Modular AWG-based Optical Shuffle Network

This paper proposes an arrayed-waveguide grating (AWG) based wavelength-division-multiplexing (WDM) shuffle network. Compared with previous optical shuffle networks, our proposal is compact, easy to implement, highly scalable, and cost effective

Thermohaline Fingerprints of the Greenland-Scotland Ridge and Fram Strait Subsidence Histories

Changes in ocean gateway configuration are known to induce basin-scale rearrangements in ocean characteristics throughout the Cenozoic. However, there is large uncertainty in the relative timing of the subsidence histories of ocean gateways in the northern high latitudes. By using a fully coupled General Circulation Model we investigate the salinity and temperature changes in response to the subsidence of two key ocean gateways in the northern high latitudes during early to middle Miocene. Deepening of the Greenland-Scotland Ridge causes a salinity increase and warming in the Nordic Seas and the Arctic Ocean. While warming this realm, deep water formation takes place at lower temperatures due to a shift of the convection sites to north off Iceland. The associated deep ocean cooling and upwelling of deep waters to the Southern Ocean surface causes a cooling in the southern high latitudes. These characteristic impacts in response to the Greenland-Scotland Ridge deepening are independent of the Fram Strait state. Subsidence of the Fram Strait for a deep Greenland-Scotland Ridge causes less pronounced warming and salinity increase in the Nordic Seas. A stronger salinity increase is detected in the Arctic while temperatures remain unaltered, which further increases the density of the North Atlantic Deep Water. This causes an enhanced contribution of North Atlantic Deep Water to the abyssal ocean and on the expense of the colder southern source water component. These relative changes largely counteract each other and cause little warming in the upwelling regions of the Southern Ocean

Ultrafast high-harmonic nanoscopy of magnetization dynamics

Light-induced magnetization changes, such as all-optical switching, skyrmion nucleation, and intersite spin transfer, unfold on temporal and spatial scales down to femtoseconds and nanometers, respectively. Pump-probe spectroscopy and diffraction studies indicate that spatio-temporal dynamics may drastically affect the non-equilibrium magnetic evolution. Yet, direct real-space magnetic imaging on the relevant timescale has remained challenging. Here, we demonstrate ultrafast high-harmonic nanoscopy employing circularly polarized high-harmonic radiation for real-space imaging of femtosecond magnetization dynamics. We observe the reversible and irreversible evolution of nanoscale spin textures following femtosecond laser excitation. Specifically, we map quenched magnetic domains and localized spin structures in Co/Pd multilayers with a sub-wavelength spatial resolution down to 16 nm, and strobosocopically trace the local magnetization dynamics with 40 fs temporal resolution. Our approach enables the highest spatio-temporal resolution of magneto-optical imaging to date. Facilitating ultrafast imaging with an extreme sensitivity to various microscopic degrees of freedom expressed in chiral and linear dichroism, we envisage a wide range of applications spanning magnetism, phase transitions, and carrier dynamics.Comment: 14 pages, 4 figure

Towards detecting swath events in TerraSAR-X time series to establish NATURA 2000 grassland habitat swath management as monitoring parameter

Spatial monitoring tools are necessary to respond to the threat of global biodiversity loss. At the European scale, remote sensing tools for NATURA 2000 habitat monitoring have been requested by the European Commission to fulfill the obligations of the EU Habitats Directive. This paper introduces a method by which swath events in semi-natural grasslands can be detected from multi-temporal TerraSAR-X data. The investigated study sites represent rare and endangered habitats (NATURA 2000 codes 6410, 6510), located in the Döberitzer Heide nature conservation area west of Berlin. We analyzed a time series of 11 stripmap images (HH-polarization) covering the vegetation period affected by swath (June to September 2010) at a constant 11-day acquisition rate. A swath detection rule was established to extract the swath events for the NATURA 2000 habitats as well as for six contrasting pasture sites not affected by swath. All swath events observed in the field were correctly allocated. The results indicate the potential to allocate semi-natural grassland swath events to 11-day-periods using TerraSAR-X time series. Since the conservation of semi-natural grassland habitats requires compliance with specific swath management rules, the detection of swath events may thus provide new parameters for the monitoring of NATURA 2000 grassland habitats.DLR/50EE092

Paleoelevation estimates for the northern and central proto–Basin and Range from carbonate clumped isotope thermometry

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99057/1/tect20016.pd

Detoxification Strategy of Epoxide Hydrolase

The human microsomal epoxide hydrolase, a single enzyme, has to detoxify a broad range of structurally diverse, potentially genotoxic epoxides that are formed in the course of xenobiotic metabolism. The enzyme has developed a unique strategy to combine a broad substrate specificity with a high detoxification efficacy, by immediately trapping the reactive compounds as covalent intermediates and by being expressed at high levels for high trapping capacity. Computer simulation and experimental data as well as existing epidemiologic studies reveal this detoxification strategy as the mechanistic basis for a threshold in the tumorigenesis of mutagenic carcinogens