Dual Fermion Dynamical Cluster Approach for Strongly Correlated Systems

We have designed a new multi-scale approach for Strongly Correlated Systems by combining the Dynamical Cluster Approximation (DCA) and the recently introduced dual-fermion formalism. This approach employs an exact mapping from a real lattice to a DCA cluster of linear size Lc embedded in a dual fermion lattice. Short-length-scale physics is addressed by the DCA cluster calculation, while longer-length-scale physics is addressed diagrammatically using dual fermions. The bare and dressed dual Fermionic Green functions scale as O(1/Lc) so perturbation theory on the dual lattice converges very quickly. E.g., the dual Fermion self-energy calculated with simple second order perturbation theory is of order O(1/Lc^3), with third order and three body corrections down by an additional factor of O(1/Lc^2)

Examining the “Urban Advantage” in Maternal Health Care in Developing Countries

Andrew Channon and colleagues outline the complexities of urban advantage in maternal health where the urban poor often have worse access to health care than women in rural areas

Solving the Parquet Equations for the Hubbard Model beyond Weak Coupling

We find that imposing the crossing symmetry in the iteration process considerably extends the range of convergence for solutions of the parquet equations for the Hubbard model. When the crossing symmetry is not imposed, the convergence of both simple iteration and more complicated continuous loading (homotopy) methods are limited to high temperatures and weak interactions. We modify the algorithm to impose the crossing symmetry without increasing the computational complexity. We also imposed time reversal and a subset of the point group symmetries, but they did not further improve the convergence. We elaborate the details of the latency hiding scheme which can significantly improve the performance in the computational implementation. With these modifications, stable solutions for the parquet equations can be obtained by iteration more quickly even for values of the interaction that are a significant fraction of the bandwidth and for temperatures that are much smaller than the bandwidth. This may represent a crucial step towards the solution of two-particle field theories for correlated electron models.Comment: 15 pages, 12 figure

Factors influencing feeding practices of extreme poor infants and young children in families of working mothers in Dhaka slums: A qualitative study

BackgroundNutritional status differs between infants and young children living in slum and non-slum conditions—infants and young children living in City Corporation slums are likely to have worse nutritional status compared to those from non-slums. Furthermore, families in slums tend to engage female labor in cash-earning activities as a survival strategy; hence, a higher percentage of mothers stay at work. However, little is known about feeding practices for infants and young children in families with working mothers in slums. This study aims to understand the factors that determine feeding practices for infants and young children living in families with working mothers in Dhaka slums.MethodsThis study adopted a qualitative approach. Sixteen In-depth Interviews, five Key Informant Interviews, and Focused Group Discussions were conducted with family members, community leaders, and program staff. Method triangulation and thematic analyses were conducted.ResultsFeeding practices for infants and young children in families with working mothers are broadly determined by mothers’ occupation, basis civic facilities, and limited family buying capacity. Although mothers have good nutritional knowledge, they negotiate between work and feeding their infants and young children. Household composition, access to cooking facilities, and poverty level were also found to be significant determining factors.ConclusionThe results suggest a trade-off between mothers’ work and childcare. The absence of alternative care support in homes and/or work places along with societal factors outweighs full benefits of project interventions. Improving alternative childcare support could reduce the burden of feeding practice experienced by working mothers and may improve nutritional outcomes

Maternal health in resource-poor urban settings: how does women's autonomy influence the utilization of obstetric care services?

Background: Despite various international efforts initiated to improve maternal health, morethan half a million women worldwide die each year as a result of complications arising frompregnancy and childbirth. This research was guided by the following questions: 1) How doeswomen's autonomy influence the choice of place of delivery in resource-poor urban settings? 2)Does its effect vary by household wealth? and 3) To what extent does women's autonomy mediatethe relationship between women's education and use of health facility for delivery?Methods: The data used is from a maternal health study carried out in the slums of Nairobi, Kenya.A total of 1,927 women (out of 2,482) who had a pregnancy outcome in 2004–2005 were selectedand interviewed. Seventeen variable items on autonomy were used to construct women's decisionmaking,freedom of movement, and overall autonomy. Further, all health facilities serving the studypopulation were assessed with regard to the number, training and competency of obstetric staff;services offered; physical infrastructure; and availability, adequacy and functional status of suppliesand other essential equipment for safe delivery, among others. A total of 25 facilities weresurveyed.Results: While household wealth, education and demographic and health covariates had strongrelationships with place of delivery, the effects of women's overall autonomy, decision-making andfreedom of movement were rather weak. Among middle to least poor households, all threemeasures of women's autonomy were associated with place of delivery, and in the expecteddirection; whereas among the poorest women, they were strong and counter-intuitive. Finally, thestudy showed that autonomy may not be a major mediator of the link between education and useof health services for delivery.Conclusion: The paper argues in favor of broad actions to increase women's autonomy both asan end and as a means to facilitate improved reproductive health outcomes. It also supports thecall for more appropriate data that could further support this line of action. It highlights the needfor efforts to improve households' livelihoods and increase girls' schooling to alter perceptions ofthe value of skilled maternal health care

