48 research outputs found

    The RESET project: constructing a European tephra lattice for refined synchronisation of environmental and archaeological events during the last c. 100 ka

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    This paper introduces the aims and scope of the RESET project (. RESponse of humans to abrupt Environmental Transitions), a programme of research funded by the Natural Environment Research Council (UK) between 2008 and 2013; it also provides the context and rationale for papers included in a special volume of Quaternary Science Reviews that report some of the project's findings. RESET examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions (AETs) on the one hand, and of human dispersal and development on the other, with a focus on the Middle and Upper Palaeolithic periods. The period of interest is the Last Glacial cycle and the early Holocene (c. 100-8 ka), during which time a number of pronounced AETs occurred. A long-running topic of debate is the degree to which human history in Europe and the Mediterranean region during the Palaeolithic was shaped by these AETs, but this has proved difficult to assess because of poor dating control. In an attempt to move the science forward, RESET examined the potential that tephra isochrons, and in particular non-visible ash layers (cryptotephras), might offer for synchronising palaeo-records with a greater degree of finesse. New tephrostratigraphical data generated by the project augment previously-established tephra frameworks for the region, and underpin a more evolved tephra 'lattice' that links palaeo-records between Greenland, the European mainland, sub-marine sequences in the Mediterranean and North Africa. The paper also outlines the significance of other contributions to this special volume: collectively, these illustrate how the lattice was constructed, how it links with cognate tephra research in Europe and elsewhere, and how the evidence of tephra isochrons is beginning to challenge long-held views about the impacts of environmental change on humans during the Palaeolithic. © 2015 Elsevier Ltd.RESET was funded through Consortium Grants awarded by the Natural Environment Research Council, UK, to a collaborating team drawn from four institutions: Royal Holloway University of London (grant reference NE/E015905/1), the Natural History Museum, London (NE/E015913/1), Oxford University (NE/E015670/1) and the University of Southampton, including the National Oceanography Centre (NE/01531X/1). The authors also wish to record their deep gratitude to four members of the scientific community who formed a consultative advisory panel during the lifetime of the RESET project: Professor Barbara Wohlfarth (Stockholm University), Professor Jørgen Peder Steffensen (Niels Bohr Institute, Copenhagen), Dr. Martin Street (Romisch-Germanisches Zentralmuseum, Neuwied) and Professor Clive Oppenheimer (Cambridge University). They provided excellent advice at key stages of the work, which we greatly valued. We also thank Jenny Kynaston (Geography Department, Royal Holloway) for construction of several of the figures in this paper, and Debbie Barrett (Elsevier) and Colin Murray Wallace (Editor-in-Chief, QSR) for their considerable assistance in the production of this special volume.Peer Reviewe

    A note on Turkish–Arabic contact at phonological level

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    A novel approach in voltage transient technique for the measurement of electron mobility and mobility-lifetime product in CdZnTe detectors

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    In this study, a new measurement method based on voltage transients in CdZnTe detectors response to low energy photon irradiations is applied to measure the electron mobility (μe) and electron mobility-lifetime product (μτ)e in a CdZnTe detector.In the proposed method, the pulse rise times are derived from low energy photon response to 59.5 keV(241Am), 88 keV(109Cd) and 122 keV(57Co) γ-rays for the irradiation of the cathode surface at each detector for different bias voltages. The electron (μτ)e product was then determined by measuring the variation in the photopeak amplitude as a function of bias voltage at a given photon energy using a pulse-height analyzer. The (μτ)e values were found to be (9.6 ± 1.4)x10−3cm2 V−1 for 1000 mm3, (8.4 ± 1.6)x10−3cm2 V−1 for 1687.5 mm3 and (7.6 ± 1.1)x10-3 cm2 V−1 for 2250 mm3 CdZnTe detectors. Those results were then compared with the literature (μτ)e values for CdZnTe detectors.The present results indicate that, the electron mobility μe and electron (μτ)e values in CdZnTe detectors can be measured easily by applying voltage transients response to low energy photons, utilizing a fast signal acquisition and data reduction and evaluation. Keywords: CdZnTe, Electron mobility, Mobility-lifetime product, Transient pulse, Rise time, Charge Carrier, Digital pulse processin

