The state and the church in Russia in the early new age: custom and law

The article is devoted to the analysis of the peculiarities of the system of relations that were formed between the Orthodox Church and the authority of the Russian state in the early modern perio

Factors influencing graphene growth on metal surfaces

Graphene forms from a relatively dense, tightly-bound C-adatom gas, when elemental C is deposited on or segregates to the Ru(0001) surface. Nonlinearity of the graphene growth rate with C adatom density suggests that growth proceeds by addition of C atom clusters to the graphene edge. The generality of this picture has now been studied by use of low-energy electron microscopy (LEEM) to observe graphene formation when Ru(0001) and Ir(111) surfaces are exposed to ethylene. The finding that graphene growth velocities and nucleation rates on Ru have precisely the same dependence on adatom concentration as for elemental C deposition implies that hydrocarbon decomposition only affects graphene growth through the rate of adatom formation; for ethylene, that rate decreases with increasing adatom concentration and graphene coverage. Initially, graphene growth on Ir(111) is like that on Ru: the growth velocity is the same nonlinear function of adatom concentration (albeit with much smaller equilibrium adatom concentrations, as we explain with DFT calculations of adatom formation energies). In the later stages of growth, graphene crystals that are rotated relative to the initial nuclei nucleate and grow. The rotated nuclei grow much faster. This difference suggests first, that the edge-orientation of the graphene sheets relative to the substrate plays an important role in the growth mechanism, and second, that attachment of the clusters to the graphene is the slowest step in cluster addition, rather than formation of clusters on the terraces

Sediment release of dissolved organic matter in the oxygen minimum zone off Peru

In combination to sluggish ventilation by ocean currents, the nutrient upwelling and high surface productivity, followed by organic matter remineralization, leads to a pronounced oxygen minimum zone (OMZ) in the eastern tropical South Pacific (ETSP). There, oxygen concentrations drop below 1 �mol/kg at a water depth <80 m. The high productivity results in the supply of organic matter (OM) to the anoxic sediments and its utilization by heterotrophic communities. The microbial utilization of OM under anoxia leads to nitrogen loss processes, and an accumulation of sulphide and methane. The proximity of the OMZ to the ocean surface in the ETSP may lead to an active outgassing of climate relevant products of the anoxic OM remineralization. The degradation of OM in sediments is associated with production of dissolved organic matter (DOM) from organic particles (POM) that is further remineralized into inorganic nutrients and dissolved inorganic carbon, which then can be released back to the water column, fuelling productivity. Part of the DOM pool may be released to the overlying water column and serve as ligands for micronutrients, such as iron, or provide an additional substrate for microbial communities to respire, affecting overlying water column biogeochemistry. Despite the potential relevance for biogeochemical processes, the quality of the DOM in the pore waters that may be released to the overlying water column has been barely studied in the ETSP off Peru. High spatial resolution measurements of DOM fluorescence (FDOM) during the research cruise M93 (Feb-March 2013) indicated elevated intensities near the sediments in the ETSP off Peru. Those intensities were interpreted as a sediment release of DOM, the quantification of dissolved organic carbon (DOC) flux, however, was not possible at the time. To estimate DOM fluxes and DOM quality, DOC and DOM samples were collected from the sediment pore waters and from benthic incubation chambers from six stations along the 12°S transect in the Peruvian upwelling in 2017 (cruises M136, M137). Samples were collected using a multiple-corer and by Biogeochemical Observatories, respectively. Here, we evaluate DOC fluxes from the sediments and relate them to the measurements of FDOM. We evaluate the quality of DOM by Excitation Emission spectroscopy, followed by parallel factor analysis. The possible implications of the DOM release for water column biogeochemistry are discussed

Water column biogeochemistry of oxygen minimum zones in the eastern tropical North Atlantic and eastern tropical South Pacific Oceans

Recent modeling results suggest that oceanic oxygen levels will decrease significantly over the next decades to centuries in response to climate change and altered ocean circulation. Hence the future ocean may experience major shifts in nutrient cycling triggered by the expansion and intensification of tropical oxygen minimum zones (OMZs). There are numerous feedbacks between oxygen concentrations, nutrient cycling and biological productivity; however, existing knowledge is insufficient to understand physical, chemical and biological interactions in order to adequately assess past and potential future changes. We investigated the pelagic biogeochemistry of OMZs in the eastern tropical North Atlantic and eastern tropical South Pacific during a series of cruise expeditions and mesocosm studies. The following summarizes the current state of research on the influence of low environmental oxygen conditions on marine biota, viruses, organic matter formation and remineralization with a particular focus on the nitrogen cycle in OMZ regions. The impact of sulfidic events on water column biogeochemistry, originating from a specific microbial community capable of highly efficient carbon fixation, nitrogen turnover and N2O production is further discussed. Based on our findings, an important role of sinking particulate organic matter in controlling the nutrient stochiometry of the water column is suggested. These particles can enhance degradation processes in OMZ waters by acting as microniches, with sharp gradients enabling different processes to happen in close vicinity, thus altering the interpretation of oxic and anoxic environments

Climate-Biogeochemistry Interactions in the Tropical Ocean: Data collection and legacy

From 2008 through 2019, a comprehensive research project, SFB 754, Climate - Biogeochemistry Interactions in the Tropical Ocean, was funded by the German Research Foundation to investigate the climate-biogeochemistry interactions in the tropical ocean with a particular emphasis on the processes determining the oxygen distribution. During three 4-year long funding phases, a consortium of more than 150 scientists conducted or participated in 34 major research cruises and collected a wealth of physical, biological, chemical, and meteorological data. A common data policy agreed upon at the initiation of the project provided the basis for the open publication of all data. Here we provide an inventory of this unique data set and briefly summarize the various data acquisition and processing methods used

Modeling morphological instabilities in lipid membranes with anchored amphiphilic polymers

Anchoring molecules, like amphiphilic polymers, are able to dynamically regulate membrane morphology. Such molecules insert their hydrophobic groups into the bilayer, generating a local membrane curvature. In order to minimize the elastic energy penalty, a dynamic shape instability may occur, as in the case of the curvature-driven pearling instability or the polymer-induced tubulation of lipid vesicles. We review recent works on modeling of such instabilities by means of a mesoscopic dynamic model of the phase-field kind, which take into account the bending energy of lipid bilayers