Novel Insights into the Diversity of Catabolic Metabolism from Ten Haloarchaeal Genomes (open access)

Novel Insights into the Diversity of Catabolic Metabolism from Ten Haloarchaeal Genomes

The extremely halophilic archaea are present worldwide in saline environments and have important biotechnological applications. Ten complete genomes of haloarchaea are now available, providing an opportunity for comparative analysis. We report here the comparative analysis of five newly sequenced haloarchaeal genomes with five previously published ones. Whole genome trees based on protein sequences provide strong support for deep relationships between the ten organisms. Using a soft clustering approach, we identified 887 protein clusters present in all halophiles. Of these core clusters, 112 are not found in any other archaea and therefore constitute the haloarchaeal signature. Four of the halophiles were isolated from water, and four were isolated from soil or sediment. Although there are few habitat-specific clusters, the soil/sediment halophiles tend to have greater capacity for polysaccharide degradation, siderophore synthesis, and cell wall modification. Halorhabdus utahensis and Haloterrigena turkmenica encode over forty glycosyl hydrolases each, and may be capable of breaking down naturally occurring complex carbohydrates. H. utahensis is specialized for growth on carbohydrates and has few amino acid degradation pathways. It uses the non-oxidative pentose phosphate pathway instead of the oxidative pathway, giving it more flexibility in the metabolism of pentoses. These new genomes expand our understanding of haloarchaeal …
Date: May 3, 2011
Creator: Anderson, Iain; Scheuner, Carmen; Goker, Markus; Mavromatis, Kostas; Hooper, Sean D.; Porat, Iris et al.
System: The UNT Digital Library
Mismatch Oscillations in High Current Accelerators (open access)

Mismatch Oscillations in High Current Accelerators

When planning the design of high-current FODO transport for accelerators, it is useful to have simple, accurate tools for calculating quantities such as the phase advances {sigma}{sub 0} and !given the lattice and beam parameters. Along with the KV beam model, the smooth approximation is often used. It is simple but not very accurate in many cases. Although Struckmeier and Reiser [1] showed that the stable oscillation frequencies of mismatched beams could be obtained accurately, they actually used a hybrid approach where {sigma}{sub 0} and {sigma} were already known precisely. When starting instead with basic quantities such as quadrupole dimensions, field strength, beam line charge density and emittance, the smooth approximation gives substantial errors. Here we derive a simple modification of the smooth approximation formula that improves the accuracy of the predicted frequencies by a factor of five at {sigma}{sub 0} = 83{sup o}.
Date: May 3, 2005
Creator: Anderson, O. A.
System: The UNT Digital Library
A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid (open access)

A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.
Date: May 3, 2010
Creator: Arceo, Elena; Ellman, Jonathan & Bergman, Robert
System: The UNT Digital Library
Searches for Astrophysical and Cosmological Axions (open access)

Searches for Astrophysical and Cosmological Axions

The axion remains, after nearly 30 years, the most compelling and elegant solution to the strong-CP problem, i.e. why this symmetry is protected in QCD in spite of CP violation elsewhere. The axion is expected to be extremely light, and possess extraordinarily feeble couplings to matter and radiation. Because of its small couplings, the axion has defied experimental confirmation and is unlikely to be discovered in conventional laboratory experiments (i.e. production-detection). Nevertheless, a sufficiently light axion would have been produced abundantly in the Big Bang and is an excellent candidate for the dark matter of the Universe. Through the axion's two-photon coupling, implying axion-photon mixing in an external electromagnetic field, galactic halo axions may be feasibly detected by their resonant conversion to RF photons in a microwave cavity permeated by magnetic field with current technology. Over the past decade experiments have already set interesting limits in mass and coupling; upgrades in progress to photon detection schemes at or below the standard quantum limit will soon enable definitive searches. Similarly, axions produced in the solar burning core might be detectable by their conversion to x-rays in a magnetic helioscope. Indeed current published limits already equal the best bounds on axion-photon coupling …
Date: May 3, 2006
Creator: Asztalos, S J; Rosenberg, L J; van Bibber, K; Sikivie, P & Zioutas, K
System: The UNT Digital Library
Heating of nuclear matter and multifragmentation : antiprotons vs. pions. (open access)

Heating of nuclear matter and multifragmentation : antiprotons vs. pions.

