1,721,194 research outputs found
Middle Pleistocene molluscan fauna from the Valle Giumentina (Abruzzo, Central Italy): Palaeoenvironmental, biostratigraphical and biogeographical implications
No full textPalaeoenvironmental reconstructions through the Middle Pleistocene sequence in the Valle Giumentina, located in the Abruzzo region of Central Italy, are discussed. The sampled sequence is 16 m thick and includes nine levels with Lower Palaeolithic industries. The lithostratigraphy shows fluvio-glacial sediments with interbedded colluvial deposits and volcanic tephras. Fine sediments are composed of calcareous sands and silts, most of them yielding well-preserved mollusc shells. Forty-five samples, at 10 cm resolution, yielded 45 taxa, which could be assigned to four biozones. The oldest (biozone VGM1) indicate an open environment, which becomes a closed forest landscape developing under temperate conditions (VGM2). After a decline of thermophilous species (VGM3), mollusc assemblages indicate a dry open environment typical of a glacial period (VGM4). All prehistoric occupation horizons occur during stable environmental episodes but under both temperate and cold climatic conditions. The molluscan succession is allocated to the Middle Pleistocene on the basis of the occurrence of Jaminia malatestae, a well-known Italian species, now extinct, as well as the similarity of the molluscan record to that of Case Picconetto, a well-dated site nearby. This attribution is supported by three tephra layers dated by 40Ar/39Ar at 556 ± 6, 531 ± 5 and 456 ± 2 ka. The sequence is correlated with marine isotopic stages 14, 13 and 12. Four species of land snail (Azeca goodalli, Ruthenica filograna, Pagodulina pagodula, Nesovitrea hammonis) occur beyond their modern range and are therefore of biogeographical interest. These snails are western and central European in origin and their presence within the Valle Giumentina deposits highlight a north-south gradient of colonization during Pleistocene interglacial periods
Conférence : La géochronologie : une science relative et absolue
No full textDans le cadre de l'exposition "Néandertal fait son chaud : 200 000 ans de changements climatiques et culturels", Arkéos propose le 27 avril 2024 une conférence de Jean-Jacques Bahain (Muséum national d'Histoire naturelle), sur la géochronologie : une science relative et absolue. Informations complémentaires : Conférence : La géochronologie : une science relative et absolueDate : le 27 avril 2024Lieu : Arkéos. Musée-Parc archéologique4401 route de Tournai59500 Doua
Liste des relecteurs sollicites en 2009 (articles publiés ou refusés)
Full text linkValérie ANDRIEU-PONEL, Pierre ANTOINE, Alain ARGANT, Patrick AUGUSTE, Jean-Jacques BAHAIN, Ronald Van BALEN, Stéphane BONNET, Jean-Philip BRUGAL, Michel CAMPY, Jean-Christophe CASTEL, Christine CHAUSSE, Isabelle COJAN, Jean-Pierre COUTARD, Sylvie COUTARD, Evelyne CRÉGUT, Marc DURAND, Robert ETIENNE, Philippe FERNANDEZ, Philip GIBBARD, Christophe GRIGGO, Francis GROUSSET, Jean-Luc GUADELLI, Claude GUERIN, Bernard HALLEGOUET, Dominique HARMAND, Vincent LEBRETON, Jean-Luc LOCHT, Jean-Jacques MAC..
Contact
No full textPrésident - Franck BASSINOT Laboratoire des Sciences du Climat et de l'Environnement (CEA/CNRS/UVSQ), Domaine du CNRS – bâtiment 12, Avenue de la Terrasse 91198 GIF-SUR-YVETTE cedex e-mail : [email protected]ésident - Jean-Jacques BAHAIN Département de Préhistoire du Muséum national d'Histoire naturelle, 1 rue René Panhard 75013 PARIS e-mail : [email protected] Secrétaire - Secretary Sylvie COUTARD INRAP Nord-Picardie, 32 Avenue de l'Etoile du Sud, 80440 GLISY e-mail : sylvie.coutard..
San Bernardino Cave (Italy) and the appearance of Levallois technology in Europe: results of a radiometric and technological reassessment.
No full textThe introduction of Levallois technology in Europe marked the transition from the Lower to the early Middle Paleolithic. This new method of flake production was accompanied by significant behavioral changes in hominin populations. The emergence of this technological advance is considered homogeneous in the European archaeological record at the Marine isotopic stage (MIS) 9/MIS 8 boundary. In this paper we report a series of combined electron spin resonance/U-series dates on mammal bones and teeth recovered from the lower units of San Bernardino Cave (Italy) and the technological analyses of the lithic assemblages. The San Bernardino Cave has yielded the earliest evidence of Levallois production on the Italian Peninsula recovered to date. In addition to our results and the review of the archaeological record, we describe the chronological and geographical differences between European territories and diversities in terms of technological developments. The belated emergence of Levallois technology in Italy compared to western Europe corresponds to the late Italian Neanderthal speciation event. The new radiometric dates and the technological analyses of San Bernardino Cave raise the issue of the different roles of glacial refugia in the peopling and the spread of innovative flaking strategies in Europe during the late Middle Pleistocene
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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