Time-elapsed screw insertion with microCT imaging

Author version made available following 12 month embargo from date of publication (18 Dec 2015) in accordance with Publisher copyright policy. Licensed under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Time-elapsed analysis of bone is an innovative technique that uses sequential image data to analyze bone mechanics under a given loading regime. This paper presents the development of a novel device capable of performing step-wise screw insertion into excised bone specimens, within the microCT environment, whilst simultaneously recording insertion torque, compression under the screw head and rotation angle. The system is computer controlled and screw insertion is performed in incremental steps of insertion torque. A series of screw insertion tests to failure were performed (n=21) to establish a relationship between the torque at head contact and stripping torque (R2=0.89). The test-device was then used to perform step-wise screw insertion, stopping at intervals of 20%, 40%, 60% and 80% between screw head contact and screw stripping. Image data-sets were acquired at each of these time-points as well as at head contact and post-failure. Examination of the image data revealed the trabecular deformation as a result of increased insertion torque was restricted to within 1 mm of the outer diameter of the screw thread. Minimal deformation occurred prior to the step between the 80% time-point and post-failure. The device presented has allowed, for the first time, visualization of the micro-mechanical response in the peri-implant bone with increased tightening torque. Further testing on more samples is expected to increase our understanding of the effects of increased tightening torque at the micro-structural level, and the failure mechanisms of trabeculae

Predicting reading performance using expectancy formulas

This study compares actual performance as measured by a reading achievement test with expected performance as predicted by the reading expectancy scores

Challenging High Potential Students In Large Classes: A Hurdles Approach

A hurdles approach, where qualitatively different expectations are linked to higher grades is suggested as a way of challenging high performing students in large classes with extreme range in ability. Large classes and increasing range in student ability and preparedness as well as diverse student learning styles have made it difficult to design assignments and grading schemes which meet the needs of students in the large class environment. High potential students are particularly underserved in this context. Time considerations are also an issue, as large classes make reading student writing assignments impractical. Most instructors know the value of assignments that challenge students’ critical thinking skills, but many can simply no longer handle the workload and thus resort to no papers, no essay exams, and rely on only the multiple-choice exam. It is suggested that setting up a multiple hurdles approach to grading and assignments in classes can address these problems and issues. Properly worked out, this method can provide the challenge your top students’ need, the feedback that they deserve, satisfy your need to really challenge students, and address the reality of large classes. This paper outlines how to set up such a multiple hurdles system and make it work

Emotional Responses to Varying Sources of Interpersonal Rejection

Baumeister and Leary (1995) propose with their Need to Belong Theory that negative affect would occur upon the disruption of an existing or even potential social connection. The present paper presents two studies that sought to resolve past contradictory research by examining how rejection by various sources (romantic partners, family members, close friends, or strangers) impact the rejectee’s emotional responses. The first study, which used a recalled memory of rejection, yielded no significant differences in mood, need to belong, threat to the four fundamental needs, or state self-esteem for the different sources. However, the second study, which used imagined scenarios, found that the source of rejection had a significant effect on the rejectee’s levels of hurt feelings, sadness, and perceived level of rejection, indicating that the effects of rejection are influenced by the relationship people have with their rejecters. This has many implications on how we understand relational dynamics and rejection

Perceptual Motor Match: Impact of Two Motor Training Programs

Purpose. The purpose of the study was to compare the impact of two motor training programs upon a selected perceptual motor task, verbal intelligence and motivation of kindergarten children. (Abstract shortened.

Perceptual Motor Match: Impact of Two Motor Training Programs

Purpose. The purpose of the study was to compare the impact of two motor training programs upon a selected perceptual motor task, verbal intelligence and motivation of kindergarten children. (Abstract shortened.