Far From Threshold Buckling Analysis of Thin Films

Thin films buckle easily and form wrinkled states in regions of well defined size. The extent of a wrinkled region is typically assumed to reflect the zone of in-plane compressive stresses prior to buckling, but recent experiments on ultrathin sheets have shown that wrinkling patterns are significantly longer and follow different scaling laws than those predicted by standard buckling theory. Here we focus on a simple setup to show the striking differences between near-threshold buckling and the analysis of wrinkle patterns in very thin films, which are typically far from threshold.Comment: 4 page

Casimir Effects in Renormalizable Quantum Field Theories

We review the framework we and our collaborators have developed for the study of one-loop quantum corrections to extended field configurations in renormalizable quantum field theories. We work in the continuum, transforming the standard Casimir sum over modes into a sum over bound states and an integral over scattering states weighted by the density of states. We express the density of states in terms of phase shifts, allowing us to extract divergences by identifying Born approximations to the phase shifts with low order Feynman diagrams. Once isolated in Feynman diagrams, the divergences are canceled against standard counterterms. Thus regulated, the Casimir sum is highly convergent and amenable to numerical computation. Our methods have numerous applications to the theory of solitons, membranes, and quantum field theories in strong external fields or subject to boundary conditions.Comment: 27 pp., 11 EPS figures, LaTeX using ijmpa1.sty; email correspondence to R.L. Jaffe ; based on talks presented by the authors at the 5th workshop `QFTEX', Leipzig, September 200

The Influence of Apparent Temperature on Mortality in the Kintampo Health and Demographic Surveillance Area in the Middle Belt of Ghana: A Retrospective Time-Series Analysis.

Globally, studies have shown that diurnal changes in weather conditions and extreme weather events have a profound effect on mortality. Here, we assessed the effect of apparent temperature on all-cause mortality and the modifying effect of sex on the apparent temperature-mortality relationship using mortality and weather data archived over an eleven-year period. An overdispersed Poisson regression and distributed lag nonlinear models were used for this analysis. With these models, we analysed the relative risk of mortality at different temperature values over a 10-day lag period. By and large, we observed a nonlinear association between mean daily apparent temperature and all-cause mortality. An assessment of different temperature values over a 10-day lag period showed an increased risk of death at the lowest apparent temperature (18°C) from lag 2 to 4 with the highest relative risk of mortality (RR = 1.61, 95% CI: 1.2, 2.15, p value = 0.001) occurring three days after exposure. The relative risk of death also varied between males (RR = 0.31, 95% CI: 0.10, 0.94) and females (RR = 4.88, 95% CI: 1.40, 16.99) by apparent temperature and lag. On the whole, males are sensitive to both temperature extremes whilst females are more vulnerable to low temperature-related mortality. Accordingly, our findings could inform efforts at reducing temperature-related mortality in this context and other settings with similar environmental and demographic characteristics

Hepatitis C viral evolution in genotype 1 treatment-naïve and treatment-experienced patients receiving telaprevir-based therapy in clinical trials

