Characterization of Piedmont Residual Soil and Saprolite in Maryland

Residual soils in the Eastern Piedmont Physiographic province are difficult to characterize because of the unique mineralogy and development of the soils. They are derived in place by weathering of the underlying gneiss and schist bedrock, and are characterized by a gradual transition from soil to decomposed-rock to rock with no clear demarcation between the strata. The soils generally consist of low plasticity micaceous clayey silts, sandy silts and silty sands. It is often difficult to obtain undisturbed samples of these soils and Intermediate Geo-Materials, so most shear strength and compressibility properties are derived from experience or correlations with index parameters such as the SPT N-value and Atterberg limits. For the State of Maryland’s Intercounty Connector (ICC) Project, the General Engineering Consultant (GEC), Intercounty Connector Corridor Partners (ICCCP) Joint Venture working directly for the Maryland State Highway Administration (MSHA), performed a Preliminary Geotechnical Subsurface Exploration (PGSE) during the procurement phase so that the Design-Build (DB) teams would develop preliminary designs on which to base their technical and price proposals. As part of the PGSE performed by the GEC for Contract A of the ICC, several undisturbed samples were obtained so that the shear strength parameters could be determined on relatively undisturbed samples. An attempt was made to correlate the SPT N-values and laboratory testing with seismic refraction geophysical exploration to estimate engineering parameters for design of cut slopes, shrink/swell, a cut/cover tunnel, and several bridges for the three general strata. Not only were undisturbed samples tested to determine the shear strength parameters, remolded samples, compacted to 95% of the modified Proctor maximum dry density, were also tested to determine the remolded shear strength parameters for embankment construction

Tied-Back Top-Down Wall to Support I-295 Ramp

Woodrow Wilson Replacement Bridge Project included widening the Washington Beltway (I-95/I-495) Outer Loop from three lanes to six-lanes. This required supporting two existing ramps that connect I-295 and MD 210 as well as the existing Mechanically Stabilized Earth (MSE) wall that supports the ramps. The MSE is about 17-ft tall, about 570-ft long, and at the top of a slope. A tied-back soldier pile and lagging wall with cast-in-place facing was selected to support the MSE and the ramps. The new wall will be about 1,376-ft long and will be as high as 37-ft. The closest approach of the wall to the existing MSE is about 3-ft. Laboratory testing was supplemented with Dilatometer Test (DMT) and Cone Penetration Test (CPT) soundings. PYWall and PLAXIS were used to estimate wall deflections and bending moments in the soldier piles. This paper reviews the analysis techniques, describes the design and the construction methods, and the instrumentation used to monitor the wall and MSE movements. The results of the computer simulations were compared to the inclinometer results. As work progressed simulations were updated by modifying the soil parameters to obtain calculated results that are more nearly consistent with the instrumentation readings

The Role of the Magnetic Field in the Interstellar Medium of the Post-Starburst Dwarf Irregular Galaxy NGC 1569

(abridged) NGC 1569 is a nearby dwarf irregular galaxy which underwent an intense burst of star formation 10 to 40 Myr ago. We present observations that reach surface brightnesses two to eighty times fainter than previous radio continuum observations and the first radio continuum polarization observations. These observations allow us to probe the relationship of the magnetic field of NGC 1569 to the rest of its interstellar medium. We confirm the presence of an extended radio continuum halo at 20 cm and see for the first time the radio continuum feature associated with the western Halpha arm at wavelengths shorter than 20cm. The spectral index trends in this galaxy support the theory that there is a convective wind at work in this galaxy. We derive a total magnetic field strength of 38 microG in the central regions and 10-15 microG in the halo. The magnetic field is largely random in the center of the galaxy; the uniform field is ~3-9 microG and is strongest in the halo. We find that the magnetic pressure is the same order of magnitude but, in general, a factor of a few less than the other components of the interstellar medium in this galaxy. The uniform magnetic field in NGC 1569 is closely associated with the Halpha bubbles and filaments. We suggest that a supernova-driven dynamo may be operating in this galaxy. The outflow of hot gas from NGC 1569 is clearly shaping the magnetic field, but the magnetic field in turn may be aiding the outflow by channeling gas out of the disk of the galaxy. Dwarf galaxies with extended radio continuum halos like that of NGC 1569 may play an important role in magnetizing the intergalactic medium.Comment: ApJ accepted. 56 pages, 14 figures (low resolution), 8 tables. Version with high resolution figures at http://www.astro.virginia.edu/~aak8t/data/n1569/ms.pd

