4,882 research outputs found
Beam scanning by liquid-crystal biasing in a modified SIW structure
A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium
Ăvaluation de lâĂ©quilibre postural et du patron de marche chez les individus adultes avec et sans fasciopathie plantaire
La fasciopathie plantaire est lâune des atteintes musculosquelettiques la plus commune aux pieds. Elle a une prĂ©valence de 7% dans la population autant chez les hommes que chez les femmes et touche principalement la tranche dâĂąge se situant entre 45 et 64 ans. Le fascia plantaire a comme rĂŽle le support des diffĂ©rentes arches plantaires ainsi que le transfert des forces durant les diffĂ©rentes phases de la marche. Une blessure Ă celui-ci peut avoir un impact sur la fonctionnalitĂ© de lâindividu. Ce mĂ©moire a pour but dâĂ©valuer si la fasciopathie plantaire a un impact sur lâĂ©quilibre postural ainsi que le patron de marche dans diffĂ©rentes conditions. 30 participants (15 avec fasciopathie plantaire) ont eu Ă effectuer 5 tĂąches dâĂ©quilibre diffĂ©rentes sur une plateforme de force sur laquelle les dĂ©placements du centre de pression Ă©taient analysĂ©s pour Ă©valuer le contrĂŽle postural. Les participants devaient aussi effectuer un test de marche sur le systĂšme GaitRite en marchant selon 3 vitesses diffĂ©rentes pour lâĂ©valuation de diffĂ©rentes donnĂ©es spatio-temporelles Ă la marche. De plus, diffĂ©rentes mesures du pied Ă©taient effectuĂ©es pour Ă©valuer la mobilitĂ© ainsi que la douleur. Aucune diffĂ©rence statistiquement significative nâa Ă©tĂ© trouvĂ©e entre les deux groupes pour ce qui est des mesures cliniques du pied, exceptĂ© pour la douleur Ă la palpation qui Ă©tait significativement plus Ă©levĂ©e chez le groupe avec fasciopathie plantaire. Pour lâĂ©quilibre postural, une diffĂ©rence significative a Ă©tĂ© observĂ©e entre les deux groupes pour la variable aire de centre de pression (p < 0,01; d = 0,08) et vitesse dâoscillation dans la direction antĂ©ro-postĂ©rieure (p = 0,022; d = 0,04), suggĂ©rant une diminution du contrĂŽle postural parmi les participants avec fasciopathie plantaire. Pour la marche, il a Ă©tĂ© dĂ©montrĂ© chez le groupe pathologique une diminution de la vitesse (p < 0,01; d = 0,12), la longueur des pas (p < 0,01; d = 0,16) et de la largeur des pas (p < 0,01; d = 0,18) par rapport au groupe contrĂŽle durant les trois vitesses de marche effectuĂ©es. En conclusion, les individus atteints de fasciopathie plantaire prĂ©sentaient une diminution du contrĂŽle postural, surtout lors dâune tĂąche dâĂ©quilibre plus difficile (semi-tandem et unipodal) ainsi que des changements dans leur patron de marche comparativement Ă un groupe contrĂŽle. Ces rĂ©sultats ont des implications pour la prise en charge clinique associĂ©e aux limitations physiques comme lâĂ©quilibre et la marche des individus souffrant de fasciopathie plantaire lors dâun programme de rĂ©adaptation
Non-inertial Undulatory Locomotion Across Scales
Locomotion is crucial to behaviors such as predator avoidance, foraging, and mating. In particular, undulatory locomotion is one of the most common forms of locomotion. From microscopic flagellates to swimming fish and slithering snakes, this form of locomotion is a remarkably robust self-propulsion strategy that allows a diversity of organisms to navigate myriad environments. While often thought of as exclusive to limbless organisms, a variety of locomotors possessing few to many appendages rely on waves of undulation for locomotion. In inertial regimes, organisms can leverage the forces generated by their body and the surrounding medium's inertia to enhance their locomotion (e.g., coast or glide). On the other hand, in non-inertial regimes self-propulsion is dominated by damping (viscous or frictional), and thus the ability for organisms to generate motion is dependent on the sequence of internal shape changes. In this thesis, we study a variety of undulating systems that locomote in highly damped regimes. We perform studies on systems ranging from zero to many appendages. Specifically, we focus on four distinct undulatory systems: 1) C. elegans, 2) quadriflagellate algae (bearing four flagella), 3) centipedes on terrestrial environments, and 4) centipedes on fluid environments. For each of these systems, we study how the coordination of their many degrees of freedom leads to specific locomotive behaviors. Further, we propose hypotheses for the observed behaviors in the context of each of these system's ecology.Ph.D
Brain Computations and Connectivity [2nd edition]
This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read on the Oxford Academic platform and offered as a free PDF download from OUP and selected open access locations.
