On the Monadic Second-Order Transduction Hierarchy

We compare classes of finite relational structures via monadic second-order transductions. More precisely, we study the preorder where we set C \subseteq K if, and only if, there exists a transduction {\tau} such that C\subseteq{\tau}(K). If we only consider classes of incidence structures we can completely describe the resulting hierarchy. It is linear of order type {\omega}+3. Each level can be characterised in terms of a suitable variant of tree-width. Canonical representatives of the various levels are: the class of all trees of height n, for each n \in N, of all paths, of all trees, and of all grids

Electric and Galvanomagnetic Properties of Cd3As2–20 mol % MnAs Composite under High Pressure

Abstract: The pressure dependences of electrical resistance, Hall coefficient, charge carrier mobilities, and magnetoresistance of the Cd3As2–20 mol % MnAs composite are investigated at pressures up to 9 GPa. The pressure dependences of all the listed properties exhibit features related to phase transitions. The presence of pressure-induced negative magnetoresistance is registered. © 2020, Pleiades Publishing, Ltd

Effect of Hydrostatic Pressures of up to 9 GPa on the Galvanomagnetic Properties of Cd3As2–MnAs (20 mol % MnAs) Alloy in a Transverse Magnetic Field

Abstract—: We have studied the effect of hydrostatic pressure on the galvanomagnetic properties of a Cd3As2 + 20 mol % MnAs alloy in a transverse magnetic field of up to 4 kOe. The pressure dependences of the Hall coefficient and resistivity for the alloy provide evidence of reversible phase transitions. The observed negative magnetoresistance of the alloy is shown to be induced by high pressure. © 2019, Pleiades Publishing, Ltd

Use of Deschampsia antarctica for nest building by the kelp gull in the Argentine Islands area (maritime Antarctica) and its possible role in plant dispersal

During the last 50 years, the western coast of the Antarctic Peninsula and adjacent archipelagos, also known as the maritime Antarctic, has experienced notable climate warming. As a result, expansion of the local distributions of the two native species of vascular plants, Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth.) Bartl., over previously unoccupied ground has been noted. Birds have been suggested to be partially responsible for this spread. The focus of the present study was to document the use of vascular plants in nest building by the kelp gull (Larus dominicanus) in the Argentine Islands region. During the 2009/2010 season, samples from kelp gull nests were collected and analyzed. Besides nests, material lost by birds during transfer was also studied. We demonstrate that, in the Argentine Islands region, Deschampsia antarctica and some bryophytes contribute the majority of nest building material for the kelp gull. Other materials, including lichens, gull feathers, and limpet shells, are used less frequently. The plants can reestablish upon transfer via vegetative or generative means. It thus seems that the kelp gull may potentially serve as a dispersal agent for Deschampsia antarctica