Heating of nuclear matter with 8 GeV/c {bar p} and {pi}{sup {minus}} beams has been investigated in an experiment conducted at BNL AGS accelerator. All charged particles from protons to Z {approx_equal} 16 were detected using the Indiana Silicon Sphere 4{pi} array. Significant enhancement of energy deposition in high multiplicity events is observed for antiprotons compared to other hadron beams. The experimental trends are qualitatively consistent with predictions from an intranuclear cascade code.
Date: May 3, 1999
Creator: Back, B.; Beaulieu, L.; Breuer, H.; Gushue, S.; Hsi, W.-C.; Korteling, R. G. et al.
System: The UNT Digital Library
Heating {sup 197}Au nuclei with 8 GeV antiproton and {pi}- beams. (open access)

Heating {sup 197}Au nuclei with 8 GeV antiproton and {pi}- beams.

This contribution stresses results recently obtained from experiment E900 performed at the Brookhaven AGS accelerator with 8 GeV/c antiproton and negative pion beams using the Indiana Silicon Sphere detector array. An investigation of the reaction mechanism is presented, along with source characteristics deduced from a two-component fit to the spectra. An enhancement of deposition energy with the antiproton beam with respect to the pion beam is observed. The results are qualitatively consistent with predictions of an intranuclear cascade code.
Date: May 3, 1999
Creator: Back, B.; Beaulieu, L.; Breuer, H.; Gushue, S.; Hsi, W.-C.; Korteling, R. G. et al.
System: The UNT Digital Library
Isolating the thermal degree of freedom in nuclear multifragmentation. (open access)

Isolating the thermal degree of freedom in nuclear multifragmentation.

Multifragmentation studies induced by GeV light-ion beams permit investigation of the influence of intrinsic thermal properties of hot nuclear matter, with minimal interference from the compression/decompression cycle and rotational instabilities. We summarize recent results obtained with {sup 3}He, proton and pion beams up to 15 GeV/c and present the initial results from a recent experiment with 8 GeV/c antiproton and pion beams. The results are compared with INC simulations coupled to EES and SMM models and the caloric curve for the {sup 3}He data will also be discussed.
Date: May 3, 1999
Creator: Back, B.; Beaulieu, L.; Breuer, H.; Gushue, S.; Hsi, W.-C.; Korteling, R. G. et al.
System: The UNT Digital Library
Influence of Rapid Thermal Ramp Rate on Phase Transformation of Titanium Silicides (open access)

Influence of Rapid Thermal Ramp Rate on Phase Transformation of Titanium Silicides

ULSI technology requires low resistance, stable silicides formed on small geometry lines. Titanium disilicide (TiSiz), which is the most widely used silicide for ULSI applications, exists in two crystallographic phases: the high resistance, metastable C49 phase and the low resistance, stable C54 phase. The major issue with TiSiz is the increasing thermal budget required to transform the C49 phase into the low resistance C54 phase as linewiths decrease below 0.25 pm. Annealing above 900"C to obtain this transformation often results in thermal degradation, so it is desirable to reduce the transformation temperature. The transformation temperature has been shown to be a fi.mction of many factors including microstructure, grain size, and impurities. In this paper we report an investig+ion of rapid thermal silicidation of titanium films (250, 400, and 600 A) on single crystalline silicon at temperatures from 300 to 1000"C. The ramp rates for these experiments are 5, 30, 70, and 200oC/s. The transformation temperature decreases as the ramp rate increases and as the initial film thickness increases. Scanning electron microscopy (SEM) is used to analyze the resultant film microstructure. The ramp rate influence on Ti silicidation is also investigated on polycrystalline Si lines with widths ranging from 0.27 to …
Date: May 3, 1999
Creator: Bailey, Glenn; Hu, Yao, Zhi; Smith, Paul Martin; Tay, Sing Pin; Thakur, Randhir & Yang, Jiting
System: The UNT Digital Library
High temperature stability multilayers for EUV condenser optics (open access)

