159 research outputs found
An internal characterisation of radiality
In this paper, we will investigate how radiality occurs in topological spaces
by considering neighbourhood bases generated by nests. We will define a new
subclass of radial spaces, called the independently-based spaces, that contains
LOTS, GO-spaces and spaces with well-ordered neighbourhood bases. We show that
first-countable spaces are precisely the independently-based, strongly
Fr\'echet spaces and we give an example of a Fr\'echet-Urysohn space that is
neither independently-based nor strongly Fr\'echet.Comment: 11 pages. Changelog: cleaned up LaTeX source and fixed
'folgenbestimmt' typo (thanks to Thilo Weinart for spotting this!
Optimal control of two qubits via a single cavity drive in circuit quantum electrodynamics
Optimization of the fidelity of control operations is of critical importance
in the pursuit of fault-tolerant quantum computation. We apply optimal control
techniques to demonstrate that a single drive via the cavity in circuit quantum
electrodynamics can implement a high-fidelity two-qubit all-microwave gate that
directly entangles the qubits via the mutual qubit-cavity couplings. This is
performed by driving at one of the qubits' frequencies which generates a
conditional two-qubit gate, but will also generate other spurious interactions.
These optimal control techniques are used to find pulse shapes that can perform
this two-qubit gate with high fidelity, robust against errors in the system
parameters. The simulations were all performed using experimentally relevant
parameters and constraints.Comment: Final published versio
Towards a dephasing diode: asymmetric and geometric dephasing
We study the effect of a noisy environment on spin and charge transport in
ballistic quantum wires with spin-orbit coupling (Rashba coupling). We find
that the wire then acts as a ``dephasing diode'', inducing very different
dephasing of the spins of right and left movers. We also show how Berry phase
(geometric phase) in a curved wire can induce such asymmetric dephasing, in
addition to purely geometric dephasing. We propose ways to measure these
effects through spin detectors, spin-echo techniques, and Aharanov-Bohm
interferometry.Comment: 4 pages (2 fig) v2: extensive improvements to "readability" &
references adde
A scoping investigation of eye-tracking in Electronic Gambling Machine (EGM) play
The nature of the association between Electronic Gambling Machines (EGMs) and gambling problems remains uncertain. Eye-tracking offers a potentially powerful method to understand how individuals attend to the visual displays and features of machine games as a function of machine experience, use of other commercial gambling products, the degree to which some game features capture players attention and, critically, vulnerability to problematic patterns of machine play. Characterizing machine players' attention to machine games may aid the design of harm-minimization measures such as, but not limited to, pop-up messages and visible clocks; and provide an important ancillary measure for testing their efficacy. Here, we conducted the first study to use eye-tracking to improve our understanding of how machine players attend to EGM displays in local bookmaker offices (LBOs) situated across North West England, as well as North East and North Wales. Through liaison with 4 bookmaker operators, we recruited a sample of 118 LBO customers who, first, completed a small number of questionnaires about their gambling history and other gambling activities and, then, completed a typical machine gambling session with their own money while wearing eye-tracking glasses to capture eye-movement pattern. The protocol captured regions of gaze fixation while playing (B2) roulette or (B3) slots on B category machines (Gambling Commission, 2012). The final dataset consisted of 91 eye-tracking recordings: 59 games of roulette and 57 slots games. Our principle dependent measure was the percentage of fixations of visual features and machine display locations (as areas of interest; AOIs) as an objective indicator of overt visual attention and their importance to machine players. Our data analysis included statistical correction for differences in the relative size (display area) and display duration across AOIs. To summarise, our main findings are as follows: In roulette, 56.3% of LBO machine players fixations were distributed over the chip-placement area while placing bets (in the stationary states of the game), rising to 75.1% while the roulette wheel Eye-tracking & machines Rogers & Leek; main text v2; 24th March 2017 3 spun in the moving states of the games). Machine players looked at their credit balance 7.2% of the time while placing bets, only slightly more frequently than the previous winning number at 6.8%. In slots games, the slot-reels dominated machine players' visual attention: accounting for 53.6% of fixations while placing bets, rising to 91.7% while spinning. Players' fixations of their credit-balances amounted to 14% of the total while placing bets but only 5.1% while the slot-reels spun. Fixations away from the machine were more frequent while placing bets in both roulette and slots games: 13.5% and 13.4% respectively, dropping to 2.4% and 1.1% while the wheel/slot-reels spun. Players' age and years of education were only weakly related to fixation patterns while playing roulette or slots games. Unemployed players allocated fewer fixations over the chip-placement area (both while the roulette wheel was stationary and while it spun) and over the slot-reels while placing bets; they also tended to look away from the machine more while placing bets in roulette. Frequent machine players tended to look at the roulette wheel less frequently than infrequent users while playing roulette games; involvement in other forms of gambling tended to increase attention towards credit