991 research outputs found

    Radiometric Flight Trials in the Forth Estuary on 7/8/91

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    A brief radiometric flight trial was undertaken on 7th August 1991, essentially to prove a new gamma spectrometry installation. A twin engined helicopter operated by Dollar helicopters out of Cumbernauld Airport was used for the exercise. The new equipment under test comprised (i) a spectrometer mounting plate manufactured by Dollar to take SURRC equipment for rapid deployment, (ii) a 19" rack mounted spectrometer incorporating proven SURRC components, but with additional duplex inverter based UPS, and (iii) a Navstar XR4 GPS system with aircraft patch type aerial. The flight trial was conducted in the Forth Estuary area focussing on three small sites of incidental interest

    A Brief Aerial Survey in the Vicinity of Sellafield in September 1990

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    A two day survey exercise was conducted by SURRC from 25th-26th September 1990 with the joint aims of demonstrating the potential of helicopters for emergency response and beginning the definition of baseline levels in the immediate vicinity of Sellafield. The aircraft used for this work was a twin engined AS 355 "Squirrel" helicopter chartered from Dollar Helicopters. It was loaded with an 8 litre NaI gamma spectrometry system at SURRC in East Kilbride on the afternoon of 24th September and flown down to Sellafield the same day. Over the following two days roughly 1300 gamma ray spectra were recorded from an area ranging south from an EW line linking Ennerdale Fell and St. Bees Head to beyond Ravenglass. Operations were conducted from the Sellafield helipad, the aircraft being refuelled at Barrow in Furness. The flights were arranged to provide nominally 1km spaced parallel NS flight lines throughout the survey area, for the purpose of baseline mapping. Supplementary flights to improve spatial resolution are possible at a later stage. In addition a rapid response flight route was rehearsed involving definition of landward arcs at 10km, 5km and 2km radii from Sellafield plus the beachline from St. Bees Head to Ravenglass. The precise path was chosen to be navigable under most weather conditions and took roughly 40 minutes to fly. A survey aircraft arriving from East Kilbride could perform such a survey without pausing to refuel. The results have been stored archivally and used to map the naturally occurring nuclides 40K, 214Bi, 208Tl together with 137 Cs and total gamma ray flux. The maps presented are spatially smoothed, both by the inherent character of the aerial survey technique and by the colour contouring processes. This leads to a tendency to broaden spatial features, while slightly reducing maximum values, and should be taken into account when interpreting the maps. Greater spatial detail could be achieved with closer flight line spacing. Activity due to Sellafield was readily detected in the area and can be seen clearly in the maps. It is noted that the levels observed are generally comparable with those in BNFL annual reports and other research publications. Furthermore, with a few exceptions, naturally occurring radionuclides are the dominant radiation source in much of the survey area, and show considerable variations from place to place. 137Cs due to marine discharges was most pronounced in the Irt, Mite and Esk estuaries and on the beachline close to the plant. The same nuclide was detected at lower levels in terrestrial areas due to a combination of global fallout, aerial discharges from the plant and the Chernobyl accident. 41Ar and 16N activities were detected in the immediate vicinity of Calder Hall. A small feature was detected at Drigg, probably associated with current operations on the site, and equivalent to an enhancement of less than twice the local natural background. Radiation levels due to current activities on the Sellafield site fall off rapidly with distance from the perimeter, approaching natural levels within 0.5-1km at the time of the survey. Those from the marine, estuarine and tide washed environments are mostly attributed to past marine discharges, and can be expected to continue to receive attention in the future

    Assessment of Chemical Compounds for in vitro and in vivo Activity against Bacterial Black Spot of Mango

