A letter report issued by the Government Accountability Office with an abstract that begins "Congress mandated in 2000 that the Centers for Medicare & Medicaid Services (CMS) conduct the Physician Group Practice (PGP) Demonstration to test a hybrid payment methodology for physician groups that combines Medicare fee-for-service payments with new incentive payments. The 10 participants, with 200 or more physicians each, may earn annual bonus incentive payments by achieving cost savings and meeting quality targets set by CMS in the demonstration that began in April 2005. In July 2007, CMS reported that in the first performance year (PY1), 2 participants earned combined bonuses of approximately $7.4 million, and all 10 achieved most of the quality targets. Congress mandated that GAO evaluate the demonstration. GAO examined, for PY1, the programs used, whether the design was reasonable, and the potential challenges in broadening the payment approach used in the demonstration to other physician groups. To do so, GAO reviewed CMS documents, surveyed all 10 groups, and conducted interviews and site visits."

A letter report issued by the Government Accountability Office with an abstract that begins "The outstanding amount of state and local government tax-exempt bonds has increased over the years. Congress is interested in whether the bonds are used for appropriate purposes since the federal government forgoes billions in tax revenues annually by excluding the bonds' interest from investors' federal gross income. Questions also exist over the bonds' borrowing costs as they can divert funds from the funded projects. This report (1) describes recent trends in tax exempt bonds, (2) provides information on the types of facilities financed with tax-exempt bonds, and (3) discusses borrowing costs considering the methods of selling bonds and compares issuance costs paid from bond proceeds for governmental and qualified private activity bonds. In addition to interviewing relevant officials, we analyzed IRS's Statistics of Income (SOI) data and data from Thomson Financial to address these objectives."

A letter report issued by the Government Accountability Office with an abstract that begins "In 2003, GAO found that many taxpayers' estimates of the value of their vehicles, claimed as tax deductions, were in excess of the charities' subsequent sales of the vehicles. Subsequently, effective January 1, 2005, the rules related to the amount taxpayers can claim as a deduction on their tax returns for vehicles donated to charities changed. Under the new rules, in many cases the amount taxpayers are allowed to claim as a deduction is less than they could have claimed before the changes. Some charities that used vehicle donations as a revenue source said that the changes could lead to fewer donated vehicles and reduced revenues. GAO was asked to determine how charities have been affected by the 2005 changes. GAO discussed the rule changes with Internal Revenue Service (IRS) officials and the impact of the changes with representatives of several charities. GAO judgmentally selected 10 charities from among the 65 contacted in the course of the 2003 GAO study. The experiences of these charities cannot be generalized to all charities because the selected charities were not drawn from a statistical sample of all charities with …

A letter report issued by the Government Accountability Office with an abstract that begins "Major disasters can disrupt transit operations, destroy vehicles and facilities, and impede the ability of people to reach essential relief and medical services and return to their homes and jobs. GAO determined (1) the federal role in assisting transit agencies after a major disaster; (2) the amounts, sources, and uses of federal disaster assistance for transit since 1998; (3) the factors that affected the timeliness and effectiveness of transit assistance after the 2005 Gulf Coast hurricanes; and (4) additional options for providing assistance to transit after a major disaster. GAO reviewed laws, regulations, and guidance; analyzed DOT and FEMA data; and interviewed officials with FEMA, DOT, state and local agencies, and others."

A letter report issued by the Government Accountability Office with an abstract that begins "The Federal Communications Commission (FCC) annually receives about 100,000 complaints from individuals and companies. FCC has the authority to investigate these complaints and take enforcement action if it finds a violation of the telecommunications laws and rules, which are designed to ensure, for example, that individuals have access to 911 services and a wider affordable range of communication services. As requested, this report reviews FCC's enforcement program and (1) summarizes the number and type of complaints received, investigations conducted, and enforcement actions taken by FCC from 2003 through 2006; (2) discusses how FCC assesses the impact of its enforcement program; and (3) discusses challenges FCC faces in providing complete and accurate information on its enforcement program. To address these objectives, GAO analyzed FCC's databases, interviewed FCC officials, telecommunications executives, and experts."

