, and high smooth plain. Stratigraphically, the ridge‐and‐band plains are the oldest and the smooth plains are the youngest. The stratigraphic position of the other types is yet to be determined. Large sections of the plains show similarities to the mare‐type basaltic plains of the moon, Mercury, and Mars. Other types of terrain are combinations of ridges and grooves in various patterns: linear parallel, orthogonal, diagonal or chevron‐like, and chaotic. In some places the ridge‐and‐groove terrain is Stratigraphically below the plain material, but in other places it appears to be plain material that has been subsequently deformed. Near the eastern and western boundaries of Ishtar Terra large (several hundred kilometers in diameter) ring‐like features can be seen that are named coronae or ovoids. Evidence of tectonic deformation and the presence of flow‐like patterns support their designation as volcano‐tectonic features. Beta Regio seems to be an uplifted plain showing evidence of rifting and volcanism. All types of terrain are sparesely peppered with craters of obvious impact morphology. Their average density gives the plain an age range of 0.5 to 1×109 years. The fact that many impact craters are still in the pristine state indicates a very low rate of surface reworking, at least for the last 0.5 to 1×109 years. No evidence for water‐erosion‐sedimentation processes has been found. The tectonic activity of Venus has no equivalent on the moon, Mercury, or even Mars, and can be compared only with that of the Earth. Intensive horizontal deformation, previously known only on Earth, occurs on Venus, but in a characteristic Venusian style.

Analysis of the radar images obtained by Veneras 15 and 16 leads to the conclusion that the ridge‐and‐groove structures on the surface of Venus are the result of tectonic deformation. Although the mechanism of such deformation cannot yet be unequivocally deduced, several styles of deformation can be described. Areal deformation occurs where horizontal stresses have operated over large areas. Shear deformation appears in bands showing differential longitudinal deformation. Transversal stresses operating over long and relatively narrow areas have produced belt deformation. Circular deformation is related to a specific locus of the stresses. The absence of densely cratered areas indicates that the terrains were deformed after the period of heavy bombardment. The origin of the stresses could be drag of the lithosphere by asthenospheric currents or gravity‐induced spreading of surface material over upwellings. A general conclusion is that in the surveyed area of Venus neither terrestrial plate tectonics nor lunar‐highland‐type terrain exists.

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We demonstrate on synthetic eumelanin that biomolecular conductivity models should account for temperature and hydration effects coherently.

The results of wide-range measurements of the low-frequency, rf, and microwave conductivity in the typical mixed-valent narrow-gap semiconductor samarium hexaboride are presented. The established steplike anomaly of conductivity ͑͒ around 10 GHz is discussed in the framework of the exciton-polaron approach and coherent-state formation in SmB 6 at helium temperatures. A combined analysis of the dc-and wide-range ac-transport characteristics and dielectric permittivity data at low temperatures is developed.