531 research outputs found

    Upregtilation of neuronal α7 nicotinic acetylcholine receptors and preconditioning

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    The upregulation of alpha 7 nicotinic acetylcholine receptors (α7 nAChRs) are putatively reported to play a role in in vivo cortical spreading depression-elicited neuroprotection. In this study, a reliable in vitro spreading depression model was created for studying this phenomenon. In contradiction to previous studies, it was, however, shown that functional α 7 nAChRs are down-regulated upon chronic depolarisation with KCl, although the activity of this receptor subtype remained essential for the preconditioning mechanism. Evidence was provided for a differential mechanism underlying protection against NMDA-mediated and hypotonic-shock induced cell loss. Non-pharmacological upregulation of the α 7 nAChRs in pure neuronal cortical cultures by means of a recombinant adenovirus led to the increased cell death subsequent to an excitotoxic glutamate insult. In addition, in order to study the relationship between α7 nAChRs and its function-dependent regulator Ric3, a novel anti-Ric3 antibody and a recombinant adenovirus expressing the ric3 gene were created. Ric3 was found to be expressed in many important brain structures, including hippocampus, perhinal cortex, thalamic and hypothalamic paraventricular nucleus, structures implicated in both cognitive and emotional behaviours. Interestingly, Ric3 was also expressed in the choroid plexus, a non-neuronal cell type not known to α 7 nAChRs, indicating additional roles for this protein. The recombinant constructs expressing ric3, α 7 nAChRs and dual ric3/ α 7 nAChRs were all validated in vitro

    Eye Detection and Face Recognition Across the Electromagnetic Spectrum

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    Biometrics, or the science of identifying individuals based on their physiological or behavioral traits, has increasingly been used to replace typical identifying markers such as passwords, PIN numbers, passports, etc. Different modalities, such as face, fingerprint, iris, gait, etc. can be used for this purpose. One of the most studied forms of biometrics is face recognition (FR). Due to a number of advantages over typical visible to visible FR, recent trends have been pushing the FR community to perform cross-spectral matching of visible images to face images from higher spectra in the electromagnetic spectrum.;In this work, the SWIR band of the EM spectrum is the primary focus. Four main contributions relating to automatic eye detection and cross-spectral FR are discussed. First, a novel eye localization algorithm for the purpose of geometrically normalizing a face across multiple SWIR bands for FR algorithms is introduced. Using a template based scheme and a novel summation range filter, an extensive experimental analysis show that this algorithm is fast, robust, and highly accurate when compared to other available eye detection methods. Also, the eye locations produced by this algorithm provides higher FR results than all other tested approaches. This algorithm is then augmented and updated to quickly and accurately detect eyes in more challenging unconstrained datasets, spanning the EM spectrum. Additionally, a novel cross-spectral matching algorithm is introduced that attempts to bridge the gap between the visible and SWIR spectra. By fusing multiple photometric normalization combinations, the proposed algorithm is not only more efficient than other visible-SWIR matching algorithms, but more accurate in multiple challenging datasets. Finally, a novel pre-processing algorithm is discussed that bridges the gap between document (passport) and live face images. It is shown that the pre-processing scheme proposed, using inpainting and denoising techniques, significantly increases the cross-document face recognition performance

    Pertanika Journal of Science & Technology

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    Abstracts of Papers, 79th Annual Meeting of the Virginia Academy of Science, May 22-25, 2001, James Madison University, Harrisonburg, Virginia

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    Abstracts of papers that were presented at the 79th Annual Meeting of the Virginia Academy of Science, May 22-25, 2001, James Madison University, Harrisonburg, Virginia

    Pertanika Journal of Science & Technology

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    Pertanika Journal of Science & Technology

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    Evaluation of Detecting Cybersickness via VR HMD Positional Measurements Under Realistic Usage Conditions.

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    With the resurgence of virtual reality, head-mounted displays (VR HMD) technologies since 2015, VR technology is becoming ever more present in people's day-to-day lives. However, one significant barrier to this progress is a condition called cybersickness, a form of motion sickness induced by the usage of VR HMD’s. It is often debilitating to sufferers, resulting in symptoms anywhere from mild discomfort to full-on vomiting. Much research effort focuses on identifying the cause of and solution to this problem, with many studies reporting various factors that influence cybersickness, such as vection and field of view. However, there is often disagreement in these studies' results and comparing the results is often complicated as stimuli used for the experiments vary wildly. This study theorised that these results' mismatch might partially be down to the different mental loads of these tasks, which may influence cybersickness and stability-based measurement methods such as postural stability captured by the centre of pressure (COP) measurements. One recurring desire in these research projects is the idea of using the HMD device itself to capture the stability of the users head. However, measuring the heads position via the VR HMD is known to have inaccuracies meaning a perfect representation of the heads position cannot be measured. This research took the HTC Vive headset and used it to capture the head position of multiple subjects experiencing two different VR environments under differing levels of cognitive load. The design of these test environments reflected normal VR usage. This research found that the VR HMD measurements in this scenario may be a suitable proxy for recording instability. However, the underlying method was greatly influenced by other factors, with cognitive load (5.4% instability increase between the low and high load conditions) and test order (2.4% instability decrease between first run and second run conditions) having a more significant impact on the instability recorded than the onset of cybersickness (2% instability increase between sick and well participants). Also, separating participants suffering from cybersickness from unaffected participants was not possible based upon the recorded motion alone. Additionally, attempts to capture stability data during actual VR gameplay in specific areas of possible head stability provided mixed results and failed to identify participants exhibiting symptoms of cybersickness successfully. In conclusion, this study finds that while a proxy measurement for head stability is obtainable from an HTC Vive headset, the results recorded in no way indicate cybersickness onset. Additionally, the study proves cognitive load and test order significantly impact stability measurements recorded in this way. As such, this approach would need calibration on a case-by-case basis if used to detect cybersickness

    Watching Androids Dream of Electric Sheep: Immersive Technology, Biometric Psychography, and the Law

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    Virtual reality and augmented reality present exceedingly complex privacy issues because of the enhanced user experience and reality-based models. Unlike the issues presented by traditional gaming and social media, immersive technology poses inherent risks, which our legal understanding of biometrics and online harassment is simply not prepared to address. This Article offers five important contributions to this emerging space. It begins by introducing a new area of legal and policy inquiry raised by immersive technology called “biometric psychography.” Second, it explains how immersive technology works to a legal audience and defines concepts that are essential to understanding the risks that the technology poses. Third, it analyzes the gaps in privacy law to address biometric psychography and other emerging challenges raised by immersive technology that most regulators and consumers incorrectly assume will be governed by existing law. Fourth, this Article sources firsthand interviews from early innovators and leading thinkers to highlight harassment and user experience risks posed by immersive technology. Finally, this Article compiles insights from each of these discussions to propose a framework that integrates privacy and human rights into the development of future immersive tech applications. It applies that framework to three specific scenarios and demonstrates how it can help navigate challenges, both old and new

    Biometric Systems

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    Because of the accelerating progress in biometrics research and the latest nation-state threats to security, this book's publication is not only timely but also much needed. This volume contains seventeen peer-reviewed chapters reporting the state of the art in biometrics research: security issues, signature verification, fingerprint identification, wrist vascular biometrics, ear detection, face detection and identification (including a new survey of face recognition), person re-identification, electrocardiogram (ECT) recognition, and several multi-modal systems. This book will be a valuable resource for graduate students, engineers, and researchers interested in understanding and investigating this important field of study
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