Revising the Emergency Management Requirements for new generation reactors

The paper presents the application of a new risk-informed methodology for the identification of the Emergency Management Requirements (EMR) to a Generation II, Large size Reactor and a Generation III+ Small Modular Reactor. The results obtained in this test case demonstrate that the actual EMR is conservative, as expected, for the GenII reactor, while the new methodology could be applied for the definition of EMRs for the new generation Nuclear Power Plants, with a possible reduction of the emergency area without loss of safety level. By adopting both probabilistic and deterministic approaches, the study addresses possible accidents and corresponding release scenarios for the two types of reactor, calculates the areas where the accidents have an impact on the population and defines the new EMR considering the health effects on the population

Methanotrophy potential versus methane supply by pore water diffusion in peatlands

International audienceLow affinity methanotrophic bacteria consume a significant quantity of methane in wetland soils in the vicinity of plant roots and at the oxic-anoxic interface. Estimates of the efficiency of methanotrophy in peat soils vary widely in part because of differences in approaches employed to quantify methane cycling. High resolution profiles of dissolved methane abundance measured during the summer of 2003 were used to quantify rates of upward methane flux in four peatlands situated in Wales, UK. Aerobic incubations of peat from a minerotrophic and an ombrogenous mire were used to determine depth distributions of kinetic parameters associated with methane oxidation. The capacity for methanotrophy in a 3 cm thick zone immediately beneath the depth of nil methane abundance in pore water was significantly greater than the rate of upward diffusion of methane in all four peatlands. Rates of methane diffusion in pore water at the minerotrophic peatlands were small (?mol l?1 methane, indicating that precipitation events can impact methane distributions in pore water. Further work is needed to characterise the kinetics of methane oxidation spatially and temporally in different wetland types in order to determine generalized relationships for methanotrophy in peatlands that can be incorporated into process-based models of methane cycling in peat soils

On the Effective Description of Large Volume Compactifications

We study the reliability of the Two-Step moduli stabilization in the type-IIB Large Volume Scenarios with matter and gauge interactions. The general analysis is based on a family of N=1 Supergravity models with a factorizable Kaehler invariant function, where the decoupling between two sets of fields without a mass hierarchy is easily understood. For the Large Volume Scenario particular analyses are performed for explicit models, one of such developed for the first time here, finding that the simplified version, where the Dilaton and Complex structure moduli are regarded as frozen by a previous stabilization, is a reliable supersymmetric description whenever the neglected fields stand at their leading F-flatness conditions and be neutral. The terms missed by the simplified approach are either suppressed by powers of the Calabi-Yau volume, or are higher order operators in the matter fields, and then irrelevant for the moduli stabilization rocedure. Although the power of the volume suppressing such corrections depends on the particular model, up to the mass level it is independent of the modular weight for the matter fields. This at least for the models studied here but we give arguments to expect the same in general. These claims are checked through numerical examples. We discuss how the factorizable models present a context where despite the lack of a hierarchy with the supersymmetry breaking scale, the effective theory still has a supersymmetric description. This can be understood from the fact that it is possible to find vanishing solution for the auxiliary components of the fields being integrated out, independently of the remaining dynamics. Our results settle down the question on the reliability of the way the Dilaton and Complex structure are treated in type-IIB compactifications with large compact manifold volumina.Comment: 23 pages + 2 appendices (38 pages total). v2: minor improvements, typos fixed. Version published in JHE

Reatores Aeróbicos para o Biotratamento de Águas Poluídas e Efluentes Sintéticos Contendo Ácido 3-Clorobenzóico