Background: In patients with genotype 1 chronic hepatitis C infection, telaprevir (TVR) in combination with peginterferon and ribavirin (PR) significantly increased sustained virologic response (SVR) rates compared with PR alone. However, genotypic changes could be observed in TVR-treated patients who did not achieve an SVR. Methods: Population sequence analysis of the NS3•4A region was performed in patients who did not achieve SVR with TVR-based treatment. Results: Resistant variants were observed after treatment with a telaprevir-based regimen in 12% of treatment-naïve patients (ADVANCE; T12PR arm), 6% of prior relapsers, 24% of prior partial responders, and 51% of prior null responder patients (REALIZE, T12PR48 arms). NS3 protease variants V36M, R155K, and V36M+R155K emerged frequently in patients with genotype 1a and V36A, T54A, and A156S/T in patients with genotype 1b. Lower-level resistance to telaprevir was conferred by V36A/M, T54A/S, R155K/T, and A156S variants; and higher-level resistance to telaprevir was conferred by A156T and V36M+R155K variants. Virologic failure during telaprevir treatment was more common in patients with genotype 1a and in prior PR nonresponder patients and was associated with higher-level telaprevir-resistant variants. Relapse was usually associated with wild-type or lower-level resistant variants. After treatment, viral populations were wild-type with a median time of 10 months for genotype 1a and 3 weeks for genotype 1b patients. Conclusions: A consistent, subtype-dependent resistance profile was observed in patients who did not achieve an SVR with telaprevir-based treatment. The primary role of TVR is to inhibit wild-type virus and variants with lower-levels of resistance to telaprevir. The complementary role of PR is to clear any remaining telaprevir-resistant variants, especially higher-level telaprevir-resistant variants. Resistant variants are detectable in most patients who fail to achieve SVR, but their levels decline over time after treatment

Clustering of childhood mortality in the Kintampo Health and Demographic Surveillance System in Ghana

Background: Childhood mortality in Ghana has generally declined in the last four decades. However, estimates tend to conceal substantial variability among regions and districts. The lack of population-based data in Ghana, as in other less developed countries, has hindered the development of effective programmes targeted specifically at clusters where mortality levels are significantly higher. Objective: This paper seeks to test for the existence of statistically significant clusters of childhood mortality within the Kintampo Health and Demographic Surveillance System (KHDSS) between 2005 and 2007. Design: In this study, mortality rates were generated using mortality data extracted from the health and demographic surveillance database of the KHDSS and exported into STATA. The spatial and spatio-temporal scan statistic by Kulldorff was used to identify significant clusters of childhood mortality within the KHDSS. Results: A significant cluster of villages with high under-five mortality in the south-eastern part of the KHDSS in 2006 was identified. This is a remote location where poverty levels are relatively higher, health facilities are more sparse and these are compounded by poor transport services in case of emergencies. Conclusion: This study highlights the potential of the surveillance platform to demonstrate the spatial dimensions of childhood mortality clustering. It is apparent, though, that further studies need to be carried out in order to explore the underlying risk factors for potential mortality clusters that could emerge later

Community perceptions of malaria and malaria treatment behaviour in a rural district of Ghana: implications for artemisinin combination therapy

<p>Abstract</p> <p>Background</p> <p>Artesunate-amodiaquine (AS-AQ) was introduced in Ghana as the first line drug for treatment of uncomplicated malaria in 2004. We report the perceptions of malaria and malaria treatment behaviour, the community awareness of and perceptions about AS-AQ two years after the introduction of this ACT treatment for malaria.</p> <p>Methods</p> <p>Two surveys were conducted; a cross-sectional survey of 729 randomly selected household heads (urban-362, rural-367) and 282 women with children < 5 years (urban-121, rural-161) was conducted in 2006. A district wide survey was conducted in 2007 to assess awareness of AS-AQ. These were complemented with twenty-eight focus group discussions (FGDs) and 16 key informant interviews (KII) among community members and major stakeholders in the health care delivery services. All nine (9) health facilities and five (5) purposively selected drug stores were audited in order to identify commonly used anti-malarials in the study area at the time of the survey.</p> <p>Results</p> <p>Majority of respondents ( > 75%) in the sampled survey mentioned mosquito bites as the cause of malaria. Other causes mentioned include environmental factors (e.g. dirty surroundings) and standing in the sun. Close to 60% of the household heads and 40% of the care-givers interviewed did not know about AS-AQ. The community respondents who knew about and had ever taken AS-AQ perceived it to be a good drug; although they mentioned they had experienced some side effects including headaches and body weakness. Co-blistered AS-AQ was available in all the government health facilities in the study area. Different formulations of ACTs were however found in urban chemical shops but not in rural chemical stores where monotherapy antimalarials were predominant.</p> <p>Conclusion</p> <p>The knowledge of fever as a symptom of malaria is high among the study population. The awareness of AS-AQ therapy and its side-effect was low in the study area. Community education and sensitization, targeting all categories of the population, has to be intensified to ensure an efficient implementation process.</p

