Statement of Thomas R. Donahue Before the Commission on the Future of Worker-Management Relations

Includes recommendations to the Commission concerning changes in the National Labor Relations Act.Testimony_Donohue_090894.pdf: 177 downloads, before Oct. 1, 2020

Analysis of OGO-6 observations of the 0 I 5577A tropical nightglow

Atomic oxygen green line data from the horizon scanning photometer on OGO-6 was examined. Unfolding the satellite data from the tropical F-region yields altitude and latitude variations of the O(1S) emissions. The spatial variations of the tropical F-region electron density are then calculated by assuming dissociative recombination and using a model atmosphere. Where comparisons to ground-based data are possible the results are good. Thus, the satellite observations constitute a form of topside sounding of the ionosphere below the F-peak and provide synoptic data about this portion of the ionsphere otherwise impractical to obtain

Venus methane and water

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94590/1/grl6638.pd

Temperatures in a runaway greenhouse on the evolving Venus: implications for water loss

Recent work has established that Venus once had at least 100 times its present complement of outgassed water. An original complement of water comparable to the earth's is not inconsistent with our present knowledge (and is worthy of consideration since it involves no special assumptions concerning the differences in origin of the two planets). We use a one-dimensional calculation to investigate temperatures in the "runaway greenhouse" which may have ensued if Venus once had more than a few percent of the earth's water complement. We find that the atmosphere must exhibit an unusual structure, with condensation and presumably cloud formation taking place at high altitudes, while deep in the atmosphere the gas is strongly unsaturated with respect to water vapour. The necessity of including clouds introduces considerable uncertainty into the calculation of surface temperatures. However, for certain reasonable values of the cloud parameters, very high temperatures can be sustained, approaching the temperature of the basalt solidus. We speculate that such high temperatures may have promoted water-rock reactions, releasing free hydrogen and "burying" oxygen. A plastic or molten surface could have promoted rapid exposure of fresh rock, significantly easing the problem of disposing of the oxygen released by the dissociation of water.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24845/1/0000271.pd

A low-temperature origin for the planetesimals that formed Jupiter

The four giant planets in the Solar System have abundances of 'metals' (elements heavier than helium), relative to hydrogen, that are much higher than observed in the Sun. In order to explain this, all models for the formation of these planets rely on an influx of solid planetesimals(17). It is generally assumed that these planetesimals were similar, if not identical, to the comets from the Oort cloud that we see today. Comets that formed in the region of the giant planets should not have contained much neon, argon and nitrogen, because the temperatures were too high for these volatile gases to be trapped effectively in ice. This means that the abundances of those elements on the giant planets should be approximately solar. Here we show that argon, krypton and xenon in Jupiter's atmosphere are enriched to the same extent as the other heavy elements, which suggests that the planetesimals carrying these elements must have formed at temperatures lower than predicted by present models of giant-planet formation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62913/1/402269a0.pd

Effects of polylinker uATGs on the function of grass HKT1 transporters expressed in yeast cells

HvHKT1 mediates K+ or Na+ uniport in yeast cells if the expression promoter is joined directly to the HvHKT1 cDNA, and Na+-K+ symport if a 59-nt polylinker is inserted. Our results show that three ATG triplets in the polylinker decreased the synthesis of the transporter and that the lower amount of transporter caused the functional change. With the rice HKT1 cDNA, the 59-nt polylinker changed the mode of Na+ uptake from K+-insensitive to K+-inhibitable. These two modes of Na+ uptake also occurred in rice plant

The Extended Blue Continuum and Line Emission around the Central Radio Galaxy in Abell 2597

We present results from detailed imaging of the centrally dominant radio elliptical galaxy in the cooling flow cluster Abell 2597, using data obtained with the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST). This object is one of the archetypal "blue-lobed" cooling flow radio elliptical galaxies, also displaying a luminous emission-line nebula, a compact radio source, and a significant dust lane and evidence of molecular gas in its center. We show that the radio source is surrounded by a complex network of emission-line filaments, some of which display a close spatial association with the outer boundary of the radio lobes. We present a detailed analysis of the physical properties of ionized and neutral gas associated with the radio lobes, and show that their properties are strongly suggestive of direct interactions between the radio plasma and ambient gas. We resolve the blue continuum emission into a series of knots and clumps, and present evidence that these are most likely due to regions of recent star formation. We investigate several possible triggering mechanisms for the star formation, including direct interactions with the radio source, filaments condensing from the cooling flow, or the result of an interaction with a gas-rich galaxy, which may also have been responsible for fueling the active nucleus. We propose that the properties of the source are plausibly explained in terms of accretion of gas by the cD during an interaction with a gas-rich galaxy, which combined with the fact that this object is located at the center of a dense, high-pressure ICM can account for the high rates of star formation and the strong confinement of the radio source.Comment: Astrophysical Journal, in press, 34 pages, includes 6 PostScript figures. Latex format, uses aaspp4.sty and epsf.sty file

Ground-based measurements of O1D and the H2O production rate from comets

Ground-based high spectral resolution measurements of Comet Halley in the 6300.3 A spectral region establish this technique as a powerful and low cost method for determining cometary H2O production rates. A model on the line profile to be expected from the O1D coma emission indicates that ground-based observations with fields of view on the comet of about 1 x 105 km measure profiles characteristic of O1D from the H2O parent. As the field of view increases, the signature of more energetic O1D ejected by CO2 and CO photolysis may become evident in the wings of the 6300.3 A line profile. The width of the 6300.3 A O1D profile is found to be equal to the ejection speed of O1D following H2O photolysis for fields of view to 1 x 106 km. Halley observations show that cometary NH2 (0,8,0) emissions do not contaminate the cometary O1D signature when the spectral resolution is 2O production rates determined by scaling the measured O1D production rates according to the H2O photolysis branching ratio are in good agreement with other measurements. Minor upgrades in the tracking and spectral resolution capabilities of observatories now dedicated to measurements of the terrestrial airglow would be useful for expansion of the high resolution cometary O1D data base - to include comets that come with less fanfare than did Halley.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28149/1/0000601.pd

Strong molecular hydrogen emission and kinematics of the multiphase gas in radio galaxies with fast jet-driven outflows

Observations of ionized and neutral gas outflows in radio-galaxies (RGs) suggest that AGN radio jet feedback has a galaxy-scale impact on the host ISM, but it is still unclear how the molecular gas is affected. We present deep Spitzer IRS spectroscopy of 8 RGs that show fast HI outflows. All of these HI-outflow RGs have bright H2 mid-IR lines that cannot be accounted for by UV or X-ray heating. This suggests that the radio jet, which drives the HI outflow, is also responsible for the shock-excitation of the warm H2 gas. In addition, the warm H2 gas does not share the kinematics of the ionized/neutral gas. The mid-IR ionized gas lines are systematically broader than the H2 lines, which are resolved by the IRS (with FWHM up to 900km/s) in 60% of the detected H2 lines. In 5 sources, the NeII line, and to a lesser extent the NeIII and NeV lines, exhibit blue-shifted wings (up to -900km/s with respect to the systemic velocity) that match the kinematics of the outflowing HI or ionized gas. The H2 lines do not show broad wings, except tentative detections in 3 sources. This shows that, contrary to the HI gas, the H2 gas is inefficiently coupled to the AGN jet-driven outflow of ionized gas. While the dissipation of a small fraction (<10%) of the jet kinetic power can explain the dynamical heating of the molecular gas, our data show that the bulk of the warm molecular gas is not expelled from these galaxies.Comment: 26 pages, 15 figures, Accepted for ublication in Ap