Correlated Spectral and Recurrence Variations of Cygnus X-1

We present results of recurrence analysis of the black hole X-ray binary Cygnus X-1 using combined observations from the Rossi X-ray Timing Explorer All-sky Monitor and the Japanese Monitor of All-sky X-ray Image aboard the ISS. From the time-dependent windowed recurrence plot (RP), we compute ten recurrence quantities that describe the dynamical behavior of the source and compare them to the spectral state at each point in time. We identify epochs of state changes corresponding to transitions into highly deterministic or highly stochastic dynamical regimes and their correlation to specific spectral states. We compare k-Nearest Neighbors and Random Forest models for various sizes of the time-dependent RP. The spectral state in Cygnus X-1 can be predicted with greater than 95 per cent accuracy for both types of models explored across a range of RP sizes based solely on the recurrence properties. The primary features from the RP that distinguish between spectral states are the determinism, Shannon entropy, and average line length, all of which are systematically higher in the hard state compared to the soft state. Our results suggest that the hard and soft states of Cygnus X-1 exhibit distinct dynamical variability and the time domain alone can be used for spectral state classification.Comment: 17 pages, 10 figures, 7 tables; Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Investigating Non-linear and Stochastic Hard X-ray Variability of Active Galactic Nuclei using Recurrence Analysis

We present results of recurrence analysis of 46 active galactic nuclei (AGN) using light curves from the 157-month catalog of the Swift Burst Alert Telescope (BAT) in the 14-150 keV band. We generate recurrence plots and compute recurrence plot metrics for each object. We use the surrogate data method to compare all derived recurrence-based quantities to three sets of stochastic light curves with identical power spectrum, flux distribution, or both, in order to determine the presence of determinism, non-linearity, entropy, and non-stationarity. We compare these quantities with known physical characteristics of each system, such as black hole mass, Eddington ratio, and bolometric luminosity, radio loudness, obscuration, and spectroscopic type. We find that almost all AGN in this sample exhibit substantial higher-order modes of variability than is contained in the power spectrum, with approximately half exhibiting nonlinear or non-stationary behavior. We find that Type 2 AGN are more likely to contain deterministic variability than Type 1 AGN while the same distinction is not found between obscured and unobscured AGN. The complexity of variability among Type 1 AGN is anticorrelated with Eddington ratio, while no relationship is found among Type 2 AGN. The connections between the recurrence properties and AGN class suggest that hard X-ray emission is a probe of distinct accretion processes among classes of AGN, which supports interpretations of changing-look AGN and challenges the traditional unification model that classifies AGN only on viewing angle.Comment: 20 pages, 4 figures, 13 table

Outside interference or Hong Kong embracing its unique identity? : The Chinese Universities Shakespeare Festival

Ongoing clashes between Hong Kong citizens and its government have foregrounded questions about outside interference in Hong Kong’s politics (largely from the government and media of People’s Public of China), as well as debate about what institutions in Hong Kong are neo-colonial, heavily inflected with nostalgia for British colonialism, or in the process of being ‘colonised’ by the People’s Republic of China. This article looks at Shakespeare in Hong Kong (and, to some extent, greater Chinese) theatre and education as one of those contested institutions, using the particular case of the now-defunct Chinese Universities Shakespeare Festival. The author probes their initial, surface impression of the festival as a simple outpouring of colonial sentiment and impulse, using its sizeable archives to realise a reading of the institution that highlights the complexities of international and intra-regional politics, culture and identity in Hong Kong and greater China. It builds on the Hong Kong literary critic Michael Ingham’s call for attention to Hong Kong’s quest – sometimes overt (as in the demonstrations of 2019), sometimes implicit (in the body of literature Ingham explores in his cultural and literary history) – for a unique, post-colonial identity that is inspired – but, critically, not confined – by its Chinese and British histories. The article briefly outlines the origins and set-up of the festival before juxtaposing the dominance of English language and culture in it with the opportunities it presents (seized by several teams) for intra-regional cooperation, competition and sharing diverse, greater Chinese cultures. The article offers a model for critically appraising other institutions and cultural products in Hong Kong in ways that resist easy binaries of British or Chinese, colonial or indigenous

The victorious English language: hegemonic practices in the management academy

This study explores hegemonic linguistic processes, that is, the dominant and unreflective use of the English language in the production of textual knowledge accounts. The authors see the production of management knowledge as situated in central or peripheral locations, which they examine from an English language perspective. Their inquiry is based on an empirical study based on the perspectives of 33 management academics (not English language speakers) in (semi) peripheral locations, who have to generate and disseminate knowledge in and through the English language. Although the hegemony of the center in the knowledge production process has long been acknowledged, the specific contribution of this study is to explore how the English language operates as part of the “ideological complex” that produces and maintains this hegemony, as well as how this hegemony is manifested at the local level of publication practices in peripherally located business and management schools

Forward with Dementia: process evaluation of an Australian campaign to improve post-diagnostic support

Background: Forward with Dementia is a co-designed campaign to improve communication of dementia diagnosis and post-diagnostic support. Methods: Webinars, a website, social and traditional media, and promotions through project partners were used to disseminate campaign messages to health and social care professionals (primary audience) and people with dementia and carers (secondary audience). The campaign ran between October 2021 and June 2022, with 3-months follow-up. The RE-AIM framework was used for process evaluation. Measurements included surveys and interviews, a log of activities (e.g. webinars, social media posts) and engagements (e.g. attendees, reactions to posts), and Google Analytics. Results: There were 29,053 interactions with campaign activities. More than three-quarters of professionals (n = 63/81) thought webinars were very or extremely helpful. Professionals and people with dementia and carers reported that the website provided appropriate content, an approachable tone, and was easy to use. Following campaign engagement, professionals planned to (n = 77/80) or had modified (n = 29/44) how they communicated the diagnosis and/or provided post-diagnostic information and referrals. Qualitative data suggested that the campaign may have led to benefits for some people with dementia and carers. Conclusions: Forward with Dementia was successful in terms of reach, appropriateness, adoption and maintenance for professionals, however flow-through impacts on people with dementia are not clear. Targeted campaigns can potentially change health professionals’ communication and support around chronic diseases such as dementia

Experimental and computational studies of jamming

Jamming is a common feature of out of equilibrium systems showing slow relaxation dynamics. Here we review our efforts in understanding jamming in granular materials using experiments and computer simulations. We first obtain an estimation of an effective temperature for a slowly sheared granular material very close to jamming. The measurement of the effective temperature is realized in the laboratory by slowly shearing a closely-packed ensemble of spherical beads confined by an external pressure in a Couette geometry. All the probe particles, independent of their characteristic features, equilibrate at the same temperature, given by the packing density of the system. This suggests that the effective temperature is a state variable for the nearly jammed system. Then we investigate numerically whether the effective temperature can be obtained from a flat average over the jammed configuration at a given energy in the granular packing, as postulated by the thermodynamic approach to grains.Comment: 20 pages, 9 figure

The habenular nuclei: a conserved asymmetric relay station in the vertebrate brain

The dorsal diencephalon, or epithalamus, contains the bilaterally paired habenular nuclei and the pineal complex. The habenulae form part of the dorsal diencephalic conduction (DDC) system, a highly conserved pathway found in all vertebrates. In this review, we shall describe the neuroanatomy of the DDC, consider its physiology and behavioural involvement, and discuss examples of neural asymmetries within both habenular circuitry and the pineal complex. We will discuss studies in zebrafish, which have examined the organization and development of this circuit, uncovered how asymmetry is represented at the level of individual neurons and determined how such left–right differences arise during development