A letter report issued by the Government Accountability Office with an abstract that begins "Reducing aviation noise is important to the efficient operation and expansion of the National Airspace System because community opposition to aviation noise is a major obstacle to airport and runway development. Such development is needed to help address congestion and meet the nation's rapidly growing demand for air travel. The Federal Aviation Administration (FAA) and the National Aeronautics and Space Administration (NASA) have the primary federal responsibility for research and development (R&D) on aviation noise. FAA focuses on the impacts of aviation noise on communities, while NASA focuses on noise at its source--aircraft engines and airframes. Both FAA and NASA have set noise reduction goals. This congressionally requested report on aviation noise addresses (1) FAA's and NASA's R&D plans for addressing aviation noise and the extent to which they are aligned and (2) FAA's and NASA's noise reduction goals and the likelihood that these goals will be achieved. To conduct its work, GAO reviewed FAA's and NASA's R&D planning documents, coordinating mechanisms, and research plans and interviewed agency officials. In addition, aviation industry representatives reviewed and commented on a draft of this report. A draft was …

The Center for Extended Magnetohydrodynamic Modeling (CEMM) is developing computer simulation models for predicting the behavior of magnetically confined plasmas. Over the first phase of support from the Department of Energy’s Scientific Discovery through Advanced Computing (SciDAC) initiative, the focus has been on macroscopic dynamics that alter the confinement properties of magnetic field configurations. The ultimate objective is to provide computational capabilities to predict plasma behavior—not unlike computational weather prediction—to optimize performance and to increase the reliability of magnetic confinement for fusion energy. Numerical modeling aids theoretical research by solving complicated mathematical models of plasma behavior including strong nonlinear effects and the influences of geometrical shaping of actual experiments. The numerical modeling itself remains an area of active research, due to challenges associated with simulating multiple temporal and spatial scales. The research summarized in this report spans computational and physical topics associated with state of the art simulation of magnetized plasmas. The tasks performed for this grant are categorized according to whether they are primarily computational, algorithmic, or application-oriented in nature. All involve the development and use of the Non-Ideal Magnetohydrodynamics with Rotation, Open Discussion (NIMROD) code, which is described at http://nimrodteam.org. With respect to computation, we have tested and …

TMVOC-MP is a massively parallel version of the TMVOC code (Pruess and Battistelli, 2002), a numerical simulator for three-phase non-isothermal flow of water, gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous/fractured media. TMVOC-MP was developed by introducing massively parallel computing techniques into TMVOC. It retains the physical process model of TMVOC, designed for applications to contamination problems that involve hydrocarbon fuels or organic solvents in saturated and unsaturated zones. TMVOC-MP can model contaminant behavior under 'natural' environmental conditions, as well as for engineered systems, such as soil vapor extraction, groundwater pumping, or steam-assisted source remediation. With its sophisticated parallel computing techniques, TMVOC-MP can handle much larger problems than TMVOC, and can be much more computationally efficient. TMVOC-MP models multiphase fluid systems containing variable proportions of water, non-condensible gases (NCGs), and water-soluble volatile organic chemicals (VOCs). The user can specify the number and nature of NCGs and VOCs. There are no intrinsic limitations to the number of NCGs or VOCs, although the arrays for fluid components are currently dimensioned as 20, accommodating water plus 19 components that may be either NCGs or VOCs. Among them, NCG arrays are dimensioned as 10. The user may select …

Although electrokinetic effects are not new, only recently have they been investigated for possible use in energy conversion devices. We have recently reported the electrokinetic generation of molecular hydrogen from rapidly flowing liquid water microjets [Duffin et al. JPCC 2007, 111, 12031]. Here, we describe the use of liquid water microjets for direct conversion of electrokinetic energy to electrical power. Previous studies of electrokinetic power production have reported low efficiencies ({approx}3%), limited by back conduction of ions at the surface and in the bulk liquid. Liquid microjets eliminate energy dissipation due to back conduction and, measuring only at the jet target, yield conversion efficiencies exceeding 10%.

Stimulated sulfate-reduction is a bioremediation technique utilized for the sequestration of heavy metals in the subsurface.We performed laboratory column experiments to investigate the geoelectrical response of iron sulfide transformations by Desulfo vibriovulgaris. Two geoelectrical methods, (1) spectral induced polarization (SIP), and (2) electrodic potential measurements, were investigated. Aqueous geochemistry (sulfate, lactate, sulfide, and acetate), observations of precipitates (identified from electron microscopy as iron sulfide), and electrodic potentials on bisulfide ion (HS) sensitive silver-silver chloride (Ag-AgCl) electrodes (630 mV) were diagnostic of induced transitions between an aerobic iron sulfide forming conditions and aerobic conditions promoting iron sulfide dissolution. The SIP data showed 10m rad anomalies during iron sulfide mineralization accompanying microbial activity under an anaerobic transition. These anomalies disappeared during iron sulfide dissolution under the subsequent aerobic transition. SIP model parameters based on a Cole-Cole relaxation model of the polarization at the mineral-fluid interface were converted to (1) estimated biomineral surface area to pore volume (Sp), and (2) an equivalent polarizable sphere diameter (d) controlling the relaxation time. The temporal variation in these model parameters is consistent with filling and emptying of pores by iron sulfide biofilms, as the system transitions between anaerobic (pore filling) and aerobic (pore emptying) conditions. The …

