Setup and performance of RHIC for the 2008 run with deuteron-gold collisions. (open access)

Setup and performance of RHIC for the 2008 run with deuteron-gold collisions.

This year (2008) deuterons and gold ions were collided in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) for the first time since 2003. The setup and performance of the collider for the 2008 run is reviewed with a focus on improvements that have led to an order of magnitude increase in luminosity over that achieved in the 2003 run.
Date: June 23, 2008
Creator: Gardner,C.; Abreu, N.P.; Ahren, L.; Alessi, J.; Bai, M. & al., et
System: The UNT Digital Library
AGS polarized proton operation in run 8. (open access)

AGS polarized proton operation in run 8.

Dual partial snake scheme has been used for the Brookhaven AGS (Alternating Gradient Synchrotron) polarized proton operation for several years. It has provided polarized proton beams with 1.5 x 10{sup 11} intensity and 65% polarization for RHIC spin program. There is still residual polarization loss. Several schemes such as putting horizontal tune into the spin tune gap, and injection-on-the-fly were tested in the AGS to mitigate the loss. This paper presents the experiment results and analysis.
Date: June 23, 2008
Creator: Huang, H.; Ahrens, L.; Bai, M.; Brown, K. A.; Gardner, C.; Glenn, J. W. et al.
System: The UNT Digital Library
Injection and Acceleration of Au31+ in the BNL AGS. (open access)

Injection and Acceleration of Au31+ in the BNL AGS.

Injection and acceleration of ions in a lower charge state reduces space charge effects, and, if further elcctron stripping is needed, may allow elimination of a stripping stage and the associated beam losses. The former is of interest to the accelerators in the GSI FAIR complex, the latter for BNL RHIC collider operation at energies lower than the current injection energy. Lower charge state ions, however, have a higher likelihood of electron stripping which can lead to dynamic pressures rises and subsequent beam losses. We report on experiments in the AGS where Au{sup 31+} ions were injected and accelerated instead of the normally used Au{sup 77+} ions. Beam intensities and the average pressure in the AGS ring are recorded, and compared with calculations for dynamic pressures and beam losses. The experimental results will be used to benchmark the StrahlSim dynamic vacuum code and will be incorporated in the GSI FAIR SIS100 design.
Date: June 23, 2008
Creator: Fischer, W.; Ahrens, L.; Brown, K.; Gardner, C.; Glenn, W.; Huang, H. et al.
System: The UNT Digital Library
Extracellular matrix control of mammary gland morphogenesis and tumorigenesis: insights from imaging (open access)

Extracellular matrix control of mammary gland morphogenesis and tumorigenesis: insights from imaging

The extracellular matrix (ECM), once thought to solely provide physical support to a tissue, is a key component of a cell's microenvironment responsible for directing cell fate and maintaining tissue specificity. It stands to reason, then, that changes in the ECM itself or in how signals from the ECM are presented to or interpreted by cells can disrupt tissue organization; the latter is a necessary step for malignant progression. In this review, we elaborate on this concept using the mammary gland as an example. We describe how the ECM directs mammary gland formation and function, and discuss how a cell's inability to interpret these signals - whether as a result of genetic insults or physicochemical alterations in the ECM - disorganizes the gland and promotes malignancy. By restoring context and forcing cells to properly interpret these native signals, aberrant behavior can be quelled and organization re-established. Traditional imaging approaches have been a key complement to the standard biochemical, molecular, and cell biology approaches used in these studies. Utilizing imaging modalities with enhanced spatial resolution in live tissues may uncover additional means by which the ECM regulates tissue structure, on different length scales, through its pericellular organization (short-scale) and by biasing …
Date: October 23, 2008
Creator: Ghajar, Cyrus M & Bissell, Mina J
System: The UNT Digital Library
Tissue architecture and function: dynamic reciprocity via extra- and intra-cellular matrices (open access)

Tissue architecture and function: dynamic reciprocity via extra- and intra-cellular matrices

Mammary gland development, functional differentiation, and homeostasis are orchestrated and sustained by a balance of biochemical and biophysical cues from the organ's microenvironment. The three-dimensional microenvironment of the mammary gland, predominantly 'encoded' by a collaboration between the extracellular matrix (ECM), hormones, and growth factors, sends signals from ECM receptors through the cytoskeletal intracellular matrix to nuclear and chromatin structures resulting in gene expression; the ECM in turn is regulated and remodeled by signals from the nucleus. In this chapter, we discuss how coordinated ECM deposition and remodeling is necessary for mammary gland development, how the ECM provides structural and biochemical cues necessary for tissue-specific function, and the role of the cytoskeleton in mediating the extra - to intracellular dialogue occurring between the nucleus and the microenvironment. When operating normally, the cytoskeletal-mediated dynamic and reciprocal integration of tissue architecture and function directs mammary gland development, tissue polarity, and ultimately, tissue-specific gene expression. Cancer occurs when these dynamic interactions go awry for an extended time.
Date: December 23, 2008
Creator: Xu, Ren; Boudreau, Aaron & Bissell, Mina J
System: The UNT Digital Library
Analysis of intensity instability threshold at transition in RHIC. (open access)

Analysis of intensity instability threshold at transition in RHIC.

The beam intensity of ion beams in RHIC is limited by a fast transverse instability at transition, driven by the machine impedance and electron clouds. For gold and deuteron beams we analyze the dependence of the instability threshold on beam and machine parameters from recent operational data and dedicated experiments. We fit the machine impedance to the experimental data.
Date: June 23, 2008
Creator: Fischer, W.; Blaskiewicz, M.; Cameron, P.; Montag, C. & Ptitsyn, V.
System: The UNT Digital Library
RHIC polarized proton performance in run-8. (open access)

RHIC polarized proton performance in run-8.

During Run-8, the Relativistic Heavy Ion Collider (RHIC) provided collisions of spin-polarized proton beams at two interaction regions. Helical spin rotators at these two interaction regions were used to control the spin orientation of both beams at the collision points. Physics data were taken with different orientations of the beam polarization. We present recent developments and improvements as well as the luminosity and polarization performance achieved during Run-8.
Date: June 23, 2008
Creator: Montag, C.; Abreu, N.; Ahrens, L.; Bai, M.; Barton, D. & al., et
System: The UNT Digital Library
RHIC and its upgrade programmes. (open access)

RHIC and its upgrade programmes.

As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species. After a brief review of the achieved performance the presentation will give an overview of the plans, challenges and status of machine upgrades, that range from a new heavy ion pre-injector and beam cooling at 100 GeV to a high luminosity electron-ion collider.
Date: June 23, 2008
Creator: Roser, T.
System: The UNT Digital Library
Proceedings of the 30th Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring (open access)

Proceedings of the 30th Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring

These proceedings contain papers prepared for the 30th Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, held 23-25 September, 2008 in Portsmouth, Virginia. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Technical Applications Center (AFTAC), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States’ capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.
Date: September 23, 2008
Creator: Wetovsky, Marv A; Aguilar-chang, Julio; Arrowsmith, Marie; Arrowsmith, Stephen; Baker, Diane; Begnaud, Michael et al.
System: The UNT Digital Library