Devonian hyoliths in South Africa, and their palaeoenvironmental significance

Hyoliths, an extinct group of molluscan or mollusc-like invertebrates that secreted elongate conical shells, are relatively uncommon and often overlooked members of Middle Palaeozoic marine fossil assemblages. They have been recorded from a number of widespread localities in the argillaceous Gydo and Voorstehoek Formations of the Bokkeveld Group. Most of the specimens are crushed or are without opercula and other taxonomically important features of the aperture and therefore must remain indeterminate. The hyoliths occur in bioturbated mudstones along with brachiopods, trilobites, bivalves, gastropods, crinoids, cephalopods and conulariids. This assemblage is interpreted as representing an inner shelf community that occupied quiet waters below wave base seaward of the prograding Bokkeveld deltas. Unlike many of the other elements of the shelf community, the epifaunal, deposit-feeding hyoliths are not found in the shallower water communities and can be taken as diagnostic of the offshore environments

Morphologic and Ontogenetic Patterns in Elasmosaur Neck Length, with Comments on the Taxonomic Utility of Neck Length Variables

Elasmosaur cervical vertebrae are common fossils, but their taxonomic utility is limited due to a lack of understanding concerning their shape within and among taxa. In this paper, we analyze data from complete elasmosaur necks in an attempt to quantify and understand the variation in centrum dimensions. In accord with previous studies, variation in cervical centrum shape is found to stem from at least three sources: ontogeny, intracolumn variation, and intercolumn or taxonomic variation. Ontogenetic variability seems reminiscent of that seen in Cryptoclidus, with an overall positive allometry in the length of all centra that is accentuated in the mid-cervical region. In adult elasmosaurs, the longest centra occur in the middle of the neck, and centra in this region are longer than those at either end. This pattern yields a distinctively bowed shape curve when a shape metric such as VLI or PC2 score is graphed against vertebral position. Centrum length shows minor variation from centrum to centrum in all elasmosaurs, but a small group of extreme, \u27elongate\u27 animals have a much higher degree of variability. Animals in this group show significant changes in centrum dimensions late in ontogeny. The taxonomic utility of centrum measures is limited because there is no single pattern of centrum shape common to all taxa; variability is the rule, and therefore caution is necessary when using dimensions to diagnose taxa. There do seem to be two morphotypes of elasmosaurs, however. The first is a relatively conservative group with centrum dimensions similar to those of Brancasaurus, and that achieves a long neck by adding vertebrae. A second, elongate group has centra that are very long, and there is great variability from one centrum to another in the same column. Surprisingly, the number of cervical centra is not a highly variable trait in most elasmosaurs. The elongate taxa appear to be restricted to the Western Interior Seaway in the Late Cretaceous, although there is some indication that Tuarangisaurus might be elongate as well. In general, elasmosaur vertebrae have some taxonomic utility, but only at the extremes of their shape range, if the specimens are adults, and only if their position in the column is known with some certainty

An unusual new fossil shark (Pisces: Chondrichthyes) from the Late Devonian of South Africa

A new stem-group chondrichthyan fish, PlesioselacJllIs macracanthlls gen. et sp. nov., is described from the Late Devonian Witpoort Formation, representing an estuarine lagoon site, near Grahamstown, South Africa. Based on a single, fairly complete specimen, it is distinctive in its a single dorsal fin braced by a large, stout spine with numerous ribs and posterior denticles, apparently no second dorsal or anal fin, an amphistylic jaw suspension, and a distinctive triangular palatoquadrate. It is suggested that the species may represent a high-latitude, Late Devonian relict taxon

The first Bothriolepsis-associated Devonian fish fauna from Africa

An advanced diplacanthid (Climatiiformes) is described from a Famennian estuarine environment of South Africa. It is characterized by having exceptionally long thin fin spines and a deep body form. Unusual details of the fins and fin spine insertions are preserved. This is the first record of a diplacanthid from the Southern Hemisphere

An unusual new fossil shark (Pisces: Chondrichthyes) from the Late Devonian of South Africa

A new stem-group chondrichthyan fish, PlesioselacJllIs macracanthlls gen. et sp. nov., is described from the Late Devonian Witpoort Formation, representing an estuarine lagoon site, near Grahamstown, South Africa. Based on a single, fairly complete specimen, it is distinctive in its a single dorsal fin braced by a large, stout spine with numerous ribs and posterior denticles, apparently no second dorsal or anal fin, an amphistylic jaw suspension, and a distinctive triangular palatoquadrate. It is suggested that the species may represent a high-latitude, Late Devonian relict taxon

Long-term outcomes for transobturator tension-free vaginal tapes in women with urodynamic mixed urinary incontinence

We thank Dr D. Kramakar (DK) (Research Fellow—University of Aberdeen) for sending out the questionnaires and collating the responses. We thank Lindsey Grant (LG) for performing the independent data entry cross-check. A special gratitude is to all the women whose excellent cooperation made this study successful. The initial phase of this study (up to 3-year follow-up) was funded by the Henry Smith Charity. Dr Karmakar was funded by IUGA Clinical Fellowship Grant 2014.Peer reviewedPostprin

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

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

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

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

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