Field Measurements of Terrestrial and Martian Dust Devils

Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types

A Flow Induced Autoimmune Response and Accelerated Senescence of Red Blood Cells in Cardiovascular Devices

Red blood cells (RBCs) passing through heart pumps, prosthetic heart valves and other cardiovascular devices undergo early senescence attributed to non-physiologic forces. We hypothesized that mechanical trauma accelerates aging by deformation of membrane proteins to cause binding of naturally occurring IgG. RBCs isolated from blood of healthy volunteers were exposed to high shear stress in a viscometer or microfluidics channel to mimic mechanical trauma and then incubated with autologous plasma. Increased binding of IgG was observed indicating forces caused conformational changes in a membrane protein exposing an epitope(s), probably the senescent cell antigen of band 3. The binding of immunoglobulin suggests it plays a role in the premature sequestration and phagocytosis of RBCs in the spleen. Measurement of IgG holds promise as a marker foreshadowing complications in cardiovascular patients and as a means to improve the design of medical devices in which RBCs are susceptible to sublethal trauma.Research in this publication was supported by the National Institutes of Health Small Business Innovation Research program under award number R44HL114246 as a subcontract to the University of Oklahoma from VADovations and NIH grant R21HL132286 to DWS and TAS. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

A mobile, phased array Doppler radar for the study of severe convective storms

The article of record as published may be found at http://dx.doi.org/10.1175/2009BAMS2914.1(1999) found after inspecting Weather Surveillance Radar-1988 Doppler (WSR-88D) volume scans that some tornadic vortex signatures descend, whereas others appear in a column simultaneously. Since it takes -4-5 min to complete a volume scan (Crum and Alberty 1993), the latter finding might not hold for shorter time scales: A midlevel (~5 km AGL) vortex advected downward by a downdraft of -20 m s-1 for 4 min will descend ~5 km (i.e., down to the ground); with observations on a 4-5-min time scale, the descent would appear to be simultaneous.This work was supported in part by NSF Grant ATM-0637148 to the University of Oklahoma and contracts to ProSensing from the NAVY SBIR program at the Office of Naval ResearchNSF Grant ATM-063714