    Shoshonitic volcanism of the Bodrum caldera (SW Turkey): Hybridization of enriched mantle-derived and crustal melts

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    International audienceBodrum Caldera, located at the southwestern tip of the Anatolian plate, comprises volcanic rocks formed by intrusive, effusive and explosive volcanic activity during Miocene. Volcanic rocks chemically belong to K-rich shoshonitic series and comprised of a range of compositions from absarokites to rhyolites with intrusive micromonzogabbros and micromonzonites. The least evolved magmatic rocks are the post-caldera micromonzogabbros. Blebs/droplets with different mineralogical/petrographical characteristics and resorbed xenocrystic glomerocrysts/cumulates comprised of feldspar and clinopyroxene in disequilibrium with the host rocks suggest that mixing between compositionally different magmas was an important process for the evolution of Bodrum volcanism. Especially shoshonites contain mixing and mingling textures probably occurred between monzogabbroic and more evolved monzonitic magmas. Fractional crystallization was limited to felsic (>60% SiO2) rocks where feldspar, pyroxene, biotite, apatite and zircon were the main fractionating phases. Trace element abundances indicate a garnet-bearing enriched mantle peridotite, resembling EM-1 with a modal assemblage of garnet, rutile, titanite and phlogopite, as the common mantle source rock. Non-modal fractional melting models exhibit that micromonzonites, absarokites and micromonzogabbros were derived from lower (1-3%), moderate (10-15%) and higher (>20%) degrees partial melting of an enriched mantle, respectively. Besides, monzonitic compositions can be produced by partial fusion of a subducting slab with hypothetical composition of 80% GLOSS and 20 % N-MORB. Basic-intermediate compositions can be produced by the mixing/mingling of the micromonzogabbroic and monzonitic magmas. Crustal assimilation and fractional crystallization of hybrid absarokitic melts can yield intermediate-to-felsic compositions of Bodrum shoshonitic series

    Effect of ondansetron in lower extremity bone surgery on morphine and tramadol consumption using patient controlled analgesia [Alt ekstremite kemik cerrahisinde hasta kontrollü analjezide ondansetronun tramadol ve morfin tüketimine etkisi]

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    PubMedID: 17457705In this study, we aimed to assess the effect of administration of ondansetron on morphine and tramadol consumptions. After approval by the ethics committee, 120 patients with ASA status I or II, who will undergo elective lower extremity surgery, were included in the study. Patients were randomly divided into 4 groups following the anesthesia induction. Group I received tramadol as PCA with an infusion of 0.3 mg/kg following a loading dose of 1.5 mg/kg administered 1 hour before the end of the surgery. Group II received ondansetron 0.1 mg/kg following induction of anesthesia, additionally. Group III received morphine as PCA with an infusion following a loading dose of 0.15 mg/kg administered 30 minutes before the end of surgery. Group IV received ondansetron 0.1 mg/kg following induction of anesthesia, additionally. Pain scores(VAS), nausea, vomitting and sedation scores, analgesic consumptions and adverse effects were recorded at 5th, 15th, 30th, 45th minutes and 4th, 8th, 12th and 24th hours postoperatively. Postoperative VAS, nausea, vomitting and sedation scores were similar among the groups. The analgesic consumption was found significantly higher at 4th, 8th, 12th and 24th hours in group II. No statistically significant difference was found in analgesic consumption between group III and IV at all times. We concluded that, ondansetron, when administered as nausea prophylaxis in patients receiving tramadol and morphine as PCA, did not effect morphine consumption whereas did increased tramadol consumption
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