1,156 research outputs found

    Investigation into improving PCC mix consistency and production rate by two-stage mixing

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    A two-stage mixing process for concrete involves mixing a slurry of the binder and water separate from the aggregates, and then adding the slurry to the aggregates and continuing mixing. This process could improve cement hydration, concrete homogeneity, and the interfacial transition zone (ITZ) between aggregate and paste. This study deals the first stage of the two-stage mixing process, slurry mixing. The objectives are to determine the optimum mixing time and intensity based on the paste binder properties tested and to make recommendations for further investigation of the second stage of the process. Two mixers were used for slurry mixing. A high shear and low shear mixer with varying mixing time and speed. Different binder combinations were tested utilizing cement, fly ash, and slag. Heat of hydration, maturity, and rheology tests were performed on fresh paste samples. Compressive strength, degree of hydration, and scanning electron microscope (SEM) imaging tests were completed on cured specimens. The results show that increasing the mixing energy (mixing speed and time) produces a more workable and uniform slurry. This conclusion is supported best by the degree of hydration and rheology tests of paste. After mixing energy reaches a certain level, rheological properties of a given paste may show little or no change with increasing mixing time. For a given mixing time, a high shear mixer generally provides paste with higher early-age strengths than a normal mixer. Based on the tests, an optimal mixer and mixing time are recommended for further research on the two-stage mixing process

    Fraudulent financial reporting: 1998-2007 : an analysis of U.S. public companies

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    https://egrove.olemiss.edu/aicpa_assoc/1534/thumbnail.jp

    How did large scale climate anomalies impact 2015 phytoplankton blooms in Puget Sound?

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    The Washington State Department of Ecology has been routinely monitoring marine water quality throughout the Puget Sound since 1973. An established historic baseline from 1999 to 2008 allows us to examine how water quality varies year to year as a result of both natural and human influences. The recent large scale climate anomaly, the Blob, impacted this region when a mass of warm water entered Puget Sound in fall 2014. In conjunction with higher than normal air temperatures, patterns of estuarine circulation and stratification were regionally altered in Puget Sound. Changes to these physical patterns affect ecosystem functions starting at the base of the food web with phytoplankton. The water quality data collected monthly in 2015 allows us to gain a better understanding of how large-scale climate anomalies affect the timing and amplitude of phytoplankton biomass (chlorophyll a) in different regions of Puget Sound. Exploring the regional changes in phytoplankton biomass in response to the Blob provides us with insight into how future climate impacts could effect ecosystem functioning in different regions of Puget Sound

    Asymptomatic sensitization to a cow\u27s milk protein induces sustained neuroinflammation and behavioral changes with chronic allergen exposure

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    Mouse models of food allergy have contributed to our understanding of various aspects of the disease, including susceptibilities, symptom spectra, cellular mechanisms, and therapeutic approaches. Previously, we used a mouse model of non-anaphylactic cow’s milk allergy (CMA) and investigated sex- and strain-dependent differences in immunological, neurological, and behavioral sequelae. We showed that male C57BL/6J mice sensitized to a bovine whey protein, β-lactoglobulin (BLG; Bos d 5), exhibited anxiety- and depression-like behavior upon acute allergen challenge. Systemic levels of BLG-specific immunoglobulins, cytokines and chemokines were also elevated in the sensitized mice. Furthermore, neuroinflammation and intestinal dysbiosis were evident as the possible causes of the altered behavior. To assess whether frequent allergen exposure influences CMA-associated pathologies over an extended period in this subclinical model, we placed BLG-sensitized mice on a whey protein (WP)-containing or whey-free control (CTL) diet for 3 months. As expected, allergen-specific IgE was significantly elevated in the plasma after completing the 5-week sensitization phase. However, the IgE levels declined in both diet groups after 3 months. In contrast, allergen-specific IgG1 stayed elevated in sensitized mice with the CTL diet, and the WP diet to a lesser extent. Interestingly, BLG-sensitized mice on the WP diet exhibited anxiety-like behavior and a trend toward spatial memory decline compared to the sham or the sensitized mice on the CTL diet. Moreover, increased immunoreactivities for GFAP and Iba1 and elevated levels of CXCL13 and CCL12, the chemokines involved in central leukocyte recruitment and other neurological diseases, were also observed in the brain. We demonstrated that sensitization to the whey protein, particularly with continuous allergen exposure, resulted in persistent neuroinflammation and associated behavioral changes despite lowered allergen-specific immunoglobulin levels. These results suggested that continuous consumption of the offending allergen may lead to adverse consequences in the brain even after desensitizatio

