ALBERT

Description: We examine the simulated Atlantic Multidecadal Variability (AMV) in a model that includes a correction for a longstanding problem with climate models, namely the misplacement of the North Atlantic Current. The corrected model shows that in the warm AMV phase, heat is lost by the ocean in the northwestern part of the basin and gained by the ocean to the east, suggesting an advective transfer of heat by the mid-latitude westerlies. The basin wide response is consistent with a role for cloud feedback and is in broad agreement with estimates from observations, but is poorly represented in the uncorrected model. The corrected model is then used to show that the ocean/atmosphere heat transfer is influenced by low frequency variability in the overlying atmosphere. We also argue that changing ocean heat transport is an essential feature of our results.

Description: [1]  We report systematic measurements of the distribution of the incident angle of interstellar pickup He + ions as observed by STEREO/PLASTIC. We have organized these observations according to the angle spanned by the Interplanetary Magnetic Field (IMF), , and the bulk solar wind velocity, v sw . Our measurements show clear evidence of a relatively local injection of He + pickup ions into the solar wind, which are then seen as a ring distribution perpendicular to . Changes of the spectral shape and a reduced flux of interstellar He + during radial IMF configuration, as observed by e.g. Ulysses/SWICS, SOHO/CTOF, AMPTE/SULEICA, have generally been attributed to inefficient scattering across 90° pitch-angle. Our observations of the pitch-angle distribution of interstellar He + suggest that these changes are instead a result of locally injected pickup ions that escape detection for IMF configuration in which the Solar Wind Sector of PLASTIC, as well as SWICS, CTOF, and SULEICA, are not sensitive to the measurement of the locally injected pickup ion ring.

Description: The existing screening and characterization systems for biocatalysts operate in batch mode, which could make catalyst selection and process development inaccurate when continuous operation mode is required in industry. A significant improvement of an innovative screening system based on miniaturized multiple membrane reactors formerly presented by the author is outlined, which enables continuous feeding of substrates and continuous removal of products. Although the presented screening system was originally designed for homogeneous enzymatic reactions, it can be used without further modifications for continuous catalysis with polymer-bound chemical catalysts or for quasi-homogeneous systems like reverse micelles. Currently available screening and characterization systems for biocatalysis are not sufficiently suitable for process description and scale-up of results to pilot- or full-scale reactors often operated in continuous mode. Hydrolysis of N -acetyl- L -methio-nine served as model reaction for an innovative continuous characterization system, implementing a precise dosing system.

Description: Silicone composites of Novozym®435 ( silcoat -NZ435) demonstrate improved leaching and mechanical stability compared to native Novozym®435 (NZ435). Here, the application scope of this novel enzyme preparation has been broadened significantly by the transfer from single-phase esterification to a complex chemo-enzymatic epoxidation reaction in a three-phase system. The reaction gave up to 80 % yields with almost 100 % selectivity in 50 h when operated in the absence of mass transfer limitations. Characterization of the system revealed that octanoic acid inhibited the reaction at concentrations around 6 M. The silcoat -NZ435 catalyst could be reused over five days with less than 50 % loss in activity when 5 M H 2 O 2 was present. H 2 O 2 was also identified as the component which deactivates the enzyme at high concentration (17.5 M) demanding spatial separation of the silcoat -NZ435 for optimal operation. silcoat -NZ435 was successfully applied to biocatalyze a solvent-free chemo-enzymatic epoxidation reaction of a model alkene 1-dodecene in a multiphase system. The system was operated without mass transfer limitations and provided yields of up to 80 % and excellent selectivity of almost 100 % for the reaction.

Description: Although stress can suppress growth and proliferation, cells can induce adaptive responses that allow them to maintain these functions under stress. While numerous studies have focused on the inhibitory effects of stress on cell growth, less is known on how growth-promoting pathways influence stress responses. We have approached this question by analyzing the effect of mammalian target of rapamycin (mTOR), a central growth controller, on the osmotic stress response. Our results showed that mammalian cells exposed to moderate hypertonicity maintained active mTOR, which was required to sustain their cell size and proliferative capacity. Moreover, mTOR regulated the induction of diverse osmostress response genes, including targets of the tonicity-responsive transcription factor NFAT5 as well as NFAT5-independent genes. Genes sensitive to mTOR-included regulators of stress responses, growth and proliferation. Among them, we identified REDD1 and REDD2, which had been previously characterized as mTOR inhibitors in other stress contexts. We observed that mTOR facilitated transcription-permissive conditions for several osmoresponsive genes by enhancing histone H4 acetylation and the recruitment of RNA polymerase II. Altogether, these results reveal a previously unappreciated role of mTOR in regulating transcriptional mechanisms that control gene expression during cellular stress responses.

Description: Abstract The buttressing potential of ice shelves is modulated by changes in sub‐shelf melting, in response to changing ocean conditions. We analyse the temporal variability in sub‐shelf melting using an autonomous phase‐sensitive radio‐echo sounder (ApRES) near the grounding line of the Roi Baudouin Ice Shelf in East Antarctica. When combined with additional oceanographic evidence of seasonal variations in the stratification and the amplification of diurnal tides around the shelf break topography (Gunnerus Bank), the results suggest an intricate mechanism in which topographic waves control the seasonal melt rate variability near the grounding line. This mechanism has not been considered before, and has the potential to enhance local melt rates without advecting different water masses. As topographic waves seem to strengthen in a stratified ocean, the freshening of Antarctic surface water predicted by observations and models is likely to increase future basal melting in this area.

