Competing Ordered Phases in URu2Si2: Hydrostatic Pressure and Re-substitution

A persistent kink in the pressure dependence of the \hidden order" (HO) transition temperature of URu2-xRexSi2 is observed at a critical pressure Pc=15 kbar for 0 < x < 0.08. In URu2Si2, the kink at Pc is accompanied by the destruction of superconductivity; a change in the magnitude of a spin excitation gap, determined from electrical resistivity measurements; and a complete gapping of a portion of the Fermi surface (FS), inferred from a change in scattering and the competition between the HO state and superconductivity for FS fraction

Electron propagation in crossed magnetic and electric fields

Laser-atom interaction can be an efficient mechanism for the production of coherent electrons. We analyze the dynamics of monoenergetic electrons in the presence of uniform, perpendicular magnetic and electric fields. The Green function technique is used to derive analytic results for the field--induced quantum mechanical drift motion of i) single electrons and ii) a dilute Fermi gas of electrons. The method yields the drift current and, at the same time it allows us to quantitatively establish the broadening of the (magnetic) Landau levels due to the electric field: Level number k is split into k+1 sublevels that render the $k$th oscillator eigenstate in energy space. Adjacent Landau levels will overlap if the electric field exceeds a critical strength. Our observations are relevant for quantum Hall configurations whenever electric field effects should be taken into account.Comment: 11 pages, 2 figures, submitte

The effect of malaria control on <i>Plasmodium falciparum</i> in Africa between 2000 and 2015

Since the year 2000, a concerted campaign against malaria has led to unprecedented levels of intervention coverage across sub-Saharan Africa. Understanding the effect of this control effort is vital to inform future control planning. However, the effect of malaria interventions across the varied epidemiological settings of Africa remains poorly understood owing to the absence of reliable surveillance data and the simplistic approaches underlying current disease estimates. Here we link a large database of malaria field surveys with detailed reconstructions of changing intervention coverage to directly evaluate trends from 2000 to 2015, and quantify the attributable effect of malaria disease control efforts. We found that Plasmodium falciparum infection prevalence in endemic Africa halved and the incidence of clinical disease fell by 40% between 2000 and 2015. We estimate that interventions have averted 663 (542-753 credible interval) million clinical cases since 2000. Insecticide-treated nets, the most widespread intervention, were by far the largest contributor (68% of cases averted). Although still below target levels, current malaria interventions have substantially reduced malaria disease incidence across the continent. Increasing access to these interventions, and maintaining their effectiveness in the face of insecticide and drug resistance, should form a cornerstone of post-2015 control strategies.</p

Costs and cost-effectiveness of malaria control interventions - a systematic review

<p>Abstract</p> <p>Background</p> <p>The control and elimination of malaria requires expanded coverage of and access to effective malaria control interventions such as insecticide-treated nets (ITNs), indoor residual spraying (IRS), intermittent preventive treatment (IPT), diagnostic testing and appropriate treatment. Decisions on how to scale up the coverage of these interventions need to be based on evidence of programme effectiveness, equity and cost-effectiveness.</p> <p>Methods</p> <p>A systematic review of the published literature on the costs and cost-effectiveness of malaria interventions was undertaken. All costs and cost-effectiveness ratios were inflated to 2009 USD to allow comparison of the costs and benefits of several different interventions through various delivery channels, across different geographical regions and from varying costing perspectives.</p> <p>Results</p> <p>Fifty-five studies of the costs and forty three studies of the cost-effectiveness of malaria interventions were identified, 78% of which were undertaken in sub-Saharan Africa, 18% in Asia and 4% in South America. The median financial cost of protecting one person for one year was $2.20 (range$0.88-$9.54) for ITNs,$6.70 (range $2.22-$12.85) for IRS, $0.60 (range$0.48-$1.08) for IPT in infants,$4.03 (range $1.25-$11.80) for IPT in children, and $2.06 (range$0.47-$3.36) for IPT in pregnant women. The median financial cost of diagnosing a case of malaria was$4.32 (range $0.34-$9.34). The median financial cost of treating an episode of uncomplicated malaria was $5.84 (range$2.36-$23.65) and the median financial cost of treating an episode of severe malaria was$30.26 (range $15.64-$137.87). Economies of scale were observed in the implementation of ITNs, IRS and IPT, with lower unit costs reported in studies with larger numbers of beneficiaries. From a provider perspective, the median incremental cost effectiveness ratio per disability adjusted life year averted was $27 (range$8.15-$110) for ITNs,$143 (range $135-$150) for IRS, and $24 (range$1.08-$44.24) for IPT.</p> <p>Conclusions</p> <p>A transparent evidence base on the costs and cost-effectiveness of malaria control interventions is provided to inform rational resource allocation by donors and domestic health budgets and the selection of optimal packages of interventions by malaria control programmes.</p