High temperature stability multilayers for EUV condenser optics

We investigate the thermal stability of Mo/SiC multilayer coatings at elevated temperatures. Transmission electron microscopy and x-ray diffraction studies show that upon annealing a thermally-induced structural relaxation occurs that transforms the polycrystalline Mo and amorphous SiC layers in as-deposited multilayers into amorphous Mo-Si-C alloy and crystalline SiC, respectively. After this relaxation process is complete the multilayer is stable at temperatures up to 400 C.
Date: May 3, 2005
Creator: Bajt, S & Stearns, D G
System: The UNT Digital Library
Scale up issues involved with the ceramic waste form : ceramic-container interactions and ceramic cracking quantification. (open access)

Scale up issues involved with the ceramic waste form : ceramic-container interactions and ceramic cracking quantification.

Argonne National Laboratory is developing a process for the conditioning of spent nuclear fuel to prepare the material for final disposal. Two waste streams will result from the treatment process, a stainless steel based form and a ceramic based form. The ceramic waste form will be enclosed in a stainless steel container. In order to assess the performance of the ceramic waste form in a repository two factors must be examined, the surface area increases caused by waste form cracking and any ceramic/canister interactions that may release toxic material. The results indicate that the surface area increases are less than the High Level Waste glass and any toxic releases are below regulatory limits.
Date: May 3, 1999
Creator: Bateman, K. J.; DiSanto, T.; Goff, K. M.; Johnson, S. G.; O'Holleran, T. & Riley, W. P., Jr.
System: The UNT Digital Library
Measurement of the beam longitudinal profile in a storage ring bynon-linear laser mixing (open access)

Measurement of the beam longitudinal profile in a storage ring bynon-linear laser mixing

We report on the development of a new technique for the measurement of the longitudinal beam profile in storage rings. This technique, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store, and display the required information. The available choices of laser repetition frequency, pulse width, and phase modulation give a wide range of options for matching the bunch configuration of a particular storage ring. Besides the dynamic measurement of the longitudinal profile of each bunch, the instrument can monitor the evolution of the bunch tails, the presence of untrapped particles and their diffusion into nominally empty RF buckets (''ghostbunches'').
Date: May 3, 2004
Creator: Beche, J.-F.; Byrd, J.; De Santis, S.; Denes, P.; Placidi, M.; Turner, W. et al.
System: The UNT Digital Library
Development of an abort gap monitor for high-energy proton rings (open access)

Development of an abort gap monitor for high-energy proton rings

The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the ''abort gap'' and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitor based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider
Date: May 3, 2004
Creator: Beche, Jean-Francois; Byrd, John; De Santis, Stefano; Denes, Peter; Placidi, Massimo; Turner, William et al.
System: The UNT Digital Library
Improvement of Photosynthetic Efficiency Through Reduction of Chlorophyll Antenna Size (open access)

Improvement of Photosynthetic Efficiency Through Reduction of Chlorophyll Antenna Size

We have previously presented a graphical illustration of a strategy to improve photosynthetic conversion efficiencies by a reduction of the antenna size in photosynthetic reaction centers. During the current reporting period, we have made progress in demonstrating the conceptual correctness of this idea. Light-saturation studies for CO, in air were performed with an antenna-deficient mutant of Chlamydomonas (DS521) and the wild type (DES15). The light-saturated rate for CO(2), assimilation in mutant DS521 was about two times higher (187 Mu-mol.h(-1).mg chl(-1)) than that of the wild type, DES15 (95 Mu-mol.h(-1).mg chl(-1). Significantly, a partial linearization of the light-saturation curve was also observed. The light intensities that give half-saturation of the photosynthetic rate were 276 and 152 Mu-E.m(-2).s(-1) in DS521 and DES15, respectively. These results confirmed that DS521 has a smaller chlorophyll antenna size and demonstrated that the reduction of antenna size can indeed improve the overall efficiency of photon utilization. Corresponding experiments were also performed with CO(2), in helium. Under this anaerobic condition, no photoinhibition was observed, even at elevated light intensities. Photoinhibition occurs under aerobic conditions. The antenna-deficient mutant DS521 can also provide significant resistance to photoinhibition, in addition to the improvement in the overall efficiency in CO(2), fixation.
Date: May 3, 1999
Creator: Blankinship, S.L.; Greenbaum, E.; Lee, J.W. & Mets, L.
System: The UNT Digital Library
Saturating interactions in /sup 4/He with density dependence (open access)

