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The cellular plains on Sputnik Planitia (SP) are thought to originate from convection in the nitrogen ice layer that fills the basin. Whereas the cells toward the center of SP's cellular plains are wider and interconnected—features explained by vigorous convection—the cells near the margins are smaller and less contiguous, with some appearing completely isolated. We propose that these isolated cells are surface expressions of localized convection—a rare planform in which stable thermal plumes can form in isolation from one another. Numerical simulations of convection using experimentally determined flow laws for power‐law creep in nitrogen ice show that for typical parameters of SP, the viscosity contrasts across the layer are sufficiently high for localization to occur. The diameter of the isolated cells provides constraints on the thickness of the nitrogen ice layer, the surface topographic anomaly, surface heat flow, and surface velocities associated with the localized cells.

One possible mechanism for Martian hemispherical dichotomy formation is excavation of the northern lowland basin in the existing crust by a single giant impact. Here we explore a related scenario in which the impact melt volume is sufficient to fill the excavated cavity, produce a thickened crust, and generate a topographic basin centered on the opposite side of the planet. We investigate this mechanism by formulating a model for viscous spreading of a partially molten layer over a spherical surface. We derive numerical solutions and calculate the final area of the spreading layer as a function of impactor size and shape of the layer boundary due to an initially asymmetric melt region. Results are compared with observations, including lowland basin size, shape of the dichotomy boundary, age difference between crustal provinces, and crustal thickness.

Several arguments point out that at the end of planetary accretion, the core of Mars was likely to be much hotter than its mantle, resulting in the formation of a completely or partially molten thermal boundary layer at the base of the mantle. Here we address the following questions: How did the superheated core cool and what role did it play in the early mantle dynamics of Mars? We divide the coupled core‐mantle evolution of early Mars into two stages. During the first stage, vigorous convection within the molten boundary layer removes the heat from the core so that the boundary layer expands up. As the boundary layer gets thicker, the temperature of the layer decreases. Eventually, the temperature of the molten boundary layer drops down to the temperature for the rheological transition (melt fraction ∼40%) within 100 years. This stage is described by a parameterized convection approach. The second stage is modeled in spherical shell geometry using the fully three‐dimensional finite element code CitcomS. A single plume (“superplume”) forms by the instability of the thermal boundary layer. The superplume stage lasts much longer, on the scale of millions to hundreds of millions of years, depending on the mantle viscosity. During both stages of evolution the heat flux can easily satisfy the requirements for the dynamo.

We use the long‐wavelength Venusian topography and geoid to constrain the global lithospheric thickness by assuming that the stagnant lid overlying the convective mantle is in isostatic equilibrium, the isostatic stagnant lid (ISL) approximation. Two‐dimensional and three‐dimensional numerical simulations of convection show that the ISL approximation is reasonably accurate in the tested parameter range of temperature‐dependant viscosity convection with bottom heating and internal heating. The errors in predicting the thickness of the stagnant lid (i.e., the lithosphere) are somewhat larger for internally heated convection. We attribute this to a flatter lid and, as a result, to a larger relative contribution to topography and geoid anomalies from the deeper parts of the layer. Application of the ISL approximation to Venus suggests that the average lithospheric thickness might be as large as 600 km, which is on the high end of previously proposed estimates. Key Points Thermal isostasy is a reasonably accurate model for a convecting system The magnitude of the dynamic topography is negligibly small Most of the Venusian topography can be explained by thermal isostasy

The isostatic stagnant lid (ISL) approximation is applied to the long‐wavelength Venusian topography and geoid to place constraints on the thickness of the crust and lithosphere. Previous studies showed that a purely thermal isostasy model of the lithosphere (the “stagnant lid”) accounts for a significant portion of the topography and geoid anomalies. Here we assume that the remaining discrepancy between the observed and model geoid is due to crustal thickness variations and that the crust, the lithosphere and the mantle are in a state of double isostatic equilibrium: the lithosphere is isostatically floating on top of the mantle and the crust is isostatically floating on top of the lithosphere. The addition of another variable, the crustal thickness, allows an exact fit to the observed topography and geoid. This also makes the solution non‐unique: an exact fit to topography and geoid can be achieved in a broad range of average lithospheric and crustal thicknesses. Additional constraints such as the gabbro‐eclogite phase transition and the existence of relatively young volcanism limit this range to some extent. The inferred variations in the crustal thickness are less sensitive to model assumptions and generally agree with the results obtained in previous studies. Key Points Venusian topography and geoid are fully explained by the crust and lithosphere A broad range of average thicknesses fit the observations Non‐uniqueness is reduced by additional constraints

The research outcomes of spatial and bathymetric distribution of dragon poacher Percis japonica are reported based on the bottom trawl surveys carried out in the Russian territorial waters in the Sea of Japan. The species can be found in the waters along the entire coastline. However, its spatial distribution pattern is variable. Thus, its distribution is sparse off the coasts of West Sakhalin, especially off the southern part of the island, while the species tends to congregate in the Peter the Great Bay and the Tatar Strait, where the locations of the species across these water areas remain almost unchanged throughout the year. With respect to the Northern Primorye Coastal Zone, the even distribution is typical for the entire water area, without any high congregation locations. Therefore, the dragon poacher can be found in wide ranges of depths and temperatures. However, its preferable ranges are substantially narrower. The highest values for available biomass resources are typical for the water areas off the Northern Primorye Coastal Zone.

Optically active polymers are of great interest as materials for dense enantioselective membranes, as well as chiral stationary phases for gas and liquid chromatography. Combining the versatility of norbornene chemistry and the advantages of chiral natural terpenes in one molecule will open up a facile route toward the synthesis of diverse optically active polymers. Herein, we prepared a set of new chiral monomers from cis-5-norbornene-2,3-dicarboxylic anhydride and chiral alcohols of various natures. Alcohols based on cyclic terpenes ((-)-menthol, (-)-borneol and pinanol), as well as commercially available alcohols (S-(-)-2-methylbutanol-1, S-(+)-3-octanol), were used. All the synthesized monomers were successfully involved in ring-opening metathesis polymerization, affording polymers in high yields (up to 96%) and with molecular weights in the range of 1.9 × 105–5.8 × 105 (Mw). The properties of the metathesis polymers obtained were studied by TGA and DSC analysis, WAXD, and circular dichroism spectroscopy. The polymers exhibited high thermal stability and good film-forming properties. Glass transition temperatures for the prepared polymers varied from −30 °C to +139 °C and, therefore, the state of the polymers changed from rubbery to glassy. The prepared polymers represent a new attractive platform of chiral polymeric materials for enantioselective membrane separation and chiral stationary phases for chromatography.

— The purplegray sculpin Gymnocanthus detrisus occurs at the depths between of 17 and 595 m at the temperature from –1.1 to+13.2°C off the mainland coast of the Russian waters of the Sea of Japan. In the warm period, the fish are concentrated in the middle and lower parts of the shelf, mainly at a temperature of 1.2–2.0°C, in the cold period, in the lower part of the shelf and the upper part of the continental slope at 0.6–1.4°C. The water area in the north (the waters of the Tatar Strait) is intensively used only in the warm season. The main aggregations are formed in the south (Peter the Great Bay) and in the areas of the central part of the surveyed region. Juveniles are more eurythermal than adult individuals and more adults prefer the shelf zone in all seasons, where the temperature regime is less stable than on the mainland slope.