Evaluation of ground reaction forces produced by chickens walking on a force plate

Objective: To evaluate the use of a force plate as a method for objective gait analysis in adult poultry, to characterize ground reaction forces (GRFs) produced in adult chickens during normal walking, and to assess the variability of GRFs. Animals: 18 clinically normal 5-month-old Brown Leghorn hens Procedure: Vertical, craniocaudal, and mediolateral GRFs were measured as hens walked across a stan-dard force plate embedded in the middle of a runway. Results: All GRFs were significantly affected by speed, and variability was high. With increasing speed, overall stance time decreased, but the per-centage of stance time spent in braking or propulsion remained approximately equal. There was an overall increase in maximum propulsion force, which was produced at a greater rate over a shorter time; thus, propulsion integral ecreased. Maximum braking forces and braking integrals were variable, but the rate at which the forces were generated increased. Mediolateral forces were 2 to 3 times greater in hens than values that have been reported for other species. Conclusions and Clinical Relevance: A standard force plate can be used to objectively measure GRFs in walking adult hens; however, the large variation in the data suggests that the technique in its current form would be of limited clinical use. Overall, vertical and craniocaudal forces had similar characteristics to those of other species, whereas mediolateral forces were found to be much greater in chickens than for other species

Does teacher homework feedback matter to 6th graders' school engagement?: a mixed methods study

The effectiveness of homework on improving student academic achievement depends on several factors; for example, feedback provided by the teacher (i.e. grading) and student engagement are important moderators in this process. However, the relationships between the types of homework feedback commonly used by teachers and student school engagement have not yet been examined. Anchored in the Self-Determination Theory, this mixed methods sequential explanatory study investigated how five types of teacher homework feedback predict three dimensions of students' school engagement. The participants included 6th graders (N = 4288) and their mathematics teachers (N = 170). For this investigation, a quantitative phase was run, followed by a qualitative phase. The quantitative data were analyzed using multivariate multilevel regression models. The quantitative data showed positive relationships between five types of feedback and school engagement, albeit with different results at student and class levels. The findings showed small effect sizes. The qualitative data, based on a purposeful sampling, provided further insights regarding the low effect sizes that were found. Data were analyzed using thematic analysis. Four themes were identified as follows: homework at home and/or at the study center, perceived homework feedback types, school engagement, and school disaffection. Both data sets indicated directions to strengthen the benefits of homework feedback and to maximize students' learning. This research paper discusses practical implications as well as future research directions.This study was conducted at Psychology Research Centre (UID/PSI/01662/2013), University of Minho, and supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education through national funds and co-financed by FEDER through COMPETE2020 under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007653). The first author was supported by a PhD fellowship from the Portuguese Foundation for Science and Technology (FCT – SFRH/BD/95341/2013)