6,778 research outputs found

    Rural children are more likely to live in cohabiting-couple households

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    As cohabiting increases nationwide, new data show that the growing rate of children in these households is most pronounced in rural areas. This brief analyzes recent U.S. Census Bureau data to explore these trends and patterns

    Spatio-temporal bivariate statistical models for atmospheric trace-gas inversion

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    Atmospheric trace-gas inversion refers to any technique used to predict spatial and temporal fluxes using mole-fraction measurements and atmospheric simulations obtained from computer models. Studies to date are most often of a data-assimilation flavour, which implicitly consider univariate statistical models with the flux as the variate of interest. This univariate approach typically assumes that the flux field is either a spatially correlated Gaussian process or a spatially uncorrelated non-Gaussian process with prior expectation fixed using flux inventories (e.g., NAEI or EDGAR in Europe). Here, we extend this approach in three ways. First, we develop a bivariate model for the mole-fraction field and the flux field. The bivariate approach allows optimal prediction of both the flux field and the mole-fraction field, and it leads to significant computational savings over the univariate approach. Second, we employ a lognormal spatial process for the flux field that captures both the lognormal characteristics of the flux field (when appropriate) and its spatial dependence. Third, we propose a new, geostatistical approach to incorporate the flux inventories in our updates, such that the posterior spatial distribution of the flux field is predominantly data-driven. The approach is illustrated on a case study of methane (CH4_4) emissions in the United Kingdom and Ireland.Comment: 39 pages, 8 figure

    Strain hardening fiber reinforced cement composites for the flexural strengthening of masonry elements of ancient structures

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    To assess the strengthening ability of a strain hardening cementitious composite (SHCC), a layer of SHCC was applied to masonry beams subjected to bending. When compared to the strengthening performance of steel fibre reinforced self-compacting concrete (SFRSCC) layer for this type of brittle beams, the SHCC presented better workability in fresh state, and provided a higher load carrying capacity and deflection ductility even with a smaller layer thickness. By using the data derived from the experimental tests with the constituent materials of the strengthened masonry beams, the behaviour of the tested strengthened masonry beams was numerically simulated with good accuracy.The study presented in this paper is a part of the research Project titled "PrePam - Pre-fabricated thin panels using advanced materials for structural rehabilitation" with reference number of PTDC/ECM/114511/2009 supported by FCT. It is also conducted as part of the MSC-SAHC Master's program supported by the European Commission. The authors also thank the collaboration of the following companies: Sika for providing the sand, Grace for the superplasticizers, Dow for the viscosity modification agents, ENDE-SA Compostilla power station for the fly ash, and SECIL for supplying the cement. The first author acknowledge the PhD grant SFRH/BD/65663/2009 provided by FCT

    Effects of Long-Term Hypoxia on Enzymes of Carbohydrate Metabolism in the Gulf killifish, Fundulus grandis

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    The goal of the current study was to generate a comprehensive, multi-tissue perspective of the effects of chronic hypoxic exposure on carbohydrate metabolism in the Gulf killifish Fundulus grandis. Fish were held at approximately 1.3·mg·l–1 dissolved oxygen (~3.6·kPa) for 4·weeks, after which maximal activities were measured for all glycolytic enzymes in four tissues (white skeletal muscle, liver, heart and brain), as well as for enzymes of glycogen metabolism (in muscle and liver) and gluconeogenesis (in liver). The specific activities of enzymes of glycolysis and glycogen metabolism were strongly suppressed by hypoxia in white skeletal muscle, which may reflect decreased energy demand in this tissue during chronic hypoxia. In contrast, several enzyme specific activities were higher in liver tissue after hypoxic exposure, suggesting increased capacity for carbohydrate metabolism. Hypoxic exposure affected fewer enzymes in heart and brain than in skeletal muscle and liver, and the changes were smaller in magnitude, perhaps due to preferential perfusion of heart and brain during hypoxia. The specific activities of some gluconeogenic enzymes increased in liver during long-term hypoxic exposure, which may be coupled to increased protein catabolism in skeletal muscle. These results demonstrate that when intact fish are subjected to prolonged hypoxia, enzyme activities respond in a tissue-specific fashion reflecting the balance of energetic demands, metabolic role and oxygen supply of particular tissues. Furthermore, within glycolysis, the effects of hypoxia varied among enzymes, rather than being uniformly distributed among pathway enzymes

    Achieving Graduate Attributes through Authentic Learning: The Case of Student Managed Funds

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    According to the Department of Education and Skills (2011), as cited by Murphy and Whelan (2016), there has been a growing emphasis on the importance of graduate attributes in higher education in Ireland. This not only places emphasis on the application of disciplinary specific knowledge, but also on the ‘soft skills’ highly sought by employers. By providing an authentic learning environment, higher education institutes can facilitate the development of graduate attributes while also ensuring graduates are gaining disciplinary specific knowledge. This project explores how Student Managed Funds (SMFs) represent an authentic learning experience through which students achieve a range of graduate attributes. In addition to the literature review that follows, we also provide details of the recently established Technological University Dublin (DIT) Student Managed Fund (SMF) and a step-by-by guide to the establishment of an SMF, whilst also showing how the DIT SMF learning experience maps to the DIT graduate attributes. Finally, we have developed an infographic that summarises how SMFs are authentic learning experiences that achieve graduate attributes and provide tips for practitioners wishing to set-up an SMF