Cost analysis of school-based intermittent screening and treatment of malaria in Kenya

<p>Abstract</p> <p>Background</p> <p>The control of malaria in schools is receiving increasing attention, but there remains currently no consensus as to the optimal intervention strategy. This paper analyses the costs of intermittent screening and treatment (IST) of malaria in schools, implemented as part of a cluster-randomized controlled trial on the Kenyan coast.</p> <p>Methods</p> <p>Financial and economic costs were estimated using an ingredients approach whereby all resources required in the delivery of IST are quantified and valued. Sensitivity analysis was conducted to investigate how programme variation affects costs and to identify potential cost savings in the future implementation of IST.</p> <p>Results</p> <p>The estimated financial cost of IST per child screened is US$6.61 (economic cost US$ 6.24). Key contributors to cost were salary costs (36%) and malaria rapid diagnostic tests (RDT) (22%). Almost half (47%) of the intervention cost comprises redeployment of existing resources including health worker time and use of hospital vehicles. Sensitivity analysis identified changes to intervention delivery that can reduce programme costs by 40%, including use of alternative RDTs and removal of supervised treatment. Cost-effectiveness is also likely to be highly sensitive to the proportion of children found to be RDT-positive.</p> <p>Conclusion</p> <p>In the current context, school-based IST is a relatively expensive malaria intervention, but reducing the complexity of delivery can result in considerable savings in the cost of intervention.</p> <p>(Costs are reported in US$ 2010).</p

Who attends antenatal care and expanded programme on immunization services in Chad, Mali and Niger? the implications for insecticide-treated net delivery

UNLABELLED: ABSTRACT: BACKGROUND: Malaria remains one of the largest public health problems facing the developing world. Insecticide-treated nets (ITNs) are an effective intervention against malaria. ITN delivery through routine health services, such as antenatal care (ANC) and childhood vaccination (EPI), is a promising channel of delivery to reach individuals with the highest risk (pregnant women and children under five years old). Decisions on whether to deliver ITNs through both channels depends upon the reach of each of these systems, whether these are independent and the effectiveness and cost effectiveness of each. Predictors of women attending ANC and EPI separately have been studied, but the predictors of those who attend neither service have not been identified. METHODS: Data from Chad, Mali and Niger demographic and health surveys (DHS) were analyzed to determine risk factors for attending neither service. A conceptual framework for preventative health care-seeking behaviour was created to illustrate the hierarchical relationships between the potential risk factors. The independence of attending both ANC and EPI was investigated. A multivariate model of predictors for non-attendance was developed using logistic regression. RESULTS: ANC and EPI attendance were found to be strongly associated in all three countries. However, 47% of mothers in Chad, 12% in Mali and 36% in Niger did not attend either ANC or EPI. Region, mother's education and partner's education were predictors of non-attendance in all three countries. Wealth index, ethnicity, and occupation were associated with non-attendance in Mali and Niger. Other predictors included religion, healthcare autonomy, household size and number of children under five. CONCLUSIONS: Attendance of ANC and EPI are not independent and therefore the majority of pregnant women in these countries will have the opportunity to receive ITNs through both services. Although attendance at ANC and EPI are not independent, delivery through both systems may still add incrementally to delivery through one alone. Therefore, there is potential to increase the proportion of women and children receiving ITNs by delivering through both of these channels. However, modelling is required to determine the level of attendance and incremental potential at which it's cost effective to deliver through both services

Determinants of the Cost-Effectiveness of Intermittent Preventive Treatment for Malaria in Infants and Children

BACKGROUND: Trials of intermittent preventive treatment in infants (IPTi) and children (IPTc) have shown promising results in reducing malaria episodes but with varying efficacy and cost-effectiveness. The effects of different intervention and setting characteristics are not well known. We simulate the effects of the different target age groups and delivery channels, seasonal or year-round delivery, transmission intensity, seasonality, proportions of malaria fevers treated and drug characteristics. METHODS: We use a dynamic, individual-based simulation model of Plasmodium falciparum malaria epidemiology, antimalarial drug action and case management to simulate DALYs averted and the cost per DALY averted by IPTi and IPTc. IPT cost components were estimated from economic studies alongside trials. RESULTS: IPTi and IPTc were predicted to be cost-effective in most of the scenarios modelled. The cost-effectiveness is driven by the impact on DALYs, particularly for IPTc, and the low costs, particularly for IPTi which uses the existing delivery strategy, EPI. Cost-effectiveness was predicted to decrease with low transmission, badly timed seasonal delivery in a seasonal setting, short-acting and more expensive drugs, high frequencies of drug resistance and high levels of treatment of malaria fevers. Seasonal delivery was more cost-effective in seasonal settings, and year-round in constant transmission settings. The difference was more pronounced for IPTc than IPTi due to the different proportions of fixed costs and also different assumed drug spacing during the transmission season. The number of DALYs averted was predicted to decrease as a target five-year age-band for IPTc was shifted from children under 5 years into older ages, except at low transmission intensities. CONCLUSIONS: Modelling can extend the information available by predicting impact and cost-effectiveness for scenarios, for outcomes and for multiple strategies where, for practical reasons, trials cann be carried out. Both IPTi and IPTc are generally cost-effective but could be rendered cost-ineffective by characteristics of the setting, drug or implementatio

