516 research outputs found

    Silurian plutonism in the Trinity terrane (Neoproterozoic and Ordovician), Klamath Mountains, California, United States

    Get PDF
    New data indicate that the Trinity terrane of northern California is a polygenetic composite terrane rather than a single slice of oceanic lithosphere. We suggest approximately one third of the Trinity terrane consists of Silurian intrusive rocks that represent the roots of a previously unrecognized Silurian magmatic arc. Crosscutting relations and U‐Pb zircon isotopic data document at least one early Paleozoic deformation in the Trinity terrane of northern California. A ductile shear zone between Neoproterozoic metagabbro and Ordovician(?) harzburgite is intruded by the Upper Silurian China Mountain pluton. This evidence indicates a major early Paleozoic shear zone formed in the eastern Klamath Mountains after the Middle Ordovician but prior to Late Silurian plutonism

    Anticoagulant rodenticides in red kites (Milvus milvus) in Britain in 2017 and 2018

    Get PDF
    Second generation anticoagulant rodenticides (SGARs) can be toxic to all mammals and birds. Various studies have shown that, in Britain, there is widespread exposure to SGARs in a diverse range of predatory mammals and birds, including red kites (Milvus milvus) which scavenge dead rats, a target species for rodent control. The Wildlife Incident Monitoring Scheme (WIIS) and the Predatory Bird Monitoring Scheme (PBMS) have shown that some mortalities result from this secondary exposure. In the present study, we analysed liver SGAR residues in 77 red kites that had been found dead in Britain in either 2017 or 2018. The carcasses were submitted to and necropsied by the Disease Risk Analysis and Health Surveillance (DRAHS) programme, the PBMS, the WIIS for England & Wales, the WIIS for Scotland and the Raptor Health Scotland study; the livers from the kites were subsequently analysed for SGAR residues. All the organisations are partners in the WILDCOMS network that promotes collaboration among surveillance schemes that monitor disease and contaminants in vertebrate wildlife. All of the 66 kites from England & Wales and 10 of the 11 red kites from Scotland had detectable liver residues of at least one SGAR. When considering the sample of kites as a whole, brodifacoum, difenacoum and bromadiolone were each detected in 73, 71 and 60 kites, respectively. Difethialone was found in 11 individuals while flocoumafen was detected in only one bird. Sum liver SGAR concentrations ranged between non-detected and 1218 ng/g wet wt. (arithmetic mean: 246 ng/g, median 154 ng/g). Post-mortem examinations indicated that 13 (16.8%) of red kites examined had internal haemorrhaging that was not associated with detectable trauma and had detectable liver SGAR concentrations. These birds had sum SGAR liver concentrations that ranged from 135 ng/g wet weight to 1218 ng/g wet weight. SGARs were considered a contributory cause of death in these cases. The stewardship scheme for anticoagulant rodenticides came fully into force in mid-2016 as re-registration of products for use in the UK was completed. A key aim is to reduce exposure of non-target wildlife to anticoagulant rodenticides but stewardship also aims to maintain efficacious rat control and so the number and density of AR-contaminated rats may remain unchanged. However, diligent searching, removal and safe disposal of poisoned rats, as promoted by stewardship, might be expected to reduce the availability of poisoned dead rats to red kites [and other scavengers] and thereby reduce the proportion of birds that are exposed and/or the magnitude of exposure. Concomitant with stewardship was a relaxation of the indoor use only restriction previously applied to brodifacoum, flocoumafen and difethialone, the three most acutely toxic SGARs. Any consequent increase in outdoor use of these three SGARs could increase the risk of secondary exposure in red kites. We therefore compared the data in the current report with that collected in 2015 and 2016 to determine if there was any evidence of a change in pattern or magnitude of exposure in red kites that might be connected to stewardship and/or change in usage restriction. The proportion of red kites exposed to SGARs in 2015 (90.6%), 2016 (89.6%) 2017 (96,4%) and 2018 (100%) was always 90% or more; the higher percentages in 2017 and 2018 were principally due to a greater proportion of birds from Scotland containing residues. Brodifacoum and difenacoum were the most prevalent compounds (89% of red kites across the four years for each compound) along with bromadiolone (75%). On average, there were residues of three different SGARs in each kite liver. There was no significant difference between years in liver sum (Σ) SGAR concentrations. We investigated if there was a change between years in the exposure of red kites to brodifacoum, flocoumafen and difethialone, the compounds for which indoor only usage restrictions were relaxed in 2016. To enable statistical analysis of data on residue prevalence, it was necessary to pool the data into two-year blocks. Data on presence/absence of detectable brodifacoum, flocoumafen or difethialone residues were therefore compared for 2015/16 (pre and year of implementation of change in usage restriction) and 2017/18 (post-change in usage restriction). The proportion of red kites with detectable residues was 82% (50 out of 61 red kites) in 2015/16 but significantly higher (95%; 73 out of 77 red kites) in 2017/18. However, there was also an increase [albeit not statistically significant] in the proportion of red kites with detectable liver difenacoum or bromadiolone residues (90% in 2015/16 vs. 97% in 2017/18). Therefore, these data may simply reflect an increase in the prevalence of exposure to SGARs generally rather than any effect of change in usage restriction. There was no difference between the four years in the summed magnitude of liver brodifacoum, difethialone and flocoumafen concentrations. The percentage of red kites examined that were diagnosed as birds in which SGARs were implicated as a contributory cause of death did not differ significantly between individual years nor show a significant trend across the years; the overall average across the four years was 22%. However, if data were pooled by pairs of years (2017/8 vs 2015/16), the proportion of red kites for which SGARs were implicated as a contributory cause of death was lower (18%) in 2017/18 than in 2015/16 (33%) for red kites from England & Wales. Our findings do not indicate that there has been any reduction in exposure in red kites to SGARs following implementation of stewardship, in terms of either the proportion of individuals exposed or the magnitude of residues detected. There is some evidence (depending upon the statistical approach used) that the proportion of red kites in which SGARs were implicated as a contributory mortality factor has decreased in more recent years. There was no clear evidence that relaxation of usage restrictions on brodifacoum, difethialone and flocoumafen has altered the pattern of residue accumulation in red kites to date

