71 research outputs found
Proceedings of the NASA First Wake Vortex Dynamic Spacing Workshop
A Government and Industry workshop on wake vortex dynamic spacing systems was conducted on May 13-15, 1997, at the NASA Langley Research Center. The purpose of the workshop was to disclose the status of ongoing NASA wake vortex R&D to the international community and to seek feedback on the direction of future work to assure an optimized research approach. Workshop sessions examined wake vortex characterization and physics, wake sensor technologies, aircraft/wake encounters, terminal area weather characterization and prediction, and wake vortex systems integration and implementation. A final workshop session surveyed the Government and Industry perspectives on the NASA research underway and related international wake vortex activities. This document contains the proceedings of the workshop including the presenters' slides, the discussion following each presentation, the wrap-up panel discussion, and the attendees' evaluation feedback
Numerical Simulation of the Aircraft Wake Vortex Flowfield
The near wake vortex flowfield from a NACA0012 half-wing was simulated using a fully unstructured Navier-Stokes flow solver in three dimensions at a chord Reynolds number of 4.6 million and a Mach number of approximately 0.15. Several simulations were performed to examine the effect of boundary conditions, mesh resolution and turbulence scheme on the formation of wingtip vortex and its downstream propagation. The standard Spalart-Allmaras turbulence model was compared with the Dacles-Mariani and Spalart-Shur corrections for rotation and curvature effects. The simulation results were evaluated using the data from experiment performed at NASA Ames' 32in x 48in low speed wind tunnel
A New Probe of the Planet-Forming Region in T Tauri Disks
We present new observations of the FUV (1100-2200 Angstrom) radiation field
and the near- to mid-IR (3--13.5 micron) spectral energy distribution (SED) of
a sample of T Tauri stars selected on the basis of bright molecular disks (GM
Aur, DM Tau, LkCa15). In each source we find evidence for Ly alpha induced H2
fluorescence and an additional source of FUV continuum emission below 1700
Angstroms. Comparison of the FUV spectra to a model of H2 excitation suggests
that the strong continuum emission is due to electron impact excitation of H2.
The ultimate source of this excitation is likely X-ray irradiation which
creates hot photo-electrons mixed in the molecular layer. Analysis of the SED
of each object finds the presence of inner disk gaps with sizes of a few AU in
each of these young (~1 Myr) stellar systems. We propose that the presence of
strong H2 continuum emission and inner disk clearing are related by the
increased penetration power of high energy photons in gas rich regions with low
grain opacity.Comment: 5 pages, 3 figures, accepted by ApJ Letter
Early Infrared Spectral Development of V1187 Scorpii (Nova Scorpii 2004 No. 2)
We report on an unprecedented infrared time series of spectra of V1187 Sco, a very fast ONeMg nova. The observations covered a 56 day period (2004 August 6-September 30) starting 2 days after the nova's peak brightness. Time evolution of the spectra revealed changing line strengths and profiles on timescales of less than a day to weeks as the nova evolved from early postmaximum to early coronal phases. When our ground-based optical and Spitzer Space Telescope data were combined, the wavelength coverage of 0.38-36 μm allowed an accurate spectral energy distribution to be derived when it was about 6 weeks after outburst. Developing double structure in the He I lines showed them changing from narrow to broad in only a few days. Using the O I lines in combination with the optical spectra, we derived a reddening of E(B - V) = 1.56 ± 0.08 and a distance of 4.9 ± 0.5 kpc. Modeling of the ejected material strongly suggested that it was geometrically thick with ΔR/R = 0.8-0.9 (more of a wind than a shell) and a low filling factor of order a few percent. The line shapes were consistent with a cylindrical jet, bipolar, or spherical Hubble flow expansion with a maximum speed of about -3000 km s-1. The central peak appeared to be more associated with the spherical component, while the two peaks (especially in Hβ) suggested a ring with either a lower velocity component or with its axis inclined to the line of sight
