Browsing by Subject "fluted"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item A Behavioral Analysis of Clovis Point Morphology Using Geometric Morphometrics(2012-02-14) Smith, Heather LynnThis thesis presents an investigation into Paleoindian projectile-point morphology. A goal of this research is to determine if evidence of a normative cultural manufacturing protocol can be identified on Clovis projectile points which can then be used to address research questions concerning Clovis point variability, and ultimately, the spread of this tool-form across North America. This paper addresses obstacles to behavioral investigations of stone tool morphology such as the effects of resharpening and raw material type on tool shape. I argue that a culturally normative process of manufacture was maintained throughout the life-history of Clovis projectile points which translated into a specific shape maintained to the time of exhaustion and discard. As an analytical tool, this study utilizes the geometric morphometric method to retain the geometry of each artifact throughout analysis by focusing on spatial covariation among landmarks uniformly found on each tool. This thesis investigates variability in 123 fluted projectile points from 23 archaeological sites in North America which met criteria meant to control for security of context in the archaeological record. Principle components describing the shape-variability inherent in this data-set were generated using geometric morphometrics and multivariate statistical analyses were employed to identify major factors of variability. This research concluded that Clovis projectile-point shape was determined by normative cultural behavior maintained throughout the life of the artifact and not the result of raw material type or resharpening processes. Therefore, the projectile-point variability found to be geographically patterned provided evidence of Paleoindian movement and the spread of tool form. Multivariate analysis of variance determined that a regional trend in variability was present. The distribution of within-site variance suggested that artifacts from sites in the West were very homogeneous while artifacts from Eastern sites were more variable. The multivariate cluster and discriminant function analyses also demonstrated a closer affinity between artifacts in the Southwest and Northwest than either has with the Northeast. The similarities in projectile point morphology between the Southwest and Northwest regions suggest movement beginning with a Southwest point of origin from which Pleistocene peoples may have carried their fluted point technology north and east.Item Stability and Three-Dimensional Analysis of Bone Formation in Longitudinally Fluted Miniscrew Implants(2014-04-22) Truong, An VanThe purpose of the present study is to evaluate the effects of longitudinal flutes on mini-screw implant (MSI) bone healing and stability. Using 11 skeletally mature New Zealand White rabbits, 33 longitudinally fluted and 33 non-fluted MSIs were placed and immediately loaded with 100g using NiTi coil springs. Insertion torque values were obtained for each MSI that was placed; removal torque values were obtained for 28 MSIs that had been in place for 6 weeks and 20 MSIs that had been in place for 2 weeks. The bone volume fraction surrounding the implant 6-to-24 ?m, 24-to-42 ?m, and 42-60 ?m from the MSI surface using micro-computed tomography with an isotropic resolution of 6 ?m. The success rate was 97%, with both the fluted and non-fluted MSIs each having one failure. Mean insertion torque was slightly higher for fluted MSIs (3.98 N cm ?0.24) compared to non-fluted MSIs (3.95 N cm ?0.24), but the difference was not statistically significant (p=.930). After 6 weeks, removal torque values were significantly (p=.008) higher for the fluted (3.42 N cm ?0.26) than non-fluted (2.49 N cm ?0.20) MSIs. After 2 weeks, removal torque values were higher for fluted (2.87 N cm ?0.22) than non-fluted MSIs (2.75 N cm ?0.22), but the difference was not statistically significant (p=.702). After six weeks, bone volumes of the 6-24 ?m, 24-to- 42 ?m, and 42-to-60 ?m layers were significantly (p<.05) greater for the non-fluted than fluted MSIs. After two weeks, bone volume of three layers were also significantly (p<.05) greater for the non-fluted than fluted MSIs. Fluted and non-fluted 3 mm long MSIs can have very high success rates, even with all maximum insertion torque values being less than 6.2 N cm. Adding longitudinal flutes to 3 mm MSIs increases their removal torque by 37% after 6 weeks, despite the fact that there was less bone surrounding the fluted than non-fluted MSIs.