The LHCb trigger system Head, T
Journal of instrumentation,
09/2014, Volume:
9, Issue:
9
Journal Article
Peer reviewed
Open access
The LHCb experiment is dedicated to the study of particles containing b or c quarks at the LHC. The LHCb trigger system plays a key role in selecting signal events and rejecting background. It ...consists of two stages: a hardware trigger followed by a high-level trigger implemented in software. The majority of the work is performed by the high level trigger. With its flexible design, the LHCb trigger can quickly adapt to changing running conditions and has performed far beyond its design in terms of signal efficiencies. The trigger system showcases a number of pioneering concepts, among them the use of multivariate classifiers to identify b-hadrons and the buffering of events to local disks and their processing at a later time, when the LHC is not producing collisions. The design of the trigger system, its performance during 2011/2012 and improvements for data taking in 2015 are discussed. The redesign of the trigger system for the upgrade of the LHCb experiment in 2018 is outlined.
We explore the internal structure of red-sequence galaxies in the Coma cluster across a wide range of luminosities (−17 > M
g
> −22) and cluster-centric radii (0 < r
cluster < 1.3 r
200). We present ...the 2D bulge-disc decomposition of galaxies in deep Canada-France-Hawaii Telescope u, g, i imaging using galfit. Rigorous filtering is applied to identify an analysis sample of 200 galaxies which are well described by an 'archetypal' S0 structure (central bulge + outer disc). We consider internal bulge and/or disc colour gradients by allowing component sizes to vary between bands. Gradients are required for 30 per cent of analysis sample galaxies. Bulge half-light radii are found to be uncorrelated with galaxy luminosity (R
e ∼ 1 kpc, n ∼ 2) for all but the brightest galaxies (M
g
< −20.5). The S0 discs are brighter (at fixed size, or smaller at fixed luminosity) than those of star-forming spirals. A similar colour-magnitude relation is found for both bulges and discs. The global red sequence for S0s in Coma hence results from a combination of both component trends. We measure an average bulge - disc colour difference of 0.09 ± 0.01 mag in g − i, and 0.16 ± 0.01 mag in u − g. Using simple stellar population models, bulges are either ∼2-3 times older, or ∼ 2 times more metal rich than discs. The trend towards bluer global S0 colours observed further from Coma's core is driven by a significant correlation in disc colour with cluster-centric radius. An equivalent trend is detected in bulge colours at a marginal significance level. Our results therefore favour environment-mediated mechanisms of disc fading as the dominant factor in S0 formation.
Upgrades to the LHCb computing infrastructure in the first long shutdown of the LHC have allowed for high quality decay information to be calculated by the software trigger making a separate offline ...event reconstruction unnecessary. Furthermore, the storage space of the triggered candidate is an order of magnitude smaller than the entire raw event that would otherwise need to be persisted. Tesla is an application designed to process the information calculated by the trigger, with the resulting output used to directly perform physics measurements.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We investigate a mathematical model of tumor–immune interactions with chemotherapy, and strategies for optimally administering treatment. In this paper we analyze the dynamics of this model, ...characterize the optimal controls related to drug therapy, and discuss numerical results of the optimal strategies. The form of the model allows us to test and compare various optimal control strategies, including a quadratic control, a linear control, and a state-constraint. We establish the existence of the optimal control, and solve for the control in both the quadratic and linear case. In the linear control case, we show that we cannot rule out the possibility of a singular control. An interesting aspect of this paper is that we provide a graphical representation of regions on which the singular control is optimal.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Sacrococcygeal teratomas (SCT) are rarely seen in neonatal period. The primary treatment is surgical resection. Stabilizing these infants preoperatively and intraoperatively has posed a challenge to ...pediatric specialists. The most common complications of prenatally diagnosed SCTs are high-output heart failure, tumor rupture causing hemorrhaging, and electrolyte abnormalities. Severe hyperkalemia can be lethal. We present a case where typical medical management of hyperkalemia was unsuccessful and emergent decision had to be made to perform exchange transfusion while infant was undergoing surgical resection with a good outcome.
