151 research outputs found

    Insights into the composition of recalcitrant organic matter from estuarine sediments using NMR spectroscopy

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    peer-reviewedThe full text of this article will not be available on ULIR until the embargo expires on the 24/05/2018Sediment cores (ca. 6 m) from an estuarine environment gave insights into the composition and preservation of recalcitrant organic carbon (OC) in the environment. The coring locations provided organic matter (OM) of terrestrial origin and of marine origin. Our study specifically focused on the humin (HU), the OM fraction that is most difficult to isolate and to characterize. HU fractions were compared with the total OM recovered after removal of the associated mineral colloids. Solid state and multiphase (nuclear magnetic resonance) NMR experiments were carried out on dried and swollen samples to obtain comparative information about the whole samples and the fractionated samples. The total OM associated with the clay-size fraction provided a standard that allowed differences between the fractions to be observed. The NMR data provided new insights into the molecular structures that become part of the long term C sink in sediments. The recalcitrant OC in the sediments is composed mainly of aliphatic hydrocarbon material that may be protected from, or otherwise unavailable for, degradation. Microbial peptides and carbohydrates were also shown to be important contributors to the C sink and these biomolecules may be from living biomass or preserved necromass. Lignin residues formed only a small part of the OM in the surface sediments but made a greater contribution at depth. Highly ordered components in HU (that resists swelling by dimethylsulfoxide, DMSO) play a major role in C sequestration

    Spallation reactions. A successful interplay between modeling and applications

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    The spallation reactions are a type of nuclear reaction which occur in space by interaction of the cosmic rays with interstellar bodies. The first spallation reactions induced with an accelerator took place in 1947 at the Berkeley cyclotron (University of California) with 200 MeV deuterons and 400 MeV alpha beams. They highlighted the multiple emission of neutrons and charged particles and the production of a large number of residual nuclei far different from the target nuclei. The same year R. Serber describes the reaction in two steps: a first and fast one with high-energy particle emission leading to an excited remnant nucleus, and a second one, much slower, the de-excitation of the remnant. In 2010 IAEA organized a worskhop to present the results of the most widely used spallation codes within a benchmark of spallation models. If one of the goals was to understand the deficiencies, if any, in each code, one remarkable outcome points out the overall high-quality level of some models and so the great improvements achieved since Serber. Particle transport codes can then rely on such spallation models to treat the reactions between a light particle and an atomic nucleus with energies spanning from few tens of MeV up to some GeV. An overview of the spallation reactions modeling is presented in order to point out the incomparable contribution of models based on basic physics to numerous applications where such reactions occur. Validations or benchmarks, which are necessary steps in the improvement process, are also addressed, as well as the potential future domains of development. Spallation reactions modeling is a representative case of continuous studies aiming at understanding a reaction mechanism and which end up in a powerful tool.Comment: 59 pages, 54 figures, Revie

    Multiple inflammasomes may regulate the interleukin-1-driven inflammation in protracted bacterial bronchitis

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    Protracted bacterial bronchitis (PBB) in young children is characterised by prolonged wet cough, prominent airway interleukin (IL)-1β expression and infection, often with nontypeable Haemophilus influenzae (NTHi). The mechanisms responsible for IL-1-driven inflammation in PBB are poorly understood. We hypothesised that the inflammation in PBB involves the NLRP3 and/or AIM2 inflammasome/IL-1β axis. Lung macrophages obtained from bronchoalveolar lavage (BAL), peripheral blood mononuclear cells (PBMCs), blood monocytes and monocyte-derived macrophages from patients with PBB and age-matched healthy controls were cultured in control medium or exposed to live NTHi. In healthy adult PBMCs, CD14+ monocytes contributed to 95% of total IL-1β-producing cells upon NTHi stimulation. Stimulation of PBB PBMCs with NTHi significantly increased IL-1β expression (p<0.001), but decreased NLRC4 expression (p<0.01). NTHi induced IL-1β secretion in PBMCs from both healthy controls and patients with recurrent PBB. This was inhibited by Z-YVAD-FMK (a caspase-1 selective inhibitor) and by MCC950 (a NLRP3 selective inhibitor). In PBB BAL macrophages inflammasome complexes were visualised as fluorescence specks of NLRP3 or AIM2 colocalised with cleaved caspase-1 and cleaved IL-1β. NTHi stimulation induced formation of specks of cleaved IL-1β, NLRP3 and AIM2 in PBMCs, blood monocytes and monocyte-derived macrophages. We conclude that both the NLRP3 and AIM2 inflammasomes probably drive the IL-1β-dominated inflammation in PBB.Alice C-H. Chen, Hai B. Tran, Yang Xi, Stephanie T. Yerkovich, Katherine J. Baines, Susan J. Pizzutto, Melanie Carroll, Avril A.B. Robertson, Matthew A. Cooper, Kate Schroder, Jodie L. Simpson, Peter G. Gibson, Greg Hodge, Ian B. Masters, Helen M. Buntain, Helen L. Petsky, Samantha J. Prime, Anne B. Chang, Sandra Hodge, and John W. Upha

