Gravity gradient boom stabilization system for the Applications Technology Satellite /ATS-E/, volume 1 Final report

Gravity gradient boom stabilization system for ATS

Circum-Arctic mantle structure and long-wavelength topography since the Jurassic

The circum-Arctic is one of the most tectonically complex regions of the world, shaped by a history of ocean basin opening and closure since the Early Jurassic. The region is characterized by contemporaneous large-scale Cenozoic exhumation extending from Alaska to the Atlantic, but its driving force is unknown. We show that the mantle flow associated with subducted slabs of the South Anuyi, Mongol-Okhotsk, and Panthalassa oceans have imparted long-wavelength deflection on overriding plates. We identify the Jurassic-Cretaceous South Anuyi slab under present-day Greenland in seismic tomography and numerical mantle flow models. Under North America, we propose the “Farallon” slab results from Andean-style ocean-continent convergence around ~30°N and from a combination of ocean-continent and intraoceanic subduction north of 50°N. We compute circum-Arctic dynamic topography through time from subduction-driven convection models and find that slabs have imparted on average <1–16 m/Myr of dynamic subsidence across the region from at least 170 Ma to ~50 Ma. With the exception of Siberia, the main phase of circum-Arctic dynamic subsidence has been followed either by slowed subsidence or by uplift of <1–6 m/Myr on average to present day. Comparing these results to geological inferences suggest that subduction-driven dynamic topography can account for rapid Middle to Late Jurassic subsidence in the Slave Craton and North Slope (respectively, <15 and 21 m/Myr, between 170 and 130 Ma) and for dynamic subsidence (<7 m/Myr, ~170–50 Ma) followed by dynamic uplift (<6 m/Myr since 50 Ma) of the Barents Sea region. Combining detailed kinematic reconstructions with geodynamic modeling and key geological observations constitutes a powerful tool to investigate the origin of vertical motion in remote regions

A pantothenate suxotroph of BCG rxpressing Gag confers enhanced HIV-specific immunogenicity compared to wildtype and perfingolysin expressing strains

In tuberculosis vaccine studies, perfingolysin expressing strains (pfo) of recombinant Mycobacterium bovis (rBCG) have been shown to enhance immunogenicity as compared to wildtype strains whilst pantothenate auxotrophic strains (ΔpanCD) have been shown to be safer and more immunogenic. Our group has recently shown that rBCGΔpanCD expressing HIV-1 Gag is more immunogenic than the wildtype Pasteur strain of BCG in the murine model. In this study, a wild type strain, a ΔpanCDstrain, a pfo strain and a ΔpanCD strain expressing perfringolysin (ΔpanCDpfo) of Danish BCG were used as vectors to express HIV-1 subtype C Gag. Gag specific immune responses induced by a prime with each rBCG-Gag vaccine and boost with modified vaccinia Ankara (MVA) were compared

Miocene drainage reversal of the Amazon River driven by plate–mantle interaction

Northern South America experienced significant changes in drainage patterns during the opening of the South Atlantic Ocean. Disappearance of a mega-wetland in the western Amazonian basins was followed by the formation of the eastward-draining Amazon River, which has been attributed to Andean uplift. However, South America’s westward motion over cold, dense subducted slabs implies that regional subsidence and uplift east of the Andes may have been driven by mantle convection. Here we use a coupled model of mantle convection and plate kinematics to show that dynamic subsidence of up to 40 m Myr^(−1) initially formed the Amazonian mega-wetland. In our model, the sustained westward motion of continental South America over subducted slabs resulted in rebound of the Amazonian mega-wetland region at rates of up to 40 m Myr^(−1) after 30 million years ago, paired with continued subsidence of the eastern Amazonian sedimentary basins at 10–20 m Myr^(−1). The resulting progressive tilt of northern South America to the east enabled the establishment of the Amazon River, suggesting that mantle convection can profoundly affect the evolution of continental drainage systems