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Parton showers are widely used to generate fully exclusive final states needed to compare theoretical models to experimental observations. While, in general, parton showers give a good description of the experimental data, the precise functional form of the probability distribution underlying the event generation is generally not known. The reason is that realistic parton showers are required to conserve four-momentum at each vertex. In this paper we investigate in detail how four-momentum conservation is enforced in a standard parton shower and why this destroysthe analytic control of the probability distribution. We show how to modify a parton shower algorithm such that it conserves four-momentum at each vertex, but for which the full analytic form of the probability distribution is known. We then comment how this analytic control can be used to match matrix element calculations with parton showers, and to estimate effects of power corrections and other uncertainties in parton showers.

We study the smooth non-supersymmetric three-charge microstatesof Jejjala, Madden, Ross and Titchener using Kaluza-Klein reductions of the solutions to five and four dimensions. Our aim is to improve our understanding of the relation between these non-supersymmetric solutions and the well-studied supersymmetric cases. We find some surprising qualitative differences. In the five-dimensional description, the solution has orbifold fixed points which break supersymmetry locally, so the geometries cannot be thought of as made up of separate half-BPS centers. In the four-dimensional description, the two singularities in the geometry are connected by a conical singularity, which makes it impossible to treat them independently and assign unambiguous brane charges to these centers.

The historical trend of increasing single CPU performancehas given way to roadmap of increasing core count. The challenge ofeffectively utilizing these multi-core chips is just starting to beexplored by vendors and application developers alike. In this study, wepresent some performance measurements of several complete scientificapplications on single and dual core Cray XT3 and XT4 systems with a viewto characterizing the effects of switching to multi-core chips. Weconsider effects within a node by using applications run at lowconcurrencies, and also effects on node-interconnect interaction usinghigher concurrency results. Finally, we construct a simple performancemodel based on the principle on-chip shared resource--memorybandwidth--and use this to predict the performance of the forthcomingquad-core system.

This White Paper summarizes the outcome of the Town Meeting on Phases of QCD that took place January 12-14, 2007 at Rutgers University, as part of the NSAC 2007 Long Range Planning process. The meeting was held in conjunction with the Town Meeting on Hadron Structure, including a full day of joint plenary sessions of the two meetings. Appendix A.1 contains the meeting agenda. This Executive Summary presents the prioritized recommendations that were determined at the meeting. Subsequent chapters present the essential background to the recommendations. While this White Paper is not a scholarly article and contains few references, it is intended to provide the non-expert reader

Liquid array technology has previously been used to show proof-of-principle of a multiplexed non structural protein serological assay to differentiate foot-and-mouth infected and vaccinated animals. The current multiplexed assay consists of synthetically produced peptide signatures 3A, 3B and 3D and recombinant protein signature 3ABC in combination with four controls. To determine diagnostic specificity of each signature in the multiplex, the assay was evaluated against a naive population (n = 104) and a vaccinated population (n = 94). Subsequently, the multiplexed assay was assessed using a panel of bovine sera generated by the World Reference Laboratory for foot-and-mouth disease in Pirbright, UK. This sera panel has been used to assess the performance of other singleplex ELISA-based non-structural protein antibody assays. The 3ABC signature in the multiplexed assay showed comparative performance to a commercially available non-structural protein 3ABC ELISA (Cedi test{reg_sign}) and additional information pertaining to the relative diagnostic sensitivity of each signature in the multiplex is acquired in one experiment. The encouraging results of the evaluation of the multiplexed assay against a panel of diagnostically relevant samples promotes further assay development and optimization to generate an assay for routine use in foot-and-mouth disease surveillance.

I explore a different type of approximation to the exactanisotropic wave velocities as a function of incidence angle invertically transversely isotropic (VTI) media. This method extends theThomsen weak anisotropy approach to stronger anisotropy withoutsignificantly affecting the simplicity of the formulas. One importantimprovement is that the peak of the quasi-SV-wave speed vsv(theta) islocated at the correct incidence angle theta= theta max, rather thanalways being at the position theta = 45o, which universally holds forThomsen's approximation although max theta = 45o is actually nevercorrect for any VTI anisotropic medium. The magnitudes of all the wavespeeds are also more closely approximated for all values of the incidenceangle. Furthermore, the value of theta max (which is needed in the newformulas) can be deduced from the same data that are typically used inthe weak anisotropy data analysis. The two examples presented are basedon systems having vertical fractures. The first set of model fractureshas their axes of symmetry randomly oriented in the horizontal plane.Such a system is then isotropic in the horizontal plane and, therefore,exhibits vertical transverse isotropic (VTI) symmetry. The second set offractures also has axes of symmetry in the horizontal plane, but it isassumed these axes are aligned so that the system exhibits horizontaltransverse …