•Prompt hyperkalemia management is crucial to prevent cardiac arrest.•Though tumor lysis syndrome is rarely seen in neonatal intensive care units, it should still be on the differential diagnosis for hyperkalemia.•Consider exchange transfusion during surgical resection of SCT when hyperkalemia is refractory to medical management.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Modern science clearly demands for a higher level of reproducibility and collaboration. To make research fully reproducible one has to take care of several aspects: research protocol description, ...data access, environment preservation, workflow pipeline, and analysis script preservation. Version control systems like git help with the workflow and analysis scripts part. Virtualization techniques like Docker or Vagrant can help deal with environments. Jupyter notebooks are a powerful platform for conducting research in a collaborative manner. We present project Everware that seamlessly integrates git repository management systems such as Github or Gitlab, Docker and Jupyter helping with a) sharing results of real research and b) boosts education activities. With the help of Everware one can not only share the final artifacts of research but all the depth of the research process. This been shown to be extremely helpful during organization of several data analysis hackathons and machine learning schools. Using Everware participants could start from an existing solution instead of starting from scratch. They could start contributing immediately. Everware allows its users to make use of their own computational resources to run the workflows they are interested in, which leads to higher scalability of the toolkit.
Post-operative pericardial adhesions remain a serious complication after cardiac surgery that can lead to increased morbidity and mortality. Fibrous adhesions can destroy tissue planes leading to ...injury of surrounding vasculature, lengthening of operation time, and increased healthcare costs. While animal models are necessary for studying the formation and prevention of post-operative pericardial adhesions, a standardized animal model for inducing post-operative pericardial adhesions has not yet been established. In order to address this barrier to progress, an analysis of the literature on animal models for post-operative pericardial adhesions was performed. The animal model, method used to induce adhesions, and the time to allow development of adhesions were analyzed. Our analysis found that introduction of autologous blood into the pericardial cavity in addition to physical abrasion of the epicardium caused more severe adhesion formation in comparison to abrasion alone or abrasion with desiccation (vs. abrasion alone
p
= 0.0002; vs. abrasion and desiccation
p
= 0.0184). The most common time frame allowed for adhesion formation was 2 weeks, with the shortest time being 10 days and the longest being 12 months. Finally, we found that the difference in adhesion severity in all animal species was similar, suggesting the major determinants for the choice of model are animal size, animal cost, and the availability of research tools in the particular model. This survey of the literature provides a rational guide for researchers to select the appropriate adhesion induction modality, animal model, and time allowed for the development of adhesions.
We present deep Gemini Multi-Object Spectrograph long-slit spectroscopy of 15 Coma cluster S0 galaxies, and extract kinematic properties along the major axis to several times the disc scalelength. ...Supplementing our data set with previously published data, we create a combined sample of 29 Coma S0s, as well as a comparison sample of 38 Coma spirals. Using photometry from the Sloan Digital Sky Survey and Two Micron All Sky Survey, we construct the Tully-Fisher relation (TFR; luminosity versus maximum rotational velocity) for S0 galaxies. At fixed rotational velocity, the Coma S0 galaxies are on average fainter than Coma spirals by 1.10 ± 0.18, 0.86 ± 0.19 and 0.83 ± 0.19 mag in the g, i and K
s bands, respectively. The typical S0 offsets remain unchanged when calculated relative to large field-galaxy spiral samples. The observed offsets are consistent with a simple star formation model in which S0s are identical to spirals until abrupt quenching occurs at some intermediate redshift. The offsets form a continuous distribution tracing the time since the cessation of star formation, and exhibit a strong correlation (>6σ) with residuals from the optical colour-magnitude relation. Typically, S0s which are fainter than average for their rotational velocity are also redder than average for their luminosity. The S0 TFR offset is also correlated with both the projected cluster-centric radius and the Σ (projected) local density parameter. Since current local environment is correlated with time of accretion into the cluster, our results support a scenario in which transformation of spirals to S0s is triggered by cluster infall.
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