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Results from a non-leptonic neural-network trigger hosted by experiment WA92, looking for beauty particle production from 350 GeV π⁻ on a Cu target, are presented. The neural trigger has been used to send on a special data stream (the Fast Stream) events to be analyzed with high priority. The non-leptonic signature uses microvertex detector data and was devised so as to enrich the fraction of events containing C3 secondary vertices (i.e, vertices having three tracks whith sum of electric charges equal to +1 or -1). The neural trigger module consists of a VME crate hosting two ETANN analog neural chips from Intel. The neural trigger operated for two continuous weeks during the WA92 1993 run. For an acceptance of 15% for C3 events, the neural trigger yields a C3 enrichment factor of 6.6–7.1 (depending on the event sample considered), which multiplied by that already provided by the standard non-leptonic trigger leads to a global C3 enrichment factor of ≈150. In the event sample selected by the neural trigger for the Fast Stream, 1 every ≈7 events contains a C3 vertex. The response time of the neural trigger module is 5.8 μs.

With the high bunch-crossing and interaction rates and potentially large event sizes, the experiments at the LHC challenge data acquisition and trigger systems. Within the ATLAS experiment, a multi-level trigger system based on hardware and software is employed to cope with the task of event-rate reduction. This review gives an overview of the trigger of the ATLAS experiment highlighting the design principles and the implementation of the system and provides references to more detailed information. In addition, first trigger-performance studies and an outlook on the ATLAS event-selection strategy are presented.

The DØ trigger system has been upgraded for Run II at the Tevatron. I present the current status of the DØ trigger.

At BABAR, the Level 1 Drift Chamber trigger is being upgraded to reduce increasing background rates while the PEP-II luminosity keeps improving. This upgrade uses the drift time information and stereo wires in the drift chamber to perform a 3D track reconstruction that effectively rejects background events spread out along the beam line.

The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) at CERN. The experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. In this paper the performance of the various LHCb sub-detectors and the trigger system are described, using data taken from 2010 to 2012. It is shown that the design criteria of the experiment have been met. The excellent performance of the detector has allowed the LHCb collaboration to publish a wide range of physics results, demonstrating LHCb's unique role, both as a heavy flavour experiment and as a general purpose detector in the forward region.

Electron and photon triggers are an important part of many physics analyses at the ATLAS experiment, where electron and photon final states are considered. Understanding the performance of electron and photon triggers at the High Level trigger as well as the Level-1 trigger was crucial to improve and adapt the trigger during changing run conditions of the Large Hadron Collider in Run 2 (2015–2018).

During Run 2 (2015–2018) the Large Hadron Collider has provided, at the World’s highest energy frontier, proton–proton collisions to the ATLAS experiment with high instantaneous luminosity (up to $2.1\times 10^{34}{\mathrm{\text{cm}}}^{-2}{\mathrm{\text{s}}}^{-1}$), placing stringent operational and physics requirements on the ATLAS trigger system in order to reduce the 40 MHz collision rate to a manageable event storage rate of 1 kHz, while not rejecting interesting collisions. The Level-1 trigger is the first rate-reducing step in the ATLAS trigger system with an output rate of up to 100 kHz and decision latency of less than 2.5 $\mu$s. In Run 2, an important role was played by the Level-1 Topological Processor (L1Topo). This innovative system consists of two blades designed in AdvancedTCA form factor, mounting four individual state-of-the-art processors, and providing high input bandwidth and low latency data processing. Up to 128 topological trigger algorithms can be implemented to select interesting events by applying kinematic and angular requirements on electromagnetic clusters, hadronic jets, muons and total energy reconstructed in the ATLAS apparatus. This resulted in a significantly improved background rejection and enhanced acceptance of physics signal events, despite the increasing luminosity. The L1Topo system has become more and more important for physics analyses making use of low energy objects, commonly present in the Heavy Flavor or Higgs physics events, for example. An overview of the L1Topo architecture, simulation and performance results during Run 2 is presented alongside with upgrade plans for the L1Topo system to be installed for the future Run 3 data taking period.

An active database system reacts to a set of external events such as a timer interrupt or access to a particular object in the database. A trigger is a general mechanism for active data management, both in the context of a centralized system or a distributed system (including that of autonomous and cooperating agents). It consists of three parts; event specification, integrity constraint specification, and action specification. The event specification in a trigger is a set of events which will cause the condition in the constraint specification to be checked. If the condition is true, the actions in the action specification will be initiated. In this paper, we develop a framework for supporting triggers in object-oriented database systems. The framework consists of a categorization for each of the three components of a trigger. The framework is first cast in the context of the relational model of data, and is then extended to account for object-oriented concepts that constitute an object-oriented data model, including nested objects, methods, and inheritance hierarchy.

