Oscillator Strengths for B-X, C-X, and E-X Transitions in Carbon Monoxide

Band oscillator strengths for electronic transitions in CO were obtained at the Synchrotron Radiation Center of the University of Wisconsin-Madison. Our focus was on transitions that are observed in interstellar spectra with the Far Ultraviolet Spectroscopic Explorer; these transitions are also important in studies of selective isotope photodissociation where fractionation among isotopomers can occur. Absorption from the ground state (X ^1Sigma^+ v'' = 0) to A ^1Pi (v'= 5), B ^1Sigma^+ (v' = 0, 1), C ^1Sigma^+ (v' = 0, 1), and E ^1Pi (v' = 0) was measured. Fits to the A - X (5, 0) band, whose oscillator strength is well known, yielded the necessary column density and excitation temperature. These parameters were used in a least-squares fit of the observed profiles for the transitions of interest to extract their band oscillator strengths. Our oscillator strengths are in excellent agreement with results from recent experiments using a variety of techniques. This agreement provides the basis for a self-consistent set of f-values at far ultraviolet wavelengths for studies of interstellar (and stellar) CO.Comment: 22 pages, 3 figures, ApJS (in press

The read-across hypothesis and environmental risk assessment of pharmaceuticals

This article is made available through the Brunel Open Access Publishing Fund. Copyright © 2013 American Chemical Society.Pharmaceuticals in the environment have received increased attention over the past decade, as they are ubiquitous in rivers and waterways. Concentrations are in sub-ng to low μg/L, well below acute toxic levels, but there are uncertainties regarding the effects of chronic exposures and there is a need to prioritise which pharmaceuticals may be of concern. The read-across hypothesis stipulates that a drug will have an effect in non-target organisms only if the molecular targets such as receptors and enzymes have been conserved, resulting in a (specific) pharmacological effect only if plasma concentrations are similar to human therapeutic concentrations. If this holds true for different classes of pharmaceuticals, it should be possible to predict the potential environmental impact from information obtained during the drug development process. This paper critically reviews the evidence for read-across, and finds that few studies include plasma concentrations and mode of action based effects. Thus, despite a large number of apparently relevant papers and a general acceptance of the hypothesis, there is an absence of documented evidence. There is a need for large-scale studies to generate robust data for testing the read-across hypothesis and developing predictive models, the only feasible approach to protecting the environment.BBSRC Industrial Partnership Award BB/ I00646X/1 and BBSRC Industrial CASE Partnership Studentship BB/I53257X/1 with AstraZeneca Safety Health and Environment Research Programme

Constraints of the durability of inorganic and organic consolidants for marble

In the present study, 5 different consolidants were tested on 5 different marble varieties preliminarily subjected to artificial weathering, to evaluate their consolidating effectiveness and thermal behavior after consolidation, in terms of residual strain after heating–cooling cycles in dry and wet condition and tendency to bowing. Treatments based on ethyl silicate, with and without a coupling agent to improve the performance on calcitic substrates, exhibited modest increases in cohesion after consolidation, as well as an increase in the thermal expansion coefficient and some residual strain at the end of the cycles. Paraloid B72 caused minor alterations in the pore system and limited increases in ultrasonic velocity, while the so-called “acrylic total impregnation” method led to an almost complete pore filling and significant improvements in cohesion. While the latter samples apparently resisted well to heating–cooling cycles, samples impregnated with Paraloid B72 exhibited progressive collapse of the fabric, likely due to the low glass transition temperature of Paraloid B72. Ammonium phosphate proved to be able to significantly improve marble cohesion and led to lower residual strain after heating–cooling cycles, compared to untreated marble. The DAP-treatment also exhibited a significant ability to slow down further bowing of already bowed slabs and to prevent bowing of initially planar slabs

The marble sculptures of General Bülow and Scharnhorst in Berlin: comparative, non-destructive analysis of the weathering state after 12 years of exposure

After almost 200 years of exposure, the monuments of General Scharnhorst and Bülow have been analysed by means of ultrasound. Both sculptures are made of Carrara marble, both sculptures have been exposed to the same environmental influences and both sculptures are, based on the results of the ultrasonic measurements, in alarming conditions. This statement can be made because of the data of three different measurement investigations within the last 12 years. In this short exposure time, the already low velocities have been reduced by 16.2% and 14.7%. The very low average velocity of 2.8 km/s for the sculpture of General Bülow and a slightly higher average velocity of 3.2 km/s for the Scharnhorst sculpture indicate that both sculptures are in a poor condition, even though a protective winter shelter has been used since 2004. Comparing tomographic velocity measurements performed in 2006 with the measurements made in 2018 was possible and showed that even areas with a thickness up to 90 cm show alarming low ultrasonic velocities down to 2.6 km/s. Even if the circumstances for both sculptures have been the same, they differ in their weathering state. The careful and transparent documentation of all measurements was in this context the most important aspect for the comparative studies. Irregularities in their weathering behaviour of the two statues can be distinguished, allowing an in-depth analysis of the deterioration of the marble.Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/50110000234

The marble sculptures of General Bülow and Scharnhorst in Berlin: comparative, non-destructive analysis of the weathering state after 12 years of exposure

After almost 200 years of exposure, the monuments of General Scharnhorst and Bülow have been analysed by means of ultrasound. Both sculptures are made of Carrara marble, both sculptures have been exposed to the same environmental influences and both sculptures are, based on the results of the ultrasonic measurements, in alarming conditions. This statement can be made because of the data of three different measurement investigations within the last 12 years. In this short exposure time, the already low velocities have been reduced by 16.2% and 14.7%. The very low average velocity of 2.8 km/s for the sculpture of General Bülow and a slightly higher average velocity of 3.2 km/s for the Scharnhorst sculpture indicate that both sculptures are in a poor condition, even though a protective winter shelter has been used since 2004. Comparing tomographic velocity measurements performed in 2006 with the measurements made in 2018 was possible and showed that even areas with a thickness up to 90 cm show alarming low ultrasonic velocities down to 2.6 km/s. Even if the circumstances for both sculptures have been the same, they differ in their weathering state. The careful and transparent documentation of all measurements was in this context the most important aspect for the comparative studies. Irregularities in their weathering behaviour of the two statues can be distinguished, allowing an in-depth analysis of the deterioration of the marble