Brain Computations and Connectivity is about how the brain works. In order to understand this, it is essential to know what is computed by different brain systems; and how the computations are performed.
The aim of this book is to elucidate what is computed in different brain systems; and to describe current biologically plausible computational approaches and models of how each of these brain systems computes.
Understanding the brain in this way has enormous potential for understanding ourselves better in health and in disease. Potential applications of this understanding are to the treatment of the brain in disease; and to artificial intelligence which will benefit from knowledge of how the brain performs many of its extraordinarily impressive functions.
This book is pioneering in taking this approach to brain function: to consider what is computed by many of our brain systems; and how it is computed, and updates by much new evidence including the connectivity of the human brain the earlier book: Rolls (2021) Brain Computations: What and How, Oxford University Press.
Brain Computations and Connectivity will be of interest to all scientists interested in brain function and how the brain works, whether they are from neuroscience, or from medical sciences including neurology and psychiatry, or from the area of computational science including machine learning and artificial intelligence, or from areas such as theoretical physics
Worshipping at the Shrine of Wagner: Fandom, Media and Richard Wagner
Nineteenth-century opera composer Richard Wagner has long inspired passionate responses, with contemporary commentators often noting the cult-like reverence with which lovers approached his operas. In the years since, however, interest in Wagnerâs art has not disappeared. In this dissertation, I explore the contours of modern Wagnerism using as my primary case study the Toronto Wagner Society, asking how members incorporate opera into their lives and what Wagner means to them. To do this, I employ a multimethodology of ethnography, an examination of Wagnerâs art and rhetoric, and a consideration of the materiality of opera. These findings are analyzed through a dual lens of fan studies and cultural techniques, with which this dissertation makes two principal moves: first, to highlight how fandom of high culture is different in nature, not in kind to fandom of popular culture; second, to propose a networked model of fandom, one which conceptualizes fandom as a dynamic assemblage of audience, media and text.
