2,335 research outputs found
Neighbourhoods and self rated health: a comparison of public sector employees in London and Helsinki
Study objective: Mortality and morbidity vary across neighbourhoods and larger residential areas. Effects of area deprivation on health may vary across countries, because of greater spatial separation of people occupying high and low socioeconomic positions and differences in the provision of local services and facilities. Neighbourhood variations in health and the contribution of residents' characteristics and neighbourhood indicators were compared in London and Helsinki, two settings where inequality and welfare policies differ.Design: Data from two cohorts were used to investigate associations between self rated health and neighbourhood indicators using a multilevel approach.Setting: London and Helsinki.Participants: From the Whitehall II study (London, aged 39-63) and the Helsinki health study (aged 40-60).Main results: Socioeconomic segregation was higher in London than in Helsinki. Age and sex adjusted differences in self rated health between neighbourhoods were also greater in London. Independent of individual socioeconomic position, neighbourhood unemployment, proportion of residents in manual occupations, and proportion of single households were associated with health. In pooled data, residence in a neighbourhood with highest unemployment was associated with an odds ratio of less than good self rated health of 1.51 (95% CI 1.30 to 1.75). High rates of single parenthood were associated with health in London but not in Helsinki.Conclusions: Neighbourhood socioeconomic context was associated with health in both countries, with some evidence of greater neighbourhood effects in London. Greater socioeconomic segregation in London may have emergent effects at the neighbourhood level. Local and national social policies may reduce, or restrict, inequality and segregation between areas
Superfluid phases of fermions with hybridized and orbitals
We explore the superfluid phases of a two-component Fermi mixture with
hybridized orbitals in optical lattices. We show that there exists a general
mapping of this system to the Lieb lattice. By using simple multiband models
with hopping between and -orbital states, we show that superfluid order
parameters can have a -phase difference between lattice sites, which is
distinct from the case with hopping between -orbitals. If the population
imbalance between the two spin species is tuned, the superfluid phase may
evolve through various phases due to the interplay between hopping,
interactions and imbalance. We show that the rich behavior is observable in
experimentally realizable systems.Comment: 13 pages, 11 figures. Published versio
Noise correlations of the ultra-cold Fermi gas in an optical lattice
In this paper we study the density noise correlations of the two component
Fermi gas in optical lattices. Three different type of phases, the BCS-state
(Bardeen, Cooper, and Schieffer), the FFLO-state (Fulde, Ferrel, Larkin, and
Ovchinnikov), and BP (breach pair) state, are considered. We show how these
states differ in their noise correlations. The noise correlations are
calculated not only at zero temperature, but also at non-zero temperatures
paying particular attention to how much the finite temperature effects might
complicate the detection of different phases. Since one-dimensional systems
have been shown to be very promising candidates to observe FFLO states, we
apply our results also to the computation of correlation signals in a
one-dimensional lattice. We find that the density noise correlations reveal
important information about the structure of the underlying order parameter as
well as about the quasiparticle dispersions.Comment: 25 pages, 11 figures. Some figures are updated and text has been
modifie
Quantum fluctuations of a vortex in an optical lattice
Using a variational ansatz for the wave function of the Bose-Einstein
condensate, we develop a quantum theory of vortices and quadrupole modes in a
one-dimensional optical lattice. We study the coupling between the quadrupole
modes and Kelvin modes, which turns out to be formally analogous to the theory
of parametric processes in quantum optics. This leads to the possibility of
squeezing vortices. We solve the quantum multimode problem for the Kelvin modes
and quadrupole modes numerically and find properties that cannot be explained
with a simple linear-response theory.Comment: final version, minor change
Four-year trajectories of episodic memory decline in mid-late life by living arrangements: a cross-national comparison between China and England
BACKGROUND: There is mixed evidence on the association between living arrangements and mid-late life cognition, which may be due to distinct familial arrangements and preferences between populations. To address such heterogeneity, we assessed these associations in China and England.
METHODS: Four-year trajectories of episodic memory scores (0–20, word recall test) by living arrangements (living with partner only, living with partner and children/grandchildren, living with no partner but with children/grandchildren, and living alone) were estimated using latent growth curve modelling for men and women aged 50+ from China (n=12 801) and England (n=10 964).
