Graphical perception of nonlinear trends: discrimination and extrapolation

This dissertation investigated several factors involved in the perception of nonlinear relationships in time series graphs. To model real-world data sets, the graphed data included different sample sizes and levels of variability, and represented different underlying trends. Graph format was also varied. The purpose of the experiments was to determine how these factors affect both trend discrimination and extrapolation accuracy, with the overall goal of determining what types of graphs are optimal in different situations. In Experiment 1, subjects viewed time series graphs on a computer screen and had to identify the type of trend that was present. Six trends (exponential increasing, asymptotic increasing, linear increasing, exponential decreasing, asymptotic decreasing, and linear decreasing) were presented on four graph types (histogram, line graph, scatter plot, and suspended bar graph). The same stimuli were presented in Experiment 2 and subjects extrapolated future data points by adjusting the position of points on the screen. In Experiment 3, subjects were given feedback on their extrapolations in order to determine if this information would improve their forecasts. Experiment 4 examined discrimination and extrapolation accuracy with dynamic displays that included motion. In all experiments, accuracy was higher when variability was lower and sample size was higher. On discrimination tasks, choice accuracy was higher for nonlinear trends than for linear trends. On extrapolation tasks, in contrast, accuracy was lower when exponential trends were presented, due largely to subjects overestimating the rate of change. In regard to graph format, discrimination accuracy was highest when line graphs were used, but extrapolation accuracy was lowest with line graphs. Thus, the optimal graph format depends on the graphical perception task. Line graphs are optimal for discrimination but other graphical formats lead to higher extrapolation accuracy. Neither feedback not dynamic displays improved accuracy

Implementing an Oral History Unit with 9/10s: An Interdisciplinary Approach

The topic of this independent study is oral history and its interdisciplinary uses in a curriculum. The purpose of the paper is to discuss the various uses of this instructional plan as it explores the themes of diversity and cultural pluralism in the society of the United States of America. The first section of this study is a description of the Manhattan Country School (MCS) as the setting where this unit is currently being taught; and then it will address the developmental and curricular implications of the unit. The child development section will include positions on educational theory from theorists such as Erik Erikson, Jean Piaget, Patricia Minuchin and David Elkind to justify the purpose and value of the study. The activity integrates the theories of these psychologists and requires students at nine and ten to use their social, emotional and cognitive domains to successfully fulfill the projects\u27 guidelines. The process will involve six components that are listed for teachers to review in whole group sessions to insure that students understand the expectations of the activity. After the explanation of the methodology, examples of follow-up activities are discussed to connect the interdisciplinary uses of the oral history unit. The conclusion makes references to literature on oral histories that explain the benefits of such a unit to the school, local, and familial communities. The appendix will provide samples of articles, activity sheets used, and visual aids produced during the oral history project

Study protocol for a randomised controlled trial evaluating the effect of prenatal omega-3 LCPUFA supplementation to reduce the incidence of preterm birth: The ORIP trial

Introduction: Preterm birth accounts for more than 85% of all perinatal complications and deaths. Seventy-five per cent of early preterm births (EPTBs) occur spontaneously and without identifiable risk factors. The need for a broadly applicable, effective strategy for primary prevention is paramount. Secondary outcomes from the docosahexaenoic acid (DHA) to Optimise Mother Infant Outcome trial showed that maternal supplementation until delivery with omega-3 (ω-3) long chain polyunsaturated fatty acid (LCPUFA), predominantly as DHA, resulted in a 50% reduction in the incidence of EPTB and an increase in the incidence of post-term induction or post-term prelabour caesarean section due to extended gestation. We aim to determine the effectiveness of supplementing the maternal diet with ω-3 LCPUFA until 34 weeks’ gestation on the incidence of EPTB. Methods and analysis: This is a multicentre, parallel group, randomised, blinded and controlled trial. Women less than 20 weeks’ gestation with a singleton or multiple pregnancy and able to give informed consent are eligible to participate. Women will be randomised to receive high DHA fish oil capsules or control capsules without DHA. Capsules will be taken from enrolment until 34 weeks’ gestation. The primary outcome is the incidence of EPTB, defined as delivery before 34 completed weeks’ gestation. Key secondary outcomes include length of gestation, incidence of post-term induction or prelabour caesarean section and spontaneous EPTB. The target sample size is 5540 women (2770 per group), which will provide 85% power to detect an absolute reduction in the incidence of preterm birth of 1.16% (from 2.45% to 1.29%) between the DHA and control group (two sided α=0.05). The primary analysis will be based on the intention-to-treat principle. Trial registration number: Australia and New Zealand Clinical Trial Registry Number: 2613001142729; Pre-results

Plasma oxylipins and unesterified precursor fatty acids are altered by DHA supplementation in pregnancy: Can they help predict risk of preterm birth?

Oxidized lipids derived from omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids, collectively known as oxylipins, are bioactive signaling molecules that play diverse roles in human health and disease. Supplementation with n-3 docosahexaenoic acid (DHA) during pregnancy has been reported to decrease the risk of preterm birth in singleton pregnancies, which may be due to effects of DHA supplementation on oxylipins or their precursor n-6 and n-3 fatty acids. There is only limited understanding of the levels and trajectory of changes in plasma oxylipins during pregnancy, effects of DHA supplementation on oxylipins and unesterified fatty acids, and whether and how oxylipins and their unesterified precursor fatty acids influence preterm birth. In the present study we used liquid chromatography-tandem mass spectrometry to profile oxylipins and their precursor fatty acids in the unesterified pool using plasma samples collected from a subset of pregnant Australian women who participated in the ORIP (Omega-3 fats to Reduce the Incidence of Prematurity) study. ORIP is a large randomized controlled trial testing whether daily supplementation with n-3 DHA can reduce the incidence of early preterm birth compared to control. Plasma was collected at study entry (≈pregnancy week 14) and again at ≈week 24, in a subgroup of 48 ORIP participants-12 cases with spontaneous preterm (<37 weeks) birth and 36 matched controls with spontaneous term (≥40 weeks) birth. In the combined preterm and term pregnancies, we observed that in the control group without DHA supplementation unesterified AA and AA-derived oxylipins 12-HETE, 15-HETE and TXB2 declined between weeks 14-24 of pregnancy. Compared to control, DHA supplementation increased unesterified DHA, EPA, and AA, DHA-derived 4-HDHA, 10-HDHA and 19,20-EpDPA, and AA-derived 12-HETE at 24 weeks. In exploratory analysis independent of DHA supplementation, participants with concentrations above the median for 5-lipoxygenase derivatives of AA (5-HETE, Odds Ratio (OR) 8.2; p = 0.014) or DHA (4-HDHA, OR 8.0; p = 0.015) at 14 weeks, or unesterified AA (OR 5.1; p = 0.038) at 24 weeks had higher risk of spontaneous preterm birth. The hypothesis that 5-lipoxygenase-derived oxylipins and unesterified AA could serve as mechanism-based biomarkers predicting spontaneous preterm birth should be evaluated in larger, adequately powered studies