47,319 research outputs found

    Respect, status and domestic work: Female migrants at home and work

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    The transition from adolescence to adulthood is a complex and often contradictory process for female, ethnic minority, migrant strangers, moving as domestic workers to Delhi, India’s capital. Drawing on empirical work in a village in Jharkhand State, which has witnessed increasing migration of adolescent girls as domestic workers to Delhi over the last two decades, this paper highlights the experience of tribal domestic workers at home and at work. It points to their agency in dealing with the contradictions they face between earning incomes, acquiring markers of status and gaining respect across the urban and rural worlds they stride

    Emerging Bosons with Three-Body Interactions from Spin-1 Atoms in Optical Lattices

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    We study two many-body systems of bosons interacting via an infinite three-body contact repulsion in a lattice: a pairs quasi-condensate induced by correlated hopping and the discrete version of the Pfaffian wavefunction. We propose to experimentally realise systems characterized by such interaction by means of a proper spin-1 lattice Hamiltonian: spin degrees of freedom are locally mapped into occupation numbers of emerging bosons, in a fashion similar to spin-1/2 and hardcore bosons. Such a system can be realized with ultracold spin-1 atoms in a Mott Insulator with filling-factor one. The high versatility of these setups allows us to engineer spin-hopping operators breaking the SU(2) symmetry, as needed to approximate interesting bosonic Hamiltonians with three-body hardcore constraint. For this purpose we combine bichromatic spin-independent superlattices and Raman transitions to induce a different hopping rate for each spin orientation. Finally, we illustrate how our setup could be used to experimentally realize the first setup, i.e. the transition to a pairs quasi-condensed phase of the emerging bosons. We also report on a route towards the realization of a discrete bosonic Pfaffian wavefunction and list some open problems to reach this goal.Comment: 17 pages, 13 figure

    A Comprehensive Analysis of Swarming-based Live Streaming to Leverage Client Heterogeneity

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    Due to missing IP multicast support on an Internet scale, over-the-top media streams are delivered with the help of overlays as used by content delivery networks and their peer-to-peer (P2P) extensions. In this context, mesh/pull-based swarming plays an important role either as pure streaming approach or in combination with tree/push mechanisms. However, the impact of realistic client populations with heterogeneous resources is not yet fully understood. In this technical report, we contribute to closing this gap by mathematically analysing the most basic scheduling mechanisms latest deadline first (LDF) and earliest deadline first (EDF) in a continuous time Markov chain framework and combining them into a simple, yet powerful, mixed strategy to leverage inherent differences in client resources. The main contributions are twofold: (1) a mathematical framework for swarming on random graphs is proposed with a focus on LDF and EDF strategies in heterogeneous scenarios; (2) a mixed strategy, named SchedMix, is proposed that leverages peer heterogeneity. The proposed strategy, SchedMix is shown to outperform the other two strategies using different abstractions: a mean-field theoretic analysis of buffer probabilities, simulations of a stochastic model on random graphs, and a full-stack implementation of a P2P streaming system.Comment: Technical report and supplementary material to http://ieeexplore.ieee.org/document/7497234

    Phase diagram of a Schelling segregation model

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    The collective behavior in a variant of Schelling's segregation model is characterized with methods borrowed from statistical physics, in a context where their relevance was not conspicuous. A measure of segregation based on cluster geometry is defined and several quantities analogous to those used to describe physical lattice models at equilibrium are introduced. This physical approach allows to distinguish quantitatively several regimes and to characterize the transitions between them, leading to the building of a phase diagram. Some of the transitions evoke empirical sudden ethnic turnovers. We also establish links with 'spin-1' models in physics. Our approach provides generic tools to analyze the dynamics of other socio-economic systems

    Multicellular rosettes drive fluid-solid transition in epithelial tissues

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    Models for confluent biological tissues often describe the network formed by cells as a triple-junction network, similar to foams. However, higher order vertices or multicellular rosettes are prevalent in developmental and {\it in vitro} processes and have been recognized as crucial in many important aspects of morphogenesis, disease, and physiology. In this work, we study the influence of rosettes on the mechanics of a confluent tissue. We find that the existence of rosettes in a tissue can greatly influence its rigidity. Using a generalized vertex model and effective medium theory we find a fluid-to-solid transition driven by rosette density and intracellular tensions. This transition exhibits several hallmarks of a second-order phase transition such as a growing correlation length and a universal critical scaling in the vicinity a critical point. Further, we elucidate the nature of rigidity transitions in dense biological tissues and other cellular structures using a generalized Maxwell constraint counting approach. This answers a long-standing puzzle of the origin of solidity in these systems.Comment: 11 pages, 5 figures + 8 pages, 7 figures in Appendix. To be appear in PR

    Taming troubled teens: The social production of mental morbidity amongst young mothers in Pelotas, Brazil

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    Copyright @ 2011 Elsevier Ltd. This is a post-print version of the article. The published version of the article can be viewed at the link below.Explanations for the association between teen-childbearing and subsequent mental morbidity vary considerably, from those based on neurological theories of development to those investigating underlying social and economic determinants. Based on longitudinal epidemiological and ethnographic sub-studies of the 1982 Pelotas birth cohort study, this paper explores the hypothesis that teen childbearing and subsequent mental morbidity have become associated through the interplay of culture, society, and biology in situations where teen pregnancy has become a stigmatised object of scientific and public health attention. Results show that the effect of teen childbearing on subsequent mental morbidity remained significant in the multivariate analysis. Ethnographic analysis, together with epidemiological effect modification analyses, suggest that this association is partially accounted for by the fact that it is more pronounced amongst a specific subgroup of women of low socio-economic status who, being more politicised about societal injustice, were also more critically engaged with – and thus troubled by – the inequitable institutionalisation of life-cycle transitions. With time, these women became highly critical of the institutionalised identification of early childbearing as a key violation of life-cycle norms and the differential class-based application of scientific knowledge on its causes and consequences. Public health campaigns should consider how the age-based institutionalisation of developmental norms has enabled the stigmatisation of those identified as transgressors.The 1982 cohort study has been funded by The Wellcome Trust, the World Health Organisation, the PanAmerican Health Organisation, the European Union, the Programa Nacional para Centros de ExcelĂȘncia (PRONEX), the Conselho Nacional de Desenvolvimento CientĂ­fico e TecnolĂłgico (CNPq), the Brazilian Ministry of Health, and the Fundação de Amparo Ă  Pesquisa do Rio Grande do Sul (Fapergs). D BĂ©hague received support from a US National Science Foundation Doctoral Fellowship and a Postdoctoral Training Fellowship from The Wellcome Trust (Grant no. GR077175MA)
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