High-convergence ignition-like double-shell implosion experiments have been performed on the Omega laser facility [T.R. Boehly et al., Opt. Commun. 133, 495 (1997)] using cylindrical gold hohlraums with 40 drive beams. Repeatable, dominant primary (2.45 MeV) neutron production from the mix-susceptible compressional phase of a double-shell implosion, using fall-line design optimization and exacting fabrication standards, is experimentally inferred from time-resolved core x-ray imaging. Effective control of fuel-pusher mix during final compression is essential for achieving noncryogenic ignition with double-shell targets on the National Ignition Facility [Paisner et al., Laser Focus World 30, 75 (1994)].

The Cosmic Microwave Background (CMB) is a snapshot of the Universe some 400,000 years after the Big Bang. The pattern of anisotropies in the CMB carries a wealth of information about the fundamental parameters of cosmology. Extracting this information is an extremely computationally expensive endeavor, requiring massively parallel computers and software packages capable of exploiting them. One such package is the Microwave Anisotropy Dataset Computational Analysis Package (MADCAP) which has been used to analyze data from a number of CMB experiments. In this work, we compare MADCAP performance on the vector-based Earth Simulator (ES) and Cray X1 architectures and two leading superscalar systems, the IBM Power3 and Power4. Our results highlight the complex interplay between the problem size, architectural paradigm, interconnect, and vendor-supplied numerical libraries, while isolating the I/O file system as the key bottleneck across all the platforms.

Triplication of a wavefront, also classically known as birefringence, can and does occur in transversely isotropic (TI) media. With the growing interest in shear waves, and in particular, converted shear waves, it becomes necessary to study this phenomenon, and the bright spots that accompany it. In a plane that includes the medium's rotational symmetry axis, there may exist a range of angles within which the qSV wave, whose polarization lies in that plane, may propagate at three distinct velocities. The region of the qSV wave curve where this can occur always corresponds to the region of the qSV slowness curve where the closed qSV curve about the origin is concave. When the range of angles is small and the three arrivals are close together, the usual situation, the qSV wave within that small range will be significantly brighter than in other directions. When the range of angles is large, the two cusps of the wave surface, on the borders of the region of triplication will both be bright spots.

Computational grids have the potential for solving large-scale scientific problems using heterogeneous and geographically distributed resources. However, a number of major technical hurdles must be overcome before this goal can be fully realized. One problem critical to the effective utilization of computational grids is efficient job scheduling. Our prior work addressed this challenge by defining a grid scheduling architecture and several job migration strategies. The focus of this study is to explore the impact of data migration under a variety of demanding grid conditions. We evaluate our grid scheduling algorithms by simulating compute servers, various groupings of servers into sites, and inter-server networks, using real workloads obtained from leading supercomputing centers. Several key performance metrics are used to compare the behavior of our algorithms against reference local and centralized scheduling schemes. Results show the tremendous benefits of grid scheduling, even in the presence of input/output data migration - while highlighting the importance of utilizing communication-aware scheduling schemes.

I'd like to welcome you to the Agent 2004 conference. As most of you are aware, this conference is the fifth in a series of meetings that began in 1999. A conference followed the next year in 2000. The 2001 conference was skipped because of some conflicts with other conferences, and the conferences have proceeded annually since then. We have the proceedings of the previous conferences available here on CDs. One CD has the proceedings from 1999, 2000, and 2002; the other contains last year's proceedings. The purpose of these conferences is to advance the state of the computational social sciences and to integrate the social sciences with the decision sciences and something that is traditionally known as the management sciences. Those of you in the operations/research area are familiar with the traditional school of modeling simulation that emerged from that scientific area. This conference will bring together a different group of people to talk about the topic of agent-based theories and simulations. This fifth agent conference is one of a group of conferences held annually around the country. Most of you are probably aware of the CASOS Conference held at Carnegie Mellon University, usually in July. UCLA holds the …

The recently generated database of microbial genes from anoligotrophic environment populated by a calculated 1,800 of major phylotypes (the Sargasso Sea metagenome) presents a great source for expanding local databases of genes indicative of a specific function. In this paper we analyze the Sargasso Sea metagenome in terms of the presence of methanopterin-linked C1 transfer genes that are signature for methylotrophy. We conclude that more than 10 phylotypes possessing genes of interest are present in this environment, and a few of these are relatively abundant species. The sequences representative of the major phylotypes do not appear to belong to any known microbial group capable of methanopterin-linked C1 transfer. Instead, they separate from all known sequences on phylogenetic trees, pointing towards their affiliation with a novel microbial phylum. These data imply a broader distribution of methanopterin-linked functions in the microbial world than previously known.

