305 research outputs found

    Reconstruction of MIS 5 climate in the central Levant using a stalagmite from Kanaan Cave, Lebanon

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    Lying at the transition between the temperate Mediterranean domain and subtropical deserts, the Levant is a key area to study the palaeoclimatic response over glacial–interglacial cycles. This paper presents a precisely dated last interglacial (MIS 5) stalagmite (129–84 ka) from the Kanaan Cave, Lebanon. Variations in growth rate and isotopic records indicate a warm humid phase at the onset of the last interglacial at ~ 129 ka that lasted until ~ 125 ka. A gradual shift in speleothem isotopic composition (125–122 ka) is driven mainly by the ή18O source effect of the eastern Mediterranean surface waters during sapropel 5 (S5). The onset of glacial inception began after ~ 122 ka, interrupted by a short wet pulse during the sapropel 4 (S4) event. Low growth rates and enriched oxygen and carbon values until ~ 84 ka indicate a transition to drier conditions during Northern Hemisphere glaciation

    Multi frequency evaporative cooling to BEC in a high magnetic field

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    We demonstrate a way to circumvent the interruption of evaporative cooling observed at high bias field for 87^{87}Rb atoms trapped in the (F=2, m=+2) ground state. Our scheme uses a 3-frequencies-RF-knife achieved by mixing two RF frequencies. This compensates part of the non linearity of the Zeeman effect, allowing us to achieve BEC where standard 1-frequency-RF-knife evaporation method did not work. We are able to get efficient evaporative cooling, provided that the residual detuning between the transition and the RF frequencies in our scheme is smaller than the power broadening of the RF transitions at the end of the evaporation ramp.Comment: 12 pages, 2 figure

    Geomorphological context and formation history of Cloggs Cave: What was the cave like when people inhabited it?

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    New research undertaken at Cloggs Cave, in the foothills of the Australian Alps, employed an integrated geological-geomorphological-archaeological approach with manifold dating methods and fine resolution LiDAR 3D mapping. Long-standing questions about the site's chronostratigraphy (e.g. the exact relationship between basal megafaunal deposits and archaeological layers), sedimentation processes and geomorphic changes were resolved. The cave's formation history was reconstructed to understand its changing morphology and morphogenic processes, and to clarify how these processes shaped the cave's deposits. Key findings include the identification of: 1) the geomorphological processes that caused the lateral juxtaposition of 52,000 year-old megafaunal and later occupational layers; 2) the existence of one and possibly two (now-buried) palaeo-entrance(s) that enabled now-extinct megafauna and extant large fauna to enter the cave, most likely via a free-roaming passage rather than a pit drop; 3) morphological changes to the cave during the time of the Old People, including the timing of changes to the inclination of palaeo-surfaces; and 4) modifications to stalactites, crushing of calcite formations for the manufacture of powder, construction of a stone arrangement, and movement of large limestone blocks by the Old People. Ultimately, these findings demonstrate that to properly understand what Cloggs Cave was like when the Old People visited the site requires the construction of a narrative that spans some 400 million years and the development of an approach capable of integrating the many scales and processes (e.g. geological, geomorphological, archaeological) that configured to shape the site

    Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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    Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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    Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

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    Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search

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    Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

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    Measurement of the mass difference between top quark and antiquark in pp collisions at root s=8 TeV

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    Measurement of the azimuthal anisotropy of Y(1S) and Y(2S) mesons in PbPb collisions at √S^{S}NN = 5.02 TeV

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    The second-order Fourier coefficients (υ2_{2}) characterizing the azimuthal distributions of ΄(1S) and ΄(2S) mesons produced in PbPb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV are studied. The ΄mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of 1.7 nb−1^{-1}. The scalar product method is used to extract the υ2_{2} coefficients of the azimuthal distributions. Results are reported for the rapidity range |y| < 2.4, in the transverse momentum interval 0 < pT_{T} < 50 GeV/c, and in three centrality ranges of 10–30%, 30–50% and 50–90%. In contrast to the J/ψ mesons, the measured υ2_{2} values for the ΄ mesons are found to be consistent with zero
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