Chapter 1 opens by asking what is a fan, which I resolve through the introduction of cultural techniques, and subsequently, my networked model of fandom. I also consider how cultural techniques research might expand to include ethnography. Chapter 2 lays out the main findings of my interview. Particularly, I examine how aging intersects with reception, how fans re-enact the distinction between German and Italian opera, and the joy of opera as an explicitly performance art. Chapter 3 tackles the dual description of Wagner as both âworkâ and âoverwhelming.â By taking seriously Theodor Adornoâs criticism, I illustrate how his music and rhetoric exert their agency onto fans. The final chapter studies the materiality of reception. Employing the metaphor of Michel Serresâ parasite, I analyze how the media which host opera shape reception through an examination of the role of the theatre, and by tracking mentions of Wagner in Torontoâs Globe newspaper in the years 1875â1876
ValidaciĂłn concurrente y de constructo de una escala para valorar el esfuerzo percibido de hombres jĂłvenes durante el ciclismo acuĂĄtico
Se ha recomendado la actividad fĂsica en el medio acuĂĄtico con colocaciĂłn vertical del cuerpo en una variedad de programas y actividades de ejercicio fĂsico debido a sus positivos beneficios relacionados con la salud y el rendimiento fĂsico. Esto ha atraĂdo y aumentado el nĂșmero de individuos aparentemente sanos de diferentes grupos de edad y sexo, e, incluso, aquellos con necesidades especiales que realizan ejercicios en el medio acuĂĄtico. AdemĂĄs de las ventajas del entrenamiento en el medio acuĂĄtico para el acondicionamiento fĂsico general, se ha producido una expansiĂłn en el universo del âaqua fitnessâ debido a la apariciĂłn de varios tipos de equipos o materiales desarrollados para potenciar los beneficios de las propiedades fĂsicas especĂficas del agua. Fruto de la aceptaciĂłn de los materiales destinados al acondicionamiento fĂsico en el medio acuĂĄtico en posiciones verticales, se han adaptado incluso otros equipos/materiales que hasta la fecha eran mĂĄs propios del medio terrestre, como por ejemplo asĂ son las bicicletas acuĂĄticas, el âaqua stepâ, los mini trampolines, las cintas de correr, los âaqua postesâ, los remos y mĂĄquinas elĂpticas, etc. En este sentido, el ciclismo acuĂĄtico es una forma de acondicionamiento fĂsico que puede incorporar personas interesadas en mantener o mejorar, entre otros aspectos, la aptitud cardiorrespiratoria. Sabiendo que este tipo de actividad puede ser aplicable a todos los grupos de edad y niveles de acondicionamiento fĂsico. En general, es conocido que para que se pueda conseguir una mejor prescripciĂłn, control y seguridad del ejercicio fĂsico, los parĂĄmetros mĂĄs utilizados para monitorizar la intensidad durante las sesiones y/o actividades suelen ser la frecuencia cardĂaca (FC) y las calificaciones o ratios del carĂĄcter del esfuerzo percibido (RPE) durante la realizaciĂłn de ejercicio fĂsico. Para monitorizar la RPE durante el ejercicio fĂsico se ha aplicado habitualmente la escala de Borg (1982) y, en base a ella, se han validado otras escalas para diferentes grupos de edad y tipos de ejercicios, aplicables muchas de ellas tanto al ĂĄmbito del fitness como a ĂĄreas clĂnicas. Dichas escalas han sido validadas para ejercicios en tierra tras establecer su adecuaciĂłn mediante correlaciones con diversas variables fisiolĂłgicas. Sin embargo, todavĂa no existe una escala de RPE especĂficamente validada para el ciclismo desarrollado en el medio acuĂĄtico. Por tanto, la presente tesis tuvo como objetivo validar una escala de tasa de esfuerzo percibido para controlar la intensidad durante el ciclismo acuĂĄtico desarrollado por hombres jĂłvenes, sanos y en forma. Por tanto, en este estudio, treinta hombres jĂłvenes, sanos y fĂsicamente activos realizaron un protocolo de cicloergĂłmetro acuĂĄtico con aumento progresivo de la carga. La validez concurrente se estableciĂł correlacionando la Escala de Ciclismo AcuĂĄtico (ECA) con la captaciĂłn de oxĂgeno, la ventilaciĂłn pulmonar (VE), la FC y las respuestas de concentraciĂłn de lactato en sangre (LS) a la prueba de carga incremental mĂĄxima. La validez de constructo se estableciĂł correlacionando la RPE derivada de la ECA (0-10) con la obtenida con la Escala de Borg (6-20). Se midiĂł la RPE general, el consumo mĂĄximo de oxĂgeno (VO2mĂĄx), el consumo de oxĂgeno indexado al peso corporal (VO2), VE, FC y LS durante cada etapa del ejercicio. El rango de respuestas al ejercicio en la prueba incremental fue: VO2mĂĄx = 1.07â3.55 L / min; VO2 = 14.26â46.89 ml / Kg / min; VE = 