The expedition LENA 2005

Introduction The purpose of the expedition LENA 2005 was to fill gaps of knowledge and to answer scientific questions that arose during former expeditions. Additionally, the monitoring program based at Samoylov Island was continued and expanded. Scientific investigations were focused on the following topics: A. Permafrost soils and ecosystems (• Chapter 3: Microbiological processes, trace gas fluxes and hydrobiology in permafrost ecosystems of the Lena Delta) B. Periglacial landscape dynamics (• Chapter 4: Studies of periglacial landscape dynamics and surface characteristics studies in the western Lena Delta) C. Ground ice as climate archive (• Chapter 5: Holocene ice wedges of the 1st Lena terrace) D. Modern delta hydrology (• Chapter 6: Report of the hydrological work in the Lena River Delta in August 2005

On Pure Spinor Superfield Formalism

We show that a certain superfield formalism can be used to find an off-shell supersymmetric description for some supersymmetric field theories where conventional superfield formalism does not work. This "new" formalism contains even auxiliary variables in addition to conventional odd super-coordinates. The idea of this construction is similar to the pure spinor formalism developed by N.Berkovits. It is demonstrated that using this formalism it is possible to prove that the certain Chern-Simons-like (Witten's OSFT-like) theory can be considered as an off-shell version for some on-shell supersymmetric field theories. We use the simplest non-trivial model found in [2] to illustrate the power of this pure spinor superfield formalism. Then we redo all the calculations for the case of 10-dimensional Super-Yang-Mills theory. The construction of off-shell description for this theory is more subtle in comparison with the model of [2] and requires additional Z_2 projection. We discover experimentally (through a direct explicit calculation) a non-trivial Z_2 duality at the level of Feynman diagrams. The nature of this duality requires a better investigation

Samoylov Deep Drilling Spring Campaign 2018

Permafrost thaw is associated with impacts on climate, land surface and coastal and river bank structures. Pro-cesses such as thermokarst and thermo-erosion lead to ground subsidence, which can have drastic e˙ects on the topography. One of the main drivers of surface subsidence vulnerability is the sedimentological composition, including ground ice content, and the temperature state of permafrost. This drilling campaign aimed to retrieve a deep, frozen sediment core from Samoylov Island to cover several scientific disciplines including geocryology, sedimentology and geochemistry. This campaign provides sample material from much greater depths (65.7 m) than previous boreholes on the island (27 m in 2006) and the anal-ysis of the sediments will therefore lead to a better understanding of the deep permafrost deposits on Samoylov Island. Furthermore, a temperature chain was installed in the borehole for long-term temperature monitoring