1,040 research outputs found

    The generation of nonlinear internal waves

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    Author Posting. © The Oceanography Society, 2012. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 25, No. 2 (2012): 108–123, doi:10.5670/oceanog.2012.46.Nonlinear internal waves are found in many parts of the world ocean. Their widespread distribution is a result of their origin in the barotropic tide and in the variety of ways they can be generated, including by lee waves, tidal beams, resonance, plumes, and the transformation of the internal tide. The differing generation mechanisms and diversity of generation locations and conditions all combine to produce waves that range in scale from a few tens of meters to kilometers, but with all properly described by solitary wave theory. The ability of oceanic nonlinear internal waves to persist for days after generation and the key role internal waves play in connecting large-scale tides to smaller-scale turbulence make them important for understanding the ocean environment.Christopher Jackson gratefully acknowledges the support of the Office of Naval Research through contract N0001409C0224

    Statistical analysis of reinforced concrete bridges in Estonia

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    This paper introduces a possible way to use a multivariate methodology, called principal component analysis, to reduce the dimensionality of condition state database of bridge elements, collected during visual inspections. Attention is paid to the condition assessment of bridges in Estonian national roads and collected data, which plays an important role in the selection of correct statistical technique and obtaining reliable results. Additionally, detailed overview of typical road bridges and examples of collected information is provided. Statistical analysis is carried out by most natural reinforced concrete bridges in Estonia and comparison is made among different typologies. The introduced multivariate technique algorithms are presented and collated in two different formulations, with contrast on unevenness in variables and taking into account the missing data. Principal components and weighing factors, which are calculated for bridges with different typology, also have differences in results and element groups where variation is retainedTU1406 – Quality Specifications for Roadway Bridges, standardiza- tion at a European level (BridgeSpec), a COST Action sup- ported by EU Framework Programme Horizon 2020info:eu-repo/semantics/publishedVersio

    Phase transition in a chain of quantum vortices

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    We consider interacting vortices in a quasi-one-dimensional array of Josephson junctions with small capacitance. If the charging energy of a junction is of the order of the Josephson energy, the fluctuations of the superconducting order parameter in the system are considerable, and the vortices behave as quantum particles. Their density may be tuned by an external magnetic field, and therefore one can control the commensurability of the one-dimensional vortex lattice with the lattice of Josephson junctions. We show that the interplay between the quantum nature of a vortex, and the long-range interaction between the vortices leads to the existence of a specific commensurate-incommensurate transition in a one-dimensional vortex lattice. In the commensurate phase an elementary excitation is a soliton, with energy separated from the ground state by a finite gap. This gap vanishes in the incommensurate phase. Each soliton carries a fraction of a flux quantum; the propagation of solitons leads to a finite resistance of the array. We find the dependence of the resistance activation energy on the magnetic field and parameters of the Josephson array. This energy consists of the above-mentioned gap, and also of a boundary pinning term, which is different in the commensurate and incommensurate phases. The developed theory allows us to explain quantitatively the available experimental data.Comment: 14 pages, 7 eps figure

    Evolving minimum standards in responsible international sperm donor offspring quota

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    An international working group was established with the aim of making recommendations on the number of offspring for a sperm donor that should be allowable in cases of international use of his sperm. Considerations from genetic, psychosocial, operational and ethical points of view were debated. For these considerations, it was assumed that current developments in genetic testing and Internet possibilities mean that, now, all donors are potentially identifiable by their offspring, so no distinction was made between anonymous and non-anonymous donation. Genetic considerations did not lead to restrictive limits (indicating that up to 200 offspring or more per donor may be acceptable except in isolated social-minority situations). Psychosocial considerations on the other hand led to proposals of rather restrictive limits (10 families per donor or less). Operational and ethical considerations did not lead to more or less concrete limits per donor, but seemed to lie in-between those resulting from the aforementioned ways of viewing the issue. In the end, no unifying agreed figure could be reached; however the consensus was that the number should never exceed 100 families. The conclusions of the group are summarized in three recommendation

    RNase H2, mutated in Aicardi-Goutières syndrome, promotes LINE-1 retrotransposition

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    Long INterspersed Element class 1 (LINE-1) elements are a type of abundant retrotransposons active in mammalian genomes. An average human genome contains ~100 retrotransposition-competent LINE-1s, whose activity is influenced by the combined action of cellular repressors and activators. TREX1, SAMHD1 and ADAR1 are known LINE-1 repressors and when mutated cause the autoinflammatory disorder Aicardi-Goutières syndrome (AGS). Mutations in RNase H2 are the most common cause of AGS, and its activity was proposed to similarly control LINE-1 retrotransposition. It has therefore been suggested that increased LINE-1 activity may be the cause of aberrant innate immune activation in AGS. Here, we establish that, contrary to expectations, RNase H2 is required for efficient LINE-1 retrotransposition. As RNase H1 overexpression partially rescues the defect in RNase H2 null cells, we propose a model in which RNase H2 degrades the LINE-1 RNA after reverse transcription, allowing retrotransposition to be completed. This also explains how LINE-1 elements can retrotranspose efficiently without their own RNase H activity. Our findings appear to be at odds with LINE-1-derived nucleic acids driving autoinflammation in AGS.M.B.-G. is funded by a “Formacion Profesorado Universitario” (FPU) PhD fellowship from the Government of Spain (MINECO, Ref FPU15/03294), and this paper is part of her thesis project (“Epigenetic control of the mobility of a human retrotransposon”). R.V.-A. is funded by a PFIS Fellowship from the Government of Spain (ISCiii, FI16/00413). O.M. is funded by an EMBO Long-Term Fellowship (ALTF 7-2015), the European Commission FP7 (Marie Curie Actions, LTFCOFUND2013, GA-2013-609409) and the Swiss National Science Foundation (P2ZHP3_158709). S.R.H. is funded by the Government of Spain (MINECO, RYC-2016-21395 and SAF2015-71589-P). A.P.J’s laboratory is supported by the UK Medical Research Council (MRC University Unit grant U127527202). J.L.G.P’s laboratory is supported by CICEFEDER- P12-CTS-2256, Plan Nacional de I+D+I 2008-2011 and 2013-2016 (FISFEDER- PI14/02152), PCIN-2014-115-ERA-NET NEURON II, the European Research Council (ERC-Consolidator ERC-STG-2012-233764), by an International Early Career Scientist grant from the Howard Hughes Medical Institute (IECS-55007420), by The Wellcome Trust-University of Edinburgh Institutional Strategic Support Fund (ISFF2) and by a private donation from Ms Francisca Serrano (Trading y Bolsa para Torpes, Granada, Spain)

