904 research outputs found

    An analogue approach for the processing of biomedical signals

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    Constant device scaling has signifcantly boosted electronic systems design in the digital domain enabling incorporation of more functionality within small silicon area and at the same time allows high-speed computation. This trend has been exploited for developing high-performance miniaturised systems in a number of application areas like communication, sensor network, main frame computers, biomedical information processing etc. Although successful, the associated cost comes in the form of high leakage power dissipation and systems reliability. With the increase of customer demands for smarter and faster technologies and with the advent of pervasive information processing, these issues may prove to be limiting factors for application of traditional digital design techniques. Furthermore, as the limit of device scaling is nearing, performance enhancement for the conventional digital system design methodology cannot be achieved any further unless innovations in new materials and new transistor design are made. To this end, an alternative design methodology that may enable performance enhancement without depending on device scaling is much sought today.Analogue design technique is one of these alternative techniques that have recently gained considerable interests. Although it is well understood that there are several roadblocks still to be overcome for making analogue-based system design for information processing as the main-stream design technique (e.g., lack of automated design tool, noise performance, efficient passive components implementation on silicon etc.), it may offer a faster way of realising a system with very few components and therefore may have a positive implication on systems performance enhancement. The main aim of this thesis is to explore possible ways of information processing using analogue design techniques in particular in the field of biomedical systems

    HYPOTHALAMIC CIRCUITS IN THE CONTROL OF FEEDING AND EMOTIONAL BEHAVIORS

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    Feeding results from the integration of both nutritional and affective states, and is guided by complex neural circuitry in the brain. The hypothalamus is a critical center controlling feeding and motivated behaviors. We found that targeted photostimulation of projections from the lateral hypothalamus (LH) to the paraventricular hypothalamus (PVH) in mice elicited voracious feeding and repetitive self-grooming behavior. GABA neurotransmission in the LH-\u3ePVH circuit mediated the evoked feeding behavior, and elicited behavioral approach, whereas glutamate release promoted repetitive self-grooming, which was stress-related in nature. Optogenetic inhibition of LHGABA -\u3ePVH circuit reduced feeding after fasting, whereas photostimulation abruptly stopped ongoing self-grooming and immediately elicited feeding. Oppositely, optogenetic inhibition of LHGlutamate-\u3ePVH circuit reduced repetitive self-grooming, whereas photostimulation suppressed fast-refeeding in exchange for repetitive self-grooming. Optogenetically activating and silencing PVH neurons directly recapitulated these findings, and demonstrated the necessity of glutamatergic PVH neurons in mediating the competition between self-grooming and feeding. Together, these results provided evidence that the mutually exclusive nature of feeding and self-grooming behaviors are in part mediated by distinct components in the LH-\u3ePVH circuit. Interestingly, photostimulating PVH neurons with greater intensity promoted transitions from grooming to frantic escape-jumping, suggesting scalability of stress-related behaviors mediated by PVH neural activity. Because evoked jumping resembled attempts to escape, we posited PVH neurons mediate defensive responses. Validating this, photostimulating PVH neurons induced avoidance and increased locomotion, two classic behavioral indicators of active defense strategies. Anterograde tracing showed that PVH neurons densely projected to the midbrain region in and surrounding the ventral tegmental area (VTA), a brain region well-known for its roles in motivated behaviors. Indeed, photostimulation of PVH-\u3emidbrain projections produced escape behaviors and conditioned place aversion. Combined optogenetic and chemogenetic experiments showed that glutamatergic-midbrain neurons were required for escape behaviors. Further, glutamatergic-midbrain neurons displayed increased neural population activity in vivo during a fear-provoking situation, validating a role for this population in processing threat. Taken together, our work reveals novel hypothalamic circuits in the control of feeding, emotional valence, and behaviors related to stress and defense. These findings shed light on possible neural mechanisms underlying complex disease states characterized by feeding abnormalities, anxiety and fear

    Orion FSW V and V and Kedalion Engineering Lab Insight

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    NASA, along with its prime Orion contractor and its subcontractor s are adapting an avionics system paradigm borrowed from the manned commercial aircraft industry for use in manned space flight systems. Integrated Modular Avionics (IMA) techniques have been proven as a robust avionics solution for manned commercial aircraft (B737/777/787, MD 10/90). This presentation will outline current approaches to adapt IMA, along with its heritage FSW V&V paradigms, into NASA's manned space flight program for Orion. NASA's Kedalion engineering analysis lab is on the forefront of validating many of these contemporary IMA based techniques. Kedalion has already validated many of the proposed Orion FSW V&V paradigms using Orion's precursory Flight Test Article (FTA) Pad Abort 1 (PA-1) program. The Kedalion lab will evolve its architectures, tools, and techniques in parallel with the evolving Orion program

