121 research outputs found
Validation of Observed Bedload Transport Pathways Using Morphodynamic Modeling
Phenomena related to braiding, including local scour and fill, channel bar development, migration
and avulsion, make numerical morphodynamic modeling of braided rivers challenging. This paper investigates
the performance of a Delft3D model, in a 2D depth-averaged formulation, to simulate the
morphodynamics of an anabranch of the Rees River (New Zealand). Model performance is evaluated using
data from field surveys collected on the falling limb of a major high flow, and using several sediment
transport formulas. Initial model results suggest that there is generally good agreement between observed and
modeled bed levels. However, some discrepancies in the bed level estimations were noticed, leading to bed
level, water depth and water velocity estimation errors
A Model for the Stray Light Contamination of the UVCS Instrument on SOHO
We present a detailed model of stray-light suppression in the spectrometer
channels of the Ultraviolet Coronagraph Spectrometer (UVCS) on the SOHO
spacecraft. The control of diffracted and scattered stray light from the bright
solar disk is one of the most important tasks of a coronagraph. We compute the
fractions of light that diffract past the UVCS external occulter and
non-specularly pass into the spectrometer slit. The diffracted component of the
stray light depends on the finite aperture of the primary mirror and on its
figure. The amount of non-specular scattering depends mainly on the
micro-roughness of the mirror. For reasonable choices of these quantities, the
modeled stray-light fraction agrees well with measurements of stray light made
both in the laboratory and during the UVCS mission. The models were constructed
for the bright H I Lyman alpha emission line, but they are applicable to other
spectral lines as well.Comment: 19 pages, 5 figures, Solar Physics, in pres
Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays
Average charged multiplicities have been measured separately in , and
light quark () events from decays measured in the SLD experiment.
Impact parameters of charged tracks were used to select enriched samples of
and light quark events, and reconstructed charmed mesons were used to select
quark events. We measured the charged multiplicities:
,
, from
which we derived the differences between the total average charged
multiplicities of or quark events and light quark events: and . We compared
these measurements with those at lower center-of-mass energies and with
perturbative QCD predictions. These combined results are in agreement with the
QCD expectations and disfavor the hypothesis of flavor-independent
fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters
Comparison of two methods of tear sampling for protein quantification by Bradford method
A Compact Dication Source for Ba Tagging and Heavy Metal Ion Sensor Development
We present a tunable metal ion beam that delivers controllable ion currents
in the picoamp range for testing of dry-phase ion sensors. Ion beams are formed
by sequential atomic evaporation and single or multiple electron impact
ionization, followed by acceleration into a sensing region. Controllability of
the ionic charge state is achieved through tuning of electrode potentials that
influence the retention time in the ionization region. Barium, lead, and cobalt
samples have been used to test the system, with ion currents identified and
quantified using a quadrupole mass analyzer. Realization of a clean
ion beam within a bench-top system represents an important
technical advance toward the development and characterization of barium tagging
systems for neutrinoless double beta decay searches in xenon gas. This system
also provides a testbed for investigation of novel ion sensing methodologies
for environmental assay applications, with dication beams of Pb and
Cd also demonstrated for this purpose
Planck early results. VI. The High Frequency Instrument data processing
We describe the processing of the 336 billion raw data samples from the High Frequency Instrument (HFI) which we performed to produce six
temperature maps from the first 295 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143,
217, 353, 545 and 857GHz with an angular resolution ranging from 9.9 to 4.4 . The white noise level is around 1.5 μK degree or less in the 3 main
CMB channels (100–217 GHz). The photometric accuracy is better than 2% at frequencies between 100 and 353 GHz and around 7% at the two
highest frequencies. The maps created by the HFI Data Processing Centre reach our goals in terms of sensitivity, resolution, and photometric
accuracy. They are already sufficiently accurate and well-characterised to allow scientific analyses which are presented in an accompanying series
of early papers. At this stage, HFI data appears to be of high quality and we expect that with further refinements of the data processing we should
be able to achieve, or exceed, the science goals of the Planck project
Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel
A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved
Comportamento ingestivo de cabras Alpinas em lactação alimentadas com dietas contendo diferentes níveis de fibra em detergente neutro proveniente da forragem
Design and construction of the MicroBooNE detector
This paper describes the design and construction of the MicroBooNE liquid
argon time projection chamber and associated systems. MicroBooNE is the first
phase of the Short Baseline Neutrino program, located at Fermilab, and will
utilize the capabilities of liquid argon detectors to examine a rich assortment
of physics topics. In this document details of design specifications, assembly
procedures, and acceptance tests are reported
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