    Second generation anticoagulant rodenticide residues in red kites 2020

    Get PDF
    Second generation anticoagulant rodenticides (SGARs) can be toxic to all mammals and birds if consumed. Various studies have shown that, in Britain, there is widespread exposure to SGARs in a diverse range of predatory mammals and birds, including red kites (Milvus milvus) which scavenge dead rats, a target species for rodent control. The Wildlife Incident Investigation Scheme1 (WIIS) and the Predatory Bird Monitoring Scheme (PBMS) have shown that some mortalities result from this secondary exposure. In the present study, we analysed liver SGAR residues in 25 red kites that had been found dead in Britain in 2020. The carcasses were submitted to and necropsied by the Disease Risk Analysis and Health Surveillance (DRAHS) programme, the PBMS, the WIIS for England & Wales, the WIIS for Scotland and the Raptor Health Scotland study. All the organisations are partners in the WILDCOMS (Wildlife Disease & Contaminant Monitoring & Surveillance Network) network that promotes collaboration among surveillance schemes that monitor disease and contaminants in vertebrate wildlife in the UK. The UK Rodenticide Stewardship Regime began to come into force in mid-2016 as reregistration of products for use in the UK was approved by the HSE; full implementation of the scheme was in early 2018. The key aim of this stewardship initiative is to support competence among all SGAR users, a potential benefit of this may be the reduced exposure of non-target wildlife to anticoagulant rodenticides. However, the number and density of SGAR-contaminated rats may remain unchanged although diligent searching, removal and safe disposal of poisoned rats, as promoted by the stewardship regime, might be expected to reduce the availability of poisoned dead rats to red kites (and other scavengers) and thereby reduce the proportion of birds that are exposed and/or the magnitude of exposure. Concomitant with the stewardship scheme was a relaxation of the indoor-use-only-restriction previously applied to brodifacoum, flocoumafen and difethialone, the three most acutely toxic SGARs. Any consequent increase in outdoor use of these three SGARs could increase the risk of secondary exposure in red kites. We therefore compared the data in the current report with that collected in 2015 and 2016 to determine if there was any evidence of a change in pattern or magnitude of exposure in red kites that might be connected to stewardship and/or change in usage restriction. All but one of the 21 red kites from England & Wales and two of the four red kites from Scotland had detectable liver residues of at least one type of SGAR. When considering the sample of red kites as a whole, brodifacoum, difenacoum and bromadiolone were each detected in 21, 19 and 17 red kites, respectively. Difethialone was found in four individuals while flocoumafen was detected in one bird. The proportion of analysed red kites exposed to SGARs in 2015 (91%), 2016 (90%) 2017 (96%), 2018 (100%) 2019 (91%) and 2020 (88%) was similar at circa 88% or more; the higher percentages in 2017 and 2018 were principally due to a greater proportion of birds from Scotland containing residues than observe in other years. Difenacoum, brodifacoum, and bromodialone were the most prevalent compounds (detected in 86%, 85%, and 76% of red kites across the six years for each compound, respectively). On average, there were detectable residues of three different SGARs in each red kite liver likely demonstrating multiple exposures. Sum liver SGAR concentrations in birds from 2020 ranged between non-detectable and 1086 ng/g wet weight (arithmetic mean: 371 ng/g wet weight, median 307 ng/g wet weight). Necropsy examinations indicated that three (13%) of red kites examined had internal haemorrhaging that was not associated with detectable trauma and also had detectable liver SGAR concentrations. These birds had sum SGAR liver concentrations of 663, 905 and 1086 ng/g wet weight. SGARs were considered a contributory cause of death resulting from unspecified use in these cases. SGARs were a contributory cause of death in 17% of the red kite cases examined across all six years. Over the period 2015 to 2020, a reduction has been observed in the percentage of red kites examined that were diagnosed as birds in which SGARs were implicated as a contributory cause of death. However, given that the WIIS scheme specifically examines suspected