2,506 research outputs found

    The CMS Trigger System

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    A Global Labour History Perspective

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    UIDB/04209/2020 UIDP/04209/2020The Carnation Revolution in 1974 in Portugal marked the end of the last European colonial empire. This was an anachronistic empire of a small peripheral country that since 1961 had been waging a relentless war in Africa to stifle the national liberation movements that contested for control of colonial territory and organized growing sectors of the population, namely the forced labourers who guaranteed a significant accumulation of capital for the beneficiaries of the colonial regime. In this chapter we seek to describe the moment and the conditions in which Portugal freed itself from a long dictatorship of 48 years and the decisive influence of the struggles in the colonies on the military revolt that started the revolution in the metropolis and ended the war to stem the movement towards independence in the former colonial territories. Workers in Portugal and its colonies in Africa alike embarked on a process that created the conditions for the Carnation Revolution and the formation of new independent African states in 1974 and 1975. Together, they succeeded in defeating the longest-running colonial dictatorship of the twentieth century.publishersversionpublishe

    Test beam operation of the CMS calorimeter trigger synchronization boards

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    The CMS experiment uses information from its electromagnetic and hadronic calorimeters and muon detectors to decide whether to readout the whole detector. For such a task to be successful, all trigger primitives pushed through the trigger decision tree must be flawlessly aligned in time for operation at 40 MHz. Both calorimeters in CMS use the Synchronization Link Board for this purpose. In this article we report on the results of tests of this board using realistic beam conditions, which demonstrate the soundness of the adopted architecture and synchronization principle

    Anti-Hepatocellular Carcinoma (HepG2) activities of Monoterpene Hydroxy Lactones isolated from the Marine Microalga Tisochrysis Lutea

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    Tisochrysis lutea is a marine haptophyte rich in omega-3 polyunsaturated fatty acids (e.g., docosahexaenoic acid (DHA)) and carotenoids (e.g., fucoxanthin). Because of the nutraceutical applications of these compounds, this microalga is being used in aquaculture to feed oyster and shrimp larvae. In our earlier report, T. lutea organic crude extracts exhibited in vitro cytotoxic activity against human hepatocarcinoma (HepG2) cells. However, so far, the compound(s) accountable for the observed bioactivity have not been identified. Therefore, the aim of this study was to isolate and identify the chemical component(s) responsible for the bioactivity observed. Bioassay-guided fractionation through a combination of silica-gel column chromatography, followed by preparative thin layer chromatography (PTLC), led to the isolation of two diastereomers of a monoterpenoid lactone, namely, loliolide (1) and epi-loliolide (2), isolated for the first time in this species. The structural elucidation of both compounds was carried out by GC-MS and 1D (1H and 13C APT) and 2D (COSY, HMBC, HSQC-ed, and NOESY) NMR analysis. Both compounds significantly reduced the viability of HepG2 cells and were considerably less toxic towards a non-tumoral murine stromal (S17) cell line, although epi-loliolide was found to be more active than loliolide.FCT, Portugal: UID/Multi/04326/2019, UID/MAR/04292/2020 (MARE), UID/Multi/04046/2020 (BioISI) and from the grant of 0055 ALGARED +5E—INTERREG V-A; SFRH/BD/116604/2016; SFRH/BD/105541/2014info:eu-repo/semantics/publishedVersio

    Search for a non-standard-model Higgs boson decaying to a pair of new light bosons in four-muon final states

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    Results are reported from a search for non-standard-model Higgs boson decays to pairs of new light bosons, each of which decays into the μ+μ− final state. The new bosons may be produced either promptly or via a decay chain. The data set corresponds to an integrated luminosity of 5.3 fb−1 of proton–proton collisions at View the MathML source, recorded by the CMS experiment at the LHC in 2011. Such Higgs boson decays are predicted in several scenarios of new physics, including supersymmetric models with extended Higgs sectors or hidden valleys. Thus, the results of the search are relevant for establishing whether the new particle observed in Higgs boson searches at the LHC has the properties expected for a standard model Higgs boson. No excess of events is observed with respect to the yields expected from standard model processes. A model-independent upper limit of 0.86±0.06 fb on the product of the cross section times branching fraction times acceptance is obtained. The results, which are applicable to a broad spectrum of new physics scenarios, are compared with the predictions of two benchmark models as functions of a Higgs boson mass larger than 86 GeV/c2 and of a new light boson mass within the range 0.25–3.55 GeV/c2Peer Reviewe