The challenges of increased technological demands in today's workplace require virtually all workers to develop higher-order cognitive skills including problem solving and systems thinking in order to be productive. Such ''habits of mind'' are viewed as particularly critical for success in the information-based workplace, which values reduced hierarchy, greater worker independence, teamwork, communications skills, non-routine problem solving, and understanding of complex systems. The need is particularly compelling in the buildings arena. To scope the problem, this paper presents the results of interviews and focus groups--conducted by Oakland California's Peralta Community College District and Lawrence Berkeley National Laboratory--in which approximately 50 industry stakeholders discussed contemporary needs for building operator education at the community college level. Numerous gaps were identified between the education today received by building operators and technicians and current workplace needs. The participants concurred that many of the problems seen today in achieving and maintaining energy savings in buildings can be traced to inadequacies in building operation and lack of awareness and knowledge about how existing systems are to be used, monitored, and maintained. Participants and others we interviewed affirmed that while these issues are addressed in various graduate-level and continuing education programs, they are virtually absent at the …

Polymer injection has been used in reservoirs to alleviate contrasting permeability zones to enhance oil recovery (EOR). Polymer technology relies mainly on the use of polyacrylamides cross-linked by a hazardous metal or organic. Contemporary polymer plugging has investigated the stimulation of in-situ microorganisms to produce polymers (Jenneman et. al., 2000) and the use of biocatalysts to trigger gelling (Bailey et. al., 2000). The use of biological polymers are advantageous in that they can block high permeability areas, are environmentally friendly, and have potential to form reversible gels without the use of hazardous cross-linkers. Recent efforts have produced a reactive alkaline-soluble biopolymer from Agrobacterium species ATCC # 31749 that gels upon decreasing the pH of the polymeric solution. Microbial polymers are of interest due to their potential cost savings, compared to conventional use of synthetic chemical polymers. Numerous microorganisms are known to produce extracellular polysaccharides. One microbiological polymer of interest is curdlan, â - (1, 3) glucan, which has demonstrated gelling properties by a reduction in pH. The focus of this study was to determine the impact an alkaline-soluble biopolymer can have on sandstone permeability.

Production increases in intensively managed forests have been obtained by improving resource availability through water and nutrient amendments. Increased stem production has been attributed to shifts in growth from roots to shoot, and such shifts would have important implications for below ground carbon sequestration. We examined above and below ground growth and biomass accumulation and distribution in two eastern cottonwood clones and American sycamore receiving irrigation(I), fertilization(F), orirrigation+fertilization(IF) and compared with non-treated controls(C). Above ground growth and biomass accumulation responded positively to both I and F in all genotypes. After three growing seasons, the largest trees were sycamore receiving the IF treatment, with a total mean annual biomass production of 9.4 Mg ha -1 yr -1. Total cottonwood mean annual biomass production in both clones was >5.0 Mg ha -1 yr -1 in the IF treatment. Above ground biomass production was 6.3 and >3.1 Mg ha -1 yr -1 for sycamore and cottonwoods, respectively. Total root mass fraction was lower in high resource treatments and declined as stands aged. To compare allocation in trees of equal size, we used allometric relationships between above and below ground tissue. Allometric relationships between woody perennial tissues rarely differed among treatments. Improved resource availability …

Because of their intrinsic brightness, supernovae make excellent cosmological probes. We describe the spectral-fitting expanding atmosphere method (SEAM) for obtaining distances to Type IIP supernovae (SNe IIP) and present a distance to SN 1999em for which a Cepheid distance exists. Our models give results consistent with the Cepheid distance, even though we have not attempted to tune the underlying hydrodynamical model but have simply chosen the best fits. This is in contradistinction to the expanding photosphere method (EPM), which yields a distance to SN 1999em that is 50 percent smaller than the Cepheid distance. We emphasize the differences between the SEAM and the EPM. We show that the dilution factors used in the EPM analysis were systematically too small at later epochs. We also show that the EPM blackbody assumption is suspect. Since SNe IIP are visible to redshifts as high as z {approx}< 6, with the James Webb Space Telescope, the SEAM may be a valuable probe of the early universe.

