Mobile Gamma Spectrometry Survey of the Scottish Enterprise Technology Park, East Kilbride, 17th-19th August 2009

<p>Environmental radioactivity arises from natural geological sources, the redistribution of natural activity through industrial processes, the nuclear industry including routine and accidental discharges into the environment, and various medical or industrial uses of radioisotopes. Mobile gamma spectrometry provides a powerful means of measuring the distribution of radioactivity in the environment. Data collected by such methods provide measures of environmental quality, references for public health assurance, means to assess environmental change, and other uses. Airborne Gamma Spectrometry (AGS) has been developed at SUERC for environmental purposes since 1988, and provides a capability for very rapid and cost effective surveys of large areas, and provides for visualisation and classification of enhanced features of radioactivity within the context of natural variations. Ground based approaches, with equipment mounted on vehicles or backpacks, provide more detailed spatial resolution for smaller areas at significantly reduced area coverage rates.</p> <p>A portable gamma spectrometry system has been developed at SUERC, consisting of a 3x3” NaI(Tl) detector with a digital spectrometer and GPS receiver using a netbook computer for data acquisition. This system can be carried as a backpack and used to conduct surveys of environmental radioactivity in urban areas, where people spend their time.</p> <p>Detector backgrounds and stripping matrices have been measured. A survey of approximately 50,000 m2 of the Scottish Enterprise Technology Park (SETP) has been conducted with two detector systems. The SETP is on the site of the National Engineering Laboratory (NEL) established in East Kilbride in 1948, and acquired by Scottish Enterprise in 1994. In recent years there has been an ongoing programme of renovation on the site, including demolition of old buildings and new construction along with landscaping operations.</p> This report presents the results of initial detector characterisation and the survey of part of the SETP site. Detector stripping matrices were determined from measurements made on the 18th August 2009, with background measurements on Loch Lomond collected on the 28th. The site survey was conducted between 17th and 19th August 2009, with over 4600 spectra with 10s integration time collected. Maps of the distribution of 137Cs, 40K, 214Bi, 208Tl and gamma dose rate were produced. The 137Cs activity clearly shows areas undisturbed since 1986, with fallout from the Chernobyl accident still present on the grass. The footprint of the demolished research reactor at SUERC is evident as a negative feature in the 137Cs map. The natural series activities and gamma dose rate show the range of materials used for building and road construction, including one small area of Technologically Enhanced Naturally Occurring Radioactive Material (TENORM), and the local geology and soils. This demonstrates the capability of the SUERC portable gamma spectrometry system to collect high quality data of an area with a complex history, land use and range of buildings. Further application of the technique to other urban areas, and the rest of the SETP site, would allow similar assessments of the radiation environments of a range of different locations

Demonstration of lightweight gamma spectrometry systems in urban environments

Urban areas present highly complex radiation environments; with small scale features resulting from different construction materials, topographic effects and potential anthropogenic inputs from past industrial activity or other sources. Mapping of the radiation fields in urban areas allows a detailed assessment of exposure pathways for the people who live and work there, as well as locating discrete sources of activity that may warrant removal to mitigate dose to the general public. These areas also present access difficulties for radiometric mapping using vehicles or aircraft. A lightweight portable gamma spectrometry system has been used to survey sites in the vicinity of Glasgow to demonstrate the possibilities of radiometric mapping of urban areas, and to investigate the complex radiometric features such areas present. Variations in natural activity due to construction materials have been described, the presence of 137Cs used to identify relatively undisturbed ground, and a previously unknown NORM feature identified. The effect of topographic enclosure on measurements of activity concentration has been quantified. The portable system is compared with the outputs that might be expected from larger vehicular or airborne systems. For large areas airborne surveys are the most cost effective approach, but provide limited spatial resolution, vehicular surveys can provide sparse exploratory data rapidly or detailed mapping of open areas where off-road access is possible. Backpack systems are ideally suited to detailed surveys of small areas, especially where vehicular access is difficult

High Pressure Insulator-Metal Transition in Molecular Fluid Oxygen

We report the first experimental evidence for a metallic phase in fluid molecular oxygen. Our electrical conductivity measurements of fluid oxygen under dynamic quasi-isentropic compression show that a non-metal/metal transition occurs at 3.4 fold compression, 4500 K and 1.2 Mbar. We discuss the main features of the electrical conductivity dependence on density and temperature and give an interpretation of the nature of the electrical transport mechanisms in fluid oxygen at these extreme conditions.Comment: RevTeX, 4 figure

'This is what democracy looks like' : New Labour's blind spot and peripheral vision

New Labour in government since 1997 has been roundly criticized for not possessing a clear, coherent and consistent democratic vision. The absence of such a grand vision has resulted, from this critical perspective, in an absence of 'joined-up' thinking about democracy in an evolving multi-level state. Tensions have been all too apparent between the government's desire to exert central direction - manifested in its most pathological form as 'control freakery' - and its democratising initiatives derived from 'third-way' obsessions with 'decentralising', 'empowering' and 'enabling'. The purpose of this article is to examine why New Labour displayed such apparently impaired democratic vision and why it appeared incapable of conceiving of democratic reform 'in the round'. This article seeks to explain these apparent paradoxes, however, through utilising the notion of 'macular degeneration'. In this analysis, the perceived democratic blind spot of New Labour at Westminster is connected to a democratic peripheral vision, which has envisaged innovative participatory and decentred initiatives in governance beyond Westminster

