PCBs and OCPs in male harbour,grey, harp and hooded seals from the Estuary and Gulf of St Lawrence,Canada

Blubber samples from adult male harbour seals (Phoca vitulina) from the St Lawrence Estuary, and from grey (Halichoerus grypus), harp (Phoca groenlandica) and hooded (Cystophora cristata) seals from the Gulf of St Lawrence, were analysed for polychlorinated biphenyls (PCB) and organochlorinated pesticides (OCP). All seals were between 5 and 19 years of age, and mean ages were not statistically different among the seal species. Mean concentrations of sigmaPCB and mirex were significantly higher in harbour seals, while sigmaDDT concentrations were significantly higher in hooded seals than in the other species examined. Harbour and hooded seals had similar concentrations of sigmaCHLOR, which were higher than in grey and harp seals. SigmaHCH concentrations were significantly higher in harp seals than in harbour and hooded seals and they were significantly higher in harbour and grey seals than in hooded seals. Harp and grey seals had similar levels of HCB, which were significantly higher than in either hooded or harbour seals. Patterns of PCB congeners and individual OCPs varied considerably between the four species. In PCA plots harbour, harp and hooded seals were well separated from each other, while grey seals were separated from the other species by a smaller degree. Between species variations may be explained by their dissimilar migratory patterns, habitat use and proximity to sources of industrial and agricultural pollution, their dietary regime (trophic level and individual prey items) as well as possible variations in the seals' abilities to eliminate these compounds.     

Direct quantification of inorganic polyphosphate in microbial cells using 4'-6-diamidino-2-phenylindole (DAPI)

Inorganic polyphosphate (polyP) is increasingly being recognized as an important phosphorus sink within the environment, playing a central role in phosphorus exchange and phosphogenesis. Yet despite the significant advances made in polyP research there is a lack of rapid and efficient analytical approaches for the quantification of polyP accumulation in microbial cultures and environmental samples. A major drawback is the need to extract polyP from cells prior to analysis. Due to extraction inefficiencies this can lead to an underestimation of both intracellular polyP levels and its environmental pool size: we observed 23-58% loss of polyP using standard solutions and current protocols. Here we report a direct fluorescence based DAPI assay system which removes the requirement for prior polyP extraction before quantification. This increased the efficiency of polyP detection by 28-55% in microbial cultures suggesting quantitative measurement of the intracellular polyP pool. It provides a direct polyP assay which combines quantification capability with technical simplicity. This is an important step forward in our ability to explore the role of polyP in cellular biology and biogeochemical nutrient cycling.     

Emissions of volatile organic compounds originating from UK livestock agriculture

In this paper we estimate the quantity of non‐methane volatile organic compounds (NMVOCs) emitted from UK livestock. The final estimate is derived from published values and from direct measurements of NMVOC emissions from dairy cattle slurry and laying hen manure. Emission rates of NMVOCs were determined for fresh dairy cattle slurry and laying hen manure using a 40 m³ emissions chamber. Dimethyl sulphides dominated emissions from laying hen manure at 753 ± 263 g m^?3 day^?1. Emissions from dairy cattle slurry were dominated by volatile fatty acids (C₂? C₅, 6.3 ± 3.1 g m^?3 day^?1) and phenols (2.4 ± 1.2 g m^?3 day^?1). Many of these NMVOCs are decomposition products from protein sources from which ammonia is also a by‐product. There is a close association between ammonia and NMVOC production from manure, and on this basis we estimated the annual NMVOC emissions from UK livestock as 165 ± 56 kt for 2002. These emissions compare to those from the larger industrial and transport sectors and exceed the 50–100 kt C year^?1 currently determined as originating from biogenic sources including agriculture. These findings have implications for air quality, and these NMVOCs may affect the cleansing capacity of the troposphere. Copyright © 2004 Society of Chemical Industry     

DEVELOPMENT OF FT-IR ATTENUATED TOTAL INTERNAL REFLECTION DICHROISM TECHNIQUES FOR STRUCTURAL CHARACTERIZATION OF POLYMER SURFACES

We describe our continuing effort to develop FT-IR attenuated total reflection (ATR) dichroism techniques for the characterization of polymer surface structure and molecular orientation. Following theoretical background, we review the two-dimensional and three-dimensional analyses work based on a specially designed internal reflection crystal and a specially built ATR-sample attachment. In the current development section, we describe briefly the intensity correction procedures used in variable angle studies and an attempt to design a hemispheric crystal attachment to eliminate problems encountered with face-cut reflection crystals.     

Recent studies of uranium and plutonium chemistry in alkaline radioactive waste solutions

Solubility studies of uranium and plutonium in a caustic, radioactive Savannah River Site tank waste solution revealed the existence of uranium supersaturation in the as-received sample. Comparison of the results to predictions generated from previously published models for solubility in these waste types revealed that the U model poorly predicts solubility while Pu model predictions are quite consistent with experimental observations. Separate studies using simulated Savannah River Site evaporator feed solution revealed that the known formation of sodium aluminosilicate solids in waste evaporators can promote rapid precipitation of uranium from supersaturated solutions.     

DRIVERS OF RIPARIAN TREE INVASION ON A DESERT STREAM

Understanding mechanisms of exotic species' invasions is essential to managing riparian landscapes throughout the world. In the southwestern USA, the two most dominant invaders of riparian habitats are the exotic tree species tamarisk (Tamarix ramosissima, Tamarix chinensis, and their hybrids) and Russian olive (Elaeagnus angustifolia). These plants were introduced around 1900, and their success may be facilitated by river regulation, river channel changes, and precipitation patterns. We hypothesized that riparian invasion in Canyon de Chelly, Arizona, was initiated by a change point event such as plantings, dam construction, or channel incision and that establishment near a change point was tied to flood events. We aged tamarisk, Russian olive, and native cottonwood trees from study sites in Canyon de Chelly and used tree ring analysis to determine the year of establishment and the elevation of the germination point relative to the channel. We used Bayesian Poisson regression and information theoretics to identify change points and precipitation variables driving annual tree establishment. We found that most tamarisk and Russian olive trees established in the late 1980s, and most cottonwoods established in 1930‐1950 and 1980‐2000. Regression models indicated that change points occurred in 1983 for Russian olive and 1988 for tamarisk, and precipitation was important for establishment. Although plantings and river regulation probably played a role in tree invasion, our results suggest that these species required precipitation and stream channel change for widespread establishment in Canyon de Chelly. The factors driving riparian invasions may not be those often associated with degraded rivers, such as altered hydrographs and land management changes, thus requiring analyses of the full range of ecological and physical processes. Copyright © 2012 John Wiley & Sons, Ltd.     

A concurrent process creation service to support SPMD based parallel processing on COWs

Current software environments used to support parallel processing on a cluster of workstations (COW) are not satisfactory, do not provide complete transparency and are not specifically designed for parallel processing. In particular, the establishment of a parallel processing environment and the initialisation of parallel processes suffer from poor performance. Each parallel process of an application is created sequentially and in many cases the logon operation must be completed before remote resources could be acquired. These operations are also performed manually. We present in this paper an original approach that addresses the problem of parallel process creation. The remote workstations are acquired completely transparently and dynamically, and parallel processes are created concurrently. To demonstrate the feasibility of this approach we show a system based on RHODOS (a client/server and microkernel based distributed operating system), specifically designed to improve the performance of process instantiation and therefore able to improve the overall execution performance of parallel programs, in particular parallel process creation. Copyright © 1999 John Wiley & Sons, Ltd.