142 research outputs found

    Gammaherpesvirus-Induced Lung Pathology Is Altered in the Absence of Macrophages

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    The purpose of this study was to examine the lung pathogenesis of murine gammaherpesvirus (MHV-68) infection in mice that lack CC chemokine receptor CCR2, an important receptor for macrophage recruitment to sites of inflammation. BALB/c and CCR2 −/− mice were inoculated intranasally (i.n.) with MHV-68 and samples were collected during acute infection (6 dpi) and following viral clearance (12 dpi). Immunohistochemistry was used to determine which cells types responded to MHV-68 infection in the lungs. Lung pathology in infected BALB/c mice was characterized by a mixed inflammatory cell infiltrate, necrosis, and increased alveolar macrophages by 12 dpi. Immunohistochemistry showed intense positive staining for macrophages. CCR2 −/− mice showed greater inflammation in the lungs at 12 dpi than did BALB/c mice, with more necrosis and diffuse neutrophil infiltrates in the alveoli. Immunohistochemistry demonstrated much less macrophage infiltration in the CCR2 −/− mice than in the BALB/c mice. These studies show that CCR2 is involved in macrophage recruitment in response to MHV-68 infection and illustrates how impairments in macrophage function affect the normal inflammatory response to this viral infection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41345/1/408_2004_Article_2535.pd

    Measurement and interpretation of same-sign W boson pair production in association with two jets in pp collisions at s = 13 TeV with the ATLAS detector

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    This paper presents the measurement of fducial and diferential cross sections for both the inclusive and electroweak production of a same-sign W-boson pair in association with two jets (W±W±jj) using 139 fb−1 of proton-proton collision data recorded at a centre-of-mass energy of √s = 13 TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed by selecting two same-charge leptons, electron or muon, and at least two jets with large invariant mass and a large rapidity diference. The measured fducial cross sections for electroweak and inclusive W±W±jj production are 2.92 ± 0.22 (stat.) ± 0.19 (syst.)fb and 3.38±0.22 (stat.)±0.19 (syst.)fb, respectively, in agreement with Standard Model predictions. The measurements are used to constrain anomalous quartic gauge couplings by extracting 95% confdence level intervals on dimension-8 operators. A search for doubly charged Higgs bosons H±± that are produced in vector-boson fusion processes and decay into a same-sign W boson pair is performed. The largest deviation from the Standard Model occurs for an H±± mass near 450 GeV, with a global signifcance of 2.5 standard deviations

    Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector

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    A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, , and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion

    Search for dark photons in rare Z boson decays with the ATLAS detector

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    A search for events with a dark photon produced in association with a dark Higgs boson via rare decays of the standard model Z boson is presented, using 139     fb − 1 of √ s = 13     TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. The dark boson decays into a pair of dark photons, and at least two of the three dark photons must each decay into a pair of electrons or muons, resulting in at least two same-flavor opposite-charge lepton pairs in the final state. The data are found to be consistent with the background prediction, and upper limits are set on the dark photon’s coupling to the dark Higgs boson times the kinetic mixing between the standard model photon and the dark photon, α D ϵ 2 , in the dark photon mass range of [5, 40] GeV except for the Υ mass window [8.8, 11.1] GeV. This search explores new parameter space not previously excluded by other experiments

    Combined measurement of the Higgs boson mass from the H → γγ and H → ZZ∗ → 4ℓ decay channels with the ATLAS detector using √s = 7, 8, and 13 TeV pp collision data

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    A measurement of the mass of the Higgs boson combining the H → Z Z ∗ → 4 ℓ and H → γ γ decay channels is presented. The result is based on 140     fb − 1 of proton-proton collision data collected by the ATLAS detector during LHC run 2 at a center-of-mass energy of 13 TeV combined with the run 1 ATLAS mass measurement, performed at center-of-mass energies of 7 and 8 TeV, yielding a Higgs boson mass of 125.11 ± 0.09 ( stat ) ± 0.06 ( syst ) = 125.11 ± 0.11     GeV . This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics

    Does biodiversity of estuarine phytoplankton depend on hydrology?

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    Phytoplankton growth in estuaries is controlled by factors such as flushing, salinity tolerance, light, nutrients and grazing. Here, we show that biodiversity of estuarine phytoplankton is related to flushing, and illustrate this for some European estuaries. The implications for the definition of reference conditions for quality elements in estuaries of different types are examined, leading to the conclusion that constraints on the number of estuarine and coastal types that may be defined for management purposes require that quality classes take into account natural variability within types, in order to be ecologically meaningful. We develop a screening model to predict the growth rate required for a phytoplankton species to be present under different flushing conditions and apply it to estuaries in the EU and US to show how changes in physical forcing may alter biodiversity. Additional results are presented on the consequences for eutrophication, showing that changes in residence time may interact with species-specific nutrient uptake rates to cause shifts in species composition, potentially leading to effects such as harmful algal blooms. We discuss applications for integrated coastal zone management, and propose an, approach to normalization of estuarine phytoplankton composition as regards species numbers.. (c) 2005 Elsevier B.V. All rights reserved

    A methodology for defining homogeneous water bodies in estuaries - Application to the transitional systems of the EU Water Framework Directive

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    A methodology is developed and tested for division of estuarine and coastal systems into water bodies for monitoring and management purposes. This division is often implicit in the choice of sampling stations and in pollution abatement measures applied to different locations - it is now an explicit requirement of European Union Directive 2000/60/EC (Water Framework Directive) and recommended by United States Agencies such as EPA and NOAA. The approach considers both natural characteristics and the human dimension, by means of a stepwise methodology, which considers, on the one hand, morphology and salinity distribution, and, on the other, appropriate indicators of pressure and state. In the present application, nitrogen and phosphorus loading was used as the pressure component and chlorophyll a and dissolved oxygen as indicators of state. The criteria for system division were defined based on (1) an adimensional shape factor and salinity classes for the natural component; and (2) a normalised pressure index and (ASSETS) eutrophication symptom classes for the human dimension. Water quality databases and GIS were used to develop spatial distributions for the various components, and the results were aggregated into a final water body division, using tidal excursion as a "common sense" test. The methodology was applied to three well-studied systems in Portugal, a tubular estuary (Mondego), a wide lagunal estuary (Sado) and a coastal barrier island system (Ria Formosa). Although a final definition of water bodies will usually be a policy decision, this type of approach for the division of coastal systems into management units scientifically informs the decision-making process. (c) 2005 Elsevier Ltd. All rights reserved
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