Target gene selectivity of the myogenic basic helix–loop–helix transcription factor myogenin in embryonic muscle

AbstractThe myogenic regulatory factors MyoD and myogenin are crucial for skeletal muscle development. Despite their importance, the mechanisms by which these factors selectively regulate different target genes are unclear. The purpose of the present investigation was to compare embryonic skeletal muscle from myogenin+/+ and myogenin−/− mice to identify genes whose expression was dependent on the presence of myogenin but not MyoD and to determine whether myogenin-binding sites could be found within regulatory regions of myogenin-dependent genes independent of MyoD. We identified a set of 140 muscle-expressed genes whose expression in embryonic tongue muscle of myogenin−/− mice was downregulated in the absence of myogenin, but in the presence of MyoD. Myogenin bound within conserved regulatory regions of several of the downregulated genes, but MyoD bound only to a subset of these same regions, suggesting that many downregulated genes were selective targets of myogenin. The regulatory regions activated gene expression in cultured myoblasts and fibroblasts overexpressing myogenin or MyoD, indicating that expression from exogenously introduced DNA could not recapitulate the selectivity for myogenin observed in vivo. The results identify new target genes for myogenin and show that myogenin's target gene selectivity is not based solely on binding site sequences

Strongly correlated quantum dots in weak confinement potentials and magnetic fields

We explore a strongly correlated quantum dot in the presence of a weak confinement potential and a weak magnetic field. Our exact diagonalization studies show that the groundstate property of such a quantum dot is rather sensitive to the magnetic field and the strength of the confinement potential. We have determined rich phase diagrams of these quantum dots. Some experimental consequences of the obtained phase diagrams are discussed.Comment: 5 pages, 7 figures, new and updated figure

Dying To Find Out: The Cost of Time at the Dawn of the Multicancer Early Detection Era

Cancer is a significant burden worldwide that adversely impacts life expectancy, quality of life, health care costs, and workforce productivity. Although currently recommended screening tests for individual cancers reduce mortality, they detect only a minority of all cancers and sacrifice specificity for high sensitivity, resulting in a high cumulative rate of false positives. Blood-based multicancer early detection tests (MCED) based on next-generation sequencing (NGS) and other technologies hold promise for broadening the number of cancer types detected in screened populations and hope for reducing cancer mortality. The promise of this new technology to improve cancer detection rates and make screening more efficient at the population level demands the development of novel trial designs that accelerate clinical adoption. Carefully designed clinical trials are needed to address these issues

Real-time motion analytics during brain MRI improve data quality and reduce costs

Head motion systematically distorts clinical and research MRI data. Motion artifacts have biased findings from many structural and functional brain MRI studies. An effective way to remove motion artifacts is to exclude MRI data frames affected by head motion. However, such post-hoc frame censoring can lead to data loss rates of 50% or more in our pediatric patient cohorts. Hence, many scanner operators collect additional 'buffer data', an expensive practice that, by itself, does not guarantee sufficient high-quality MRI data for a given participant. Therefore, we developed an easy-to-setup, easy-to-use Framewise Integrated Real-time MRI Monitoring (FIRMM) software suite that provides scanner operators with head motion analytics in real-time, allowing them to scan each subject until the desired amount of low-movement data has been collected. Our analyses show that using FIRMM to identify the ideal scan time for each person can reduce total brain MRI scan times and associated costs by 50% or more