1,720,964 research outputs found
Experimental abrasion of water submerged bone: the influence of bombardment by different sediment classes on microabrasion rate
Full text linkData presented here demonstrates the utility of quantitative analysis of sediment-induced microabrasion on bone’s surface. Fresh sheep (Ovis aries) bone, acting as a human analogue, was bombarded by mobile sediments from silt, sand and gravel classes (ranging 20µm-3.35mm) in a series of flume-based experiments. Controlled bombardment produced unique abrasion patterns on bone which were recordable using scanning electron microscopy. Imaging abrasion at both x100 and x1000 magnifications allowed quantitative and qualitative distinction to be made concerning the sediment class that the bone was abraded by; bombardment by gravel classes caused abrasion to advance through cyclical cracking, whereas smoothing of bone’s surface occurred more frequently in sand and silt classes. A stepwise multi-linear regression model identified changes in sediment grain size (p<0.001), duration of exposure to abrasion (p<0.001), sphericity of the abrasive (p=0.002), and T value (abrasive force) (p=0.013) respectively, as the strongest rate limiting factors controlling microabrasion propagation. The methodology presented herein demonstrates analytical value by allowing diagnostic modifications to bone’s surface to be correlated with specific taphonomic processes. Data developed from flume-based experimentation was applied in four separate case studies; abrasion data recorded on bones recovered from different aquatic contexts, was linked to hydrological and marine seabed sediment data to demonstrate how documented microabrasion can reflect the different sedimentary contexts bone has passed through. In light of these results we suggest that a quantitative approach to analysing abrasion on bone retrieved from water has potential to allow remains’ submersion times and transport pathways to be established with a higher degree of resolution than is currently possible. The development of improved methodologies for the interpretation of submerged human bone is vital due to the increasing risks posed by flooding and coastal erosion to archaeological sites
A comparison of surface features on submerged and non-submerged bone using scanning electron microscopy
Full text linkSkeletal remains are excellent sources of information regarding the deceased individual and the taphonomic history of their body. However, the accuracy of this information is governed by our ability to interpret features on the surface of a bone. Little research in this respect has been carried out on remains found in aquatic environments. This study compares damage features created on the surface of modern and archaeological bone found in a seawater environment, to surface features present on unmodified bone, archaeological bone, pathological bone and burned bone. Results show that no similarities with regard to surface pores were identified between submerged modern bone and archaeological, pathological and burned bone. Similarities were seen between submerged and dry archaeological bones. Thus it is argued that the misinterpretation of the taphonomic history of isolated bones recovered from bodies of water should be avoidable in the forensic context
The abrasion of modern and archaeological bones by mobile sediments: the importance of transport modes.
No full textFresh, weathered, archaeological and fossilized bones were subjected to a series of abrasion experiments using fine sand in an annular flume in order to link bone-surface abrasion to flow regimes and sediment transport modes, compare these effects on bones of different states, and quantify the extent and types of wear occurring. Flow velocities were chosen to replicate the predominant transport modes of bedload, saltation and suspension.Comparative scanning electron microscopic image analysis was performed to assess the degree and type of wear occurring on each bone type for the different transport modes over a range of exposure periods from 24 to 72 h.These preliminary investigations have shown that both the amount and type of wear experienced was related to the bone type, duration of exposure and the mode of sediment transport with wear being the result of deformation, rather than cutting wear.The formation of scour pits in the sand bed on the upstream side of the bone samples significantly reduced wear, and appears to be an important control mechanism for impact related wear that has been overlooked until now
Flesh, Fire, and Funerary Remains from the Neolithic site of La Varde, Guernsey: Investigations Past and Present
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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
Towards a best practice for the use of active non-contact surface scanning to record human skeletal remains from archaeological contexts
Full text linkActive surface scanners emit light or a laser stripe to record the exterior surface of an object or landscape, providing results in three dimensions. The use of active surface scanners to record anthropological and archaeological contexts has increased within the last few years, creating a number of sub-contexts within these disciplines, and allowing a further development of certain applications, such as quantitative analysis, the use of replicas in education and museums, and the creation of digital databases archived in institutions. However with guidance, this paper aims to assess the advantages and disadvantages of active surface scanning and the potential for research with regards to the recording and analysis of human skeletal remains. The key advantages and uses identified include: quantitative digitisation, geometric morphometric studies, conservation, preservation, documentation, and reconstruction. However, surface scanning also has some limitations, including: cost, technological expertise, the need for a power source, computing requirements, and data size. Overall, the application of active surface scanning technology to archaeological skeletal remains will provide a vital digital archive that will serve to preserve the integrity of this fragile and finite resource for future generations. This is particularly important within the current developer-funded environment in which many skeletal collections, including those yielding unique or unusual pathological or morphological features, are re-buried, with only very limited time for 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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