47,319 research outputs found
Respect, status and domestic work: Female migrants at home and work
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, Indiaâs 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
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
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
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
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Thunderstriking constraints with JUPITER
We present JUPITER, a tool for analysing multi-constrained systems. JUPITER was built to explore three basic ideas. First, how to use controller synthesis so as to find the exact conditions under which a particular constraint will be satisfied. Second, how to successively refine the models used for the controller synthesis so as to obtain a series of more easily understandable and more robust controllers. Last but not least, how to structure & explain the synthesised controllers and provide hints to designers for further optimisations through the use of machine learning techniques. Thus, JUPITER can help in the design and analysis of multi-constraint systems through the automatic synthesis of control logic for certain of the constraints and the aid it provides to designers for discovering further optimisations. The controllers it synthesises can be easily implemented on top of a standard real-time OS
Multicellular rosettes drive fluid-solid transition in epithelial tissues
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
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 â and thus troubled by â 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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