The effect of acceleration signal processing for head impact numeric simulations

Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modeling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8–30g) and rotational measures (1000–4000 rad/s²), but little effect on the finite element strain result (approximately 2–6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters.     

In search of systemic innovation for sustainable development: A design praxis emerging from a decade of social learning inquiry

Processes of designing for systemic innovation for sustainable development (SD) through the lens of three long-term case studies are reported. All case studies, which originated from the SLIM (Social Learning for the Integrated Management and Sustainable Use of Water at Catchment Scale) Project, funded within the EU Fifth Framework Program (2001–2004), constitute inquiry pathways that are explored using a critical incident approach. The initial starting conditions for each inquiry pathway are compared; significant pathway dependencies are identified which foster the development of social learning processes locally, but constrain their uptake and embedding across the wider system of interest. In the first case study, in England & Wales, promising developments in the application of social learning approaches to river basin planning over an initial 3-year period were subsequently marginalised, only to resurface towards the end of the 10-year period of study. In the second, South African case study, significant spaces for social learning and innovation in integrated water resources management were opened up over a five year period but closed down again, primarily as the result of lack of policy support by national government. The third, Italian, case study was designed to assess options for adapting to climate change by opening up new learning spaces between researchers, stakeholders and policy makers. A case for investing in local level systemic innovation through social-learning praxis design approaches and in learning processes around well contextualised case-studies is supported. However, concomitant investment by policy makers in social learning as an alternative, but complementary, governance mechanism for systemic innovation for SD is needed.     

How Science Teachers DiALoG Classrooms: Towards a Practical and Responsive Formative Assessment of Oral Argumentation

Journal of Science Education and Technology - We present lessons learned from an ongoing attempt to conceptualize, develop, and refine a way for teachers to gather formative assessment evidence...     

Physiological Responses to Maximal Treadmill and Handweighted Exercise

Abstract

The purpose of this investigation was to compare the peak physiological responses among four protocols that employed different amounts of handweighted exercise in 16 males (aged 26.3 ± 4.1 years). The four protocols were (a) uphill treadmill running (UR; 3.36 m-s¹, 2.5% grade increase-3 min¹); (b) uphill treadmill walking while pumping 1.36kg handweights (HW) (UWHW; 1.79ms¹, 5.0% grade increase-3 min¹; (c) treadmill walking while pumping .91-kg HW (WHW; 1.79 m-s¹, 0% grade, .91kg HW increase-3 min¹); and (d) standing in place and pumping HW (SHW; arm work as described in WHW). It was hypothesized that the peak responses would be inversely proportional to the estimated muscle mass activated (i.e., UR = UWHW > WHW > SHW). Dependent variables included peak oxygen uptake (VO₂ peak), peak heart rate (HRpeak), peak ventilation (V_epeak), and peak respiratory exchange ratio (RERpeak). No differences were noted between UR and UWHW with respect to any of the dependent variables. All variables (except RERpeak) were greater (p < .01) in UR and UWHW than either WHW or SHW. RERpeak was greater (p < .01) in UR and UWHW than in WHW. VO₂peak and HRpeak were greater (p < .01) in WHW when compared to SHW. Mean VO₂peak was 97.5, 69.7, and 60% of UR for UWHW, WHW, and SHW, respectively. Therefore, walking and pumping handweights provides a maximal stimulus to the oxygen transport system.     

New Books Briefly Noted

Abstract

Little research has investigated the observational learning process from a developmental perspective. The purpose of this study was to extend previous research by considering two factors: performance versus learning and sequencing versus form scores. Children 'N = 60) comprising two age groups (5-0 to 6-11 and 8-0 to 9-11 years) were randomly assigned to verbal rehearsal only, model only, or model plus verbal rehearsal conditions. The task was a 6 part motor skill sequence in which proper sequencing and quality of form were assessed. A 2 × 3 × 4 (age group by model type by trial blocks) repeated measures MANOVA revealed a significant three-way interaction. Older children performed equally well under any of the model type conditions during both performance and learning. For younger children, a model plus rehearsal was superior to rehearsal only on sequence and form at performance and learning and superior to model only on sequence scores during the first two performance trial blocks. Model only and model plus rehearsal conditions were equally effective on form scores. These results suggest that age differences exist in the modeling of motor skills under conditions varying in model type, sequence and form scores, and performance and learning phases.     

A comparison of the capacity of ice hockey goaltender masks for the protection from puck impacts

Goaltenders in ice hockey are the only players that are on the ice for the entire game. Their position exposes them to impacts from collisions with other players, falls to the ice, and puck impacts. In competitive ice hockey leagues, head injuries resulting from puck impacts have been reported with some cases resulting in ending the player’s career. Considerable research has been conducted to assess the performance of hockey helmets; however, few have assessed the performance of goaltenders’ masks. The purpose of this study was to compare the capacity of four goaltenders’ masks for the protection from puck impact as measured by head acceleration and peak force. A Hybrid III headform was fitted with four different goaltender masks and impacted with a hockey puck in three locations at 25 m/s. The masks were found to vary in the level of protection they offered as the mask with the thickest liner resulted in lower forces than the thinnest mask for side impacts; however, the thinnest mask resulted in the lowest force for front impacts. Despite performance differences at specific locations, no one mask proved to be superior as peak acceleration and peak force values did not exceed the thresholds necessary for concussion.     

Sarah Bernhardt's first “farewell” tour, 1905‐06: Little rock,arkansas welcomes Camille

Between 1800 and 1918, Sarah Bernhardt toured America nine times. Although she received critical praise and large profits from extended runs in cities, she often performed in smaller towns between cities to help defray the expenses of touring. Bernhardt's performance of Camille in Little Rock, Arkansas on March 6, 1906 was hailed as “the greatest dramatic event in the history of Little Rock.” This study details the events of Bernhardt's visit, discussing its impact on the social and cultural life of the city.     

Application of analytical geometry to the form of gear teeth

Nearly all gear wheels manufactured today have teeth with a profile based on the involute of a circle. The story of how this particular curve gained such mundane prevalence can be traced back to the pioneering work of European natural philosophers, in particular Euler. It involves the application of analytical geometry to a real world engineering problem.