105 research outputs found

    Enhancement of resistivity and magnetization of Bi1-xLaxFe1-yMnyO3 ceramics by composition optimization

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    This work aims at studying the effect of La and Mn substituents on the structural, electrical and magnetic properties of Bi1-xLaxFe1-yMnyO3 (0≤x≤0.30; 0≤y≤0.20) at room temperature, in order to find out the optimal compositions that provide both high resistivity and remnant magnetization. The analysis of the XRD patterns and Raman spectra suggest a progressive transition from a rhombohedral for x0.20. Moreover, we observe satellite peaks associated with an incommensurate modulated (IM) orthorhombic structure for x≥0.15 with y = 0, and x = 0.20 with y = 0.10. We were able to achieve a decrease by several orders of magnitude of the leakage current density and the emergence of a weak ferromagnetic response in the range of compositions 0.10<x≤0.3 and 0<y<0.1. These improved physical properties are a consequence of the absence of secondary phases and the breaking of the spiral cycloid spin structure. In particular, the compositions within 0.18≤x≤0.30 and 0.01<y<0.05 with IM orthorhombic structure exhibit the lowest conductivity and highest remnant magnetization. The outcome of this work suggests an alternative route to enhance multiferroic properties of BiFeO3, with simultaneous La (0.10≤x≤0.30) and moderate Mn (0.01<y<0.1) substitution.publishe

    Marine accidents in the Brazilian Amazon : the problems and challenges in the initiatives for their prevention focused on passenger ships

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    The Brazilian Amazon is part of one of the largest river systems in the world, in which the transport of cargo and passengers is commonplace. However, several accidents still occur to passenger ships, causing fatalities. Transportation occurs commonly in remote regions, where there are transport inequalities, and emergency assistance is hard to find. This can affect sustainability in communities with considerable levels of economic and social vulnerability. More information is needed about accidents involving inland transport in the Amazon, to identify the threats to ships and propose strategies for accident prevention. This paper addresses the main problems that long-distance passenger ships face in the Brazilian Amazon, presenting an integrated framework towards accident prevention. First, the present situation is characterized in terms of ship description, spatial distribution, and regulations that are applicable. Next, possible causes of passenger ship accidents are discussed, including topics of concern that should be considered in the Amazon waterways. Finally, measures to help minimize passenger ship accidents are proposed, and the social relevance is discussed. It was found that accidents in the Amazon are due to a combination of human and environmental factors. Stakeholders should strengthen the technical and legal training of ship operators. The use of new technologies for navigational aid and necessary maintenance of ships is suggested. Marine accident prevention initiatives should consider local conditions, such as environmental preservation, cultural respect, and difficulties related to navigation through the complex riverine system of the Amazon region

    Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

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    Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated

    Rare SLC13A1 variants associate with intervertebral disc disorder highlighting role of sulfate in disc pathology

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    Publisher Copyright: © 2022, The Author(s).Back pain is a common and debilitating disorder with largely unknown underlying biology. Here we report a genome-wide association study of back pain using diagnoses assigned in clinical practice; dorsalgia (119,100 cases, 909,847 controls) and intervertebral disc disorder (IDD) (58,854 cases, 922,958 controls). We identify 41 variants at 33 loci. The most significant association (ORIDD = 0.92, P = 1.6 × 10−39; ORdorsalgia = 0.92, P = 7.2 × 10−15) is with a 3’UTR variant (rs1871452-T) in CHST3, encoding a sulfotransferase enzyme expressed in intervertebral discs. The largest effects on IDD are conferred by rare (MAF = 0.07 − 0.32%) loss-of-function (LoF) variants in SLC13A1, encoding a sodium-sulfate co-transporter (LoF burden OR = 1.44, P = 3.1 × 10−11); variants that also associate with reduced serum sulfate. Genes implicated by this study are involved in cartilage and bone biology, as well as neurological and inflammatory processes.Peer reviewe
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