An in vitro model of Rapid Acceleration Impact (RAI) Injury was used to study the effects of multiple impact (220 g/impact, 3-5 sec intervals) trauma on cultures of murine CNS cells. Investigations with spinal cord cultures showed that 1) multiple impacts delivered tangential to the plane of cell growth caused neuronal death (12% after 3 impacts to 46% after 10 impacts); 2) multiple impacts delivered normal to the plane of cell growth were much less effective (8% dead after 10 impacts); 3) most neuronal death occurred within 15 minutes after injury 4) morphological changes observed included increased nuclear prominence and somal swelling; and 5) pretreatment with ketamine (0.1mM) reduced cell death from 51 to 14% and reduced somal swelling. Identical studies performed on cortical cultures revealed minimal differences between the two tissues in their response to multiple tangential impacts.

Title: The Effects of a warm-up on the performance of football players Objectives: The comparison of influence of two types of warm-up before and after a physical activity on performance of U19 football players. Testing of subsequent post-warm-up performance focused on acceleration, explosive power and agility. Methods: In this empirical-theoretical thesis, a total of twenty-four U19 football players, divided in two experimental groups, is tested. The players within each group undertook either a complete dynamic warm-up or a shorter warm-up without the dynamic component. The performance was tested after the warm-up utilizing four tests - an acceleration run test on 30 m, a standing long jump, a foul throw and a shuttle run. The same tests were conducted again after an interlaid physical activity. The same procedure was repeated after a week when the two groups swapped the warm-up methods. Statistical analyses were employed to evaluate the results. Results: The hypothesis 1, assuming a positive effect of a complete dynamic warm-up on the performance before the physical activity was on one hand supported in the acceleration run on 30 m and the foul throw. On the other hand, no distinctive advantage of a complete dynamic warm-up was observed for the standing long jump and the shuttle run. Hypothesis 2...

A footbridge in Slussen is planned to be built and will connect the area of Gamla Stan with Sodermalm. As an increasing number of footbridges with large span tend to become more flexible and light these days, the corresponding dynamic problems due to decreased stiffness and mass draw much more attention. Specifically speaking, reduced stiffness and mass lead to smaller natural frequencies, which make the structure more sensitive to pedestrian-induced loading, especially in lateral direction. Fortunately, in this master thesis, only the vibration in vertical direction is focused due to that the footbridge in Slussen project uses enough lateral bracings to make sure that the safety of lateral vibration is kept at an acceptable level. In order to analyze dynamic response of the footbridge, the real footbridge structure is converted into a FE model by the commercial software LUSAS. In this thesis, four different kinds of critical standards are introduced, which are Sétra [8], Swedish standard Bro 2004 [9], ISO 10137 [5] and Eurocode respectively. By comparing these four criteria, Sétra and Eurocode are finally chosen to be the standard and guidelines for this project. They give the basic theories about how to model the pedestrian loading and provide critical values to check the accelerations in both vertical and lateral direction. By using FE software LUSAS, natural frequencies of the footbridge and the corresponding mode shapes can be calculated directly. Then, according to these results and relevant theories introduced by Sétra, the pedestrian loading can be modeled and the acceleration response of any specific mode can be obtained as well. Finally, based on the worst case with excessive acceleration, the methods to reduce dynamic response will be presented. Commonly, there are two ways to reduce acceleration response. One method is to increase the stiffness of the structure. However, the increased stiffness is always accompanied with increased mass of the structure. Because of this reason, the other way that installing dampers is widely used in recent years. In this thesis, the tuned mass dampers (TMDs) are introduced in detail as well as the information about the design principles of it. With important parameters known, TMDs can be added to the model to check how the accelerations can be reduced.

The purpose of this thesis is to analyze a golfer’s movement and provide the feedback related to the golfer’s skill with the simple and novel ways. A golfer can easily measure golf swings and get feedback based on his performance using an Android smart phone without expensive or complicated devices. In this thesis, we designed and implemented an Android application using an accelerometer sensor to analyze swing data for identifying critical points and to give various kinds of feedback based on the data. The feedback helps golfers to understand their swing patterns, timing and speed so it makes them improve their skills.