    Advanced Resistive Exercise Device (ARED) Flight Software (FSW): A Unique Approach to Exercise in Long Duration Habitats

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    ARED flight instrumentation software is associated with an overall custom designed resistive exercise system that will be deployed on the International Space Station (ISS). This innovative software application fuses together many diverse and new technologies into a robust and usable package. The software takes advantage of touchscreen user interface technology by providing a graphical user interface on a Windows based tablet PC, meeting a design constraint of keyboard-less interaction with flight crewmembers. The software interacts with modified commercial data acquisition (DAQ) hardware to acquire multiple channels of sensor measurment from the ARED device. This information is recorded on the tablet PC and made available, via International Space Station (ISS) Wireless LAN (WLAN) and telemetry subsystems, to ground based mission medics and trainers for analysis. The software includes a feature to accept electronically encoded prescriptions of exercises that guide crewmembers through a customized regimen of resistive weight training, based on personal analysis. These electronically encoded prescriptions are provided to the crew via ISS WLAN and telemetry subsystems. All personal data is securely associated with an individual crew member, based on a PIN ID mechanism

    Self Concept of Academic Ability and Reading Proficiency

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    Brookover and associates (1962, 1964, 1965) have investigated the nature of self-concept and its effects, and relationships, to the academic achievement. Results reported indicate that there is a direct relationship between self-concept and academic achievement

    Simulation/Emulation Techniques: Compressing Schedules With Parallel (HW/SW) Development

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    NASA has always been in the business of balancing new technologies and techniques to achieve human space travel objectives. NASA's Kedalion engineering analysis lab has been validating and using many contemporary avionics HW/SW development and integration techniques, which represent new paradigms to NASA's heritage culture. Kedalion has validated many of the Orion HW/SW engineering techniques borrowed from the adjacent commercial aircraft avionics solution space, inserting new techniques and skills into the Multi - Purpose Crew Vehicle (MPCV) Orion program. Using contemporary agile techniques, Commercial-off-the-shelf (COTS) products, early rapid prototyping, in-house expertise and tools, and extensive use of simulators and emulators, NASA has achieved cost effective paradigms that are currently serving the Orion program effectively. Elements of long lead custom hardware on the Orion program have necessitated early use of simulators and emulators in advance of deliverable hardware to achieve parallel design and development on a compressed schedule

    Diseño y friendly objects

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    La mirada semiótica sobre los objetos de diseño se ha vuelto muy complaciente. Es necesario volver sobre los pasos de la semiótica política del objeto en este nuevo entorno de la globalización y la táctica del objeto amigable. A través de esta metáfora coloquial y otras semejantes podríamos, de nuevo, reabrir un espacio necesario de confrontación teórica.The semiotic view on design objects has become very complacent. It is necessary to retrace the steps of the semiotics of the seventies, especially in this new environment of globalization and the tactics of the friendly-objects. Through this conversational metaphor we may reopen again a required theoretical space of confrontations

    Diseño gráfico y semiótica en Venezuela : entre historiografía y teoría

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    En este trabajo se trata de articular y conectar las producciones del diseño gráfico en el proceso educativo desde una perspectiva semiótica. Al mismo tiempo, se propone una tipología semiótica abierta para realizar nuevos estudios sobre el análisis sincrónico y diacrónico del diseño. Los objetos de diseño gráfico aquí elegidos se colocan entre una teoría semiótica y la historiografía.This paper tries to articulate and connect the productions of the graphic design in the educational process from a semiotic perspective. At the same time, we propose an open semiotic typology for further studies over synchronic and diachronic analysis of design. The graphic design's objetcs chosen here are placed between a semiotic theory and historiography

    Atlas Spielraum : a partir del site-specific como espacio de maniobras personales

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    Las labores del crítico de arte, del museógrafo y del curador pueden integrarse a través de la estrategia del Atlas Mnemosyne. El punto de partida de este ensayo es la propuesta de un site-specific que se conecta con otras series de imágenes que no pertenecen a un mismo y único contexto, pero que comparten figuras de la significación a nivel más profundo.The work of the art critic, the museographer and the curator can be integrated through the Atlas-Mnemosyne strategy. The starting point of this essay is the proposal of a site-specific that connects with other series of images that don't belong to the same and unique context, but share the figures of significance at a deep level of the visual text
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