1,072 research outputs found
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
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 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 âideological complexâ 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
Thinking about Later Life: Insights from the Capability Approach
A major criticism of mainstream gerontological frameworks is the inability of such frameworks to appreciate and incorporate issues of diversity and difference in engaging with experiences of aging. Given the prevailing socially structured nature of inequalities, such differences matter greatly in shaping experiences, as well as social constructions, of aging. I argue that Amartya Senâs capability approach (2009) potentially offers gerontological scholars a broad conceptual framework that places at its core consideration of human beings (their values) and centrality of human diversity. As well as identifying these key features of the capability approach, I discuss and demonstrate their relevance to thinking about old age and aging. I maintain that in the context of complex and emerging identities in later life that shape and are shaped by shifting people-place and people-people relationships, Senâs capability approach offers significant possibilities for gerontological research
Linguistic imperialism: still a valid construct in relation to language policy for Irish Sign Language
Native-English-Speaking Teachers:Disconnections Between Theory, Research, and Practice
Native-English-speaking teachers (NESTs) have long been in demand for perceived benefits of the skills they bring to the classroom. However, the notion that native speakers provide the best models of the target language and thus make the best teachers of the language has been criticised in the literature. This article reports on the disconnection between academic literature on NESTs and the realities they report. Drawing on data from an investigation into NEST schemes globally, the article suggests that lived classroom experiences of NESTs are complex, They are also often bilingual, experienced, and qualified, and regard local English teachers (LETs) they work with as experts and in control of how English is practised in the classroom. These characteristics contrast with much of the academic literature, which explores the concept of native speakerism, which tends to view NESTs negatively. The article proposes that one reason for the disconnection between theory and practice is the parallel lives of researchers and teachers, whether NESTs or LETs. Thus, each groupâs realities and concerns are not always understood by the other. The article suggests that a substantial group of bilingual and bicultural NESTs consider the country where work home, so future theorisations of NESTs and native speakerism should take account of these teachers
Issues of ideology in English language education worldwide: an overview
The relatively limited consideration of ideology in mainstream theory and research of teaching the English language to speakers of other languages has arguably prevented the problematization of many taken-for-granted perceptions and practices of the field. In this article I attempt to bring part of this marginalized body of scholarship on issues of ideology in the area of English language teaching (ELT) to highlight its potential insights for the field. The article sets out from a view of ideology as the most fundamental beliefs in any social practice, which may provide a less-formidable conception of the term and lessen the divergence among the minority of ELT researchers and professionals that do concern themselves with ideology. Then, after a brief sketch of the notion of ideology of language (education), I present an overview of aspects of this marginal but vibrant stream of thought on issues of ideology in ELT worldwide. Overall, the discussion is aimed to act as a call for the further understanding and embracement of sociopolitically-sensitive and ideologically-informed approaches to ELT theory, research, and practice
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