23.17â138.57 L / min; FC = 99.54â173.31 latidos / min; BL = 1,18-11,63 mM; ECA global = 1,11-9,33. Los anĂĄlisis de correlaciĂłn / regresiĂłn mostraron la ECA como una funciĂłn lineal positiva de VO2max (r = 0.78; p <0.05), VO2 (r = 0.87; p <0.05), VE (r = 0.86; p <0.05), HR (r = 0,77; p <0,05) y BL (r = 0,85; p <0,05). La ECA se mostrĂł distribuida como una funciĂłn lineal positiva de la escala RPE-Borg (r = 0,97; p <0,05). El ANOVA indicĂł que una cadencia de pedaleo incremental de 15 batidos por minuto (bpm) provocĂł diferencias significativas (p <0.05) con respecto a etapas previas en la mayorĂa de las variables analizadas. En conclusiĂłn, la ECA es una herramienta apropiada para monitorizar la intensidad del esfuerzo durante el ciclismo desarrollado en el medio acuĂĄtico en hombres jĂłvenes, sanos y en forma. De manera aplicada se observĂł que un breve incremento en la cadencia de pedaleo acuĂĄtico de 15 bpm aumentarĂĄ la intensidad del ejercicio durante el pedaleo acuĂĄtico.Physical activity in the aquatic environment with vertical body positioning has been recommended in a variety of physical exercise programs and activities due to its positive health and physical performance benefits. This has attracted and increased the number of apparently healthy individuals of different age groups and sex, and even those with special needs who exercise in the aquatic environment. In addition to the advantages of training in the aquatic environment for general physical conditioning, there has been an expansion in the universe of "aqua fitness" due to the appearance of various types of equipment developed to enhance the benefits of the specific physical properties of water. As a result of the acceptance of materials intended for physical conditioning in the aquatic environment in vertical positions, even other equipment/materials that to date were more typical of the land environment have been adapted, such as aquatic bicycles, the aqua step, mini trampolines, treadmills, aqua poles, oars and elliptical machines, etc. In this sense, water cycling is a form of physical conditioning that can be incorporated by people interested in maintaining or improving, among other aspects, cardiorespiratory fitness. Knowing that this type of activity can be applicable to all age groups and levels of physical conditioning. In general, it is known that in order to achieve a better prescription, control and safety of physical exercise, the most used parameters to monitor intensity during sessions and / or activities are usually the heart rate (HR) and the ratings or ratios of the character of the perceived exertion (RPE) during the realization of physical exercise. To monitor RPE during physical exercise, the Borg (1982) scale has been applied and based on it, other scales have been validated for different age groups and types of exercises, many of them applicable both to the field of fitness as well as clinical areas. These scales have been validated for exercises on land after establishing their adequacy through correlations with various physiological variables. However, there is still not specifically validated RPE scale for cycling developed in the aquatic environment. Therefore, the present thesis aims to validate a scale of perceived exertion rate to control the intensity during water cycling developed by young, healthy and fit men. Therefore, in this study, thirty young, healthy and physically active men performed a water cycle ergometer protocol with progressively increasing load. Concurrent validity was established by correlating the Aquatic Cycling Scale (ACS) with oxygen uptake, pulmonary ventilation (VE), HR, and blood lactate concentration (BL) responses to the maximal load incremental test. Construct validity was established by correlating the RPE derived from the ACS (0-10) with that obtained with the Borg Scale (6-20). Overall RPE, maximal oxygen uptake (VO2max), body weight indexed oxygen uptake (VO2), VE, HR, and BL were measured during each stage of exercise. The range of responses to exercise in the incremental test was: VO2max = 1.07â3.55 L/min; VO2 = 14.26-46.89 ml/Kg /min; VE = 23.17-138.57 L/min; HR = 99.54â173.31 beats/min; BL = 1.18-11.63 mM; Global RCT = 1.11-9.33. Correlation/ regression analyzes showed ACE as a positive linear function of VO2max (r = 0.78; p <0.05), VO2 (r = 0.87; p <0.05), VE (r = 0.86; p <0.05), HR (r = 0.77; p <0.05) and BL (r = 0.85; p <0.05). The ACE was distributed as a positive linear function of the RPE-Borg scale (r = 0.97; p <0.05). The ANOVA indicated that an incremental pedaling cadence of 15 beats per minute (bpm) caused significant differences (p <0.05) with respect to previous stages in most of the variables analyzed. In conclusion, the ACS is an appropriate tool to monitor the intensity of effort during cycling developed in the aquatic environment in young, healthy and fit men. In an applied way, it was observed that a brief increase in the water pedaling cadence of 15 bpm will increase the intensity of the exercise during water pedaling
