938 research outputs found
Status of the CALICE DAQ system
A data acquisition (DAQ) system is described which will be used for the next
generation of prototype calorimeters using particle flow algorithms for the
International Linear Collider (ILC). The design is sufficiently generic and
scalable such that it should have numerous applications either for ILC
detectors or elsewhere within high energy physics in general. The DAQ system
will be implemented using FPGAs and built using off-the-shelf components and
networking hardware with programmable FPGAs. The software for the DAQ system is
based on an existing framework, DOOCS, which is a server/client object-oriented
system. The design philosophy, current status of the project and its aims are
presented in this report.Comment: 4 pages, 1 figure, for the LCWS08 conference proceeding
Optimization of Computationally and I/O Intense Patterns in Electronic Structure and Machine Learning Algorithms
Development of scalable High-Performance Computing (HPC) applications is already a challenging task even in the
pre-Exascale era. Utilization of the full potential of (near-)future supercomputers will most likely require the mastery
of massively parallel heterogeneous architectures with multi-tier persistence systems, ideally in fault tolerant mode.
With the change in hardware architectures HPC applications are also widening their scope to `Big data' processing and
analytics using machine learning algorithms and neural networks. In this work, in cooperation with the INTERTWinE
FET-HPC project, we demonstrate how the GASPI (Global Address Space Programming Interface) programming model
helps to address these Exascale challenges on examples of tensor contraction, K-means and Terasort algorithms
An algorithm for calculating the Lorentz angle in silicon detectors [online]
The CMS (Compact Muon Solenoid) detector will use silicon
sensors in the harsh radiation environment of the LHC (Large
Hadron Collider) and high magnetic fields.
The drift direction of the charge carriers is aected by the
Lorentz force due to the high magnetic field. Also the resulting
radiation damage changes the properties of the drift. The CMS
silicon strip detector is read out on the p-side of the sensors,
where holes are collected, while the pixel sensors have n-side
read out, thus collecting electrons.
In this paper measurements of the Lorentz angle are reviewed.
Easy algorithms to compute the Lorentz angle are proposed.
Key words: silicon, sensors, detectors, Lorentz angle, magnetic
field, CM
Lorentz angle measurements in irradiated silicon detectors between 77 K and 300 K
Future experiments are using silicon detectors in a high
radiation environment and in high magnetic fields. The radiation
tolerance of silicon improves by cooling it to temperatures
below 180 K. At low temperatures the mobility increases, which
leads to larger de of the charge carriers by the Lorentz force.
A good knowledge of the Lorentz angle is needed for design and
operation of silicon detectors. We present measurements of the
Lorentz angle between 77 K and 300 K before and after
irradiation with a primary beam of 21 MeV protons
A new method to quantify and compare the multiple components of fitness-A study case with kelp niche partition by divergent microstage adaptations to Temperature
Point 1 Management of crops, commercialized or protected species, plagues or life-cycle evolution are subjects requiring comparisons among different demographic strategies. The simpler methods fail in relating changes in vital rates with changes in population viability whereas more complex methods lack accuracy by neglecting interactions among vital rates. Point 2 The difference between the fitness (evaluated by the population growth rate.) of two alternative demographies is decomposed into the contributions of the differences between the pair-wised vital rates and their interactions. This is achieved through a full Taylor expansion (i.e. remainder = 0) of the demographic model. The significance of each term is determined by permutation tests under the null hypothesis that all demographies come from the same pool. Point 3 An example is given with periodic demographic matrices of the microscopic haploid phase of two kelp cryptic species observed to partition their niche occupation along the Chilean coast. The method provided clear and synthetic results showing conditional differentiation of reproduction is an important driver for their differences in fitness along the latitudinal temperature gradient. But it also demonstrated that interactions among vital rates cannot be neglected as they compose a significant part of the differences between demographies. Point 4 This method allows researchers to access the effects of multiple effective changes in a life-cycle from only two experiments. Evolutionists can determine with confidence the effective causes for changes in fitness whereas population managers can determine best strategies from simpler experimental designs.CONICYT-FRENCH EMBASSADY Ph.D. gran
Temperature Effects on Gametophyte Life-History Traits and Geographic Distribution of Two Cryptic Kelp Species
A major determinant of the geographic distribution of a species is expected to be its physiological response to changing abiotic variables over its range. The range of a species often corresponds to the geographic extent of temperature regimes the organism can physiologically tolerate. Many species have very distinct life history stages that may exhibit different responses to environmental factors. In this study we emphasized the critical role of the haploid microscopic stage (gametophyte) of the life cycle to explain the difference of edge distribution of two related kelp species. Lessonia nigrescens was recently identified as two cryptic species occurring in parapatry along the Chilean coast: one located north and the other south of a biogeographic boundary at latitude 29–30°S. Six life history traits from microscopic stages were identified and estimated under five treatments of temperature in eight locations distributed along the Chilean coast in order to (1) estimate the role of temperature in the present distribution of the two cryptic L. nigrescens species, (2) compare marginal populations to central populations of the two cryptic species. In addition, we created a periodic matrix model to estimate the population growth rate (λ) at the five temperature treatments. Differential tolerance to temperature was demonstrated between the two species, with the gametophytes of the Northern species being more tolerant to higher temperatures than gametophytes from the south. Second, the two species exhibited different life history strategies with a shorter haploid phase in the Northern species contrasted with considerable vegetative growth in the Southern species haploid stage. These results provide strong ecological evidence for the differentiation process of the two cryptic species and show local adaptation of the life cycle at the range limits of the distribution. Ecological and evolutionary implications of these findings are discussed
Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions
We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe
Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC
Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe
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