Performance and Metacognition in Scientific Reasoning

The aim of this study was to introduce a modified version of the covariation detection task to the meta-reasoning framework. This task has been used to assess scientific reasoning through the evaluation of fictitious experiment outcomes and hypothesis testing. The traditional covariation detection task was modified to include only the magnitude versus ratio-bias. The participants' task was to evaluate the effectiveness of an experimental manipulation in a series of fictitious experiments. Experiment 1 (N = 61) consisted of twenty covariation detection tasks. In half of the tasks, normative and heuristic responses were congruent, and for the other half they were incongruent. Experiment 2 (N = 48) had the same experimental design, however, the fictitious data was modified to increase the relative strength of the normative response. After each trial participants provided a judgment of confidence. Results confirmed that the main manipulation of congruence was successful. Participants were more accurate, faster and more confident in the congruent condition. The manipulation from Experiment 2 had a larger impact on response times than on confidence judgments and accuracy. Correct responses were faster in Experiment 2 when compared to Experiment 1, with higher confidence for correct congruent responses. Analyses by response type revealed large individual differences in the relative strength of the processes which generate normative and biased responses. Participants were faster and more confident when rationalizing in favour of their dominant response while they were slower and less confident when decoupling from that dominant response. The covariation detection task provides new valuable insight into meta-reasoning processes.

Experimental Study of the Cross Flow Turbine

The experimental study was intended to investigate characteristics of the cross flow turbine based to the three models designed on the same runner diameter with different runner length of each. The Flow rates were measured by magnetic flow meter, the forces were detected by using spring balance and turbine speeds were detected by tachometer. The performance characteristics are shown by the relation of Power and efficiency versus jet entry arc, as well as the relation of Power and efficiency versus ratio between diameter and width of runner. The study indicated that the efficiency of the models were slightly difference, the highest efficiency indicated by the turbine with the ratio between length of runner and the diameter of the runner was 2; It was corresponding to the 75 degree entry arc.

Use of Mathematical Modelling Indicates That Patients Treated for Acute Myeloid Leukaemia (AML) Are Undertreated When Ideal Body Weight Is Used to Dose Chemotherapy

Chemotherapy for AML is currently dosed using body surface area (BSA) formulas. For overweight patients (defined as actual body weight >20% that of ideal), calculations based on ideal body weight (IBW) are used in order to limit potential toxicity [1]. However, an analysis of the consequences of this adjustment on leukemic and normal bone marrow hematopoietic (HC) cells hasn't been performed. We have developed a mathematical model to simulate personalized chemotherapy for AML [2,3]. The model is used to predict outcomes with standard 3+10 DA treatment [3 doses of 60mg/m2 daunorubicin (DNR) 1h on days 1-3-5 and 2 pulses a day of cytarabine (Ara-C) 100mg/m2 days 1-10]. In this study, we focus on the impact of using ideal vs actual body weight (ABW) for the calculation of BSA using Mosteller's equation on both leukemic and normal HC based on simulating treatment response with our mathematical model. Data were obtained from patients with AML undergoing standard chemotherapy with DA. Cell cycle kinetics of 12 patients was obtained based on matching the % blasts measured on BM biopsies before chemotherapy start and after recovery, which correlates with total cell number in the cell cycle model. Treatments were then simulated based on drug dosage for IBW and ABW. The outcomes (number of leukemic cells remaining) in both cases are recorded after the resting period (Fig. 1). According to these results, patients with ABW closer to IBW will have the same outcome since the BSA is similar; patients with higher ABW will have a better outcome when the ABW is used for the BSA dose-based chemotherapy calculation compared with the outcome obtained by using the IBW; patients with lower ABW than IBW will have a better outcome compared with that obtained with the IBW drug calculation. Seven additional hypothetical patients were simulated in order to validate the results obtained with actual patients; they all fell within the 95% confidence region of the logarithmic fit observed. In order to determine toxicity, as defined by time to normal cell recovery after chemotherapy, HCs were simulated for all 12 patients on both IBW and ABW dosage schemes (Fig. 2). For most patients, the final HC outcome on the ABW was within 10% of the outcome on the IBW dose. Only for one patient was the outcome using ABW significantly lower (25%) than for that using IBW. Put together with the information from Figure 1, these results suggest that DA chemotherapy based on ABW instead of IBW calculations for patients whose weight is over 20% of IBW have a positive impact on reducing leukemic burden, while not significantly affecting HC recovery. Only for very extreme cases (e.g. P12), is the HC recovery impaired, in which case DA dosage based on IBW instead of ABW is preferable. There is an unmet need to standardise dosing of chemotherapy to achieve the best anti-leukemic effect and to quantify (and limit) potential toxicities. The use of IBW for dosing of chemotherapy in AML patients may result in under-treatment and poorer outcomes. Our model suggests that the use of ABW for dose-determination could improve treatment outcomes in AML in terms of leukaemia cell kill but not at the expense of normal HC recovery, except in extreme cases. Ultimately, the use of mathematical models predicting disease progression and targeted treatment outcomes will be critical to realise the potential of precision medicine for the treatment of AML and other cancers. References 1. Berger, N.A., A time to stop, a time to start: high-dose chemotherapy in overweight and obese patients. Bone Marrow Transplant, 2015. 50 (5): p. 617-8. 2. Panoskaltsis, N., et al., Optimized Patient- and Leukemia-Specific Chemotherapy Protocols For The Treatment Of Acute Myeloid Leukemia. Blood, 2013. 122 (21). 3. Fuentes-Gari, M., et al., A mathematical model of subpopulation kinetics for the deconvolution of leukaemia heterogeneity. Journal of the Royal Society Interface, 2015. 12 (108): p. 20150276. Figure 1. Ratio of predicted leukemic cell outcomes (#leukemic cells remaining) for ABW and IBW, versus ratio of BSA to ideal BSA, after the last resting period for 12 patients, with ABW within 20% or over 20% IBW. Logarithmic fit: y-0.274 ∙ ln(x)+0.9844 (95% confidence regions) Figure 1. Ratio of predicted leukemic cell outcomes (#leukemic cells remaining) for ABW and IBW, versus ratio of BSA to ideal BSA, after the last resting period for 12 patients, with ABW within 20% or over 20% IBW. Logarithmic fit: y-0.274 ∙ ln(x)+0.9844 (95% confidence regions) Figure 2. Ratio of predicted normal HC cell outcomes (#normal cells remaining) for ABW and IBW, versus ratio of BSA to ideal BSA, after the last resting period for 12 patients, with ABW within 20% or over 20% IBW. y=0.7488 ∙ ln(x)+1.0035; (95% confidence regions) Figure 2. Ratio of predicted normal HC cell outcomes (#normal cells remaining) for ABW and IBW, versus ratio of BSA to ideal BSA, after the last resting period for 12 patients, with ABW within 20% or over 20% IBW. y=0.7488 ∙ ln(x)+1.0035; (95% confidence regions) Disclosures No relevant conflicts of interest to declare.