Saturating interactions in /sup 4/He with density dependence

With the advent of larger and faster computers, as well as modern shell model codes, nuclear structure calculations for the light nuclei (A<16) which include full 2/bar h/..omega.. model spaces are quite feasible. However, there can be serious problems in the mixing of 2/bar h/..omega.. and higher excitations into the low-lying spectra if the effective interaction is non-saturating. Furthermore, effective interactions which are both saturating and density dependent have not generally been used in previous nuclear structure calculations. Therefore, we have undertaken studies of /sup 4/He using two-body potential interactions which incorporate both saturation and density-dependence. Encouraging initial results in remedying the mixing of 0 and 2/bar h/..omega.. excitations have been obtained. We have also considered the effects of our interaction on the /sup 4/He compressibility and the centroid of the breathing mode strength. First indications are that a saturating effective interaction, with a short-range density dependent part and a long-range density independent part, comes close to matching crude predictions for the compressibility of /sup 4/He. 11 refs., 6 tabs.
Date: May 3, 1989
Creator: Bloom, S.D.; Resler, D.A. & Moszkowski, S.A.
System: The UNT Digital Library
Electronic structure and f-orbital occupancy in Yb-substituted CeCoIn5 (open access)

Electronic structure and f-orbital occupancy in Yb-substituted CeCoIn5

The local structure and 4f orbital occupancy have been investigated in Ce{sub 1−x}Yb{sub x}CoIn{sub 5} via Yb L{sub III}-edge extended x-ray absorption fine structure (EXAFS), Ce and Yb L{sub III}-edge x-ray absorption near-edge structure (XANES), and angle-resolved photoemission spectroscopy (ARPES) measurements. Yb(III) (4f{sup 13}) is the hole analog of Ce(III) (4f{sup 1}). Yb is found to be strongly intermediate-valent in Ce{sub 1−x}Yb{sub x}CoIn{sub 5} throughout the entire doping range, including pure YbCoIn{sub 5}, with an f-hole occupancy for Yb of n{sub f} ≃ 0.3 (i.e. Yb{sup 2.3+}), independent of Yb concentration and independent of temperature down to T = 20 K. In contrast, the f-electron orbital occupancy for Ce remains close to 1 for all Yb concentrations, suggesting that there is no mutual influence on n{sub f} between neighboring Ce and Yb sites. Likewise, ARPES measurements at 12 K have found that the electronic structure along {Gamma} − X is not sensitive to the Yb substitution, suggesting that the Kondo hybridization of Ce f electrons with the conduction band is not affected by the presence of Yb impurities in the lattice. The emerging picture is that in Ce{sub 1−x}Yb{sub x}CoIn{sub 5} there are two networks, interlaced but independent, that couple …
Date: May 3, 2011
Creator: Booth, C. H.; Durakiewicz, T.; Capan, C.; Hurt, D.; Bianchi, A. D.; Joyce, J.J. et al.
System: The UNT Digital Library
Portable data acquisition system (open access)

