Electrical Conductivity and Gamma Ray Response to Clay, Water, and Chloride Content in Fissured Sediments, Trans-Pecos, Texas

Near-surface conductivity profiles determined using surface and borehole electromagnetic induction instruments were compared with each other and with variations in several important hydrological parameters, including clay content, water content, and chloride content in unsaturated sediments in fissured settings. Time-domain electromagnetic soundings were acquired at 10 boreholes in the Eagle Flat, Red Light Bolson, Hueco Bolson, and Ryan Flat areas in the arid Trans-Pecos region of West Texas. These boreholes were logged with induction and passive radiation probes to determine conductivity profiles and natural gamma ray activity. At the Red Light Bolson and Hueco Bolson fissures, the gamma logs were sensitive to clay content and followed the conventional trend of increasing count rates with increasing clay content. At Eagle Flat, gamma count rates were not much higher in the clay fraction than they were in the silt and sand fraction; thus, the gamma log underestimated the variability in clay content. At the Ryan Flat fissure, gamma count rates were higher than for the other fissure sites and were higher for the sand and silt fraction than for the clay fraction. This suggests that the sedimentary grains making up these deposits are volcanogenic and that the coarse fraction contains a larger percentage of K-bearing minerals than the clay fraction.Bureau of Economic Geolog

Strong mass effect on ion beam mixing in metal bilayers

Molecular dynamics simulations have been used to study the mechanism of ion beam mixing in metal bilayers. We are able to explain the ion induced low-temperature phase stability and melting behavior of bilayers using only a simple ballistic picture up to 10 keV ion energies. The atomic mass ratio of the overlayer and the substrate constituents seems to be a key quantity in understanding atomic mixing. The critical bilayer mass ratio of $\delta < 0.33$ is required for the occurrence of a thermal spike (local melting) with a lifetime of $\tau > 0.3$ ps at low-energy ion irradiation (1 keV) due to a ballistic mechanism. The existing experimental data follow the same trend as the simulated values.Comment: 4 pages, 4 figures, preprin

Special issue: Innovations in farming systems approaches: Introduction

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Potential sinks for geologic storage of carbon dioxide generated by power plants in North and South Carolina

Duke Energy Progress Energy Santee Cooper Power SCANA CorporationBureau of Economic Geolog

First Measurements with NeXtRAD, a Polarimetric X/L Band Radar Network

NeXtRAD is a fully polarimetric, X/L Band radar network. It is a development of the older NetRAD system and builds on the experience gained with extensive deployments of NetRAD for sea clutter and target measurements. In this paper we will report on the first measurements with NeXtRAD, looking primarily at sea clutter and some targets, as well as early attempts at calibration using corner reflectors, and an assessment of the polarimetric response of the system. We also highlight innovations allowing for efficient data manipulation post measurement campaigns, as well as the plans for the coming years with this system

Pharmacology of DB844, an orally active aza analogue of pafuramidine, in a monkey model of second stage human African trypanosomiasis

Novel drugs to treat human African trypanosomiasis (HAT) are still urgently needed despite the recent addition of nifurtimox-eflornithine combination therapy (NECT) to WHO Model Lists of Essential Medicines against second stage HAT, where parasites have invaded the central nervous system (CNS). The pharmacology of a potential orally available lead compound, N-methoxy-6-{5-[4-(N-methoxyamidino) phenyl]-furan-2-yl}-nicotinamidine (DB844), was evaluated in a vervet monkey model of second stage HAT, following promising results in mice. DB844 was administered orally to vervet monkeys, beginning 28 days post infection (DPI) with Trypanosoma brucei rhodesiense KETRI 2537. DB844 was absorbed and converted to the active metabolite 6-[5-(4-phenylamidinophenyl)-furanyl-2-yl]-nicotinamide (DB820), exhibiting plasma C(max) values of 430 and 190 nM for DB844 and DB820, respectively, after the 14th dose at 6 mg/kg qd. A 100-fold reduction in blood trypanosome counts was observed within 24 h of the third dose and, at the end of treatment evaluation performed four days post the last drug dose, trypanosomes were not detected in the blood or cerebrospinal fluid of any monkey. However, some animals relapsed during the 300 days of post treatment monitoring, resulting in a cure rate of 3/8 (37.5%) and 3/7 (42.9%) for the 5 mg/kg×10 days and the 6 mg/kg×14 days dose regimens respectively. These DB844 efficacy data were an improvement compared with pentamidine and pafuramidine both of which were previously shown to be non-curative in this model of CNS stage HAT. These data show that synthesis of novel diamidines with improved activity against CNS-stage HAT was possible