12 research outputs found
Waste processing facility location problem by stochastic programming: Models and solutions
The paper deals with the so-called waste processing facility location problem (FLP), which asks for establishing a set of operational waste processing units, optimal against the total expected cost. We minimize the waste management (WM) expenditure of the waste producers, which is derived from the related waste processing, transportation, and investment costs. We use a stochastic programming approach in recognition of the inherent uncertainties in this area. Two relevant models are presented and discussed in the paper. Initially, we extend the common transportation network flow model with on-and-off waste-processing capacities in selected nodes, representing the facility location. Subsequently, we model the randomly-varying production of waste by a scenario-based two-stage stochastic integer linear program. Finally, we employ selected pricing ideas from revenue management to model the behavior of the waste producers, who we assume to be environmentally friendly. The modeling ideas are illustrated on an example of limited size solved in GAMS. Computations on larger instances were realized with traditional and heuristic algorithms, implemented within MATLAB. © Springer Nature Switzerland AG 2019
Comparison of diurnal variations, gestational age and gender related differences in fetal heart rate (FHR) parameters between appropriate-for-gestational-age (AGA) and small-for-gestational-age (SGA) fetuses in the home environment
Objective
To assess the influence of gender, time of the day and gestational age on fetal heart rate (FHR) parameters between appropriate-for-gestational-age (AGA) and small-for-gestational age (SGA) fetuses using a portable fetal ECG monitor employed in the home setting.
Methods
We analysed and compared the antenatal FHR data collected in the home setting on 61 healthy pregnant women with singleton pregnancies from 24 weeks gestation. Of the 61 women, 31 had SGA fetuses (estimated fetal weight below the tenth gestational centile) and 30 were pregnant with AGA fetuses. FHR recordings were collected for up to 20 h. Two 90 min intervals were deliberately chosen retrospectively with respect to signal recording quality, one during day-time and one at night-time for comparison.
Results
Overall, success rate of the fetal abdominal ECG in the AGA fetuses was 75.7% compared to 48.6% in the SGA group. Based on randomly selected episodes of heart rate traces where recording quality exceeded 80% we were able to show a marginal difference between day and night-time recordings in AGA vs. SGA fetuses beyond 32 weeks of gestation. A selection bias in terms of covering different representation periods of fetal behavioural states cannot be excluded. In contrast to previous studies, we neither controlled maternal diet and activity nor measured maternal blood hormone and heart rate as all mothers were monitored in the home environment.
Conclusion
Based on clinically unremarkable, but statistically significant differences in the FHR parameters between the AGA and SGA group we suggest that further studies with large sample size are required to assess the clinical value of antenatal fetal ECG monitoring
A Study on Effects of Zinc Supplementation on Growth of School Children in Yasuj
Introduction & Objective: Zinc is an important nutrient which is critical for normal immune function and physical growth. Zinc deficiency seems to be common in developing countries and this makes children in those countries prone to infectious diseases. The aim of This study was to find out the effect of zinc supplementation on growth of school children in Yasuj, in Southwest of Iran.
Materials & Methods: The study was done as a double – blinded clinical trial. Eight hundreds and four school children aged 8-11 were the subjects of this study. Children were randomly assigned to zinc or placebo group to receive daily supplementation of zinc or placebo, in an identical form (syrup) and identical pre-coded containers, 6 days per week, for 7 months. Anthropometric assessment was first performed at the time of enrolment and then monthly. The data were analyzed by standard statistical tests using SPSS software.
Results: Results showed significant weight gain in zinc supplemented group compared with placebo group (1.71± 1.48 VS 0.65 ± 1.98 p<0.0001). Also the mean height gain was significantly higher in zinc supplemented group than placebo group 3.26 ± 1.55 VS 1.65 ± 0.94 p<0.0001).
Conclusion: Zinc supplementation improves children’s growth and measures should be taken to supply this nutrient to the children, particularly where zinc deficiency is common