Whilst the world is witnessing the impact of technology proliferation on human lives and livelihoods, the personal safety of women, though paramount, is still technologically under-addressed. This study empirically investigated the perception of Indian women ($N=$210) towards personal safety apps and their intention to accept them to ensure personal safety. This study uniquely blended the Fogg behaviour model, which comprises motives, abilities and triggers, with the Technology Acceptance Model (TAM), which comprises perceived usefulness, ease of use and behavioural intentions. Structural equation modelling using SmartPLS 4 was used to analyse the model. Some exciting outcomes emerged from this study. The motives namely subjective norms, facilitating conditions and perceived trust, significantly impacted women’s perceived usefulness of personal safety apps, while the perceived risk was insignificant. The significant impactors of women’s perceived ease-of-use of personal safety apps include the abilities of self-efficacy and technology stress, but exclude perceived behavioural control. With regard to the trigger, only response efficacy impacted women’s behavioural intentions to use personal safety apps, while the magnitude of noxiousness and exposure expectancy did not. Women’s perception of the usefulness and ease of use of personal safety apps significantly impacted their behavioural intentions, ultimately impacting their perception of personal safety. Further, this study presented implications to theory and practice before concluding by stating research limitations and future directions.

Finite element analysis (FEA) is widely used to investigate the crushing performance of thin-walled tubes, and carry out parametric studies. However, simulation results are not always in good agreements with experimental results especially in terms of deformation modes in published literature. In this paper, a systematic FEA study will be conducted to evaluate two main simulation techniques using indentation triggers and buckling modes to introduce imperfections in FEA. Axial compressive tests were first carried out on three types of thin-walled circular tubes with different geometrical parameters. The finite element models were subsequently developed and used to explore the effects of indentation triggers and buckling modes on the deformation modes and force–displacement curves of thin-walled tubes. The influences of indentation depths and indentation positions on the crushing performance were investigated. Similarly, the effects of the order of buckling modes and scale factors on the crushing characteristics were examined as well. It has been found that for thin-walled circular tubes, a suitable simulation technique with indentation triggers or buckling modes can be employed to precisely mimic the deformation mode and corresponding force–displacement curve. This study is expected to provide some practical techniques and insights into the numerical simulation of circular tubes.

The CMS experiment has been designed with a 2-level trigger system: the Level 1 Trigger, implemented on custom-designed electronics, and the High Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. A software trigger system requires a tradeoff between the complexity of the algorithms running on the available computing power, the sustainable output rate, and the selection efficiency. Here we will present the performance of the main triggers used during the 2012 data taking, ranging from simpler single-object selections to more complex algorithms combining different objects, and applying analysis-level reconstruction and selection. We will discuss the optimisation of the triggers and the specific techniques to cope with the increasing LHC pile-up, reducing its impact on the physics performance.

Since Run-1 of the LHC, CMS has taken the opportunity to improve further particle reconstruction. A number of improvements were made to the hadronic tau reconstruction and identification algorithms. In particular, the reconstruction of the tau decay products leaving deposits in the electromagnetic calorimeter was improved to better model signal of ${\pi }^0$ from $\tau$ decays. This modification improves energy response and removes the tau footprint from isolation area. In addition to this, improvements were made to discriminators that combine isolation and tau lifetime variables, and the rejection of electrons misidentified as hadronic taus was improved using multivariate techniques. The results of these improvements using 13 TeV data at LHC Run-2 are presented and validation of tau identification using a variety of techniques has been highlighted.

Numerous surgical approaches have been described for treating patients suffering with stenosing tenosynovitis. The usual surgical descriptions differ mainly by the type of skin incision utilized. The goal of surgery is to completely release the A1 pulley, thereby allowing unimpeded motion of the flexor tendons. We describe a minimally invasive endoscopic technique to address this condition in the fingers.

Background: The purpose of this meta-analysis is to provide an evidence-based overview of the effectiveness of corticosteroid injection for the treatment of stenosing tenosynovitis (trigger digits). We have analysed only randomised control trials (RCTs) which compared the effectiveness of corticosteroid injections with control injections.

Methods: The Cochrane Library, PubMed, Medline, Web of Science and Scopus were searched to identify relevant studies. The keywords for search in the database were (‘stenosing tenosynovitis’ OR ‘trigger finger’) AND injections. After screening titles and abstracts of these studies, full-text articles of studies that fulfilled the selection criteria were obtained. For the meta-analysis, we determined the pooled mean failure rate, odds ratio (OR), relative risk (RR) and 95% confidence intervals (CI) for the risk of failure rate between the corticosteroid injection group and the control group through the random-effects model.

Results: Six RCTs were found that involved 368 participants. The corticosteroid injection group included 190 patients and 178 patients were included in the control group. The pooled estimate of successful treatment in the corticosteroid injections group was 63.68 ± 5.32% and that in the control group was 27.53 ± 11.52%. The pooled RR of treatment failure between the corticosteroid injection group and the control group was 0.49 (95% CI 0.40–0.60). The pooled OR of treatment failure between the corticosteroid injection group and the control group was 0.18 (95% CI 0.08–0.44). All the included studies reported either mild or no complications with corticosteroids or placebo injections.

