The {sup 207}Pb/{sup 235}U ages for 14 subsamples of opal or chalcedony layers younger than calcite formed at elevated temperature range between 1.88 {+-} 0.05 and 9.7 {+-} 1.5 Ma with most values older than 6-8 Ma. These data indicate that fluids with elevated temperatures have not been present in the unsaturated zone at Yucca Mountain since about 1.9 Ma and most likely since 6-8 Ma. Discordant U-Pb isotope data for chalcedony subsamples representing the massive silica stage in the formation of the coatings are interpreted using a model of the diffusive loss of U decay products. The model gives an age estimate for the time of chalcedony formation around 10-11 Ma, which overlaps ages of clay minerals formed in tuffs below the water table at Yucca Mountain during the Timber Mountain thermal event.

It is often argued that paleoclimate studies are necessary to determine whether climate models and their predictions of future climate change can be trusted. An overall measure of the sensitivity of global mean surface temperature to a given radiative perturbation is provided by the global climate sensitivity parameter. In climate model experiments, this parameter appears to be moderately independent of the cause of the perturbation [see, for example, Hansen et al. (1997) and Hewitt and Mitchell (1997)], but it may differ from one model to the next by as much as a factor of three (IPCC, 1995). Moreover, there are some scientists who claim that all models are much more sensitive than the climate system itself (Lindzen, 1997). Thus it would be valuable to determine which models (if any) are consistent with the paleoclimate record and what factors are responsible for model differences in sensitivity. In an analysis of the Paleoclimate Modeling Intercomparison Project (PMIP) simulations of the Last Glacial Maximum (LGM) of 21,000 years ago, we have calculated how the ''forcing'' and feedbacks determine the climatic response. In the PMIP context, the ice sheet distribution is prescribed and the resulting increase in planetary albedo is the most important ''forcing'' …

Large distributed systems such as Computational/Data Grids require large amounts of data to be co-located with the computing facilities for processing. Ensuring that the data is there in time for the computation in today's Internet is a massive problem. From our work developing a scalable distributed network cache, we have gained experience with techniques necessary to achieve high data throughput over high bandwidth Wide Area Networks (WAN). In this paper, we discuss several hardware and software design techniques and issues, and then describe their application to an implementation of an enhanced FTP protocol called GridFTP. We also describe results from two applications using these techniques, which were obtained at the Supercomputing 2000 conference.

Epitaxial, conductive-oxide buffer layers having bilayer configurations have been deposited on biaxially textured nickel substrates (RABiTS) by rf and dc-sputter techniques. The conductive bilayer structures comprise the layer sequences of SrRuO{sub 3}/LaNiO{sub 3}/Ni and SrRuO{sub 3}/Cu/Ni. Systematic property characterizations of the buffer layers showed excellent electrical and structural properties. High-quality epitaxial YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films grown by pulsed-laser deposition on these structures exhibited critical current densities (J{sub c}) as high as 1.3 x 10{sup 6} A/cm{sup 2} at 77 K in self-field.

We investigate the properties of interference fragmentation functions arising from the emission of two leading hadrons inside the same jet for inclusive lepton-nucleon deep inelastic scattering. Using an extended spectator model for the mechanism of the hadronization, we give a complete calculation and numerical estimates for the examples of a proton-pion pair produced with invariant mass on the Roper resonance, and of two pions produced with invariant mass close to the {rho} mass. We discuss azimuthal angular dependence of the leading order cross section to point up favourable conditions for extracting transversity from experimental data.

None

By de-emphasizing the print journal collection our organization has been able to accomplish several goals: provide access to additional digital resources through cost savings; support customers' requirements for information at the desktop; reduce staff costs; free staff time for higher level tasks; and reduce space costs. Print journal cancellations have now become incorporated into the regular routine of our library. We have a proven process in place that we can rely on to provide sound decisions. We have been aided in our successful accomplishments by the enormous support of our customers, our Library Advisory Board and laboratory management. Opportunities and challenges will continue to present themselves as our organization continues to emphasize digital resources over print.

