Abstract
High energy physics experiments, in particular experiments
at the LHC, require the reconstruction of charged particle
trajectories. Methods of reconstructing such trajectories have been
...known for decades, yet the applications at High Luminosity LHC
require this reconstruction to be fast enough to be suitable for
online event filtering.
A particle traversing the detector volume leaves signals in active
detector elements from which the trajectory is reconstructed. If the
detector is submerged in a uniform magnetic field that trajectory is
approximately helical. Since a collision event results in the
production of many particles, especially at high luminosities, the
first phase of trajectory reconstruction is the formation of
candidate trajectories composed of a small subset of detector
measurements that are then subject of resource intensive precise
track parameters estimation.
In this paper, we suggest a new approach that could be used to
perform this classification. The proposed procedure utilizes the
z
coordinate in the longitudinal direction in addition to the
x
,
y
coordinates in the plane perpendicular to the direction of the
magnetic field. The suggested algorithm works equally well for
helical trajectories with different proximities to the beamline
which is beneficial when searching for products of particles with
longer lifetimes.
Aneuploidy is a consequence of chromosomal instability (CIN) that affects prognosis. Gene expression levels associated with aneuploidy provide insight into the molecular mechanisms underlying CIN. ...Based on the gene signature whose expression was consistent with functional aneuploidy, the CIN70 score was established. We observed an association of CIN70 score and survival in 519 HNSCC patients in the TCGA dataset; the 15% patients with the lowest CIN70 score showed better survival (
= 0.11), but association was statistically non-significant. This correlated with the expression of 39 proteins of the major repair complexes. A positive association with survival was observed for MSH2, XRCC1, MRE11A, BRCA1, BRCA2, LIG1, DNA2, POLD1, MCM2, RAD54B, claspin, a negative for ERCC1, all related with replication. We hypothesized that expression of these factors leads to protection of replication through efficient repair and determines survival and resistance to therapy. Protein expression differences in HNSCC cell lines did not correlate with cellular sensitivity after treatment. Rather, it was observed that the stability of the DNA replication fork determined resistance, which was dependent on the ATR/CHK1-mediated S-phase signaling cascade. This suggests that it is not the expression of individual DNA repair proteins that causes therapy resistance, but rather a balanced expression and coordinated activation of corresponding signaling cascades.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Measurement of the luminosity in the ZEUS experiment at HERA II Adamczyk, L.; Andruszkow, J.; Bold, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2014, Volume:
744
Journal Article
Peer reviewed
Open access
The luminosity in the ZEUS detector was measured using photons from electron bremsstrahlung off protons. In 2001 the HERA collider was upgraded for operation at higher luminosity. At the same time ...the luminosity-measuring system of the ZEUS experiment was modified to tackle the expected higher photon rate and synchrotron radiation. The existing lead-scintillator calorimeter was equipped with radiation hard scintillator tiles and shielded against synchrotron radiation. In addition, a magnetic spectrometer was installed to measure the luminosity independently using photons converted in the beam-pipe exit window. The redundancy provided a reliable and robust luminosity determination with a systematic uncertainty of 1.7%. The experimental setup, the techniques used for luminosity determination and the estimate of the systematic uncertainty are reported.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
ATLAS's current software framework, Gaudi Athena, has been very successful for the experiment in LHC Runs 1 and 2. However, its single-threaded design has been recognised for some time to be ...increasingly problematic as CPUs have increased core counts and decreased available memory per core. Even the multi-process version of Athena, AthenaMP, will not scale to the range of architectures we expect to use beyond Run2. ATLAS examined the requirements on an updated multi-threaded framework and laid out plans for a new framework, including better support for High Level Trigger use cases, in 2014. In this paper we report on our progress in developing the new multi-threaded task parallel extension of Athena, AthenaMT. Implementing AthenaMT has required many significant code changes. Progress has been made in updating key concepts of the framework, allowing different levels of thread safety in algorithmic code. Substantial advances have also been made in implementing a data flow centric design, as well as on the development of the new 'event views' infrastructure. These event views support partial event processing and are an essential component to support the High Level Trigger's processing of certain regions of interest. A major effort has also been invested to have an early version of AthenaMT that can run simulation on many core architectures, which has augmented the understanding gained from work on earlier ATLAS demonstrators.
Sixty two infants <28 weeks were occlusively wrapped and randomised to radiant warmer or incubator transport to the neonatal unit. Median axillary temperature on arrival was 36.8°C in both groups. ...Target temperatures (36.5–37.5°C) were achieved in 60% of the incubator group compared to 75% in the warmer group (not statistically significant). While powered to detect a 35% difference between warming devices, a more modest difference is not excluded.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
8.
Triggering events with GPUs at ATLAS Kama, S; Soares, J Augusto; Baines, J ...
Journal of physics. Conference series,
01/2015, Volume:
664, Issue:
9
Journal Article
Peer reviewed
Open access
The growing complexity of events produced in LHC collisions demands increasing computing power both for the online selection and for the offline reconstruction of events. In recent years there have ...been significant advances in the performance of Graphics Processing Units (GPUs) both in terms of increased compute power and reduced power consumption that make GPUs extremely attractive for use in a complex particle physics experiments such as ATLAS. A small scale prototype of the full ATLAS High Level Trigger has been implemented that exploits reconstruction algorithms optimized for this new massively parallel paradigm. We discuss the integration procedure followed for this prototype and present the performance achieved and the prospects for the future.
The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of efficiently selecting interesting candidate events in pp collisions at 14 TeV centre-of-mass energy, whilst ...rejecting the enormous number of background events. The High-Level-Trigger (HLT second level trigger and Event Filter), which is a software based trigger will need to reduce the first level trigger output rate of kHz to Hz written out to mass storage. In this paper an overview of the steering mechanism of the HLT is given. The HLT Steering is responsible for the scheduling of algorithms and for the global event trigger decision evaluation. The concept of step-wise and seeded selection strategy implemented by the steering will be presented. Integration of large number of trigger menus and sophisticated physics selection strategies will also be discussed. The electron and photon menus will be described to demonstrate that the trigger is well adapted for the physics program at the LHC.
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