To determine prospectively whether physical activity canprevent age-related weight gain and whether changing levels of activityaffect body weight. DESIGN/SUBJECTS: The study consisted of 8,080 maleand 4,871 female runners who completed two questionnaires an average(+/-standard deviation (s.d.)) of 3.20+/-2.30 and 2.59+/-2.17 yearsapart, respectively, as part of the National Runners' Health Study.RESULTS: Changes in running distance were inversely related to changes inmen's and women's body mass indices (BMIs) (slope+/-standard error(s.e.): -0.015+/-0.001 and -0.009+/-0.001 kg/m(2) per Deltakm/week,respectively), waist circumferences (-0.030+/-0.002 and -0.022+/-0.005 cmper Deltakm/week, respectively) and percent changes in body weight(-0.062+/-0.003 and -0.041+/-0.003 percent per Deltakm/week,respectively, all P<0.0001). The regression slopes were significantlysteeper (more negative) in men than women for DeltaBMI and Deltapercentbody weight (P<0.0001). A longer history of running diminishedthe impact of changing running distance on men's weights. When adjustedfor Deltakm/week, years of aging in men and years of aging in women wereassociated with increases of 0.066+/-0.005 and 0.056+/-0.006 kg/m(2) inBMI, respectively, increases of 0.294+/-0.019 and 0.279+/-0.028 percentin Delta percentbody weight, respectively, and increases of 0.203+/-0.016and 0.271+/-0.033 cm in waist circumference, respectively (allP<0.0001). These regression slopes suggest that vigorous exercise mayneed to increase 4.4 km/week annually in men and 6.2 km/week annually inwomen to compensate for the expected gain in weight associated …

We report sharp spin-dependent energy loss features in electron scattering from bcc Fe(100) thin films grown on Ag(100). Majority spin features are observed at {approx}1.8 and 2.5 eV energy loss, and a minority spin feature is observed at {approx}2.0 eV energy loss. The majority spin peaks are attributed to spin-flip exchange scattering from the Fe films, with the lowest energy feature corresponding to the exchange splitting for the Fe. The minority spin peak is attributed to non-flip exchange scattering with an energy corresponding to the separation between occupied and unoccupied minority spin bands.

The finding of algorithms for factoring and data base search that promise substantially increased computational power, as well as the expectation for efficient simulation of quantum systems have spawned an intense interest in the realization of quantum information processors [1]. Solid state implementations of quantum computers scaled to &gt;1000 quantum bits ('qubits') promise to revolutionize information technology, but requirements with regard to sources of decoherence in solid state environments are sobering. Here, we briefly review basic approaches to impurity spin based qubits and present progress in our effort to form prototype qubit test structures. Since Kane's bold silicon based spin qubit proposal was first published in 1998 [2], several groups have taken up the challenge of fabricating elementary building blocks [3-5], and several exciting variations of single donor qubit schemes have emerged [6]. Single donor atoms, e. g. {sup 31}P, are 'natural quantum dots' in a silicon matrix, and the spins of electrons and nuclei of individual donor atoms are attractive two level systems for encoding of quantum information. The coupling to the solid state environment is weak, so that decoherence times are long (hours for nuclear spins, and {approx}60 ms for electron spins of isolated P atoms in silicon …

Severe plastic deformation is observed within adiabatic shear bands in iron-carbon steels. These shear bands form under high strain rate conditions, in excess of 1000 s{sup -1}, and strains in the order 5 or greater are commonly observed. Studies on shear band formation in a ultrahigh carbon steel (1.3%C) are described in the pearlitic condition. A hardness of 11.5 GPa (4600 MPa) is obtained within the band. A mechanism is described to explain the high strength based on phase transformation to austenite from adiabatic heating resulting from severe deformation. Rapid re-transformation leads to an ultra-fine ferrite grain size containing carbon principally in the form of nanosize carbides. It is proposed that the same mechanism explains the ultrahigh strength of iron-carbon steels observed in ball-milling, ball drop tests and in severely deformed wires.

This report addresses the analysis and simulation of the structure of nanoparticles that undergo a surface-driven structural transformation.

Tunnels in jointed rocks can be subjected to severe dynamic loads because of rock bursts, coal bumps, and large earthquakes. A series of 3-dimensional simulations was performed, based on discrete element analysis to gain insights into the parameters that influence the response of such tunnels. The simulations looked at the effect of joint set orientation, the effect of joint spacing, the effect of pulse shape for a given displacement, and the influence of using rigid versus deformable blocks in the analyses. The results of this modeling were also compared to field evidence of dynamic tunnel failures. This comparison reinforced the notion that 3-dimensional discrete element analysis can capture very well the kinematics of structures in jointed rock under dynamic loading.

We find clusters and superclusters of galaxies using the Data Release 1 of the Sloan Digital Sky Survey. We determine the luminosity function of clusters and find that clusters in a high-density environment have a luminosity a factor of {approx}5 higher than in a low-density environment. We also study clusters and superclusters in numerical simulations. Simulated clusters in a high-density environment are also more massive than those in a low-density environment. Comparison of the density distribution at various epochs in simulations shows that in large low-density regions (voids) dynamical evolution is very slow and stops at an early epoch. In contrast, in large regions of higher density (superclusters) dynamical evolution starts early and continues until the present; here particles cluster early, and by merging of smaller groups very rich systems of galaxies form.