Light-duty chassis dynamometer driving cycle tests were conducted on a Mercedes A170 diesel vehicle with various sulfur-level fuels and exhaust emission control systems. Triplicate runs of a modified light-duty federal test procedure (FTP), US06 cycle, and SCO3 cycle were conducted with each exhaust configuration and fuel. Ultra-low sulfur (3-ppm) diesel fuel was doped to 30- and 150-ppm sulfur so that all other fuel properties remained the same. The fuels used in these experiments met the specifications of the fuels from the DECSE (Diesel Emission Control Sulfur Effects) program. Although the Mercedes A170 vehicle is not available in the US, its emissions in the as tested condition fell within the U.S. Tier 1 full useful life standards with the OEM catalysts installed. Tests with the OEM catalysts removed showed that the OEM catalysts reduced PM emissions from the engine-out condition by 30-40% but had negligible effects on NOx emissions. Fuel sulfur level had very little effect on th e OEM catalyst performance. A prototype catalyzed diesel particulate filter (CDPF) mounted in an underfloor configuration reduced particulate matter emissions by more than 90% compared to the factory emissions control system. The results show that the CDPF did not promote any significant amounts …

The increased use of object-oriented toolkits in large-scale scientific simulation presents new opportunities and challenges for the use of automatic (or algorithmic) differentiation (AD) techniques, especially in the context of optimization. Because object-oriented toolkits use well-defined interfaces and data structures, there is potential for simplifying the AD process. Furthermore, derivative computation can be improved by exploiting high-level information about numerical and computational abstractions. However, challenges to the successful use of AD with these toolkits also exist. Among the greatest challenges is balancing the desire to limit the scope of the AD process with the desire to minimize the work required of a user. They discuss their experiences in integrating AD with the PETSc, PVODE, and TAO toolkits and the plans for future research and development in this area.

None

Cleanrooms, critical to a wide range of industries, universities, and government facilities, are extremely energy intensive. Consequently, energy represents a significant operating cost for these facilities. Improving energy efficiency in cleanrooms will yield dramatic productivity improvement. But more importantly to the industries which rely on cleanrooms, base load reduction will also improve reliability. The number of cleanrooms in the US is growing and the cleanroom environmental systems' energy use is increasing due to increases in total square footage and trends toward more energy intensive, higher cleanliness applications. In California, many industries important to the State's economy utilize cleanrooms. In California these industries utilize over 150 cleanrooms with a total of 4.2 million sq. ft. (McIlvaine). Energy intensive high tech buildings offer an attractive incentive for large base load energy reduction. Opportunities for energy efficiency improvement exist in virtually all operating cleanrooms as well as in new designs. To understand the opportunities and their potential impact, Pacific Gas and Electric Company sponsored a project to benchmark energy use in cleanrooms in the electronics (high-tech) and biotechnology industries. Both of these industries are heavily dependent intensive cleanroom environments for research and manufacturing. In California these two industries account for approximately 3.6 million …

Diagnostic software tools for large commercial buildings are being developed to help detect and diagnose energy and other performance problems with building operations. These software applications utilize energy management control system (EMCS) trend log data. Due to the recent development of diagnostic tools, there has been little detailed comparison among the tools and a limited awareness of tool capabilities by potential users. Today, these diagnostic tools focus mainly on air handlers, but the opportunity exists for broadening the scope of the tools to include all major parts of heating, cooling, and ventilation systems in more detail. This paper compares several tools in the following areas: (1) Scope, intent, and background; (2) Data acquisition, pre-processing, and management; (3) Problems detected; (4) Raw data visualization; (5) Manual and automated diagnostic methods and (6) Level of automation. This comparison is intended to provide practitioners and researchers with a picture of the current state of diagnostic tools. There is tremendous potential for these tools to help improve commercial building energy and non-energy performance.

