Radiochemical studies of mercury and its ions in dilute solutions

The behavior of the mercurous ion has been studied in dilute aqueous solutions. The ion was found to be unstable toward dismutation

The Flux Ratio Method for Determining the Dust Attenuation of Starburst Galaxies

The presence of dust in starburst galaxies complicates the study of their stellar populations as the dust's effects are similar to those associated with changes in the galaxies' stellar age and metallicity. This degeneracy can be overcome for starburst galaxies if UV/optical/near-infrared observations are combined with far-infrared observations. We present the calibration of the flux ratio method for calculating the dust attenuation at a particular wavelength, Att(\lambda), based on the measurement of F(IR)/F(\lambda) flux ratio. Our calibration is based on spectral energy distributions (SEDs) from the PEGASE stellar evolutionary synthesis model and the effects of dust (absorption and scattering) as calculated from our Monte Carlo radiative transfer model. We tested the attenuations predicted from this method for the Balmer emission lines of a sample starburst galaxies against those calculated using radio observations and found good agreement. The UV attenuation curves for a handful of starburst galaxies were calculated using the flux ratio method, and they compare favorably with past work. The relationship between Att(\lambda) and F(IR)/F(\lambda) is almost completely independent of the assumed dust properties (grain type, distribution, and clumpiness). For the UV, the relationship is also independent of the assumed stellar properties (age, metallicity, etc) accept for the case of very old burst populations. However at longer wavelengths, the relationship is dependent on the assumed stellar properties.Comment: accepted by the ApJ, 18 pages, color figures, b/w version at http://mips.as.arizona.edu/~kgordon/papers/fr_method.htm

The Trouble with "Articulatory" Pauses

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The historical provenance of a minimum cut-off point (of about 0.25 sec) for pauses in temporal analyses of speech production is associated with Goldman-Eisler's usage. Her rationale was the predominance of articulatory pauses at lengths shorter than 0.25 sec. Both phonotactic facts and empirical analysis of several corpora of readings disconfirm this predominance with respect to pauses 0.13-0.25 sec in length. The vast majority of these pauses are found to be psychological; they are determined by syntax, punctuation, rhetorical and expressive emphasis, poetic format, and stylistic pecularities

Development of a Construction Sub-Sector Embodied Energy Hybrid Analysis

Embodied energy analysis is used to evaluate the total energy consumed by any product during all the stages leading up to its manufacture and delivery and can also be used to determine the energy-related environmental impacts such as CO2 emissions of buildings and other built infrastructure. In the wake of increase global awareness on climate change and the strong link between global warming and CO2 emissions, the role of new and improved analytical models to evaluate the energy embodied in products and its associated environmental impacts therefore takes an important role in environmental research studies. The development of a new hybrid embodied energy analysis model which methodologically improves the accuracy of the energy intensity of the construction sector is presented in this paper. This hybrid methodology is applied to four built infrastructure and their respective energy intensities determined. The four construction projects are; a bridge and three different building types. The building types are- a 3-bedroom terrace house, a 3-bedroom semi-detached house and a 4 bedroom detached house all in Dublin, Ireland. The bridge is for a railway line spanning Cork-to-Midleton in County Cork, Ireland. A variability and uncertainty analysis termed applicability error is carried out to determine the inaccuracy in using the sectoral or average construction sector energy intensity rather than the sub-sectoral energy intensities

Time-based vertex reconstruction in the Compact Muon Solenoid

The Phase-II upgrades to the Large Hadron Collider will introduce a variety of new measurement devices to the CMS, including the High-Granularity Calorimeter (HGCAL). The increase in luminosity from these upgrades will also have the undesired side effect of vastly increasing pileup to a level at which the current machine learning vertex reconstruction (vertexing) algorithms cease to be effective. This will necessitate the development of further vertexing algorithms. Using high precision timing measurements from simulated events in the HGCAL, we design a vertex reconstruction algorithm that requires only the spatiotemporal arrival coordinates to reconstruct the interaction vertex of a collision with sub-millimeter resolution. We also analyse how particle energy and simulated time smearing affect this resolution and we apply this algorithm to more realistic H->γγ sets. To do this, we implement a set of filters to remove poorly-reconstructed events and introduce a new algorithm capable of reconstructing interaction vertices given the pointing data and arrival data of a single cluster. Progress on this work was ultimately hindered by extensive errors in the clustering algorithms used the generation of the datasets; should these errors be resolved, further work would include integration with tracker information and the application of these algorithms to high-pileup scenarios and QCD jets

Can an Optical Plankton Counter Produce Reasonable Estimates of Zooplankton Abundance and Biovolume in Water With High Detritus?

The Optical Plankton Counter (OPC) has been used in oceanic and fresh waters to estimate zooplankton abundance and biovolume. However, it is not clear whether the OPC can produce accurate estimates of zooplankton abundance and biovolume in waters with high detritus. In order to test the capability of the OPC to estimate zooplankton abundance and biovolume in Chesapeake Bay, two sets of laboratory experiments were conducted using water with high detritus concentrations collected from the upper Choptank estuary of Chesapeake Bay and laboratory cultured Artemia. Our results suggest that the OPC is able to produce accurate estimates of zooplankton biovolume after correcting for the influence of background detritus in all the detritus concentrations used, but accurate estimates of zooplankton abundance only in water with background detritus \u3c100 particles l-1. The relationship between light attenuation and OPC background particle concentrations provides a useful way to estimate OPC background particle concentrations when direct OPC background particle measurements are not available. Light attenuation corrected OPC particle abundance and particle volume gave accurate estimates of zooplankton abundance and biovolume. However, the accuracy of the corrected OPC measurements by the estimated background particle concentrations was not as high as the corrected OPC measurements by the direct background particle measurements

Ultraviolet Imaging of the Globular Cluster 47 Tucanae

We have used the Ultraviolet Imaging Telescope to obtain deep far-UV (1620 Angstrom), 40' diameter images of the prototypical metal-rich globular cluster 47 Tucanae. We find a population of about 20 hot (Teff > 9000 K) objects near or above the predicted UV luminosity of the hot horizontal branch (HB) and lying within two half-light radii of the cluster center. We believe these are normal hot HB or post-HB objects rather than interacting binaries or blue stragglers. IUE spectra of two are consistent with post-HB phases. These observations, and recent HST photometry of two other metal-rich clusters, demonstrate that populations with rich, cool HB's can nonetheless produce hot HB and post-HB stars. The cluster center also contains an unusual diffuse far-UV source which is more extended than its V-band light. It is possible that this is associated with an intracluster medium, for which there was earlier infrared and X-ray evidence, and is produced by C IV emission or scattered light from grains.Comment: 13 pages AASLaTeX including one postscript figure and one bitmapped image, JPEG format. Submitted to the Astronomical Jorunal. Full Postscript version available at http://www.astro.virginia.edu/~bd4r