SLC25A51 is a mammalian mitochondrial NAD+ transporter
Mitochondria require nicotinamide adenine dinucleotide (NAD+) to carry out the fundamental processes that fuel respiration and mediate cellular energy transduction. Mitochondrial NAD+ transporters have been identified in yeast and plants1,2, but their existence in mammals remains controversial3,4,5. Here we demonstrate that mammalian mitochondria can take up intact NAD+, and identify SLC25A51 (also known as MCART1)—an essential6,7 mitochondrial protein of previously unknown function—as a mammalian mitochondrial NAD+ transporter. Loss of SLC25A51 decreases mitochondrial—but not whole-cell—NAD+ content, impairs mitochondrial respiration, and blocks the uptake of NAD+ into isolated mitochondria. Conversely, overexpression of SLC25A51 or SLC25A52 (a nearly identical paralogue of SLC25A51) increases mitochondrial NAD+ levels and restores NAD+ uptake into yeast mitochondria lacking endogenous NAD+ transporters. Together, these findings identify SLC25A51 as a mammalian transporter capable of importing NAD+ into mitochondria.acceptedVersio
The "Peer" in "Peer Review"
Gad Perry1, Jaime Bertoluci2, Bruce Bury3, Robert W. Hansen4, Robert Jehle5, John Measey6, Brad R. Moon7, Erin Muths8, and Marco A. L. Zuffi9,* 1 Texas Tech University, Lubbock, TX, USA; Journal of Herpetology. 2 Universidade de Sao Paulo, Brazil; Phyllomedusa. 3 USGS, Corvallis, OR, USA; Herpetological Conservation and Biology. 4 Clovis, CA, USA; Herpetological Review. 5 University of Salford, Greater Manchester, UK; Herpetological Journal. 6 University of the Western Cape, South Africa; African Journal of Herpetology. 7 University of Louisiana at Lafayette, LA, USA; Herpetologica. 8 USGS, Fort Collins, CO, USA; Journal of Herpetology. 9 Museum Natural History, University of Pisa, Italy; Acta Herpetologica
TOI-4641b: An Aligned Warm Jupiter Orbiting a Bright (V=7.5) Rapidly Rotating F-star
We report the discovery of TOI-4641b, a warm Jupiter transiting a rapidly
rotating F-type star with a stellar effective temperature of 6560 K. The planet
has a radius of 0.73 , a mass smaller than 3.87 ,
and a period of 22.09 days. It is orbiting a bright star (V=7.5 mag) on a
circular orbit with a radius and mass of 1.73 and 1.41 .
Follow-up ground-based photometry was obtained using the Tierras Observatory.
Two transits were also observed with the Tillinghast Reflector Echelle
Spectrograph (TRES), revealing the star to have a low projected spin-orbit
angle (= degrees). Such obliquity measurements
for stars with warm Jupiters are relatively few, and may shed light on the
formation of warm Jupiters. Among the known planets orbiting hot and
rapidly-rotating stars, TOI-4641b is one of the longest-period planets to be
thoroughly characterized. Unlike hot Jupiters around hot stars which are more
often misaligned, the warm Jupiter TOI-4641b is found in a well-aligned orbit.
Future exploration of this parameter space can add one more dimension to the
star-planet orbital obliquity distribution that has been well-sampled for hot
Jupiters.Comment: Accepted MNRA
Variability of Disk Emission in Pre-Main Sequence and Related Stars. I. HD 31648 and HD 163296 - Isolated Herbig Ae Stars Driving Herbig-Haro Flows
Infrared photometry and spectroscopy covering a time span of a quarter
century are presented for HD 31648 (MWC 480) and HD 163296 (MWC 275). Both are
isolated Herbig Ae stars that exhibit signs of active accretion, including
driving bipolar flows with embedded Herbig-Haro (HH) objects. HD 163296 was
found to be relatively quiescent photometrically in its inner disk region, with
the exception of a major increase in emitted flux in a broad wavelength region
centered near 3 microns in 2002. In contrast, HD 31648 has exhibited sporadic
changes in the entire 3-13 micron region throughout this span of time. In both
stars the changes in the 1-5 micron flux indicate structural changes in the
region of the disk near the dust sublimation zone, possibly causing its
distance from the star to vary with time. Repeated thermal cycling through this
region will result in the preferential survival of large grains, and an
increase in the degree of crystallinity. The variability observed in these
objects has important consequences for the interpretation of other types of