Mouldable Solids: Exploring Organisational Grid Strategies to Enhance Mud Architecture
Mud is a material with deep origins in human ecology and vernacular architecture. Despite housing one-third of the worldâs population and almost half in developing countries, the application of mud as a building material has diminished over the years, perhaps due to a worldwide application of industrialised building materials and practices, as well as the perception of mud as a primitive material. On the contrary, mud is cheap, reusable and sustainable yet critical challenges relate to material behaviour and performance. The researcher takes the standpoint that mud architecture is a material practice and explores organisational grids consisting of skin and skeleton to enhance structural performance.
Three areas of interest combine to demonstrate how mud as a material operates in a contemporary context: (1) The Natural Philosophy of Aristotle and ibn Sina to understand the transitional state of matter and force-form relations; (2) Isaac Newtonâs Laws of Motion and Hookeâs Law to understand force-displacement relationships; (3) Information theory to represent parameters and conditions as information in organisational strategies. While mud is of interest, other materials explored include plastic, concrete, clay, and adobe as they categorise as mouldable solids due to their transitional states. Where a careful focus on mud regarding material, form, motion and force, the research deploys the technical with the philosophical to negotiate the capacities of this particular mouldable solid. The hypothesis is that the greater the variance in the skin and skeleton grid, the better the resilience and adaptability a body has due to the complex interconnections between the parts that make up a whole, organising and re-organising to withstand forces.
The dissertation celebrates mud as a reconfigurable architectural material rather than static and outdated, allowing for a multi-approach solution to contemporary and standardised materials in the current industrialised context
Evaluating footwear âin the wildâ: Examining wrap and lace trail shoe closures during trail running
Trail running participation has grown over the last two decades. As a result, there have been an increasing number of studies examining the sport. Despite these increases, there is a lack of understanding regarding the effects of footwear on trail running biomechanics in ecologically valid conditions. The purpose of our study was to evaluate how a Wrap vs. Lace closure (on the same shoe) impacts running biomechanics on a trail. Thirty subjects ran a trail loop in each shoe while wearing a global positioning system (GPS) watch, heart rate monitor, inertial measurement units (IMUs), and plantar pressure insoles. The Wrap closure reduced peak foot eversion velocity (measured via IMU), which has been associated with fit. The Wrap closure also increased heel contact area, which is also associated with fit. This increase may be associated with the subjective preference for the Wrap. Lastly, runners had a small but significant increase in running speed in the Wrap shoe with no differences in heart rate nor subjective exertion. In total, the Wrap closure fit better than the Lace closure on a variety of terrain. This study demonstrates the feasibility of detecting meaningful biomechanical differences between footwear features in the wild using statistical tools and study design. Evaluating footwear in ecologically valid environments often creates additional variance in the data. This variance should not be treated as noise; instead, it is critical to capture this additional variance and challenges of ecologically valid terrain if we hope to use biomechanics to impact the development of new products
Asymmetry measures for quantification of mechanisms contributing to dynamic stability during stepping-in-place gait
