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Ceri Shipton - One of the best experts on this subject based on the ideXlab platform.

  • biface Knapping skill in the east african acheulean progressive trends and random walks
    African Archaeological Review, 2018
    Co-Authors: Ceri Shipton
    Abstract:

    Over the 1.5-million-year duration of the Acheulean, there is considerable variation in biface finesse. It is not clear, however, if there is an improvement in biface Knapping ability over time, or if variation between sites is largely unrelated to their age. The diversity and duration of the East African Acheulean presents an opportunity to examine this issue. Variables that reflect difficult aspects of biface Knapping, and which were likely important goals for Acheulean hominins, were measured in order to assess skill. These variables—refinement (thinness), edge straightness, and symmetry—were compared across four East African Acheulean sites: Olduvai Gorge, Olorgesailie, Kariandusi, and Isinya. The influence of rock type, blank type, reduction intensity, aberrant scar terminations, and invasive flaking on these variables was assessed. Over relatively short timescales, confounding factors, including ones not possible to control for, tend to obscure any temporal signature in biface Knapping skill. However, over the vast timespan of the Acheulean at Olduvai Gorge, a temporal trend was indeed apparent. Possible factors influencing this trend include the invention of new Knapping techniques, the addition of adolescence as a life history stage, and evolving hominin cognition.

  • biface Knapping skill in the east african acheulean progressive trends and random walks
    African Archaeological Review, 2018
    Co-Authors: Ceri Shipton
    Abstract:

    Over the 1.5-million-year duration of the Acheulean, there is considerable variation in biface finesse. It is not clear, however, if there is an improvement in biface Knapping ability over time, or if variation between sites is largely unrelated to their age. The diversity and duration of the East African Acheulean presents an opportunity to examine this issue. Variables that reflect difficult aspects of biface Knapping, and which were likely important goals for Acheulean hominins, were measured in order to assess skill. These variables—refinement (thinness), edge straightness, and symmetry—were compared across four East African Acheulean sites: Olduvai Gorge, Olorgesailie, Kariandusi, and Isinya. The influence of rock type, blank type, reduction intensity, aberrant scar terminations, and invasive flaking on these variables was assessed. Over relatively short timescales, confounding factors, including ones not possible to control for, tend to obscure any temporal signature in biface Knapping skill. However, over the vast timespan of the Acheulean at Olduvai Gorge, a temporal trend was indeed apparent. Possible factors influencing this trend include the invention of new Knapping techniques, the addition of adolescence as a life history stage, and evolving hominin cognition.

Ignacio Torre - One of the best experts on this subject based on the ideXlab platform.

  • Spatial and orientation patterns of experimental stone tool refits
    Archaeological and Anthropological Sciences, 2019
    Co-Authors: Ignacio Torre, Tomos Proffitt, Nils Vanwezer, Alfonso Benito-calvo, Rafael Mora
    Abstract:

    Freehand and bipolar experimental Knapping of quartzite from Olduvai Gorge in Tanzania is used to conduct spatial analysis of artefact distributions using GIS techniques, and to investigate the orientation of refit lines using circular histograms. The aim of our study is to discern patterns that can be applied to the archaeological record in two domains, namely the identification of Knapping episodes and the utility of refitting line orientations in addressing post-depositional disturbance. Our spatial analysis shows that distinctive clustering patterns can be discerned according to Knapping stance, handedness and flaking technique. The circular dispersion of refit lines in the horizontal distribution of bipolar assemblages is strongly patterned, indicating that anisotropy of conjoining sets is inherent to pristine hammer-and-anvil Knapping episodes.

  • a comparative analysis of bipolar and freehand experimental Knapping products from olduvai gorge tanzania
    Quaternary International, 2016
    Co-Authors: Fergus Byrne, Adrian Arroyo, Tomos Proffitt, Ignacio Torre
    Abstract:

    Abstract This study aims to investigate the quantitative and qualitative differences between freehand and bipolar experimental Knapping products of quartzite from Olduvai Gorge, Tanzania. A series of blind analyses are undertaken in order to better understand the effect that Olduvai quartzite may have on both inter-analyst variation and analyst accuracy in the identification of bipolar Knapping products. This is followed by a comprehensive analysis of the morphology of experimental freehand and bipolar flakes and cores incorporating both traditional linear measurements as well as 2D geometric morphometric analysis; additionally, the validity of qualitative bipolar attributes are assessed in the differentiation between Knapping techniques. The results of this study highlight the analytical difficulties and the high levels of analyst subjectivity in identifying bipolar Knapping in Olduvai quartzite assemblages. Additionally, it is noted that the majority of morphometric measures of bipolar and freehand knapped products do not differ significantly and should not be used in isolation for recognition of these Knapping techniques. Instead, conservative analysis of qualitative bipolar traits on cores may offer better results in the identification of Knapping technique.

Nathalie J Bureau - One of the best experts on this subject based on the ideXlab platform.

