The Effect of Subgrid Physics Models on the Pattern Speed of Bars in Cosmological Simulations

The amount of dark matter in the central region of galaxies is intimately linked to the slowdown of galactic bars. Recent work has revealed a tension between bars that are observed in the local universe and those produced in cosmological hydrodynamical simulations at z = 0. Observed bars are found to be `fast', i.e. to have a small ratio between the corotation radius and bar length, while those in the simulations are `slow', i.e. the corotation radius much larger than the bar length. Recent work has been carried out in an attempt to find the root cause of this discrepancy, and indeed to explore whether fast bars can exist within a $\Lambda$CDM universe. The ratio of stars to dark matter, along with other properties such as gas fraction and velocity dispersion, has been linked to the evolution of bars. The resolution of simulations is often cited as the underlying cause of differences between simulations. In this work, I explore the slowdown of bars in two sets of cosmological zoom-in simulations which are identical, apart from their galaxy formation model (i.e. the subgrid physics). I then study how the slowdown of bars in these two models is related to parameters such as the stellar-to-dark matter ratio, the gas fraction and velocity dispersion, all of which are determined by the subgrid physics itself. Using halos from the Auriga suite of zoom-in cosmological simulations, I rerun them with the subgrid physics model from IllustrisTNG. I find that the bars in Auriga are faster than those run with the TNG model, i.e. Auriga have a smaller ratio of the corotation radius to bar length. The bars in TNG are shorter and stronger than in the Auriga model. In terms of global halo properties, Auriga galaxies have a greater stellar mass in their disc, are more baryon dominated at 30kpc, have a greater gas fraction in the disc. They also have a lower stellar velocity dispersion within a disc of radius 6kpc and height 1kpc from the centre. All of these differences lead to the conclusion that the subgrid physics model has a profound effect on the overall properties of a galaxy, include the speed of the bar. We therefore show that the changes in subgrid physics can have a significant effect on the dynamical properties of barred spiral galaxies and, as such, the dynamical properties of bars can be used to constrain models of galaxy formation and evolution

Gravitational Stability of Vortices in Bose-Einstein Condensate Dark Matter

We investigate a simple model for a galactic halo under the assumption that it is dominated by a dark matter component in the form of a Bose-Einstein condensate involving an ultra-light scalar particle. In particular we discuss the possibility if the dark matter is in superfluid state then a rotating galactic halo might contain quantised vortices which would be low-energy analogues of cosmic strings. Using known solutions for the density profiles of such vortices we compute the self-gravitational interactions in such halos and place bounds on the parameters describing such models, such as the mass of the particles involved.Comment: 17 pages, 4 figures, submitted to CQ

Inequality talk:How discourses by senior men reinforce exclusions from creative occupations

Cultural Studies has drawn attention to the way that cultural and creative industries are marked by significant inequalities. This article explores how these inequalities are maintained, through fieldwork with senior men making decisions in cultural and creative industries. Drawing on 32 interviews with senior men across a range of cultural and creative industry occupations, conducted as part of a larger (N = 237) project, the analysis shows that misrecognition and outright rejection of inequalities are now not the norm. Rather, ‘inequality talk’ and the recognition of structural barriers for marginalised groups is a dominant discourse. However, individual careers are still explained by gentlemanly tropes and the idea of luck, rather than by reference to structural inequalities. The distance between the discourse of career luck and ‘inequality talk’ helps to explain the persistence of exclusions from the workforce for those who are not white, middle class origin, men. This has important implications for inequalities in cultural production and consumption, and in turn for wider social inequality

Social mobility and ‘openness’ in creative occupations since the 1970s

Social mobility in the cultural sector is currently an important issue in government policy and public discussion, associated with perceptions of a collapse in numbers of working-class origin individuals becoming artists, actors, musicians and authors. The question of who works in creative occupations has also attracted significant sociological attention. To date, however, there have been no empirically grounded studies into the changing social composition of such occupations. This article uses the Office for National Statistics Longitudinal Study to show that, while those from more privileged social backgrounds have long dominated, there has been no change in the relative class mobility chances of gaining access to creative work. Instead, we must turn to the pattern of absolute mobility into this sector in order to understand claims that it is experiencing a ‘mobility crisis’