"Test and treat" or presumptive treatment for malaria in high transmission situations? A reflection on the latest WHO guidelines

Recent WHO guidelines recommend a universal "test and treat" strategy for malaria, mainly by use of rapid diagnostic test (RDT) in all areas. The evidence for this approach is questioned here as there is a risk of over-reliance on parasitological diagnosis in high transmission situations, which still exist. In such areas, when a patient has fever or other malaria symptoms, the presence of Plasmodium spp neither reliably confirms malaria as the cause of the fever, nor excludes the possibility of other diseases. This is because the patient may be an asymptomatic carrier of malaria parasites and suffer from another disease

Determinants of Use of Insecticide Treated Nets for the Prevention of Malaria in Pregnancy: Jinja, Uganda

One established means of preventing the adverse consequences of malaria during pregnancy is sleeping under an insecticide treated net (ITN) throughout pregnancy. Despite increased access to this intervention over time, consistent ITN use during pregnancy remains relatively uncommon in sub-Saharan Africa.We sought to identify determinants of ITN use during pregnancy. Utilizing a population-based random sample, we interviewed 500 women living in Jinja, Uganda, who had been pregnant in the past year. ITN ownership at the start of pregnancy was reported by 359 women (72%) and 28 women (20%) acquired an ITN after the first trimester of pregnancy. Among 387 ITN owners, 73% reported either always sleeping under the ITN during all trimesters of pregnancy, or after acquiring their net. Owning more than 1 net was slightly associated with always sleeping under an ITN during pregnancy (RR: 1.13; 95% CI: 1.00, 1.28). Women who always slept under an ITN during pregnancy were more likely to be influenced by an advertisement on the radio/poster than being given an ITN free of charge (RR: 1.48; 95% CI: 1.24, 1.76). No differences were found between other socio-demographic factors, pregnancy history, ANC use or socio-cultural factors.While self-reported ITN ownership and use was common throughout pregnancy, we were unable to pinpoint why a sizable fraction of Ugandan women did not always adhere to recommendations for use of an ITN during pregnancy. More data are needed on the capacity of individual households to support the installation of ITNs which may provide insight into interventions targeted at improving the convenience and adherence of daily ITN use

Cost-effectiveness of adding indoor residual spraying to case management in Afghan refugee settlements in Northwest Pakistan during a prolonged malaria epidemic.

INTRODUCTION: Financing of malaria control for displaced populations is limited in scope and duration, making cost-effectiveness analyses relevant but difficult. This study analyses cost-effectiveness of adding prevention through targeted indoor residual spraying (IRS) to case management in Afghan refugee settlements in Pakistan during a prolonged malaria epidemic. METHODS/FINDINGS: An intervention study design was selected, taking a societal perspective. Provider and household costs of vector control and case management were collected from provider records and community survey. Health outcomes (e.g. cases and DALYs averted) were derived and incremental cost-effectiveness ratios (ICERs) for cases prevented and DALYs averted calculated. Population, treatment cost, women's time, days of productivity lost, case fatality rate, cases prevented, and DALY assumptions were tested in sensitivity analysis. Malaria incidence peaked at 44/1,000 population in year 2, declining to 14/1,000 in year 5. In total, 370,000 malaria cases, 80% vivax, were diagnosed and treated and an estimated 67,988 vivax cases and 18,578 falciparum and mixed cases prevented. Mean annual programme cost per capita was US$0.56. The additional cost of including IRS over five years per case prevented was US$39; US$50 for vivax (US$43 in years 1-3, US$80 in years 4-5) and US$182 for falciparum (US$139 in years 1-3 and US$680 in years 4-5). Per DALY averted this was US$266 (US$220 in years 1-3 and US$486 in years 4-5) and thus 'highly cost-effective' or cost-effective using WHO and comparison thresholds. CONCLUSIONS: Adding IRS was cost-effective in this moderate endemicity, low mortality setting. It was more cost-effective when transmission was highest, becoming less so as transmission reduced. Because vivax was three times more common than falciparum and the case fatality rate was low, cost-effectiveness estimations for cases prevented appear reliable and more definitive for vivax malaria