Portable data acquisition system

Lawrence Livermore National Laboratory (LLNL) has developed a Portable Data Acquisition (DAQ) System that is basically a laboratory-scale of Program Logic Control (PLC). This DAQ system can obtain signals from numerous sensors (e.g., pH, level, pressure, flow meters), open and close valves, and turn on and off pumps. The data can then be saved on a spreadsheet or displayed as a graph/indicator in real-time on a computer screen. The whole DAQ system was designed to be portable so that it could sit on a bench top during laboratory-scale treatability studies, or moved out into the field during larger studies. This DAQ system is also fairly simple to use. All that is required is some working knowledge of LabVIEW 4.1, and how to properly wire the process equipment. The DAQ system has been used during treatability studies on cesium precipitation, controlled hydrolysis of water- reactive wastes, and other waste treatment studies that enable LLNL to comply with the Federal Facility Compliance Act (FFCAct). Improved data acquisition allows the study to be better monitored, and therefore better controlled, and can be used to determine the results of the treatment study more effectively. This also contributes to the design of larger treatment processes.
Date: May 3, 1999
Creator: Bowers, J & Rogers, H
System: The UNT Digital Library
Exotic Effects at the Charm Threshold and Other Novel Physics Topics at JLab-12 GeV (open access)

Exotic Effects at the Charm Threshold and Other Novel Physics Topics at JLab-12 GeV

I briefly survey a number of novel hadron physics topics which can be investigated with the 12 GeV upgrade at J-Lab. The topics include new the formation of exotic heavy quark resonances accessible above the charm threshold, intrinsic charm and strangeness phenomena, the exclusive Sivers effect, hidden-color Fock states of nuclei, local two-photon interactions in deeply virtual Compton scattering, and non-universal antishadowing.
Date: May 3, 2012
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
A novel method for diagnosing the growth of subresolution-scale perturbations (open access)

A novel method for diagnosing the growth of subresolution-scale perturbations

We have demonstrated a technique for diagnosing the growth of subresolution-scale perturbations by the appearance of longer-wavelength, coupled modes once the growth has proceeded into the nonlinear regime. Comparison of the growth rate of this larger scale feature with numerical simulations can then be used to infer the growth rates of the initial perturbations. This experiment was conceived as an analog of large-scale computer simulations where the large eddy approximation is applied. There a subgrid-scale model is used to represent the effects of small scales on large-scale motion, which is directly numerically simulated.
Date: May 3, 1996
Creator: Budil, K. S.; Remington, B. A. & Perry, T. S.
System: The UNT Digital Library
Gated Microchannel Plate Photomultiplier For Longitudinal BeamDiagnostics (open access)

Gated Microchannel Plate Photomultiplier For Longitudinal BeamDiagnostics

A gated microchannel plate photomultiplier can be used as aneffective tool for measuring the longitudinal distribution of particlesaround most electron and high-energy proton rings. The broad availablewavelength range,low noise, and high sensitivity allow using such adevice for measuring the emitted synchrotron radiation and to extract thebeam intensity. The fast gate rise time can be used to reject strongsignals coming from filled RF buckets and avoid saturation of thephotocathode so that it is possible to monitor, with a high degree ofresolution, gaps in the machine fill and growth of parasitic bunches. Therugged characteristics of the device and its simplicity of use make itideal for all those applications where more complex and expensiveinstrumentation is not absolutely necessary. We present the experimentalresults obtained at the Advanced Light Source and on the Tevatron usingan Hamamatsu R5916U-50 series model.
Date: May 3, 2006
Creator: Byrd, John M.; De Santis, Stefano & Thurman-Keup, Randy
System: The UNT Digital Library
Implementing Management Systems-Based Assessments (open access)

