439 research outputs found

    نقش شبیه سازها در رژیونال آنستزی واقدامات مداخله ای درد

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    اين مقاله به معرفي شبيه سازهاي پزشكي در آموزش رژيونال آنستزي و اقدامات مداخلهاي درد و روش استفاده از آن درمحي طهاي مجازي مي پردازد. ساختمانهاي طراحي شده به گونهاي پردازش شدهاند كه بازتابي واقعي از آناتومي بدن انسان باشند. سهم اصلي اين شبيهسازها، تقليد انتقال ايمپالس الكتريكي از طريق بافت نرم و طناب نخاعي است. استفاده از شبيهسازها سبب تعاملي قابل قبول، تجسم و احساسي اطمينان بخش به پزشك ميگردد. استفاده از شبيهسازها توسط دستياران تخصصي ارزيابي و نتايج رضايتبخشي داشته است. بعنوان مثال، سناريوي بلوك اندام تحتاني و شبكه سلياك توضيح داده ميشود

    Aerospace medicine and biology: A continuing bibliography with indexes (supplement 383)

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    This bibliography lists 100 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System during Nov. 1992. Subject coverage includes the following topics: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

    Human Machine Interfaces for Teleoperators and Virtual Environments

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    In Mar. 1990, a meeting organized around the general theme of teleoperation research into virtual environment display technology was conducted. This is a collection of conference-related fragments that will give a glimpse of the potential of the following fields and how they interplay: sensorimotor performance; human-machine interfaces; teleoperation; virtual environments; performance measurement and evaluation methods; and design principles and predictive models

    Techniques of EMG signal analysis: detection, processing, classification and applications

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    Electromyography (EMG) signals can be used for clinical/biomedical applications, Evolvable Hardware Chip (EHW) development, and modern human computer interaction. EMG signals acquired from muscles require advanced methods for detection, decomposition, processing, and classification. The purpose of this paper is to illustrate the various methodologies and algorithms for EMG signal analysis to provide efficient and effective ways of understanding the signal and its nature. We further point up some of the hardware implementations using EMG focusing on applications related to prosthetic hand control, grasp recognition, and human computer interaction. A comparison study is also given to show performance of various EMG signal analysis methods. This paper provides researchers a good understanding of EMG signal and its analysis procedures. This knowledge will help them develop more powerful, flexible, and efficient applications

    The evolutionary emergence of neural organisation in computational models of primitive organisms

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    Over the decades, the question why did neural organisation emerge in the way that it did? has proved to be massively elusive. Whilst much of the literature paints a picture of common ancestry the idea that a species at the root of the tree of nervous system evolution spawned numerous descendants the actual evolutionary forces responsible for such changes, major transitions or otherwise, have been less clear. The view presented in this thesis is that via interactions with the environment, neural organisation has emerged in concert with the constraints enforced by body plan morphology and a need to process information eciently and robustly. Whilst these factors are two smaller parts of a much greater whole, their impact during the evolutionary process cannot be ignored, for they are fundamentally signicant. Thus computer simulations have been developed to provide insight into how neural organisation of an articial agent should emerge given the constraints of its body morphology, its symmetry, feedback from the environment, and a loss of energy. The first major finding is that much of the computational process of the nervous system can be ooaded to the body morphology, which has a commensurate bearing on neural architecture, neural dynamics and motor symmetry. The second major finding is that sensory feedback strengthens the dynamic coupling between the neural system and the body plan morphology, resulting in minimal neural circuitry yet more ecient agent behaviour. The third major finding is that under the constraint of energy loss, neural circuitry again emerges to be minimalistic. Throughout, an emphasis is placed on the coupling between the nervous system and body plan morphology which are known in the literature to be tightly integrated; accordingly, both are considered on equal footings

    Haptics Rendering and Applications

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    There has been significant progress in haptic technologies but the incorporation of haptics into virtual environments is still in its infancy. A wide range of the new society's human activities including communication, education, art, entertainment, commerce and science would forever change if we learned how to capture, manipulate and reproduce haptic sensory stimuli that are nearly indistinguishable from reality. For the field to move forward, many commercial and technological barriers need to be overcome. By rendering how objects feel through haptic technology, we communicate information that might reflect a desire to speak a physically- based language that has never been explored before. Due to constant improvement in haptics technology and increasing levels of research into and development of haptics-related algorithms, protocols and devices, there is a belief that haptics technology has a promising future

    Injury induced neuroplasticity and cell specific targeting of the lumbar enlargement for gene therapy.