poisoning incidents, it is likely that poisoned birds are over represented in this sample compared to the population as a whole in all six years. Due to these reasons, caution should be used when interpreting evident changes in mortality rates due to the sampling protocols used in this study that may lead to over reporting of mortality rates, and those rates being subject to variations in relative contribution of the WIIS and PBMS to each year’s sample. There was no statistically significant difference between years, irrespective of cause of death, in median summed SGAR residues, and no evidence that the magnitude of accumulated summed SGAR residues has changed consistently over time. Sum bromadiolone and difenacoum concentrations were lower in 2016 than 2015, however, there was no difference for sum brodifacoum, flocoumafen, and difethialone concentrations. Data on presence/absence of detectable brodifacoum, flocoumafen or difethialone residues were compared for 2015/16 and 2017/18/19/20. The proportion of red kites with detectable residues of these three SGARs was 82% in 2015/16 and similar proportions were observed in 2017/18/19/20 (86%). Similarly, there was no significant difference in the proportion of red kites with detectable liver difenacoum or bromadiolone residues (90% in 2015/16 vs. 93% in 2017/18/19/20). Since the implementation of the stewardship regime no difference in exposure pattern relating to active ingredient has been detected. Our findings do not indicate that there has been a broad scale change in exposure in red kites to SGARs following implementation of stewardship in terms of either the proportion of the sample exposed or the magnitude of sum SGARs residues detected. There is some evidence (depending upon the statistical approach used) that the proportion of red kites in which SGARs were implicated as a contributory mortality factor has decreased in more recent years. Alternative approaches to monitoring SGARs in red kites could be considered that analyses a random but representative sample, and as part of such a programme there may also be value in monitoring SGARs in the blood of tracked individuals. There was no clear evidence that relaxation of usage restrictions on brodifacoum, difethialone and flocoumafen has altered the pattern of residues for these compounds in red kites to date. However, data following full implementation of the rodenticide stewardship scheme is currently limited to four years

    A two-component pre-seeded dermal-epidermal scaffold

    Get PDF
    We have developed a bilayered dermal-epidermal scaffold for application in the treatment of full-thickness skin defects. The dermal component gels in situ and adapts to the lesion shape, delivering human dermal fibroblasts in a matrix of fibrin and cross-linked hyaluronic acid modified with a cell adhesion-promoting peptide. Fibroblasts were able to form a tridimensional matrix due to material features such as tailored mechanical properties, presence of protease-degradable elements and cell-binding ligands. The epidermal component is a robust membrane containing cross-linked hyaluronic acid and poly-l-lysine, on which keratinocytes were able to attach and to form a monolayer. Amine-aldehyde bonding at the interface between the two components allows the formation of a tightly bound composite scaffold. Both parts of the scaffold were designed to provide cell-type-specific cues to allow for cell proliferation and form a construct that mimics the skin environment.D.S.K. acknowledges funding from the Biotechnology Research Endowment from the Department of Anesthesiology at Boston Children's Hospital. I.P.M. acknowledges the Portuguese Foundation for Science and Technology for the grant BD/39396/2007 and the MIT-Portugal Program. D.G. acknowledges the Swiss National Science Foundation for a post-doctoral fellowship (PBGEP3-129111). B.P.T. acknowledges an NIR Ruth L. Kirschstein National Research Service Award (F32GM096546)

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

    Get PDF
    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

    Get PDF
    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

    Get PDF
    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

    Get PDF
    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

    Get PDF
    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

    Get PDF
    A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters
    corecore