An Accelerated Multiboson Algorithm for Coulomb Gases with Dynamical Dielectric Effects

A recent reformulation [1] of the problem of Coulomb gases in the presence of a dynamical dielectric medium showed that finite temperature simulations of such systems can be accomplished on the basis of completely local Hamiltonians on a spatial lattice by including additional bosonic fields. For large systems, the Monte Carlo algorithm proposed in Ref. [1] becomes inefficient due to a low acceptance rate for particle moves in a fixed background multiboson field. We show here how this problem can be circumvented by use of a coupled particle-multiboson update procedure that improves acceptance rates on large lattices by orders of magnitude. The method is tested on a one-component plasma with neutral dielectric particles for a variety of system sizes.Comment: 13 pages, 2 figures, fixed typos, added reference

The clustering properties of the reddest galaxies with UKIDSS-DXS

Deep, photometric near-infrared surveys are the most effective ways to select massive galaxies at redshift $z>1$, where their characteristic spectral features are observed at wavelengths longer than optical surveys are designed to measure. In this Thesis, we present and study the clustering properties of such galaxies using the UKIDSS-DXS near-infrared survey. Firstly we produce deep, uniform mosaics for the $28{\rm deg^{2}}$ of $J$ and $K$ band imaging, which reach depths of $K_{\rm AB}\sim22.7$ ($5\sigma$ for point sources), and produce galaxy catalogues which we match with deep optical surveys. We demonstrate that these catalogues have reliable photometry (by way of comparison with 2MASS), we are able to efficiently remove foreground galactic stars, and that we produce the expected number counts galaxies. These catalogues will be made available at some point in the near future. From these catalogues we select Extremely Red Objects (EROs), Distant Red Galaxies (DRGs) and $BzK$s, all of which aim to exploit the strong $4000\text{\AA}$ break which is present in the oldest stellar populations. The combination of area and depth provided by DXS allows us to probe the large scale structure of the universe to tens of megaparsecs at $z>1$. We demonstrate using the small area of $H$-band DXS coverage that selection of EROs is still effective with similar criteria in $i-H$ and $r-H$, although do not suggest any new criteria different to those already existing in literature. We measure the angular two point correlation of the EROs and passive $BzK$ selection of galaxies. We show that these selections of galaxies exhibit significantly stronger clustering on the smallest scales than what is often assumed by the clustering studies of main sequence galaxies, indicating that these galaxies are residing in the most massive dark matter haloes. Further, we demonstrate that there is a strong break in the correlation function in these selections of galaxies. The correlation length $r_{0}$ we measure when considering the small scale (intra-halo) clustering alone is roughly constant for across the range of magnitudes DXS detects EROs, $K\sim18$ to $K\sim22$. Given that the halo mass of will be determined by the largest mass galaxy, we interpret this (in a qualitative sense) to mean that the dark matter host halo mass of the most massive EROs is roughly constant over the redshift range DXS measures EROs ($1<z<1.5$). A comparison of the angular correlation function for passive and star-forming $BzK$ galaxies (for three magnitude cuts where we have sufficient number counts) indicates that the passive galaxies are indeed much more strongly clustered than the star-forming: evidence of environmental quenching. We present $K$-band luminosity functions of our galaxy catalogues, and the ERO selection for $1<z<1.5$. We observe that the faint end slope of the ERO luminosity function is much steeper than those of the full galaxy catalogues, confirming that the ERO criteria selects galaxies that are amongst the most luminous in this redshift range. Finally, we measure the galaxy stellar mass function of the full sample of galaxies, and of restframe $U-B$ selected passive galaxies over the range $0.5<z<1.5$. We compute the integrated stellar mass density of the full galaxy sample, and our values match well with those in the literature. By computing the galaxy stellar mass density of the passive galaxy sample, and the contribution of the very massive end, we observe that the stellar mass density in the most massive passive galaxies is increasing faster than the stellar mass density of the passive galaxies as a whole, an observation which agrees with previous studies. Given that the galaxy stellar mass function of passive galaxies is well-described by a single Schechter function, which implies a single mechanism of galaxy quenching, we rule out a significant amount of dry mergers at the massive end, and instead postulate that this tentatively suggests that the mass quenching efficiency of the most massive galaxies is lower at later times. UKIDSS-DXS represents only a fraction of the vast datasets that the upcoming generation of instruments and surveys such as \textit{Rubin}-LSST, \textit{Euclid} and \textit{Roman} will produce, and this work is a precursor to investigations which use these surveys

Local Simulation Algorithms for Coulomb Gases with Dynamical Dielectric Effects

We discuss the application of the local lattice technique of Maggs and Rossetto to problems that involve the motion of objects with different dielectric constants than the background. In these systems the simulation method produces a spurious interaction force which causes the particles to move in an unphysical manner. We show that this term can be removed using a variant of a method known from high-energy physics simulations, the multiboson method, and demonstrate the effectiveness of this corrective method on a system of neutral particles. We then apply our method to a one-component plasma to show the effect of the spurious interaction term on a charged system.Comment: 13 pages, 4 figure

Older Peoples’ views of choice and decision-making in chronic kidney disease: a grounded theory study of access to the social world of renal care

