779 research outputs found

    Spinful bosons in an optical lattice

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    We analyze the behavior of cold spin-1 particles with antiferromagnetic interactions in a one-dimensional optical lattice using density matrix renormalization group calculations. Correlation functions and the dimerization are shown and we also present results for the energy gap between ground state and the spin excited states. We confirm the anticipated phase diagram, with Mott-insulating regions of alternating dimerized S=1 chains for odd particle density versus on-site singlets for even density. We find no evidence for any additional ordered phases in the physically accessible region, however for sufficiently large spin interaction, on-site singlet pairs dominate leading, for odd density, to a breakdown of the Mott insulator or, for even density, a real-space singlet superfluid.Comment: Minor revisions and clarification

    Body weight and colorectal cancer risk in a cohort of Swedish women: relation varies by age and cancer site

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    The relation between relative body weight and colorectal cancer among women is unclear. In a large prospective cohort study, we found a positive association only for distal cancers among younger women that became attenuated at older ages. These results support previous reports in which results were stratified by age or colorectal cancer site. © 2001 Cancer Research Campaign http://www.bjcancer.co

    One-dimensional phase transitions in a two-dimensional optical lattice

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    A phase transition for bosonic atoms in a two-dimensional anisotropic optical lattice is considered. If the tunnelling rates in two directions are different, the system can undergo a transition between a two-dimensional superfluid and a one-dimensional Mott insulating array of strongly coupled tubes. The connection to other lattice models is exploited in order to better understand the phase transition. Critical properties are obtained using quantum Monte Carlo calculations. These critical properties are related to correlation properties of the bosons and a criterion for commensurate filling is established.Comment: 14 pages, 8 figure

    Changes in addressing inequalities in access to hospital care in Andhra Pradesh and Maharashtra states of India: a difference-in-differences study using repeated cross-sectional surveys

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    Objectives To compare the effects of the Rajiv Aarogyasri Health Insurance Scheme of Andhra Pradesh (AP) with health financing innovations including the Rashtriya Swasthya Bima Yojana (RSBY) in Maharashtra (MH) over time on access to and out-of-pocket expenditure (OOPE) on hospital inpatient care. Study design A difference-in-differences (DID) study using repeated cross-sectional surveys with parallel control. Setting National Sample Survey Organisation of India (NSSO) urban and rural ‘first stratum units’, 863 in AP and 1008 in MH. Methods We used two cross-sectional surveys: as a baseline, the data from the NSSO 2004 survey collected before the Aarogyasri and RSBY schemes were launched; and as postintervention, a survey using the same methodology conducted in 2012. Participants 8623 households in AP and 10 073 in MH. Main outcome measures Average OOPE, large OOPE and large borrowing per household per year for inpatient care, hospitalisation rate per 1000 population per year. Results Average expenditure, large expenditures and large borrowings on inpatient care had increased in MH and AP, but the increase was smaller in AP across these three measures. DIDs for average expenditure and large borrowings were significant and in favour of AP for the rural and the poorest households. Hospitalisation rates also increased in both states but more so in AP, although the DID was not significant and the subgroup analysis presented a mixed picture. Conclusions Health innovations in AP had a greater beneficial effect on inpatient care-related expenditures than innovations in MH. The Aarogyasri scheme is likely to have contributed to these impacts in AP, at least in part. However, OOPE increased in both states over time. Schemes such as the Aarogyasri and RSBY may result in some positive outcomes, but additional interventions may be required to improve access to care for the most vulnerable sections of the population

    The Best Laid Plans: Access to the Rajiv Aarogyasri community health insurance scheme of Andhra Pradesh

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    This paper is a qualitative assessment of a public health insurance scheme in the state of Andhra Pradesh, south India, called the Rajiv Aarogyasri Community Health Insurance Scheme (or Aarogyasri), using the case-study method. Focusing on inpatient hospital care and especially on surgical treatments leaves the scheme wanting in meeting the health care needs of and addressing the impoverishing health expenditure incurred by the poor, especially those living in rural areas. Though well-intentioned, people from vulnerable sections of society may find the scheme ultimately unhelpful for their needs. Through an in-depth qualitative approach, the paper highlights not just financial difficulties but also the non-financial barriers to accessing health care, despite the existence of a scheme such as Aarogyasri. Narrative evidence from poor households offers powerful insights into why even the most innovative state health insurance schemes may not achieve their goals and systemic corrections needed to address barriers to health care
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