As space missions continue to increase in complexity, the operational capabilities and amount of gathered data demand ever more advanced systems. Currently, mission capabilities are often constrained by the link bandwidth as well as onboard processing capabilities. A large number of commands and complex ground station systems are required to allow spacecraft operations. Thus, methods to allow more efficient use of the bandwidth, computing capacity and increased autonomous capabilities are of strong research interest. Artificial Intelligence (AI), with its vast areas of application scenarios, allows for these challenges and more to be tackled in the spacecraft design. Particularly, the flexibility of Artificial Neural Networks as Machine Learning technology provides many possibilities. For example, Artificial Neural Networks can be used for object detection and classification tasks. Unfortunately, the execution of current Machine Learning algorithms consumes a large amount of power and memory resources. Additionally, the qualification of such algorithms remains challenging, which limits their possible applications in space systems. Thus, an increase in efficiency in all aspects is required to further enable these technologies for space applications. The optimisation of the algorithm for System on Chip (SoC) platforms allows it to benefit from the best of a generic processor and hardware acceleration. This increased complexity of the processing system shall allow broader and more flexible applications of these technologies with a minimum increase of power consumption. As Commercial off-the-shelf embedded systems are commonly used in NewSpace applications and such SoC are not yet available in a qualified manner, the deployment of Machine Learning algorithms on such devices has been evaluated. For deployment of machine learning on such devices, a ConvolutionalNeural Network model was optimised on a workstation. Then, the neural network is deployed with Xilinx’s Vitis AI onto a SoC which includes a powerful generic processor as well as the hardware programming capabilities of an Field ProgrammableGate Array (FPGA). This result was evaluated based on relevant performance and efficiency parameters and a summary is given in this thesis. Additionally, a tool utilising a different approach was developed. With a high-level synthesis tool the hardware description language of an accelerated linear algebra optimised network is created and directly deployed into FPGA logic. The implementation of this tool was started, and the proof of concept is presented. Furthermore, existing challenges with the auto-generated code are outlined and future steps to automate and improve the entire workflow are presented. As both workflows are very different and thus aim for different usage scenarios, both workflows are outlined and the benefits and disadvantages of both are outlined.

Preservation and protection of the head segment is of upmost importance due to the criticality of the functions entailed in this section of the body by the brain and the nervous system. Numerous events in daily life situations such as transportation and sports pose threats of injuries that may end or change a person’s life. In the European Union, statistics report that almost 4.2 million of road users are injured non-fatally, out of which 18% is represented by motorcyclist and 40% by cyclists, being head injuries 34% for bicyclists, and 24% for two-wheeled motor vehicles. Not only vehicles, are a source of injuries for the human head according to the injury report, 6,1 million people are admitted in hospitals for sports related injuries, where sports such as hockey, swimming, cycling presented head injuries up to 28%, 25% and 16% respectively (European Association for Injury Prevention and Safety Promotion, 2013).  According to records the vast majority of head crashes result in an oblique impact (Thibault & Gennarelli, 1985). These types of impacts are characterized for involving a rotation of the head segment which is correlated with serious head injuries. Even though there is plenty of evidence suggesting the involvement of rotational forces current helmet development standards and regulations fail to recognize their importance and account only for translational impact tests. This thesis contains an evaluation for a different developed method for testing oblique impacts. In consequence a new test rig was constructed with basis on a guided free fall of a helmeted dummy head striking an oblique (angled) anvil which will induce rotation. The results obtained are intended to be subjected to a comparison with another oblique test rig that performs experiments utilizing a movable sliding plate which when impacted induces the rotation of a dropped helmeted dummy head. The outcome will solidify the presence of rotational forces at head-anvil impact and offer an alternative testing method. After setting up the new test rig; experiments were conducted utilizing bicycle helmets varying the velocities before impact from 5m/s to 6m/s crashing an angled anvil of 45°. Results showed higher peak resultant values for rotational accelerations and rotational velocities in the new test rig compared to the movable plate impact test, indicating that depending on the impact situation the “Normal Force” has a direct effect on the rotational components. On the other hand a performed finite element analysis predicted that the best correlation between both methods is when the new angled anvil impact test is submitted to crashes with a velocity before impact of 6 m/s at 45° and the movable sliding impact test to a resultant velocity vector of 7,6m/s with an angle of 30° . In conclusion the new test method is meant to provide a comparison between two different test rigs that will undoubtedly have a part in the analysis for helmet and head safety improvements.

Syftet med studien var att undersöka hur lärare kan identifiera och utmana elever som är särskilt begåvade i matematik. Genom kvalitativ metod i form av fem intervjuer och en enkätundersökning som har besvarats av 20 verksamma lärare har jag fått in data om hur lärare identifierar och utmanar särskilt begåvade elever. Studien visar att flertalet lärare tycker det är svårt att utmana dessa elever med särskild begåvning då de saknar kunspa inom det området, samt att det inte finns några specifika metoder på de flesta arbetsplatserna för identifiering av den här typen av begåvning. Det vanligaste sättet lärarna i studien använder är att utmana eleverna genom acceleration i form av att låta de arbeta vidare i matteboken eller med problemlösning. Eleverna arbetar antigen kvar i matteboken som tillhör årskursen eller så får de arbeta i en mattebok för en annan årskurs.

