1,086 research outputs found

    Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

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    27 pages, 12 figures, 13 tablesMolecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound-specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean) were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the organic matter (OM) of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and 80%), with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%), whereas those from the slope contained the highest proportion of fossil (40%) and C3 terrestrial plant material (10%). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low compared to other studies conducted 5–20 yr earlier, and they support the increase in primary production during the last decade mainly because of the increase in the number of ice-free days and due to the strength and persistence of winds favouring upwellingThe IAEA is grateful for the support provided to the Environment Laboratories by the Government of the Principality of Monaco. This study was conducted as part of the Malina Scientific Program funded by ANR (Agence nationale de la recherche), INSU-CNRS (Institut national des sciences de l’univers – Centre national de la recherche scientifique), CNES (Centre national d’etudes spatiales) and ESA (European Space Agency). The authors would like to thank M. Babin, chief scientist of the cruise and coordinator of the Malina program, A. Forest, H. Link and G. Chaillou and three anonymous reviewers for their constructive commentsPeer reviewe

    Dynamic nuclear polarization enhanced solid-state NMR studies of surface modification of gamma-alumina

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    Dynamic nuclear polarization (DNP) gives large (>100-fold) signal enhancements in solid-state NMR spectra via the transfer of spin polarization from unpaired electrons from radicals implanted in the sample. This means that the detailed information about local molecular environment available for bulk samples from solid-state NMR spectroscopy can now be obtained for dilute species, such as sites on the surfaces of catalysts and catalyst supports. In this paper we describe a DNP-enhanced solid-state NMR study of the widely used catalyst gamma-alumina which is often modified at the surface by the incorporation of alkaline earth oxides in order to control the availability of catalytically active penta-coordinate surface Al sites. DNP-enhanced 27Al solid-state NMR allows surface sites in gamma-alumina to be observed and their 27Al NMR parameters measured. In addition changes in the availability of different surface sites can be detected after incorporation of BaO

    Pramipexole for the treatment of depressive symptoms in patients with Parkinson disease: a randomized, double blind, placebo controlled trial

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    Background: Depression is common in patients with Parkinson's disease, but evidence on the efficacy of antidepressants in this population is lacking. Because depression in patients with Parkinson's disease might be related to dopaminergic dysfunction, we aimed to assess the efficacy of the dopamine agonist pramipexole for treatment of depressive symptoms in patients with Parkinson's disease. METHODS: We did a 12-week randomised, double-blind, placebo-controlled (1:1 ratio) trial of pramipexole (0.125-1.0 mg three times per day) compared with placebo in patients with mild-to-moderate Parkinson's disease. Patients from 76 centres in 12 European countries and South Africa were included if they were on stable antiparkinsonian therapy without motor fluctuations and had depressive symptoms (15-item geriatric depression scale score > or =5 and unified Parkinson's disease rating scale [UPDRS] part 1 depression item score > or =2). Patients were randomly assigned by centre in blocks of four by use of a randomisation number generating system. Clinical monitors, the principal investigator, and patients were masked to treatment allocation. The primary endpoint was change in Beck depression inventory (BDI) score and all treated patients who had at least one post-baseline efficacy assessment were included in the primary analysis. We also did a pre-specified path analysis with regression models to assess the relation between BDI and UPDRS part 3 (motor score) changes. This trial is registered with ClinicalTrials.gov, number NCT00297778, and EudraCT, number 2005-003788-22. FINDINGS: Between March, 2006, and February, 2008, we enrolled 323 patients. Of 296 patients randomly assigned to pramipexole or placebo, 287 were included in the primary analysis: 139 in the pramipexole group and 148 in the placebo group. BDI scores decreased by an adjusted mean 5.9 (SE 0.5) points in the pramipexole group and 4.0 (0.5) points in the placebo group (difference 1.9, 95% CI 0.5-3.4; p=0.01, ANCOVA). The UPDRS motor score decreased by an adjusted mean 4.4 (0.6) points in the pramipexole group and 2.2 (0.5) points in the placebo group (difference 2.2, 95% CI 0.7-3.7; p=0.003, ANCOVA). Path analysis showed the direct effect of pramipexole on depressive symptoms accounted for 80% of total treatment effect (p=0.04). Adverse events were reported in 105 of 144 patients in the pramipexole group and 101 of 152 in the placebo group. Adverse events in the pramipexole group were consistent with the known safety profile of the drug. INTERPRETATION: Pramipexole improved depressive symptoms in patients with Parkinson's disease, mainly through a direct antidepressant effect. This effect should be considered in the clinical management of patients with Parkinson's disease

    Fate of Irgarol 1051, diuron and their main metabolites in two UK marine systems after restrictions in antifouling paints

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    Two major antifouling biocides used worldwide, Irgarol 1051 and diuron, and their degradation products in Shoreham Harbour and Brighton Marina, UK were studied during 2003-2004. The highest concentrations of Irgarol 1051 were 136 and 102 ng L(-1) in water and 40 and 49 ng g(-1) dry weight in sediments for Shoreham Harbour and Brighton Marina, respectively. As the degradation product of Irgarol 1051, M1 was also widespread, with the highest concentration of 59 ng L(-1) in water and 23 ng g(-1) in sediments in Shoreham Harbour, and 37 ng L(-1) in water and 5.6 ng g(-1) in sediments in Brighton Marina. The target compounds showed enhanced concentrations during the boating season (May-July), when boats were being re-painted (January-February), and where the density of pleasure crafts was high. Overall, the concentration of Irgarol 1051 decreased significantly from late 2000 to early 2004, indicating the effectiveness of controlling its concentrations in the marine environment following restricted use. Diuron was only detected in 14% of water samples, and mostly absent from sediment samples

