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    Meet the Parents: The Progenitor Binary for the Supermassive Black Hole Candidate in E1821+643
    Paynter, J ; Thrane, E (IOP Publishing Ltd, 2023-03-01)
    Abstract The remnants of binary black hole mergers can be given recoil kick velocities up to 5000 km s−1 due to anisotropic emission of gravitational waves. E1821+643 is a recoiling supermassive black hole candidate with spectroscopically offset, broad emission lines, consistent with motion of the black hole at ∼2100 km s−1 along the line of sight relative to its host galaxy. This suggests a recoil kick of ∼2200 km s−1. Such a kick is powerful enough to eject E1821+643 from its M gal ∼ 2 × 1012 M ⊙ host galaxy. In this work, we address the question: assuming that E1821+643 is a recoiling black hole, what are the likely properties of the progenitor binary that formed E1821+643? Using astrophysically motivated priors, we infer that E1821+643 was likely formed from a binary black hole system with masses of m 1 ∼ 1.9 − 0.4 + 0.5 × 10 9 M ⊙ , m 2 ∼ 8.1 − 3.2 + 3.9 × 10 8 M ⊙ (90% credible intervals). Given our model, the black holes in this binary were likely to be spinning rapidly with dimensionless spin magnitudes of χ 1 = 0.87 − 0.26 + 0.11 , χ 2 = 0.77 − 0.37 + 0.19 . Such a high recoil velocity is impossible for spins aligned to the orbital angular momentum axis. This suggests that the progenitor for E1821+643 merged in hot gas, which is thought to provide an environment where spin alignment from accretion proceeds slowly relative to the merger timescale. We infer that E1821+643, if it is a recoiling black hole, is likely to be a rapidly rotating black hole with a dimensionless spin of χ = 0.92 ± 0.04. A 2.6 × 109 M ⊙ black hole, recoiling from a gas-rich environment at v ∼ 2200 km s−1, is likely to persist as an active galactic nucleus for ∼107 yr, in which time it traverses ∼25 kpc.
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    Mathematical models of Plasmodium vivax transmission: A scoping review
    Anwar, MN ; Smith, L ; Devine, A ; Mehra, S ; Walker, CR ; Ivory, E ; Conway, E ; Mueller, I ; Mccaw, JM ; Flegg, JA ; Hickson, RI ; ten Bosch, Q (PUBLIC LIBRARY SCIENCE, 2024-03)
    Plasmodium vivax is one of the most geographically widespread malaria parasites in the world, primarily found across South-East Asia, Latin America, and parts of Africa. One of the significant characteristics of the P. vivax parasite is its ability to remain dormant in the human liver as hypnozoites and subsequently reactivate after the initial infection (i.e. relapse infections). Mathematical modelling approaches have been widely applied to understand P. vivax dynamics and predict the impact of intervention outcomes. Models that capture P. vivax dynamics differ from those that capture P. falciparum dynamics, as they must account for relapses caused by the activation of hypnozoites. In this article, we provide a scoping review of mathematical models that capture P. vivax transmission dynamics published between January 1988 and May 2023. The primary objective of this work is to provide a comprehensive summary of the mathematical models and techniques used to model P. vivax dynamics. In doing so, we aim to assist researchers working on mathematical epidemiology, disease transmission, and other aspects of P. vivax malaria by highlighting best practices in currently published models and highlighting where further model development is required. We categorise P. vivax models according to whether a deterministic or agent-based approach was used. We provide an overview of the different strategies used to incorporate the parasite's biology, use of multiple scales (within-host and population-level), superinfection, immunity, and treatment interventions. In most of the published literature, the rationale for different modelling approaches was driven by the research question at hand. Some models focus on the parasites' complicated biology, while others incorporate simplified assumptions to avoid model complexity. Overall, the existing literature on mathematical models for P. vivax encompasses various aspects of the parasite's dynamics. We recommend that future research should focus on refining how key aspects of P. vivax dynamics are modelled, including spatial heterogeneity in exposure risk and heterogeneity in susceptibility to infection, the accumulation of hypnozoite variation, the interaction between P. falciparum and P. vivax, acquisition of immunity, and recovery under superinfection.
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    Electric field enhancement in Au and Ag nanodisks-based photonic crystals: Relevant design insights for efficient SERS substrates
    Roa, S ; Akinoglu, GE ; Pedano, ML (Elsevier, 2023-07)
    In recent years, noble metal nanoparticle-based periodic nanoarrays (photonic crystals) have received special attention due to their gross potential to achieve exceptionally high Electric-Near Field Enhancement (ENFE) factors for visible light and their prospects as candidates for the fabrication of ultra-sensitive Surface-Enhanced Raman Spectroscopy (SERS) substrates. In this work, we report a simple but exhaustive theoretical analysis of the ENFE in Au and Ag nanodisks-based photonic crystals by Finite-Difference Time-Domain (FDTD) method. Nanostructures with arrays periodicities from 200 to 1000 [nm], nanodisks diameters from 100 to 500 [nm] and thicknesses from 20 to 200 [nm] were studied. Results show that the ENFE is strongly dependent on each one of these geometrical parameters, observing |E/E0|2 factors that can reach up to 1200 for the visible light spectrum. The effects of nanodisks surface curvature-based defects on the ENFE were also analyzed. This kind of defects seem to be also relevant to maximize the ENFE effects, observing that higher surface curvatures tend to considerably attenuate the electric field amplification. Our research provides relevant insights on the design optimization of this kind of photonic crystals to maximize the ENFE effects, which is a critical issue to assess the future fabrication conditions of efficient SERS substrates.