To deal with an increasing demand in transportation, trains are made longer and faster. Higher speeds imply higher impacts on bridges. Therefore, structures have to be designed to resist these new constraints. The Eurocode (2002) introduced additional checks for the design of high-speed railway bridges. Among them, the maximum vertical deck acceleration criterion often determines alone the design of the structure. Tests on shake table brought to the conclusion that vertical bridge deck acceleration should never exceed 3.5 m/s2 for ballasted tracks. This master thesis investigates the optimization of cross section parameters of single-track simply supported and double-span bridges based on the limit of the maximum vertical deck acceleration criterion. The first natural frequency is considered as a proof of the feasibility of the structure. The optimization is carried out through MATLAB for both types of bridges. The deck acceleration of simply supported bridges is analytically calculated using the Train Signature (ERRI D214 1999) in MATLAB. The dynamic calculations of double-span bridges are implemented through the finite element software ABAQUS. The implemented programs have been verified by comparison to values of simple cases found in the literature. Structures are tested under the influence of the ten HSLM-A trains of the Eurocode running at speeds between 150 km/h and 350 km/h. Optimization algorithms are presented and compared in this study but their applicability in such context is questioned. Indeed, as the problem contains several suitable minima, the algorithms, which end in one solution, are not adapted. To overtake this difficulty, a scanning of the interesting zone is advised. However, the latter is very time consuming, even more if the finite element analysis is used. Suggestions to decrease analysis time are presented in this report. Single span composite bridges with a span longer than 20 m appeared to be impossible to optimize within the objectives defined in this work (i.e. considering limits of deck acceleration and first natural frequency), which draws doubts about their suitability for high-speed railways. Nevertheless, simply supported bridges made of concrete seem more adapted for high-speed railways and their optimized parameters are presented in this work. Optimized parameters for double-span concrete bridges are also presented.

<div>Since the discovery of chronic traumatic encephalopathy (CTE) in retired professional football players, the long-term neurological safety of these athletes has been called into</div><div>question. Studies revealed that those who play football are at higher risk for developing neurological deficits such as Parkinson’s and Alzheimer’s diseases. It has also been observed that participation in contact sports can result in neurological changes detectable with magnetic resonance imaging (MRI) that do not present with any easily observable clinical symptoms. Changes in brain chemistry, structure, and blood flow have been observed over the course of a season of contact sports. These changes are thought to be caused by the repetitive head acceleration events (HAEs) sustained by contact sport athletes, with the magnitude and number of HAEs correlating with some changes. This dissertation aims to characterize and reduce the HAEs sustained by contact sport athletes with a specific focus on football players.</div><div><br></div><div>Studies of middle school and high school football players revealed that there are likely offsetting effects that result in similar HAEs between the two groups. As one plays at higher levels of play with typically bigger, stronger, faster athletes that should result in higher magnitude HAEs, there is likely an improvement in tackling technique used at higher levels that make it so there are similar HAEs among different levels of play. Examining middle school football and high school football and girls’ soccer athletes indicate that players that play on two teams (i.e. a player that plays both Varsity and Junior Varsity) may be at an increased risk for neurological changes due to over-exposure. It was revealed when studying post-collegiate football the up stance offensive linemen may help reduce the frequency of HAEs compared to the down stance. However, the skill of the offensive lineman needs to be accounted for to determine if it is beneficial for players to start in this stance.</div><div><br></div><div>Repetitive HAEs (rHAEs), whether due to body or direct head impacts arising from participation in contact sports, are correlated with alterations in white matter health. Fractional anisotropy (FA) and mean diffusivity (MD), two metrics used to assess white matter structural integrity, typically change in opposite directions (one increases while the other decreases) after brain injury. This study investigated the manner in which participation in American football affects the percentage of white matter exhibiting the four possible change combinations: increased FA, increased MD; decreased FA, increased MD; increased FA, decreased MD; decreased FA, decreased MD. Diffusion tensor imaging data of 61 high school football and 15 non-contact athletes were analyzed. After a season of participation, football athletes exhibited a significantly greater percentage of deviant voxels in each of the four categories than were observed from test-retest of non-contact athletes. Even prior to a season of participation, football athletes exhibited significantly more voxels in each of the categories, relative to controls. Of particular concern is that voxels exhibiting jointly decreased FA and MD—a change typically associated with cell death—were observed at a significantly higher rate within football athletes than non-contact athletes. This finding suggests that rHAEs may increase the incidence of cell death, and argues for the greater adoption of methods aimed at reducing mechanical loading on the brain from rHAEs, both through reduction of the number of HAEs, and development of better protective equipment.</div><div><br></div><div>Rugby is a sport that is very similar to football in terms of physicality and overall objective, but there are marked differences in protective equipment and style of play. These differences in protective equipment result in different tackling rules and styles between the two sports that may influence the effect repetitive HAEs can have on neurological health. Therefore, the HAEs experienced over the course of the season by New Zealand collegiate (ages 16+) rugby athletes were characterized. The number of HAEs were compared by position (forward vs. backs) and the peak translation acceleration (PTA) of the HAE was analyzed by position, possession (offense vs. defense), and cause of HAE (tackle vs. ruck). Forwards (although not significantly) tended to sustain more HAEs than backs, but there were no differences in the magnitude of the HAEs by any of the types of comparisons. However, when considering possession and type of HAE simultaneously, it was found that HAEs in a defensive ruck are more severe than those sustained in an offensive ruck. This could be a potential place to work on player technique to reduce the PTA during these situations.</div><div><br></div><div>There are numerous studies that have utilized accelerometers to quantify head motion during a contact event, but a current gap in the field is quantification of the impact force. In order to capture high force events, an instrumented helmet using strain was built to capture this data. Strain gauges were adhered to the inside of a Riddell Speedflex helmet shell and then mounted onto a Hybrid III Headform for testing. The helmet was hit at four different locations (front, right, back, and left) and at different impulse ranges (2-5 Ns, 5-8 Ns, 8-11 Ns, and 11+ Ns). The strain gauges were able to classify the location of the hit with about 95% accuracy and were correlated the impact peak force and impulse. This suggests that it is possible to build an instrumented helmet to be worn by a football player during collision events to capture real impact force and location data.</div>