    Effect of drying and/or warming piglets at birth on rectal temperature over the first 24 h after birth

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    Piglets experience a rapid decrease in body temperature immediately after birth, increasing the risk of mortality. The objective of this study was to determine the effect of drying and/or warming piglets at birth on rectal temperature over the first 24 h after birth. The study was carried out at a commercial sow facility using a completely randomized design with four treatments (applied to piglets at birth): Control (no drying or warming), Desiccant (dried using a desiccant), Warming Box (placed in a box under a heat lamp for 30 min), and Desiccant + Warming Box (both dried and warmed as above). Farrowing pens had one heat lamp, temperatures under which were similar to the warming box (35 °C). A total of 68 litters (866 piglets) were randomly allotted to a treatment at the birth of the first piglet. At birth, each piglet was identified with a numbered ear tag and weighed; rectal temperature was measured at 0, 10, 20, 30, 45, 60, 120, and 1,440 min after birth. Data were analyzed using a repeated-measures model using PROC MIXED of SAS. Litter was the experimental unit, piglet was a subsample of the litter; and the model included the fixed effects of treatment, time (the repeated measure), and the interaction. Rectal temperatures at birth and 1,440 min after birth were similar (P \u3e 0.05) for all treatments. At all times between 10 and 120 min after birth, Control piglets had lower (P ≤ 0.05) temperatures than the other three treatments. The Desiccant and Warming Box treatments had similar (P \u3e 0.05) temperatures at most measurement times, but the Desiccant + Warming Box treatment had the highest (P ≤ 0.05) rectal temperatures at most times between 10 and 60 min. In addition, for all treatments, light (\u3c1.0 kg) birth weight piglets had lower (P ≤ 0.05) temperatures than medium (1.0–1.5 kg) or heavy (\u3e1.5 kg) piglets at all times between 10 and 120 min. In addition, at these measurement times, the deviation in temperature between the Control and the other three treatments was greater for light than medium or heavy piglets. In conclusion, both drying and warming piglets at birth significantly increased rectal temperatures between 10 and 120 min after birth, with the combination of the two interventions having the greatest effect, especially for low birth weight piglets

    Common variable immunodeficiency, impaired neurological development and reduced numbers of T regulatory cells in a 10-year-old boy with a STAT1 gain-of-function mutation

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    Recently, gain-of-function (GOF) mutations in the gene encoding signal transducer and activator of transcription 1 (STAT1) have been associated with chronic mucocutaneous candidiasis (CMC). This case report describes a 10-year-old boy presenting with signs of common variable immunodeficiency (CVID), failure to thrive, impaired neurological development, and a history of recurrent mucocutaneous Candida infections. Sequencing of the STAT1 gene identified a heterozygous missense mutation in exon 7 encoding the STAT1 coiled-coil domain (c.514T > C, p.Phe172Leu). In addition to hypogammaglobulinemia with B-cell deficiency, and a low percentage of Th17 cells, immunological analysis of the patient revealed a marked depletion of forkhead-box P3+-expressing regulatory T cells (Tregs). In vitro stimulation of T cells from the patient with interferon-α (IFNα) and/or IFNɣ resulted in a significantly increased expression of STAT1-regulated target genes such as MIG1, IRF1, MX1, MCP1/CCL2, IFI-56K, and CXCL10 as compared to IFN-treated cells from a healthy control, while no IFNα/ɣ-mediated up-regulation of the FOXP3 gene was found. These data demonstrate that the STAT1 GOF mutation F172L, which results in impaired stability of the antiparallel STAT1 dimer conformation, is associated with inhibited Treg cell development and neurological symptoms

    El impacto de la escuela media sobre la desigualdad de resultados entre estudiantes argentinos en PISA 2009. Una aplicación multinivel en presencia de heterogeneidad

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    El estudio de la contribución relativa de las características escolares, personales y familiares a la explicación del rendimiento del alumno presenta dificultades metodológicas relacionadas al carácter anidado de los datos y a la presencia de heterogeneidad en las relaciones existentes entre los factores observables y el puntaje obtenido. Este trabajo utiliza los datos de la prueba de lectura de PISA 2009 para Argentina y aplica para su estudio el método multinivel por cuantiles recientemente propuesto en Geraci y Bottai. Los resultados confirman la diferente importancia que asume la escuela en la explicación de los resultados de la prueba de lectura a lo largo de la distribución de puntajes.http://www.aaep.org.arFil: Coseani, Guillermo A. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas. Instituto de Economía y Finanzas; Argentina.Fil: Tolosa, Natalia S. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas. Instituto de Economía y Finanzas; Argentina.Fil: Gertel, Héctor R. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas. Instituto de Economía y Finanzas; Argentina.Economía, Econometrí
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