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Global Analysis of Heat Shock Response in Desulfovibrio vulgaris Hildenborough. (open access)

Global Analysis of Heat Shock Response in Desulfovibrio vulgaris Hildenborough.

Desulfovibrio vulgaris Hildenborough belongs to a class ofsulfate-reducing bacteria (SRB) and is found ubiquitously in nature.Given the importance of SRB-mediated reduction for bioremediation ofmetal ion contaminants, ongoing research on D. vulgaris has been in thedirection of elucidating regulatory mechanisms for this organism under avariety of stress conditions. This work presents a global view of thisorganism's response to elevated growth temperature using whole-celltranscriptomics and proteomics tools. Transcriptional response (1.7-foldchange or greater; Z>1.5) ranged from 1,135 genes at 15 min to 1,463genes at 120 min for a temperature up-shift of 13oC from a growthtemperature of 37oC for this organism and suggested both direct andindirect modes of heat sensing. Clusters of orthologous group categoriesthat were significantly affected included posttranslationalmodifications; protein turnover and chaperones (up-regulated); energyproduction and conversion (down-regulated), nucleotide transport,metabolism (down-regulated), and translation; ribosomal structure; andbiogenesis (down-regulated). Analysis of the genome sequence revealed thepresence of features of both negative and positive regulation whichincluded the CIRCE element and promoter sequences corresponding to thealternate sigma factors ?32 and ?54. While mechanisms of heat shockcontrol for some genes appeared to coincide with those established forEscherichia coli and Bacillus subtilis, the presence of unique controlschemes for several other genes was also evident. Analysis of proteinexpression levels using …
Date: September 16, 2005
Creator: Chhabra, S. R.; He, Q.; Huang, K. H.; Gaucher, S. P.; Alm, E. J.; He, Z. et al.
System: The UNT Digital Library
Determining important parameters related to cyanobacterial alkaloid toxin exposure (open access)

Determining important parameters related to cyanobacterial alkaloid toxin exposure

Science-based decision making required robust and high-fidelity mechanistic data about the system dynamics and impacts of system changes. Alkaloid cyanotoxins have the characteristics to warrant consideration for their potential threat. Since insufficient information is available to construct a systems model for the alkaloid cyanotoxins, saxitoxins, anatoxins, and anatoxin-a(S), an accurate assessments of these toxins as a potential threat for use for intentional contamination is not possible. Alkaloid cyanotoxin research that contributed to such a model has numerous areas of overlap for natural and intentional health effects issues that generates dual improvements to the state of the science. The use of sensitivity analyses of systems models can identify parameters that, when determined, result in the greatest impact to the overall system and may help to direct the most efficient use of research funding. This type of modeling-assisted experimentation may allow rapid progress for overall system understanding compared to observational or disciplinary research agendas. Assessment and management of risk from intentional contamination can be performed with greater confidence when mechanisms are known and the relationships between different components are validated. This level of understanding allows high-fidelity assessments that do not hamper legitimate possession of these toxins for research purposes, while preventing intentional …
Date: September 16, 2005
Creator: Love, A H
System: The UNT Digital Library
Initiation of Heated PBX-9501 Explosive When Exposed to Dynamic Loading (open access)

Initiation of Heated PBX-9501 Explosive When Exposed to Dynamic Loading

Shock initiation experiments on the heated PBX9501 explosive (95% HMX, 2.5% estane, and 2.5% nitro-plasticizer by weight) were performed at temperatures 150 C and 180 C to obtain in-situ pressure gauge data. A 101 mm diameter propellant driven gas gun was utilized to initiate the PBX9501 explosive and manganin piezo-resistive pressure gauge packages were placed between sample slices to measure time resolved local pressure histories. The run-distance-to-detonation points on the Pop-plot for these experiments showed the sensitivity of the heated material to shock loading. This work shows that heated PBX-9501 is more shock sensitive than it is at ambient conditions. Proper Ignition and Growth modeling parameters were obtained to fit the experimental data. This parameter set will allow accurate code predictions to be calculated for safety scenarios involving PBX9501 explosives at temperatures close to those at which experiments were performed.
Date: August 16, 2005
Creator: Urtiew, P A; Vandersall, K S; Tarver, C M & Garcia, F
System: The UNT Digital Library
The Community Climate System Model Project from an Interagency Perspective (open access)

