The authors present the results from an analysis of Hubble Space Telescope High Resolution Camera data for the Large Magellanic Cloud microlensing event MACHO-LMC-5. By determining the parallax and proper motion of this object they find that the lens is an M dwarf star at a distance of 578{sub -53}{sup +65}pc with a proper motion of 21.39 {+-} 0.04 mas/yr. Based on the kinematics and location of this star is it more likely to be part of the Galactic thick disk than thin disk population. They confirm that the microlensing event LMC-5 is a jerk-parallax microlensing event.

The technique of accelerator mass spectrometry (AMS) was validated successfully and utilized to study the pharmacokinetics and disposition in dogs of a preclinical drug candidate (Compound A), after oral and intravenous administration. The primary objective of this study was to examine whether Compound A displayed linear kinetics across sub-pharmacological (microdose) and pharmacological dose ranges in an animal model, prior to initiation of a human microdose study. The AMS-derived disposition properties of Compound A were comparable to data obtained via conventional techniques such as LC-MS/MS and liquid scintillation counting analyses. Thus, Compound A displayed multiphasic kinetics and possessed low plasma clearance (4.4 mL/min/kg), a long terminal elimination half-life (19.4 hr) and high oral bioavailability (82%). Currently there are no published comparisons of the kinetics of a pharmaceutical compound at pharmacological versus sub-pharmacological doses employing microdosing strategies. The present study thus provides the first description of the pharmacokinetics of a drug candidate assessed under these two dosing regimens. The data demonstrated that the pharmacokinetic properties of Compound A were similar following dosing at 0.02 mg/kg as at 1 mg/kg, indicating that in the case of Compound A, the kinetics of absorption, distribution and elimination in the dog appear to be linear across …

The current experimental lower bound on the Higgs mass significantly restricts the allowed parameter space in most realistic supersymmetric models, with the consequence that these models exhibit significant fine-tuning. We propose a solution to this `supersymmetric little hierarchy problem'. We consider scenarios where the stop masses are relatively heavy - in the 500 GeV to a TeV range. Radiative stability of the Higgs soft mass against quantum corrections from the top quark Yukawa coupling is achieved by imposing a global SU(3) symmetry on this interaction. This global symmetry is only approximate - it is not respected by the gauge interactions. A subgroup of the global symmetry is gauged by the familiar SU(2) of the Standard Model. The physical Higgs is significantly lighter than the other scalars because it is the pseudo-Goldstone boson associated with the breaking of this symmetry. Radiative corrections to the Higgs potential naturally lead to the right pattern of gauge and global symmetry breaking. We show that both the gauge and global symmetries can be embedded into a single SU(6) grand unifying group, thereby maintaining the prediction of gauge coupling unification. Among the firm predictions of this class of models are new states with the quantum numbers …

The conceptual design and preliminary engineering calculations have been completed for a two cassette cryostat. This report summarizes the design. A cryocooler is permanently mounted in the center of a stainless steel, 0.75 inch thick top lid. The cryocooler sits upon a spacer which raises the cooling stage elevations to favorably match the cassette heat intercept elevations. The top lid (32.0-inch outside diameter) mates to a 24-inch pipe size flange with o-ring. The 24-inch pipe size vacuum vessel with end plate has a minimum internal depth of 16-inch to give adequate clearance for the depth of the cryocooler and multilayer insulation blankets. Support stand legs elevate the container to a convenient height and allow for placement of the AFE power supply underneath. Two cassette slots are located on either side of the cryocooler. The slots are positioned parallel to each other, 10.5-inch center to center (6 standard cassette slot widths) so that the standard 8 slot AFE backplane can be used. The slot opening through the lid is approximately 1.422-inch x 16.782-inch. A 0.016-inch thick titanium (Ti-6AI-4V) envelope with sealing lip is inserted through lid and defines the gas helium boundary that the VLPC cassette resides. The internal dimensions of …

Since the late 1950s, leaks from 67 single-shell tanks at the Hanford Site have released about 1 million curies to the underlying sediments. The radioactive material was contained in water-based solutions generally characterized as having high pH values (basic solutions), high nitrate and nitrite concentrations, and high aluminum concentrations. The solutions were also hot, in some cases at or near boiling, as well as complex and highly variable in composition reflecting solutions obtained from multiple methods of reprocessing spent nuclear fuel. In order to understand the observed and probable distribution of radionuclides in the ground at Hanford, major reactions that likely occurred between the leaked fluids and the sediment minerals were investigated in laboratory experiments simulating environmental conditions. Reactions involving the dissolution of quartz and biotite and the simultaneous formation of new minerals were quantified at controlled pH values and temperature. Result s show that the dissolution of quartz and formation of new zeolite-like minerals could have altered the flow path of ground water and contaminant plumes and provided an uptake mechanism for positively-charged soluble radionuclides, such as cesium. The dissolution of biotite, a layered-iron-aluminum-silicate mineral, provided iron in a reduced form that could have reacted with negatively-charged soluble chromium, …

