671 research outputs found
Herwig++ 2.0 Release Note
A new release of the Monte Carlo program Herwig++ (version 2.0) is now
available. This is the first version of the program which can be used for
hadron-hadron physics and includes the full simulation of both initial- and
final-state QCD radiation.Comment: Source code and additional information available at
http://hepforge.cedar.ac.uk/herwig
Herwig++1.0: an event generator for e(+)e(-) annihilation
Results from the new Monte Carlo event generator Herwig++ are presented. This
first version simulates Hadron Emission Reactions With Interfering Gluons in
electron-positron annihilation. The parton shower evolution is carried out
using new evolution variables suited to describing radiation from heavy quarks
as well as light partons. The partonic final state is fragmented into hadrons
by means of an improved cluster hadronization model. The results are compared
with a wide variety of data from LEP and SLC
Gel mobility shift scanning of pectin-inducible promoter from Penicillium griseoroseum reveals the involvement of a CCAAT element in the expression of a polygalacturonase gene
Previous reports have described pgg2, a polygalacturonase-encoding gene of Penicillium griseoroseum, as an attractive model for transcriptional regulation studies, due to its high expression throughout several in vitro growth conditions, even in the presence of non-inducing sugars such as sucrose. A search for regulatory motifs in the 5' upstream regulatory sequence of pgg2 identified a putative CCAAT box that could justify this expression profile. This element, located 270 bp upstream of the translational start codon, was tested as binding target for regulatory proteins. Analysis of a 170 bp promoter fragment by electrophoretic mobility shift assay (EMSA) with nuclear extracts prepared from mycelia grown in pectin-containing culture medium revealed a high mobility complex that was subsequently confirmed by analyzing it with a double-stranded oligonucleotide spanning the CCAAT motif. A substitution in the core sequence for GTAGG partially abolished the formation of specific complexes, showing the involvement of the CCAAT box in the regulation of the polygalacturonase gene studied
CAP defines a second signalling pathway required for insulin-stimulated glucose transport
Insulin stimulates the transport of glucose into fat and muscle cells. Although the precise molecular mechanisms involved in this process remain uncertain, insulin initiates its actions by binding to its tyrosine kinase receptor, leading to the phosphorylation of intracellular substrates. One such substrate is the Cbl protooncogene product(1). Cbl is recruited to the insulin receptor by interaction with the adapter protein CAP, through one of three adjacent SH3 domains in the carboxy terminus of CAP(2). Upon phosphorylation of Cbl, the CAP-Cbl complex dissociates from the insulin receptor and moves to a caveolin-enriched, triton-insoluble membrane fraction(3). Here, to identify a molecular mechanism underlying this subcellular redistribution, we screened a yeast two-hybrid library using the amino-terminal region of CAP and identified the caveolar protein flotillin. Flotillin forms a ternary complex with CAP and Cbl, directing the localization of the CAP-Cbl complex to a lipid raft subdomain of the plasma membrane. Expression of the N-terminal domain of CAP in 3T3-L1 adipocytes blocks the stimulation of glucose transport by insulin, without affecting signalling events that depend on phosphatidylinositol-3-OH kinase. Thus, localization of the Cbl-CAP complex to lipid rafts generates a pathway that is crucial in the regulation of glucose uptake.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62940/1/407202a0.pd
GeantV: Results from the prototype of concurrent vector particle transport simulation in HEP
Full detector simulation was among the largest CPU consumer in all CERN
experiment software stacks for the first two runs of the Large Hadron Collider
(LHC). In the early 2010's, the projections were that simulation demands would
scale linearly with luminosity increase, compensated only partially by an
increase of computing resources. The extension of fast simulation approaches to
more use cases, covering a larger fraction of the simulation budget, is only
part of the solution due to intrinsic precision limitations. The remainder
corresponds to speeding-up the simulation software by several factors, which is
out of reach using simple optimizations on the current code base. In this
context, the GeantV R&D project was launched, aiming to redesign the legacy
particle transport codes in order to make them benefit from fine-grained
