Aspects of nucleolar metabolism in herpesvirus infected cells

The inhibition of ribosomal RNA production has been studied in Hela cells infected with pseudorabies virus (PrV). This showed that both synthesis and processing of ribosomal RNA was affected. Processing in PrV-infected Hela cells was at a reduced rate but did follow a similar pattern to that of mock-infected cells. The effect on synthesis of ribosomal RNA was more pronounced and was followed by a concomitant decrease in the total nucleolar area of the infected Hela cells. Polyacrylamide gel electrophoresis of fractions from mock-infected and PrV-infected Hela cells showed that a number of virus induced polypeptides were associated with the nucleus, nucleolus and the nucleolar chromatin. Some of these polypeptides were immediate early viral gene products. A number of viral induced polypeptides were shown to be associated with the nuclei and nucleoli of mock-infected Hela cells after incubation in vitro of isolated nuclei and cell extracts of both mock-infected and infected Hela cells. The RNA polymerase activity of isolated nuclei of PrV- infected Hela cells was lower than that of mock-infected. This was true both for total and for a-amanitin resistant activities. The difference in RNA polymerase activity between mock-infected and infected Hela cells remained unchanged after incubation of the nuclei in the presence of the detergent sarkosyl. Again incubation in the presence of extracts of mock-infected or infected cells did not alter relative activities in the normal assay whereas RMA polymerase activity in mock-infected Hela cell nuclei was reduced after a combined exposure to infected cell extracts followed by treatment with aarkosyl. This suggests that its inhibition of ribosomal RNA synthesis in Hela cells after infection with pseudorabies virus is by interference at the initiation level of the transcription process rather than the elongation level. It may be mediated by a viral-induced protein(s) associated with the nucleolar and nucleolar chromatin cell fractions

FPGA-Based Tracklet Approach to Level-1 Track Finding at CMS for the HL-LHC

During the High Luminosity LHC, the CMS detector will need charged particle tracking at the hardware trigger level to maintain a manageable trigger rate and achieve its physics goals. The tracklet approach is a track-finding algorithm based on a road-search algorithm that has been implemented on commercially available FPGA technology. The tracklet algorithm has achieved high performance in track-finding and completes tracking within 3.4 $\mu$s on a Xilinx Virtex-7 FPGA. An overview of the algorithm and its implementation on an FPGA is given, results are shown from a demonstrator test stand and system performance studies are presented.Comment: Submitted to proceedings of Connecting The Dots/Intelligent Trackers 2017, Orsay, Franc

Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

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Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe