CDF has resumed the top quark mass measurement with upgraded detectors and Tevatron complex. High statistics should allow us to determine the top mass with an uncertainty of a few GeV/c{sup 2} by the end of Run II. The current measured value, using an integrated luminosity of {approx} 108 pb{sup -1}, is 177.5{sub -9.4}{sup +12.7} (stat.) {+-} 7.1(syst.) GeV/c{sup 2} (lepton + jets with one b-jet tagged mode: the current best mode), which is consistent with RunI measurements.

During the last decade the scientific computing community has optimized many applications for execution on superscalar computing platforms. The recent arrival of the Japanese Earth Simulator has revived interest in vector architectures especially in the US. It is important to examine how to port our current scientific applications to the new vector platforms and how to achieve high performance. The success of porting these applications will also influence the acceptance of new vector architectures. In this paper, we first investigate the memory performance characteristics of the Cray X1, a recently released vector platform, and determine the most influential performance factors. Then, we examine how to optimize applications tuned on superscalar platforms for the Cray X1 using its performance characteristics as guidelines. Finally, we evaluate the different types of optimizations used, the effort for their implementations, and whether they provide any performance benefits when ported back to superscalar platforms.

We present the type Ia rate measurement based on two EROS supernova search campaigns (in 1999 and 2000). Sixteen supernovae identified as type Ia were discovered. The measurement of the detection efficiency, using a Monte Carlo simulation, provides the type Ia supernova explosion rate at a redshift {approx} 0.13. The result is 0.125{sub -0.034-0.028}{sup +0.044+0.028} h{sub 70}{sup 2} SNu where 1 SNu = 1 SN/10{sup 10} L{sub {circle_dot}}{sup B}/century. This value is compatible with the previous EROS measurement (Hardin et al. 2000), done with a much smaller sample, at a similar redshift. Comparison with other values at different redshifts suggests an evolution of the type Ia supernova rate.

This paper presents the results of a comparison of three parallel algebraic multigrid (AMG) preconditioners for structural mechanics applications. In particular, they are interested in investigating both the scalability and robustness of the preconditioners. Numerical results are given for a range of structural mechanics problems with various degrees of difficulty.

The authors examine theoretically conduction processes near the Fermi energy of thin layers of zincblende structure half metals, using as an example a superlattice consisting of monolayers of GaAs and MnAs, a bilayer of CrAs, and a bilayer of GaAs. By artificially separating bilayers, they show that non-fourfold coordinated Cr states thwart half metallicity. However, capping the metal-As bilayers restores half metallicity and ballistic conduction of electrons around 0.3 eV above the Fermi level will give nearly 100% spin-polarized transmission in the direction of the thin superlattice. Recent developments suggest atomic layer epitaxy can be used to produce such thin layers for spintronics applications.

A power lead tower containing the multi-tube power leads is designed and under fabrication for the superconducting IR quadrupole magnets in the Beijing Electron Position Collider Upgrade (BEPCII). The lead tower consists of six pairs of gas-cooled leads for seven superconducting coils at various operating currents. The power lead is designed in a modular fashion, which can be easily applied to suit different operating current. The end copper block of the tube lead has a large cold mass that provide a large time constant in case of cooling flow interruption. A novel cryogenic electrical isolator is used for the leads.

A pair of superconducting interaction region quadrupole magnets for BEPCII was designed and fabricated at Brookhaven National Laboratory, USA. The cryogenic system for the IR magnets was designed at Harbin Institute of Technology, China. This paper provides the results of thermal fluid modeling for the magnet cryostat. The numerical analyses were carried out for two types of cooling methods, the subcooled liquid helium and the supercritical helium flow. The pressure and temperature changes in the cooling circuits are given.

Beijing Electron-Positron Collider Upgrade (BEPCII) requires three types of superconducting facilities, including one pair of SRF cavities, one pair of interaction region quadrupole magnets, and one detector solenoid magnet. The cryo-plant for BEPCII has a total cooling capacity of 1kW at 4.5K, which is composed of two separate helium refrigerators of 500W each. Two refrigerators share the same gas storage and recovery system. The engineering design for the cryogenic systems, including power leads, control dewars, subcooler, cryogenic valve boxes, cryogenic transfer-lines and cryogenic controls, is completed. The production of its subsystem is under way. This paper summarizes the progress in cryogenics of the BEPCII project.

