815 research outputs found

    The preburning condition of Chalcolithic cremated human remains from the Perdigoes enclosures (Portugal)

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    The Iberian Chalcolithic displayed a remarkable variety of funerary practices, which has been related to interpopulation differences, intrapopulation social-cultural differences, and complex multistage funerary rituals. Perdigoes, a Chalcolithic set of ditched enclosures, reflects such diversity including a wide array of funerary practices. Among those practices is cremation, which, despite relatively rare, is represented in different structures in Perdigoes. One of these structures (Pit 40) presents an unparalleled high minimum number of individuals (n = 240), contrasting with nearby and coeval structures. In this study, we analyse heat-induced bone changes and other archaeothanatological variables to tentatively assess the preburning condition of the human remains. The results of Pit 40 are also compared with other comparable contexts to assess if this unique context presents further funerary differences relative to those other contexts in, for example, body processing. Our results suggest preferential cremation of fleshed human remains, but burning of at least a minority of skeletonised remains and deposition of possibly unburned remains also likely occurred. Body processing appears to be comparable with that of the cremation contexts of Perdigoes but contrasts with that of another nearby context (Dolmen of Olival da Pega 2b) in which burned bones were also found.Portuguese Foundation for Science and TechnologyPortuguese Foundation for Science and Technology [PEst-OE/SADG/UI0283/2013, POCI-01-0145-FEDER-016766, PTDC/EPH-ARQ/0798/2014, PTDC/IVC-ANT/1201/2014, SFRH/BPD/84268/2012]info:eu-repo/semantics/publishedVersio

    Data acquisition software for the CMS strip tracker

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    The CMS silicon strip tracker, providing a sensitive area of approximately 200 m2 and comprising 10 million readout channels, has recently been completed at the tracker integration facility at CERN. The strip tracker community is currently working to develop and integrate the online and offline software frameworks, known as XDAQ and CMSSW respectively, for the purposes of data acquisition and detector commissioning and monitoring. Recent developments have seen the integration of many new services and tools within the online data acquisition system, such as event building, online distributed analysis, an online monitoring framework, and data storage management. We review the various software components that comprise the strip tracker data acquisition system, the software architectures used for stand-alone and global data-taking modes. Our experiences in commissioning and operating one of the largest ever silicon micro-strip tracking systems are also reviewed

    The qualification of collective absolutes and the individuality of persons and events in mid-nineteenth-century Spain

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    This article argues, on the basis of intellectual, literary, and art history, against the view that mid-nineteenth-century notions of individuality in Spain were products of a social structure based around a bourgeoisie, or, in other accounts, based around a failed effort to establish a bourgeoisie. Instead, it argues that an emphasis on individuality could take radically different forms, that there was no core shared idea of 'individuality'. The article argues that the key motivating factor in these varying notions of individuality was a conflict between and concerning different factions within an oligarchic elite over the future of that elite

    Tensor Regression with Applications in Neuroimaging Data Analysis

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    Classical regression methods treat covariates as a vector and estimate a corresponding vector of regression coefficients. Modern applications in medical imaging generate covariates of more complex form such as multidimensional arrays (tensors). Traditional statistical and computational methods are proving insufficient for analysis of these high-throughput data due to their ultrahigh dimensionality as well as complex structure. In this article, we propose a new family of tensor regression models that efficiently exploit the special structure of tensor covariates. Under this framework, ultrahigh dimensionality is reduced to a manageable level, resulting in efficient estimation and prediction. A fast and highly scalable estimation algorithm is proposed for maximum likelihood estimation and its associated asymptotic properties are studied. Effectiveness of the new methods is demonstrated on both synthetic and real MRI imaging data.Comment: 27 pages, 4 figure

    Transcriptional and Translational Regulatory Responses to Iron Limitation in the Globally Distributed Marine Bacterium Candidatus Pelagibacter ubique

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    Iron is recognized as an important micronutrient that limits microbial plankton productivity over vast regions of the oceans. We investigated the gene expression responses of Candidatus Pelagibacter ubique cultures to iron limitation in natural seawater media supplemented with a siderophore to chelate iron. Microarray data indicated transcription of the periplasmic iron binding protein sfuC increased by 16-fold, and iron transporter subunits, iron-sulfur center assembly genes, and the putative ferroxidase rubrerythrin transcripts increased to a lesser extent. Quantitative peptide mass spectrometry revealed that sfuC protein abundance increased 27-fold, despite an average decrease of 59% across the global proteome. Thus, we propose sfuC as a marker gene for indicating iron limitation in marine metatranscriptomic and metaproteomic ecological surveys. The marked proteome reduction was not directly correlated to changes in the transcriptome, implicating post-transcriptional regulatory mechanisms as modulators of protein expression. Two RNA-binding proteins, CspE and CspL, correlated well with iron availability, suggesting that they may contribute to the observed differences between the transcriptome and proteome. We propose a model in which the RNA-binding activity of CspE and CspL selectively enables protein synthesis of the iron acquisition protein SfuC during transient growth-limiting episodes of iron scarcity