    The Sudbury Neutrino Observatory

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    The Sudbury Neutrino Observatory is a second generation water Cherenkov detector designed to determine whether the currently observed solar neutrino deficit is a result of neutrino oscillations. The detector is unique in its use of D2O as a detection medium, permitting it to make a solar model-independent test of the neutrino oscillation hypothesis by comparison of the charged- and neutral-current interaction rates. In this paper the physical properties, construction, and preliminary operation of the Sudbury Neutrino Observatory are described. Data and predicted operating parameters are provided whenever possible.Comment: 58 pages, 12 figures, submitted to Nucl. Inst. Meth. Uses elsart and epsf style files. For additional information about SNO see http://www.sno.phy.queensu.ca . This version has some new reference

    A importância da associação obesidade e gravidez

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    Characteristics of the evolution of pregnancy in obese women were studied for their effect on newborn infants. Two control groups were observed - one of normal weight pregnant women, one of obese. The variables selected were: the socio-economic status of the family and the mother's age, height, arm circunference, prepregancy weight, total number of pregnancies, parity, weight gain during pregnancy, obstetric complications, birth weight, and fetal vitality. Results showed that pregnancy in obese women differs from that in normal weight women and that they show a larger incidence of obstetric complications. Children of obese mothers had a higher mortality rate principally in the perinatal period; moreover, there was also a higher rate of prematurity and a higher proportion of overweight babies among obese mothers. As a result, the distribution of the curve of the birth weight of infants of obese morthers was higher than that of infants of normal weight mothers. The conclusion reached was that whenever a pregnant obese woman reduced foot intake, with resultant insufficient weight gain, intrauterine growth was affected. Thus, it follows that pregnancy is not the best time for the obese mother to lose weight; for this reason, it is important that she receive adequate guidance in regard to diet. Obesity, therefore, is a factor contributing to high-risk pregnancy which can affect both mother and child.Foram estudados dois grupos de gestantes, sendo um de grávidas normais e outro de obesas, com a finalidade de reconhecer algumas características da evolução da gravidez, em mulheres obesas, e suas repercussões sobre o concepto. Foram relacionadas as seguintes variáveis: status sócio-econômico familiar, idade, altura, perímetro braquial, peso habitual, número de gestações anteriores, paridade materna, ganho de peso durante a gestação, idade gestacional, intercorrências durante a gestação, peso ao nascer e vitalidade do recém-nascido. Pelos resultados concluiu-se que as gestantes obesas são diferentes das normais e apresentam maior incidência de complicações obstétricas. Os recém-nascidos, filhos de obesas, registraram índice maior de mortalidade, principalmente no período perinatal. Houve maior incidência de prematuridade e de fetos macrossômicos, sendo a curva de distribuição de peso ao nascer diferente da dos recém-nascidos das gestantes normais. A média de peso ao nascer das crianças das gestantes obesas é maior que o das normais. Concluiu-se ainda que toda vez que a gestante obesa sofre restrição alimentar, com ganho de peso inadequado, o crescimento intra-uterino é afetado; não sendo, portanto, a época da gravidez a melhor para a obesa perder peso, mas, ao contrário, ela deveria receber uma orientação alimentar adequada. A obesidade é pois um fator de aumento do risco gravídico, que pode afetar tanto a mãe como o concepto

    Zarządzanie i handel zagraniczny w małych i średnich przedsiębiorstwach w warunkach integracji europejskiej: materiały z konferencji

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    Z przedmowy: "Integracja europejska to proces łączenia, scalania się odrębnych ekonomicznie, społecznie, kulturowo gospodarek europejskich krajów. Proces integracji prowadzi do istotnych przekształceń w sferze gospodarki, strategiach organizacji i funkcjonowania przedsiębiorstw, handlu międzynarodowym, działalności marketingowej, strukturach organizacyjnych i mechanizmach ekonomicznych przedsiębiorstw i instytucji działających w krajach integrujących się. Proces integracji to w praktyce proces dostosowywania się struktur gospodarczych; tworzenia związków kooperacyjno-produkcyjnych; powstawania trwałych więzi ekonomicznych między przedsiębiorstwami integrujących się krajów a więc proces kształtowania jednolitego obszaru gospodarczego z odrębnych a często także wzajemnie konkurencyjnych krajów, gospodarek, regionów, gałęzi, branż. Proces międzynarodowej integracji gospodarczej to w dużej mierze proces tworzenia komplementamości przedsiębiorstw i instytucji, komplementamości międzygałęziowej i wewnątrz gałęziowej, w produkcji i wymianie jak też kształtowanie niezbędnej infrastruktury technicznej i ekonomicznej umożliwiającej tworzenie sytemu trwałych powiązań gospodarczych między poszczególnymi krajami."(...

    Measurement of the νe and total 8B solar neutrino fluxes with the Sudbury Neutrino Observatory phase-III data set

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    This paper details the solar neutrino analysis of the 385.17-day phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of 3He proportional counters was installed in the heavy-water target to measure precisely the rate of neutrino-deuteron neutral-current interactions. This technique to determine the total active 8B solar neutrino flux was largely independent of the methods employed in previous phases. The total flux of active neutrinos was measured to be 5.54-0.31+0.33(stat.)-0.34+0.36(syst.)×106 cm-2 s-1, consistent with previous measurements and standard solar models. A global analysis of solar and reactor neutrino mixing parameters yielded the best-fit values of Δm2=7.59-0.21+0.19×10 -5eV2 and θ=34.4-1.2+1.3degrees

    Freshwater mussels from South America: state of the art of Unionida, specially Rhipidodontini

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