Examensarbetet har handlat om hur man med produktdesign kan öka synligheten hostjejer i åldrarna 18-25 år som rör sig i urbana, trafikerade miljöer under de mörkadelarna av dygnet.Genom intervjuer, frågeformulär och litteraturstudie urskönjdes att målgruppenvar väl medveten om nyttan med reflexanvändning men att detta trots allt inte var ettstarkt nog motiv till att använda reflexer då existerande produkter ansågs löjliga,opraktiska och fula.Vad som huvudsakligen har bearbetats är mjuka värden såsom status och estetiksamt yttre krav på ett optimerat reflexbärande.Resultatet är en väska som med sin multifunktionalitet och sobra estetik medgersynlighet för brukaren. Det är en reflexprodukt som målgruppen kan identifiera sig medoch bära vid många tillfällen. / The subject of this thesis regards how product design can be used to increase visibility indarkness. The target group is girls aged 18-25 when in an urban, trafficked contextduring the darker hours of the day.Through interviews, surveys, and a literature study it was discovered that thetarget group is well aware of the benefits of using reflectors, however this is not a strongenough motif for using them since products already on the market are considered silly,impractical, and ugly.The main focus has been to consider soft values such as status and aesthetics aswell as requirements regarding an optimized usage of reflectors.This has resulted in the design of a modest, yet stylish multifunctional bag, withthe aim to make the user visible. It is a reflective product that the target group canidentify themselves with and carry at all times.

In recent experiments involving acceleration stimuli, researchers instructed subjects to focus on a visual target while measuring the vestibulo-ocular reflex (VOR) in one eye. These experiments showed conclusively that the VOR is influenced by target distance. We, on the other hand, were interested in investigating the VOR of subjects accelerated in complete darkness. Specifically, we wished to determine the subject's vergence point, which cannot be accomplished using data obtained from only one eye. Hence, a binocular eye-tracking system that works in the dark was required. In the experiment described in this thesis, the subject was rotated in the dark on NAMRL's Coriolis Acceleration Platform. The position of each pupil center was tracked and recorded by two helmet-mounted infrared cameras connected to a computer-controlled data acquisition system. The position data were used to calculate the angles through which the eyes rotated, and then trigonometric principles were applied to construct the line of sight for each eye for any moment in time; the intersection of these two lines is the vergence point. With the NAMRL binocular eye-tracking system, an accelerating subject's vergence point can accurately be determined if it is less than 1. 5 meters away. The vergence data obtained from this experiment suggest that vergence distance does not exclusively drive the VOR in the dark. / Master of Science

The stability of the spine can be estimated from kinematic variability and nonlinear analyses of seated balance tasks. However, processing methods require sufficient signal duration and test-retest experiments require that the assessment must be reliable. Our goal was to characterize the reliability and establish the trial duration for spine stability assessment. Stationarity, kinematic variability and nonlinear dynamic stability were quantified from kinetic and kinematic data collected during balance performance. Stationarity results showed that a minimum 30 seconds test duration is necessary. Intra-session reliability was excellent, however inter-session reliability needed more test trials to achieve excellent reliability. Few studies have investigated the spinal stability during pushing and pulling exertions. Past studies suggest that the spine can be stabilized by paraspinal muscle stiffness as well as reflexes. We hypothesized that the stability of the spine decreases with exertion force and decreases during pushing more than during pulling exertion. Kinematic variability and nonlinear dynamic stability measurements were quantified from the balance performance during isometric pushing and pulling tasks. Results demonstrated that spinal stability decreased with exertion force and decreased a greater amount during pushing task than during pulling task. Stiffness alone may be insufficient to stabilize the trunk. Results may be able to be explained by slower reflex delay. The results suggested that pushing and pulling exertions have a potential risk of low-back disorders. / Master of Science

