1,168 research outputs found

    The stratigraphy, correlation, provenance and palaeogeography of the Skiddaw Group (Ordovician) in the English Lake District

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    A new lithostratigraphy is presented for the Skiddaw Group (lower Ordovician) of the English Lake District. Two stratigraphical belts are described. Five formations are defined in the Northern Fells Belt, ranging in age from Tremadoc to early Llanvirn. They are all mudstone or sandstone dominated, of turbidite origin; in ascending order they are named the Bitter Beck, Watch Hill, Hope Beck, Loweswater and Kirk Stile formations. Two formations are defined in the Central Fells Belt, ranging in age from late Arenig to Llanvirn. These are the Buttermere Formation - a major olistostrome deposit - overlain by the Tarn Moor Formation, consisting of turbidite mudstones with volcaniclastic turbidite sandstone beds. A revised graptolite and new acritarch biostratigraphy for the Skiddaw Group is presented with eight graptolite biozones and thirteen acritarch assemblages and sub-assemblages. The provenance of the group is assessed from detailed petrographical and geochemical work. This suggests derivation, in the early Ordovician, largely from an old inactive continental arc terrane lying to the south-east, with the appearance of juvenile volcanic material in the Llanvirn. Comparisons and correlations of the Skiddaw Group are made with the Isle of Man and eastern Ireland

    Chronic pain and opioid analgesic use : a case report

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    Opioids are often ineffective for managing chronic non-malignant pain. If prescribed, this should be as part of an opioid trial with clear aims of therapy, tapering/stopping if it is ineffective, or if it is causing adverse effects. Clinical guidance is available but there are many gaps in the evidence

    Mineral exploration in the Cockermouth area, Cumbria. Part 2: follow-up surveys

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    This report describes the results of geochemical, geological and geophysical surveys across three small areas of Carboniferous and Lower Palaeozoic rocks along the northern margin of the English Lake District. The areas were chosen from the appraisal of regional-scale survey data described by Cooper et al. (1991). In two of the areas, Ruthwaite and Tallentire, the objective was to provide more information on the extent and magnitude of fracture-controlled epigenetic baryte and base metal mineralisation. In the third area, at Whitrigg, brief surveys were carried out to aid the interpretation of unexplained geochemical and geophysical anomalies found during two projects carried out under the Mineral Exploration and Investment Grants Act (MEIGA). At Ruthwaite, where a mine formerly worked baryte from a fault separating Lower Palaeozoic and Carboniferous rocks, surface indications of further baryte mineralisation were found. Soil analyses indicated that mineralisation may be present along the continuation of the faultline worked at Ruthwaite and in the Eycott Volcanic Group rocks to the south of it. In this area relatively small, but in some circumstances perhaps economically attractive, deposits of baryte may be present under drift cover. In the Tallentire Hill area, geological mapping followed by traverse-based soil sampling showed that fracture-controlled mineralisation is widespread in the Carboniferous (Dinantian and Namurian) rocks. The fracture fillings consist dominantly of baryte, often accompanied by carbonate, with traces of copper and mercury. Where seen at surface the fracture fillings are too small, patchy and low-grade to be of any economic importance. Baryte mineralisation also occurs locally as patchy impregnations in sandstones. These are considered to be epigenetic deposits related to the fracture-controlled mineralisation. Trial geophysical surveys suggested that electrical methods may be useful in determining the extent of the mineralised sandstone. There is a possibility that more extensive baryte deposits may be present in the limestone succession underlying the mineralised sandstones. In the Whitrigg area, Carboniferous rocks are separated from Lower Palaeozoic rocks of the Eycott Volcanic Group by the easterly-trending Boundary Fault and north-westerly-trending Bothel Fault. Evidence from an old mineral working and the results of a soil survey indicate that patchy, epigenetic, fracture-controlled baryte and base metal mineralisation occurs along the Bothel Fault and, locally, in the adjacent rocks. A feature of this mineralisation is the presence of mercury, which is most abundant in a sample of brecciated and altered rock from the Eycott Volcanic Group. Prominent base metal in soil anomalies discovered by MEIGA-funded projects near Stangerhill are not associated with barium anomalies. It was concluded that these soil anomalies are most likely to be caused by secondary concentration in overburden, and that the source of metals may be a sub-cropping metalliferous horizon within the Carboniferous succession or, more probably, fracture-controlled mineralisation. Trial geophysical surveys carried out in all three areas indicated that in ground free of artificial sources the VLF(EM) and conductivity mapping methods could be useful for tracing faults beneath drift and providing information on drift thickness. Closely-spaced soil sampling proved effective for detecting mineralisation in areas where the drift cover is thin, and a trial soil-gas survey showed that this technique could also be useful for tracing faults beneath drift

    Compact boson stars in K field theories

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    We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.Comment: Latex, 45 pages, 25 figures, some references and comments adde

    Thermodynamics of Dipolar Chain Systems

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    The thermodynamics of a quantum system of layers containing perpendicularly oriented dipolar molecules is studied within an oscillator approximation for both bosonic and fermionic species. The system is assumed to be built from chains with one molecule in each layer. We consider the effects of the intralayer repulsion and quantum statistical requirements in systems with more than one chain. Specifically, we consider the case of two chains and solve the problem analytically within the harmonic Hamiltonian approach which is accurate for large dipole moments. The case of three chains is calculated numerically. Our findings indicate that thermodynamic observables, such as the heat capacity, can be used to probe the signatures of the intralayer interaction between chains. This should be relevant for near future experiments on polar molecules with strong dipole moments.Comment: 15 pages, 5 figures, final versio

    Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

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    We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to 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

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    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

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    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
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