We have developed a new protocol for using MolecularInversion Probes (MIP) to accurately and specifically measure allele copynumber (ACN). The new protocol provides for significant improvementsincluding the reduction of input DNA (from 2?g) by more than 25 fold (to75ng total genomic DNA), higher overall precision resulting in one orderof magnitude lower false positive rate, and greater dynamic range withaccurate absolute copy number up to 60 copies.

A long-standing problem in the field of laser-plasma interactions is to successfully employ multiple-ion species plasmas to reduce stimulated Brillouin scattering (SBS) in inertial confinement fusion (ICF) hohlraum conditions. Multiple-ion species increase significantly the linear Landau damping for acoustic waves. Consequently, recent hohlraum designs for indirect-drive ignition on the National Ignition Facility investigate wall liner material options so that the liner gain for parametric instabilities will be below threshold for the onset SBS. Although the effect of two-ion species plasmas on Landau damping has been directly observed with Thomson scattering, early experiments on SBS in these plasmas have suffered from competing non-linear effects or laser beam filamentation. In this study, a reduction of SBS scattering to below the percent level has been observed in hohlraums at Omega that emulate the plasma conditions in an indirect drive ICF experiments. These experiments have measured the laser-plasma interaction processes in ignition-relevant high-electron temperature regime demonstrating Landau damping as a controlling process for SBS. The hohlraums have been filled with various fractions of CO{sub 2} and C{sub 3}H{sub 8} varying the ratio of the light (H) to heavy (C and O) ion density from 0 to 2.6. They have been heated by 14.5 kJ …

Nuclear reaction study with radioactive ion beams is one of the most exciting research topics in modern nuclear physics. The development of radioactive ion beams has allowed nuclear scientists and engineers to explore many unknown exotic nuclei far from the valley of nuclear stability, and to further our understanding of the evolution of the universe. The recently developed radioactive ion beam facility at the Lawrence Berkeley National Laboratory's 88-inch cyclotron is denoted as BEARS and provides {sup 11}C, {sup 14}O and {sup 15}O radioactive ion beams of high quality. These moderate to high intensity, proton-rich radioactive ion beams have been used to explore the properties of unstable nuclei such as {sup 12}N and {sup 15}F. In this work, the proton capture reaction on {sup 11}C has been evaluated via the indirect d({sup 11}C, {sup 12}N)n transfer reaction using the inverse kinematics method coupled with the Asymptotic Normalization Coefficient (ANC) theoretical approach. The total effective {sup 12}N {yields} {sup 11}C+p ANC is found to be (C{sub eff}{sup 12{sub N}}){sup 2} = 1.83 {+-} 0.27 fm{sup -1}. With the high {sup 11}C beam intensity available, our experiment showed excellent agreement with theoretical predictions and previous experimental studies. This study also indirectly confirmed …

Seismic wave propagation through the earth is often stronglyaffected by the presence of fractures. When these fractures are filledwith fluids (oil, gas, water, CO2, etc.), the type and state of the fluid(liquid or gas) can make a large difference in the response of theseismic waves. This paper summarizes recent work on methods ofdeconstructing the effects of fractures, and any fluids within thesefractures, on seismic wave propagation as observed in reflection seismicdata. One method explored here is Thomsen's weak anisotropy approximationfor wave moveout (since fractures often induce elastic anisotropy due tononuniform crack-orientation statistics). Another method makes use ofsome very convenient fracture parameters introduced previously thatpermit a relatively simple deconstruction of the elastic and wavepropagation behavior in terms of a small number of fracture parameters(whenever this is appropriate, as is certainly the case for small crackdensities). Then, the quantitative effects of fluids on thesecrack-influence parameters are shown to be directly related to Skempton scoefficient B of undrained poroelasticity (where B typically ranges from0 to 1). In particular, the rigorous result obtained for the low crackdensity limit is that the crack-influence parameters are multiplied by afactor (1 ? B) for undrained systems. It is also shown how fractureanisotropy affects Rayleigh wave speed, and …