Description: Sea level rise has serious consequences for harbor infrastructure, storm drains and sewer systems, and many other issues. Adapting to sea level rise requires comparing different possible adaptation strategies, comparing the cost of different actions (including no action), and assessing where and at what point in time the chosen strategy should be implemented. All these decisions must be made under considerable uncertainty–in the amount of sea level rise, in the cost and prioritization of adaptation actions, and in the implications of no action. Here we develop two illustrative examples: for Bergen on Norway's west coast and for Esbjerg on the west coast of Denmark, to highlight how technical efforts to understand and quantify uncertainties in hydrologic projections can be coupled with concrete decision-problems framed by the needs of the end-users using statistical formulations. Different components of uncertainty are visualized. We demonstrate the value of uncertainties and show for example that failing to take uncertainty into account can result in the median projected damage costs being an order of magnitude smaller.

Description: BrF can be prepared by reaction of Br 2 and F 2 in various solvents below –100 °C. In solution it is identified by 19 F NMR and Raman spectroscopy. From CH 3 Cl solution a single crystal structure determination of a BrF/CH 3 Cl adduct was obtained. The preparation from BrF 3 and Br 2 at 600 °C also delivers BrF in small amounts. The crystal structure of BrCl comes in an ordered and a disordered variety. The ordered structure is made of Br–Cl ··· Br–Cl chains. Computations suggest that neat BrF crystallizes in a dipol-dipole type polymeric structure rather than a halogen bonded one as in ClF. A possible intermediate along the decomposition pathway into BrF 3 and Br 2 is Br–BrF 2 .

Description: Observations of interstellar pickup ions inside the heliosphere provide an indirect method to access information on the surrounding interstellar medium. The so-called pickup ion focusing cone and pickup ion crescent, which show an imprint of the related longitudinal distribution of interstellar neutrals in form of two overabundances on the down- and upwind side of the sun, are both believed to be aligned along the inflow vector of the interstellar medium. By finding their longitudinal positions, we can give an accurate value for the inflow direction λISM of interstellar matter. For that we performed an epoch analysis of interstellar pickup ions measured by the PLAsma and SupraThermal Ion Composition instrument (PLASTIC) on the Solar TErrestrial RElations Observatory mission (STEREO) and were able to reveal in situ the longitudinal distribution of interstellar He+, O+, and Ne+ pickup ions in the ecliptic plane at 1 AU. The previously accepted values for the inflow direction of interstellar matter in ecliptic longitude, as obtained with Ulysses/GAS (λ = 75.4° ± 0.5°), Prognoz 6 (λ = 74.5° ± 1°), and ACE/SWICS (λ = 74.43° ± 0.33°), are currently debated, especially in view of recent results from the Interstellar Boundary Explorer (IBEX) mission that show an inflow direction of interstellar neutral helium of λ = 79° + 3.0°(−3.5°). Four years of data collected with PLASTIC aboard STEREO A provided statistics sufficient not only to obtain values for the inflow direction of interstellar helium (λCone = 77.4° ± 1.9° and λCrescent = 80.4° ± 5.4°, deduced from an analysis of the He+ focusing cone and crescent, respectively) but also to derive values for the inflow direction of interstellar neon (λCone = 77.4° ± 5.0° and λCrescent = 79.7° ± 2.6°) and oxygen (λCrescent = 78.9° ± 3.1°). Although our values for He+, O+, and Ne+ are consistent with results from ACE, Ulysses, and Prognoz 6, considering the statistical and systematic uncertainties (except λNe,Crescent), they are systematically larger than the previously accepted values of 74.99 ± 0.55° and show a better agreement with the values from IBEX.

Description: Ice rises situated in the ice-shelf belt around Antarctica have a spatially confined flow regime with local ice divides. Beneath the divides, ice stratigraphy often develops arches with amplitudes that record the divide's horizontal residence time andsurface elevation changes. To investigate the evolution of Derwael Ice Rise, Dronning Maud Land, Antarctica, we combine radar and GPS data from three consecutive surveys, with a two-dimensional, full Stokes, thermomechanically-coupled, transient ice-flow model. We find that the surface mass balance (SMB) is higher on the upwind and lower on the downwind slopes. Near the crest, the SMB is anomalously low and causes arches to form in the shallow stratigraphy, observable by radar. In deeper ice, arches are consequently imprinted by both SMB and ice rheology (Raymond effect). The data show how arch amplitudes decrease as along-ridge slope increases, emphasizing that the lateral positioning of radar cross-sections is important for the arch interpretation. Using the model with three rheologies (isotropic with n = 3,4.5 and anisotropic with n = 3), we show that Derwael Ice Rise is close to steady-state, but is best explained using ice anisotropy and moderate thinning. Our preferred, albeit notunique, scenario suggests that the ice divide has existed for at least 5000 years and lowered at approximately 0.03 m a −1 over the last 3400 years. Independent of the specific thinning scenario, our modeling suggests that Derwael Ice Rise has exhibited a local flow regime at least since the Mid-Holocene.