Enligt Skollagen (SFS 2010:800) har alla elever rätt till en likvärdig och meningsfull utbildning. Det innebär att varje elev, oavsett fallenhet eller svårighet i undervisning har rätt till vägledning och stimulans för att nå längre i sin kunskapsutveckling. Elever som anses starka ska få individanpassad undervisning som utmanar eleverna utifrån deras kunskaper och förutsättningar. Men finns det risker med att denna rättighet, som borde vara en självklarhet, inte uppfylls av skolors verksamhet? Denna kvalitativa intervjustudie syftar till att undersöka och ge exempel på hur rektorer och lärare stödjer starka elever i matematik utifrån skolans uppdrag och ansvar. Intervjustudien grundar sig i det sociokulturella perspektivet och utgår från frågeställningarna: Hur planerar och genomför skolor arbetet med de starka eleverna i matematik? och Hur kan lärare i F-3 arbeta för att ge starka elever i matematik ledning och stimulans att nå längre i sin kunskapsutveckling?   udien visar att skolor saknar strategier på hur lärare kan hjälpa starka elever på bästa sätt, vilket kan medföra att denna elevgrupp blir sittandes i väntan på resterande elever. Uppdraget och ansvaret att anpassa undervisningen ligger idag hos läraren, ett ansvar som borde ligga på verksamheten eller hos regeringen. Studien lyfter dock ett arbetssätt för att individanpassa  undervisning för starka elever i skolans ämnen. Detta arbetssätt innefattar en accelererande och berikande undervisning där eleven även får coachning och stöd genom hela sin skolgång för att få möjlighet att utvecklas så långt som möjligt. / Abstract According to Skollagen (SFS 2010:800), every student has the right to an equal and meaningful education. It means that regardless if the students have easy to learn or have learning difficulties, they have the right of guidance and stimulation to grow in their knowledge development. Students that are considered as strong learners must receive individualized education that challenges the students based on their individual needs. The question is if this right, that should be obvious, really is fulfilled in the schools´ education? This qualitative interview study aims to investigate and give examples of how principals and teachers support strong students in mathematics based on the school's assignment and responsibilities. The interview study is based on Vygotskijs’ socio-cultural perspective and assume the questions: How do schools plan and implement the work with the strong students in mathematics? and How can teachers in F-3 work to give strong students in mathematics guidance and stimulus to reach further in their knowledge development? The study indicates that schools lack strategies on how teachers can help strong students in the optimal way, which can implicate that this group of students is held back because of the remaining students. The assignment and responsibility to adapt the teaching today lies with the teacher, a responsibility that should lie with the organization or with the government. However, the study accents a way of working to individualize teaching for strong students in school courses. This approach includes an accelerating and enriching teaching where the students also receives coaching and support through the years in primary school to have the opportunity to develop in knowledge as far as possible.