Students' ontological security and agency in science education - an example from reasoning about the use of gene technology

This paper reports on a study of how students' reasoning about socioscientific issues is framed by three dynamics: societal structures, agency and how trust and security issues are handled. Examples from gene technology were used as the forum for interviews with 13 Swedish highschool students (year 11, age 17–18). A grid based on modalities from the societal structures described by Giddens was used to structure the analysis. The results illustrate how the participating students used both modalities for 'Legitimation' and 'Domination' to justify positions that accept or reject new technology. The analysis also showed how norms and knowledge can be used to justify opposing positions in relation to building trust in science and technology, or in democratic decisions expected to favour personal norms. Here, students accepted or rejected the authority of experts based on perceptions of the knowledge base that the authority was seen to be anchored in. Difficulty in discerning between material risks (reduced safety) and immaterial risks (loss of norms) was also found. These outcomes are used to draw attention to the educational challenges associated with students' using knowledge claims (Domination) to support norms (Legitimation) and how this is related to the development of a sense of agency in terms of sharing norms with experts or with laymen.Web of Scienc

Design and Evaluation of the Initial 50th Percentile Female Prototype Rear Impact Dummy, BioRID P50F–Indications for the need of an additional dummy size

The objective of this study was to present the design of a prototype rear impact crash test dummy, representing a 50th percentile female, and compare its performance to volunteer response data. The intention was to develop a first crude prototype as a first step toward a future biofidelic 50th percentile female rear impact dummy. The current rear impact crash test dummy, BioRID II, represents a 50th percentile male, which may limit the assessment and development of whiplash protection systems with regard to female occupants. Introduction of this new dummy size will facilitate evaluation of seat and head restraint (HR) responses in both the average sized female and male in rear impacts. A 50th percentile female rear impact prototype dummy, the BioRID P50F, was developed from modified body segments originating from the BioRID II. The mass and rough dimensions of the BioRID P50F is representative of a 50th percentile female. The prototype dummy was evaluated against low severity rear impact sled tests comprising six female volunteers closely resembling a 50th percentile female with regard to stature and mass. The head/neck response of the BioRID P50F prototype resembled the female volunteer response corridors. The stiffness of the thoracic and lumbar spinal joints remained the same as the average sized male BioRID II, and therefore likely stiffer than joints of an average female. Consequently, the peak rearward angular displacement of the head and T1, and the rearward displacement of the T1, were lesser for the BioRID P50F in comparison to the female volunteers. The biofidelity of the BioRID P50F prototype thus has some limitations. Based on a seat response comparison between the BioRID P50F and the BioRID II, it can be concluded that the male BioRID II is an insufficient representation of the average female in the assessment of the dynamic seat response and effectiveness of whiplash protection systems

Road safety: the average male as a norm in vehicle occupant crash safety assessment

This review addresses how women and men are represented in regulatory tests conducted to assess adult occupant safety in vehicles. Injury statistics show that protection in the event of a crash is lower for females than males. Still, vehicle crash safety assessment for adult occupants is only using the average sized male to represent the entire adult population, while the average sized female is not represented. In order to enable car manufacturers and road safety regulators to safeguard that females benefit equally from crash safety measures as males, it is necessary to develop new dedicated occupant models. These new models must represent the female part of the population, i.e. crash test dummies and human body models representing the average female. New female models would, together with their male equivalents, make it possible to identify the vehicle occupant safety systems which provide the best safety features for both females and males

Kinematics Evaluation of Female Head-Neck Model with Reflexive Neck Muscles in Low-Speed Rear Impact

This study highlights the importance of evaluating active model performance in different configurations. This study has shown that additional development of the ViVA OpenHBM must be done before being used in the development and assessement of vehicle occupant safety. This is especially relevant before using the model to conduct accident reconstructions and whiplash injury predictions

Comparison of control strategies for the cervical muscles of an average female head-neck finite element model

Objective: ViVA OpenHBM is the first open-source Human Body Model (HBM) for crash safety assessment. It represents an average size (50th percentile) female and was created to assess whiplash protection systems in a car. To increase the biofidelity of the current model, further enhancements are being made by implementing muscle reflex response capabilities as cervical muscles alter the head and neck kinematics of the occupant during low-speed rear crashes. The objective of this study was to assess how different neck muscle activation control strategies affect head-neck kinematics in low-speed rear impacts.Methods: The VIVA OpenHBM head-neck model, previously validated to PMHS data, was used for this study. To represent the 34 cervical muscles, 129 beam elements with Hill-type material models were used. Two different muscle activation control strategies were implemented: a control strategy to mimic neural feedback from the vestibular system and a control strategy to represent displacement feedback from muscle spindles. To identify control gain values for these controller strategies, parameter calibrations were conducted using optimization. The objective of these optimizations was to match the head linear and angular displacements measured in volunteer tests.Results: Muscle activation changed the head kinematics by reducing the peak linear displacements, as compared to the model without muscle activation. For the muscle activation model mimicking the human vestibular system, a good agreement was observed for the horizontal head translation.However, in the vertical direction, there was a discrepancy of head kinematic response caused by buckling of the cervical spine. In the model with a control strategy that represents muscle spindle feedback, improvements in translational head kinematics were observed and less cervical spinebuckling was observed. Although, the overall kinematic responses were better in the first strategy.Conclusions: Both muscle control strategies improved the head kinematics compared to the passive model and comparable to the volunteer kinematics responses with overall better agreement achieved by the model with active muscles mimicking the human vestibular syste

Dynamic Responses of Female Volunteers in Rear Impact Sled Tests at Two Head Restraint Distances

The objective of this study was to assess the biomechanical and kinematic responses of female volunteers with two different head restraint (HR) configurations when exposed to a low-speed rear loading environment. A series of rear impact sled tests comprising eight belted, near 50th percentile female volunteers, seated on a simplified laboratory seat, was performed with a mean sled acceleration of 2.1 g and a velocity change of 6.8 km/h. Each volunteer underwent two tests; the first test configuration, HR10, was performed at the initial HR distance ∼10 cm and the second test configuration, HR15, was performed at ∼15 cm. Time histories, peak values and their timing were derived from accelerometer data and video analysis, and response corridors were also generated. The results were separated into three different categories, HR10C (N = 8), HR15C (N = 6), and HR15NC (N= 2), based on: (1) the targeted initial HR distance [10 cm or 15 cm] and (2) whether the volunteers’ head had made contact with the HR [Contact (C) or No Contact (NC)] during the test event. The results in the three categories deviated significantly. The greatest differences were found for the average peak head angular displacements, ranging from 10\ub0 to 64\ub0. Furthermore, the average neck injury criteria (NIC) value was 22% lower in HR10C (3.9 m2/s2), and 49% greater in HR15NC (7.4 m2/s2) in comparison to HR15C (5.0 m2/s2). This study supplies new data suitable for validation of mechanical or mathematical models of a 50th percentile female. A model of a 50th percentile female remains to be developed and is urgently required to complement the average male models to enhance equality in safety assessments. Hence, it is important that future protection systems are developed and evaluated with female properties taken into consideration too. It is likely that the HR15 test configuration is close to the limit for avoiding HR contact for this specific seat setup. Using both datasets (HR15C and HR15NC), each with its corresponding HR contact condition, will be possible in future dummy or model evaluation

Optimization of Female Head–Neck Model with Active Reflexive Cervical Muscles in Low Severity Rear Impact Collisions

ViVA Open Human Body Model (HBM) is an open-source human body model that was developed to fill the gap of currently available models that lacked the average female size. In this study, the head–neck model of ViVA OpenHBM was further developed by adding active muscle controllers for the cervical muscles to represent the human neck muscle reflex system as studies have shown that cervical muscles influence head–neck kinematics during impacts. The muscle controller was calibrated by conducting optimizationbased parameter identification of published-volunteer data. The effects of different calibration objectives to head–neck kinematics were analyzed and compared. In general, a model with active neck muscles improved the head–neck kinematics agreement with volunteer responses. The current study highlights the importance of including active muscle response to mimic the volunteer’s kinematics. A simple PD controller has found to be able to represent the behavior of the neck muscle reflex system. The optimum gains that defined the muscle controllers in the present study were able to be identified using optimizations. The present study provides a basis for describing an active muscle controller that can be used in future studies to investigate whiplash injuries in rear impacts