balance but was not otherwise linked to particular patterns of fixations. Finally, problems gamblers allocated fewer fixations to the roulette wheel while placing bets and while it spun compared to non-problem gamblers; and tended to look away from the machine more frequently; in slots games, problem gamblers looked more frequently at amount-won messages. These data describe, for the first time, the distributions of machine players overt attention while navigating roulette and slots games in a commercial settings. In general, fixation counts showed the least variability for moving visual features and events that are likely to capture attention automatically, such as spinning Eye-tracking & machines Rogers & Leek; main text v2; 24th March 2017 4 roulette wheels or spinning slot-reels. However, fixations were also concentrated upon visual features and elements with relatively less attentional capture such as the chip-placement-area while placing bets in roulette and looking at credit balances in both games. Associations between patterns of fixation and both frequency of past-month expenditure on B category machines and broader gambling involvement were modest, suggesting that most of the variability in eye-movements and fixations reflects players navigation through the sequenced behaviours of placing bets and monitoring spinning roulette wheels or slot-reels in anticipation of game outcomes. Players with extensive machine experience tended to discount slightly the roulette wheel as a visual feature; while players with broader patterns of gambling activity looked at credit balances frequently, suggesting that such individuals are mindful of available credits. Players with gambling problems allocated fewer fixations over the chip-placement-area while placing bets and while watching the wheel spun compared to non-problem gamblers, suggesting that placing of bets can be accomplished with less attentional focus. These individuals were also more likely to look away from the machine altogether, suggesting that, in roulette play, gambling problems might be associated with a loosened attentional focus to events elsewhere in the shop. However, in slots games, problems gamblers' attended to the reward signals of previous games (amount-won) when placing the next bets. So far as we are aware, these data are the first to show that eye-tracking methodology has some potential to offer insights into machine-player interactions, and to provide a bias-free measure of individual differences in attention to games visual features and events as a function of their experience with gambling machines, gambling background and vulnerability to gambling-related harms. This study offers a methodology for studying and optimizing the timing, placement and content of harm-minimization messaging
Study protocol for a randomised pilot study of a computer-based, non-pharmacological cognitive intervention for motor slowing and motor fatigue in Parkinson’s disease
A scoping investigation of eye-tracking in Electronic Gambling Machine (EGM) play
The nature of the association between Electronic Gambling Machines (EGMs) and gambling problems remains uncertain. Eye-tracking offers a potentially powerful method to understand how individuals attend to the visual displays and features of machine games as a function of machine experience, use of other commercial gambling products, the degree to which some game features capture players attention and, critically, vulnerability to problematic patterns of machine play. Characterizing machine players' attention to machine games may aid the design of harm-minimization measures such as, but not limited to, pop-up messages and visible clocks; and provide an important ancillary measure for testing their efficacy. Here, we conducted the first study to use eye-tracking to improve our understanding of how machine players attend to EGM displays in local bookmaker offices (LBOs) situated across North West England, as well as North East and North Wales. Through liaison with 4 bookmaker operators, we recruited a sample of 118 LBO customers who, first, completed a small number of questionnaires about their gambling history and other gambling activities and, then, completed a typical machine gambling session with their own money while wearing eye-tracking glasses to capture eye-movement pattern. The protocol captured regions of gaze fixation while playing (B2) roulette or (B3) slots on B category machines (Gambling Commission, 2012). The final dataset consisted of 91 eye-tracking recordings: 59 games of roulette and 57 slots games. Our principle dependent measure was the percentage of fixations of visual features and machine display locations (as areas of interest; AOIs) as an objective indicator of overt visual attention and their importance to machine players. Our data analysis included statistical correction for differences in the relative size (display area) and display duration across AOIs. To summarise, our main findings are as follows: In roulette, 56.3% of LBO machine players fixations were distributed over the chip-placement area while placing bets (in the stationary states of the game), rising to 75.1% while the roulette wheel Eye-tracking & machines Rogers & Leek; main text v2; 24th March 2017 3 spun in the moving states of the games). Machine players looked at their credit balance 7.2% of the time while placing bets, only slightly more frequently than the previous winning number at 6.8%. In slots games, the slot-reels dominated machine players' visual attention: accounting for 53.6% of fixations while placing bets, rising to 91.7% while spinning. Players' fixations of their credit-balances amounted to 14% of the total while placing bets but only 5.1% while the slot-reels spun. Fixations away from the machine were more frequent while placing bets in both roulette and slots games: 13.5% and 13.4% respectively, dropping to 2.4% and 