Advances in the development of laser-produced x-ray sources have enabled a new class of high-energy density physics experiments. Powerful narrow-bandwidth x rays penetrate through short-lived hot dense states of matter and probe the physical properties with spectrally resolved x-ray scattering. Experiments from isochorically-heated plasmas with electron densities in the range of solid density and above have been demonstrated allowing for the first time exploration of the microscopic properties of dense matter regime close to strongly-coupled and Fermi degenerate conditions. Backscatter measurements have accessed the non-collective Compton scattering regime, which provides accurate diagnostic information on the temperature, density and ionization states. The forward scattering spectrum has been shown to measure the collective plasmon oscillations. Besides extracting the standard plasma parameters, density and temperature, forward scattering yields new observables such as a direct measure of collisions, quantum effects and detailed balance. In this talk, we will discuss new results important for applications of this technique for novel experiments in a wide range of research areas such as inertial confinement fusion, radiation-hydrodynamics, material science, and laboratory astrophysics.

The cylindrical thruster differs significantly in its underlying physical mechanisms from the conventional annular Hall thruster. It features high ionization efficiency, quiet operation, ion acceleration in a large volume-to-surface ratio channel, and performance comparable with the state-of-the-art conventional Hall thrusters. Very significant plume narrowing, accompanied by the increase of the energetic ion fraction and improvement of ion focusing, led to 50%–60% increase of the thruster anode efficiency. These improvements were achieved by overrunning the discharge current in the magnetized thruster plasma.

We predict the upper bound on the dissociation temperatures of different quarkonium states.

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This paper explores the performance of the tenth-order central spatial scheme and derives the accompanying energy-norm stable summation-by-parts (SBP) boundary operators. The objective is to employ the resulting tenth-order spatial differencing with the stable SBP boundary operators as a base scheme in the framework of adaptive numerical dissipation control in high order multistep filter schemes of Yee et al. (1999), Yee and Sj{umlt o}green (2002, 2005, 2006, 2007), and Sj{umlt o}green and Yee (2004). These schemes were designed for multiscale turbulence flows including strong shock waves and combustion.

We present the predictions for hadron multiplicities in pp, pA and AA collisions at the LHC based on our approach to the Color Glass Condensate.

Job Control Waste (JCW) at the Savannah River Site (SRS) Solid Waste Management Facilities (SWMF) may be disposed of in special containers, and the analysis of these containers requires developing specific analysis methodologies. A method has been developed for the routine assay of prohibited items (liquids, etc.) contained in a 30-gallon drum that is then placed into a 55-gallon drum. Method development consisted of system calibration with a NIST standard at various drum-to-detector distances, method verification with a liquid sample containing a known amount of Pu-238, and modeling the inner container using Ortec Isotopic software. Using this method for measurement of the known standard in the drum-in-drum configuration produced excellent agreement (within 15%) with the known value. Savannah River Site Solid Waste Management also requested analysis of waste contained in large black boxes (commonly 18-feet x 12-feet x 7-feet) stored at the SWMF. These boxes are frequently stored in high background areas and background radiation must be considered for each analysis. A detection limit of less than 150 fissile-gram-equivalents (FGE) of TRU waste is required for the black-box analyses. There is usually excellent agreement for the measurements at different distances and measurement uncertainties of about 50% are obtained at distances …

This project falls under the Technology Innovation and Diffusion topic of the Integrated Assessment of Climate Change Research Program. The objective was to better understand the critical variables that affect the rate of penetration of large-scale electricity technologies in order to improve their representation in integrated assessment models. We conducted this research in six integrated tasks. In our first two tasks, we identified potential factors that affect penetration rates through discussions with modeling groups and through case studies of historical precedent. In the next three tasks, we investigated in detail three potential sets of critical factors: industrial conditions, resource conditions, and regulatory/environmental considerations. Research to assess the significance and relative importance of these factors involved the development of a microeconomic, system dynamics model of the US electric power sector. Finally, we implemented the penetration rate models in an integrated assessment model. While the focus of this effort is on carbon capture and sequestration technologies, much of the work will be applicable to other large-scale energy conversion technologies.