Athletics

The purposes of this study were to investigate (1) the relationships between official distance and selected ground reaction measures during discus throwing; and (2) the relationships between selected ground reactions and selected lower extremity joint kinetics. Three high‐speed video cameras and three force plates were used to collect three‐dimensional videographic and force plate data in this study. An inverse dynamic model was used to determine the lower extremity kinetics. Multiple regression analyses were conducted to determine relationships of the selected kinematic and kinetic measures with the official distance. Official distance was significantly correlated with ground reaction forces on the left foot during the first single‐support phase, on the right foot during the second single‐support phase and delivery phase, and on the left foot during the delivery phase. Also, the right‐hip extension and internal rotation moments and left‐knee extension moment during the delivery phase were significantly correlated with official distance. These results suggest that discus throwers should drive vigorously forward during the first single‐support phase and increase the landing impact force on the right foot after flight. Also they should increase forward and rightward ground reaction force on the right foot and backward and vertical force on the left foot by powerful right‐hip extension and internal rotation and left‐knee extension during the delivery phase. These results provide critical information regarding the training of discus‐throwing techniques, and the direction of future biomechanical studies on this event.     

Effects of light refraction on the accuracy of camera calibration and reconstruction in underwater motion analysis

One of the most serious obstacles to accurate quantification of the underwater motion of a swimmer's body is image deformation caused by refraction. Refraction occurs at the water‐air interface plane (glass) owing to the density difference. Camera calibration‐reconstruction algorithms commonly used in aquatic research do not have the capability to correct this refraction‐induced nonlinear image deformation and produce large reconstruction errors. The aim of this paper is to provide a thorough review of: the nature of the refraction‐induced image deformation and its behaviour in underwater object‐space plane reconstruction; the intrinsic shortcomings of the Direct Linear Transformation (DLT) method in underwater motion analysis; experimental conditions that interact with refraction; and alternative algorithms and strategies that can be used to improve the calibration‐reconstruction accuracy. Although it is impossible to remove the refraction error completely in conventional camera calibration‐reconstruction methods, it is possible to improve the accuracy to some extent by manipulating experimental conditions or calibration frame characteristics. Alternative algorithms, such as the localized DLT and the double‐plane method are also available for error reduction. The ultimate solution for the refraction problem is to develop underwater camera calibration and reconstruction algorithms that have the capability to correct refraction.     

Governing knowledge in the scientific community: Exploring the role of retractions in biomedicine

Although the validity of knowledge is critical to scientific progress, substantial concerns exist regarding the governance of knowledge production. While research errors are as relevant to the knowledge economy as defects are to the manufacturing economy, mechanisms to identify and signal “defective” or false knowledge are poorly understood. In this paper, we investigate one such institution - the system of scientific retractions. We analyze the universe of peer-reviewed scientific articles retracted from the biomedical literature between 1972-2006 and comparing with a matched control sample in order to identify the correlates, timing, and causal impact of scientific retractions. This effort provides insight into the workings of a distributed, peer-based system for the governance of validity in scientific knowledge. Our findings suggest that attention is a key predictor of retraction - retracted articles arise most frequently among highly-cited articles. The retraction system is expeditious in uncovering knowledge that is ever determined to be false (the mean time to retraction is less than two years) and democratic (retraction is not systematically affected by author prominence). Lastly, retraction causes an immediate, severe, and long-lived decline in future citations. Conditional on the obvious limitation that we cannot measure the absolute amount of false science in circulation, these results support the view that distributed governance systems can be designed to uncover false knowledge relatively swiftly and to mitigate the costs that false knowledge for future generations of producers.     

From Biology to Mathematical Models and Back: Teaching Modeling to Biology Students,and Biology to Math and Engineering Students

We describe the development of a course to teach modeling and mathematical analysis skills to students of biology and to teach biology to students with strong backgrounds in mathematics, physics, or engineering. The two groups of students have different ways of learning material and often have strong negative feelings toward the area of knowledge that they find difficult. To give students a sense of mastery in each area, several complementary approaches are used in the course: 1) a “live” textbook that allows students to explore models and mathematical processes interactively; 2) benchmark problems providing key skills on which students make continuous progress; 3) assignment of students to teams of two throughout the semester; 4) regular one-on-one interactions with instructors throughout the semester; and 5) a term project in which students reconstruct, analyze, extend, and then write in detail about a recently published biological model. Based on student evaluations and comments, an attitude survey, and the quality of the students'' term papers, the course has significantly increased the ability and willingness of biology students to use mathematical concepts and modeling tools to understand biological systems, and it has significantly enhanced engineering students'' appreciation of biology.     

Living AnatoME: Teaching and learning musculoskeletal anatomy through yoga and pilates

Living AnatoME, a program designed in 2004 by two medical students in conjunction with the Director of Anatomy, teaches musculoskeletal anatomy through yoga and Pilates. Previously offered as an adjunct to the Gross Anatomy course in 2007, Living AnatoME became an official part of the curriculum. Previous research conducted on the program demonstrated its efficacy in providing relaxation and well-being to students who attended. In 2007, with all 144 gross anatomy students required to participate in a 1.5 hour Living AnatoME session on the upper and lower limbs, the impact of the program on students' comprehension of musculoskeletal anatomy was analyzed through the administration of 25-question pre- and post-tests, gauging knowledge in the following domains: upper limb, lower limb, muscle function, palpation, attachment/location, clinical correlate, and control (i.e., material not emphasized during the intervention). Analysis of postintervention tests revealed significant improvement in total Living AnatoME scores as well as in the domains of upper limb, muscle function, and palpation, indicating the possible efficacy of Living AnatoME in teaching anatomy. Performance on control questions also improved, although not significantly, which may indicate the role of other variables (e.g., additional study time) in increased performance.     

Evaluation of a teacher's classroom performance using the Florida performance measurement system

This article documents the use of the screening and formative observation instruments of the Florida Performance Measurement System; a system whose content validity, reliability, and predictive validity has been established for use in evaluating beginning, certified, and master teachers. A videotaped lesson, taught by the Secretary of Education, William Bennett, was coded and the data analyzed by reference to the norms of high school teacher performance in Florida. The specific strengths and areas of potential improvement of the teacher's performance are identified and constructive changes in performance suggested.