Effective interactions in active Brownian suspensions

Active colloids exhibit persistent motion, which can lead to motility-induced phase separation (MIPS). However, there currently exists no microscopic theory to account for this phenomenon. We report a first-principles theory, free of fit parameters, for active spherical colloids, which shows explicitly how an effective many-body interaction potential is generated by activity and how this can rationalize MIPS. For a passively repulsive system the theory predicts phase separation and pair correlations in quantitative agreement with simulation. For an attractive system the theory shows that phase separation becomes suppressed by moderate activity, consistent with recent experiments and simulations, and suggests a mechanism for reentrant cluster formation at high activity

Hydrogen Two-Photon Continuum Emission from the Horseshoe Filament in NGC 1275

Far ultraviolet emission has been detected from a knot of Halpha emission in the Horseshoe filament, far out in the NGC 1275 nebula. The flux detected relative to the brightness of the Halpha line in the same spatial region is very close to that expected from Hydrogen two-photon continuum emission in the particle heating model of Ferland et al. (2009) if reddening internal to the filaments is taken into account. We find no need to invoke other sources of far ultraviolet emission such as hot stars or emission lines from CIV in intermediate temperature gas to explain these data.Comment: 9 pages, 8 figures. Accepted for publication in MNRA

Optical IFU Observations of the Brightest Cluster Galaxy NGC 4696: The Case for a Minor Merger and Shock-excited Filaments

We present deep optical integral-field spectroscopic observations of the nearby (z ~ 0.01) brightest cluster galaxy NGC 4696 in the core of the Centaurus Cluster, made with the Wide Field Spectrograph (WiFeS) on the ANU 2.3m telescope at Siding Spring Observatory. We investigate the morphology, kinematics, and excitation of the emission-line filaments and discuss these in the context of a model of a minor merger. We suggest that the emission-line filaments in this object have their origin in the accretion of a gas-rich galaxy and that they are excited by v ~100-200 km/s shocks driven into the cool filament gas by the ram pressure of the transonic passage of the merging system through the hot halo gas of NGC 4696.Comment: 19 pages, 15 figures, accepted for publication in The Astrophysical Journa

The UK Independence Party and the Politics of Englishness

The rise of the UK Independence Party has been one of the most dramatic and widely discussed features of British politics in recent years. This article argues that one vital but largely overlooked facet of this phenomenon has been the politics of national identity. It argues that despite the UK Independence Party’s ostensibly unionist stance, Englishness is an important pivot around which key elements of the party’s appeal revolve, notably in terms of its Euroscepticism, its opposition to immigration and its anti-establishment narrative. It argues that the Anglo-Britishness promulgated by the UK Independence Party allows space for the celebration of English identity rather more easily than of other sub-state national identities, as it does not challenge the legitimacy of the UK state, which is itself seen as the expression of Anglo-British identity and sovereignty. Scottish nationalism, on the other hand, is seen as a threat to the union and therefore anti-English

Exploring Older Adult Susceptibility to Fraudulent Computer Pop-Up Interruptions

© 2019, Springer International Publishing AG, part of Springer Nature. The proliferation of Internet connectivity and accessibility has been accompanied by an increase in cyber-threats, including fraudulent communications. Fake computer updates, which attempt to persuade people to download malicious software by mimicking trusted brands and/or instilling urgency, are one way in which fraudsters try to infiltrate systems. A recent study of young university students (M 18.52-years) found that when such pop-ups interrupt a demanding cognitive task, participants spent little time viewing them and were more likely to miss suspicious cues and accept these updates compared to when they were viewed without the pressure to resume a suspended task [1]. The aim of the current experiment was to test an older adult sample (N = 29, all >60 years) using the same paradigm. We predicted that they would be more susceptible to malevolent pop-ups [2]; trusting them more than younger adults (e.g., [3]), and would attempt to resume the interrupted task faster to limit forgetting of encoded items. Phase 1 involved serial recall memory trials interrupted by genuine, mimicked, and low authority pop-ups. During phase 2, participants rated messages with unlimited time and gave reasons for their decisions. It was found that more than 70% of mimicked and low authority pop-ups were accepted in Phase 1 vs ~80% genuine pop-ups (and these were all approximately 10% higher than [1]). This was likely due to a greater tendency to ignore or miss suspicious content when performing under pressure, despite spending longer with messages and reporting high awareness of scam techniques than younger adults. Older adult participants were more suspicious during Phase 2 performing comparably to the younger adults in [1]. Factors that may impact older adult decisions relating to fraudulent computer communications are discussed, as well as theoretical and practical implications

Aging Skin: Nourishing from the Inside Out, Effects of Good Versus Poor Nitrogen Intake on Skin Health and Healing

Skin is the outermost defense organ which protects us from the environment, constituting around 8 % of an adult’s body weight. Healthy skin contains one-eighth of the body’s total proteins. The balance of turnover and synthesis of skin proteins is primarily dependent on the availability of sufficient nitrogen-containing substrates, namely, amino acids, essential for protein metabolism in any other tissue and body organs. The turnover of skin proteins has been shown to be rapid, and the mobilization of amino acids at the expense of skin proteins is relevant in experimental models of protein malnutrition. As a result, alterations in nutritional status should be suspected, diagnosed, and eventually treated for any skin lesions. Protein malnutrition has a dramatic prevalence in patients aged >70 or more, independent of the reason for hospitalization. The quality of nutrition and content of essential amino acids are strictly connected to skin health and integrity of its protein components. Collagen fiber deposition is highly and rapidly influenced by alterations in the essential to nonessential amino acid ratios. The most relevant nutritional factor of skin health is the prevalence of essential amino acids

Exploring the usability of a connected autonomous vehicle human machine interface designed for older adults

Users of Level 4–5 connected autonomous vehicles (CAVs) should not need to intervene with the dynamic driving task or monitor the driving environment, as the system will handle all driving functions. CAV human-machine interface (HMI) dashboards for such CAVs should therefore offer features to support user situation awareness (SA) and provide additional functionality that would not be practical within non-autonomous vehicles. Though, the exact features and functions, as well as their usability, might differ depending on factors such as user needs and context of use. The current paper presents findings from a simulator trial conducted to test the usability of a prototype CAV HMI designed for older adults and/or individuals with sensory and/or physical impairments: populations that will benefit enormously from the mobility afforded by CAVs. The HMI was developed to suit needs and requirements of this demographic based upon an extensive review of HMI and HCI principles focused on accessibility, usability and functionality [1, 2], as well as studies with target users. Thirty-one 50-88-year-olds (M 67.52, three 50–59) participated in the study. They experienced four seven-minute simulated journeys, involving inner and outer urban settings with mixed speed-limits and were encouraged to explore the HMI during journeys and interact with features, including a real-time map display, vehicle status, emergency stop, and arrival time. Measures were taken pre-, during- and post- journeys. Key was the System Usability Scale [3] and measures of SA, task load, and trust in computers and automation. As predicted, SA decreased with journey experience and although cognitive load did not, there were consistent negative correlations. System usability was also related to trust in technology but not trust in automation or attitudes towards computers. Overall, the findings are important for those designing, developing and testing CAV HMIs for older adults and individuals with sensory and/or physical impairments