    Fine structure of excitons in Cu2_2O

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    Three experimental observations on 1s-excitons in Cu2_2O are not consistent with the picture of the exciton as a simple hydrogenic bound state: the energies of the 1s-excitons deviate from the Rydberg formula, the total exciton mass exceeds the sum of the electron and hole effective masses, and the triplet-state excitons lie above the singlet. Incorporating the band structure of the material, we calculate the corrections to this simple picture arising from the fact that the exciton Bohr radius is comparable to the lattice constant. By means of a self-consistent variational calculation of the total exciton mass as well as the ground-state energy of the singlet and the triplet-state excitons, we find excellent agreement with experiment.Comment: Revised abstract; 10 pages, revtex, 3 figures available from G. Kavoulakis, Physics Department, University of Illinois, Urban

    Skilful seasonal predictions of Summer European rainfal

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    This is the author accepted manuscript. The final version is available from American Geophysical Union (AGU) via the DOI in this record.Year-to-year variability in Northern European summer rainfall has profound societal and economic impacts; however current seasonal forecast systems show no significant forecast skill. Here we show skilful predictions are possible (r~0.5, p80 members) are required for skilful predictions. This work is promising for the development of European summer rainfall climate services.This work was supported by the Joint DECC/Defra Met Office Hadley Centre Climate Programme (GA01101), the EU FP7 SPECS project. We acknowledge the E-OBS dataset from the EU-FP6 project ENSEMBLES (http://ensembles-eu.metoffice.com) and the data providers in the ECA&D project (http://www.ecad.eu). We also would like to thank Gerard van der Schrier and Else Van Den Besselaar for kindly providing us the pre-release E-OBS dataset version 'v16e' and further support. Model data used to create the figures are available from the authors upon request for academic use

    Temperature

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    KEY HEADLINES: • The first MCCIP ARC in 2006 reported following what was then the warmest year globally in 2005 (0.26°C higher than the 1981-2010 average). • Since 2005, new global record temperatures have been set in 2010 and then in each successive year 2014, 2015 and 2016. In these last three record years the global average temperature anomaly was 0.31,0.44, 0.56°C higher than the 1981-2010 average. • 2014 was a record warm year for coastal air and sea temperatures around the UK. Between 1984 and 2014 coastal water temperatures rose around the UK at an average rate of 0.28 °C/decade. The rate varies between regions, the slowest warming was in the Celtic Sea at 0.17 °C/decade and the maximum rate was in the Southern North Sea at 0.45 °C/decade. • There is also variability over shorter time periods. In all regions of UK seas there was a negative trend in the 10-year period between 2003 and 2013. This is due to variability within the ocean /atmosphere system which is natural. • There is a trend towards fewer in-situ observations, and this will ultimately influence the confidence in future assessments. • Some gridded datasets can offer alternatives to single point observations, but to understand the patterns of ocean variability, the quality information from ocean timeseries cannot yet be replaced by surface observations or autonomous data collection. • The first MCCIP report card in 2006 used the UKCIP projections from 2002 which had a very limited representation of the SST. • The latest updates to the UK Climate Projections shelf seas models were published in 2016 and projected increases in sea surface temperature for 2069-89 relative to 1960-89 of over 3 °C for most of the North Sea, English Channel, Irish and Celtic Seas. For the deeper areas to the north and west of Scotland out towards Rockall and in the Faroe Shetland Channel the increase in temperature is projected to be closer to 2 °C. • Over the last 10 years there has been a steady improvement in the scientific basis underlying centennial sea temperature projections for the seas around the UK, and significant progress in the field of seasonal and decadal projections. • The scientific basis to such projections and predictions will continue to improve over the next 10 years, with increasing resolution, treatment of climate uncertainties, and methodology. Over the centennial scale the difference between emissions scenarios are still the source of the largest uncertainties. • Development of North West European Shelf (NWS) modelling systems driven by seasonal forecasting systems may allow NWS temperature prediction over the monthly to decadal period

