21 research outputs found
Simulation model of the F/A-18 high angle-of-attack research vehicle utilized for the design of advanced control laws
The 'f18harv' six degree-of-freedom nonlinear batch simulation used to support research in advanced control laws and flight dynamics issues as part of NASA's High Alpha Technology Program is described in this report. This simulation models an F/A-18 airplane modified to incorporate a multi-axis thrust-vectoring system for augmented pitch and yaw control power and actuated forebody strakes for enhanced aerodynamic yaw control power. The modified configuration is known as the High Alpha Research Vehicle (HARV). The 'f18harv' simulation was an outgrowth of the 'f18bas' simulation which modeled the basic F/A-18 with a preliminary version of a thrust-vectoring system designed for the HARV. The preliminary version consisted of two thrust-vectoring vanes per engine nozzle compared with the three vanes per engine actually employed on the F/A-18 HARV. The modeled flight envelope is extensive in that the aerodynamic database covers an angle-of-attack range of -10 degrees to +90 degrees, sideslip range of -20 degrees to +20 degrees, a Mach Number range between 0.0 and 2.0, and an altitude range between 0 and 60,000 feet
The Effects Of Benzodiazepine (Valium) On Permeability Of Language Ego Boundaries 1
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98333/1/j.1467-1770.1980.tb00323.x.pd
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Winter and Summer Home Ranges of American White Pelicans (\u3ci\u3ePelecanus erythrorhynchos\u3c/i\u3e) Captured at Loafing Sites in the Southeastern United States
Satellite telemetry was used to investigate summer and winter home ranges for resident and migrant American White Pelicans (Pelecanus erythrorhynchos) captured in the southeastern United States between 2002 and 2007. Home range utilization distributions were calculated using 50% and 95% kernel density estimators with the plug-in bandwidth selector. Mean summer home ranges (95%) varied from 177 to 4,710 km2 and mean winter home ranges (95%) ranged from 185 to 916 km2. Mean 50% and 95% home ranges of adult American White Pelicans during summer tended to be larger than those during winter, whereas mean 50% and 95% home ranges of immature pelicans during summer tended to be smaller than those during winter. Home ranges for all American White Pelicans encompassed the latitude range of 24°-55° N, including wintering, stop over, and nesting habitat. These data provide baseline movement and home range data for future studies of American White Pelican ecology
Informal Virtual Town Hall Video_April 9, 2020
Video of University of Maine President Joan Ferrini-Mundy\u27s virtual town hall meeting to discuss issues with the University of Maine community relating to the COVID-19 pandemic. Joining President Ferrini-Mundy were Interim Provost Faye Gilbert; Vice Presidents Robert Dana, Chris Lindstrom and Kody Varahramyan; Head of Campus Daniel Qualls; Dean Fred Servello; Chief Business Officer Claire Strickland; and Chief of Staff Kimberly Whitehead. Faculty Senate President David Townsend moderated the session.
Also, includes email message and screenshot of webpage regarding the town hall
Transport of Europium Colloids in Vadose Zone Lysimeters at the Semiarid Hanford Site
The objective of this study was to quantify transport
of Eu colloids
in the vadose zone at the semiarid Hanford site. Eu-hydroxy-carbonate
colloids, Eu(OH)(CO<sub>3</sub>), were applied to the surface of field
lysimeters, and migration of the colloids through the sediments was
monitored using wick samplers. The lysimeters were exposed to natural
precipitation (145–231 mm/year) or artificial irrigation (124–348
mm/year). Wick outflow was analyzed for Eu concentrations, supplemented
by electron microscopy and energy-dispersive X-ray analysis. Small
amounts of Eu colloids (<1%) were detected in the deepest wick
sampler (2.14 m depth) 2.5 months after application and cumulative
precipitation of only 20 mm. We observed rapid transport of Eu colloids
under both natural precipitation and artificial irrigation; that is,
the leading edge of the Eu colloids moved at a velocity of 3 cm/day
within the first 2 months after application. Episodic infiltration
(e.g., Chinook snowmelt events) caused peaks of Eu in the wick outflow.
While a fraction of Eu moved consistent with long-term recharge estimates
at the site, the main mass of Eu remained in the top 30 cm of the
sediments. This study illustrates that, under field conditions, near-surface
colloid mobilization and transport occurred in Hanford sediments
Rab11 Is Required for Membrane Trafficking and Actomyosin Ring Constriction in Meiotic Cytokinesis of Drosophila Males
Rab11 is a small GTPase that regulates several aspects of vesicular trafficking. Here, we show that Rab11 accumulates at the cleavage furrow of Drosophila spermatocytes and that it is essential for cytokinesis. Mutant spermatocytes form regular actomyosin rings, but these rings fail to constrict to completion, leading to cytokinesis failures. rab11 spermatocytes also exhibit an abnormal accumulation of Golgi-derived vesicles at the telophase equator, suggesting a defect in membrane–vesicle fusion. These cytokinesis phenotypes are identical to those elicited by mutations in giotto (gio) and four wheel drive (fwd) that encode a phosphatidylinositol transfer protein and a phosphatidylinositol 4-kinase, respectively. Double mutant analysis and immunostaining for Gio and Rab11 indicated that gio, fwd, and rab11 function in the same cytokinetic pathway, with Gio and Fwd acting upstream of Rab11. We propose that Gio and Fwd mediate Rab11 recruitment at the cleavage furrow and that Rab11 facilitates targeted membrane delivery to the advancing furrow