Reproductive health for refugees by refugees in Guinea III: maternal health

BACKGROUND: Maternal mortality can be particularly high in conflict and chronic emergency settings, partly due to inaccessible maternal care. This paper examines associations of refugee-led health education, formal education, age, and parity on maternal knowledge, attitudes, and practices among reproductive-age women in refugee camps in Guinea. METHODS: Data comes from a 1999 cross-sectional survey of 444 female refugees in 23 camps. Associations of reported maternal health outcomes with exposure to health education (exposed versus unexposed), formal education (none versus some), age (adolescent versus adult), or parity (nulliparous, parous, grand multiparous), were analysed using logistic regression. RESULTS: No significant differences were found in maternal knowledge or attitudes. Virtually all respondents said pregnant women should attend antenatal care and knew the importance of tetanus vaccination. Most recognised abdominal pain (75%) and headaches (24%) as maternal danger signs and recommended facility attendance for danger signs. Most had last delivered at a facility (67%), mainly for safety reasons (99%). Higher odds of facility delivery were found for those exposed to RHG health education (adjusted odds ratio 2.03, 95%CI 1.23-3.01), formally educated (adjusted OR 1.93, 95%CI 1.05-3.92), or grand multipara (adjusted OR 2.13, 95%CI 1.21-3.75). Main reasons for delivering at home were distance to a facility (94%) and privacy (55%). CONCLUSIONS: Refugee-led maternal health education appeared to increase facility delivery for these refugee women. Improved knowledge of danger signs and the importance of skilled birth attendance, while vital, may be less important in chronic emergency settings than improving facility access where quality of care is acceptable

Congo Basin peatlands: threats and conservation priorities

The recent publication of the first spatially explicit map of peatlands in the Cuvette Centrale, central Congo Basin, reveals it to be the most extensive tropical peatland complex, at ca. 145,500 km2. With an estimated 30.6 Pg of carbon stored in these peatlands, there are now questions about whether these carbon stocks are under threat and, if so, what can be done to protect them. Here, we analyse the potential threats to Congo Basin peat carbon stocks and identify knowledge gaps in relation to these threats, and to how the peatland systems might respond. Climate change emerges as a particularly pressing concern, given its potential to destabilise carbon stocks across the whole area. Socio-economic developments are increasing across central Africa and, whilst much of the peatland area is protected on paper by some form of conservation designation, the potential exists for hydrocarbon exploration, logging, plantations and other forms of disturbance to significantly damage the peatland ecosystems. The low level of human intervention at present suggests that the opportunity still exists to protect the peatlands in a largely intact state, possibly drawing on climate change mitigation funding, which can be used not only to protect the peat carbon pool but also to improve the livelihoods of people living in and around these peatlands

Neonatal mortality: an invisible and marginalised trauma

Neonatal mortality is a major health problem in low and middle income countries and the rate of improvement of newborn survival is slow. This article is a review of the PhD thesis by Mats Målqvist, titled ‘Who can save the unseen – Studies on neonatal mortality in Quang Ninh province, Vietnam,’ from Uppsala University. The thesis aims to investigate structural barriers to newborn health improvements and determinants of neonatal death. The findings reveal a severe under-reporting of neonatal deaths in the official health statistics in Quang Ninh province in northern Vietnam. The neonatal mortality rate (NMR) found was four times higher than what was reported to the Ministry of Health. This underestimation of the problem inhibits adequate interventions and efforts to improve the survival of newborns and highlights the invisibility of this vulnerable group

Influence of Birth Preparedness, Decision-Making on Location of Birth and Assistance by Skilled Birth Attendants among Women in South-Western Uganda

Introduction: Assistance by skilled birth attendants (SBAs) during childbirth is one of the strategies aimed at reducing maternal morbidity and mortality in low-income countries. However, the relationship between birth preparedness and decision-making on location of birth and assistance by skilled birth attendants in this context is not well studied. The aim of this study was to assess the influence of birth preparedness practices and decision-making and assistance by SBAs among women in south-western Uganda