The Community Climate System Model Project from an Interagency Perspective

In 2007, the Intergovernmental Panel on Climate Change (IPCC) will publish its Fourth Assessment Report of the Scientific Basis of Climate Change (AR4). A significant portion of the AR4 will be the analysis of coupled general circulation model (GCM) simulations of the climate of the past century as well as scenarios of future climates under prescribed emission scenarios. Modeling groups worldwide have contributed to AR4, including three from the U.S., the Community Climate System Model (CCSM) project, the National Aeronautics and Space Administration (NASA) Goddard Institute for Space Sciences, and the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL). This collection of model results is providing a wealth of new information that will be used to examine the state of climate science, the potential impacts from climate changes, and the policy consequences that they imply. Our focus here is on the CCSM project. Although it is centered at the National Center for Atmospheric Research (NCAR), the CCSM version 3 (CCSM3) was designed, developed, and applied in a uniquely distributed fashion with participation by many institutions. This model has produced some of the most scientifically complete and highest resolution simulations of climate change to date, thanks to the …
Date: June 16, 2005
Creator: Bader, D C; Bamzai, A; Fein, J; Patrinos, A & Leinen, M
System: The UNT Digital Library
Symmetry reduction of (delta)-plutonium: an electronic-structure effect (open access)

Symmetry reduction of (delta)-plutonium: an electronic-structure effect

Using first-principles density-functional theory calculations, we show that the anomalously large anisotropy of {sigma}-plutonium is a consequence of greatly varying bond-strengths between the 12 nearest neighbors. Employing the calculated bond strengths, we expand the tenants of classical crystallography by incorporating anisotropy of chemical bonds, which yields a structure with the monoclinic space group Cm for {delta}-plutonium rather than face-centered cubic Fm{bar 3}m. The reduced space group for {delta}-plutonium enlightens why the ground state of the metal is monoclinic, why distortions of the metal are viable, and has considerable implications for the behavior of the material as it ages. These results illustrate how an expansion of classical crystallography that accounts for anisotropic electronic structure can explain complicated materials in a novel way.
Date: November 16, 2005
Creator: Moore, K; Soderlind, P; Schwartz, A & Laughlin, D
System: The UNT Digital Library
Unraveling the Fanconi anaemia-DNA repair connection through DNA helicase and translocase activities (open access)

Unraveling the Fanconi anaemia-DNA repair connection through DNA helicase and translocase activities

How the Fanconi anaemia (FA) chromosome stability pathway functions to cope with interstrand crosslinks and other DNA lesions has been elusive, even after FANCD1 proved to be BRCA2, a partner of Rad51 in homologous recombination. The identification and characterization of two new Fanconi proteins having helicase motifs, FANCM and FANCJ/BRIP1/BACH1, implicates the FANC nuclear core complex as a participant in recognizing or processing damaged DNA, and the BRIP1 helicase as acting independently of this complex.
Date: August 16, 2005
Creator: Thompson, L H
System: The UNT Digital Library
Correlation between Strand Stability and Magnet Performance (open access)

Correlation between Strand Stability and Magnet Performance

Magnet programs at BNL, LBNL and FNAL have observed instabilities in high J{sub c} Nb{sub 3}Sn strands and magnets made from these strands. This paper correlates the strand stability determined from a short sample-strand test to the observed magnet performance. It has been observed that strands that carry high currents at high fields (greater than 10T) cannot sustain these same currents at low fields (1-3T) when the sample current is fixed and the magnetic field is ramped. This suggests that the present generation of strand is susceptible to flux jumps (FJ). To prevent flux jumps from limiting stand performance, one must accommodate the energy released during a flux jump. To better understand FJ this work has focused on wire with a given sub-element diameter and shows that one can significantly improve stability by increasing the copper conductivity (higher residual resistivity ratio, RRR, of the Cu). This increased stability significantly improves the conductor performance and permits it to carry more current.
Date: April 16, 2005
Creator: Dietderich, Daniel R.; Bartlett, Scott E.; Caspi, Shlomo; Ferracin, Paolo; G ourlay, Stephen A.; Higley, Hugh C. et al.
System: The UNT Digital Library
High Current Energy Recovery Linac at Bnl. (open access)

High Current Energy Recovery Linac at Bnl.

We present the design and parameters of an energy recovery linac (ERL) facility, which is under construction in the Collider-Accelerator Department at BNL. This R&D facility has the goal of demonstrating CW operation of an ERL with an average beam current in the range of 0.1-1 ampere and with very high efficiency of energy recovery. The possibility of a future upgrade to a two-pass ERL is also being considered. The heart of the facility is a 5-cell 703.75 MHz super-conducting RF linac with strong Higher Order Mode (HOM) damping. The flexible lattice of the ERL provides a test-bed for exploring issues of transverse and longitudinal instabilities and diagnostics of intense CW electron beams. This ERL is also perfectly suited for a far-IR FEL. We present the status and plans for construction and commissioning of this facility.
Date: May 16, 2005
Creator: Litvinenko, V. N.; Ben-Zvi, Ilan; Barton, D. S. & Al., Et
System: The UNT Digital Library
Extremely High Currect, High-Brightness Energy Recovery Linac. (open access)

Extremely High Currect, High-Brightness Energy Recovery Linac.

