Advanced LIGO's ability to detect apparent violations of the cosmic censorship conjecture and the no-hair theorem through compact binary coalescence detections

We study the ability of the advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) to detect apparent violations of the cosmic censorship conjecture and the no-hair theorem. The cosmic censorship conjecture, which is believed to be true in the theory of general relativity, limits the spin-to-mass-squared ratio of a Kerr black hole. The no-hair theorem, which is also believed to be true in the theory of general relativity, suggests a particular value for the tidal Love number of a non-rotating black hole. Using the Fisher matrix formalism, we examine the measurability of the spin and tidal deformability of compact binary systems involving at least one putative black hole. Using parameter measurement errors and correlations obtained from the Fisher matrix, we determine the smallest detectable violation of bounds implied by the cosmic censorship conjecture and the no-hair theorem. We examine the effect of excluding unphysical areas of parameter space when determining the smallest detectable apparent violations, and we examine the effect of different post-Newtonian corrections to the amplitude of the compact binary coalescence gravitational waveform. In addition, we perform a brief study of how the recently calculated 3.0 pN and 3.5 pN spin-orbit corrections to the phase affect spin and mass parameter measurability. We find that physical priors on the symmetric mass ratio and higher harmonics in the gravitational waveform could significantly affect the ability of aLIGO to investigate cosmic censorship and the no-hair theorem for certain systems.Comment: 21 pages, 7 figures, 6 table

Common CHD8 Genomic Targets Contrast With Model-Specific Transcriptional Impacts of CHD8 Haploinsufficiency.

The packaging of DNA into chromatin determines the transcriptional potential of cells and is central to eukaryotic gene regulation. Case sequencing studies have revealed mutations to proteins that regulate chromatin state, known as chromatin remodeling factors, with causal roles in neurodevelopmental disorders. Chromodomain helicase DNA binding protein 8 (CHD8) encodes a chromatin remodeling factor with among the highest de novo loss-of-function mutation rates in patients with autism spectrum disorder (ASD). However, mechanisms associated with CHD8 pathology have yet to be elucidated. We analyzed published transcriptomic data across CHD8 in vitro and in vivo knockdown and knockout models and CHD8 binding across published ChIP-seq datasets to identify convergent mechanisms of gene regulation by CHD8. Differentially expressed genes (DEGs) across models varied, but overlap was observed between downregulated genes involved in neuronal development and function, cell cycle, chromatin dynamics, and RNA processing, and between upregulated genes involved in metabolism and immune response. Considering the variability in transcriptional changes and the cells and tissues represented across ChIP-seq analysis, we found a surprisingly consistent set of high-affinity CHD8 genomic interactions. CHD8 was enriched near promoters of genes involved in basic cell functions and gene regulation. Overlap between high-affinity CHD8 targets and DEGs shows that reduced dosage of CHD8 directly relates to decreased expression of cell cycle, chromatin organization, and RNA processing genes, but only in a subset of studies. This meta-analysis verifies CHD8 as a master regulator of gene expression and reveals a consistent set of high-affinity CHD8 targets across human, mouse, and rat in vivo and in vitro studies. These conserved regulatory targets include many genes that are also implicated in ASD. Our findings suggest a model where perturbation to dosage-sensitive CHD8 genomic interactions with a highly-conserved set of regulatory targets leads to model-specific downstream transcriptional impacts

Is the Wind of the Galactic Oe Star HD 155806 Magnetically Confined?

Spectropolarimetric observations of HD 155806 - the hottest Galactic Oe star - were obtained with CFHT/ESPaDOnS to test the hypothesis that disk signatures in its spectrum are due to magnetic channeling and confinement of its stellar wind. We did not detect a dipole field of sufficient strength to confine the wind, and could not confirm previous reports of a magnetic detection. It appears that stellar magnetism is not responsible for producing the disk of HD 155806.Comment: 2 pages, 1 figure; to appear in the proceedings of IAU Symposium 27

Population receptive field (pRF) measurements of chromatic responses in human visual cortex using fMRI

The spatial sensitivity of the human visual system depends on stimulus color: achromatic gratings can be resolved at relatively high spatial frequencies while sensitivity to isoluminant color contrast tends to be more low-pass. Models of early spatial vision often assume that the receptive field size of pattern-sensitive neurons is correlated with their spatial frequency sensitivity - larger receptive fields are typically associated with lower optimal spatial frequency. A strong prediction of this model is that neurons coding isoluminant chromatic patterns should have, on average, a larger receptive field size than neurons sensitive to achromatic patterns. Here, we test this assumption using functional magnetic resonance imaging (fMRI). We show that while spatial frequency sensitivity depends on chromaticity in the manner predicted by behavioral measurements, population receptive field (pRF) size measurements show no such dependency. At any given eccentricity, the mean pRF size for neuronal populations driven by luminance, opponent red/green and S-cone isolating contrast, are identical. Changes in pRF size (for example, an increase with eccentricity and visual area hierarchy) are also identical across the three chromatic conditions. These results suggest that fMRI measurements of receptive field size and spatial resolution can be decoupled under some circumstances - potentially reflecting a fundamental dissociation between these parameters at the level of neuronal populations