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2008. / A solution is sought for the measurement of human deep tendon reflexes as part of a comprehensive patient condition monitoring system for use in a telemedicine context. This study focused on the development, testing and performance evaluation of a prototype compact patellar tendon reflex measurement system that is able to provide a quantitative reflex evaluation for use by medical practitioners and in a telemedicine environment. A prototype system was developed that makes use of Xsens MTx orientation sensors, force-sensing resistors and an electromyogram (EMG) to measure the reflex response. Suitable parameters identified for analysis included the change in pitch, angular velocity and acceleration of the lower leg, the EMG response, the tendon impact, and various latencies associated with these measurements. Other information considered included the age, mass, and physical dimensions of the test subject. Clinical testing was performed to collect data to evaluate the system performance. Subjective reflex evaluations were conducted by three doctors according to a standard reflex grading scale using video recordings of the tests. Self-organizing maps and multi-layer feed-forward (MLFF) artificial neural networks (ANNs) were used to analyze the collected data with the aim of pattern identification, data classification and reflex grading prediction. It was found that the MLFF network delivered the correct reflex grading with an accuracy of 85%, which was of the same order as the rate of differences between the subjective reflex evaluations performed by the doctors (80%). Furthermore, analysis of the data suggested that certain parameters were not necessary for the autonomous evaluation, such as EMG data and the tendon impact. The use of ANNs to analyze a reflex measurement as proposed by this study offers an accurate, repeatable and concise representation of the reflex that is familiar to doctors and suitable for use in a general clinical setting or for telemedicine purposes.

In order for stroke subjects to gain functional recovery of their hemiparetic limbs, facilitation techniques such as the repetitive facilitation exercise, or RFE, have been developed. Currently, there is a lack of understanding of the neural mechanisms associated with these types of facilitation techniques. To better understand the neural mechanisms associated with the RFE a functional magnetic resonance imaging (fMRI) study should be conducted. This thesis presents experimental results testing the feasibility of implementing an fMRI-compatible actuator to facilitate a myotatic reflex in synchronization with the subject’s intention to move their hemiparetic limb. Preliminary data from a healthy individual demonstrated the feasibility of overlapping the long latency component of the afferent myotatic reflex, created by electrical stimulation, with descending nerve impulses, created using transcranial magnetic stimulation, in a time window of 15ms. In addition, a pneumatic actuation time delay due to long transmission line was evaluated. The pneumatic actuator met the timing precision requirement for the rehabilitation device for varying transmission line lengths. Therefore a pneumatic actuation system was chosen for the rehabilitation device. This thesis will also presents on the design of an fMRI-compatible pneumatic actuator device to excite a stretch reflex response. Initial, experimental results with the device demonstrated that the designed pneumatic device can control the timing of the muscle response with a fixed signal within the required 15ms window required for cortical facilitation, which was found in the previous feasibility study. However, the device was unable to create a long latency reflex observable at the muscle. Finally, this thesis presents on the capability of the device in creating subthreshold long latency response with precision to overlap with a subthreshold descending nerve impulse, created using transcranial magnetic stimulation. The overlap of the two responses was evaluated by comparing the amplitude of the muscle response with and without the stretch reflex, created by the fMRI-compatible pneumatic actuator device. Varying time delays were analyzed.

This diploma work examines a product from the field of print media - front pages of magazine Reflex. Method of mythological analysis is used, which has been in qualitative research of media content applied for half of a century and is considered to be one of the traditional methods used by media studies. Unlike other dissertations in this thematic area this work does not only analyze visual or lexical contents of cover pages, but also focuses on participation of those contents in the development of myth. The work begins with introduction of key theoretical background and resulting terms used in following analyzes describing effects of myths in individual covers. Then the summary brings the interpretation and explanation of described phenomena. The work focuses to decipher myths contained in the first message which the Reflex magazine week after week addresses to his readers -the title page of individual issues. It analyses how the magazine constructs a system of myths, by which ideology can impact on its readers. Aim of this dissertation is not only to describe the process by which the myths capture a variety of signs and fill them with their own meanings, but also a dialectical relationship between myths and stereotypes or ideologies which stand in their background.