Most small wind turbines furl (yaw or tilt out of the wind) as a means of limiting power and rotor speeds in high winds. The Small Wind Research Turbine (SWRT) testing project was initiated in 2003 with the goal of better characterizing both small wind turbine loads (including thrust) and dynamic behavior, specifically as they relate to furling. The main purpose of the testing was to produce high-quality data sets for model development and validation and to help the wind industry further their understanding of small wind turbine behavior. Testing was conducted on a modified Bergey Excel 10-kW wind turbine. A special shaft sensor was designed to measure shaft loads including thrust, torque, and shaft bending. Analysis of 10-minute mean data showed a strong correlation between furling and center of thrust location, as calculated from the shaft-bending and thrust measurements. Data were collected for three different turbine configurations that included a change in the lateral furling offset and the blades. An analysis of inflow conditions indicated that organized atmospheric turbulence had some impact on furling.

With the publication of IEEE 1547-2003(TM) Standard for Interconnecting Distributed Resources With Electric Power Systems, the electric power industry has a need to develop tests and procedures to verify that interconnection equipment meets 1547 technical requirements. A new standard, IEEE P1547.1(TM), is being written to give detailed tests and procedures for confirming that equipment meets the interconnection requirements. The National Renewable Energy Laboratory has been validating test procedures being developed as part of IEEE P1547.1. As work progresses on the validation of those procedures, information and test reports are passed on to the working group of IEEE P1547.1 for future revisions.

Annihilation of extremely energetic cosmic neutrinos on the relic-neutrino background can give rise to absorption lines at energies corresponding to formation of the electroweak gauge boson Z{sup 0}. The positions of the absorption dips are set by the masses of the relic neutrinos. Suitably intense sources of extremely energetic (10{sup 21} - 10{sup 25}-eV) cosmic neutrinos might therefore enable the determination of the absolute neutrino masses and the flavor composition of the mass eigenstates. Several factors--other than neutrino mass and composition--distort the absorption lines, however. We analyze the influence of the time-evolution of the relic-neutrino density and the consequences of neutrino decay. We consider the sensitivity of the lineshape to the age and character of extremely energetic neutrino sources, and to the thermal history of the Universe, reflected in the expansion rate. We take into account Fermi motion arising from the thermal distribution of the relic-neutrino gas. We also note the implications of Dirac vs. Majorana relics, and briefly consider unconventional neutrino histories. We ask what kinds of external information would enhance the potential of cosmic-neutrino absorption spectroscopy, and estimate the sensitivity required to make the technique a reality.

The SAMGrid team is in the process of implementing a monitoring and information service, which fulfills several important roles in the operation of the SAMGrid system, and will replace the first generation of monitoring tools in the current deployments. The first generation tools are in general based on text log-files and represent solutions which are not scalable or maintainable. The roles of the monitoring and information service are: (1) providing diagnostics for troubleshooting the operation of SAMGrid services; (2) providing support for monitoring at the level of user jobs; (3) providing runtime support for local configuration and other information which currently must be stored centrally (thus moving the system toward greater autonomy for the SAMGrid station services, which include cache management and job management services); (4) providing intelligent collection of statistics in order to enable performance monitoring and tuning. The architecture of this service is quite flexible, permitting input from any instrumented SAMGrid application or service. It will allow multiple backend storage for archiving of (possibly) filtered monitoring events, as well as real time information displays and active notification service for alarm conditions. This service will be able to export, in a configurable manner, information to higher level Grid monitoring …

I report here a redesign of the CKM RICH velocity spectrometers for use in a 1/4 GHz unseparated beam adapted to the KTeV beam line and detector hall at Fermilab (P940). The redesigns reported here comprise modest modification to the original designs for CKM(E921) to accommodate the change in beam flux, momentum, and momentum bite of the primary beam. The ultimate performance of the velocity spectrometer systems, as quantified by the missing mass squared resolution for K{sup +} {yields} {pi}{sup +} x{sup 0}, remains largely unchanged from the original design.

The federal government strives to lead by example in energy and resource management and architectural design. This paper explores how public agencies are supporting that goal by using sustainable practices in the design and operation of their buildings. It presents some elements to consider in establishing a policy for sustainable design and a system for implementing that policy, including some of the most difficult implementation issues agencies have to face. The paper also highlights some of the strengths and weaknesses of federal, state, and local policies and practices governing the design of public buildings; two case studies provide examples. Different approaches are included to help agencies evaluate their effectiveness at various levels of government. And recommendations are made for agencies and others who are committed to sustainable design in both new construction and major renovations.

Results of the first measurement of {sup 3}P orbitally excited neutral D-meson states, D*{sub 2}{sup 0} and D{sub 1}{sup 0}, produced in hadron collisions at the Tevatron are presented. Using data from the displaced track trigger, CDF II collects a large sample of these states in decay modes D*{sup +} {pi}{sup -}, D{sup +} {pi}{sup -}. Masses and widths of both states have been measured with precision better than or comparable to that of the world average.