Format(ive) Wars: Formation of the British Videogames Industry in the 1980s

ABSTRACT 'Format', 'platform' or 'console' wars are a defining characteristic of the development of a discourse of generational linear-chronology among videogame technologies. The UK is typified as the 'rarefied home of the format wars' (Wade 2007: 682), with the buoyancy of its contemporary development scene often attributed to the battles between the Commodore and Spectrum machines which were fought in the bedrooms, playgrounds and classrooms of the mid-1980s. The primacy of a format wars ideology was compounded with the early-1990s US face-off between Sega and Nintendo, which devolved into a litigious and acrimonious exchange, which arguably lead to the decline of both companies when Sony entered the marketplace in 1994. It is widely understood that format wars are both highly representative of and prevalent in post-industrial societies, where vying for market dominance is an indicator of the information age (Shapiro and Varian 1999: 8). Videogame technologies are a key signifier of this transition with their immutable reliance on technological upgrades, restrictive practices in use and publication and built-in obsolescence. Yet the lineargenerational model so favoured by videogame commentators has been extensively challenged by scholars from inside and outside the US including Guins (2014) and Newman (2012) as they are tied to a model which privileges tech-fetishism and unhelpful linear-chronological metaphors. Many of these recent methodological revisions to the format wars model foreground discourse analysis of videogame magazines (e.g. Zzap! and Crash) as the key proponent for the sociocultural formation of the industry (see especially Kirkpatrick 2015, also Therrien and Picard 2015). Whilst these are useful approaches, their narrow focus fails to acknowledge other, vitally important influences on the videogames industry in 1980s Britain. Therefore, with these revisions and caveats to the fore, this paper challenges the current research on the formation of the videogames industry in the 1980s. With strategic management literature aligning the end-user, or consumer, as the most important focus of emergent technological industries, all those involved in videogames' formation are viewed as an end users, a position contingent on their intrinsic relationships with one another. These relationships can be seen as battles, wars, or fights, but there are nuance

Extended Play: Hands on With Forty Years of English Amusement Arcades

Recent games scholarship (e.g. Guins, 2014; Newman, 2012) examines how videogames have aged over time and the risks to conservation that they face from the time increments of lack of technological capability (e.g. bitrot), rights protection (e.g. suicide chips) and unintended consequences (e.g. ultraviolet degradation). In spite of these threats, antique videogames continue to thrive both in domestic collections, and, perhaps, more surprisingly, in what Kocurek and Tobin (2014) have termed the ‘undead arcade’, the more mechanically vexing public environments of retro arcades. Theoretically positioned as a genealogical approach to the research of videogame histories (see Suominen, 2016), this chapter examines the past and present methods by which arcade games are used, preserved and presented across time and space. This is achieved via primary data from arcade workers (e.g. floorwalkers, cashiers, refectory staff) who made a living in the videogame arcades in the 1970s/1980s and continue to do so in the 2010s. Drawing on interviews and observation from individuals in arcades in the south and north of England (Happidrome and Astro City in Southend-on-Sea; Arcade Club in Bury), the chapter reveals how arcade videogames were and continue to be used and mined as a site for sub-cultural capital. Much of this draws on the site of the arcade as being a venue of grey practice. Shortcuts to play (e.g. arcing a cigarette lighter on Moon Cresta), hacks (e.g. ice-shaped 50 pence pieces in change machines) and workarounds (changing coinslots on shovellors) demonstrated mastery and prowess of the machine. These were located in - and can never be separated from - socially grey practices of sexual harassment (lifting up a woman’s skirt during a game of Donkey Kong), financial irregularity (working with the ‘faces’ to acquire cash from token machines) and the illegal propagation of ‘pop-up’ arcades, indicate an equal mastery of the intensely competitive social environment of the arcade. This continues to be the case in arcades in the 2010s, where it is almost incredulous that the antique arcade machines preserved and nurtured at Happidrome and Arcade Club by the same people who extracted maximum capital from them in the 1980s

Driving, Dashboards and Dromology: Analysing 1980s Videogames Using Paul Virilio’s Theory of Speed

The increasing speed of delivery technologies correlates with an increase in inertia for the user of the audiovisual. Employing Virilio’s concept of dromology, the first part of this paper introduces Virilio’s key concepts of speed and inertia upon the perception of space and time by the users of a range of technologies. It is argued that the privileging of ‘time-saving’ ravages traditional notions of space, and generates an additional ‘digital’ space which is at once expansive and also convexed towards the user. Having established the effects of speed and inertia, the main part of the paper extends Virilio’s theory of dromology to provide a context for analysis of a variety of seminal videogames from the 1980s, where driving is a key component. These games of dashboards and vehicles, wars and (wind)screens illustrate Virilio’s central concerns that societies that are addicted to speed are also those which are the most tightly surveilled and controlled