The Pilot Land Data System (PLDS) at the Ames Research Center manages aircraft data in collaboration with an ecosystem research project

The Pilot Land Data System (PLDS) is a data and information system serving NASA-supported investigators in the land science community. The three nodes of the PLDS, one each at the Ames Research Center (ARC), the Goddard Space Flight Center (GSFC) and the Jet Propulsion Laboratory (JPL), cooperate in providing consistent information describing the various data holding in the hardware and software (accessible via network and modem) that provide information about and access to PLDS-held data, which is available for distribution. A major new activity of the PLDS node at the Ames Research Center involves the interaction of the PLDS with an active NASA ecosystem science project, the Oregon Transect Ecosystems Research involves the management of, access to, and distribution of the large volume of widely-varying aircraft data collected by OTTER. The OTTER project, is managed by researchers at the Ames Research Center and Oregon State University. Its principal objective is to estimate major fluxes of carbon, nitrogen, and water of forest ecosystems using an ecosystem process model driven by remote sensing data. Ten researchers at NASA centers and universities are analyzing data for six sites along a temperature-moisture gradient across the western half of central Oregon (called the Oregon Transect). Sensors mounted on six different aircraft have acquired data over the Oregon Transect in support of the OTTER project

Petrology of the Lower Middle Cambrian Langston Formation, North-Central Utah and Southeastern Idaho

The Lower Middle Cambrian Langson Formation was studied in the xi Bear River Range of north-central Utah and southeasternmost Idaho and the Wellsville Mountains of north-central Utah. The depositional textures and sedimentary structures preserved within the rocks were compared with characteristics of similar modern sediments and ancient rock to determine environments of deposition, paleogeography, diagenetic alteration and pattern of dolomitization. The rocks of the Langston Formation were divided into eleven different rock types. These eleven rock types were formed within four recognizable lithofacies: 1) upper peritidal; 2) inner carbonate shelf; 3) inner clastic shelf; and 4) outer clastic shelf. The general depositional environment is inferred to have been a shall ow subtidal to subaerial carbonate shoal complex. Clastic sediments from the east and north or northwest periodically prograded over the carbonate complex during times of relatively slow subsidence. The deposition of the Langston Formation mudrocks and carbonates occurred during the first Cambrian grand cycle. Eogenetic diagenetic features include birdseye structures, relict evaporite structures, fibrous rim cement, compaction, and the begining of dolomitization. Mesogenetic diagenesis is characterized by dolomitization and pressure solution. Telogenetic diagenesis is limited to fracturing and calcite infilling. Dolomitization is believed to have resulted mainly from downward reflux of hypersaline brines, as indicated by relict evaporite structures, zoned dolomite rhombs, and a general association of dolomite with upper peritidal facies. The hypersaline brines formed in the upper peritidal environment, and percolated downward through underlying porous sediments. The greater density of the hypersaline brines displaced less-dense interstitial fluids. These brines were periodically diluted by normal marine water or fresh water

Further elucidating the steroid isomerisation reaction mechanism of GSTA3-3

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2017.Glutathione S-transferase A3-3 is the most catalytically efficient steroid isomerase enzyme known in humans, transforming Δ5-androstene-3-17-dione into Δ4-androstene-3-17-dione. Though its mechanism of action remains unsolved. GSTA3-3 catalyses this reaction with at least ten-fold greater efficiency than GSTA1-1, its closest competitor in the Alpha class of GSTs. In order to examine the differences between Alpha class GSTs and to better elucidate the mechanism of GSTA3-3 the roles of Tyr9 and Arg15 were examined. Tyr9 is the major catalytic residue of Alpha class GSTs and Arg15 is proposed to be catalytically important to GSTA3-3 but never before experimentally examined. While the structure and stability of the Alpha class enzymes are highly comparable, subtle differences at the G-site of the enzymes account for GSTA3-3 having a ten-fold greater affinity for the substrate GSH. Y9F and R15L mutations, singly or together, have no effect on the structure and stability of GSTA3-3 (the same effect they have on GSTA1-1) despite the R15L mutation removing an interdomain salt-bridge at the active site. Hydrogen-deuterium exchange mass spectrometry also revealed that neither mutation had a significant effect on the conformational dynamics of GSTA3-3. The R15L and Y9F mutations are equally important to the specific activity of the steroid isomerase reaction; however, Arg15 is more important for lowering the pKa of GSH. Lowering the pKa of GSH being how GSTs catalyse their reactions. This suggests an additional role for Tyr9, with an important mechanistic implication. Factoring in the inability to detect an intermediate during the reaction, all data are in agreement with the mechanism being concerted and that Tyr9 acts as a proton shuttle. Additionally, there is evidence to suggest that Arg15 is integral to allowing GSTA3-3 to differentiate between Δ5-androstene-3-17-dione and Δ4-androstene-3-17-dione, indicating that Arg15 is a more important active-site residue than previously recognized.LG201