The scale of population structure in Arabidopsis thaliana

The population structure of an organism reflects its evolutionary history and influences its evolutionary trajectory. It constrains the combination of genetic diversity and reveals patterns of past gene flow. Understanding it is a prerequisite for detecting genomic regions under selection, predicting the effect of population disturbances, or modeling gene flow. This paper examines the detailed global population structure of Arabidopsis thaliana. Using a set of 5,707 plants collected from around the globe and genotyped at 149 SNPs, we show that while A. thaliana as a species self-fertilizes 97% of the time, there is considerable variation among local groups. This level of outcrossing greatly limits observed heterozygosity but is sufficient to generate considerable local haplotypic diversity. We also find that in its native Eurasian range A. thaliana exhibits continuous isolation by distance at every geographic scale without natural breaks corresponding to classical notions of populations. By contrast, in North America, where it exists as an exotic species, A. thaliana exhibits little or no population structure at a continental scale but local isolation by distance that extends hundreds of km. This suggests a pattern for the development of isolation by distance that can establish itself shortly after an organism fills a new habitat range. It also raises questions about the general applicability of many standard population genetics models. Any model based on discrete clusters of interchangeable individuals will be an uneasy fit to organisms like A. thaliana which exhibit continuous isolation by distance on many scales

Acute Physiological Responses to Resistance Exercise With Continuous Versus Intermittent Blood Flow Restriction A Randomized Controlled Trial

The primary goal of this investigation was to examine the physiological responses of blood flow restriction (BFR) resistance exercise (RE) performed with continuous or intermittent BFR and to compare these results to those from conventional high- and low-load RE without BFR. Fourteen men randomly completed the following experimental trials: (1) low-load RE with continuous BFR (cBFR), (2) low-load RE with intermittent BFR (iBFR), (3) low-load RE without BFR (LI), and (4) conventional high-load RE without BFR (HI). For the cBFR, iBFR, and LI exercise trials, participants performed four sets of 30–15–15–15 repetitions of the bilateral leg press (LP) and knee extension (KE) exercises, at an intensity of 20% of their one-repetition maximum (1-RM), at a 1.5-s contraction speed, and with a 1-min rest period between sets. The only difference between the cBFR and iBFR protocols was that the pressure of the cuffs was released during the rest intervals between sets for the iBFR trial. For the HI trial, participants completed four sets of 10 repetitions of the same exercises, at 70% of 1-RM, with a 1-min rest period between sets, and at the same contraction speed. Muscle activity was assessed during each set using superficial electromyography, as well as changes in blood lactate concentration [La–] from baseline at 5 min post exercise and in muscle swelling and plasma volume (%ΔPV) at 5 and 15 min post exercise. There were no significant differences in muscle activity (p < 0.05) across the cBFR, iBFR, and LI protocols at any time point, whereas they were all significantly lower than HI. There were also no significant (p < 0.05) differences across the three low-load RE conditions for [La–],%ΔPV, or muscle swelling. HI elicited significantly (p < 0.05) greater responses than cBFR, iBFR, and LI for all the physiological markers measured. In conclusion, RE combined with cBFR or iBFR induce the same acute physiological responses. However, the largest physiological responses are observed with HI, probably because of the significantly greater exercise volumes. Therefore, releasing the pressure of the restrictive cuffs during the rest periods between sets will not hinder the acute physiological responses from BFR RE.Financial support was provided from the Office of the Vice President for Research and Partnerships and the Office of the Provost, University of Oklahoma. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

Genome-wide Identity-by-Descent Sharing among CEPH Siblings

The concept of genetic identity–by–descent (IBD) has markedly advanced our understanding of the genetic similarity among relatives and triggered a number of developments in epidemiological genetics. However, no empirical measure of this relatedness throughout the whole human genome has yet been published. Analyzing highly polymorphic genetic variations from the Centre d’études du polymorphisme humain (CEPH) database, we report the first genome–wide estimation of the mean and variation in IBD sharing among siblings. From 1,522 microsatellite markers spaced at an average of 2.3 cM on 498 sibling pairs, we estimated a mean of 0.4994 and a standard deviation of 0.0395. In order to account for the impact of varying chromosomal lengths and recombination rates, the analysis was also performed at the chromosomal and marker levels and for paternal and maternal DNA separately. Based on the variation, we estimate an “effective number of segregating loci” of around 80 for sibling pairs over the whole genome (i.e., the number of loci that would yield the same standard deviation in IBD sharing if all loci were segregating independently). Finally, we briefly assess the impact of genotyping errors on IBD estimations, compare our results to published theoretical and simulated expectations, and discuss some implications of our findings