724 research outputs found
PLENARY PANEL: A 360-DEGREE VIEW OF SCIENCE AND AGRICULTURAL POLICY; EDITED TRANSCRIPT
Agricultural and Food Policy,
Nuclear Propelled Vessels and Neutrino Oscillation Experiments
We study the effect of naval nuclear reactors on the study of neutrino
oscillations. We find that the presence of naval reactors at unknown locations
and times may limit the accuracy of future very long baseline reactor-based
neutrino oscillation experiments. At the same time we argue that a nuclear
powered surface ship such as a large Russian ice-breaker may provide an ideal
source for precision experiments. While the relatively low reactor power would
in this case require a larger detector, the source could be conveniently
located at essentially any distance from a detector built at an underground
location near a shore in a region of the world far away from other nuclear
installations. The variable baseline would allow for a precise measurement of
backgrounds and greatly reduced systematics from reactor flux and detector
efficiency. In addition, once the oscillation measurement is completed, the
detector could perform geological neutrino and astrophysical measurements with
minimal reactor background.Comment: 4 pages, 2 figure
A Generic Surface Sampler for Monte Carlo Simulations
We present an implementation of a Monte Carlo algorithm that generates points
randomly and uniformly on a set of arbitrary surfaces. The algorithm is
completely general and only requires the geometry modeling software to provide
the intersection points of an arbitrary line with the surface being sampled. We
demonstrate the algorithm using the Geant4 Monte Carlo simulation toolkit. The
efficiency of the sampling algorithm is discussed, along with various options
in the implementation and example applications
Report on Chemical Analysis and Further Dating of Dinosaur Bones and Dinosaur Petroglypths
Much of the material in this report was presented at the 1990 ICC poster sessions. Our radiocarbon dates of dinosaur bones and the other information in this report should be alarming to the evolutionary community and should be given serious study considering our preliminary results
Renormalization group parameter evolution of the minimal supersymmetric standard model with R-parity violation
A comparison of spectra obtained using the 1-loop MSSM and 2-loop R-parity
violating MSSM renormalization group equations is presented. Influence of
higher loop corrections and R-parity violating terms is discussed. Some
numerical constraints on the R-parity violating parameters are also given.Comment: 4 pages, 1 figure, using RevTE
The MGDO software library for data analysis in Ge neutrinoless double-beta decay experiments
The GERDA and Majorana experiments will search for neutrinoless double-beta
decay of germanium-76 using isotopically enriched high-purity germanium
detectors. Although the experiments differ in conceptual design, they share
many aspects in common, and in particular will employ similar data analysis
techniques. The collaborations are jointly developing a C++ software library,
MGDO, which contains a set of data objects and interfaces to encapsulate, store
and manage physical quantities of interest, such as waveforms and high-purity
germanium detector geometries. These data objects define a common format for
persistent data, whether it is generated by Monte Carlo simulations or an
experimental apparatus, to reduce code duplication and to ease the exchange of
information between detector systems. MGDO also includes general-purpose
analysis tools that can be used for the processing of measured or simulated
digital signals. The MGDO design is based on the Object-Oriented programming
paradigm and is very flexible, allowing for easy extension and customization of
the components. The tools provided by the MGDO libraries are used by both GERDA
and Majorana.Comment: 4 pages, 1 figure, proceedings for TAUP201
Miscible displacement fronts of shear thinning fluids inside rough fractures
The miscible displacement of a shear-thinning fluid by another of same
rheological properties is studied experimentally in a transparent fracture by
an optical technique imaging relative concentration distributions. The fracture
walls have complementary self-affine geometries and are shifted laterally in
the direction perpendicular to the mean flow velocity {\bf U} : the flow field
is strongly channelized and macro dispersion controls the front structure for
P\'{e}clet numbers above a few units. The global front width increases then
linearly with time and reflects the velocity distribution between the different
channels. In contrast, at the local scale, front spreading is similar to Taylor
dispersion between plane parallel surfaces. Both dispersion mechanisms depend
strongly on the fluid rheology which shifts from Newtonian to shear-thinning
when the flow rate increases. In the latter domain, increasing the
concentration enhances the global front width but reduces both Taylor
dispersion (due to the flattening of the velocity profile in the gap of the
fracture) and the size of medium scale front structures
Measurement of the double-\beta decay half-life of ^{136}Xe with the KamLAND-Zen experiment
We present results from the KamLAND-Zen double-beta decay experiment based on
an exposure of 77.6 days with 129 kg of Xe. The measured two-neutrino
double-beta decay half-life of Xe is yr, consistent with a recent
measurement by EXO-200. We also obtain a lower limit for the neutrinoless
double-beta decay half-life, yr at 90%
confidence level (C.L.), which corresponds to almost a five-fold improvement
over previous limits.Comment: 6 pages, 4 figures. Version as published in PR
Study of electron anti-neutrinos associated with gamma-ray bursts using KamLAND
We search for electron anti-neutrinos () from long and
short-duration gamma-ray bursts~(GRBs) using data taken by the KamLAND detector
from August 2002 to June 2013. No statistically significant excess over the
background level is found. We place the tightest upper limits on
fluence from GRBs below 7 MeV and place first constraints on
the relation between luminosity and effective temperature.Comment: 16 pages and 5 figure
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