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    This dissertation is an examination of spinal cord injury induced neuroplasticity and tests whether noninvasive gene therapy can successfully target neurons in the lumbar spinal cord. It begins with an overview of neural control of locomotion and a brief summary of therapeutics that are used and/or in development for treating spinal anatomically characterize s subset of neurons in the spinal cord, long ascending propriospinal neurons, that are involved in interlimb coordination. Characterization of these neurons allows for subsequent evaluation of their potential involvement in injury induced neuroplasticity. This dissertation is divided into five chapters, covering spinal cord injury and therapeutics. Chapter One gives background on locomotor control, propriospinal neurons, spinal cord injury, and therapeutics. Chapter Two develops and characterizes viral tracing methods for spinal cord anatomy. Chapter Three then uses these methods to characterize long ascending propriospinal neurons and evaluate their involvement in injury induced plasticity. Chapter Four then focuses on the development of noninvasive delivery of gene transfer to the lumbar enlargement. This involves optimizing focused ultrasound and intravenous microbubble delivery to focally and transiently permeabilize the blood spinal cord barrier of the lumbar spinal cord. This optimization then allows for successful gene transfer in neurons in the lumbar spinal cord following intravenous delivery of viral vector. Lasty, Chapter Five discusses the implications for all of these findings and how these findings have contributed to our understanding spinal cord anatomy and injury, and how the proof-of-concept in Chapter 4 provides a promising new avenue for spinal cord injury therapeutics

    Aspects of room acoustics, vision and motion in the human auditory perception of space

