Small impact cratering processes produce distinctive charcoal assemblages

The frequency of crater-producing asteroid impacts on Earth is not known. Of the predicted Holocene asteroid impact craters of <200 m diameter, only ~30% have been located. Until now there has been no way to distinguish them from “normal” terrestrial structures unless pieces of iron meteorites were found nearby. We show that the reflective properties of charcoal found in the proximal ejecta of small impact craters are distinct from those produced by wildfires. Impact-produced charcoals and wildfire charcoals must derive from different heating regimes. We suggest that charcoal with specific reflective properties may help to recognize the meteoritic origin of small craters.Marie Sklodowska-Curie grant ImpChar, agreement no. 749157; the 2016 Barringer Family Fund for Meteorite Impact Research (Arizona, USA); National Science Centre Poland grants 2020/39/D/ST10/02675 and 2013/09/B/ST10/01666

Drift-dependent changes in iceberg size-frequency distributions

Although the size-frequency distributions of icebergs can provide insight into how they disintegrate, our understanding of this process is incomplete. Fundamentally, there is a discrepancy between iceberg power-law size-frequency distributions observed at glacial calving fronts and lognormal size-frequency distributions observed globally within open waters that remains unexplained. Here we use passive seismic monitoring to examine mechanisms of iceberg disintegration as a function of drift. Our results indicate that the shift in the size-frequency distribution of iceberg sizes observed is a product of fracture-driven iceberg disintegration and dimensional reductions through melting. We suggest that changes in the characteristic size-frequency scaling of icebergs can be explained by the emergence of a dominant set of driving processes of iceberg degradation towards the open ocean. Consequently, the size-frequency distribution required to model iceberg distributions accurately must vary according to distance from the calving front

Siponimod (BAF312) prevents synaptic neurodegeneration in experimental multiple sclerosis

Data from multiple sclerosis (MS) and the MS rodent model, experimental autoimmune encephalomyelitis (EAE), highlighted an inflammation-dependent synaptopathy at the basis of the neurodegenerative damage causing irreversible disability in these disorders. This synaptopathy is characterized by an imbalance between glutamatergic and GABAergic transmission and has been proposed to be a potential therapeutic target. Siponimod (BAF312), a selective sphingosine 1-phosphate1,5 receptor modulator, is currently under investigation in a clinical trial in secondary progressive MS patients. We investigated whether siponimod, in addition to its peripheral immune modulation, may exert direct neuroprotective effects in the central nervous system (CNS) of mice with chronic progressive EAE

Low Viscosity, High Birefringence Liquid Crystalline Compounds And Mixtures

Two types of fast switching mixtures with high positive dielectric anisotropy were described. The first type, with a birefringence below 0.3, was designed for devices operating at room or lower temperatures and the second one, with a birefringence higher than 0.3 for devices operating at elevated temperatures

Sedimentary evidence of extreme storm surge or tsunami events in the southern Baltic Sea (Rogowo area, NW Poland)

The Baltic Sea is not typically considered as an area affected by tsunamis. However, during the Late Pleistocene and Holocene several tsunami events have been interpreted from the sedimentary record, mainly in Sweden and Estonia. Furthermore, on the southern coast of the Baltic Sea, there are historical accounts of catastrophical marine floodings called “der Seebär” (“the Sea Bear”). Their descriptions reveal many features typical for tsunami, but their genesis remained unknown and sedimentary evidence for such events has not been found. Here we provide evidence of sandy event layers from the area of Rogowo, NW Poland – the area of historical catastrophic storms as well as “der Seebär” events. The study area is a low-lying coastal plain with an average elevation of –0.5 to +0.5 m a.s.l., protected from the open sea by beach and coastal dune systems up to 5 m high. Sedimentological, micropalaeontological and geochemical analyses along with AMS 14C dating were applied to sedimentary successions seen in 5 major trenches and 198 sediment cores up to 1.5 m long. Two sandy layers were identified in the peat deposits that developed on the plain during the last ~2000 years. They reveal a number of typical features of tsunami deposits (significant lateral extent and thickness, rip-up clasts, chemical and micropalaeontological evidence of marine origin), however, 14C dating along with the historical accounts revealed that the major layer, extending at least 1.2 km from the modern coasts, was probably deposited by arguably the largest storm surge during the last 2000 years, which took place in 1497 AD. These storm deposits were likely formed during inundation of the low-lying coastal plain after major breaching of coastal dunes resulting in tsunami – like flow pattern and thus similar sedimentological effects. A discontinuous sand layer of younger age (18th century) and sharing similar properties to the previous one may be related to “der Seebär” event or another storm surge. The study revealed that the southern Baltic Sea coast may be affected by much greater coastal flooding than known from more recent accounts and observations. Thus, the presented geological record should be taken as an example of a worst-case scenario in coastal zone risk assessment from natural hazards. These events left sedimentary deposits that resemble tsunami deposits. It is likely that, in similar settings where storm surges cause unidirectional inundation of a coastal plain, it may not be possible to establish whether the resulting deposits were laid down from storms or tsunamis