parallelism features such as vectorization, but also from increased code and
data locality. This paper presents extensively the results and achievements of
this R&D, as well as the conclusions and lessons learnt from the beta
prototype.Comment: 34 pages, 26 figures, 24 table
INFLUENCE OF TIME MANAGEMENT IN MODELING OF CURVE RESISTANCE TO THE PENETRATION OF A LATOSOL UNDER DIFFERENT USES AND MANAGEMENT OF PASTURES AND NATIVE WOODLAND
Offloading electromagnetic shower transport to GPUs
Making general particle transport simulation for high-energy physics (HEP)
single-instruction-multiple-thread (SIMT) friendly, to take advantage of
accelerator hardware, is an important alternative for boosting the throughput
of simulation applications. To date, this challenge is not yet resolved, due to
difficulties in mapping the complexity of Geant4 components and workflow to the
massive parallelism features exposed by graphics processing units (GPU). The
AdePT project is one of the R\&D initiatives tackling this limitation and
exploring GPUs as potential accelerators for offloading some part of the CPU
simulation workload. Our main target is to implement a complete electromagnetic
shower demonstrator working on the GPU. The project is the first to create a
full prototype of a realistic electron, positron, and gamma electromagnetic
shower simulation on GPU, implemented as either a standalone application or as
an extension of the standard Geant4 CPU workflow. Our prototype currently
provides a platform to explore many optimisations and different approaches. We
present the most recent results and initial conclusions of our work, using both
a standalone GPU performance analysis and a first implementation of a hybrid
workflow based on Geant4 on the CPU and AdePT on the GPU.Comment: 8 pages, 4 figures, 20th International Workshop on Advanced Computing
and Analysis Techniques in Physics Research (ACAT 2021), to be published in
Journal of Physics: Conference Series, editor Andrei Gheat
Shower development of particles with momenta from 15 GeV to 150 GeV in the CALICE scintillator-tungsten hadronic calorimeter
We present a study of showers initiated by electrons, pions, kaons, and
protons with momenta from 15 GeV to 150 GeV in the highly granular CALICE
scintillator-tungsten analogue hadronic calorimeter. The data were recorded at
the CERN Super Proton Synchrotron in 2011. The analysis includes measurements
of the calorimeter response to each particle type as well as measurements of
the energy resolution and studies of the longitudinal and radial shower
development for selected particles. The results are compared to Geant4
simulations (version 9.6.p02). In the study of the energy resolution we include
previously published data with beam momenta from 1 GeV to 10 GeV recorded at
the CERN Proton Synchrotron in 2010.Comment: 35 pages, 21 figures, 8 table
Observation of Hadronic W Decays in t-tbar Events with the Collider Detector at Fermilab
We observe hadronic W decays in t-tbar -> W (-> l nu) + >= 4 jet events using
a 109 pb-1 data sample of p-pbar collisions at sqrt{s} = 1.8 TeV collected with
the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass
distribution is obtained that is consistent with W decay and inconsistent with
the background prediction by 3.3 standard deviations. From this peak we measure
the W mass to be 77.2 +- 4.6 (stat+syst) GeV/c^2. This result demonstrates the
presence of two W bosons in t-tbar candidates in the W (-> l nu) + >= 4 jet
channel.Comment: 20 pages, 4 figures, submitted to PR
The Time Structure of Hadronic Showers in highly granular Calorimeters with Tungsten and Steel Absorbers
The intrinsic time structure of hadronic showers influences the timing
capability and the required integration time of hadronic calorimeters in
particle physics experiments, and depends on the active medium and on the
absorber of the calorimeter. With the CALICE T3B experiment, a setup of 15
small plastic scintillator tiles read out with Silicon Photomultipliers, the
time structure of showers is measured on a statistical basis with high spatial
and temporal resolution in sampling calorimeters with tungsten and steel
absorbers. The results are compared to GEANT4 (version 9.4 patch 03)
simulations with different hadronic physics models. These comparisons
demonstrate the importance of using high precision treatment of low-energy
neutrons for tungsten absorbers, while an overall good agreement between data
and simulations for all considered models is observed for steel.Comment: 24 pages including author list, 9 figures, published in JINS
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