  • the snapping iliopsoas tendon new mechanisms using dynamic sonography
    American Journal of Roentgenology, 2008
    Co-Authors: Melanie Deslandes, Raphael Guillin, Etienne Cardinal, Roger Hobden, Nathalie J Bureau
    Abstract:

    OBJECTIVE. The purpose of our study was to describe new mechanisms responsible for the snapping iliopsoas tendon using dynamic sonography.MATERIALS AND METHODS. We reviewed the video recordings obtained during dynamic sonography studies used to establish the diagnosis of 18 snapping iliopsoas tendons in 14 patients (nine females and five males; age range, 13–50 years) who presented clinically with either unilateral (n = 10) or bilateral (n = 4) snapping hips. During dynamic imaging, the transducer was positioned in a transverse oblique plane just above the hip joint parallel to the pubic bone. For all patients, the hip movement that generated the snapping consisted of bringing the hip from flexion–abduction–external rotation back to the neutral position.RESULTS. In 14 of 18 hips, the snapping was provoked by the sudden flipping of the iliopsoas tendon around the iliac muscle, allowing abrupt contact of the tendon against the pubic bone and producing an audible snap. Other causes of snapping iliopsoas tend...

Peter J Millett - One of the best experts on this subject based on the ideXlab platform.

  • scapulothoracic bursitis and snapping scapula syndrome a critical review of current evidence
    American Journal of Sports Medicine, 2015
    Co-Authors: Ryan J Warth, Ulrich J Spiegl, Peter J Millett
    Abstract:

    Background:Symptomatic scapulothoracic disorders, such as painful scapular crepitus and/or bursitis, are uncommon; however, they can produce significant pain and disability in many patients.Purpose:To review the current knowledge pertaining to snapping scapula syndrome and to identify areas of further research that may be helpful to improve clinical outcomes and patient satisfaction.Study Design:Systematic review.Methods:We performed a preliminary search of the PubMed and Embase databases using the search terms “snapping scapula,” “scapulothoracic bursitis,” “partial scapulectomy,” and “superomedial angle resection” in September 2013. All nonreview articles related to the topic of snapping scapula syndrome were included.Results:The search identified a total of 167 unique articles, 81 of which were relevant to the topic of snapping scapula syndrome. There were 36 case series of fewer than 10 patients, 16 technique papers, 11 imaging studies, 9 anatomic studies, and 9 level IV outcomes studies. The level of...

  • scapulothoracic bursitis and snapping scapula syndrome a critical review of current evidence
    American Journal of Sports Medicine, 2015
    Co-Authors: Ryan J Warth, Ulrich J Spiegl, Peter J Millett
    Abstract:

    Background:Symptomatic scapulothoracic disorders, such as painful scapular crepitus and/or bursitis, are uncommon; however, they can produce significant pain and disability in many patients.Purpose:To review the current knowledge pertaining to snapping scapula syndrome and to identify areas of further research that may be helpful to improve clinical outcomes and patient satisfaction.Study Design:Systematic review.Methods:We performed a preliminary search of the PubMed and Embase databases using the search terms “snapping scapula,” “scapulothoracic bursitis,” “partial scapulectomy,” and “superomedial angle resection” in September 2013. All nonreview articles related to the topic of snapping scapula syndrome were included.Results:The search identified a total of 167 unique articles, 81 of which were relevant to the topic of snapping scapula syndrome. There were 36 case series of fewer than 10 patients, 16 technique papers, 11 imaging studies, 9 anatomic studies, and 9 level IV outcomes studies. The level of...

Tomos Proffitt - One of the best experts on this subject based on the ideXlab platform.

  • Spatial and orientation patterns of experimental stone tool refits
    Archaeological and Anthropological Sciences, 2019
    Co-Authors: Ignacio Torre, Tomos Proffitt, Nils Vanwezer, Alfonso Benito-calvo, Rafael Mora
    Abstract:

    Freehand and bipolar experimental Knapping of quartzite from Olduvai Gorge in Tanzania is used to conduct spatial analysis of artefact distributions using GIS techniques, and to investigate the orientation of refit lines using circular histograms. The aim of our study is to discern patterns that can be applied to the archaeological record in two domains, namely the identification of Knapping episodes and the utility of refitting line orientations in addressing post-depositional disturbance. Our spatial analysis shows that distinctive clustering patterns can be discerned according to Knapping stance, handedness and flaking technique. The circular dispersion of refit lines in the horizontal distribution of bipolar assemblages is strongly patterned, indicating that anisotropy of conjoining sets is inherent to pristine hammer-and-anvil Knapping episodes.

  • a comparative analysis of bipolar and freehand experimental Knapping products from olduvai gorge tanzania
    Quaternary International, 2016
    Co-Authors: Fergus Byrne, Adrian Arroyo, Tomos Proffitt, Ignacio Torre
    Abstract:

    Abstract This study aims to investigate the quantitative and qualitative differences between freehand and bipolar experimental Knapping products of quartzite from Olduvai Gorge, Tanzania. A series of blind analyses are undertaken in order to better understand the effect that Olduvai quartzite may have on both inter-analyst variation and analyst accuracy in the identification of bipolar Knapping products. This is followed by a comprehensive analysis of the morphology of experimental freehand and bipolar flakes and cores incorporating both traditional linear measurements as well as 2D geometric morphometric analysis; additionally, the validity of qualitative bipolar attributes are assessed in the differentiation between Knapping techniques. The results of this study highlight the analytical difficulties and the high levels of analyst subjectivity in identifying bipolar Knapping in Olduvai quartzite assemblages. Additionally, it is noted that the majority of morphometric measures of bipolar and freehand knapped products do not differ significantly and should not be used in isolation for recognition of these Knapping techniques. Instead, conservative analysis of qualitative bipolar traits on cores may offer better results in the identification of Knapping technique.