5,648 research outputs found

    Towards a shared method to classify contaminated territories in the case of an accidental nuclear event: the PRIME project

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    The analysis of the management of the accidentally radioactive contaminated areas such as those around Chernobyl nuclear power plant highlights the fact that the current spatial classification methods hardly help in recovering proper use of the contaminated territory. The cause is mainly to be searched for in the traditional construction of risks assessment methods; these methods rest on criteria defined by institutional experts, which are not applicable in practise because they are not shared by all the stakeholders involved in the management of the contaminated territories. Opposite such top-down tentative management, local efforts supported by Non-Governmental Organizations to restore life in the contaminated area seem to be more fruitful but very time and resources consuming and limited to the specific areas where they are experimented. The aim of the PRIME project, in progress at the French Institute for Radioprotection and Nuclear Safety, is to mix the advantages of both approaches in building a multicriteria decision tool based on the territorial specificities. The criteria of the method are chosen and weighted with representatives of the territory’s stakeholders (decision makers, local actors and experts) to warrant that all the points of view are taken into account and to enable the risk managers to choose the appropriate strategy in case of an accident involving radioactive substances. The area chosen for the pilot study is a 50 km radius territory around the nuclear sites of Tricastin-Pierrelatte in the lower valley of Rhône (France). One of the exploration questions of the PRIME project is whether a multicriteria method may be an appropriate tool to treat the data and make them visible and accessible for all the stakeholders

    Quantitative detection of atropine-delayed gastric emptying in the horse by the <sup>13</sup>C-octanoic acid breath test

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    The &lt;sup&gt;13&lt;/sup&gt;C-octanoic acid breath test has been correlated significantly to radioscintigraphy for measurement of gastric emptying indices in healthy horses. The objective of this study was to investigate the validity of the test for measurement of equine delayed gastric emptying, prior to its potential clinical application for this purpose. A model of atropine- induced gastroparesis was used. Gastric emptying rate was measured twice in 8 horses using concurrent radioscintigraphy and/or breath test after treatment i.v. with either atropine (0.035 mg/kg bwt) or saline in randomised order. Analysis of both data sets demonstrated that the atropine treatment had caused a significant delay in gastric emptying rate. Paired breath test data showed an atropine-induced delay in gastric half-emptying time t(1/2)), with no overlap in the 99% Cl range (P&#60;0.001). Significant correlations were found between scintigraphy and &lt;sup&gt;13&lt;/sup&gt;C-octanoic acid breath test for calculation of both t(1/2) (P&#60;0.01) and lag phase duration (P&#60;0.05) in the atropine-delayed emptying results. The mean (s.d.) bias in breath test t(1/2) when compared with scintigraphy was 1.78 (0.58) h. The results demonstrated that the &lt;sup&gt;13&lt;/sup&gt;C-octanoic acid breath test was an effective diagnostic modality for the measurement of equine delayed gastric emptying. The technique offers advantages to existing methods for clinical investigation, as it is noninvasive, not radioactive, quantitative and requires minimal equipment or training to perform

    Unemployment Duration, Schooling and Property Crime

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    It is well known that there is no consensus with respect to the relationship between unemployment and crime. As well, there is very little research on the linkages between crime and the educational experiences of young people. In this paper we show a very strong positive relationship between criminal activity and the extent of youth male long-term unemployment. We also show that criminal activity is negatively associated high school completions, and positively associated with high school non-completion rates. The analysis suggests that labour market and education policies have the potential to significantly reduce property crime. However, increased high school participation of the targeted group only decreases crime if it results in graduation. This suggests that the effectiveness of education policy is a critical influence on crime activity, a unique finding for the literature

    Thulium and ytterbium-doped titanium oxide thin films deposited by ultrasonic spray pyrolysis