    Robust skill of decadal climate predictions

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    There is a growing need for skilful predictions of climate up to a decade ahead. Decadal climate predictions show high skill for surface temperature, but confidence in forecasts of precipitation and atmospheric circulation is much lower. Recent advances in seasonal and annual prediction show that the signal-to-noise ratio can be too small in climate models, requiring a very large ensemble to extract the predictable signal. Here, we reassess decadal prediction skill using a much larger ensemble than previously available, and reveal significant skill for precipitation over land and atmospheric circulation, in addition to surface temperature. We further propose a more powerful approach than used previously to evaluate the benefit of initialisation with observations, improving our understanding of the sources of skill. Our results show that decadal climate is more predictable than previously thought and will aid society to prepare for, and adapt to, ongoing climate variability and change.D.M.S., A.A.S., N.J.D., L.H. and R.E. were supported by the Met Office Hadley Centre Climate Programme funded by BEIS and Defra and by the European Commission Horizon 2020 EUCP project (GA 776613). L.P.C. was supported by the Spanish MINECO HIATUS (CGL2015-70353-R) project. F.J.D.R. was supported by the H2020 EUCP (GA 776613) and the Spanish MINECO CLINSA (CGL2017-85791-R) projects. W.A. M. and H.P. were supported by the German Ministry of Education and Research (BMBF) under the project MiKlip (grant 01LP1519A). The NCAR contribution was supported by the US National Oceanic and Atmospheric Administration (NOAA) Climate Program Office under Climate Variability and Predictability Program Grant NA13OAR4310138 and by the US National Science Foundation (NSF) Collaborative Research EaSM2 Grant OCE-1243015. The NCAR contribution is also based upon work supported by NCAR, which is a major facility sponsored by the US NSF under Cooperative Agreement No. 1852977. The Community Earth System Model Decadal Prediction Large Ensemble (CESM-DPLE) was generated using computational resources provided by the US National Energy Research Scientific Computing Center, which is supported by the Office of Science of the US Department of Energy under Contract DE-AC02-05CH11231, as well as by an Accelerated Scientific Discovery grant for Cheyenne (https://doi.org/10.5065/D6RX99HX) that was awarded by NCAR’s Computational and Information System Laboratory.Peer ReviewedPostprint (published version

    Epigenetic and Genetic Influences on DNA Methylation Variation in Maize Populations

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    DNA methylation is a chromatin modification that is frequently associated with epigenetic regulation in plants and mammals. However, genetic changes such as transposon insertions can also lead to changes in DNA methylation. Genome-wide profiles of DNA methylation for 20 maize (Zea mays) inbred lines were used to discover differentially methylated regions (DMRs). The methylation level for each of these DMRs was also assayed in 31 additional maize or teosinte genotypes, resulting in the discovery of 1966 common DMRs and 1754 rare DMRs. Analysis of recombinant inbred lines provides evidence that the majority of DMRs are heritable. A local association scan found that nearly half of the DMRs with common variation are significantly associated with single nucleotide polymorphisms found within or near the DMR. Many of the DMRs that are significantly associated with local genetic variation are found near transposable elements that may contribute to the variation in DNA methylation. Analysis of gene expression in the same samples used for DNA methylation profiling identified over 300 genes with expression patterns that are significantly associated with DNA methylation variation. Collectively, our results suggest that DNA methylation variation is influenced by genetic and epigenetic changes that are often stably inherited and can influence the expression of nearby genes
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