A recent independent review led to uncertainty about the technical basis for characterizing the residual amount of tritium in polymer components used in the Savannah River Site Tritium Facilities that are sent for waste disposal. A review of a paper published in the open literature firmly establishes the basis of the currently used characterization, 10 Ci/cc. Information provided in that paper about exposure experiments performed at the DOE Mound Laboratory allows the calculation of the currently used characterization. These experiments involved exposure of high density polyethylene (HD-PE) to initially 1 atm tritium gas. In addition, a review of recent research at the Savannah River Site not only further substantiates this characterization, but also establishes its use for ultra-high molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, a trade name is Teflon{reg_sign}), and Vespel{reg_sign} polyimide. 10 Ci/cc tritium is a representative characterization for any type of polymer components exposed at ambient temperature and at approximately 1 atm. tritium gas.

The project entitled 'Scaleable Clean Aluminum Melting Systems' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Secat Inc. The three-year project was initially funded for the first year and was then canceled due to funding cuts at the DOE headquarters. The limited funds allowed the research team to visit industrial sites and investigate the status of using immersion heaters for aluminum melting applications. Primary concepts were proposed on the design of furnaces using immersion heaters for melting. The proposed project can continue if the funding agency resumes the funds to this research. The objective of this project was to develop and demonstrate integrated, retrofitable technologies for clean melting systems for aluminum in both the Metal Casting and integrated aluminum processing industries. The scope focused on immersion heating coupled with metal circulation systems that provide significant opportunity for energy savings as well as reduction of melt loss in the form of dross. The project aimed at the development and integration of technologies that would enable significant reduction in the energy consumption and environmental impacts of melting aluminum through substitution of immersion heating for the conventional radiant burner methods used in reverberatory furnaces. Specifically, the …

Very large multidimensional arrays are commonly used in data intensive scientific computations as well as on-line analytical processingapplications referred to as MOLAP. The storage organization of such arrays on disks is done by partitioning the large global array into fixed size sub-arrays called chunks or tiles that form the units of data transfer between disk and memory. Typical queries involve the retrieval of sub-arrays in a manner that access all chunks that overlap the query results. An important metric of the storage efficiency is the expected number of chunks retrieved over all such queries. The question that immediately arises is"what shapes of array chunks give the minimum expected number of chunks over a query workload?" The problem of optimal chunking was first introduced by Sarawagi and Stonebraker who gave an approximate solution. In this paper we develop exact mathematical models of the problem and provide exact solutions using steepest descent and geometric programming methods. Experimental results, using synthetic and real life workloads, show that our solutions are consistently within than 2.0percent of the true number of chunks retrieved for any number of dimensions. In contrast, the approximate solution of Sarawagi and Stonebraker can deviate considerably from the true result with …

In case of porous fluid-saturated medium the Biot's poroelasticity theory predicts a movement of the pore fluid relative to the skeleton on seismic wave propagation through the medium. This phenomenon opens an opportunity for investigation of the flow properties of the hydrocarbon-saturated reservoirs. It is well known that relative fluid movement becomes negligible at seismic frequencies if porous material is homogeneous and well cemented. In this case the theory predicts an underestimated seismic wave velocity dispersion and attenuation. Based on Biot's theory, Helle et al. (2003) have numerically demonstrated the substantial effects on both velocity and attenuation by heterogeneous permeability and saturation in the rocks. Besides fluid flow effect, the effects of scattering (Gurevich, et al., 1997) play very important role in case of finely layered porous rocks and heterogeneous fluid saturation. We have used both fluid flow and scattering effects to derive a frequency-dependent seismic attribute which is proportional to fluid mobility and applied it for analysis of reservoir permeability.

Proton exchange membrane fuel cells are expected to change the landscape of power generation over the next ten years. For this to be realized one of the most significant challenges to be met for stationary systems is lifetime, where 40,000 hours of operation with less than 10% decay is desired. This project conducted fundamental studies on the durability of membrane electrode assemblies (MEAs) and fuel cell stack systems with the expectation that knowledge gained from this project will be applied toward the design and manufacture of MEAs and stack systems to meet DOE’s 2010 stationary fuel cell stack systems targets. The focus of this project was PEM fuel cell durability – understanding the issues that limit MEA and fuel cell system lifetime, developing mitigation strategies to address the lifetime issues and demonstration of the effectiveness of the mitigation strategies by system testing. To that end, several discoveries were made that contributed to the fundamental understanding of MEA degradation mechanisms. (1) The classically held belief that membrane degradation is solely due to end-group “unzipping” is incorrect; there are other functional groups present in the ionomer that are susceptible to chemical attack. (2) The rate of membrane degradation can be greatly slowed …