Tem sido sugerido que combinar o treinamento de força (TF) com o treinamento com vibração (TV) pode ser mais vantajoso do que realizar o TF isolado. OBJETIVOS: Foi objetivo deste estudo avaliar os efeitos da combinação do TF com o TV (TF+V) sobre o desenvolvimento de hipertrofia e os desempenhos da força máxima dinâmica de membros inferiores (FMD) e do salto vertical (SV). Investigou-se também se os benefícios proporcionados pelo treinamento são acompanhados por alterações agudas e crônicas na excitabilidade das vias reflexas. METÓDOS: Foram realizados dois experimentos. No primeiro, foram avaliados os efeitos de uma sessão de treinamento sobre o desempenho do SV e excitabilidade das vias reflexas. Doze sujeitos do sexo masculino foram submetidos a quatro condições experimentais. Na condição TF, realizaram cinco séries de 10 repetições do exercício agachamento, com 90% da massa corporal. Nas condições TF+V30 e TF+V50, o TF foi realizado sobre a plataforma vibratória nas freqüências de 30 Hz (2-4 mm) e 50 Hz (4-6 mm), respectivamente. Na condição controle (C), os sujeitos permaneceram em repouso. Antes e depois de todas as condições experimentais, foram mensurados o desempenho do SV, e os reflexos de Hoffmann (H com amplitude de 20% da onda M máxima, H20%) e tendíneo máximo (Tmáx), no músculo sóleo. No segundo experimento, 29 sujeitos do sexo masculino foram divididos aleatoriamente nos grupos TF, TF+V30 e TF+V50. Os três grupos realizaram entre 3-5 séries de 6-12 RM do exercício agachamento, duas vezes por semana, durante dez semanas. Os grupos TF+V30 e TF+V50 fizeram o agachamento sobre a plataforma vibratória nas freqüências de 30 Hz (amplitude de 2-4 mm) e 50 Hz (amplitude de 4-6 mm), respectivamente. Antes e depois do período de treinamento, foram avaliados a área de secção transversa do quadríceps femoral (ASTQ), os desempenhos da FMD e do SV, os reflexos H e T máximos (Hmáx e Tmáx) e a onda M máxima (Mmáx), no músculo sóleo. RESULTADOS: No primeiro experimento, não foram verificadas alterações significantes na amplitude de H20% em nenhuma das condições (p>0,05). Houve diminuições significantes na amplitude das ondas Tmáx, nas condições TF (-7,4%) e TF+V50 (-11,1%), no primeiro minuto, em comparação ao período antes da intervenção (p<0,001). Foram verificadas diminuições significantes na altura do SV após a realização de todas as condições (C= -11,8%, TF= -6,6%, TF+V30= -7,7% e TF+V50= -7,4%) (p<0, 001). Não houve diferenças significantes entre grupos em nenhuma das variáveis (p>0,05). No segundo experimento, após as dez semanas de treinamento, foram verificados aumentos significantes na ASTQ (TF= 9,8%, TF+V30= 11,7%, TF+V50= 12,9%); na FMD (TF= 16,9%, TF+V30= 15,2%, TF+V50= 16,6%) e na altura do SV (TF= 6,0%, TF+V30= 7,2%, TF+V50= 6,0%) para os três grupos (p<0,05). Não houve diferença significante entre grupos em nenhuma das três variáveis. O período de treinamento não causou alterações significantes nas razões Hmáx/Mmáx (TF = +28%, TF+V30 = -16,3%, TF+V50 = -14%) e Tmáx/Mmáx (TF = -30,3%, TF+V30 = -38,2%, TF+V50 = -28,1%) (p>0,05). Contudo, foi verificado efeito principal de tempo significante para a razão Tmáx/Mmáx (-48,9%) (p<0,05). CONCLUSÕES: A realização de uma sessão de treinamento de força causa uma breve redução da atividade dos fusos musculares. Essa redução não é ampliada quando o TF é combinado com vibração. Realizar um período de TF sobre a plataforma de vibração não proporciona qualquer aumento adicional na ASTQ ou nos desempenhos da FMD e do SV, em relação ao que pode ser conseguido através do TF / It has been suggested that the combination of strength and vibration training may be advantageous when compared with strength training alone. OBJECTIVES: The aim of this study was to assess the effects of combined strength training and vibration (ST+V) on lower limb hypertrophy and on maximal dynamic strength (MDS) and vertical jump (VJ) performances. In addition, we investigate if the training-induced adaptations were in agreement to acute and chronic changes on spinal reflex excitability. METHODS: Two experiments were performed. In the first experiment, the effects of a single training session on VJ performance and spinal reflexes excitability were assessed. Twelve young male undertook four experimental conditions. On ST condition, subjects performed five sets with 10 repetitions on squat exercise with load of 90% body mass. On both ST+V30 and ST+V50 conditions, subjects performed the ST on a vibration platform at 30 Hz (2-4 mm) and 50 Hz (4-6 mm), respectively. In C condition, subjects were only assessed. Vertical jumping performance and Hoffman (at 20% of maximal M wave, H20%) and maximal tendon soleus reflexes (Tmáx) were measured before and after all experimental conditions. In the second experiment, twenty nine young male were randomized into three groups. All groups performed 3-5 sets with 6-12 RM on squat exercise, twice a week, for ten weeks. The ST+V30 and ST+V50 groups performed the squat exercise on the vibration platform at 30 Hz (2-4 mm) and 50 Hz (4-6 mm), respectively. Quadriceps cross sectional area (QCSA), MDS and VJ performances, maximal soleus H- and T- reflexes and maximal M wave (Mmáx) were assessed before and after the 10-week training period. RESULTS: in the first experiment, no significant changes were found in H20% amplitude in any experimental condition (p>0,05). Significant decrease on Tmáx amplitude was found after ST+V30 (-7.4%) and ST+V50 (-11.1%) conditions, after the first minute, compared to before intervention assessment. VJ decreased in all experimental conditions (C= -11.8%, ST= -6.6%, ST+V30= -7.7% and ST+V50= -7.4%) (p<0.001). There were no significant changes between groups in any variable measured (p>0.05). In the second experiment, significant increases were found in QCSA (ST= 9.8%, ST+V30= 11.7%, ST+V50= 12.9%); MDS (ST= 16.9%, ST+V30= 15.2%, ST+V50= 16.6%) and VJ height (ST= 6.0%, ST+V30= 7.2%, ST+V50= 6.0%) in all groups (p<0.05). There were no significant changes between groups in any variable measured (p>0.05). The training period did not induce significant changes in Hmáx/ Mmáx (ST = +28%, ST+V30 = -16,3%, ST+V50 = -14%) and Tmáx/ Mmáx ratios (ST = -30,3%, ST+V30 = -38,2%, ST+V50 = -28,1%) (p>0.05). However it was found a significant time effect for Tmáx/ Mmáx ratio (-48.9%) (p<0,05).CONCLUSION: A single strength training session induces a brief impairment on muscle spindle activity. This impairment is not greater if ST is combined with vibration. Performing ST on a vibration platform did not additionally increase QCSA, MDS and VJ performance compared with ST alone