Next generation ERL light-sources, high-energy electron coolers, high-power Free-Electron Lasers, powerful Compton X-ray sources and many other accelerators were made possible by the emerging technology of high-power, high-brightness electron beams. In order to get the anticipated performance level of ampere-class currents, many technological barriers are yet to be broken. BNL's Collider-Accelerator Department is pursuing some of these technologies for its electron cooling of RHIC application, as well as a possible future electron-hadron collider. We will describe work on CW, high-current and high-brightness electron beams. This will include a description of a superconducting, laser-photocathode RF gun and an accelerator cavity capable of producing low emittance (about 1 micron rms normalized) one nano-Coulomb bunches at currents of the order of one ampere average.
Date: May 16, 2005
Creator: Ben-Zvi, Ilan; Barton, D.; Beavis, D.; Blaskiewicz, M. & AL., ET
System: The UNT Digital Library
Luminescence Beam Profile Monitor for the RHIC Polarized Hydrogen Jet Polarimeter. (open access)

Luminescence Beam Profile Monitor for the RHIC Polarized Hydrogen Jet Polarimeter.

A new polarized hydrogen jet target was used to provide improved beam polarization measurements during the second polarized proton m in the Relativistic Heavy Ion Collider (RHIC). The luminescence produced by beam-hydrogen excitations was also used to test the feasibility of a new beam profile monitor for RFPIC based on the detection of the emitted light. Lenses, a view-port and a sensitive CCD camera were added to the system to record the optical signals from the interaction chamber. The first very promising results are reported here. The same system with an additional optical spectrometer or optical filter system may be used in the future to detect impurities in the jet, such as oxygen molecules, which affect the accuracy of the polarization measurements.
Date: May 16, 2005
Creator: Luciano, N.; Nass, A.; Makdisi, Y.; Thieberger, P.; Trbojevic, D. & Zelenski, A.
System: The UNT Digital Library
Performance Limitations in High-Energy Ion Colliders (open access)

Performance Limitations in High-Energy Ion Colliders

High-energy ion colliders (hadron colliders operating with ions other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams limits are set by space charge, charge exchange, and intrabeam scattering effects. The latter leads to luminosity lifetimes of only a few hours for intense heavy ions beams. Currently, the Relativistic Heavy Ion Collider (RHIC) at BNL is the only operating high-energy ion collider. Later this decade the Large Hadron Collider (LHC), under construction at CERN, will also run with heavy ions.
Date: May 16, 2005
Creator: Fischer, W.
System: The UNT Digital Library
BEAM-BEAM SIMULATIONS FOR THE ERHIC ELECTRON RING. (open access)

BEAM-BEAM SIMULATIONS FOR THE ERHIC ELECTRON RING.

To study collisions between polarized electrons and heavy ions or polarized protons at high energy, adding a 10 GeV electron storage ring to the existing RHIC facility is currently under consideration. To achieve high luminosities of several 10{sup 33} cm{sup -2} sec{sup -1} range, a vertical beam-beam tuneshift parameter of {zeta}{sub y} = 0.08 is required for the electron beam. Simulation studies are being performed to study the feasibility of this high tuneshift parameter and explore the potential for even higher tuneshifts. Recent results of these studies are presented.
Date: May 16, 2005
Creator: Montag, C.
System: The UNT Digital Library
Beam Loss Estimates and Control for the BNL Neutrino Facility. (open access)

Beam Loss Estimates and Control for the BNL Neutrino Facility.

The requirement for low beam loss is very important both to protect the beam component, and to make the hands-on maintenance possible. In this report, the design considerations to achieving high intensity and low loss will be presented. We start by specifying the beam loss limit at every physical process followed by the proper design and parameters for realizing the required goals. The process considered in this paper include the emittance growth in the linac, the H{sup -} injection, the transition crossing, the coherent instabilities and the extraction losses.
Date: May 16, 2005
Creator: Weng, W. T.; Lee, Y. Y.; Raparia, D.; Tsoupas, N.; Beebe-Wang, J.; Wei, J. et al.
System: The UNT Digital Library
Pulsed Power Applications in High Intensity Proton Rings. (open access)

Pulsed Power Applications in High Intensity Proton Rings.

