Geology and cratering history of Ariel

The surface of Ariel imaged by Voyager 2 can be divided into several types of terrain on the basis of morphology: cratered terrain, subdued terrain, ridged terrain, and plains. Crater statistics were compiled for each of the terrain types. Despite differing morphology, the various terrains on Ariel do not exhibit large variations in crater frequency. None of the observed surfaces on Ariel record the period of accretion. It seems that conditions appropriate for resurfacing could have occurred during the early history of Ariel

Cratering history of Miranda

The surface of the southern hemisphere of Miranda imaged by Voyager 2 is divisible into two general types of terrain: cratered terrain, characterized by numerous craters and undulating intercrater plains; and basins, circular to rectangular areas of complex morphology having large-scale albedo markings. To determine the relative ages of the terrains and the length of geological activity, crater-frequency data were compiled for various parts of the cratered terrain and basins. Crater-frequency data indicate that the cratered terrain is the oldest terrain on Miranda and that it was locally resurfaced

Gravity survey of the Mt. Toondina impact structure, South Australia

The Mt. Toondina impact structure is located in northern South Australia, about 45 km south of the town of Oodnadatta. Only the central uplift is exposed. The outcrops at Mt. Toondina reveal a remarkable structural anomaly surrounded by a broad expanse of nearly flat-lying beds of the Bulldog Shale of Early Cretaceous age. A gravity survey was undertaken in 1989 to determine the diameter of the impact structure, define the form of the central uplift, and understand the local crustal structure. Data were collected along two orthogonal lines across the structure. In addition to the profiles, a significant number of measurements were made on and around the central uplift. The 1989 gravity data combined with 1963 gravity data and the seismic reflection data provide an excellent data base to interpret the subsurface structure of the Mt. Toondina feature

Interactions of tectonic, igneous, and hydraulic processes in the North Tharsis Region of Mars

Recent work on the north Tharsis of Mars has revealed a complex geologic history involving volcanism, tectonism, flooding, and mass wasting. Our detailed photogeologic analysis of this region found many previously unreported volcanic vents, volcaniclastic flows, irregular cracks, and minor pit chains; additional evidence that volcanic tectonic processes dominated this region throughout Martian geologic time; and the local involvement of these processes with surface and near surface water. Also, photoclinometric profiles were obtained within the region of troughs, simple grabens, and pit chains, as well as average spacings of pits along pit chains. These data were used together with techniques to estimate depths of crustal mechanical discontinuities that may have controlled the development of these features. In turn, such discontinuities may be controlled by stratigraphy, presence of water or ice, or chemical cementation

Does wrinkle ridge formation on Mars involve most of the lithosphere

Recent work on the origin of wrinkle ridges suggests that they are compressional tectonic features whose subsurface structure is not understood. Some characteristics of Martian wrinkle ridges are reviewed which suggest that they are the surface expression of thrust faults that extend through much of the lithosphere

Do party supporters accept policy compromises in coalition governments?

Coalition governments generally involve policy compromises from the parties involved, but how do party supporters react to these agreements? Drawing on a new study covering the Spanish general election in November 2019, Carolina Plescia, Alejandro Ecker and Thomas M. Meyer find that the more attached voters are to parties, the harder it is for them to accept compromises. There is also evidence that voters find it more difficult to give in on important issues

Synthesis and biological evaluation of new indazole derivatives

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Musculoskeletal disorders and incongruous postures in workers on ropes: A pilot study

Background:Occupational hazards believed to cause musculoskeletal disorders in rope workers are traditionally associated with maintaining incongruous postures for prolonged periods of time. Design and methods:A cross-sectional survey was conducted on 132 technical operators in the wind energy and acrobatic construction sectors, who work on ropes, analysing the ergonomic characteristics of the environments, the way in which tasks are carried out, the strain perceived by individual workers, and assessing the presence of any musculoskeletal disorders (MSDs) by means of an objective examination focused on the anatomical districts that were the object of our study. Results:Analysis of the data obtained showed that there were differences in the perception of the level of physical intensity and perceived exertion between the groups of workers. Statistical analysis also revealed a significant association between the frequency of MSDs analysed and perceived exertion. Discussion:The most significant finding to emerge from this study is the high prevalence of MSDs of the cervical spine (52.94%), the upper limbs (29.41%), and the dorso-lumbar spine (17.65%). These values differ from those classically found in those exposed to the risk of conventional manual handling of loads. Conclusions:The high prevalence of disorders of the cervical spine, the scapulo-humeral girdle and the upper limbs, indicates the need to consider the forced position to be assumed for a large part of the work activity, staticity, and the inability to move the lower limbs for long periods as the predominant risk in rope work

Synthesis, antiproliferative activity, and mechanism of action of a series of 2-{[2E]-3-phenylprop-2-enoylamino}benzamides

Several new 2-{[2E]-3-phenylprop-2-enoylamino}benzamides 12a-s and 17t-v were synthesized by stirring in pyridine the (E)-3-(2-R1-3-R2-4-R3-phenyl)acrylic acid chlorides 11c-k and 11t-v with the appropriate anthranilamide derivatives 10a-c or the 5-iodo anthranilic acid 13. Some of synthesized compounds were evaluated for their in vitro antiproliferative activity against the full NCI tumor cell line panel derived from nine clinically isolated cancer types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate and breast). COMPARE analysis, effects on tubulin polymerization in cells and with purified tubulin, and effects on cell cycle distribution for 17t, the most active of the series, indicate that these new antiproliferative compounds act as antitubulin agent

Experimental Impacts into Strength-Layered Targets: Ejecta Kinematics

AImpact cratering has dominated the evolution and modification of planetary surfaces through-out the history of the solar system. Impact craters can serve as probes to understanding the details of a planetary subsurface; for example, Oberbeck and Quaide, suggested that crater morphology can be used to estimate the thickness of a regolith layer on top of a more competent unit. Lunar craters show a morphological progression from a simple bowl shape to flat-floored and concentric craters as crater diameter in-creases for a given regolith thickness. The final shape of the impact crater is a result of the subsurface flow-field initiated as the projectile transfers its energy and momentum to the target surface at the moment of impact. Therefore, when a regolith layer is present over a stronger substrate, such as is the case on the lunar surface, the substrate modifies the flow-field and thereby the excavation flow of the crater, which is reflected in the morphology of the final crater. Here we report on a series of experimental impacts into targets composed of a thin layer of loose sand on top of a stronger substrate. We use the Ejection-Velocity Measurement System developed to examine the ejecta kinematics during the formation of these craters