Conclusions: In the treatment of stenosing tenosynovitis, the corticosteroid injections have better outcomes compared to the control injections and this meta-analysis provides significant evidence of the effectiveness of corticosteroid injection for stenosing tenosynovitis with minimal adverse effects.

Level of Evidence: Level II (Therapeutic)

The ATLAS detector trigger system needs to reduce the incoming rate of 40 MHz at design luminosity to around 200 Hz. The access to detector information must be fast so that trigger algorithms can run within a very short time budget (40ms at Level-2 and ≈ 4s at Event Filter). This work presents the modifications implemented to the calorimeter software data preparation which resulted in a gain of almost six times in data unpacking processing speed. Application to cosmic rays acquisition is also shown.

The ATLAS experiment at the Large Hadron Collider has a trigger system designed to keep high effiency for interesting events while achieving a rejection of low transverse momentum physics of about 10⁷, thus reaching the ~200 events/s storage capability of the Data Aquisition system. A three-levels structure has been implemented for this purpose, as described in this work for the case of the muon trigger system. After describing the implementation, some performance results are presented in terms of final trigger rates, resolutions, efficiencies, background rejection and algorithm latency.

Triggering on hadronic taus at the LHC is a difficult task due to the high rate and occupancy of the events. On the other hand, the tau trigger increases the discovery potential of ATLAS in many physics channels, among others the Standard Model or SuperSymmetric Higgs (charged or neutrals) production. In order to cope with the rate and optimize the efficiency on important physics channels, the results of the current simulation studies indicate that the ATLAS tau trigger should be used either with relatively high transverse momentum thresholds alone, or with more relaxed threshold requirements in combination with other triggers, like the missing transverse energy trigger or a leptonic or jet trigger.

In this contribution we describe the ATLAS tau trigger, and we present some of the current results from the simulation studies, focusing both on early physics and on physics at high luminosity.

The CDF II eXtremely Fast Tracker (XFT) is the trigger processor which reconstructs charged particle tracks in the transverse plane of the central tracking chamber. The XFT tracks are also extrapolated to the electromagnetic calorimeter and muon chambers to generate trigger electron and muon candidates. The XFT is crucial for the entire CDF II physics program: it detects high p_T leptons from W/Z and heavy flavor decays and, in conjunction with the Level 2 processors, it identifies secondary vertices from beauty decays. The XFT has thus been crucial for the recent measurement of the oscilation and Σ_b discovery. The increase of the Tevatron instantaneous luminosity demanded an upgrade of the system to cope with the higher occupancy of the chamber. In the upgraded XFT, three dimensional tracking reduces the level of fake tracks and measures the longitudinal track parameters, which strongly reinforce the trigger selections. This allows to mantain the trigger perfectly efficient at the record luminosities 2–3·10³²cm^-2s^-1 and to mantain intact the CDF II high luminosity physics program, which includes the Higgs search. The architecture, the used technology, the performance and the impact of the upgraded XFT on the entire CDF II trigger strategy are reviewed.

The three-level Trigger and DAQ system of ATLAS is designed to be very selective while preserving the full physics potential of the experiment; out of the ~1 GHz of p-p interactions provided by the LHC at nominal operating conditions, ~200 events/sec are retained. This paper focuses on the muon reconstruction and selection algorithms employed at the last trigger level. One implements an "outside-in" approach; it starts from a reconstruction in the Muon Spectrometer (MS) and performs a backward extrapolation to the interaction point and track combination in the Inner Detector (ID). The other implements an "inside-out" strategy; it starts muon reconstruction from the ID and extrapolates tracks to MS. Algorithm implementations and results on data from real cosmic rays and simulated collisions are described.

Tau lepton, being the heaviest of all known leptons (m_T = 1776.84 ± 0.17MeV), is of special importance. Due to its short lifetime, with (cT = 87.11µm), it decays inside the beam pipe. The identification of tau is, therefore, done through its decay products inside the detector. A tau jet can be identified through the presence of a well collimated calorimeter cluster with a small number of associated tracks.

The tau lepton decays into electron or muons 35% of the time, while 65% of its decays include hadrons, mostly pions. The events where tau decays into leptons can be triggered by low E_T threshold electron or muon trigger. A dedicated tau trigger has been designed and implemented at the ATLAS experiment to select events where a tau lepton decays into hadrons. Triggering on tau events will not only help in understanding the standard model (SM) processes during early running but will also increase the discovery potential of the ATLAS detector through searches for Higgs boson and supersymmetric particles at high luminosities.

The cosmics-ray data at ATLAS have provided a valuable handle to optimize and commission the ATLAS detector before beam collisions. In this process the ATLAS tau trigger algorithms have been exercised and the hardware-based first level rates studied.