Pulsed power technology has been applied in particle accelerators and storage rings for over four decades. It is most commonly used in injection, extraction, beam manipulation, source, and focusing systems. These systems belong to the class of repetitive pulsed power. In this presentation, we review and discuss the history, present status, and future challenge of pulsed power applications in high intensity proton accelerators and storage rings.
Date: May 16, 2005
Creator: Zhang, S. Y.; Sandberg, J. & Al., Et
System: The UNT Digital Library
Optimization of the Phase Advance Between Rhic Interaction Points. (open access)

Optimization of the Phase Advance Between Rhic Interaction Points.

The authors consider a scenario of having two identical Interaction Points (IPs) in the Relativistic Heavy Ion Collider (RHIC). The strengths of beam-beam resonances strongly depend on the phase advance between these two IPs and therefore certain phase advances could improve beam life-time and luminosity. The authors compute the dynamic aperture (DA) as function of the phase advance between these IPs to find the optimum settings.The beam-beam interaction is treated in the weak-strong approximation and a non-linear model of the lattice is used. For the current RHIC proton working point (0.69.0.685) [1] the design lattice is found to have the optimum phase advance. However this is not the case for other working points.
Date: May 16, 2005
Creator: Tomas, R. & Fischer, W.
System: The UNT Digital Library
Electron Cloud at Collimator and Injection Region of the Spallation Neutron Source Accumulator Ring. (open access)

Electron Cloud at Collimator and Injection Region of the Spallation Neutron Source Accumulator Ring.

The beam loss along the Spallation Neutron Source's accumulator ring is mainly located at the collimator region and injection region. This paper studied the electron cloud build-up at these two regions with the three-dimension program CLOUDLAND.
Date: May 16, 2005
Creator: Wang, L.; Hseuh, H. C.; Lee, Y. Y.; Raparia, D.; Wei, J. & Cousineau, S.
System: The UNT Digital Library
HELIUM FLOW INDUCED ORBIT JITTER AT RHIC. (open access)

HELIUM FLOW INDUCED ORBIT JITTER AT RHIC.

Horizontal beam orbit jitter at frequencies around 10 Hz has been observed in RHIC for several years. The distinct frequencies of this jitter have been found at superconducting low-beta quadrupole triplets around the ring, where they coincide with mechanical modes of the cold masses. Recently, we have identified liquid helium flow as the driving force of these oscillations.
Date: May 16, 2005
Creator: Montag, C.; He, P.; Jia, L.; Nicoletti, A.; Satogata, T. & AL., ET
System: The UNT Digital Library
Synchrotron Radiation in Erhic Interaction Region. (open access)

Synchrotron Radiation in Erhic Interaction Region.

The electron-ion collider eRHIC [1] currently under study at BNL consists of an electron storage ring added to the existing RHIC complex. The interaction region of this facility has to provide the required low-beta focusing while accommodating the synchrotron radiation generated by beam separation close to the interaction point. In the current design, the synchrotron radiation caused by 10GeV electrons bent by separator dipole magnets will be guided through the interaction region and dumped 5m downstream. However, it is unavoidable to stop a fraction of the photons at the septum where the electron and ion vacuum systems are separated. In order to protect the septum and minimize the backward synchrotron radiation, an absorber and collimation system will be employed. In this paper, we fist present the overview of the current design of the eRHIC interaction region with special emphasis on the synchrotron radiation. Then the initial design of the absorber, including its geometrical and physical property, will be described. Finally, our initial investigation of synchrotron radiation in the eRHIC interaction region, especially a simulation of the backward scattering from the absorber, will be presented.
Date: May 16, 2005
Creator: Beebe-Wang, J. J.; Montag, C. & AL., ET
System: The UNT Digital Library
COMPARISON OF OFF-LINE IR BUMP AND ACTION-ANGLE KICK MINIMIZATION. (open access)

COMPARISON OF OFF-LINE IR BUMP AND ACTION-ANGLE KICK MINIMIZATION.

The interaction region bump (IR bump) nonlinear correction method has been used for the sextupole and octupole field error on-line corrections in the Relativistic Heavy Ion Collider (RHIC) . Some differences were found for the sextupole and octupole corrector strengths between the on-line IR bump correction and the predictions from the action-angle kick minimization. In this article, we compare the corrector strengths from these two methods based on the RHIC Blue ring lattice with the IR nonlinear modeling. The comparison confirms the differences between resulting corrector strengths. And the reason for the differences is found and discussed.
Date: May 16, 2005
Creator: Luo, Y.; Pilat, F.; Ptitsyn, V.; Trbojevic, D. & Wei, J.
System: The UNT Digital Library
Upgrade of Rhic Vacuum Systems for High Luminosity Operation. (open access)

Upgrade of Rhic Vacuum Systems for High Luminosity Operation.

