1,558 research outputs found
Design of a "Digital Atlas Vme Electronics" (DAVE) Module
ATLAS-SCT has developed a new ATLAS trigger card, 'Digital Atlas Vme
Electronics' ("DAVE"). The unit is designed to provide a versatile array of
interface and logic resources, including a large FPGA. It interfaces to both
VME bus and USB hosts. DAVE aims to provide exact ATLAS CTP (ATLAS Central
Trigger Processor) functionality, with random trigger, simple and complex
deadtime, ECR (Event Counter Reset), BCR (Bunch Counter Reset) etc. being
generated to give exactly the same conditions in standalone running as
experienced in combined runs. DAVE provides additional hardware and a large
amount of free firmware resource to allow users to add or change functionality.
The combination of the large number of individually programmable inputs and
outputs in various formats, with very large external RAM and other components
all connected to the FPGA, also makes DAVE a powerful and versatile FPGA
utility cardComment: 8 pages, 4 figures, TWEPP-2011; E-mail: [email protected]
The DSM-5 dissociative-PTSD subtype: Can levels of depression, anxiety, hostility, and sleeping difficulties differentiate between dissociative-PTSD and PTSD in rape and sexual assault victims?
From Lagrangians to Events: Computer Tutorial at the MC4BSM-2012 Workshop
This is a written account of the computer tutorial offered at the Sixth
MC4BSM workshop at Cornell University, March 22-24, 2012. The tools covered
during the tutorial include: FeynRules, LanHEP, MadGraph, CalcHEP, Pythia 8,
Herwig++, and Sherpa. In the tutorial, we specify a simple extension of the
Standard Model, at the level of a Lagrangian. The software tools are then used
to automatically generate a set of Feynman rules, compute the invariant matrix
element for a sample process, and generate both parton-level and fully
hadronized/showered Monte Carlo event samples. The tutorial is designed to be
self-paced, and detailed instructions for all steps are included in this
write-up. Installation instructions for each tool on a variety of popular
platforms are also provided.Comment: 58 pages, 1 figur
Assessing a five factor model of PTSD: Is dysphoric arousal a unique PTSD construct showing differential relationships with anxiety and depression?
Posttraumatic stress disorder\u27s (PTSD) latent structure has been widely debated. To date, two four-factor models (Numbing and Dysphoria) have received the majority of factor analytic support. Recently, Elhai et al. (2011) proposed and supported a revised (five-factor) Dysphoric Arousal model. Data were gathered from two separate samples; War veterans and Primary Care medical patients. The three models were compared and the resultant factors of the Dysphoric Arousal model were validated against external constructs of depression and anxiety. The Dysphoric Arousal model provided significantly better fit than the Numbing and Dysphoria models across both samples. When differentiating between factors, the current results support the idea that Dysphoric Arousal can be differentiated from Anxious Arousal but not from Emotional Numbing when correlated with depression. In conclusion, the Dysphoria model may be a more parsimonious representation of PTSD\u27s latent structure in these trauma populations despite superior fit of the Dysphoric Arousal model
The Octant Module of the ATLAS Level-1 Muon to Central Trigger Processor Interface
The Muon to Central Trigger Processor Interface (MUCTPI) of the ATLAS Level-1 trigger receives data from the sector logic modules of the muon trigger at every bunch crossing and calculates the total multiplicity of muon candidates, which is then sent to the Central Trigger Processor where the final Level-1 decision is taken. The MUCTPI system consists of a 9U VME crate with a special backplane and 18 custom designed modules. We focus on the design and implementation of the octant module (MIOCT). Each of the 16 MIOCT modules processes the muon candidates from 13 sectors of one half-octant of the detector and forms the local muon candidate multiplicities for the trigger decision. It also resolves the overlaps between chambers in order to avoid double-counting of muon candidates that are detected in more than one sector. The handling of overlapping sectors is based on Look-Up-Tables (LUT) for maximum flexibility. The MIOCT also sends the information on the muon candidates over the custom backplane via the Readout Driver module to the Level-2 trigger and the DAQ systems when a Level-1 Accept is received. The design is based on state-of-the-art FPGA devices and special attention was paid to low-latency in the data transmission and processing