    Flexural strengthening of masonry members using advanced cementitious materials

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    Two different cement based fiber reinforced composites for the flexural strengthening of masonry beams under monotonic loading are studied. Steel Fiber Reinforced Self- Compacting Concrete (SFRSCC) with tensile strain-softening behavior, and PVA fiber reinforced cement based mortar (SHCC) with tensile Strain-Hardening were the developed composites. Both composites were applied on the tensile surface of masonry beams and the effectiveness of this technique for the flexural strengthening of these quasi-brittle structural elements was assessed by performing four point beam bending tests. Both materials contributed effectively to increase the load carrying capacity and ultimate deflection ductility of the tested masonry beams, but, higher average values were obtained for these two indicators of the strengthening effectiveness when using a layer thickness of SHCC that is 2/3 of the thickness of SFRSCC. Furthermore, much more homogenous results, in terms of forcedeflection relationship, were obtained with masonry beams strengthened with SHCC than with SFRSCC

    NASA LeRC's Acoustic Fill Effect Test Program and Results

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    NASA Lewis Research Center, in conjunction with General Dynamics Space Systems Division, has performed a test program to investigate the acoustic fill effect for an unblanketed payload fairing for a variety of payload simulators. This paper will discuss this test program and fill factor test data, and make comparisons with theoretical predictions. This paper will also address the NASA acoustic fill effect standard which was verified from the test data analysis

    A Study of the Accuracy of Mass-Radius Relationships for Silicate-Rich and Ice-Rich Planets up to 100 Earth Masses

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    A mass-radius relationship is proposed for solid planets and solid cores ranging from 1 to 100 Earth-mass planets. It relies on the assumption that solid spheres are composed of iron and silicates, around which a variable amount of water is added. The M-R law has been set up assuming that the planetary composition is similar to the averaged composition for silicates and iron obtained from the major elements ratio of 94 stars hosting exoplanets. Except on Earth for which a tremendous amount of data is available, the composition of silicate mantles and metallic cores cannot be constrained. Similarly, thermal profiles are poorly known. In this work, the effect of compositional parameters and thermal profiles on radii estimates is quantified. It will be demonstrated that uncertainties related to composition and temperature are of second order compared to the effect of the water amount. The Super-Earths family includes four classes of planets: iron-rich, silicate-rich, water-rich, or with a thick atmosphere. For a given mass, the planetary radius increases significantly from the ironrich to the atmospheric-rich planet. Even if some overlaps are likely, M-R measurements could be accurate enough to ascertain the discovery of an earth-like planet .The present work describes how the amount of water can be assessed from M-R measurements. Such an estimate depends on several assumptions including i) the accuracy of the internal structure model and ii) the accuracy of mass and radius measurements. It is shown that if the mass and the radius are perfectly known, the standard deviation on the amount of water is about 4.5 %. This value increases rapidly with the radius uncertainty but does not strongly depend on the mass uncertainty.Comment: In press in The Astrophysical Journa

    Measuring Accuracy of Automated Parsing and Categorization Tools and Processes in Digital Investigations

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    This work presents a method for the measurement of the accuracy of evidential artifact extraction and categorization tasks in digital forensic investigations. Instead of focusing on the measurement of accuracy and errors in the functions of digital forensic tools, this work proposes the application of information retrieval measurement techniques that allow the incorporation of errors introduced by tools and analysis processes. This method uses a `gold standard' that is the collection of evidential objects determined by a digital investigator from suspect data with an unknown ground truth. This work proposes that the accuracy of tools and investigation processes can be evaluated compared to the derived gold standard using common precision and recall values. Two example case studies are presented showing the measurement of the accuracy of automated analysis tools as compared to an in-depth analysis by an expert. It is shown that such measurement can allow investigators to determine changes in accuracy of their processes over time, and determine if such a change is caused by their tools or knowledge.Comment: 17 pages, 2 appendices, 1 figure, 5th International Conference on Digital Forensics and Cyber Crime; Digital Forensics and Cyber Crime, pp. 147-169, 201

    A SQUAMOSA MADS-box gene involved in the regulation of anthocyanin accumulation in bilberry fruits

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    Anthocyanins are important health promoting phytochemicals that are abundant in many fleshy fruits. Bilberry (Vaccinium myrtillus L.) is one of the best sources of these compounds. Here we report on the expression pattern and functional analysis of a SQUAMOSA (SQUA) class MADS-box transcription factor, VmTDR4, associated with anthocyanin biosynthesis in bilberry. Levels of VmTDR4 expression were spatially and temporally linked with colour development and anthocyanin-related gene expression. Virus induced gene silencing (VIGS) was used to suppress VmTDR4 expression in bilberry resulting in substantial reduction in anthocyanin levels in fully ripe fruits. Chalcone synthase was used a positive control in the VIGS experiments. Additionally, in sectors of fruit tissue in which the expression of the VmTDR4 gene was silenced, the expression of R2R3 MYB family transcription factors related to the biosynthesis of flavonoids were also altered. We conclude that VmTDR4 plays an important role in the accumulation of anthocyanins during normal ripening in bilberry; probably through direct or indirect control of transcription factors belonging to the R2R3 MYB family
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