419 research outputs found
Altered White Matter Structure in Adults Following Early Monocular Enucleation
Visual deprivation from early monocular enucleation (the surgical removal of one eye) results in a number of long-term behavioural and morphological adaptations in the visual, auditory, and multisensory systems. This thesis aims to investigate how the loss of one eye early in life affects structural connectivity within the brain. A combination of diffusion tensor imaging and tractography was used to examine structural differences in 18 tracts throughout the brain of adult participants who had undergone early monocular enucleation compared to binocularly intact controls. We report significant structural changes to white matter in early monocular enucleation participants that extend beyond the primary visual pathway to include interhemispheric, auditory and multisensory tracts, as well as several long association fibres. Overall these results suggest that early monocular enucleation has long-term effects on white matter structure throughout the brain
Effect of Olfaction on the Perception of Movie Clips
Odours are important to many species but their effect on human perception in the context of concurrent auditory and visual stimulation has received little investigation. Here we examined how the experience of viewing audio-visual movie clips changes when accompanied by congruent or incongruent odours. Using an olfactometer to control odourant delivery, thirty-five undergraduate students from Western University were randomly presented 36 different odour-video pairs twice. Following each presentation, participants completed three Likert scales to assess multisensory interaction in terms of engagement, pleasantness, and emotional arousal. Comparison of congruent and incongruent odours to the no odour control condition revealed that incongruent odours had a greater effect than congruent odours on participant ratings, and that this effect acted to negatively influence experience, reducing engagement, pleasantness, and emotional arousal. There was little difference between congruent odours and no odour on ratings of engagement and emotional arousal; however, even congruent odours reduced pleasantness ratings, suggesting all odours used were, to an extent, unpleasant. An interaction suggested that certain movies were more strongly modulated by odour than others. We interpret our results as evidence of crossmodal competition, in which the presence of an odour leads to suppression of the auditory and visual modalities. This was confirmed using functional magnetic resonance imaging in a single participant. Future research should continue to investigate the surprising role odour plays in multisensory interaction
Altered white matter structure in auditory tracts following early monocular enucleation
Purpose: Similar to early blindness, monocular enucleation (the removal of one eye) early in life results in
crossmodal behavioral and morphological adaptations. Previously it has been shown that partial visual deprivation from early monocular enucleation results in structural white matter changes throughout the visual system (Wong et al., 2018). The current study investigated structural white matter of the auditory system in adults who have undergone early monocular enucleation compared to binocular control participants. Methods: We reconstructed four auditory and audiovisual tracts of interest using probabilistic tractography and compared microstructural properties of these tracts to binocularly intact controls using standard diffusion indices. Results: Although both groups demonstrated asymmetries in indices in intrahemispheric tracts, monocular enucleation participants showed asymmetries opposite to control participants in the auditory and A1-V1 tracts. Monocularenucleation participants also demonstrated significantly lower fractional anisotropy in the audiovisual projections contralateral to the enucleated eye relative to control participants. Conclusions: Partial vision loss from early monocular enucleation results in altered structuralYork University Librarie
34745 US and EU sunscreens: A review of ultraviolet (UV) filters and safety data
A broad range of UV filters are available for use in sunscreen products. Knowledge of UV filters available both domestically and abroad remains important, since these products can be found in the online marketplace and may be included in future FDA monographs as a shift is made to an administrative order process. We reviewed the mechanism and safety data of all US and EU approved UV filters. Currently, there are 17 US FDA approved UV filters while the EU possesses an additional 16 UV filters. Of the US filters, 88.2% (15/17) are organic and 11.8% (2/17) are inorganic filters, with 35.3% (6/17) broad-spectrum, 52.9% (9/17) UVB only, and 11.8% (2/17) UVA only. Notably, 94.1% (16/17) have available human data. Of the EU exclusive filters, all (100%, 16/16) are organic filters. 50% (8/16) have human data while the remaining 50% (8/16) have data primarily related to physiochemical or toxicology profiles. Of these EU exclusive UV filters, 43.75% (7/16) are broad-spectrum, 50% (8/16) cover UVB only, and 6.25% (1/16) cover UVA only. Our review demonstrates that the EU possesses an exciting pool of novel UV filters with expanded options for coverage of all forms of UV radiation. Critically, the majority of sunscreens, both in the US and EU, have limited human data available due to prior limited requirements for such information. This information is likely forthcoming in the US as the FDA updates data requirement guidelines for sunscreens to be generally recognized as safe and effective
Deep Reinforcement Learning for Gas Trading
Deep Reinforcement Learning (Deep RL) has been explored for a number of
applications in finance and stock trading. In this paper, we present a
practical implementation of Deep RL for trading natural gas futures contracts.
The Sharpe Ratio obtained exceeds benchmarks given by trend following and mean
reversion strategies as well as results reported in literature. Moreover, we
propose a simple but effective ensemble learning scheme for trading, which
significantly improves performance through enhanced model stability and
robustness as well as lower turnover and hence lower transaction cost. We
discuss the resulting Deep RL strategy in terms of model explainability,
trading frequency and risk measures
TCAM-SSD: A Framework for Search-Based Computing in Solid-State Drives
As the amount of data produced in society continues to grow at an exponential
rate, modern applications are incurring significant performance and energy
penalties due to high data movement between the CPU and memory/storage. While
processing in main memory can alleviate these penalties, it is becoming
increasingly difficult to keep large datasets entirely in main memory. This has
led to a recent push for in-storage computation, where processing is performed
inside the storage device.