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    The human sense of hearing contributes to the awareness of where sound-generating objects are located in space and of the environment in which the hearing individual is located. This auditory perception of space interacts in complex ways with our other senses, can be both disrupted and enhanced by sound reflections, and includes safety mechanisms which have evolved to protect our lives, but can also mislead us. This dissertation explores some selected topics from this wide subject area, mostly by testing the abilities and subjective judgments of human listeners in virtual environments. Reverberation is the gradually decaying persistence of sounds in an enclosed space which results from repeated sound reflections at surfaces. The first experiment (Chapter 2) compared how strongly people perceived reverberation in different visual situations: when they could see the room and the source which generated the sound; when they could see some room and some sound source, but the image did not match what they heard; and when they could not see anything at all. There were no indications that the visual image had any influence on this aspect of room-acoustical perception. The potential benefits of motion for judging the distance of sound sources were the focus of the second study (Chapter 3), which consists of two parts. In the first part, loudspeakers were placed at different depths in front of sitting listeners who, on command, had to either remain still or move their upper bodies sideways. This experiment demonstrated that humans can exploit motion parallax (the effect that closer objects appear faster to a moving observer than farther objects) with their ears and not just with their eyes. The second part combined a virtualisation of such sound sources with a motion platform to show that the listeners’ interpretation of this auditory motion parallax was better when they performed this lateral movement by themselves, rather than when they were moved by the apparatus or were not actually in motion at all. Two more experiments were concerned with the perception of sounds which are perceived as becoming louder over time. These have been called “looming”, as the source of such a sound might be on a collision course. One of the studies (Chapter 4) showed that western diamondback rattlesnakes (Crotalus atrox) increase the vibration speed of their rattle in response to the approach of a threatening object. It also demonstrated that human listeners perceive (virtual) snakes which engage in this behaviour as especially close, causing them to keep a greater margin of safety than they would otherwise. The other study (section 5.6) was concerned with the well-known looming bias of the sound localisation system, a phenomenon which leads to a sometimes exaggerated, sometimes more accurate perception of approaching compared to receding sounds. It attempted to find out whether this bias is affected by whether listeners hear such sounds in a virtual enclosed space or in an environment with no sound reflections. While the results were inconclusive, this experiment is noteworthy as a proof of concept: It was the first study to make use of a new real-time room-acoustical simulation system, liveRAZR, which was developed as part of this dissertation (Chapter 5). Finally, while humans have been more often studied for their unique abilities to communicate with each other and bats for their extraordinary capacity to locate objects by sound, this dissertation turns this setting of priorities on its head with the last paper (Chapter 6): Based on recordings of six pale spear-nosed bats (Phyllostomus discolor), it is a survey of the identifiably distinct vocalisations observed in their social interactions, along with a description of the different situations in which they typically occur.Das menschliche Gehör trägt zum Bewusstsein dafür bei, wo sich schallerzeugende Objekte im Raum befinden und wie die Umgebung beschaffen ist, in der sich eine Person aufhält. Diese auditorische Raumwahrnehmung interagiert auf komplexe Art und Weise mit unseren anderen Sinnen, kann von Schallreflektionen sowohl profitieren als auch durch sie behindert werden, und besitzt Mechanismen welche evolutionär entstanden sind, um unser Leben zu schützen, uns aber auch irreführen können. Diese Dissertation befasst sich mit einigen ausgewählten Themen aus diesem weiten Feld und stützt sich dabei meist auf die Testung von Wahrnehmungsfähigkeiten und subjektiver Einschätzungen menschlicher Hörer/-innen in virtueller Realität. Beim ersten Experiment (Kapitel 2) handelte es sich um einen Vergleich zwischen der Wahrnehmung von Nachhall, dem durch wiederholte Reflexionen an Oberflächen hervorgerufenen, sukzessiv abschwellenden Verbleib von Schall in einem umschlossenen Raum, unter verschiedenen visuellen Umständen: wenn die Versuchsperson den Raum und die Schallquelle sehen konnte; wenn sie irgendeinen Raum und irgendeine Schallquelle sehen konnte, dieses Bild aber vom Schalleindruck abwich; und wenn sie gar kein Bild sehen konnte. Dieser Versuch konnte keinen Einfluss eines Seheindrucks auf diesen Aspekt der raumakustischen Wahrnehmung zu Tage fördern. Mögliche Vorteile von Bewegung für die Einschätzung der Entfernung von Schallquellen waren der Schwerpunkt der zweiten Studie (Kapitel 3). Diese bestand aus zwei Teilen, wovon der erste zeigte, dass Hörer/-innen, die ihren Oberkörper relativ zu zwei in unterschiedlichen Abständen vor ihnen aufgestellten Lautsprechern auf Kommando entweder stillhalten oder seitlich bewegen mussten, im letzteren Falle von der Bewegungsparallaxe (dem Effekt, dass sich der nähere Lautsprecher relativ zum sich bewegenden Körper schneller bewegte als der weiter entfernte) profitieren konnten. Der zweite Teil kombinierte eine Simulation solcher Schallquellen mit einer Bewegungsplattform, wodurch gezeigt werden konnte, dass die bewusste Eigenbewegung für die Versuchspersonen hilfreicher war, als durch die Plattform bewegt zu werden oder gar nicht wirklich in Bewegung zu sein. Zwei weitere Versuche gingen auf die Wahrnehmung von Schallen ein, deren Ursprungsort sich nach und nach näher an den/die Hörer/-in heranbewegte. Derartige Schalle werden auch als „looming“ („anbahnend“) bezeichnet, da eine solche Annäherung bei bedrohlichen Signalen nichts Gutes ahnen lässt. Einer dieser Versuche (Kapitel 4) zeigte zunächst, dass Texas-Klapperschlangen (Crotalus atrox) die Vibrationsgeschwindigkeit der Schwanzrassel steigern, wenn sich ein bedrohliches Objekt ihnen nähert. Menschliche Hörer/-innen nahmen (virtuelle) Schlangen, die dieses Verhalten aufweisen, als besonders nahe wahr und hielten einen größeren Sicherheitsabstand ein, als sie es sonst tun würden. Der andere Versuch (Abschnitt 5.6) versuchte festzustellen, ob die wohlbekannte Neigung unserer Schallwahrnehmung, näherkommende Schalle manchmal übertrieben und manchmal genauer einzuschätzen als sich entfernende, durch Schallreflektionen beeinflusst werden kann. Diese Ergebnisse waren unschlüssig, jedoch bestand die Besonderheit dieses Versuchs darin, dass er erstmals ein neues Echtzeitsystem zur Raumakustiksimulation (liveRAZR) nutzte, welches als Teil dieser Dissertation entwickelt wurde (Kapitel 5). Abschließend (Kapitel 6) wird die Schwerpunktsetzung auf den Kopf gestellt, nach der Menschen öfter auf ihre einmaligen Fähigkeiten zur Kommunikation miteinander untersucht werden und Fledermäuse öfter auf ihre außergewöhnliches Geschick, Objekte durch Schall zu orten: Anhand von Aufnahmen von sechs Kleinen Lanzennasen (Phyllostomus discolor) fasst das Kapitel die klar voneinander unterscheidbaren Laute zusammen, die diese Tiere im sozialen Umgang miteinander produzieren, und beschreibt, in welchen Situationen diese Lauttypen typischerweise auftreten
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