The degradation of 3-chlorobenzoic acid in polluted waters and synthetic effluents by a previously isolated indigenous strain of Pseudomonas putida was studied. Batch biodegradation assays were performed using a 2 L microfermentor at 28 °C with agitation. To simulate polluted water, 100 mg.L–1 of 3-chlorobenzoic acid were added to surface river water. Continuous‑flow assays were performed in an aerobic up-flow fixed-bed reactor constructed from PVC employing hollow PVC cylinders as support material. Synthetic wastewater was prepared by dissolving 3-chlorobenzoic acid in non-sterile groundwater. Biodegradation was evaluated by spectrophotometry, chloride release, gas chromatography and microbial growth. In batch experiments the indigenous strain of Pseudomonas putida degrades 100 mg.L–1 of 3-chlorobenzoic acid in 28 hours with a removal efficiency of 92.2 and 87.2%, expressed as compound and chemical oxygen demand removal, respectively. In the continuous-flow reactor the removal of an average influent concentration of 98.6 mg.L–1 reached 91.7% of compound and 88.9% of COD removal. The process efficiency remained approximately constant despite changes in the influent flow, compound concentration and temperature. The absence of metabolites was determined by gas chromatography performed at the end of the batch process and at the effluent of the continuous reactor. The ability of the isolated indigenous strain to degrade 3-chlorobenzoic acid in both batch and continuous reactors represents a promising feature to improve the treatment of effluents.Foi estudada a degradação do ácido 3-clorobenzóico em águas poluídas e efluentes sintéticos por uma cepa nativa previamente isolada de Pseudomonas putida. Ensaios de biodegradação de lotes foram realizados usando um microfermentador de 2 L a 28 °C sob agitação. Para simular água poluída, 100 mg.L–1 de ácido 3-clorobenzóico foram adicionados a água superficial de rio. Foram realizados ensaios de fluxo contínuo num reator aeróbico de fluxo ascendente de leito fixo construído em PVC, utilizando cilindros de PVC como material de suporte. Água sintética residuária foi preparada dissolvendo ácido 3-clorobenzóico em água subterrânea não estéril. A biodegradação foi avaliada por espectrofotometria, liberação de cloreto, cromatografia gasosa e crescimento microbiano. Nos experimentos em lote, a cepa nativa de Pseudomonas putida degrada 100 mg.L–1 de ácido 3-clorobenzóico em 28 horas com uma eficiência de remoção de 92,2 e 87,2%, expressada como remoção de composto e demanda de oxigênio químico, respectivamente. No reator de fluxo contínuo, a remoção de uma concentração média de afluente de 98,6 mg.L–1 atingiu 91,7% do composto e 88,9% da remoção de COD. A eficiência do processo permaneceu aproximadamente constante apesar das mudanças de fluxo, concentração do composto e temperatura. A ausência de metabólitos foi determinada por cromatografia gasosa realizada no final do processo em lote e no efluente do reator continuo. A capacidade da cepa nativa para degradar o ácido 3-clorobenzóico em ambos os lotes e reatores contínuos representa uma função promissora para melhorar o tratamento de efluentes.Fil: Gallego, A.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Sanidad Nutrición Bromatología y Toxicología; ArgentinaFil: Rossen, Ariana Altair. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Sanidad Nutrición Bromatología y Toxicología; ArgentinaFil: Gemini, V.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Sanidad Nutrición Bromatología y Toxicología; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Fortunato, M. S.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Sanidad Nutrición Bromatología y Toxicología; ArgentinaFil: Rossi, S.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Sanidad Nutrición Bromatología y Toxicología; ArgentinaFil: Planes, E.. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Korol, S.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Sanidad Nutrición Bromatología y Toxicología; Argentin

An Effective Description of the Landscape - II

We continue our analysis of establishing the reliability of "simple" effective theories where massive fields are "frozen" rather than integrated out, in a wide class of four dimensional theories with global or local N=1 supersymmetry. We extend our previous work by adding gauge fields and O(1) Yukawa-like terms for the charged fields in the superpotential. For generic Kaehler potentials, a meaningful freezing is allowed for chiral multiplets only, whereas in general heavy vector fields have to properly be integrated out. Heavy chiral fields can be frozen if they approximately sit to supersymmetric solutions along their directions and, in supergravity, if the superpotential at the minimum is small, so that a mass hierarchy between heavy and light fields is ensured. When the above conditions are met, we show that the simple effective theory is generally a reliable truncation of the full one.Comment: 20 page