Hadron beam test of a scintillating fibre tracker system for elastic scattering and luminosity measurement in ATLAS
A scintillating fibre tracker is proposed to measure elastic proton
scattering at very small angles in the ATLAS experiment at CERN. The tracker
will be located in so-called Roman Pot units at a distance of 240 m on each
side of the ATLAS interaction point. An initial validation of the design
choices was achieved in a beam test at DESY in a relatively low energy electron
beam and using slow off-the-shelf electronics. Here we report on the results
from a second beam test experiment carried out at CERN, where new detector
prototypes were tested in a high energy hadron beam, using the first version of
the custom designed front-end electronics. The results show an adequate
tracking performance under conditions which are similar to the situation at the
LHC. In addition, the alignment method using so-called overlap detectors was
studied and shown to have the expected precision.Comment: 12 pages, 8 figures. Submitted to Journal of Instrumentation (JINST
Study of Higgs boson production and its b-bbar decay in gamma-gamma processes in proton-nucleus collisions at the LHC
We explore for the first time the possibilities to measure an
intermediate-mass (mH = 115-140 GeV/c^2) Standard-Model Higgs boson in
electromagnetic proton-lead (pPb) interactions at the CERN Large Hadron
Collider (LHC) via its b-bbar decay. Using equivalent Weizsaecker-Williams
photon fluxes and Higgs effective field theory for the coupling gamma-gamma -->
H, we obtain a leading-order cross section of the order of 0.3 pb for exclusive
Higgs production in elastic (pPb --> gamma-gamma --> p H Pb) and semielastic
(pPb --> gamma-gamma --> Pb H X) processes at sqrt(s) = 8.8 TeV. After applying
various kinematics cuts to remove the main backgrounds (gamma-gamma --> b-bbar
and misidentified gamma-gamma-->q-qbar events), we find that a Higgs boson with
mH = 120 GeV/c^2 could be observed in the b-bbar channel with a
3sigma-significance integrating 300 pb^-1 with an upgraded pA luminosity of
10^31 cm^-2s^-1. We also provide for the first time semielastic Higgs cross
sections, along with elastic t-tbar cross sections, for electromagnetic pp, pA
and AA collisions at the LHC.Comment: 22 pages, 8 figures. Tiny changes. Version as publishe
Soil methane sink capacity response to a long-term wildfire chronosequence in Northern Sweden
Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished
The ATLAS level-1 Central Trigger
The ATLAS Level-1 Central Trigger consists of the Muon-to-Central-Trigger-Processor Interface (MUCTPI), the Central Trigger Processor (CTP), and the Timing, Trigger and Control (TTC) partitions of the sub-detectors. The MUCTPI connects the output of the muon trigger system to the CTP. At every bunch crossing it receives information on muon candidates from each of the 208 muon trigger sectors and calculates the total multiplicity for each of six pT thresholds. The CTP combines information from the calorimeter trigger and the MUCTPI and makes the final Level-1 Accept (L1A) decision on the basis of lists of selection criteria (trigger menus). The MUCTPI and the CTP provide trigger summary information to the Level-2 trigger and to the data acquisition (DAQ) for every event selected at the Level-1. They further provide accumulated and, for the CTP, bunch-by-bunch counter data for monitoring of the trigger, detector and beam conditions. The TTC partitions send timing, trigger and control signals from the CTP to the sub-detectors and receive busy signals which can throttle the generation of L1As. The Local Trigger Processors (LTPs) normally receive the TTC signals from the CTP but can also generate them locally. The LTP interface (LTPIM) modules allow connecting of several LTPs for combined local running. The MUCTPI, the CTP and most of the TTC partitions of the ATLAS sub-detectors have been installed in the ATLAS experiment and are being used for commissioning tests with the trigger processors on the input and several sub-detectors as well as DAQ and Level-2 trigger on the output. Results of operating the Central Trigger in the experiment using trigger information from trigger processors connected to subdetectors observing cosmic rays will be shown
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