Recovery and comparison of toolmarks, footprint impressions, and fractured surfaces connected to a crime scene are of great importance in forensic science. The purpose of this project is to provide statistical tools for the validation of the proposition that particular manufacturing processes produce marks on the work-product (or tool) that are substantially different from tool to tool. The approach to validation involves the collection of digital images of toolmarks produced by various tool manufacturing methods on produced work-products and the development of statistical methods for data reduction and analysis of the images. The developed statistical methods provide a means to objectively calculate a ''degree of association'' between matches of similarly produced toolmarks. The basis for statistical method development relies on ''discriminating criteria'' that examiners use to identify features and spatial relationships in their analysis of forensic samples. The developed data reduction algorithms utilize the same rules used by examiners for classification and association of toolmarks.

Significant differences (approximately 30 percent) have been observed in the sulfur measurements in high-level waste sludge by the Analytical Development Section (ADS) using the inductively coupled plasma-atomic emission spectroscopy (ICP-AES) method compared with the ADS ion chromatography (IC) method. Since the measured concentrations of sulfur in the sludge approached the maximum concentration that can be processed in the DWPF, experiments were performed to determine the source of the differences and assess the true accuracy of sulfur measurements.

Bioenergy crops, which displace fossil fuels when used to produce ethanol, biobased products, and/or electricity, have the potential to further reduce atmospheric carbon levels by building up soil carbon levels, especially when planted on lands where these levels have been reduced by intensive tillage. The purpose of this study is to improve the characterization of the soil carbon (C) sequestration for bioenergy crops (switchgrass, poplars, and willows) in the Greenhouse gases, Regulated Emissions, and Energy Use in Transportation (GREET) model (Wang 1999) by using the latest results reported in the literature and by Oak Ridge National Laboratory (ORNL). Because soil carbon sequestration for bioenergy crops can play a significant role in reducing greenhouse gas (GHG) emissions for cellulosic ethanol, it is important to periodically update the estimates of soil carbon sequestration from bioenergy crops as new and better data become available. We used the three-step process described below to conduct our study.

Research has shown that Active Pixel CMOS sensors can detect charged particles. We have been studying whether this process can be used in a collider environment. In particular, we studied the effect of radiation with 55 MeV protons. These results show that a fluence of about 2 x 10{sup 12} protons/cm{sup 2} reduces the signal by a factor of two while the noise increases by 25%. A measurement 6 months after exposure shows that the silicon lattice naturally repairs itself. Heating the silicon to 100 C reduced the shot noise and increased the collected charge. CMOS sensors have a reduced signal to noise ratio per pixel because charge diffuses to neighboring pixels. We have constructed a photogate to see if this structure can collect more charge per pixel. Results show that a photogate does collect charge in fewer pixels, but it takes about 15 ms to collect all of the electrons produced by a pulse of light.

A dosage analysis of gene expression was conducted using aneuploids of maize. The findings of this project led to the concept that regulatory genes in higher eukaryotes has mostly dosage dependent and are the underlying basis of quantitative traits and aneuploid syndromes.

The growth of nanocrystalline MoO{sub 3} islands on Au(111) using physical vapor deposition of Mo has been studied by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). The growth conditions affect the shape and distribution of the MoO{sub 3} nanostructures, providing a means of preparing materials with different percentages of edge sites that may have different chemical and physical properties than atoms in the interior of the nanostructures. MoO{sub 3} islands were prepared by physical vapor deposition of Mo and subsequent oxidation by NO{sub 2}exposure at temperatures between 450 K and 600 K. They exhibit a crystalline structure with a c(4x2) periodicity relative to unreconstructed Au(111). While the atomic-scale structure is identical to that of MoO{sub 3} islands prepared by chemical vapor deposition, we demonstrate that the distribution of MoO{sub 3} islands on the Au(111) surface reflects the distribution of Mo clusters prior to oxidation although the growth of MoO{sub 3} involves long-range mass transport via volatile MoO{sub 3} precursor species. The island morphology is kinetically controlled at 450 K, whereas an equilibrium shape is approached at higher preparation temperatures or after prolonged annealing at the elevated temperature. Mo deposition at or above 525 K leads to the …

A stress corrosion cracking (SCC) model has been adapted for performance prediction of high level radioactive-waste packages to be emplaced in the proposed Yucca Mountain radioactive-waste repository. SCC is one form of environmentally assisted cracking resulting from the presence of three factors: metallurgical susceptibility, critical environment, and tensile stresses. For waste packages of the proposed Yucca Mountain repository, the outer barrier material is the highly corrosion-resistant Alloy UNS-N06022, the environment is represented by the water film present on the surface of the waste package from dripping or deliquescence of soluble salts present in any surface deposits, and the stress is principally the weld induced residual stress. SCC has historically been separated into 'initiation' and 'propagation' phases. Initiation of SCC will not occur on a smooth surface if the surface stress is below a threshold value defined as the threshold stress. Cracks can also initiate at and propagate from flaws (or defects) resulting from manufacturing processes (such as welding). To account for crack propagation, the slip dissolution/film rupture (SDFR) model is adopted to provide mathematical formulae for prediction of the crack growth rate. Once the crack growth rate at an initiated SCC is determined, it can be used by the performance …

