Velocity Model for CO2 Sequestration in the Southeastern United States Atlantic Continental Margin

The sequestration of carbon dioxide (CO2) is emerging as a major player in offsetting anthropogenic greenhouse gas emissions. With 40% of the United States’ anthropogenic CO2 emissions originating in the southeast, characterizing potential CO2 sequestration sites is vital to reducing the United States’ emissions. The overall goal of this research project, funded by the Department of Energy, is to estimate the CO2 storage potential for the Southeastern United States Atlantic Continental Margin. Previous studies find storage potential in the Atlantic continental margin. Up to 16 Gt and 175 Gt of storage potential are estimated for the Upper Cretaceous and Lower Cretaceous formations, respectively. Considering 5.2 Gt of CO2 were emitted by the United States in 2016, substantial storage potential is present in the Southeastern United States Atlantic Continental Margin. Stratigraphic units were picked in two-way-time depth and were converted to depths in feet. Seismic reflection horizons were extrapolated using well log data from the COST GE-1 well. An interpolated seismic section was created using these seismic horizons. A velocity model was created using previously published stacking velocities. Semblance analysis was used to pick stacking velocities on common midpoint gathers from selected pre-stack seismic lines. These velocity analysis points were used for quality control of the published stacking velocities. Stacking velocities were converted to interval velocities using Dix conversion. These interval velocities are used to create the velocity model and calculate the depths of stratigraphic units in feet. Using this velocity model, the seismic reflection data can be converted to depth in order to estimate the thickness and storage potential of CO2 reservoirs in the Southeastern United States Atlantic Continental Margin

the climate change issue in Germany 2007-2010

This paper assesses the impact of large events such as the financial crisis in 2008 and the Copenhagen meeting in 2009 on the public attention attributed to the climate change issue and to the related policy discourse in the German press. Based on a quantitative content analysis of the two largest German national quality newspapers, a quasi-experimental approach will be adopted, testing the propositions of “punctuated equilibrium theory” (Baumgartner & Jones 1993) in policy analysis. The paper will also use concepts and approaches in the area of discourse analysis – from qualitative methods to more formal quantitative approaches to the analysis of discourse structures and network relations (Janning et al 2009). Large scale and focusing events such as the economic crisis or the Copenhagen meeting can trigger shifts and changes in the discourse on climate change. Preliminary analysis has shown that the economic crisis produced a kink in the issue-attention cycle, triggering a substantial decrease in public attention as public attention to the economic crisis soared. Moreover, the results indicate that actors have changed their discursive behavior in the light of the economic crisis, entailing changes in the actors’ standing and the frames applied by them to the issue of climate change (Vogt 2009). As natural experiments run short of quantifying causal links between variables, the observed changes in public attention and discursive behavior can at least be explained by qualitative explanatory sketches in which the changes and shifts are traced and interrelated by visual descriptions at various levels

Potent Antibody Protection against an Emerging Alphavirus Threat

Chikungunya virus recently caused large outbreaks world-wide. In this issue of Cell, Fox et al. describe several potently neutralizing antibodies against multiple alphaviruses. The structure of the virus in complex with one of the antibodies reveals the antibody-induced rearrangement and crosslinking of the viral surface proteins that result in neutralization

Ganglioside headgroups decrease lipid order in reconstituted phosphatidylcholine liposomes

AbstractThe effect of oligosaccharide carrying lipids on membrane fluidity has been investigated. Gangliosides GM1 and GQ1 were reconstituted into phosphatidylcholine bilayer membranes at low concentrations ( < 5 mol%). A strong fluidizing effect was observed leading to a suppression of the phase transition temperature. This was most pronounced with highly sialylated gangliosides. Ca2+ reverses the effect due to phase separation phenomena. We assume a hydrophilic lipid-lipid interaction in accordance with previously studied glycoprotein-lipid interactions

Impact of hot exozodiacal dust on the polarimetric analysis of close-in exoplanets

Hot exozodiacal dust (HEZD) found around main-sequence stars through interferometric observations in the photometric bands H to L is located close to the dust sublimation radius, potentially at orbital radii comparable to those of close-in exoplanets. Consequently, HEZD has a potential influence on the analysis of the scattered-light polarization of close-in exoplanets and vice versa. We analyze the impact of HEZD on the polarimetric characterization of close-in exoplanets. This study is motivated in particular by the recently proven feasibility of exoplanet polarimetry. Applying the 3D Monte Carlo radiative transfer code POLARIS in an extended and optimized version for radiative transfer in exoplanetary atmospheres and an analytical tool for modeling the HEZD, we simulated and compared the polarization characteristics of the wavelength-dependent scattered-light polarization of HEZD and close-in exoplanets. The varied parameters are the planetary phase angle ($0^\circ-180^\circ$), the dust grain radius ($0.02\ \mu$m $- \ 10\ \mu$m), the HEZD mass ($10^{-10}$$\rm{M}_{\oplus}$ $-\ 10^{-8}$$\rm{M}_{\oplus}$), the orbital inclination ($0^\circ-90^\circ$), the composition of the planetary atmosphere (Mie and Rayleigh scattering atmosphere), the orbital radius of the HEZD ($0.02$ au $-\ 0.4$ au), and the planetary orbital radius ($0.01$ au $-\ 0.05$ au). The dust grain radius has the strongest influence on the polarimetric analysis due to its significant impact on the wavelength-dependent polarization characteristics and the total order of magnitude of the scattered-light polarization. In certain scenarios, the scattered-light polarization of the HEZD even exceeds that of the close-in exoplanet.Comment: Accepted for publication in Astronomy \& Astrophysics. 14 pages, 13 figure