Host-pathogen interactions result in protein expression changes within both the host and the pathogen. Here, results from proteomic characterization of host response following exposure to Yersinia pestis, the causative agent of plague, and to two near neighbors, Y. pseudotuberculosis and Y. enterocolitica, are reported. Human monocyte-like cells were chosen as a model for macrophage immune response to pathogen exposure. Two-dimensional electrophoresis followed by mass spectrometry was used to identify host proteins with differential expression following exposure to these three closely related Yersinia species. This comparative proteomic characterization of host response clearly shows that host protein expression patterns are distinct for the different pathogen exposures, and contributes to further understanding of Y. pestis virulence and host defense mechanisms. This work also lays the foundation for future studies aimed at defining biomarkers for presymptomatic detection of plague.

Three kinds of superconducting device are to be constructed at interaction regions in the upgrade of Beijing Electron-Positron Collider (BEPCII). Two sets of refrigerators with each capacity of 500W at 4.5K are adopted to provide the refrigeration for them. The cryogenic systems to support the operation of the superconducting facilities are under design by Harbin Institute of Technology in China. This paper presents the current design of main cryogenic facilities.

Six pairs of low current leads are used for the superconducting interaction quadruple magnets (SCQ) in the Beijing Electron Positron Collider Upgrade (BEPCII). This paper presents analyses on the magnetic field induced by the current lead bundle as well as the magnetic forces on the leads. The thermal stress of the single lead is investigated. The stress of interference fitting for a novel insulator used for the current leads at various operating temperatures is analyzed.

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We have demonstrated a 10 Hz Ni-like Mo X-ray laser operating at 18.9 nm with 150 mJ total pump energy by employing a novel pumping scheme. The grazing incidence scheme is described, where a picosecond pulse is incident at a grazing angle to a Mo plasma column produced by a slab target irradiated by a 200 ps laser pulse. This scheme uses refraction of the short pulse at a pre-determined electron density to increase absorption to pump a specific gain region. The high efficiency inherent to this scheme allows a reduction in the pump energy where 70 mJ long pulse energy and 80 mJ short pulse energy are sufficient to produce lasing at a 10 Hz repetition rate. Under these conditions and by optimizing the delay between the pulses, we achieve strong amplification and saturation for 4 mm long targets.

Ab initio total energy calculations based on the exact muffin-tin orbitals (EMTO) theory are used to determine the high pressure and low temperature phase diagram of Ce and Th metals as well as the Ce{sub 43}Th{sub 57} disordered alloy. The compositional disorder for the alloy is treated in the framework of the coherent potential approximation (CPA). Equation of state for Ce, Th and Ce{sub 43}Th{sub 57} has been calculated up to 1 Mbar in good comparison with experimental data: upon compression the Ce-Th system undergoes crystallographic phase transformation from an fcc to a bct structure and the transition pressure increases with Th content in the alloy.

Puzzling discrepancies between on the one hand quantum mechanical (QM) electron impact calculations of isolated ion lines and on the other hand experimental data and nonperturbative semiclassical (SC) calculations are reviewed. The origin of these discrepancies was a standard line-broadening literature estimate of the wavefunction extent. The nonperturbative semiclassical calculations are further improved by dropping the long-range approximation and allowing penetrating collisions. This results in excellent agreement with fully quantal calculations for the case of the BIII 2s-2p line. On the other hand the standard perturbative semiclassical method is inadequate even in this particular example, where perturbation theory is valid. Further, the assumption of neglecting the back-reaction in semiclassical calculations is examined.

The Non-Equilibrium Zeldovich - von Neumann - Doring (NEZND) theory of self-sustaining detonation identified amplification of pressure wavelets during equilibration of vibrationally excited reaction products in the reaction zone as the physical mechanism by which exothermic chemical energy release sustains detonation waves. This mechanism leads to the formation of the well-known, complex three-dimensional structure of a self-sustaining detonation wave. This amplification mechanism is postulated to be a general property of subsonic and supersonic reactive flows occurring during: shock to detonation transition (SDT); hot spot ignition and growth; deflagration to detonation transition (DDT); flame acceleration by shock or compression waves; and acoustic (sound) wave amplification. The existing experimental and theoretical evidence for pressure wave amplification by chemical energy release into highly vibrationally excited product molecules under these reactive flow conditions is reviewed in this paper.