Small animal SPECT imaging systems have multiple potential applications in biomedical research. Whereas SPECT data are commonly interpreted qualitatively in a clinical setting, the ability to accurately quantify measurements will increase the utility of the SPECT data for laboratory measurements involving small animals. In this work, we assess the effect of photon attenuation, scatter and partial volume errors on the quantitative accuracy of small animal SPECT measurements, first with Monte Carlo simulation and then confirmed with experimental measurements. The simulations modeled the imaging geometry of a commercially available small animal SPECT system. We simulated the imaging of a radioactive source within a cylinder of water, and reconstructed the projection data using iterative reconstruction algorithms. The size of the source and the size of the surrounding cylinder were varied to evaluate the effects of photon attenuation and scatter on quantitative accuracy. We found that photon attenuation can reduce the measured concentration of radioactivity in a volume of interest in the center of a rat-sized cylinder of water by up to 50percent when imaging with iodine-125, and up to 25percent when imaging with technetium-99m. When imaging with iodine-125, the scatter-to-primary ratio can reach up to approximately 30percent, and can cause overestimation of …

Over the past half-century, the Applied Mathematics program in the U.S. Department of Energy's Office of Advanced Scientific Computing Research has made significant, enduring advances in applied mathematics that have been essential enablers of modern computational science. Motivated by the scientific needs of the Department of Energy and its predecessors, advances have been made in mathematical modeling, numerical analysis of differential equations, optimization theory, mesh generation for complex geometries, adaptive algorithms and other important mathematical areas. High-performance mathematical software libraries developed through this program have contributed as much or more to the performance of modern scientific computer codes as the high-performance computers on which these codes run. The combination of these mathematical advances and the resulting software has enabled high-performance computers to be used for scientific discovery in ways that could only be imagined at the program's inception. Our nation, and indeed our world, face great challenges that must be addressed in coming years, and many of these will be addressed through the development of scientific understanding and engineering advances yet to be discovered. The U.S. Department of Energy (DOE) will play an essential role in providing science-based solutions to many of these problems, particularly those that involve the energy, …

Many tools that target parallel and distributed environments must co-locate a set of daemons with the distributed processes of the target application. However, efficient and portable deployment of these daemons on large scale systems is an unsolved problem. We overcome this gap with LaunchMON, a scalable, robust, portable, secure, and general purpose infrastructure for launching tool daemons. Its API allows tool builders to identify all processes of a target job, launch daemons on the relevant nodes and control daemon interaction. Our results show that Launch-MON scales to very large daemon counts and substantially enhances performance over existing ad hoc mechanisms.

The H-02 Wetland Treatment System (Figure 1) is used to remove heavy metals (e.g., copper and zinc) from the H-Area process and storm water discharge. Routine flow enters an equalization basin by inlets on either the east (Location 1) or west end (Location 2). The west end influent constitutes 75% of the average flow into the basin which has an average residence time of approximately 3 days at low pool (i.e., 120 gal/min. through a volume of 0.5 million gallons). The water then exits via the basin outlet on the east end. Next, the water flows to a splitter box (Location 3) which evenly separates the flow between two wetland cells for a design flow of 60 gal/min. per wetland cell with a residence time in the cell of approximately 2 days. The wetland effluent is then combined (Location 4) and flows through a spillway before reaching the National Pollution Discharge Elimination System (NPDES) measurement point near Road 4. During initial operation, it was observed that the pH of the water leaving the equalization basin was elevated compared to the influent pH. Furthermore, the elevated pH remained through the wetland cells so that there was an average pH of 10 …

This report discusses the polar bear status and they are affected by climate change, contaminants, and subsistence and sport hunting.

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This report describes the FY2008 appropriations for the Department of Homeland Security.. The Administration requested a net appropriation of $35.5 billion in net budget authority for FY2008. This report is a guide to one of the regular appropriations bills that Congress considers each year. It is designed to supplement the information provided by the House and Senate Appropriations Subcommittees on Homeland Security.

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Crosswell seismic acquisition provides an ideal geometry for monitoring travel time changes in the subsurface. Analysis of delay time in terms of a characteristic frequency allows us to estimate optimal acquisition parameters (frequency and distance). We have deployed standard data acquisition equipment for continuous monitoring of crosswell travel time in two separate field experiments, with well spacing of 3 and 30 m. The acquisition hardware used for the field experiments is described, along with environmental effects (such as temperature) that influence the measurements. Two field experiments are described that correlate changes in travel time (and therefore velocity) with changes in barometric pressure. The results from the two field sites show a pressure sensitivity for velocity of 10{sup -6}/Pa to 10{sup -8}/Pa.