observations. For example, source variability will compromise models based on
interferometry measurements unless the interferometry observations are
accompanied by nearly-simultaneous photometric data.Comment: 55 pages, 18 figures, 2 tables, Accepted by Ap
Crop Updates 2010 - Farming Systems
This session covers twenty papers from different authors:
Pests and Disease
1. Preserving phosphine for use in Grain Storage Industry, Christopher R Newman, Department of Agriculture and Food
Farming Systems Research
2. Demonstrating the benefits of grazing canola in Western Australia, Jonathan England, Stephen Gherardi and Mohammad Amjad, Department of Agriculture and Food
3. Buloke barley yield when pasture-cropped across subtropical perennial pastures, David Ferris, Department of Agriculture and Food, Phil Ward and Roger Lawes, CSIRO
4. Is pasture cropping viable in WA? Grower perceptions and EverCrop initiatives to evaluate, David Ferris, Tim Wiley, Perry Dolling, Department of Agriculture and Food, Philip Barrett-Lennard, Evergreen farming
5. Best-bet management for dual-purpose canola, John Kirkegaard, Susan Sprague, Hugh Dove and Walter Kelman, CSIRO, Canberra, Peter Hamblin, Agritech Research, Young, NSW
6. Pasture in cropping systems – with and without sheep, Brad Nutt and Angelo Loi, Department of Agriculture and Food
7. Can technology substitute for a lupin break? Wayne Parker, Department of Agriculture and Food
8. Canola row spacing with and without long term stubble retention on a sandy clay loam at Merredin, Glen Riethmuller, Department of Agriculture and Food
9. Impact of stubble retention on water balance and crop yield, Phil Ward1, Ken Flower2,3, Neil Cordingley2 and Shayne Micin1, 1CSIRO, Wembley, Western Australia, 2Western Australian No-Till Farmers Association, 3University of Western Australia
Analysis and Modelling
10. Using POAMA rainfall forecasts for crop management in South-West WA, Senthold Asseng1, Peter McIntosh2,3, Mike Pook2,3, James Risbey2,3, Guomin
Wang3, Oscar Alves3, Ian Foster4, Imma Farre4 and Nirav Khimashia1, 1CSIRO Plant Industry, Perth, 2CSIRO Marine and Atmospheric Research, Hobart, 3Centre for Australian Weather and Climate Research (CAWCR), A partnership between the Australian Bureau of Meteorology and CSIRO, Melbourne, 4Department of Agriculture and Food
11. Adaption to changing climates and variability – results of the Agribusiness Changing Climates regional workshop, Anderson W3, Beard D3, Blake J3, Grieve R1, Lang M3, Lemon J3, McTaggart R3, Gray D3, Price M2 and Stephens D3, 1Roderick Grieve Farm Management Consultants, 2Coffey International P/L, 3Department of Agriculture and Food
12. Farmers’ management of seasonal variability and climate change in WA, DA Beard, DM Gray, P Carmody, Department of Agriculture and Food
13. Is there a value in having a frost forecast for wheat in South-West WA? Imma Farre1, Senthold Asseng2, Ian Foster1 and Doug Abrecht3, 1Department of Agriculture and Food, CSIRO, Floreat, 2CSIRO Plant Industry, Perth
3Department of Agriculture and Food, Centre for Cropping Systems
14. Does buying rainfall pay? Greg Kirk, Planfarm Agricultural Consultants
15. Which region in the WA wheatbelt makes best use of rainfall? Peter Rowe, Bankwest Agribusiness
16. POAMA – the Predictive Ocean-Atmosphere Model for Australia, Guomin Wang and Oscar Alves, Centre for Australian Weather and Climate Research (CAWCR), A partnership between the Australian Bureau of Meteorology and CSIRO, Melbourne
17. Exploring the link between water use efficiency and farm profitability, Cameron Weeks, Planfarm and Peter Tozer, PRT Consulting
Precision Agriculture
18. A plethora of paddock information is available – how does it stack up? Derk Bakker, Department of Agriculture and Food
18. Variable rate prescription mapping for lime inputs based on electromagnetic surveying and deep soil testing, Frank D’Emden, Quenten Knight and Luke Marquis, Precision Agronomics, Australia
19. Trial design and analysis using precision agriculture and farmer’s equipment, Roger Lawes, CSIRO Sustainable Ecosystems, Centre for Environment and Life
Sciences, Floreat
20. Farmer perspectives of precision agriculture in Western Australia: Issues and the way forward, Dr Roger Mandel, Curtin Universit
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