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    Bacterial black spot of mango caused by Xanthomonas campestris pv. mangiferaeindicae (Xcm) produces considerable economic losses in many parts in india. The extent to which bactericides control this disease effectively is low. In this study the bactericidal effect of different products was assessed in vitro and in vivo in mango plants under greenhouse conditions. Thirteen antibacterial substances, one commercial formulate and also combinations were tested. In vitro analysis showed that minimal inhibitory concentration (MIC) of antibacterial substances was between 2–8 µgml-1, except for copper sulphate with a MIC value of 100 µgml-1and Vancomycin, Amoxycillin which was not active at 1000 µgml-1. MIC values of commercial formulate bactrinashak  ranged between 5 and 30 µgml-1, and combinations of ciprofloxacin + copper sulphate; ciprofloxacin + bactrinashak; ciprofloxacin + copper oxychloride, ciprofloxacin + tetracycline and tetracycline + bactrinashak, showed a great effect at sub-inhibitory concentrations. Treatments including copper sulphate and copper oxychloride significantly reduced disease symptoms on plants, whereas bacitracin was less effective, where as fluconozole and penicillin does not show any inhibition. In two different field trials, the percentage of leaves symptoms was lower, after treatment with copper sulphate combinations than in inoculated controls. These combinations of different antibacterial substances results were better than copper sulphate alone. We conclude that the combination of copper sulphate with ciproflaxacin may be useful in controlling symptoms of this disease in greenhouses

    An Institutional Theory perspective on sustainable practices across the dairy supply chain

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    AbstractThe need for sustainable practices in the food supply chain, particularly in the area of energy reduction, is becoming acute. The food industry currently has to contend with multiple competing pressures alongside the new challenges of sustainable production. We applied Institutional Theory to explore the role of supermarkets in the development of legitimate sustainable practices across the dairy supply chains. The paper focuses on dairy supply chain organizations and their consumption of energy. We conducted 70 semi-structured telephone interviews with various stakeholders across the supply chain. Findings revealed that the majority of actors in the supply chain identified supermarkets as the dominant player, and that the supermarkets exert pressure on other smaller organizations across the supply chain. Although some organizations wished to pursue a sustainable agenda through integrating new rules and legitimate practices within their own organization, the dominant logic appeared to be one of cost reduction and profit maximization. There was also evidence that supermarkets and other large organizations attempt to replicate publicly available information on green successes for image purposes. We conclude that the dominant logic of cost reduction is so well established that challenging the dominant logic may prove difficult. The challenge is therefore to complement the dominant logic with sustainable practices across the whole supply chain, a role Government needs to play. This will require a broader more systemic approach to encouraging sustainable practices including investment and financing practices, so that all members of the dairy supply chain can co-operate and contribute to energy reduction

    Limiting fragmentation in hadron-hadron collisions at high energies

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    Limiting fragmentation in proton-proton, deuteron-nucleus and nucleus-nucleus collisions is analyzed in the framework of the Balitsky-Kovchegov equation in high energy QCD. Good agreement with experimental data is obtained for a wide range of energies. Further detailed tests of limiting fragmentation at RHIC and the LHC will provide insight into the evolution equations for high energy QCD.Comment: 28 pages, 10 figures (2 new figures, text slightly expanded, and some additional references

    From Data to Causes II: Comparing Approaches to Panel Data Analysis

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    This article compares a general cross-lagged model (GCLM) to other panel data methods based on their coherence with a causal logic and pragmatic concerns regarding modeled dynamics and hypothesis testing. We examine three “static” models that do not incorporate temporal dynamics: random- and fixed-effects models that estimate contemporaneous relationships; and latent curve models. We then describe “dynamic” models that incorporate temporal dynamics in the form of lagged effects: cross-lagged models estimated in a structural equation model (SEM) or multilevel model (MLM) framework; Arellano-Bond dynamic panel data methods; and autoregressive latent trajectory models. We describe the implications of overlooking temporal dynamics in static models and show how even popular cross-lagged models fail to control for stable factors over time. We also show that Arellano-Bond and autoregressive latent trajectory models have various shortcomings. By contrasting these approaches, we clarify the benefits and drawbacks of common methods for modeling panel data, including the GCLM approach we propose. We conclude with a discussion of issues regarding causal inference, including difficulties in separating different types of time-invariant and time-varying effects over time
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