Chronic kidney disease (CKD) is increasing in prevalence worldwide, with the largest increase occurring in individuals over the age of 65 years. Providing renal replacement therapy (RRT) to this older population will challenge health care systems, in terms of resources needed, as well as healthcare staff caring for this highly dependent group, who frequently have multiple co-morbidities. This study aimed to develop a theory that adequately accounts for the social processes involved when older people, with CKD stages 4 and 5 access treatment. The study sought to explore the concerns they had with CKD when making treatment decisions and identified how their concerns were resolved. This study employed grounded theory using the full complement of coding, categorisation, and theoretical development. Data was collected from interviews and observations of clinic consultations between patients and healthcare practitioners, from 21 older people who were at the point of making treatment decisions. The main concerns for older people in this study focused upon achieving safe care. This led to the development of the theory ‘Negotiating a Safe Existence’, which explains the processes older people encountered during their treatment decision-making journey. The basic social process of negotiation enabled them to use strategies and tactics to secure a place of safe care. This process involved transitioning through three stages represented by the sub-categories ‘Confronting a Deteriorating Self’, ‘Sourcing Information’, and ‘Traversing Disruption’. This grounded theory identified the importance of information to older people with differing awareness levels concerning the seriousness of their CKD. Varying degrees of negotiation were evident reflecting the differences in information awareness, their role in treatment decision-making, and their perceptions of risk and harm from dialysis. The theory represented an insight into the status passage of these individuals as they entered a critical phase of their CKD. The structural processes of the renal clinic, doctors, existing patients, and families all influenced older people’s status passage. The findings highlighted older people’s perception of self-care dialysis, with the majority of patients in this study employing risk-aversion strategies to ensure they received care in a place of perceived safety, which was mainly hospital based dialysis

‘I have more control over my life’:A qualitative exploration of challenges, opportunities, and support needs among autistic university students

Background Autistic people are known to experience more mental health issues than non-autistic people, and the same is true among university students. These difficulties can have long-term consequences, such as dropping out of university and unemployment. Understanding the challenges autistic students face can help institutions to better support this group, while allowing celebration of the opportunities higher education offers. Methods 12 autistic university students took part in semi-structured interviews about their mental health, the impact of university on their mental health, and their experiences of support while in higher education. Interviews were subject to thematic analysis. Results Three key themes were identified from autistic student accounts: Relationships, Independence, and Support. While each of these encompassed positive and negative elements, Relationships were described as tying everything together – when these were supportive, things went well, but when they were characterized by stigmatizing attitudes, students experienced much greater difficulties at university. Conclusions Autistic students can and do thrive at university, as shown by many of our participants. However, all faced significant challenges with their mental health at times, and experienced varying levels of support. Improving autism knowledge among staff, with emphasis on enabling better relationships, would make a significant difference to the autistic student experience

SEALED WITH A KISS: HEAD-TURNING ASYMMETRIES DURING KISSING ARE MODULATED BY CONTEXT AND INFLUENCE PERCEPTUAL JUDGEMENTS

When leaning forward to kiss a romantic partner, individuals tend to direct their kiss to the right more often than to the left. The theoretical mechanism guiding this asymmetry is that it originates from a right head-turning preference observed within early stages of human development. By contrast, other lateral turning biases are theorized to stem from differences of hemispheric specialization of emotion rather than from an innate influence, to which the lateral direction of these biases are dependent on their situational context. My first two studies examine if the context for non-romantic conventions of lip-kissing convey a comparable right-turn bias, as the existing literature has focused on romantic-kissing gestures. If kissing laterality is caused from an innately guided right head-turning bias, this directionality should transcend different forms of kissing. Study 1 analysed the turning directions of kisses from videos from the First Kiss social media trend, featuring strangers performing a lip-to-lip kiss. The predominant right-turn bias was not supported; rather, no significant directional bias was observed. To further explore the role of a non-romantic kissing context, study 2 introduced the type of kiss shared between a parent and child. Images of parent-parent kissing (romantic context) and parent-child kissing (parental context) couples were collected for an archival analysis. A right-turn kissing bias was revealed, but only for the romantic kissing couples; for parental kisses, a leftward bias was found. Collectively, the first two studies do not coincide with the congenital account of kissing laterality, as attenuated and reversed turning biases were found. For study 3, romantic and parental kissing were further investigated while also exploring if perceptual input of kissing biases corresponds to the direction of motor output. Studies 3a and 3b employed a forced-choice task in which image-pairs of romantic and parental kissing couples were presented and asked which image was perceived as more “passionate” and “loving”, respectively. Kisses between romantic couples were perceived to be more passionate when displaying a right turn in comparison to a left turn, whereas images with neither left nor right turns were perceived to be more loving for parent-child kissing couples. The final study examines how cognitive evaluations unrelated to the kiss are influenced in the field of advertising. Original and mirror-reversed versions of advertisements with models kissing were displayed in a forced-choice preference task and consumer-judgement task. Models illustrating a right turn (vs left turn) when kissing were preferred when identical images were presented. When ads were presented individually, right-turn (vs left-turn) kisses resulted in higher consumer attitudes and purchase intention. This body of research challenges the previous rationale that kissing laterality persists from the right head-turning preference observed in infancy, as contexts with parental and strangers kissing reveal a leftward preference or no directional bias. Our findings also contribute to our understanding of how kissing biases are exhibited within earlier stages of cognitive processing, such that perceptions of passion and consumer preferences for visual stimuli displaying romantic kissing corresponds to the direction of authentic turning behaviour: the right. Further discussion speculates on how cerebral lateralization of emotions may contribute to kissing laterality, to which a variety of future directions are suggested to test these predictions