    Search for heavy resonances in the W/Z-tagged dijet mass spectrum in pp collisions at 7 TeV

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    A search has been made for massive resonances decaying into a quark and a vector boson, qW or qZ, or a pair of vector bosons, WW, WZ, or ZZ, where each vector boson decays to hadronic final states. This search is based on a data sample corresponding to an integrated luminosity of 5.0 fb^-^1 of proton-proton collisions collected in the CMS experiment at the LHC in 2011 at a center-of-mass energy of 7 TeV. For sufficiently heavy resonances the decay products of each vector boson are merged into a single jet, and the event effectively has a dijet topology. The background from QCD dijet events is reduced using recently developed techniques that resolve jet substructure. A 95% CL lower limit is set on the mass of excited quark resonances decaying into qW (qZ) at 2.38 TeV (2.15 TeV) and upper limits are set on the cross section for resonances decaying to qW, qZ, WW, WZ, or ZZ final states.Peer Reviewe

    Framework for a risk assessment model to apply in virtual/collaborative enterprises

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    Risk assessment is a theme of large spectrum applied in different fields. In the context of Virtual / Collaborative Enterprises there are several risks whose assessment should be aware to avoid undesirable consequences either for entire networked or for a partner in particular. The objective of this work is centered on the creation of a framework / guidelines to serve as a basis for the creation of a better risk assessment model for Virtual / Collaborative Enterprises. This work analyzed the few models available in the literature and identified some gaps that were used to purpose complementary guidelines for the design and / or improve the future risk assessment models. The pointed guidelines covered three important topics: risk factors; assessment methods; and the impact in different life cycle phases of a Virtual / Collaborative Enterprise. Considering the results of the work it is our conviction that there is space to improve the research in this field and a more robust and flexible risk assessment model should be developed. (C) 2021 The Authors. Published by Elsevier B.V.- (undefined

    Measurement of the Production Cross Section for Pairs of Isolated Photons in pppp collisions at s=7\sqrt{s}=7 TeV

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    The integrated and differential cross sections for the production of pairs of isolated photons is measured in proton-proton collisions at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 36 inverse picobarns is analysed. A next-to-leading-order perturbative QCD calculation is compared to the measurements. A discrepancy is observed for regions of the phase space where the two photons have an azimuthal angle difference, Δ(ϕ)\Delta(\phi), less than approximately 2.8.Peer Reviewe

    Inclusive search for supersymmetry using the razor variables in pppp collisions at s=7\sqrt{s}=7 TeV

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    An inclusive search is presented for new heavy particle pairs produced in s\sqrt{s} = 7 TeV proton-proton collisions at the LHC using 4.7 +/- 0.1 inverse femtobarns of integrated luminosity. The selected events are analyzed in the 2D razor space of MR, an event-by-event indicator of the heavy particle mass scale, and R, a dimensionless variable related to the missing transverse energy. The third-generation sector is probed using the event heavy-flavor content. The search is sensitive to generic supersymmetry models with minimal assumptions about the superpartner decay chains. No excess is observed in the number of events beyond that predicted by the standard model. Exclusion limits are derived in the CMSSM framework as well as for simplified models. Within the CMSSM parameter space considered, gluino masses up to 800 GeV and squark masses up to 1.35 TeV are excluded at 95% confidence level depending on the model parameters. The direct production of pairs of stop or sbottom quarks is excluded for masses as high as 400 GeV.Peer Reviewe

    Search for signatures of extra dimensions in the diphoton mass spectrum at the Large Hadron Collider

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    A search for signatures of extra dimensions in the diphoton invariant-mass spectrum has been performed with the CMS detector at the LHC. No excess of events above the standard model expectation is observed using a data sample collected in proton-proton collisions at sqrt(s) = 7 TeV corresponding to an integrated luminosity of 2.2 inverse femtobarns. In the context of the large-extra-dimensions model, lower limits are set on the effective Planck scale in the range of 2.3-3.8 TeV at the 95% confidence level. These limits are the most restrictive bounds on virtual-graviton exchange to date. The most restrictive lower limits to date are also set on the mass of the first graviton excitation in the Randall-Sundrum model in the range of 0.86-1.84 TeV, for values of the associated coupling parameter between 0.01 and 0.10.Peer Reviewe
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