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    From unknown to known: interpreting songlines through gracious engagements from Australia to Indonesia
    Curkpatrick, S ; Pawu, WJ ; Susanto, H ( 2024)
    In this article, we explore interpretive approaches within Warlpiri (Aboriginal Australian) song and narrative that underpin ngurra-kurlu, a pattern for living purposefully among others. For Warlpiri scholar Author 2, ngurra-kurlu shapes hermeneutic activity, within traditional contexts and across cultural and religious differences. Demonstrating the expansive scope of traditional Warlpiri epistemology, we interpose ngurra-kurlu with the experience of Christians in Indonesia, as they navigate challenges of identity and belonging in this majority Muslim nation. In this, we consider theology as an attentiveness to the gift of variegated traditions. As a movement from unknown to known, theology sustains vibrant community and relational growth.
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    Symbolic cohesion and interpretive freedom: Embodying unity in diversity through Warlpiri ngurra-kurlu and Indonesian Pancasila
    Curkpatrick, S ; Susanto, H ; Pawu, WJ ( 2024)
    Within contemporary Australian and Indonesian society, cultural and religious diversity is often celebrated as symbolic of broader liberal and pluralist identities. However, the interpretive traditions of Indigenous and other minorities are seemingly, rarely considered integral to shaping mainstream discourses on social cohesion. In this article, we explore two contexts of minority engagement with aspirations of unity in diversity, namely Warlpiri Australian formulations of kinship through ngurru-kurlu and Indonesian Christian engagement with Pancasila. Showing the potential for these perspectives to enrich broader social discourse, we suggest that similarities in the symbolic structure of these frameworks can stimulate the exploration of mutual responsibilities across diverse cultural settings. Further, we argue that intimations of gift in traditional Warlpiri ceremony and Christian experience, provide an impetus to this endeavour. Interpretations of ngurra-kurlu and Pancasila as gift are considered integral to the realisation of unity in diversity, embodied within specific contexts of human engagement.
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    Resounding relations: Habits of improvisation in Yolŋu song and contemporary Australian jazz
    Curkpatrick, S ; Burke, R ; Gaby, A ; Wilfred, D ; Knight, P (Taylor and Francis Group, 2024)
    Habit has primarily been considered along seemingly divergent trajectories, either as a mechanism that limits creativity or as a transition of imagination into embodied activity (Grosz 2013). An interplay of these two aspects is clearly seen in music improvisation, in which performances unfold through well-honed patterns of technique and processes of listening and learning. Yet while the development of good habits is considered essential to performance within distinct cultural traditions or stylistic genres, little attention has been devoted to identifying the types of habits needed for engagement in cross-cultural performance settings. This paper broadens the scope of habits typically explored within jazz studies and music pedagogy, conceptualising habit in a way that resonates across contemporary Australian jazz and Yolŋu manikay (public ceremonial song) from Australia’s Northern Territory. In this, we emphasize the relational dimensions of habit as they form a foundation for community formation through performance, involving processes of imitation and evocation, and learning through participation. Through this heuristic braiding of habits in jazz and manikay, we argue that habits of musical performance both locate performers within distinct traditions while allowing freedom to innovate. This dynamic allows for the elevation of these traditions within new contexts and relationships.
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    Dislocation, Resilience and Change: Three Openings on Togetherness within Australian Music-making
    Curkpatrick, S ; Case, L ; Skinner, A (Taylor and Francis Group, 2024)
    Realities of human dislocation present significant challenges to understandings of social togetherness. As such, a contemporary focus on inherited inequalities, discrimination and exclusion seems at odds with an enthusiasm for what might be held in common. In this article, we seek to reframe experiences of dislocation through three perspectives drawn from Australian music-making. While identifying challenges of inclusion and engagement within Australian history and society, we affirm the possibility for resilient and respectful relationships to be built across diverse experiences. Observations build from research on disability culture (Skinner), Indigenous engagement with western instruments (Case) and cross-cultural collaboration (Curkpatrick). Where Charles Taylor has defined social imaginaries as ‘common understanding which makes possible common practices’ (2007: 172), these perspectives show how human creativity is enabled by shared experiences and our basic materiality as proximate, relational individuals. Unique scenes of music performance are described as they shape new ways of relating and being within diverse communities, as a generative force for social change.
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    The Wind is Always Blowing: Generative Crosscurrents of Ethnographic Dialogue in Australia
    Curkpatrick, S ; Wilfred, D (Wiley, 2024)
    Live conversations and writing play an important role in ethnographic research that seeks to develop understanding across cultural differences. Both forms of communication need not remain distinct: written dialogue can develop critical thought while foregrounding the shared contexts and relational impetuses of communication across cultures. Set against the background of recent styles in ethnographic writing about and with Yolŋu people, this article extends from conversations about wata (wind), exploring collaborative practices (music performance and teaching) and approaches to writing ethnography that respond to a core quality of wind as a medium that connects. Wata is a significant theme within manikay (public ceremonial song) that connects Wägilak with their ancestral lands, even as it blows through the country of other groups, allowing new relationships and understandings to be formed. Giving rise to concerns of connection, difference, and movement, wata is a significant theme for considering the ways narrative traditions can shape relationality and give impetus to intellectual inquiry.
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    Converging Currents: Memories of Migration, Diplomacy and the Gathering Winds of Ngukurr
    Curkpatrick, S ; Wilfred, D ; Peters, AL ; Haley, K (Simon Normand, 2022)
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