Professional research project (Au.D.)--University of South Florida, 2002. / Title from PDF of title page. / Document formatted into pages; contains 24 pages. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Patients with non-compensated vestibular dysfunction frequently complain of the ability to maintain dynamic visual acuity during activities which require the movement of the head. When this occurs the patient is experiencing oscillopsia, which is the symptom resulting from a non-functional vestibulo-ocular reflex (VOR). To measure the presence of oscillopsia, tests of dynamic visual acuity (DVA) may be used.A recent test of DVA has been reported which is administered while patients are walking on a treadmill. Although this test has been shown to be useful in evaluating DVA in patients, there are several disadvantages to treadmill use. These include physical space, cost and accessibility. Additionally, walking at the required treadmill speed to produce sufficient head movement may pose difficulties and be medically contraindicated for patients with certain health risks. The purpose of this study was to evaluate a different method to measure DVA in patients which would not require the use of the treadmill, but instead utilize a volitional head movement to reveal oscillopsia. In this study, patients performed the DVA test in two conditions: (1) walking on a treadmill, and (2) seated on a chair volitionally moving the head.In this study, DVA was tested in both conditions with 15 adults with normal vestibular function, and 16 adults with vestibular impairment. Results revealed that both methods, treadmill walking and volitional head movement, appeared equivalent for measuring DVA in normal subjects and vestibular impaired subjects. The lack of finding a significant main effect of method, and interactions that include method, supports the equivalence of volitional head movement to a treadmill approach for the measurement of DVA. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