With increasing ion beam intensity during recent RHIC operations, rapid pressure rises of several decades were observed at most warm sections and at a few cold sections. The pressure rises are associated with electron multi-pacting, electron stimulated desorption and beam ion induced desorption and have been one of the major intensity and luminosity limiting factors for RHIC. Improvement of the warm sections has been carried out in the last few years. Extensive in-situ bakes, additional UHV pumping and anti-grazing ridges have been implemented. Several hundred meters of NEG coated beam pipes have been installed and activated. Vacuum monitoring and logging were enhanced. Preventive measures, such as pumping before cool down to reduce monolayer condensates, were also taken to suppress the pressure rises in the cold sections. The effectiveness of these measures in reducing the pressure rises during machine studies and during physics runs are discussed and summarized.
Date: May 16, 2005
Creator: Hseuh, H. C.; Mapes, M.; Smart, L. A.; Todd, R. & Weiss, D.
System: The UNT Digital Library
Injector Linac for the Bnl Super Neutrino Beam Project. (open access)

Injector Linac for the Bnl Super Neutrino Beam Project.

BNL plans to upgrade the AGS proton beam power from the present 0.14 MW to higher than 1.0 MW and beyond for a neutrino facility. We have examined possible upgrade to the AGS accelerator complex that would meet the requirements of the proton beam of 1.0 MW for neutrino superbeam facility. The major contribution for the higher power is from the increase of the repetition rate of the AGS from 0.3 Hz to 2.5 Hz, with moderate increase from the intensity. To increase the AGS repetition rate we are proposing to replace booster with a 1.5 GeV linac. We will replace part of existing 200 MeV linac with coupled cavity structure from 116 MeV to 400 MeV and then add an additional 1.1 GeV superconducting linac to reach a final energy of 1.5 GeV for direct H{sup -} injection into the AGS. We will present possible choices for the upgrade and our choice and its design.
Date: May 16, 2005
Creator: Raparia, D.; Alessi, J.; Ruggiero, A. & Weng, W. T.
System: The UNT Digital Library
The Extraction Lambertson Septum Magnet of the Sns. (open access)

The Extraction Lambertson Septum Magnet of the Sns.

In the Spallation Neutron Source, after multiple injections to an accumulator ring, a final extraction delivers the full proton beam to the target, achieved by a series of kickers and a thin septum magnet. Here we discuss the lattice geometry, beam dynamics and optics, and the vacuum, electromagnetic and mechanical design aspects of the Extraction Lambertson Septum Magnet (ELS). Relevant data are established. Vector calculus is solved for pitch and roll angles, which are shown schematically in magnet sections.
Date: May 16, 2005
Creator: J., Rank; Miglionico, G.; Raparia, D.; Tsoupas, N.; Tuozzolo, J. & Lee, Y. Y.
System: The UNT Digital Library
High Energy Pulsed Power System for Ags Super Neutrino Focusing Horn. (open access)

High Energy Pulsed Power System for Ags Super Neutrino Focusing Horn.

This paper present a preliminary design of a 300 kA, 2.5 Hz pulsed power system. This system will drive the focusing horn of proposed Brookhaven AGS Neutrino Super Beam Facility for Very Long Baseline Neutrino Oscillation Experiment. The peak output power of the horn pulsed power system will reach Giga-watts, and the upgraded AGS will be capable of delivering 1 MW in beam power.
Date: May 16, 2005
Creator: Zhang, S. Y.; Sandberg, J. & Weng, W. T.
System: The UNT Digital Library
TEST RESULTS OF HTS COILS AND AN R AND D MAGNET FOR RIA. (open access)

TEST RESULTS OF HTS COILS AND AN R AND D MAGNET FOR RIA.

This paper presents the successful construction and test results of a magnetic mirror model for the Rare Isotope Accelerator (RIA) that is based on High Temperature Superconductors (HTS). In addition, the performance of thirteen coils (each made with {approx}220 meters of commercially available HTS tape) is also presented. The proposed HTS magnet is a crucial part of the R&D for the Fragment Separator region where the magnets are subjected to several orders of magnitude more radiation and energy deposition than typical beam line and accelerator magnets receive during their entire lifetime. A preliminary design of an HTS dipole magnet for the Fragment Separator region is also presented.
Date: May 16, 2005
Creator: Gupta, R.; Anerella, M.; Harrison, M.; Schmalzle, J.; Sampson, W. & Zeller, A.
System: The UNT Digital Library