The goal of this study is to introduce and to motivate the use of new quantitative methods to improve our understanding of mechanisms that contribute to the control of dynamic balance during gait. Dynamic balance refers to the ability to maintain a continuous, oscillating center-of-mass (CoM) motion of the body during gait even though the CoM frequently moves outside of the base of support. We focus on dynamic balance control in the frontal plane or medialâlateral (ML) direction because it is known that active, neurally-mediated control mechanisms are necessary to maintain ML stability. Mechanisms that regulate foot placement on each step and that generate corrective ankle torque during the stance phase of gait are both known to contribute to the generation of corrective actions that contribute to ML stability. Less appreciated is the potential role played by adjustments in step timing when the duration of the stance and/or swing phases of gait can be shortened or lengthened to allow torque due to gravity to act on the body CoM over a shorter or longer time to generate corrective actions. We introduce and define four asymmetry measures that provide normalized indications of the contribution of these different mechanisms to gait stability. These measures are âstep width asymmetryâ, âankle torque asymmetryâ, âstance duration asymmetryâ, and âswing duration asymmetryâ. Asymmetry values are calculated by comparing corresponding biomechanical or temporal gait parameters from adjacent steps. A time of occurrence is assigned to each asymmetry value. An indication that a mechanism is contributing to ML control is obtained by comparing asymmetry values to the ML body motion (CoM angular position and velocity) at the time points associated with the asymmetry measures. Example results are demonstrated with measures obtained during a stepping-in-place (SiP) gait performed on a stance surface that either remained fixed and level or was pseudorandomly tilted to disturb balance in the ML direction. We also demonstrate that the variability of asymmetry measures obtained from 40 individuals during unperturbed, self-paced SiP were highly correlated with corresponding coefficient of variation measures that have previously been shown to be associated with poor balance and fall risk
The development of clinical interventions for knee injury management, using a novel cooling, heating, and compression device
Background: Cryotherapy and compression are advised within guidelines for injury management. However, optimum methods of applying cryotherapy have not been defined and authors have advocated a âpersonalisedâ intervention approach. With a novel cooling, heating, and compression device (CHCD) offering control of temperature and compression, it is possible to explore the effect of a range of interventions for knee injury management.
Methods & Results: Study 1 explored four 20-minute CHCD interventions on skin surface temperature (Tsk), oxygenation, thermal sensation/comfort, muscle strength, pressure pain threshold (PPT) and joint position sense (JPS), in a randomised crossover design on 26 healthy male subjects. The four interventions were: 1) 10 °C & 50 mmHg 2) 15 °C & 50 mmHg 3) 10 °C & 32 mmHg 4) alternating 10-40 °C & 25-50 mmHg. Interventions set at 10 °C achieved Tsk within the therapeutic range. Despite no significant differences in Tsk between the two compression settings, intervention 1 was perceived to be the coldest.
Study 2 investigated the effects of two 20-minute interventions, A) wetted ice and B) CHCD (10 °C & 50 mmHg), on quadriceps strength, PPT, JPS and participant-perceived pain, in 10 healthy participants with experimentally induced knee pain. Complete pain relief (â„93% reduction) was achieved immediately post-cooling in 7 participants for the CHCD and in 4 participants for ice. Significant increases in PPT were found following the CHCD, up to 20-minutes post-cooling. Ice reduced strength by 13% immediately post-cooling, however the CHCD had a negligible effect on strength post-cooling (+0.3%). Significant increases were found in range of motion in the coronal plane following ice, indicating increased instability.
Study 3 investigated the effects of A) wetted ice and B) CHCD (10 °C & 50 mmHg), on participant-reported pain, swelling and stability, through a series of 11 single-case experiments, using an alternating treatment design. The CHCD intervention achieved clinically important changes more frequently than the ice intervention for patient-reported pain (by 9%), swelling (by 21%) and patient-reported stability (by 3%).
Conclusion: Compressive cryotherapy using the CHCD at 10 °C with 50 mmHg, appeared more beneficial for the majority (82%) of individuals with knee injuries, for reducing swelling and pain, compared to ice. Targeted compressive cryotherapy, using the novel CHCD, may contribute to greater clinical management of knee injuries
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