Selective oxidation of alkyl and aryl glyceryl monoethers catalysed by an engineered and immobilised glycerol dehydrogenase

Enzymes acting over glyceryl ethers are scarce in living cells, and consequently biocatalytic transformations of these molecules are rare despite their interest for industrial chemistry. In this work, we have engineered and immobilised a glycerol dehydrogenase from Bacillus stearothermophilus (BsGlyDH) to accept a battery of alkyl/aryl glyceryl monoethers and catalyse their enantioselective oxidation to yield the corresponding 3-alkoxy/aryloxy-1-hydroxyacetones. QM/MM computational studies decipher the key role of D123 in the oxidation catalytic mechanism, and reveal that this enzyme is highly enantioselective towards S-isomers (ee > 99%). Through structure-guided site-selective mutagenesis, we find that the mutation L252A sculpts the active site to accommodate a productive configuration of 3-monoalkyl glycerols. This mutation enhances the kcat 163-fold towards 3-ethoxypropan-1, 2-diol, resulting in a specific activity similar to the one found for the wild-type towards glycerol. Furthermore, we immobilised the L252A variant to intensify the process, demonstrating the reusability and increasing the operational stability of the resulting heterogeneous biocatalyst. Finally, we manage to integrate this immobilised enzyme into a one-pot chemoenzymatic process to convert glycidol and ethanol into 3-ethoxy-1-hydroxyacetone and (R)-3-ethoxypropan-1, 2-diol, without affecting the oxidation activity. These results thus expand the uses of engineered glycerol dehydrogenases in applied biocatalysis for the kinetic resolution of glycerol ethers and the manufacturing of substituted hydroxyacetones. This journal i

Survey for Emission-Line Galaxies: Universidad Complutense de Madrid List 3

A new low-dispersion objective-prism search for low-redshift (z<0.045) emission-line galaxies (ELG) has been carried out by the Universidad Complutense de Madrid with the Schmidt Telescope at the Calar-Alto Observatory. This is a continuation of the UCM Survey, which was performed by visual selection of candidates in photographic plates via the presence of the Halpha+[NII]6584 blend in emission. In this new list we have applied an automatic procedure, fully developed by us, for selecting and analyzing the ELG candidates on the digitized images obtained with the MAMA machine. The analyzed region of the sky covers 189 square degrees in nine fields near R.A.=14h & 17h, Dec=25 deg. The final sample contains 113 candidates. Special effort has been made to obtain a large amount of information directly from our uncalibrated plates by using several external calibrations. The parameters obtained for the ELG candidates allow for the study of the statistical properties for the sample.Comment: 13 pages, 18 PostScript figures, 6 JPEG figures, Table 2 corrected. Accepted for publication in Astrophysical Journal Supplements, also available at http://www.ucm.es/info/Astrof/opera/LIST3_ApJS99

Effect of intensive LDL cholesterol lowering with PCSK9 monoclonal antibodies on tendon xanthoma regression in familial hypercholesterolemia

Background and aims: The effect of LDLc lowering with PCSK9 antibodies on tendon xanthomas (TX) is unknown. Methods: TX was measured in 24 heterozygous familial hypercholesterolemia (HeFH) cases and in 24 HeFH controls with or without PCSK9 inhibitors for at least one year. Results: Exposure to PCSK9 inhibitors in cases was 2.96 ± 1.33 years. LDLc decreased 80.8 ± 7.66% in cases and 56.9 ± 11.1% in controls. There was a decrease in maximum (-5.03%) and mean (-5.32%) TX in cases but not in controls (+3.97%, +3.16, respectively, p = 0.01). PCSK9 inhibitor treatment was independently associated with TX reduction. Conclusion: Addition of a PCSK9 inhibitor to statin and ezetimibe resulted in a greater decrease in LDLc and TX after 3 years of treatment