    The MINDVIEW project: First results

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    [EN] We present the first results of the MINDVIEW project. An innovative imaging system for the human brain examination, allowing simultaneous acquisition of PET/MRI images, has been designed and constructed. It consists of a high sensitivity and high resolution PET scanner integrated in a novel, head-dedicated, radio frequency coil for a 3T MRI scanner. Preliminary measurements from the PET scanner show sensitivity 3 times higher than state-of-the-art PET systems that will allow safe repeated studies on the same patient. The achieved spatial resolution, close to 1 mm, will enable differentiation of relevant brain structures for schizophrenia. A cost-effective and simple method of radiopharmaceutical production from C-11-carbon monoxide and a mini-clean room has been demonstrated. It has been shown that C-11-raclopride has higher binding potential in a new VAAT null mutant mouse model of schizophrenia compared to wild type control animals. A significant reduction in TSPO binding has been found in gray matter in a small sample of drug-naive, first episode psychosis patients, suggesting a reduced number or an altered function of immune cells in brain at early stage schizophrenia. (c) 2018 Elsevier Masson SAS. All rights reserved.This project is funded by EU grant FP7-HEALTH-F2-2013-603002.Benlloch Baviera, JM.; González Martínez, AJ.; Pani, R.; Preziosi, E.; Jackson, C.; Murphy, J.; Barbera Ballester, J.... (2018). The MINDVIEW project: First results. European Psychiatry. 50:21-27. https://doi.org/10.1016/j.eurpsy.2018.01.002S212750Gonzalez, A. J., Gonzalez-Montoro, A., Aguilar, A., Conde, P., Canizares, G., Hernandez, L., … Benlloch, J. M. (2016). A brain PET insert MR compatible: Final design and first results. 2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD). doi:10.1109/nssmic.2016.8069619Dahl, K., Schou, M., Ulin, J., Sjöberg, C.-O., Farde, L., & Halldin, C. (2015). 11C-carbonylation reactions using gas–liquid segmented microfluidics. RSC Advances, 5(108), 88886-88889. doi:10.1039/c5ra20646d[26] Långström B and Sjöberg CO, System for controlling environment in reaction box, From PCT Int. Appl. (2013), WO 2013103312 A1 20130711.Autret, A., Bert, J., Strauss, O., & Visvikis, D. (2012). 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Journal of Psychopharmacology, 29(2), 97-115. doi:10.1177/0269881114563634Moliner, L., Correcher, C., González, A. J., Conde, P., Hernández, L., Orero, A., … Benlloch, J. M. (2013). Implementation and analysis of list mode algorithm using tubes of response on a dedicated brain and breast PET. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 702, 129-132. doi:10.1016/j.nima.2012.08.029Zelano, J., Mikulovic, S., Patra, K., Kühnemund, M., Larhammar, M., Emilsson, L., … Kullander, K. (2013). The synaptic protein encoded by the gene Slc10A4 suppresses epileptiform activity and regulates sensitivity to cholinergic chemoconvulsants. Experimental Neurology, 239, 73-81. doi:10.1016/j.expneurol.2012.09.006Antich, P., Malakhov, N., Parkey, R., Slavin, N., & Tsyganov, E. (2002). 3D position readout from thick scintillators. 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    Acute Progression of BCR-FGFR1 Induced Murine B-Lympho/Myeloproliferative Disorder Suggests Involvement of Lineages at the Pro-B Cell Stage

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    Constitutive activation of FGFR1, through rearrangement with various dimerization domains, leads to atypical myeloproliferative disorders where, although T cell lymphoma are common, the BCR-FGFR1 chimeric kinase results in CML-like leukemia. As with the human disease, mouse bone marrow transduction/transplantation with BCR-FGFR1 leads to CML-like myeloproliferation as well as B-cell leukemia/lymphoma. The murine disease described in this report is virtually identical to the human disease in that both showed bi-lineage involvement of myeloid and B-cells, splenomegaly, leukocytosis and bone marrow hypercellularity. A CD19+ IgM− CD43+ immunophenotype was seen both in primary tumors and two cell lines derived from these tumors. In all primary tumors, subpopulations of these CD19+ IgM− CD43+ were also either B220+ or B220−, suggesting a block in differentiation at the pro-B cell stage. The B220− phenotype was retained in one of the cell lines while the other was B220+. When the two cell lines were transplanted into syngeneic mice, all animals developed the same B-lymphoblastic leukemia within 2-weeks. Thus, the murine model described here closely mimics the human disease with bilineage myeloid and B-cell leukemia/lymphoma which provides a representative model to investigate therapeutic intervention and a better understanding of the etiology of the disease
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