Mirror Duality in a Joyce Manifold

Previously the two of the authors defined a notion of dual Calabi-Yau manifolds in a G_2 manifold, and described a process to obtain them. Here we apply this process to a compact G_2 manifold, constructed by Joyce, and as a result we obtain a pair of Borcea-Voisin Calabi-Yau manifolds, which are known to be mirror duals of each other.Comment: 9 pages, 4 figures, revised version, to appear in Advances in Mathematic

Toric LeBrun metrics and Joyce metrics

We show that, on the connected sum of complex projective planes, any toric LeBrun metric can be identified with a Joyce metric admitting a semi-free circle action through an explicit conformal equivalence. A crucial ingredient of the proof is an explicit connection form for toric LeBrun metrics.Comment: 10 page

Tests of chameleon gravity

Theories of modified gravity, where light scalars with non-trivial self-interactions and non-minimal couplings to matter—chameleon and symmetron theories—dynamically suppress deviations from general relativity in the solar system. On other scales, the environmental nature of the screening means that such scalars may be relevant. The highly-nonlinear nature of screening mechanisms means that they evade classical fifth-force searches, and there has been an intense effort towards designing new and novel tests to probe them, both in the laboratory and using astrophysical objects, and by reinterpreting existing datasets. The results of these searches are often presented using different parametrizations, which can make it difficult to compare constraints coming from different probes. The purpose of this review is to summarize the present state-of-the-art searches for screened scalars coupled to matter, and to translate the current bounds into a single parametrization to survey the state of the models. Presently, commonly studied chameleon models are well-constrained but less commonly studied models have large regions of parameter space that are still viable. Symmetron models are constrained well by astrophysical and laboratory tests, but there is a desert separating the two scales where the model is unconstrained. The coupling of chameleons to photons is tightly constrained but the symmetron coupling has yet to be explored. We also summarize the current bounds on f(R) models that exhibit the chameleon mechanism (Hu and Sawicki models). The simplest of these are well constrained by astrophysical probes, but there are currently few reported bounds for theories with higher powers of R. The review ends by discussing the future prospects for constraining screened modified gravity models further using upcoming and planned experiments

Complex hyperkähler structures defined by Donaldson–Thomas invariants

The notion of a Joyce structure was introduced in Bridgeland (Geometry from Donaldson–Thomas invariants, preprint arXiv:1912.06504) to describe the geometric structure on the space of stability conditions of a CY3 category naturally encoded by the Donaldson-Thomas invariants. In this paper we show that a Joyce structure on a complex manifold defines a complex hyperkähler structure on the total space of its tangent bundle, and give a characterisation of the resulting hyperkähler metrics in geometric terms

Cristo '63 di Carmelo Bene. Omaggio a Joyce

In queste pagine si cerca innanzitutto di ricostruire una delle serate più scandalose della scena italiana degli anni '60 con l'intenzione di mostrare la relazione tra la scrittura scenica beniana e il linguaggio dei romanzi di J. Joyce. Cristo '63 infatti si presenta nella sua unicità come una possibilità per capire “l’applicazione” che Bene fece dell’Ulisse in scena

Resettlement experiences and resilience in refugee youth in Perth, Western Australia

Background: In Australia, the two major pathways of refugee entry are the United Nations High Commissioner for Refugees resettlement programme and irregular maritime arrivals (IMAs) seeking asylum. The Australian Government’s policies towards IMAs since July 2013 are controversial, uncompromising and consistently harsh, with asylum seekers held in detention centres for prolonged periods. Refugees and asylum seekers have distinct and unique stressors that make resettlement difficult. Methods: This exploratory study examines resettlement experiences for refugee youth in Western Australia using the psychosocial conceptual framework and qualitative methods. Focus group discussions and key informant interviews were undertaken with verbatim transcripts analysed using thematic analysis to identify themes. Results: Themes documented that language and its impact, and experience with education, health, and social activities, support structures provided to youth and supporting future aspirations as critical to successful resettlement. This exploratory study contributes to developing a broader understanding of the resettlement experiences of refugee youth, drawing on their current and past experiences, cultural differences and mechanisms for coping. Conclusion: Fluency in English language, especially spoken, was a facilitator of successful resettlement. Our results align with previous studies documenting that support programs are vital for successful resettlement. Although faced with immense difficulties refugee youth are resilient, want to succeed and have aspirations for the future. Strategies and recommendations suggested by refugee youth themselves could be used for developing interventions to assist successful resettlement

Andal Priyadarshini's the Position of Women in the Working Class

Singing songs about God, the king, and upper castes are mostly found in Tamil literature. The singing of working class people is rarely found in a few pieces of literature like Pallu (Agriculture Songs) and Kuravanchi. Modern literature gives complete freedom to sing about the working class. In it, Andal Priyadarshini has created modern literature such as poetry, short stories, novels, etc. In it, the creators have made the lower class people aware of their life status by singing and creating characters. Her works frequently depict hustlers, roadside dwellers, scavengers, cremators, and transgender women and girls. They are the members of society. Some are working people, who have every right to live here, and are economically backward. People have continued their lives at the bottom of society for centuries. Mere pity for the working class will not lift them up. If individual value, castelessness, labour value, and non-discrimination come together, then a society called the working class will disappear

A Multiprocessor Implementation of Joyce

Joyce is a programming language for parallel computers based on CSP and Pascal. A Joyce program defines concurrent agents which communicate through unbuffered channels. This paper describes a multiprocessor implementation of Joyce