Laboratory Characterization and Influence of Mineralogy and Grading on the Performance of Treated and Untreated Granular Materials Used as Surface Pavements in Unpaved Road

This paper presents the results of a laboratory study on the influence of grading and granular mineralogy sources (granitic gneiss, basalt and limestone) on the performance of treated and untreated granular materials used as surface pavements in unpaved roads. Results of bearing capacity, resilient modulus and compressive strength tests are discussed. Natural brine, calcium chloride, cement and a polymer emulsion treated samples were tested and compared to untreated samples. The combinations of product, mineralogy and grading showing great performance are finally pointed out

Retention of Science Majors Through Different Avenues of General Chemistry Education

For the past two academic years, the chemistry division at Longwood University has implemented POGIL methodology in some sections of the general chemistry sequence for science majors. Initially we were interested in determining if students exposed to POGIL were more successful in general chemistry than those students that were not exposed to this teaching pedagogy. Subsequent studies compare conceptual learning outcomes of POGIL versus non-POGIL students and also try to determine if SAT and GALT scores are a good predictors of student success in general chemistry. This project also addresses the following question:do science majors exposed to POGIL pedagogy in first semester general chemistry demonstrate increased success in subsequent chemistry courses compared to those students with no POGIL experience? Details about POGIL implementation and challenges as well as the methods of assessment used are discussed

Field and Laboratory Investigations on the Use of Fly Ash and LI-Based Admixtures to Prevent ASR in Concrete

Since the early 1990’s, CANMET (Department of Natural Resources Canada) is carrying out a comparative field and laboratory research program to investigate the efficacy of laboratory test procedures for properly predicting the long-term efficacy of supplementary cementitious materials (SCM) in controlling expansion due to alkali-silica reaction (ASR). Binary and ternary concrete systems, i.e. fly ash (Class F), lithium-based admixtures, fly ash / Li-based admixtures, were selected with a variety of alkali-silica reactive aggregates. The expansive behaviour of the various combinations listed above was investigated in the laboratory using concrete prisms stored under accelerated test conditions (38oC and 100% RH). Exposure blocks cast from the above mixtures were placed outdoors at the CANMET facilities located in Ottawa (Canada). This paper compares the results of expansion testing in the laboratory against that of exposure blocks after 15 years outdoors. The results are also analysed in view of providing recommendations for the use of such materials / combinations for the manufacture of concrete that will be at a minimum risk of developing deleterious expansion and cracking due to ASR

RNA splicing at human immunodeficiency virus type 1 3 ' splice site A2 is regulated by binding of hnRNP A/B proteins to an exonic splicing silencer element

The synthesis of human immunodeficiency virus type 1 (HIV-1) mRNAs is a complex process by which more than 30 different mRNA species are produced by alternative splicing of a single primary RNA transcript. HIV-1 splice sites are used with significantly different efficiencies, resulting in different levels of mRNA species in infected cells. Splicing of Tat mRNA, which is present at relatively low levels in infected cells, is repressed by the presence of exonic splicing silencers (ESS) within the two tat coding exons (ESS2 and ESS3). These ESS elements contain the consensus sequence PyUAG. Here we show that the efficiency of splicing at 3 ' splice site A2, which is used to generate Vpr mRNA, is also regulated by the presence of an ESS (ESSV), which has sequence homology to ESS2 and ESS3. Mutagenesis of the three PyUAG motifs within ESSV increases splicing at splice site A2, resulting in increased Vpr mRNA levels and reduced skipping of the noncoding exon flanked by A2 and D3. The increase in Vpr mRNA levels and the reduced skipping also occur when splice site D3 is mutated toward the consensus sequence. By in vitro splicing assays, we show that ESSV represses splicing when placed downstream of a heterologous splice site. A1, A1(B), A2, and B1 hnRNPs preferentially bind to ESSV RNA compared to ESSV mutant RNA. Each of these proteins, when added back to HeLa cell nuclear extracts depleted of ESSV-binding factors, is able to restore splicing repression. The results suggest that coordinate repression of HIV-1 RNA splicing is mediated by members of the hnRNP A/B protein family

