Photosynthetic reaction center complexes from heliobacteria

The goal of this project is to understand the early evolutionary development of photosynthesis by examining the properties of reaction centers isolated from certain contemporary organisms that appear to contain the simplest photosynthetic reaction centers. The major focus of this project is the family of newly discovered strictly anaerobic photosynthetic organisms known as Heliobacteria. These organisms are the only known photosynthetic organisms that are grouped with the gram-positive phylum of bacteria. The properties of these reaction centers suggest that they might be the decendants of an ancestor that also gave rise to Photosystem 1 found in oxygen-evolving photosynthetic organisms. Photoactive reaction center-core antenna complexes have been isolated from the photosynthetic bacteria Heliobacillus mobilis and Heliobacterium gestii. The absorption and fluorescence properties of membranes and reaction centers are almost identical, suggesting that a single pigment-protein complex serves as both antenna and reaction center. Experiments in progress include sequence determination of the 48,000 Mr reaction center protein, and evolutionary comparisons with other reaction center proteins

Assimilation of SMOS Retrieved Soil Moisture into the Land Information System

No abstract availabl

Impact of AIRS Thermodynamic Profiles on Precipitation Forecasts for Atmospheric River Cases Affecting the Western United States

No abstract availabl

The thermodynamic dual structure of linear-dissipative driven systems

The spontaneous emergence of dynamical order, such as persistent currents, is sometimes argued to require principles beyond the entropy maximization of the second law of thermodynamics. I show that, for linear dissipation in the Onsager regime, current formation can be driven by exactly the Jaynesian principle of entropy maximization, suitably formulated for extended systems and nonequilibrium boundary conditions. The Legendre dual structure of equilibrium thermodynamics is also preserved, though it requires the admission of current-valued state variables, and their correct incorporation in the entropy

Privilege and Marginality: How Group Identification and Personality Predict Rightâ and Leftâ Wing Political Activism

In two studies, we examine how different processes might underlie the political mobilization of individuals with marginalized versus privileged identities for leftâ wing activism (LWA) versus rightâ wing activism (RWA). In the first study, with a sample of 244 midlife women, we tested the hypotheses that endorsement of system justification beliefs and social identities were direct predictors of political activism, and that system justification beliefs moderated the mobilization of social identities for activism on both the left and the right. We found that system justification predicted RWA only among those who felt close to privileged groups; the parallel reverse effect did not hold for LWA, though rejection of systemâ justifying beliefs was an important direct predictor. In Study 2, we replicated many of these findings with a sample of 113 college students. In addition, we tested and confirmed the hypothesis that LWA is predicted by openness to experience and is unrelated to RWA, but not that openness plays a stronger role among those with marginalized identities. These two studies together support our overall hypothesis that different personality processes are involved with political mobilization of privileged and marginalized individuals on the right and the left.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141967/1/asap12132_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141967/2/asap12132.pd

Electron Capture at Very Small Scattering Angles from Atomic Hydrogen by 25-125-keV Protons

Differential cross sections for electron capture in collisions between protons and hydrogen atoms have been experimentally determined for incident proton energies of 25, 60, and 125 keV in the center-of-mass scattering-angle range of 0-3 mrad. The experimental results compare more favorably with the results of both a multistate and a two-state calculation than with the results of a continuum distorted-wave-approximation calculation. There is no evidence of a Jackson-Schiff-type minimum

Constant amplitude and post-overload fatigue crack growth behavior in PM aluminum alloy AA 8009

A recently developed, rapidly solidified, powder metallurgy, dispersion strengthened aluminum alloy, AA 8009, was fatigue tested at room temperature in lab air. Constant amplitude/constant delta kappa and single spike overload conditions were examined. High fatigue crack growth rates and low crack closure levels compared to typical ingot metallurgy aluminum alloys were observed. It was proposed that minimal crack roughness, crack path deflection, and limited slip reversibility, resulting from ultra-fine microstructure, were responsible for the relatively poor da/dN-delta kappa performance of AA 8009 as compared to that of typical IM aluminum alloys

Momentum-Transfer Scaling in Hydrogen-Isotope Collision Systems

The differential cross sections for excitation of atomic hydrogen isotopes to their n=2 states by proton or deutron impact are found to follow a simple scaling relationship. The momentum-transfer-scaled differential excitation cross sections, for a projectile velocity of 1.26 a.u., produce one differential cross-section curve for all four possible hydrogen-isotope collision systems. The experimental results are in excellent agreement with our Glauber-approximation calculations

Greenland subglacial lakes detected by radar

This is the final version of the article. Available from AGU via the DOI in this record.Subglacial lakes are an established and important component of the basal hydrological system of the Antarctic ice sheets, but none have been reported from Greenland. Here we present airborne radio echo sounder (RES) measurements that provide the first clear evidence for the existence of subglacial lakes in Greenland. Two lakes, with areas ~8 and ~10 km2, are found in the northwest sector of the ice sheet, ~40 km from the ice margin, and below 757 and 809 m of ice, respectively. The setting of the Greenland lakes differs from those of Antarctic subglacial lakes, being beneath relatively thin and cold ice, pointing to a fundamental difference in their nature and genesis. Possibilities that the lakes consist of either ancient saline water in a closed system or are part of a fresh, modern open hydrological system are discussed, with the latter interpretation considered more likely.Funding was provided by NERC grant NE/ H020667. Additional support was provided by NASA grant NNX11AD33G and the G. Unger Vetlesen foundation

Isotope Effect and Momentum-Transfer Scaling in the Elastic-Scattering Differential Cross Sections for Hydrogen-Isotope Collision Systems

A projectile-dependent isotope effect was found for the elastic-scattering differential cross sections in the hydrogen-isotope collision systems. All four differential cross sections lie on a common curve if they are divided by the square of the reduced mass and plotted against momentum transfer. The experimental results are in satisfactory agreement with a simple Glauber-approximation calculation