Muscle performance is partially a consequence of its recent contractile history. Postactivation potentiation (PAP) can occur after muscle contractions and leads to enhanced neuromuscular performance. The purpose of this dissertation was to explain the relationship between muscle factors (twitch potentiation, TP) and neural factors (reflex potentiation, RP) contributing to overall PAP following a non-fatiguing volitional muscle contraction. The tibial nerves of fifteen resistance trained volunteers (eleven men, four women) were stimulated intermittently at supramaximal (Mmax) and submaximal (Hmax) intensities for 20 minutes on separate days under three conditions: rest (Control); after a after a 10 second maximum voluntary isometric contraction (MVIC) of the plantarflexors; and after a low frequency fatigue protocol prior to the MVIC. Plantarflexion isometric torque and rate of force development (RFD), and soleus and gastrocnemius EMG Hmax/Mmax ratios, were analyzed. Both experimental conditions resulted in TP at 10 seconds post-MVIC compared to the control condition. The two experimental conditions were not different for any measure. Torque and RFD at Hmax (overall PAP) were highest at 3 and 4.5 minutes post MVIC, respectively, but were not significantly different from the control condition. EMG values generally were insignificantly increased in the experimental conditions versus the control condition. Mmax torque and RFD significantly contributed to Hmax torque and RFD at 20 seconds, Hmax peak, and 20 minute post-MVIC time points. The soleus significantly contributed to Hmax torque at 20 seconds and 20 minutes post-MVIC, and Hmax RFD at 20 seconds, 4.5 minutes, and 20 minutes post-MVIC. The results of this study suggest that both muscle and neural factors play a significant role in overall PAP, and that neural factors may play a more meaningful role in RFD potentiation than torque potentiation.

The focus of this thesis was to study an action that humans perform regularly, namely, to hold a morsel between the teeth and split it into smaller pieces. Three different issues related to this biting behavior were addressed:  (1) the effect of redu­c­ed perio­dontal tissues on food holding and splitting behavior; (2) the behavioral conse­quences of performing different bite tasks with different functional requirements, i.e., to split a peanut half resting on a piece of chocolate or to split both the peanut and the chocolate; and (3) the reflex modulations resul­ting from such a change in the intended bite action. The main conclusions from the experi­mental studies were the following: First, perio­dontitis, an inflam­matory disease that destroys the peri­o­dontal ligaments and the embedded perio­dontal mechanoreceptors, causes significant impairments in the masticatory abili­ty: the manipulative bite forces when holding a morsel are elevated compared to a matched control population and the bite force development prior to food split is altered. These changes are likely due to a combination of reduced sensory informa­tion from the damaged ligaments and to changes in the bite stra­tegy secon­d­ary to the unstable oral situation. Second, people exploit the anatomy of jaw-closing muscles to regulate the amount of bite force that dissipates following a sudden unloading of the jaw. Such control is necessary because without mechanisms that quickly halt jaw-closing movements after sudden unloading, the impact forces when the teeth collide could otherwise damage both the teeth and related soft tissues. Splitting a piece of chocolate, for instance, regularly requires &gt;100N of bite force and the jaws collide within 5 ms of a split. On the other hand, when biting through heterogeneous food, the bite force needs to be kept high until the whole morsel is split. The required regulation is achieved by differen­tial­ly engaging parts of the masseter muscles along the anteroposterior axis of the jaw to exploit differences between muscle portions in their bite force generating capa­ci­ty and muscle shortening velocity. Finally, the reflex evoked by suddenly unloading the jaw—apparent only after the initial bite force dissipation—is modulated according to the bite intention. That is, when the intention is to bite through food items with multiple layers, the reflex response in the jaw opening muscles following a split is small, thus minimizing the bite force reduction. In contrast, when the intention is to rapidly decrease the bite force once a split has occurred, the reflex response is high. This pattern of reflex modulation is functionally beneficial when biting through heterogeneous food in a smooth manner. The presented studies show the significance of integrating cogni­tive, physiological and anatomical aspects when attempting to understand human masticatory control.