Gold Basin is a large L4 chondrite shower, that was recently discovered in the Mojave Desert, Arizona [1]. Based on {sup 109}Be and {sup 14}C concentrations in several fragments, the pre-atmospheric radius of this shower was estimated to be 3-4 meters [2]. Among chondrites, Gold Basin is one of the largest, thus providing a unique opportunity for comparing measured cosmogenic nuclide concentrations with model calculations for large objects. Noble gas measurements combined with {sup 10}Be data of most Gold Basin samples suggest a single-stage exposure of 15-30 Myr, although a few samples may require a complex exposure history [3]. We selected eight samples of the Gold Basin shower that were analyzed for noble gases; these samples represent a wide range of shielding depths.

In this paper we discuss the conceptual design of a low-{beta} superconducting proton linac based on multi-gap spoke resonator structures. We have demonstrated the feasibility of using superconducting accelerating structures throughout a proton linac for high-peak current applications. The injection energy for this linac is assumed to be 6.7 MeV, which equals the output energy of the CW RFQ built for the Low-Energy Demonstration Accelerator now operating at Los Alamos. The beam is accelerated to 109 MeV using multi-gap spoke resonators. Both 2-gap and 3-gap cavities are used in three accelerating sections with geometric-{beta} values of 0.175, 0.2, and 0.34. Higher beam energies can be achieved by transitioning to elliptical superconducting cavities to further accelerate the beam. Preliminary beam-dynamics simulation results are shown and discussed.

We discuss concurrent multiscale simulations of dynamic and temperature-dependent processes found in nanomechanical systems coupled to larger scale surroundings. We focus on the behavior of sub-micron Micro-Electro-Mechanical Systems (MEMS), especially micro-resonators. The coupling of length scales methodology we have developed for MEMS employs an atomistic description of small but key regions of the system, consisting of millions of atoms, coupled concurrently to a finite element model of the periphery. The result is a model that accurately describes the behavior of the mechanical components of MEMS down to the atomic scale. This paper reviews some of the general issues involved in concurrent multiscale simulation, extends the methodology to metallic systems and describes how it has been used to identify atomistic effects in sub-micron resonators.

None

We construct renormalizable, asymptotically free, four dimensional gauge theories that dynamically generate a fifth dimension.

A major goal of experimental particle physics over the next decade is to measure the sides and angles of the Unitarity triangle redundantly, and as precisely as possible. Overconstraining the triangle will test the Cabbibo-Kobayashi-Maskawa model of quark mixing. The CDF collaboration, due to begin a second run in March 2001 with major upgrades to both the accelerator and the detector, will study the angle {beta} using B{sup 0} decays, the angle {gamma} using B{sup 0} and B{sub s}{sup 0} decays, and a side of the triangle through the observation of B{sub s}{sup 0}--{bar B}{sub s}{sup 0} mixing. Projected sensitivities are driven mostly by previous measurements using data from the first run. One highlight of the Run I B physics program is a measurement of the CP violating parameter sin 2{beta} = 0.79{sub {minus}0.44}{sup +0.41}, based on a tagged sample of 400 B{sup 0} decays in the mode B{sub 0}/{bar B}{sup 0} {r_arrow} J/{psi}K{sub s}{sup 0}. The technology of flavor tagging, used here as well as in numerous B{sup 0}-{bar B}{sup 0} mixing analyses in run I, is crucial and will be augmented in Run II with better particle identification capabilities. Exclusive all-hadronic final states will enter the data sample …

This article describes the crystal structure of 1,3-bis(hydroxymethyl)-2-oxaadamantane, C₁₁H₁₈O₃.

The electricity supply system is undergoing major regulatory and technological change with significant implications for the way in which the sector will operate (including its patterns of carbon emissions) and for the policies required to ensure socially and environmentally desirable outcomes. One such change stems from the rapid emergence of viable small-scale (i.e., smaller than 500 kW) generators that are potentially competitive with grid delivered electricity, especially in combined heat and power configurations. Such distributed energy resources (DER) may be grouped together with loads in microgrids. These clusters could operate semi-autonomously from the established power system, or macrogrid, matching power quality and reliability more closely to local end-use requirements. In order to establish a capability for analyzing the effect that microgrids may have on typical commercial customers, such as office buildings, restaurants, shopping malls, and grocery stores, an economic mod el of DER adoption is being developed at Berkeley Lab. This model endeavors to indicate the optimal quantity and type of small on-site generation technologies that customers could employ given their electricity requirements. For various regulatory schemes and general economic conditions, this analysis produces a simple operating schedule for any installed generators. Early results suggest that many commercial customers can …

PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine), a mutagen/carcinogen belonging to the class of heterocyclic amines (HCAs) found in cooked meats, is a mammary gland carcinogen in rats and has been implicated in the etiology of certain human cancers including breast cancer. To gain insight into the genomic alterations associated with PhIP-induced mammary gland carcinogenesis, we used comparative genomic hybridization (CGH) to examine chromosomal abnormalities in rat mammary carcinomas induced by PhIP, and for comparison, by DMBA (7,12-dimethylbenz[a]anthracene), a potent experimental mammary carcinogen. There was a consistent and characteristic pattern of chromosome-region loss in PhIP-induced carcinomas that clearly distinguished them from carcinomas induced by DMBA.

This document describes the results of consensus agreements reached by the DARHT Safety Planning Team during the development of the update of the DARHT Safety Analysis Document (SAD). The SAD is one of the Authorization Basis (AB) Documents required by the Department prior to granting approval to operate the DARHT Facility. The DARHT Safety Planning Team is lead by Mr. Joel A. Baca of the Department of Energy Albuquerque Operations Office (DOE/AL). Team membership is drawn from the Department of Energy Albuquerque Operations Office, the Department of Energy Los Alamos Area Office (DOE/LAAO), and several divisions of the Los Alamos National Laboratory. Revision 1 of the DARHT SAD had been written as part of the process for gaining approval to operate the Phase 1 (First Axis) Accelerator. Early in the planning stage for the required update of the SAD for the approval to operate both Phase 1 and Phase 2 (First Axis and Second Axis) DARHT Accelerator, it was discovered that a conflict existed between the Laboratory approach to describing the management of facility and worker safety.

This paper will present a survey of the current published work and products available to do off-line data mining for computer network security information. Hundreds of megabytes of data are collected every second that are of interest to computer security professionals. This data can answer questions ranging from the proactive, ''Which machines are the attackers going to try to compromise?'' to the reactive, ''When did the intruder break into my system and how?'' Unfortunately, there's so much data that computer security professionals don't have time to sort through it all. What we need are systems that perform data mining at various levels on this corpus of data in order to ease the burden of the human analyst. Such systems typically operate on log data produced by hosts, firewalls and intrusion detection systems as such data is typically in a standard, machine readable format and usually provides information that is most relevant to the security of the system. Systems that do this type of data mining for security information fall under the classification of intrusion detection systems. It is important to point out that we are not surveying real-time intrusion detection systems. Instead, we examined what is possible when the analysis …

Non-homologous end joining (NHEJ) is a major pathway for the repair of DNA double-strand breaks in mammalian cells. DNA-dependent protein kinase (DNA-PK), ligase IV, and XRCC4 are all critical components of the NHEJ repair pathway. DNA-PK is composed of a heterodimeric DNA-binding component, Ku, and a large catalytic subunit, DNA-PKcs. Ligase IV and XRCC4 associate to form a multimeric complex that is also essential for NHEJ. DNA-PK and ligase IV/XRCC4 interact at DNA termini which results in stimulated ligase activity. Here we define interactions between the components of these two essential complexes, DNA-PK and ligase IV/XRCC4. We find that ligase IV/XRCC4 associates with DNA-PK in a DNA-independent manner. The specific protein-protein interactions that mediate the interaction between these two complexes are further identified. Direct physical interactions between ligase IV and Ku as well as between XRCC4 and DNA-PKcs are shown. No direct interactions are observed between ligase IV and DNA-PKcs or between XRCC4 and Ku. Our data defines the specific protein pairs involved in the association of DNA-PK and ligase IV/XRCC4, and suggests a molecular mechanism for coordinating the assembly of the DNA repair complex at DNA breaks.