Leibniz University of Hanover

About: Leibniz University of Hanover is a education organization based out in Hanover, Niedersachsen, Germany. It is known for research contribution in the topics: Finite element method & Population. The organization has 14283 authors who have published 29845 publications receiving 682152 citations.

Cold dipolar gases in quasi-one-dimensional geometries

Abstract: We analyze the physics of cold dipolar gases in quasi-one-dimensional geometries, showing that the confinement-induced scattering resonances produced by the transversal trapping are crucially affected by the dipole-dipole interaction. As a consequence, the dipolar interaction may drastically change the properties of quasi-1D dipolar condensates, even for situations in which the dipolar interaction would be completely overwhelmed by the short-range interactions in a 3D environment.

Carbohydrates as Synthetic Tools in Organic Chemistry

Abstract: While amino acids, terpenes and alkaloids have found broad application as tools in stereoselective organic synthesis, carbohydrates have only lately been recognised as versatile starting materials for chiral auxiliaries, reagents, ligands and organocatalysts. The structural diversity of carbohydrates and the high density of functional groups offer a wide variety of opportunities for derivatization and tailoring of synthetic tools to a specific problem.

2-OGC: Open Gravitational-wave Catalog of binary mergers from analysis of public Advanced LIGO and Virgo data

Abstract: We present the second Open Gravitational-wave Catalog (2-OGC) of compact-binary coalescences, obtained from the complete set of public data from Advanced LIGO's first and second observing runs. For the first time we also search public data from the Virgo observatory. The sensitivity of our search benefits from updated methods of ranking candidate events including the effects of non-stationary detector noise and varying network sensitivity; in a separate targeted binary black hole merger search we also impose a prior distribution of binary component masses. We identify a population of 14 binary black hole merger events with probability of astrophysical origin $> 0.5$ as well as the binary neutron star merger GW170817. We confirm the previously reported events GW170121, GW170304, and GW170727 and also report GW151205, a new marginal binary black hole merger with a primary mass of $67^{+28}_{-17}\,\mathrm{M}_{\odot}$ that may have formed through hierarchical merger. We find no additional significant binary neutron star merger or neutron star--black hole merger events. To enable deeper follow-up as our understanding of the underlying populations evolves, we make available our comprehensive catalog of events, including the sub-threshold population of candidates and posterior samples from parameter inference of the 30 most significant binary black hole candidates.

Microbial stoichiometric flexibility regulates rice straw mineralization and its priming effect in paddy soil

Abstract: Nitrogen (N) and phosphorus (P) availability plays a crucial role in carbon (C) cycling in terrestrial ecosystems. However, the C:N:P stoichiometric regulation of microbial mineralization of plant residues and its impact on the soil priming effect (PE), measured as CO2 and CH4 emission, in paddy soils remain unclear. In this study, the effect of soil C:N:P stoichiometry (regulated by the application of N and P fertilizers) on the mineralization of 13C-labelled rice straw and the subsequent PE was investigated in a 100-day incubation experiment in flooded paddy soil. N and P additions increased straw mineralization by approximately 25% and 10%, respectively. Additions of both N and P led to higher CO2 efflux, but lower CH4 emission. With an increase in the ratios of DOC:NH4+-N, DOC:Olsen P, and microbial biomass C:N, 13CO2 efflux increased exponentially to a maximum. Compared with sole straw addition, exclusive N addition led to a weaker PE for CO2 emission, whereas exclusive P addition induced a stronger PE for CO2 emission. In contrast, CH4 emitted from native soil organic matter (SOM) was reduced by 7.4% and 46.1% following P and NP application, respectively. Structural equation models suggest that available N had dominant and direct positive effects, whereas microbial biomass stoichiometry mainly exerted negative indirect effects on PE. The stoichiometry of soil enzyme activity directly down-regulated CH4 emission from SOM. Microbes obviously regulate soil C turnover via stoichiometric flexibility to maintain an elemental stoichiometric balance between resources and microbial requirements. The addition of straw in combination with N and P fertilization in paddy soils could therefore meet microbial stoichiometric requirements and regulate microbial activity and extracellular enzyme production, resulting in co-metabolism of fresh C and native SOM.