1,720,968 research outputs found
Reconstruire les anciennes traces du feu à travers des approches biomoléculaires : L'analyse des résidus organiques et des acides polycarboxyliques du benzène dans les sols, les sédiments et les restes carbonisés du Paléolithique
No full textThe entanglement of Pleistocene and Palaeolithic hominins with fire is a long and convoluted process, which requires the mobilisation of multiproxy approaches to unravel. While significant developments have been made in recent years, the molecular and organic dimensions of these investigations remain relatively underexplored. This thesis investigates the potential of organic residue (lipid biomarker) and benzene polycarboxylic acid (BPCA) analysis to reconstruct past fire traces through the analysis of (pyrogenic) organic matter. The key aspects explored include: (i) the origins of combustion residues (i.e., natural versus anthropogenic), (ii) fuel sources, (iii) combustion conditions, namely heat treatment temperatures, (iv) the function(s) of anthropogenic fires, (v) the spatial organisation of combustion residues and pyrotechnic behaviours, and (vi) the palaeoenvironmental conditions in which the combustion events occurred. The potential of lipid biomarker and BPCA analyses to reveal these facets of pyrotechnology is investigated through the study of combustion residues at the Palaeolithic sites of Les Bossats à Ormesson and La Grotte Bouyssonie. Prior to archaeological applications, the utility of the BPCA method is demonstrated through a proof-of-concept study using the BPChAr database, from which random forest algorithms for the prediction of heat treatment temperatures and precursor feedstock in unknown samples were developed. At the open-air site of Ormesson, investigations focus on extensive combustion residues overlying Middle Palaeolithic deposits to determine whether these combustion residues result from natural or anthropic actions. The findings support the null hypothesis: that these combustion residues are the result of a previously unknown wildfire in the Paris Basin region during MIS 5. This case study raises broader epistemological challenges regarding the equifinality of archaeometric and geochemical data used to differentiate natural and anthropogenic fires. At the cave site of La Grotte Bouyssonie, Aurignacian and Magdalenian combustion residues are analysed with the objective of elucidating human-environment relations, and continuity and change in Upper Palaeolithic pyrotechnology. Geochemical data support the significant contributions of higher terrestrial plants to soil organic matter, with fuel procurement strategies contingent upon environmental variability, and no evidence for the cooking of meat or the use of animal products (dung, bone) as fuel. This case study raises questions regarding the biases of anthracological and geochemical data for palaeoenvironmental reconstruction, as well as epistemological approaches to pyrotechnology when evidence for ‘specialised' fire functions are absent. The unique archaeological contexts in which these methodologies were applied enable nuanced reflections on the analytical and interpretive potential of these methods to reconstruct past fire traces, so critical to understanding the evolution of Palaeolithic pyrotechnology.La maîtrise du feu par les hominines du Pléistocène et du Paléolithique constitue un processus long et complexe, qui nécessite la mobilisation d'approches multiples pour être élucidé. Bien que des avancées significatives aient été réalisées ces dernières années, les dimensions moléculaires et organiques de ces recherches demeurent relativement peu explorées. Cette thèse examine le potentiel des analyses de résidus organiques (biomarqueurs lipidiques) et d'acides polycarboxyliques du benzène (BPCA) pour reconstruire les anciennes traces de feu à travers l'étude de la matière organique (pyrogène). Les principaux aspects abordés incluent : (i) l'origine des résidus de combustion (naturelle ou anthropique), (ii) les sources de combustible, (iii) les conditions de combustion, notamment les températures de traitement thermique, (iv) les fonctions des feux anthropiques, (v) l'organisation spatiale des résidus de combustion et des comportements pyrotechniques, et (vi) les conditions paléoenvironnementales dans lesquelles les événements de combustion ont eu lieu. Le potentiel des analyses de biomarqueurs lipidiques et de BPCA pour révéler ces différentes facettes de la pyrotechnologie est exploré à travers l'étude de résidus de combustion sur les sites paléolithiques des Bossats à Ormesson et de la Grotte Bouyssonie. Avant les applications archéologiques, l'utilité de la méthode BPCA est démontrée dans le cadre d'une étude de validation utilisant la base de données BPChAr, à partir de laquelle des algorithmes d'apprentissage aléatoire (« random forest ») ont été développés pour prédire les températures de traitement thermique et le type de biomasse d'origine dans des échantillons inconnus. Sur le site en plein air d'Ormesson, les recherches portent sur d'importants résidus de combustion recouvrant des dépôts du Paléolithique moyen, afin de déterminer si ces résidus sont d'origine naturelle ou anthropique. Les résultats soutiennent l'hypothèse selon laquelle ces résidus de combustion seraient issus d'un incendie de forêt jusqu'alors inconnu, survenu dans le Bassin parisien au cours du MIS 5. Cette étude de cas soulève des enjeux épistémologiques plus larges concernant l'équifinalité des données archéométriques et géochimiques utilisées pour différencier les feux d'origine naturelle et anthropique. À la Grotte Bouyssonie, les résidus de combustion aurignaciens et magdaléniens sont analysés afin d'éclairer les relations entre l'homme et l'environnement, ainsi que la continuité et les évolutions dans la pyrotechnologie du Paléolithique supérieur. Les données géochimiques mettent en évidence une contribution significative des plantes terrestres supérieures à la matière organique du sol, avec des stratégies d'approvisionnement en combustible dépendant de la variabilité environnementale, et aucune preuve de cuisson de la viande ni d'utilisation de produits animaux (fumier, os) comme combustible. Cette étude de cas soulève des questions sur les biais des données anthracologiques et géochimiques dans la reconstitution paléoenvironnementale, ainsi que sur les approches épistémologiques de la pyrotechnologie en l'absence de preuves de fonctions « spécialisées » du feu. Les contextes archéologiques singuliers dans lesquels ces méthodologies ont été appliquées permettent des réflexions nuancées sur le potentiel analytique et interprétatif de ces approches pour reconstituer les anciennes traces de feu, essentielles à la compréhension de l'évolution de la pyrotechnologie paléolithique
The Materiality of Perforated Human Teeth and Ivory Skeuomorphs in the European Upper Palaeolithic
No full textHundreds of grooved and/or perforated natural objects (e.g., talons, faunal teeth,
marine shells) have been recovered from diverse archaeological contexts across the global late
Middle to mid Upper Palaeolithic. These objects continue to provoke questions about their
significative meanings, and about how material engagement with these things brought about
transformations in the world. Perforated human teeth and ivory skeuomorphs (that mimic the
shape of other things, e.g., shell) are two intriguing but under-explored Upper Palaeolithic
phenomena which this paper examines through the intersections of Peircean semiotics,
Material Engagement Theory, and material perspectivism. Beyond their significative powers
of iconicity, it is argued that perforated human teeth wielded powerful indexical properties that
engendered certain semiotic conflations and co-habitations through matter. These processes
could give rise to new material lexicons, such as figurative representation in non-standard
media (i.e., skeuomorphy). The act of skeuomorphy provides the semiotic ground for the
negotiation of material-form relationships, of signification through matter, and of human and
non-human relationships with their environment on multiple spatial and temporal scales. In
sum, placing these often-separated artefact ‘classes’ in dialogue beseeches us to consider a
material-semiotic meshwork that is more relational and rhizomic than individualistic and
demarcated. The acquisition, manufacture, embodied display, and active engagement of and
with these material signs enabled the continuous negotiation and realisation of ontological
tenets such as the relationality of human and non-human beings (including things) and the
ability of situated activity to instantiate new materialities and realities
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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