The objective of this project was to define the mechanisms, equilibria, kinetics, and extent of sorption of aqueous uranium onto hydroxyapatite (Ca{sub 5}(PO{sub 4}){sub 3}(OH)) for a range of pH, ionic strength, aqueous uranium concentration, dissolved carbon/air CO{sub 2}, and mineral surface area. We conducted chemical modeling, batch and flow-through experiments, chemical analysis, x-ray absorption and diffraction measurement, and electron microscopy. Our motivation was the need to immobilize U in water and soil to prevent it's entry into water supplies and ultimately, biological systems. Applying hydroxyapatite to in-situ treatment of uranium-bearing ground water could be an effective, low cost technology. We found that hydroxyapatite quickly, effectively, and reversibly sorbed uranium at a high capacity by inner-sphere complexation over a wide range of conditions. Our results indicate that at aqueous uranium concentrations below 10-20 ppb: (1) equilibrium sorption of uranium to hydroxyapatite occurs in hours, regardless of pH; (2) in ambient and CO{sub 2}-free atmospheres, over 98% of initial uranium is sorbed to hydroxyapatite, (3) in waters in equilibrium with higher air CO{sub 2} concentrations, sorption removed over 97% of aqueous uranium, except above pH 9, where aqueous uranium concentrations were reduced by less than 40%, and (4) at near-neutral pH, …

Optimized trajectories to a 500 km circular orbit are calculated for vehicles having a 100 kg Mars launch mass. Staging trades, thrust optimization, and the importance of vehicle shape for drag are all taken into consideration. The high acceleration of solid rockets requires a steep trajectory for drag avoidance, followed by a relatively large circularization burn, appropriate for a second stage. Liquid thrust reduces drag, resulting in less steep trajectories which have small circularization burns. Liquid propulsion requires less total {Delta}v, and offers options for multiple stages or just one. Graphs of payload mass versus stage propellant fractions are compared for liquid and solid propulsion.

Effective and reliable nuclear monitoring requires discrimination between small magnitude explosions and earthquakes based on the use of limited regional data. Lg is generally the largest seismic phase from both explosion and earthquake sources recorded at regional distances. For small events, Lg may sometimes be the only well-recorded seismic phase so that discriminants based only on the use of Lg are especially desirable. Recent research has provided significantly better understanding of Lg by demonstrating that the explosion-generated Rg makes significant contribution to the low-frequency S or Lg from explosions. Near-source scattering of explosion-generated Rg appears to be a viable mechanism for generating low-frequency(< 2 Hz) Lg waves from explosions. Detailed knowledge of the complex scattering process is, however, still incomplete and is in fact the subject of several ongoing studies. Our analysis of regional data from nuclear explosions from both Nevada Test Site (NTS) and Kazakh Test Site (KTS) and nearby earthquakes in Phase I has suggested that there are several reliable source discrimination methods only based on the use of Lg at regional distances. These discriminants should be. especially useful for small magnitude seismic events for which Lg may be the only well-recorded seismic phase. Our results suggest four …

This work has followed two themes: (1) Developing and using the adjoint of the MIT ocean biogeochemistry model to examine the efficiency of carbon sequestration in a global configuration. We have demonstrated the power of the adjoint method for systematic ocean model sensitivity studies. We have shown that the relative efficiency of carbon sequestration in the Atlantic and Pacific basins changes with the period of interest. For decadal to centennial scales, the Pacific is more efficient. On longer timescales the Atlantic is more efficient . (2) We have developed and applied a high-resolution, North Atlantic circulation and tracer model to investigate the role of the mesoscale in controlling sequestration efficiency. We show that the mesoscale eddy field, and its explicit representation, significantly affects the estimated sequestration efficiency for local sources on the Eastern US seaboard.

We use data from a unique 40-year record of 150 urban and rural stations in the ''Black Smoke and SO2 Network'' in Great Britain to infer information about sources of atmospheric black carbon (BC). The data show a rapid decline of ambient atmospheric BC between 1962 and the early 1990s that exceeds the decline in official estimates of BC emissions based only on amount of fuel use and mostly fixed emission factors. This provides empirical confirmation of the existence and large impact of a time-dependent ''technology factor'' that must multiply the rate of fossil fuel use. Current ambient BC amounts in Great Britain comparable to those in western and central Europe, with diesel engines being the principal present source. From comparison of BC and SO2 data we infer that current BC emission inventories understate true emissions in the U.K. by about a factor of two. The results imply that there is the potential for improved technology to achieve large reduction of global ambient BC. There is a need for comparable monitoring of BC in other countries.