1,720,986 research outputs found
Suidae (Mammalia, Artiodactyla) from the late Miocene hominoid locality of Alsótelekes (Hungary)
Full text linkThe Suidae from the late Miocene of Alsótelekes (northeastern Hungary, Borsod-Abaúj-Zemplén county) are described and assigned to Propotamochoerus palaeochoerus (Suinae) and cf. Parachleuastochoerus (Tetraconodontinae). The co-occurrence of these two taxa agrees with a reference to the early Vallesian (MN 9), as previously indicated from biochronological correlation of the small mammal fauna, and suggests the presence of woodland environments, with abundance of below-ground resources and direct access to water. This fits well with the diverse wetlands and riparian forests that characterized Lake Pannon ∼10 Ma, as documented in the geographically close site of Rudabánya. The convoluted taxonomy of European Tetraconodontinae is discussed
Stable Isotope and Trace Element Paleoecology of the Rudabánya II Fauna: Paleoenvironmental Implications for the Late Miocene Hominoid, Rudapithecus hungaricus
Full text linkThe Late Miocene extinction of great apes in Europe has generally been regarded as the consequence of environmental changes that occurred in correlation with global Late Miocene cooling. However, given the range of dietary and locomotor adaptations observed among the different hominoid genera it is unlikely that the same environmental factors can account for the decline of the entire group. To better understand the factors that influenced the extinction of European Miocene apes it is necessary to evaluate their paleoecology on a regional scale. This research utilizes stable carbon and oxygen isotope (δ13C and δ18O) and strontium/calcium (Sr/Ca) trace element ratios measured in fossil ungulate tooth enamel to reconstruct the paleoecology and paleoclimate of Rudabánya II (R. II), an early Late Miocene (~10 Ma) hominoid locality in northeastern Hungary. The fossiliferous deposits at R. II preserve abundant samples of the extinct great ape Rudapithecus hungaricus. Primary aims of this research include: 1) evaluating the types of habitats present in terms of forest canopy cover, 2) examining trophic niche dynamics among the diverse ungulate community, and 3) estimating key climatic variables including mean annual temperature (MAT), mean annual precipitation (MAP), and degree of seasonality. Stable isotope and Sr/Ca values indicate the presence of a heterogeneous wetland-forest environment, with a gradient of more open to closed canopy habitats. Significant differences in stable isotope and Sr/Ca values were observed among the sampled ungulate fauna, supporting the interpretation of resource specialization and partitioning. A MAP of 1030-1333 mm/yr, and a MAT of 14°C were calculated from the average δ13C and δ18O values of the equid Hippotherium intrans. Intra-tooth δ18O values revealed low amplitudes of variation indicating that seasonal changes in temperature and precipitation were relatively mild. The paleoenvironment that Rudapithecus inhabited was similar to that of contemporaneous hominoids in Western Europe, but strikingly different from that of hominoids in the Eastern Meditterranean. While adaptations to fallback feeding and efficient suspensory arboreality would have allowed Rudapithecus to endure some degree of environmental deterioration, the progressive restriction and fragmentation of humid wetland-forests following the retreat of Lake Pannon would have eventually led to its extinction.Ph.D
Phylogenetic, Ontogenetic, and Functional Implications of Hominoid Mandibular Corpus Shape Variation
Full text linkMandibular fragments are among the most commonly preserved elements in the primate fossil record. These specimens are often studied through linear measurements of mandibular corpus height and breadth, which are used to calculate mandibular robusticity (MR). Presently, the significance of mandibular corpus variation in both living and fossil hominoids remains unclear. Here, three separate analyses are conducted to develop and evaluate an alternative method to quantify hominoid mandibular corpus shape and to investigate the dietary, phylogenetic and ontogenetic significance of hominoid mandibular corpus shape variation in order to help interpret corpus shape variation in the primate fossil record. These analyses use landmarks and semilandmarks to capture the shape of the outline of the mandibular corpus in cross-section in a sample of extant great apes, corporal cortical bone distribution (CBD) in a sample of extant and fossil hominoids, and to assess ontogenetic changes in corpus shape and the relationship between these changes and molar crypt length, breadth and height in a sample of extant hominoids.
These results show that quantification and comparison of the shape mandibular corpus in cross-section is a preferred alternative to MR in studying the hominoid fossil record. Additionally, extant hominoids are found to have significant CBD shape differences that are phylogenetically significant and do not match morphological predictions based on diet. Investigation into ontogenetic changes in corpus shape shows clear differences in growth patterns among all three species prior to the emergence of M1, and finds a significant covariance between molar crypt form and corpus shape during the developmental stage marked by the emergence of M1.
This research is significant because it provides support for the hypothesis that hominoid mandibular corpus shape is influenced by the development of the molars in their crypts during development. These results also indicate that both corpus shape and corporal CBD shape are taxonomically and phylogenetically significant and do not match morphological predications based on diet in hominoids. Additionally, this research shows that quantification and comparison of the outline of the mandibular corpus is a preferred alternative to MR in studying the hominoid fossil record.Ph.D
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
The manual skills and cognition that lie behind hominid tool use
No full textTool use is an important aspect of being human that has assumed a central place in accounts of the evolutionary origins of human intelligence. This has inevitably focused a spotlight on any signs of tool use or manufacture in great apes and other non-human animals, to the relative neglect of skills that do not involve tools. The aim of this chapter is to explore whether this emphasis is appropriate. Could it be that we may learn as much about the origin of human intelligence from skilled manual behaviour in general? Suppose we take this broader view, accepting evidence from all manifestations of manual skill, what can we learn of the mental capacities of the great apes and ourselves? My own ultimate purpose is to use comparative evidence from living species to reconstruct the evolutionary history of the many cognitive traits that came together to make human psychology. The cognition of great apes is the obvious starting point, to trace the more primitive (i.e. ancient) cognitive aptitudes that are still important to us today. In this chapter, I focus on great ape cognition as it is expressed in manual skills, based on cognitive aspects of tool use and manufacture considered significant in the human evolutionary lineage
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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