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    Thin films of thulium and ytterbium-doped titanium oxide were grown by metal-organic spray pyrolysis deposition from titanium(IV)oxide bis(acetylacetonate), thulium(III) tris(2,2,6,6-tetramethyl-3,5-heptanedionate) and ytterbium(III) tris(acetylacetonate). Deposition temperatures have been investigated from 300{\deg}C to 600{\deg}C. Films have been studied regarding their crystallity and doping quality. Structural and composition characterisations of TiO2:Tm,Yb were performed by electron microprobe, X-ray diffraction and Fourier transform infrared spectroscopy. The deposition rate can reach 0.8 \mum/h. The anatase phase of TiO2 was obtained after synthesis at 400{\deg}C or higher. Organic contamination at low deposition temperature is eliminated by annealing treatments.Comment: 6 pages, 6 figure

    Fresh concrete pumping arrest investigation for thixotropy by a CFD modelling apporach

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    Concrete pumping operations determine construction speed, finishing quality, durability and even structural integrity. When pumping operations cannot be continued, most problems occur due to complex time-dependent transformations. This causes significant industrial costs (e.g. material and delay). Since time-dependent aspects are currently not fully understood and cannot be predicted, a way to quantify time-dependent aspects is needed. Therefore, we make an attempt by numerical simulation by comparing thixotropic cases with different pumping arresting times. After an introduction to fresh concrete rheology and numerical modelling, ten representative thixotropy cases are analysed. Despite some unresolved numerical instabilities, the numerical framework allows to estimate pumping pressure peaks after resting time. The results evaluate a thixotropy model, which is generally applicable for less thixotropic SCC’s. It is clear that flow re-initiation after rest in concrete pumping is poorly understood. Numerical simulation could be one approach for further analysis and is potentially important for practice. Future work such as simulation of concrete mixers, pressure increase after pumping arrest, formwork pressure decay and leakage are therefore recommended

    Acid/base-triggered switching of circularly polarized luminescence and electronic circular dichroism in organic and organometallic helicenes.

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    Electronic circular dichroism and circularly polarized luminescence acid/base switching activity has been demonstrated in helicene-bipyridine proligand 1 a and in its “rollover” cycloplatinated derivative 2 a. Whereas proligand 1 a displays a strong bathochromic shift (>160 nm) of the nonpolarized and circularly polarized luminescence upon protonation, complex 2 a displays slightly stronger emission. This strikingly different behavior between singlet emission in the organic helicene and triplet emission in the organometallic derivative has been rationalized by using quantum-chemical calculations. The very large bathochromic shift of the emission observed upon protonation of azahelicene-bipyridine 1 a has been attributed to the decrease in aromaticity (promoting a charge-transfer-type transition rather than a π–π* transition) as well as an increase in the HOMO–LUMO character of the transition and stabilization of the LUMO level upon protonation

    Mid-J CO Emission From NGC 891: Microturbulent Molecular Shocks in Normal Star Forming Galaxies

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    We have detected the CO(6-5), CO(7-6), and [CI] 370 micron lines from the nuclear region of NGC 891 with our submillimeter grating spectrometer ZEUS on the CSO. These lines provide constraints on photodissociation region (PDR) and shock models that have been invoked to explain the H_2 S(0), S(1), and S(2) lines observed with Spitzer. We analyze our data together with the H_2 lines, CO(3-2), and IR continuum from the literature using a combined PDR/shock model. We find that the mid-J CO originates almost entirely from shock-excited warm molecular gas; contributions from PDRs are negligible. Also, almost all the H_2 S(2) and half of the S(1) line is predicted to emerge from shocks. Shocks with a pre-shock density of 2x10^4 cm^-3 and velocities of 10 km/s and 20 km/s for C-shocks and J-shocks, respectively, provide the best fit. In contrast, the [CI] line emission arises exclusively from the PDR component, which is best parameterized by a density of 3.2x10^3 cm^-3 and a FUV field of G_o = 100 for both PDR/shock-type combinations. Our mid-J CO observations show that turbulence is a very important heating source in molecular clouds, even in normal quiescent galaxies. The most likely energy sources for the shocks are supernovae or outflows from YSOs. The energetics of these shock sources favor C-shock excitation of the lines.Comment: 18 pages, 2 figures, 6 tables, accepted by Ap
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