    The population genomics of archaeological transition in west Iberia: Investigation of ancient substructure using imputation and haplotype-based methods

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    We analyse new genomic data (0.05–2.95x) from 14 ancient individuals from Portugal distributed from the Middle Neolithic (4200–3500 BC) to the Middle Bronze Age (1740–1430 BC) and impute genomewide diploid genotypes in these together with published ancient Eurasians. While discontinuity is evident in the transition to agriculture across the region, sensitive haplotype-based analyses suggest a significant degree of local hunter-gatherer contribution to later Iberian Neolithic populations. A more subtle genetic influx is also apparent in the Bronze Age, detectable from analyses including haplotype sharing with both ancient and modern genomes, D-statistics and Y-chromosome lineages. However, the limited nature of this introgression contrasts with the major Steppe migration turnovers within third Millennium northern Europe and echoes the survival of non-Indo-European language in Iberia. Changes in genomic estimates of individual height across Europe are also associated with these major cultural transitions, and ancestral components continue to correlate with modern differences in stature

    Premixed methane oxycombustion in nitrogen and carbon dioxide atmospheres: measurement of operating limits, flame location and emissions. Proceedings of the Combustion Institute

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    AbstractThe influence of O2 concentration on a premixed swirling flame was investigated for changes in discrete levels of CO2 and N2 dilution, with application to carbon capture in gas turbine systems. Chemical kinetic models were utilised to support and analyse generic burner experiments at 37.5kW. O2 mole fraction in the oxygen-diluent stream was varied between 0.21 and 0.70 and careful measurement of velocity field data using particle image velocimetry, representative heat release (OH* chemiluminescence) and flame location (OH planar laser-induced fluorescence) was undertaken. Results show that under lean N2-diluted operating conditions there is a minor change in burner operation for all O2 concentrations considered. CO2 dilution has a far more substantial impact than N2 on flame location, heat release and operational response, which is attributed to the fundamental differences in thermodynamic and transport properties between the two gases. This also resulted in increased CO concentrations sampled from the exhaust stream with a rise in diluent CO2, which is attributed to lower flame temperatures as opposed to thermal dissociation, whilst increased N2 dilution resulted in increasing NOX emissions

    Dissociative influence of H2O vapour/spray on lean blowoff and NOx reduction for heavily carbonaceous syngas swirling flames

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    Recent studies have described and evidenced the enhancement of fundamental combustion parameters such as laminar flame speed due to the catalytic influence of H2O with heavily carbonaceous syngas mixtures. In this study, the potential benefits of these subtle changes in water loading and hence reaction pathways are explored in terms of delayed lean blowoff, and primary emission reduction in a premixed turbulent swirling flame (Ø = 0.6–0.8), scaled for practical relevance. Chemical kinetic models initially confirm that H2O has a substantial impact on the employed fuel behaviour; increasing flame speed by up to 60% across an experimental range representative of fluctuation in atmospheric humidity (∼1.8 mol%). OH* chemiluminescence and OH planar laser induced fluorescence (PLIF) were employed to analyse the changes in heat release structure resulting from the experimental addition of H2O vapour to the combustor. Equivalent concentrations of liquid H2O were introduced into the central recirculation zone of the premixed flame as an atomised spray, to investigate the influence of phase changes on the catalytic effect. Near the lean stability limit, H2O addition compresses heat release to shorten the elongated flame structure. Whereas with a stable and well-defined flame structure, the addition triggers a change in axial heat release location, causing the flame front to retract upstream toward the burner outlet. Higher quantities of two-phase flow were combined to explore the possibility of employing the spray as a stabilising mechanism, effectively dampening the observed influence of humidity. The chemical enhancement induced by the controlled supply was shown to reduce the lean blowoff stability limit, enabling an increase in additional air flow of almost 10%. However, the catalytic effect of H2O diminishes with excessive supply and thermal quenching prevails. There is a compound benefit of NOx reduction from the use of H2O as a flame stabiliser with the practically-relevant syngas: First NOx production decreases due to thermal effect of H2O addition, with potential for further reduction from the change in lean stability limit; leanest experimental concentrations reduced by up to a factor of four with two-phase flow at the highest rates of supply. Hence, the catalytic effect of H2O on reaction pathways and reaction rate predicted and observed in the laminar environment, is shown to translate into practical benefits in the challenging environment of turbulent, swirl-stabilised flames
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