1,229 research outputs found
Color Transparent GPDs?
The relation between GPD's and color transparency is explored. The discovery
of color transparency in pionic diffractive dissociation reactions allows us to
make specific predictions for the behavior of the pion generalized parton
distribution, and provide a further test of any model of the pion form factor.Comment: 12 pages, 3 figure
Experimental Evidence for Non-Thermal Contributions to Plasmon-Enhanced Electrochemical Oxidation Reactions
Photocatalysis based on plasmonic nanoparticles has emerged as a promising approach to facilitate light-driven reactions under far milder conditions than thermal catalysis. Several effects, such as strong local electromagnetic fields, increased electron and lattice temperatures, or the transfer of non-thermal charge carriers could contribute to the reaction rate enhancement. In order to understand plasmon-enhanced catalysis and to enable plasmonic platforms, a distinction between the different underlying effects is required. We investigate the electrochemical model reactions oxidative hydroxide adsorption and glucose oxidation and deconvolve the enhancement processes via their dependence on excitation wavelength. We observe that non-thermal effects contribute significantly to the plasmonic enhancement
Application benchmark results for Big Red, an IBM e1350 BladeCenter Cluster
The purpose of this report is to present the results of benchmark tests with Big Red, an IBM e1350 BladeCenter Cluster. This report is particularly focused on providing details of system architecture and test run results in detail to allow for analysis in other reports and comparison with other systems, rather than presenting such analysis here
Performance and quality of service of data and video movement over a 100Â Gbps testbed
AbstractDigital instruments and simulations are creating an ever-increasing amount of data. The need for institutions to acquire these data and transfer them for analysis, visualization, and archiving is growing as well. In parallel, networking technology is evolving, but at a much slower rate than our ability to create and store data. Single fiber 100 Gbps networking solutions have recently been deployed as national infrastructure. This article describes our experiences with data movement and video conferencing across a networking testbed, using the first commercially available single fiber 100 Gbps technology. The testbed is unique in its ability to be configured for a total length of 60, 200, or 400 km, allowing for tests with varying network latency. We performed low-level TCP tests and were able to use more than 99.9% of the theoretical available bandwidth with minimal tuning efforts. We used the Lustre file system to simulate how end users would interact with a remote file system over such a high performance link. We were able to use 94.4% of the theoretical available bandwidth with a standard file system benchmark, essentially saturating the wide area network. Finally, we performed tests with H.323 video conferencing hardware and quality of service (QoS) settings, showing that the link can reliably carry a full high-definition stream. Overall, we demonstrated the practicality of 100Â Gbps networking and Lustre as excellent tools for data management
The TANAMI Program
TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond
Interferometry) is a monitoring program to study the parsec-scale structures
and dynamics of relativistic jets in active galactic nuclei (AGN) of the
Southern Hemisphere with the Long Baseline Array and associated telescopes.
Extragalactic jets south of -30 degrees declination are observed at 8.4 GHz and
22 GHz every two months at milliarcsecond resolution. The initial TANAMI sample
is a hybrid radio and gamma-ray selected sample since the combination of VLBI
and gamma-ray observations is crucial to understand the broadband emission
characteristics of AGN.Comment: Confernce Proceedings for "X-ray Astronomy 2009" (Bologna), 3 pages,
3 figures, needs cls-fil
The scalar gluonium correlator: large-beta_0 and beyond
The investigation of the scalar gluonium correlator is interesting because it
carries the quantum numbers of the vacuum and the relevant hadronic current is
related to the anomalous trace of the QCD energy-momentum tensor in the chiral
limit. After reviewing the purely perturbative corrections known up to
next-next-to-leading order, the behaviour of the correlator is studied to all
orders by means of the large-beta_0 approximation. Similar to the QCD Adler
function, the large-order behaviour is governed by the leading ultraviolet
renormalon pole. The structure of infrared renormalon poles, being related to
the operator product expansion are also discussed, as well as a low-energy
theorem for the correlator that provides a relation to the renormalisation
group invariant gluon condensate, and the vacuum matrix element of the trace of
the QCD energy-momentum tensor.Comment: 14 pages, references added, discussion of IR renormalon pole at u=3
extended, similar version to appear in JHE
Hierarchical propagation of structural features in protein nanomaterials
Natural high-performance materials have inspired the exploration of novel materials from protein building blocks. The ability of proteins to self-organize into amyloid-like nanofibrils has opened an avenue to new materials by hierarchical assembly processes. As the mechanisms by which proteins form nanofibrils are becoming clear, the challenge now is to understand how the nanofibrils can be designed to form larger structures with defined order. We here report the spontaneous and reproducible formation of ordered microstructure in solution cast films from whey protein nanofibrils. The structural features are directly connected to the nanostructure of the protein fibrils, which is itself determined by the molecular structure of the building blocks. Hence, a hierarchical assembly process ranging over more than six orders of magnitude in size is described. The fibril length distribution is found to be the main determinant of the microstructure and the assembly process originates in restricted capillary flow induced by the solvent evaporation. We demonstrate that the structural features can be switched on and off by controlling the length distribution or the evaporation rate without losing the functional properties of the protein nanofibrils
Hierarchical propagation of structural features in protein nanomaterials
Natural high-performance materials have inspired the exploration of novel materials from protein building blocks. The ability of proteins to self-organize into amyloid-like nanofibrils has opened an avenue to new materials by hierarchical assembly processes. As the mechanisms by which proteins form nanofibrils are becoming clear, the challenge now is to understand how the nanofibrils can be designed to form larger structures with defined order. We here report the spontaneous and reproducible formation of ordered microstructure in solution cast films from whey protein nanofibrils. The structural features are directly connected to the nanostructure of the protein fibrils, which is itself determined by the molecular structure of the building blocks. Hence, a hierarchical assembly process ranging over more than six orders of magnitude in size is described. The fibril length distribution is found to be the main determinant of the microstructure and the assembly process originates in restricted capillary flow induced by the solvent evaporation. We demonstrate that the structural features can be switched on and off by controlling the length distribution or the evaporation rate without losing the functional properties of the protein nanofibrils
Heterotic M-Theory Cosmology in Four and Five Dimensions
We study rolling radii solutions in the context of the four- and
five-dimensional effective actions of heterotic M-theory. For the standard
four-dimensional solutions with varying dilaton and T-modulus, we find
approximate five-dimensional counterparts. These are new, generically
non-separating solutions corresponding to a pair of five-dimensional domain
walls evolving in time. Loop corrections in the four-dimensional theory are
described by certain excitations of fields in the fifth dimension. We point out
that the two exact separable solutions previously discovered are precisely the
special cases for which the loop corrections are time-independent. Generically,
loop corrections vary with time. Moreover, for a subset of solutions they
increase in time, evolving into complicated, non-separating solutions. In this
paper we compute these solutions to leading, non-trivial order. Using the
equations for the induced brane metric, we present a general argument showing
that the accelerating backgrounds of this type cannot evolve smoothly into
decelerating backgrounds.Comment: 15 pages, Latex, 1 eps figur
First escaping fast ion mesurements in ITER-like geometry using an activation probe
More research is needed to develop suitable diagnostics for measuring alpha particle confinement in ITER and techniques relevant for fusion reactor conditions need further development. Based on nuclear reactions, the activation probe is a novel concept first tested in JET. It may offer a more robust solution for performing alpha particle measurements in ITER. This paper describes the first escaping fast ion measurements performed at ASDEX Upgrade (AUG) tokamak using an activation probe. A detailed analysis, outside the scope of this contribution, will be published in a journal paper.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard
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