Cosmology meets condensed matter

This thesis is concerned with the interface of cosmology and condensed matter. Although at either end of the scale spectrum, the two disciplines have more in common than one might think. Condensed matter theorists and high-energy field theorists study, usually independently, phenomena embedded in the structure of a quantum field theory. It would appear at first glance that these phenomena are disjoint, and this has often led to the two fields developing their own procedures and strategies, and adopting their own nomenclature. We will look at some concepts that have helped bridge the gap between the two subjects, enabling progress in both, before incorporating condensed matter techniques to our own cosmological model. By considering ideas from cosmological high-energy field theory, we then critically examine other models of astrophysical condensed matter phenomena. In Chapter 1, we introduce the current cosmological paradigm, and present a somewhat historical overview of the interplay between cosmology and condensed matter. Many concepts are introduced here that later chapters will follow up on, and we give some examples in which condensed matter physics has had a very real effect on informing cosmology. We also reflect on the most recent incarnations of the condensed matter / cosmology interplay, and the future of these developments. Chapter 2 presents the Einstein-Klein-Gordon system of equations and their non-relativistic and nonlinear counterparts, the Schrodinger-Poisson, and nonlinear Schrodinger (Gross Pitaevskii)-Poisson systems. We give a more technical overview of the various applications of these systems of equations, as well as discussing the role and interpretation of condensates in the field of cosmology. In Chapter 3 we discuss more qualitatively the fluid-mechanical methods used in a wave-mechanical approach to structure formation, and in formulations of condensed matter models. Taking a lead from the condensed matter side, we look at some of the details of the Gross-Pitaevskii equation, particularly with regard to quantum vortices, and then put this quantum-mechanical system into a cosmological environment by coupling it to the Poisson equation, in an effort to pin down some of the parameters that may be consistent with the existence of vortices in a cosmological Bose-Einstein condensate. In Chapter 4 we turn to high-energy field theory and elucidate further some of the relationships with condensed matter physics that are present. We also critically examine a Bose-Einstein dark matter model in light of these considerations. Chapter 5 rounds off with a discussion and suggestions for further work based upon models we have discussed, as well as some ideas for models that have not yet been mentioned. An appendix discusses techniques for moving from the relativistic Einstein-Klein-Gordon equations to the Schrodinger-Poisson system

Art for the many not the few : addressing cultural & other inequalities at scale

There is currently keen interest in the social inequalities in the creative economy. Publicly funded arts organisations are seeking new ways of engaging with communities to ensure art can be for the many and not the few. While the UK City of Culture programme, similar cultural mega-events rooted within place, and priority area funding programmes from Arts Council England have reduced spatial inequalities, they do not seek to reduce social inequalities as a priority. However, social and spatial inequalities are intrinsically linked, something that. Coventry UK CoC 2021 was unique in recognising when it put hyper-local co-creation front and centre. By focusing on hyper-local offerings, the programme offered local proximity, (important to people who do not often engage with culture or who are in lower economic groups,) and the potential for a sense of ownership by the kinds of people who are most often missing from cultural spaces

Effect of methamphetamine dependence on inhibitory deficits in a novel human open-field paradigm.

RationaleMethamphetamine (MA) is an addictive psychostimulant associated with neurocognitive impairment, including inhibitory deficits characterized by a reduced ability to control responses to stimuli. While various domains of inhibition such as exaggerated novelty seeking and perseveration have been assessed in rodents by quantifying activity in open-field tests, similar models have not been utilized in human substance abusers. We recently developed a cross-species translational human open-field paradigm, the human behavior pattern monitor (hBPM), consisting of an unfamiliar room containing novel and engaging objects. Previous work demonstrated that manic bipolar subjects exhibit a disinhibited pattern of behavior in the hBPM characterized by increased object interactions.ObjectivesIn the current study, we examined the effect of MA dependence on inhibitory deficits using this paradigm. hBPM activity and object interactions were quantified in 16 abstinent MA-dependent individuals and 18 matched drug-free comparison subjects. The Wisconsin card sorting task (WCST) and the positive and negative syndrome scale (PANSS) were administered to assess executive function and psychopathology.ResultsMA-dependent participants exhibited a significant increase in total object interactions, time spent with objects, and perseverative object interactions relative to comparison subjects. Greater object interaction was associated with impaired performance on the WCST, higher PANSS scores, and more frequent MA use in the past year.ConclusionsAbstinent MA-dependent individuals exhibited impaired inhibition in the hBPM, displaying increased interaction with novel stimuli. Utilization of this measure may enable assessment of inhibitory deficits relevant to drug-seeking behavior and facilitate development of intervention methods to reduce high-risk conduct in this population

