The Cost of Uncertainty in Curing Epidemics

Motivated by the study of controlling (curing) epidemics, we consider the spread of an SI process on a known graph, where we have a limited budget to use to transition infected nodes back to the susceptible state (i.e., to cure nodes). Recent work has demonstrated that under perfect and instantaneous information (which nodes are/are not infected), the budget required for curing a graph precisely depends on a combinatorial property called the CutWidth. We show that this assumption is in fact necessary: even a minor degradation of perfect information, e.g., a diagnostic test that is 99% accurate, drastically alters the landscape. Infections that could previously be cured in sublinear time now may require exponential time, or orderwise larger budget to cure. The crux of the issue comes down to a tension not present in the full information case: if a node is suspected (but not certain) to be infected, do we risk wasting our budget to try to cure an uninfected node, or increase our certainty by longer observation, at the risk that the infection spreads further? Our results present fundamental, algorithm-independent bounds that tradeoff budget required vs. uncertainty.Comment: 35 pages, 3 figure

Mode of Delivery Decisions Among HIV-infected Mothers at an Urban Maternity Hospital in Nairobi, Kenya

Purpose: The objectives of this study are to describe mode of delivery decision making among HIV positive women, understand patient knowledge and attitudes regarding elective cesarean section (ECS) for prevention of mother-to-child transmission of HIV (PMTCT), and in turn quantify the use of ECS for PMTCT at an urban Kenyan maternity hospital. Methods: This is a descriptive cross-sectional study involving the survey of postpartum HIV-infected women delivering at Pumwani Maternity Hospital (PMH) in Nairobi, Kenya. Each participant was interviewed using a standardized questionnaire. Results: 250 women participated in this study over the course of three months. The rate of delivery by ECS for PMTCT was 4.0% (10/250), though 13.6% (34/250) planned this mode of delivery. Planning ECS was positively correlated with higher education levels (OR: 1.46; 95% CI: 1.09-1.94, p=0.028) and markers of higher socio-economic status including having a private toilet (OR: 2.89; 95% CI: 1.43-3.84, p=0.002) and living in a home with greater than one room (OR: 2.89; 95% CI: 1.07-7.80, p=0.033). The strongest correlates of ECS planning included having a surgical history (OR=5.86, 95% CI: 2.92-11.77, p\u3c0.001), attending clinic at PMH (OR=7.85, 95% CI: 4.63-13.30, p\u3c0.001), and knowledge of ECS (OR=24.50, 95% CI: 8.10-93.35, p\u3c0.001). Patient education regarding ECS for PMTCT was limited, and 64% (160/250) of participants had never heard of this PMTCT intervention. Most often cited concerns regarding cesarean section included increased recovery time (66.3%), minor complications (55.4%), and risk of death (48.7%). Post-counseling, 48.0% (120/250) of participants would choose elective cesarean section if offered, while 67.6% (169/250) would opt for this mode of delivery if the cost of ECS was the same as vaginal delivery. Correlates of ECS acceptability included high socioeconomic status (e.g. secondary education OR=1.64, 95% CI: 1.25-2.15, p\u3c0.001; ability to pay for delivery OR=1.40, 95% CI: 1.12-1.76, p=0.003), surgical history (OR=2.79, 95% CI: 1.21-6.43, p=0.011), and attendance at PMH antenatal clinic (OR=3.03, 95% CI: 1.54-5.98 p=0.001). Conclusions: Patient knowledge and uptake of ECS for PMTCT is limited at PMH. Although women are aware of the dangers of ECS, post-counseling acceptability of ECS, especially if the burden of cost is removed, is high

Achieving Sustainable Mobility. The Discontinuation of the Socio-Technical Regime of Automobility

So far, research on sustainable transitions has predominantly focussed on the management of innovation processes and mostly neglected that political decision-making has also to consider the discontinuation of the established socio-technical regime. We will present a case study on the automobility regime as an example of discontinuation governance “in the making”. Analysing policies and actor constellations on local, national, and supranational levels, we try to figure out strategies and measures that have been applied to (politically) challenge the automobility regime. Additionally, we propose combining three analytical models in order to grasp these developments, namely the multi-level perspective (MLP), the multi-level governance (MLG) and actor-centred approaches

Breath‐by‐breath oxygen uptake during running: Effects of different calculation algorithms

New Findings What is the central question of this study? Breath‐by‐breath gas exchange analysis during treadmill exercise can be disturbed by different breathing patterns depending on cadence, and the flow sensor might be subjected to variable mechanical stress. It is still unclear whether the outcomes of the gas exchange algorithms can be affected by running at different speeds. What is the main finding and its importance? Practically, the three investigated breath‐by‐breath algorithms ('Wessel', 'expiration‐only' and 'independent breath') provided similar average gas exchange values for steady‐state conditions. The 'independent breath' algorithm showed the lowest breath‐by‐breath fluctuations in the gas exchange data compared with the other investigated algorithms, both at steady state and during incremental exercise. AbstractRecently, a new breath‐by‐breath gas exchange calculation algorithm (called 'independent breath') was proposed. In the present work, we aimed to compare the breath‐by‐breath O2 uptake () values assessed in healthy subjects undergoing a running protocol, as calculated applying the 'independent breath' algorithm or two other commonly used algorithms. The traces of respiratory flow, O2 and CO2 fractions, used by the calculation algorithms, were acquired at the mouth on 17 volunteers at rest, during running on a treadmill at 6.5 and 9.5 km h−1, and thereafter up to volitional fatigue. Within‐subject averages and standard deviations of breath‐by‐breath were calculated for steady‐state conditions; the data of the incremental phase were analysed by means of linear regression, and their root mean square was assumed to be an index of the breath‐by‐breath fluctuations. The average values obtained with the different algorithms were significantly different (P < 0.001); nevertheless, from a practical point of view the difference could be considered 'small' in all the investigated conditions (effect size <0.3). The standard deviations were significantly lower for the 'independent breath' algorithm (post hoc contrasts, P < 0.001), and the slopes of the relationships with the corresponding data yielded by the other algorithms were <0.70. The root mean squares of the linear regressions calculated for the incremental phase were also significantly lower for the 'independent breath' algorithm, and the slopes of the regression lines with the corresponding values obtained with the other algorithms were <0.84. In conclusion, the 'independent breath' algorithm yielded the least breath‐by‐breath O2 uptake fluctuation, both during steady‐state exercise and during incremental running