We propose TCAM-SSD, a new framework for search-based computation inside the
NAND flash memory arrays of a conventional solid-state drive (SSD), which
requires lightweight modifications to only the array periphery and firmware.
TCAM-SSD introduces a search manager and link table, which can logically
partition the NAND flash memory's contents into search-enabled regions and
standard storage regions. Together, these light firmware changes enable
TCAM-SSD to seamlessly handle block I/O operations, in addition to new search
operations, thereby reducing end-to-end execution time and total data movement.
We provide an NVMe-compatible interface that provides programmers with the
ability to dynamically allocate data on and make use of TCAM-SSD, allowing the
system to be leveraged by a wide variety of applications. We evaluate three
example use cases of TCAM-SSD to demonstrate its benefits. For transactional
databases, TCAM-SSD can mitigate the performance penalties for applications
with large datasets, achieving a 60.9% speedup over a conventional system that
retrieves data from the SSD and computes using the CPU. For database analytics,
TCAM-SSD provides an average speedup of 17.7x over a conventional system for a
collection of analytical queries. For graph analytics, we combine TCAM-SSD's
associative search with a sparse data structure, speeding up graph computing
for larger-than-memory datasets by 14.5%
Increase in b-wave amplitude after light stimulation of the blind spot is positively correlated with the axial length of myopic individuals
Altered retinal dopamine and ON-pathway activity may underlie myopia development. It has been shown that the stimulation of the blind spot with short-wavelength light increases the electroretinogram (ERG) b-wave amplitude of myopic eyes and may engage the retinal dopaminergic system. This study evaluated the impact of various durations of blind spot stimulation on the electrophysiological response of the myopic retina and their relationship to axial length. Six myopic individuals underwent three short-wavelength blue light blind spot stimulation protocols (10 s, 1 min, 10 min) using a virtual reality headset. As a control condition, no stimulation was shown for 1 min. The b-wave amplitude of the photopic full-field ERG was measured at baseline and 10, 20, 30, 40, 50, and 60 min after each condition. A significant increase in b-wave amplitude was observed for all stimulation protocols compared to the control. The peak b-wave amplitude was observed 20 min after the 1-min stimulation protocol and 60 min after the 10-min stimulation protocol. A significant positive correlation was found between axial length of the eye and percent change in b-wave amplitude for the 10-min stimulation protocol. A rapid and a delayed b-wave time course responses were observed following 1 min and 10 min of blind spot stimulation, respectively. Overall, these results indicate that light stimulation of the blind spot for various durations elevates ON-bipolar cell activity in the retina and as such is assumed to reduce the myopic response. These findings could have implications for future myopia treatment.This work was supported by the Federal Ministry of Education and Research, Industrie-in-Klinik-Plattform Program BMBF, Germany (FKZ: 13GW0256). This project was also supported by the Portuguese Foundation for Science and Technology (FCT) PTDC/FIS-OPT/0677/2014, the Strategic Funding UID/FIS/04650/2013 at Center of Physics, UMinho, and predoctoral grant SFRH/BD/136684/2018 to AAS
Behavioral deficits, early gliosis, dysmyelination and synaptic dysfunction in a mouse model of mucolipidosis IV
Mucolipidosis IV (MLIV) is caused by mutations in the gene MCOLN1. Patients with MLIV have severe neurologic deficits and very little is known about the brain pathology in this lysosomal disease. Using an accurate mouse model of mucolipidosis IV, we observed early behavioral deficits which were accompanied by activation of microglia and astrocytes. The glial activation that persisted during the course of disease was not accompanied by neuronal loss even at the late stage. In vivo [Ca2+]-imaging revealed no changes in resting [Ca2+] levels in Mcoln1−/− cortical neurons, implying their physiological health. Despite the absence of neuron loss, we observed alterations in synaptic plasticity, as indicated by elevated paired-pulse facilitation and enhanced long-term potentiation. Myelination deficits and severely dysmorphic corpus callosum were present early and resembled white matter pathology in mucolipidosis IV patients. These results indicate the early involvement of glia, and challenge the traditional view of mucolipidosis IV as an overtly neurodegenerative condition. Electronic supplementary material The online version of this article (doi:10.1186/s40478-014-0133-7) contains supplementary material, which is available to authorized users
"Mother-weights" and lost fathers: parents in South Asian American literature
That parent-child relationships should play a significant role within South Asian American literature is perhaps no surprise, since this is crucial material for any writer. But the particular forms they so often take – a dysfunctional mother-daughter dynamic, leading to the search for maternal surrogates; and the figure of the prematurely deceased father – are more perplexing. Why do families adhere to these patterns in so many South
Asian American texts and what does that tell us about this œuvre? More precisely, why are mothers subjected to a harsher critique than fathers and what purpose does this critique serve? How might we interpret the trope of the untimely paternal death? In this article I will seek to answer these questions – arguably key to an understanding of this growing body of writing – by considering works produced between the 1990s and the early twenty-first century by a range of South Asian American writers
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