Early quantitative coronary angiography of saphenous vein grafts for coronary artery bypass grafting harvested by means of open versus endoscopic saphenectomy: a prospective randomized trial

AbstractObjectiveEndoscopic saphenectomy is associated with a decreased incidence of wound complications without an increase in histologic trauma or endothelial dysfunction in published reports. Concern remains about the patency of saphenous vein grafts harvested endoscopically and the development of early intimal hyperplasia. The purpose of this study was to compare early quantitative coronary analysis of saphenous vein grafts used for coronary artery bypass grafting harvested with the open versus endoscopic techniques.MethodsForty patients undergoing primary coronary artery bypass grafting surgery with at least 1 saphenous vein graft were randomized preoperatively to open versus endoscopic saphenectomy with bipolar cauterization of side branches. Quantitative coronary angiography was performed a mean of 3 months (range, 1-9 months) after the operation.ResultsThere was no statistically significant difference in the patency rates of internal thoracic artery grafts between the open and endoscopic groups and no statistically significant difference in the patency rates of saphenous vein grafts between both groups (85.2% vs 84.4%, P = .991). Quantitative coronary angiography showed no difference in graft stenosis (≥50% of the internal diameter of the graft) in the body of the saphenous vein grafts in the open versus endoscopic saphenectomy groups (3.7% vs 0%, P = .280).ConclusionAngiographic appearance and patency rates of saphenous vein grafts harvested with the endoscopic technique are similar to those of saphenous vein grafts harvested with the open technique. These results support the use of endoscopic saphenectomy because of the known lower incidence of wound and infectious complications and superior functional results

Automated CO2 and CH4 monitoring system for continuous estimation of degassing related to hydropower

Reliable measurement of greenhouse gas emissions from reservoirs is essential for estimating the carbon footprint of the hydropower industry. Among the different emission pathways, degassing downstream of the turbines and spillway is poorly documented mainly because of the safety stakes related to sampling up and downstream the power plants. The alternative being to sample the water from the turbine inside the station, this study aimed to assemble a custom automated CO2 and CH4 monitoring system (SAGES), especially designed for long-term surveys in hydropower facilities, with a special focus on low maintenance requirements. The SAGES combines infrared and laser technologies with a modular programming approach and run with a specifically designed plexiglass equilibration system (PES) that maintain a permanent headspace and avoid clogging by suspended solids. Although the SAGES is based on commercially available devices, it is the first time they are combined and used with the gas equilibrator. To ensure the reliability of the mounting and to control the quality of the readings, the system was tested in laboratory prior to its installation in generating stations. SAGES and PES performances were compared with those of generic devices available on the market although less adapted to the specific deployments targeted. The SAGES gas partial pressure measurements were accurate and linear in the entire range tested: 0 to 5,000 ppm for pCO2 and 0 to 600 and 10,000 ppm for pCH4. Gas PP measurements were comparable to the reference CO2/CH4 sensor and there was no drift during long term deployment. The SAGES/PES installed in 2021 in cascading generating stations of the Romaine complex collected more than 28,000 data points over a 10-month period and required only two maintenances. Results show that the SAGES is a reliable tool that provide long-term CO2 and CH4 dataset in generating stations while requiring minimal energy, care and maintenance. The data collected in turbine water and the recent use of the SAGES in peat land by a collaborative team demonstrate how the SAGES systems can efficiently contribute to the understanding of reservoir carbon cycles

Probabilistic Clustering of Time-Evolving Distance Data

We present a novel probabilistic clustering model for objects that are represented via pairwise distances and observed at different time points. The proposed method utilizes the information given by adjacent time points to find the underlying cluster structure and obtain a smooth cluster evolution. This approach allows the number of objects and clusters to differ at every time point, and no identification on the identities of the objects is needed. Further, the model does not require the number of clusters being specified in advance -- they are instead determined automatically using a Dirichlet process prior. We validate our model on synthetic data showing that the proposed method is more accurate than state-of-the-art clustering methods. Finally, we use our dynamic clustering model to analyze and illustrate the evolution of brain cancer patients over time

K600 Small Angle Operation

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

K600 Small Angle Development

This research was sponsored by the National Science Foundation Grant NSF PHY-931478