Yearbook 2013

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We discuss an application of contact topology to the space of foliations by surfaces on 3-manifolds. Without further geometric restrictions on the foliation, the connected components of the space of foliations are well understood. In contrast to this, if one requires that all foliations under consideration are taut, then the space of these foliations is more complicated. So far, its connected components are classified only in few special situations. more
We discuss the moduli space of solutions to Hitchin's selfduality equations and its connection with representation varieties. Afterwards some recent results concerning the degeneration profile of solutions for large Higgs fields will be presented. more
In applications, it is often desirable to obtain macroscopic properties of heterogeneous materials with microscopic structures. It is possible to obtain these by simulating a representative volume element. In order to do so efficiently, one requires accurate error estimates which are derived by combining ideas from analysis and probability theory. more
The RZG supports optimization of complex applications from plasma physics, astrophysics, materials science, and other disciplines for massively parallel high-performance computers and offers data management services and infrastructure for all phases of the data life cycle. Moreover, the RZG provides data visualization services for the exploration and quantitative analysis of simulation results. The RZG plays a leading role in projects within the MPG and at national and European level. more
An animal’s ability to respond to stress can be the difference between life and death when it is faced with an unfamiliar or inhospitable environment. Dr. Soojin Ryu at the MPI for Medical Research uses larval zebrafish to investigate how stress modifies brain and behavior. more
One of the most spectacular interactions of cells in the central nervous system is the myelination of axons by oligodendrocytes, which serves the rapid impulse propagation. Max Planck scientists have discovered a novel function of oligodendrocytes in the metabolic support of myelinated axons. Genetic evidence suggests that oligodendrocytes are glycolytic cells that release lactate as an energy-rich metabolite. Loss of this trophic function of oligodendrocytes may play a critical role in inherited and acquired myelin diseases. more
The increase in the prevalence of obesity and the concomitant health problems are putting a burden on our modern society. Lifestyle and genetic predisposition define the individual susceptibility to gain weight. Through identifying the genetic alterations and the subsequent investigation of the affected genes/proteins – including studies in mice – scientists hope to gain insights into the complex interaction of our genome and environment to finally identify the mechanisms that may lead e.g. to weight gain. more
Earth System models do not account for the limited availability of essential plant nutrients. Currently, about one third of the fossil fuel CO2 emissions is taken up by land ecosystems, but there is no guarantee that this ecosystem service will continue into the future. This study accounts for the first time for the availability of nitrogen and phosphorus on land. It shows that the omission of nutrient limitation in the models leads to an overestimation of carbon dioxide uptake by vegetation in future. Reduced CO2 uptake due to nutrient limitation will accelerate global warming. more
Turbulence controls how the atmospheric boundary layer mixes with the overlying free troposphere. This process is particularly important when stratocumulus clouds cap the atmospheric boundary layer. The details of how this mixing occurs have been investigated using direct numerical simulations. Specifically, the mixing due to evaporative cooling and local wind shear, and that due to radiative cooling, have been quantified separately, providing estimates for their relative strengths based on the bulk properties inside and above the cloud. more
Methane (CH4) is an important intermediate in the global carbon cycle. Per year about 1 Gt methane is formed from biomass and further oxidized to CO2. The formation of methane involves mainly anaerobic microorganisms, whereas in the oxidation of methane both anaerobic and aerobic microorganisms participate. In the atmosphere, where methane acts as a greenhouse gas, methane is predominantly re-mineralized photochemically. Investigations of the biochemistry of the methane cycle have led over and over again to new discoveries. On two of the most recent discoveries will be reported here. more
Iron-sulfur (Fe/S) clusters serve as ancient cofactors of proteins with a function in catalysis, electron transport and the regulation of gene expression. The synthesis of a Fe/S cluster and its insertion into target proteins is a complex process which in eukaryotes requires more than 30 proteins in mitochondria and cytosol. These components were analyzed both in vivo and in vitro for their molecular function and a mechanistic model of Fe/S protein biogenesis was proposed. In humans, malfunctions in this pathway cause numerous diseases. more
In order to study benthic phototrophs we developed a combination of high resolution chemical and community analyses that is widely applicable. The community structure is derived from spectra simultaneously recorded by a hyperspectral camera. A last step was to make the hyperspectral imager autonomous and useful for in situ approaches, even for deep sea deployment. Using these methods we will further intensify our research and investigate ecological hot spots for their productivity, such as coral reefs and sediments under sea-ice. more

Electric field as a switch for nanomagnets

Max Planck Institute of Microstructure Physics Brovko, Oleg O.; Ruiz-Diaz, Pedro; Dasa, Tamene R.; Stepanyuk, Valeri S.
“Electric Field as a Switch for Nanomagnets” – Nanomagnets are nowadays ubiquitously used as elementary building blocks for data storage devices. The constant strive for miniaturization of those building blocks calls for novel methods of controlling sub-nanoscale magnetic particles and molecules efficiently and selectively. At the Max Planck Institute of Microstructure Physics the effect of electric field on spin (magnetization) orientation and interaction of nanomagnets is studied (with first principles theoretical methods). more
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