427 research outputs found

    The Middle to Upper Paleolithic transition in Siberia

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    Thesis (Ph.D.) University of Alaska Fairbanks, 1994This dissertation presents results of recent research in Siberia directed at (1) developing an accurate archaeological chronology for the mid-Upper Pleistocene of Siberia (chiefly through accelerator radiocarbon methods), and (2) defining and characterizing the region's Middle to Upper Paleolithic transition. Eleven Middle Paleolithic sites are now known from southwest Siberia. Relative age estimates of these cultural occupations range from the Last Interglacial (oxygen-isotope substage 5e, 128,000-118,000 years ago) to the mid-Middle Pleniglacial (oxygen-isotope stage 3,50,000-40,000 years ago). Associated lithic industries are Levallois and Mousterian. Middle Paleolithic interassemblage lithic variability is hinged on the differential production of Levallois points and Levallois flakes, and the intensity of side scraper reduction. Hominid remains from two sites, Denisova Peshchera and Peshchera Okladnikov, appear pre-modern and exhibit affinities to Neanderthals from southwest Asia. At least 15 sites have been assigned to the Siberian early Upper Paleolithic. Radiocarbon dates range from 42,000 to 30,000 years ago. Occupations at Kara-Bom (component IIa), Makarovo-4, and Varvarina Gora predate the effective range of radiocarbon dating (40,000 years ago), and may be considerably older than radiocarbon dates suggest. Initial Upper Paleolithic industries are characterized by the detachment of blades from "flat-faced" parallel blade cores, the absence of Levallois techniques, the presence of bifacial and burin secondary reduction technologies, and tool kits with end scrapers, angle burins, wedges, gravers, bifacial knives, and slender retouched points on blades. Also occurring for the first time are worked bone, ivory, and antler points, awls, and needles, pendants and other items of personal adornment, and rare examples of mobiliary art. Diagnostic hominid fossils are absent. The Middle to Upper Paleolithic transition involved dramatic and multi-faceted changes in tool technologies and tool forms. Patterns of change are discrete rather than discontinuous; no transitional industries have been identified. Stratigraphic evidence indicates rapid succession from one technocomplex to the other. This evidence supports population replacement rather than continuity for the origins of the Siberian Upper Paleolithic. Whether this event also signals the appearance of modern humans in this and surrounding areas of inner Asia must await additional hominid fossil discoveries

    Masterov Kliuch and the Early Upper Palaeolithic of the Transbaikal, Siberia

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    In 1996, archaeological excavations were conducted at the Masterov Kliuch site, located east of Lake Baikal, Siberia. Three archaeological components were uncovered, all occurring in colluvial deposits. The two lower components (I and II) are Palaeolithic in age and character. Component I is an early Upper Palaeolithic industry dated to 32,500-30,000 years ago (B.P.), and is in a primary context. Component II is undated but is also assignable to the early Upper Palaeolithic based on typology, although it appears to have been redeposited. Artifact assemblages from these two components are blade-based and include retouched blades and flakes, knives, denticulates, end scrapers, gravers, and burins. Component III represents a Bronze Age occupation dated to around 2900 B.P. The Palaeolithic industries at Masterov Kliuch are technologically/typologically similar to other initial Upper Palaeolithic industries in Siberia, and appear to represent some of the easternmost manifestations of an early Upper Palaeolithic technocomplex that spanned inner Asia from Uzbekistan to the Transbaikal between about 42,000 and 30,000 B.P. Our findings have further implications for Upper Palaeolithic research in northern Asia, especially regarding site formation processes and hunter-gatherer raw material procurement. First, like Masterov Kliuch, most early Upper Palaeolithic sites across northern Asia lie in colluvial settings and may not be in pristine, primary contexts, so that interpretations of stone features such as hearths or dwellings may be suspect. Second, study of the Masterov Kliuch lithic industries indicates that huntergatherers exclusively utilized local lithic resources in the manufacture of tools, and that raw material procurement strategies were embedded within other subsistence pursuits. This pattern of local, embedded raw material procurement is seen in virtually all other early Upper Palaeolithic sites in Siberia, while "logistical," longdistance procurement strategies, characteristic of the early Upper Palaeolithic of western Eurasia, did not appear in Siberia until much later in time, after about 25,000 B.P. KEYWORDS: Siberia, early Upper Palaeolithic, geoarchaeology, lithic technology, raw material procurement

    Oceanic Controls on the Mass Balance of Wilkins Ice Shelf, Antarctica

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    Several Antarctic Peninsula (AP) ice shelves have lost significant fractions of their volume over the past decades, coincident with rapid regional climate change. Wilkins Ice Shelf (WIS), on the western side of the AP, is the most recent, experiencing a sequence of large calving events in 2008 and 2009. We analyze the mass balance for WIS for the period 1992-2008 and find that the averaged rate of ice-shelf thinning was similar to 0.8 m a(-1), driven by a mean basal melt rate of \u3c w(b)\u3e = 1.3 +/- 0.4 m a(-1). Interannual variability was large, associated with changes in both surface mass accumulation and \u3c w(b)\u3e. Basal melt rate declined significantly around 2000 from 1.8 +/- 0.4 m a(-1) for 1992-2000 to similar to 0.75 +/- 0.55 m a(-1) for 2001-2008; the latter value corresponding to approximately steady-state ice-shelf mass. Observations of ocean temperature T obtained during 2007-2009 by instrumented seals reveal a cold, deep halo of Winter Water (WW; T approximate to - 1.6 degrees C) surrounding WIS. The base of the WW in the halo is similar to 170 m, approximately the mean ice draft for WIS. We hypothesize that the transition in \u3c w(b)\u3e in 2000 was caused by a small perturbation (similar to 10-20 m) in the relative depths of the ice base and the bottom of the WW layer in the halo. We conclude that basal melting of thin ice shelves like WIS is very sensitive to upper-ocean and coastal processes that act on shorter time and space scales than those affecting basal melting of thicker West Antarctic ice shelves such as George VI and Pine Island Glacier

    Paleogenomics. Genomic structure in Europeans dating back at least 36,200 years.

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    The origin of contemporary Europeans remains contentious. We obtained a genome sequence from Kostenki 14 in European Russia dating from 38,700 to 36,200 years ago, one of the oldest fossils of anatomically modern humans from Europe. We find that Kostenki 14 shares a close ancestry with the 24,000-year-old Mal'ta boy from central Siberia, European Mesolithic hunter-gatherers, some contemporary western Siberians, and many Europeans, but not eastern Asians. Additionally, the Kostenki 14 genome shows evidence of shared ancestry with a population basal to all Eurasians that also relates to later European Neolithic farmers. We find that Kostenki 14 contains more Neandertal DNA that is contained in longer tracts than present Europeans. Our findings reveal the timing of divergence of western Eurasians and East Asians to be more than 36,200 years ago and that European genomic structure today dates back to the Upper Paleolithic and derives from a metapopulation that at times stretched from Europe to central Asia.GeoGenetics members were supported by the Lundbeck Foundation and the Danish National Research Foundation (DNRF94). ASM was supported by the Swiss National Science Foundation (PBSKP3_143529). Research on the archaeological background by PRN was supported by a MC Career Integration Grant (322261).This is the accepted manuscript. The final version is available from Science at http://www.sciencemag.org/content/346/6213/1113.short

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Search for stop and higgsino production using diphoton Higgs boson decays

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    Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass

    Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

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    The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

    Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

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    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV
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