AirSWOT InSAR Mapping of Surface Water Elevations and Hydraulic Gradients Across the Yukon Flats Basin, Alaska

AirSWOT, an experimental airborne Ka-band interferometric synthetic aperture radar, was developed for hydrologic research and validation of the forthcoming Surface Water and Ocean Topography (SWOT) satellite mission (to be launched in 2021). AirSWOT and SWOT aim to improve understanding of surface water processes by mapping water surface elevation (WSE) and water surface slope (WSS) in rivers, lakes, and wetlands. However, the utility of AirSWOT for these purposes remains largely unexamined. We present the first investigation of AirSWOT WSE and WSS surveys over complex, low-relief, wetland-river hydrologic environments, including (1) a field-validated assessment of AirSWOT WSE and WSS precisions for lakes and rivers in the Yukon Flats Basin, an Arctic-Boreal wetland complex in eastern interior Alaska; (2) improved scientific understanding of surface water flow gradients and the influence of subsurface permafrost; and (3) recommendations for improving AirSWOT precisions in future scientific and SWOT validation campaigns. AirSWOT quantifies WSE with an RMSE of 8 and 15 cm in 1 and 0.0625 km2 river reaches, respectively, and 21 cm in lakes. This indicates good utility for studying hydrologic flux, WSS, geomorphic processes, and coupled surface/subsurface hydrology in permafrost environments. This also suggests that AirSWOT supplies sufficient precision for validating SWOT WSE and WSS over rivers, but not lakes. However, improvements in sensor calibration and flight experiment design may improve precisions in future deployments as may modifications to data processing. We conclude that AirSWOT is a useful tool for bridging the gap between field observations and forthcoming global SWOT satellite products

Psychosocial, socio-cultural, and environmental influences on mental health help-seeking among African-American men

http://dx.doi.org/10.1016/j.jomh.2012.03.00

Photonic molecules and spectral engineering

This chapter reviews the fundamental optical properties and applications of pho-tonic molecules (PMs) - photonic structures formed by electromagnetic coupling of two or more optical microcavities (photonic atoms). Controllable interaction between light and matter in photonic atoms can be further modified and en-hanced by the manipulation of their mutual coupling. Mechanical and optical tunability of PMs not only adds new functionalities to microcavity-based optical components but also paves the way for their use as testbeds for the exploration of novel physical regimes in atomic physics and quantum optics. Theoretical studies carried on for over a decade yielded novel PM designs that make possible lowering thresholds of semiconductor microlasers, producing directional light emission, achieving optically-induced transparency, and enhancing sensitivity of microcavity-based bio-, stress- and rotation-sensors. Recent advances in material science and nano-fabrication techniques make possible the realization of optimally-tuned PMs for cavity quantum electrodynamic experiments, classical and quantum information processing, and sensing.Comment: A review book chapter: 29 pages, 19 figure

Phosphoryl transfer and calcium ion occlusion in the calcium pump

A tight coupling between adenosine triphosphate ATP hydrolysis and vectorial ion transport has to be maintained by ATP consuming ion pumps. We report two crystal structures of Ca2 bound sarco endo plasmic reticulum Ca2 adenosine triphosphatase SERCA at 2.6 and 2.9 angstrom resolution in complex with i a nonhydrolyzable ATP analog [adenosine amp; 946; amp; 947; methylene triphosphate] and ii adenosine diphosphate plus aluminum fluoride. SERCA reacts with ATP by an associative mechanism mediated by two Mg2 ions to form an aspartyl phosphorylated intermediate state Ca2 E1 amp; 8764;P . The conformational changes that accompany the reaction with ATP pull the transmembrane helices 1 and 2 and close a cytosolic entrance for Ca2 , thereby preventing backflow before Ca2 is released on the other side of the membran

Modulatory and Catalytic Modes of ATP Binding by the Calcium Pump

We present crystal structures of the calcium free E2 state of the sarcoplasmic reticulum Ca2 ATPase, stabilized by the inhibitor thapsigargin and the ATP analog AMPPCP. The structures allow us to describe the ATP binding site in a modulatory mode uncoupled from the Asp351 phosphorylation site. The Glu439 side chain interacts with AMPPCP via an Mg2 ion in accordance with previous Fe2 cleavage studies implicating this residue in the ATPase cycle and in magnesium binding. Functional data on Ca2 mediated activation indicate that the crystallized state represents an initial stage of ATP modulated deprotonation of E2, preceding the binding of Ca2 ions in the membrane from the cytoplasmic side. We propose a mechanism of Ca2 activation of phosphorylation leading directly from the compact E2 ATP form to the Ca2E1 ATP state. In addition, a role of Glu439 in ATP modulation of other steps of the functional cycle is suggeste

Natural Products as Starting Materials for Development of Second Generation Serca Inhibitors Targeted Towards Prostate Cancer Cells

An analysis of the binding of the 8 O N tert butoxycarbonyl 12 aminododecanoyl derivative of 8 O debutanoylthapsigargin to the target molecule, the SERCA pump, has revealed the importance of the length and flexibility of the side chain attached to O 8. Based on the analysis a series of analogues to the 2 unsubstituted analogue trilobolide has been constructed and shown to be equipotent with thapsigargin as SERCA inhibitors. Only the 12 Boc aminododecaonoyl derivative, however, was found to be apoptoti