Food scares in an uncertain world

This is the accepted version of the following article: Food scares in an uncertain world. Journal of the European Economic Association, Volume 11, Issue 6, pages 1432–1456, December 2013, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/jeea.12057/abstrac

Food scares in an uncertain world

This is the accepted version of the following article: Food scares in an uncertain world. Journal of the European Economic Association, Volume 11, Issue 6, pages 1432–1456, December 2013, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/jeea.12057/abstrac

Family Planning Awareness, Perceptions and Practice among Community Members in the Kintampo Districts of Ghana

Family planning is known to prevent maternal deaths, but some social norms, limited supplies and inconsistent use makes this difficult to achieve in most low- and middle-income countries. In spite of the high fertility levels in most sub-Saharan African countries and the potential economic benefits of family planning, its patronage remains very low in the sub-region. This study was with the objective of identifying the levels of awareness, utilization, access to and perceptions about family planning and contraception. A cross-sectional study design was used for the study, with data collected from multiple sources using both quantitative and qualitative approaches. Relevant findings included a marked disconnect between family planning/contraceptive knowledge and use. The pills and injectables were the most frequently used, but females in the study population poorly patronised emergency contraception. Supplies of most family planning methods were found to be health facility based, requiring clients to have to necessarily go there for services. Some respondents harboured perceptions that family planning was the responsibility of females alone and that it fuelled promiscuity among female users. Recommendations made include ensuring that health facilities had adequate staff and expertise to provide facility-based family planning services and also to disabuse the minds of community members of the negative perceptions towards family planning

Intermittent preventive treatment of pregnant women in Kintampo area of Ghana with sulphadoxine-pyrimethamine (SP): trends spanning 2011 and 2015.

OBJECTIVE: In Ghana, intermittent preventive treatment during pregnancy with sulphadoxine-pyrimethamine (IPTp-SP) is recommended for the prevention of malaria-related adverse outcomes. This study demonstrates the coverage of IPTp-SP use among pregnant women over a period (2011-2015) and the impact of various sociodemographic groups on the uptake of IPTp-SP. DESIGN: Retrospective analysis using data from all pregnant women in the Kintampo Health and Demographic Surveillance System area on the uptake of IPTp-SP. SETTING: Kintampo North Municipality and Kintampo South District of Ghana. PARTICIPANTS: All pregnant women in the Kintampo Health and Demographic Surveillance System area. PRIMARY AND SECONDARY OUTCOME MEASURES: The number of doses of IPTp-SP taken by pregnant women were examined. Logistic regression was used to assess the determinant of uptake of IPTp-SP while adjusting for within-subject correlation from women with multiple pregnancies. RESULTS: Data from 2011 to 2015 with a total of 17 484 pregnant women were used. The coverage of the recommended three or more doses of IPTp-SP among all pregnant women was 40.6%, 44.0%, 45.9%, 20.9% and 32.4% in 2011, 2012, 2013, 2014 and 2015, respectively. In the adjusted analysis, age, household size, education, religion, number of antenatal care visits, ethnicity, marital status, wealth index and place of residence were significantly associated with the uptake of three or more doses of IPTp-SP. Having middle school education or higher, aged 20 years and above, visiting antenatal care five times or more (OR 2.83, 95% CI 2.64 to 3.03), being married (OR 1.10, 95% CI 1.02 to 1.19) and those in higher wealth quintiles were significantly more likely to take three or more doses of IPTp-SP. CONCLUSION: The uptake of the recommended three or more doses of IPTp-SP is low in the study area. We recommend a community-based approach to identify women during early pregnancy and to administer IPTp-SP