Implementing Management Systems-Based Assessments

A management system approach for evaluating environment, safety, health, and quality is in use at Sandia National Laboratories (SNL). Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000. As a multi-program national laboratory, SNL has many diverse operations including research, engineering development and applications, production, and central services supporting all activities and operations. Basic research examples include fusion power generation, nuclear reactor experiments, and investigation of combustion processes. Engineering development examples are design, testing, and prototype developments of micro-mechanical systems for safe'~arding computer systems, air bags for automobiles, satellite systems, design of transportation systems for nuclear materials, and systems for use in medical applications such as diagnostics and surgery. Production operations include manufacture of instrumented detection devices, radioisotopes, and replacement parts for previously produced engineered systems. Support services include facilities engineering, construction, and site management, site security, packaging and transportation of hazardous materials wastes, ES&H functional programs to establish requirements and guidance to comply with federal, state, local, and contractual requirements and work safety. In this diverse environment, unlike more traditional single function business units, an integrated consistent management system is not typical. Instead, each type …
Date: May 3, 1999
Creator: Campisi, John A. & Reese, Robert T.
System: The UNT Digital Library
Status of the new muon (g - 2) experiment. (open access)

Status of the new muon (g - 2) experiment.

The new muon (g - 2) experiment is now fully operational The goal of the experiment is to obtain a relative error on (g - 2) of {+-}O.35 ppm to measure the electroweak contribution for the first time, and to observe, or place stringent limits on physics beyond the standard model which can contribute to (g - 2). A brief status report is presented.
Date: May 3, 1999
Creator: Carey, R. M.; Earle, W.; Efstathiadis, E.; Hare, M. F.; Collaboration, MUON (g - 2); Nodulman, L. et al.
System: The UNT Digital Library
Aqueous biphasic systems for metal separations : a microcalorimetric analysis of polymer/salt interactions. (open access)

Aqueous biphasic systems for metal separations : a microcalorimetric analysis of polymer/salt interactions.

Certain radionuclide ions (e.g., TcO{sub 4}{sup 16}) exhibit unusually strong Affinities toward the polymer-rich phase in aqueous biphase systems generated by combinations of salt solutions with polymers such as poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Thus, aqueous polymer phases could potentially be used to selectively extract these ions during pretreatment of radioactive tank wastes at Hanford. To help develop a fundamental understanding of the interactions between various ions and polymers in aqueous solution, interaction enthalpies between sodium perrhenate and a random copolymer of PEG and PPG (UCON-50) were measured by microcalorimetric titration. An entropy compensation effect was observed in this system in which changes in enthalpic interactions were balanced by entropy changes such that the interaction free energy remained constant and approximately equal to zero.
Date: May 3, 1999
Creator: Chaiko, D. J.; Hatton, T. A. & Zaslavsky, B.
System: The UNT Digital Library
Interim Results from Alternative Fuel Truck Evaluation Project (open access)

Interim Results from Alternative Fuel Truck Evaluation Project

The objective of this project, which is supported by the U.S. Department of Energy (DOE) through the National Renewable Energy Laboratory (NREL), is to provide a comprehensive comparison of heavy-duty trucks operating on alternative fuels and diesel fuel. Data collection from up to eight sites is planned. Currently, the project has four sites: Raley's in Sacramento, CA (Kenworth, Cummins LlO-300G, liquefied natural gas - LNG); Pima Gro Systems, Inc. in Fontana, CA (White/GMC, Caterpillar 31768 Dual-Fuel, compressed natural gas - CNG); Waste Management in Washington, PA (Mack, Mack E7G, LNG); and United Parcel Service in Hartford, CT (Freightliner Custom Chassis, Cummins B5.9G, CNG). This paper summarizes current data collection and evaluation results from this project.
Date: May 3, 1999
Creator: Chandler, Kevin L.; Norton, Paul & Clark, Nigel
System: The UNT Digital Library
W, Z + jets at Tevatron (open access)

W, Z + jets at Tevatron

We report the production jet cross-sections and properties in W and Z events using data from collisions with {radical}s = 1800 GeV at Fermilab Tevatron. Observed distributions in general agree with predictions of leading order QCD matrix element calculations with added gluon radiations and simulated parton fragmentations; however, some limitations of LO QCD predictions are also observed. The cross-section ratio of W + {>=} 1 jet events to inclusive W events is reported and compared with next-to-the-leading order QCD expectations. Good agreement between data and theory is seen. The color coherence effects are also observed in W+ jets events.
Date: May 3, 1999
Creator: Chang, Paoti
System: The UNT Digital Library