RESULTS: After adjusting for baseline socioeconomic, health behaviours and health covariates, worse baseline memory was found in Chinese adults living with no partner but with children/grandchildren and in Chinese women living with partner and children/grandchildren, compared with those living with partner only. Better baseline memory was associated with living alone in English women. A faster memory decline was found in Chinese men living with no partner but with children/grandchildren (−0.122 word/year, 95% CI −0.213 to –0.031), as well as in English women living with children/grandchildren with (−0.114, 95% CI −0.180 to –0.049) or without (−0.118, 95% CI −0.209 to –0.026) a partner, and those living alone (−0.075, 95% CI −0.127 to –0.024). No differences at baseline nor over follow-up were found between English men in different living arrangements.
CONCLUSIONS: Overall, our findings did not confirm the protective effects of co-residence with children/grandchildren, nor the detrimental effects of living alone on mid-late life cognition in China and England
Trends in mortality by labour market position around retirement ages in three European countries with different welfare regimes
<p>Objectives: In the face of economic downturn and increasing life expectancy, many industrial nations are adopting a policy of postponing the retirement age. However, questions still remain around the consequence of working longer into old age. We examine mortality by work status around retirement ages in countries with different welfare regimes; Finland (social democratic), Turin (Italy; conservative), and England and Wales (liberal).</p>
<p>Methods: Death rates and rate ratios (RRs) (reference rates = ‘in-work’), 1970 s–2000 s, were estimated for those aged 45–64 years using the England and Wales longitudinal study, Turin longitudinal study, and the Finnish linked register study.</p>
<p>Results: Mortality of the not-in-work was consistently higher than the in-work. Death rates for the not-in-work were lowest in Turin and highest in Finland. Rate ratios were smallest in Turin (RR men 1972–76 1.73; 2002–06 1.63; women 1.22; 1.68) and largest in Finland (RR men 1991–95 3.03; 2001–05 3.80; women 3.62; 4.11). Unlike RRs for men, RRs for women increased in every country (greatest in Finland).</p>
<p>Conclusions: These findings signal that overall, employment in later life is associated with lower mortality, regardless of welfare regime.</p>
Quantum theory of a vortex line in an optical lattice
We investigate the quantum theory of a vortex line in a stack of
weakly-coupled two-dimensional Bose-Einstein condensates, that is created by a
one-dimensional optical lattice. We derive the dispersion relation of the
Kelvin modes of the vortex line and also study the coupling between the Kelvin
modes and the quadrupole modes. We solve the coupled dynamics of the vortex
line and the quadrupole modes, both classically as well as quantum
mechanically. The quantum mechanical solution reveals the possibility of
generating nonequilibrium squeezed vortex states by strongly driving the
quadrupole modes.Comment: Minor changes in response to a referee repor
Vortex oscillations in confined Bose-Einstein condensate interacting with 1D optical lattice
We study Bose-Einstein condensate of atomic Boson gases trapped in a
composite potential of a harmonic potential and an optical lattice potential.
We found a series of collective excitations that induces localized vortex
oscillations with a characteristic wavelength. The oscillations might be
observed experimentally when radial confinement is tight. We present the
excitation spectra of the vortex oscillation modes and propose a way to
experimentally excite the modes.Comment: 5 pages, 7 figures. Title, abstract and references are update
Stability of small amplitude normal modes of a Bose-Einstein condensate with a singly quantized vortex confined in an optical lattice
We study the dynamics of a BEC with a singly quantized vortex, placed in the
combined potential of a 1-D (2-D) optical lattice and an axi-symmetric harmonic
trap. A time-dependent variational Lagrangian analysis shows that an optical
lattice helps to stabilize the vortex which in absence of the optical lattice
is unstable. We find that the normal modes are stable only if the depth of the
optical potential is more than a certain critical value. This critical value of
the optical potential depends on the interaction parameter.In general higher
the interaction parameter,lower the value of the optical potential required to
stabilize the vortex. The BEC with the singly quantized vortex is found to be
relatively more unstable in a 2-D optical lattice compared to a 1-D optical
lattice.Comment: Revised version with 11 pages including 1 figur
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