Cosmology meets condensed matter

This thesis is concerned with the interface of cosmology and condensed matter. Although at either end of the scale spectrum, the two disciplines have more in common than one might think. Condensed matter theorists and high-energy field theorists study, usually independently, phenomena embedded in the structure of a quantum field theory. It would appear at first glance that these phenomena are disjoint, and this has often led to the two fields developing their own procedures and strategies, and adopting their own nomenclature. We will look at some concepts that have helped bridge the gap between the two subjects, enabling progress in both, before incorporating condensed matter techniques to our own cosmological model. By considering ideas from cosmological high-energy field theory, we then critically examine other models of astrophysical condensed matter phenomena. In Chapter 1, we introduce the current cosmological paradigm, and present a somewhat historical overview of the interplay between cosmology and condensed matter. Many concepts are introduced here that later chapters will follow up on, and we give some examples in which condensed matter physics has had a very real effect on informing cosmology. We also reflect on the most recent incarnations of the condensed matter / cosmology interplay, and the future of these developments. Chapter 2 presents the Einstein-Klein-Gordon system of equations and their non-relativistic and nonlinear counterparts, the Schrodinger-Poisson, and nonlinear Schrodinger (Gross Pitaevskii)-Poisson systems. We give a more technical overview of the various applications of these systems of equations, as well as discussing the role and interpretation of condensates in the field of cosmology. In Chapter 3 we discuss more qualitatively the fluid-mechanical methods used in a wave-mechanical approach to structure formation, and in formulations of condensed matter models. Taking a lead from the condensed matter side, we look at some of the details of the Gross-Pitaevskii equation, particularly with regard to quantum vortices, and then put this quantum-mechanical system into a cosmological environment by coupling it to the Poisson equation, in an effort to pin down some of the parameters that may be consistent with the existence of vortices in a cosmological Bose-Einstein condensate. In Chapter 4 we turn to high-energy field theory and elucidate further some of the relationships with condensed matter physics that are present. We also critically examine a Bose-Einstein dark matter model in light of these considerations. Chapter 5 rounds off with a discussion and suggestions for further work based upon models we have discussed, as well as some ideas for models that have not yet been mentioned. An appendix discusses techniques for moving from the relativistic Einstein-Klein-Gordon equations to the Schrodinger-Poisson system

Dedicated Shift Wrap-up Time Does Not Improve Resident Sign-out Volume or Efficiency

Objectives: Sign-out (SO) is a challenge to the emergency physician. Some training programs have instituted overlapping 9-hour shifts. The residents see patients for eight hours, and have one hour of wrap-up time. This hour helps them complete patient care, leaving fewer patients to sign-out. We examined whether this strategy impacts SO burden.Methods: This is a retrospective review of patients evaluated by emergency medicine (EM) residents working 9-hour (eight hours of patient care, one hour wrap-up time) and 12-hour shifts (12 hours patient care, no reserved time for wrap-up). Data were collected by reviewing the clinical tracker. A patient was assigned to the resident who initiated care and dictated the chart. SO was defined as any patient in the ED without disposition at change of shift. Patient turn-around-time (TAT) was also recorded.Results: One-hundred sixty-one postgraduate-year-one resident (PGY1), 264 postgraduate-year-two resident (PGY2), and 193 postgraduate-year-three resident (PGY3) shifts were included. PGY1s signed out 1.9 patients per 12-hour shift. PGY2s signed out 2.3 patients on 12-hour shifts and 1.8 patients on 9-hour shifts. PGY3s signed out 2.1 patients on 12-hour shifts and 2.0 patients on 9-hour shifts. When we controlled for patients seen per hour, SO burden was constant by class regardless of shift length, with PGY2s signing out 18% of patients seen compared to 15% for PGY3s. PGY1s signed out 18% of patients seen. TAT for patients seen by PGY1s and PGY2s was similar, at 189 and 187 minutes, respectively. TAT for patients seen by PGY3s was significantly less at 175 minutes.Conclusion: The additional hour devoted to wrapping up patients in the ED had no affect on SO burden. The SO burden represented a fixed percentage of the total number of patients seen by the residents. PGY3s sign-out a smaller percentage of patients seen compared to other classes, and have faster TATs. [West J Emerg Med. 2010; 11(1):35-39]