40,386 research outputs found
General Mass Scheme for Jet Production in DIS
We propose a method for calculating DIS jet production cross sections in QCD
at NLO accuracy with consistent treatment of heavy quarks. The scheme relies on
the dipole subtraction method for jets, which we extend to all possible initial
state splittings with heavy partons, so that the Aivazis-Collins-Olness-Tung
massive collinear factorization scheme (ACOT) can be applied. As a first check
of the formalism we recover the ACOT result for the heavy quark structure
function using a dedicated Monte Carlo program.Comment: 6 pages, 2 figure
QCD Factorization for Semi-Inclusive Deep-Inelastic Scattering at Low Transverse Momentum
We demonstrate a factorization formula for semi-inclusive deep-inelastic
scattering with hadrons in the current fragmentation region detected at low
transverse momentum. To facilitate the factorization, we introduce the
transverse-momentum dependent parton distributions and fragmentation functions
with gauge links slightly off the light-cone, and with soft-gluon radiations
subtracted. We verify the factorization to one-loop order in perturbative
quantum chromodynamics and argue that it is valid to all orders in perturbation
theory.Comment: 28 pages, figures include
Flexible Decision Control in an Autonomous Trading Agent
An autonomous trading agent is a complex piece of software that must operate in a competitive economic environment and support a research agenda. We describe the structure of decision processes in the MinneTAC trading agent, focusing on the use of evaluators – configurable, composable modules for data analysis and prediction that are chained together at runtime to support agent decision-making. Through a set of examples, we show how this structure supports sales and procurement decisions, and how those decision processes can be modified in useful ways by changing evaluator configurations. To put this work in context, we also report on results of an informal survey of agent design approaches among the competitors in the Trading Agent Competition for Supply Chain Management (TAC SCM).autonomous trading agent;decision processes
Opacification of high temperature fibrous insulation
A study was conducted to determine the merits of adding particulate materials to silica fiber felts to increase their resistance to the passage of thermal radiation. Laboratory samples containing 5, 10, and 15 percent of chromium oxide, silicon carbide, and titanium dioxide were prepared and evaluated in accordance with ASTM C-518 thermal conductivity test method at 425 C (800 F) mean temperature. The titania particles averaging 3-4 micrometers in diameter were found to be the most effective. This was followed by a short plant run, in order to confirm the initial results on the laboratory samples. These samples were tested according to ASTM C-201 High Temperature Calorimeter from 93 C to 760 C (200 F to 1400 F) mean temperature. The ten percent by weight of titania resulted in an optimum effectiveness, and reduced the conductivity over 20% at 760 C (1400 F)
Measurements in the turbulent boundary layer at constant pressure in subsonic and supersonic flow. Part 1: Mean flow
Experiments were carried out to test the accuracy of laser Doppler instrumentation for measurement of Reynolds stresses in turbulent boundary layers in supersonic flow. Two facilities were used to study flow at constant pressure. In one facility, data were obtained on a flat plate at M sub e = 0.1, with Re theta up to 8,000. In the other, data were obtained on an adiabatic nozzle wall at M sub e = 0.6, 0.8, 1.0, 1.3, and 2.2, with Re theta = 23,000 and 40,000. The mean flow as observed using Pitot tube, Preston tube, and floating element instrumentation is described. Emphasis is on the use of similarity laws with Van Driest scaling and on the inference of the shearing stress profile and the normal velocity component from the equations of mean motion. The experimental data are tabulated
Computational Identification of Four Spliceosomal snRNAs from the Deep-Branching Eukaryote Giardia intestinalis
Funding: Marsden Fund New Zealand Allan Wilson Centre The funders had no role in study design, data collection and analysis, decision to publish, or
preparation of the manuscript.RNAs processing other RNAs is very general in eukaryotes, but is not clear to what extent it is ancestral to eukaryotes. Here
we focus on pre-mRNA splicing, one of the most important RNA-processing mechanisms in eukaryotes. In most eukaryotes
splicing is predominantly catalysed by the major spliceosome complex, which consists of five uridine-rich small nuclear
RNAs (U-snRNAs) and over 200 proteins in humans. Three major spliceosomal introns have been found experimentally in
Giardia; one Giardia U-snRNA (U5) and a number of spliceosomal proteins have also been identified. However, because of
the low sequence similarity between the Giardia ncRNAs and those of other eukaryotes, the other U-snRNAs of Giardia had
not been found. Using two computational methods, candidates for Giardia U1, U2, U4 and U6 snRNAs were identified in this
study and shown by RT-PCR to be expressed. We found that identifying a U2 candidate helped identify U6 and U4 based on
interactions between them. Secondary structural modelling of the Giardia U-snRNA candidates revealed typical features of
eukaryotic U-snRNAs. We demonstrate a successful approach to combine computational and experimental methods to
identify expected ncRNAs in a highly divergent protist genome. Our findings reinforce the conclusion that spliceosomal
small-nuclear RNAs existed in the last common ancestor of eukaryotes
Detection of hidden mineral deposits by airborne spectral analysis of forest canopies
Data from field surveys and biogeochemical tests conducted in Maine, Montana, and Washington strongly correlate with results obtained using high resolution airborne spectroradiometer which detects an anomalous spectral waveform that appears definitely associated with sulfide mineralization. The spectral region most affected by mineral stress is between 550 nm and 750 nm. Spectral variations observed in the field occur on the wings of the red chlorophyll band centered at about 690 nm. The metal-stress-induced variations on the absorption band wing are most successfully resolved in the high spectral resolution field data using a waveform analysis technique. The development of chlorophyll pigments was retarded in greenhouse plants doped with copper and zinc in the laboratory. The lowered chlorophyll production resulted in changes on the wings of the chlorophyll bands of reflectance spectra of the plants. The airborne spectroradiometer system and waveform analysis remains the most sensitive technique for biogeochemical surveys
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