Buried pipeline responses to ground displacements induced by adjacent static pipe bursting

To minimize disruptions of economic and social activities on the ground surface in urban areas, trenchless techniques such as pipe bursting are often considered for underground pipeline construction, rehabilitation, and renewal of existing utility services. Pipe bursting, however, inevitably induces outward displacements of surrounding soil, and subsequently leads to potential damages to adjacent structures and utilities. This paper carries out finite element (FE) analyses to investigate effects of the static pipe bursting–induced ground displacements on adjacent pipelines. In total 760 FE parametric studies are performed to encompass various combinations of ground settlement profiles, pipe dimensions, material properties, and soil properties that are typical of utility pipelines and pipe bursting in urban areas. The FE parametric results are summarized in a dimensionless plot of relative pipe–soil stiffness versus ratio of maximum pipe curvature to maximum ground curvature, which can be used to directly estimate the maximum pipe bending strain and (or) directly evaluate pipeline responses to adjacent pipe bursting. A worked example is provided to illustrate usage of the dimensionless plot. It is further found that the pipe–soil interaction is similar for pipe bursting and tunneling, and the effects of both pipe bursting and tunneling on adjacent pipelines can be assessed using a unified dimensionless plot. Effects of the intersection angle between the pipe bursting centerline and adjacent pipeline are explored. The pipe responses are shown to be underestimated or unconservative when only the perpendicular case is considered in the analysis.

Numerical modeling of tunneling effect on buried pipelines

The underground space in urban areas is frequently congested with utilities, including pipelines and conduits, that are affected by underground construction, e.g., tunneling. This paper carries out finite element (FE) analyses to investigate the effects of tunneling-induced ground movement on pipelines, with special attention to the different soil responses to uplift and downward pipe–soil relative movements. A series of numerical parametric studies with 900 FE simulation runs in total is performed to encompass various combinations of ground settlement profiles, pipe dimensions, material properties, pipe burial depth, and soil properties that are typical for utility pipelines and tunnel construction in urban areas. The results are summarized in a dimensionless plot of relative pipe–soil stiffness versus ratio of maximum pipe curvature to maximum ground curvature, which can be used to directly estimate the maximum pipe bending strain and (or) to directly assess the tunneling-induced risk to pipelines. The FE results and dimensionless plot are validated against field and centrifuge test results reported in the literature. Effect of pipeline orientation with respect to the tunnel centerline is explored. It might be unconservative if design analysis only considers the case that the pipeline is perpendicular to the tunnel centerline.