225 research outputs found

    Gaze-dependent topography in human posterior parietal cortex.

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    The brain must convert retinal coordinates into those required for directing an effector. One prominent theory holds that, through a combination of visual and motor/proprioceptive information, head-/body-centered representations are computed within the posterior parietal cortex (PPC). An alternative theory, supported by recent visual and saccade functional magnetic resonance imaging (fMRI) topographic mapping studies, suggests that PPC neurons provide a retinal/eye-centered coordinate system, in which the coding of a visual stimulus location and/or intended saccade endpoints should remain unaffected by changes in gaze position. To distinguish between a retinal/eye-centered and a head-/body-centered coordinate system, we measured how gaze direction affected the representation of visual space in the parietal cortex using fMRI. Subjects performed memory-guided saccades from a central starting point to locations “around the clock.” Starting points varied between left, central, and right gaze relative to the head-/body midline. We found that memory-guided saccadotopic maps throughout the PPC showed spatial reorganization with very subtle changes in starting gaze position, despite constant retinal input and eye movement metrics. Such a systematic shift is inconsistent with models arguing for a retinal/eye-centered coordinate system in the PPC, but it is consistent with head-/body-centered coordinate representations

    Of “sluts” and “arseholes”: Antagonistic desire and the production of sexual vigilance

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    This article examines a contemporary antagonism in gendered safety discourses—the imperative to be free in public space against the obligation to be safe and “properly” feminine. We argue that this produces (and is produced by) contemporary rape culture, which might be contested through recourse to an agonistic ethic. Using qualitative interview data, we examine how participants contest victim-blaming discourses, while limiting how far they will accept the female body’s right to occupy public space. This article has significant implications for approaching social justice, in particular justice for women and their right to occupy public space

    Using Variable Natural Environment Brain-Computer Interface Stimuli for Real-time Humanoid Robot Navigation

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    This paper addresses the challenge of humanoid robot teleoperation in a natural indoor environment via a Brain-Computer Interface (BCI). We leverage deep Convolutional Neural Network (CNN) based image and signal understanding to facilitate both real-time bject detection and dry-Electroencephalography (EEG) based human cortical brain bio-signals decoding. We employ recent advances in dry-EEG technology to stream and collect the cortical waveforms from subjects while they fixate on variable Steady State Visual Evoked Potential (SSVEP) stimuli generated directly from the environment the robot is navigating. To these ends, we propose the use of novel variable BCI stimuli by utilising the real-time video streamed via the on-board robot camera as visual input for SSVEP, where the CNN detected natural scene objects are altered and flickered with differing frequencies (10Hz, 12Hz and 15Hz). These stimuli are not akin to traditional stimuli - as both the dimensions of the flicker regions and their on-screen position changes depending on the scene objects detected. On-screen object selection via such a dry-EEG enabled SSVEP methodology, facilitates the on-line decoding of human cortical brain signals, via a specialised secondary CNN, directly into teleoperation robot commands (approach object, move in a specific direction: right, left or back). This SSVEP decoding model is trained via a priori offline experimental data in which very similar visual input is present for all subjects. The resulting classification demonstrates high performance with mean accuracy of 85% for the real-time robot navigation experiment across multiple test subjects.Comment: Accepted as a full paper at the 2019 International Conference on Robotics and Automation (ICRA

    LSST Science Book, Version 2.0

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    A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

    Everyday Diplomacy: UKUSA Intelligence Cooperation and Geopolitical Assemblages

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    This article offers an alternative to civilizational thinking in geopolitics and international relations predicated on assemblage theory. Building on literature in political geography and elsewhere about everyday practices that produce state effects, this article theorizes the existence of transnational geopolitical assemblages that incorporate foreign policy apparatuses of multiple states. Everyday material and discursive circulations make up these assemblages, serving as conduits of affect that produce an emergent agency. To demonstrate this claim, I outline a genealogy of the UKUSA alliance, an assemblage of intelligence communities in the United States, United Kingdom, Canada, Australia, and New Zealand. I then trace the circulation of materialities and affects—at the scales of individual subjects, technological systems of mediation, and transnational processes of foreign policy formation. In doing so, I offer a bottom-up process of assemblage that produces the emergent phenomena that proponents of civilizational thinking mistakenly attribute to macroscaled factors, such as culture
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