1.1% while the wheel/slot-reels spun. Players' age and years of education were only weakly related to fixation patterns while playing roulette or slots games. Unemployed players allocated fewer fixations over the chip-placement area (both while the roulette wheel was stationary and while it spun) and over the slot-reels while placing bets; they also tended to look away from the machine more while placing bets in roulette. Frequent machine players tended to look at the roulette wheel less frequently than infrequent users while playing roulette games; involvement in other forms of gambling tended to increase attention towards credit balance but was not otherwise linked to particular patterns of fixations. Finally, problems gamblers allocated fewer fixations to the roulette wheel while placing bets and while it spun compared to non-problem gamblers; and tended to look away from the machine more frequently; in slots games, problem gamblers looked more frequently at amount-won messages. These data describe, for the first time, the distributions of machine players overt attention while navigating roulette and slots games in a commercial settings. In general, fixation counts showed the least variability for moving visual features and events that are likely to capture attention automatically, such as spinning Eye-tracking & machines Rogers & Leek; main text v2; 24th March 2017 4 roulette wheels or spinning slot-reels. However, fixations were also concentrated upon visual features and elements with relatively less attentional capture such as the chip-placement-area while placing bets in roulette and looking at credit balances in both games. Associations between patterns of fixation and both frequency of past-month expenditure on B category machines and broader gambling involvement were modest, suggesting that most of the variability in eye-movements and fixations reflects players navigation through the sequenced behaviours of placing bets and monitoring spinning roulette wheels or slot-reels in anticipation of game outcomes. Players with extensive machine experience tended to discount slightly the roulette wheel as a visual feature; while players with broader patterns of gambling activity looked at credit balances frequently, suggesting that such individuals are mindful of available credits. Players with gambling problems allocated fewer fixations over the chip-placement-area while placing bets and while watching the wheel spun compared to non-problem gamblers, suggesting that placing of bets can be accomplished with less attentional focus. These individuals were also more likely to look away from the machine altogether, suggesting that, in roulette play, gambling problems might be associated with a loosened attentional focus to events elsewhere in the shop. However, in slots games, problems gamblers' attended to the reward signals of previous games (amount-won) when placing the next bets. So far as we are aware, these data are the first to show that eye-tracking methodology has some potential to offer insights into machine-player interactions, and to provide a bias-free measure of individual differences in attention to games visual features and events as a function of their experience with gambling machines, gambling background and vulnerability to gambling-related harms. This study offers a methodology for studying and optimizing the timing, placement and content of harm-minimization messaging
Moon jam: enhancing welfare for nocturnal species
This workshop will use a zoo jam methodology to explore how technology can support the design and management of systems that enhance visitor experiences while supporting the enrichment and welfare of nocturnal species. Animals that are active in the dark can sometimes be overlooked by humans, simply because we do not perceive them, or we are not being active ourselves. During the event, participants will collaborate to address a series of workshop-themed briefs provided by animal experts from zoos and conservation organisations, with the aim of designing technology-enhanced solutions to the challenges expressed
Direct integration of intensity-level data from Affymetrix and Illumina microarrays improves statistical power for robust reanalysis
<p>Abstract</p> <p>Background</p> <p>Affymetrix GeneChips and Illumina BeadArrays are the most widely used commercial single channel gene expression microarrays. Public data repositories are an extremely valuable resource, providing array-derived gene expression measurements from many thousands of experiments. Unfortunately many of these studies are underpowered and it is desirable to improve power by combining data from more than one study; we sought to determine whether platform-specific bias precludes direct integration of probe intensity signals for combined reanalysis.</p> <p>Results</p> <p>Using Affymetrix and Illumina data from the microarray quality control project, from our own clinical samples, and from additional publicly available datasets we evaluated several approaches to directly integrate intensity level expression data from the two platforms. After mapping probe sequences to Ensembl genes we demonstrate that, ComBat and cross platform normalisation (XPN), significantly outperform mean-centering and distance-weighted discrimination (DWD) in terms of minimising inter-platform variance. In particular we observed that DWD, a popular method used in a number of previous studies, removed systematic bias at the expense of genuine biological variability, potentially reducing legitimate biological differences from integrated datasets.</p> <p>Conclusion</p> <p>Normalised and batch-corrected intensity-level data from Affymetrix and Illumina microarrays can be directly combined to generate biologically meaningful results with improved statistical power for robust, integrated reanalysis.</p
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