Alternative Representations in Algebraic Problem Solving: When are Graphs Better Than Equations?

Successful algebraic problem solving entails adaptability of solution methods using different representations. Prior research has suggested that students are more likely to prefer symbolic solution methods (equations) over graphical ones, even when graphical methods should be more efficient. However, this research has not tested how representation format might affect solution success, and whether the efficiency of solution varies depending on the nature of the problem solving task. This study addressed the question of whether symbolic or graphical representation format provides different affordances with respect to two different types of problems: computation and interpretation. Graphical representation was found to facilitate problem solving among college students, and problems that required the comparison of slopes were more difficult when presented in a symbolic format than in graphical format

Hindsight Bias in Insight and Mathematical Problem Solving: Evidence of Different Reconstruction Mechanisms for Metacognitive Versus Situational Judgments

This article presents two experiments that used insight and mathematical problems to investigate whether different factors would affect hindsight bias on metacognitive and situational judgments. In both studies, participants initially rated their likelihood of solving each problem within a certain amount of time (metacognitive judgments) and rated the importance of each component of the problem for finding the solution (situational judgments). Next, participants attempted to solve each problem. In Experiment 1, all participants were given solution feedback information, but in Experiment 2, participants were not given any solution feedback. After 1 week, participants were asked to recall their original judgments. Hindsight bias was assessed by comparing the initial with the final ratings. Insight problems and math problems showed different patterns of hindsight bias effects on the metacognitive and situational judgments. The results suggest that two competing models of hindsight effects are actually complementary explanations for judgment reconstruction on different types of judgment tasks

A Novel Sequence-Based Antigenic Distance Measure for H1N1, with Application to Vaccine Effectiveness and the Selection of Vaccine Strains

H1N1 influenza causes substantial seasonal illness and was the subtype of the 2009 influenza pandemic. Precise measures of antigenic distance between the vaccine and circulating virus strains help researchers design influenza vaccines with high vaccine effectiveness. We here introduce a sequence-based method to predict vaccine effectiveness in humans. Historical epidemiological data show that this sequence-based method is as predictive of vaccine effectiveness as hemagglutination inhibition (HI) assay data from ferret animal model studies. Interestingly, the expected vaccine effectiveness is greater against H1N1 than H3N2, suggesting a stronger immune response against H1N1 than H3N2. The evolution rate of hemagglutinin in H1N1 is also shown to be greater than that in H3N2, presumably due to greater immune selection pressure.Comment: 26 pages, 7 figures, 2 tables, supplemen

Apollo experience report: Development of guidance targeting techniques for the command module and launch vehicle

The development of the guidance targeting techniques for the Apollo command module and launch vehicle is discussed for four types of maneuvers: (1) translunar injection, (2) translunar midcourse, (3) lunar orbit insertion, and (4) return to earth. The development of real-time targeting programs for these maneuvers and the targeting procedures represented are discussed. The material is intended to convey historically the development of the targeting techniques required to meet the defined target objectives and to illustrate the solutions to problems encountered during that development

Astronomy in the Cloud: Using MapReduce for Image Coaddition

In the coming decade, astronomical surveys of the sky will generate tens of terabytes of images and detect hundreds of millions of sources every night. The study of these sources will involve computation challenges such as anomaly detection and classification, and moving object tracking. Since such studies benefit from the highest quality data, methods such as image coaddition (stacking) will be a critical preprocessing step prior to scientific investigation. With a requirement that these images be analyzed on a nightly basis to identify moving sources or transient objects, these data streams present many computational challenges. Given the quantity of data involved, the computational load of these problems can only be addressed by distributing the workload over a large number of nodes. However, the high data throughput demanded by these applications may present scalability challenges for certain storage architectures. One scalable data-processing method that has emerged in recent years is MapReduce, and in this paper we focus on its popular open-source implementation called Hadoop. In the Hadoop framework, the data is partitioned among storage attached directly to worker nodes, and the processing workload is scheduled in parallel on the nodes that contain the required input data. A further motivation for using Hadoop is that it allows us to exploit cloud computing resources, e.g., Amazon's EC2. We report on our experience implementing a scalable image-processing pipeline for the SDSS imaging database using Hadoop. This multi-terabyte imaging dataset provides a good testbed for algorithm development since its scope and structure approximate future surveys. First, we describe MapReduce and how we adapted image coaddition to the MapReduce framework. Then we describe a number of optimizations to our basic approach and report experimental results comparing their performance.Comment: 31 pages, 11 figures, 2 table

Efficacy of Targeted Mist-Netting to Capture Northern Bobwhites During the Non-Breeding Season in Ohio

Baited funnel traps and nightlighting are well established northern bobwhite (Colinus virginianus) capture techniques, but their use is not always appropriate, particularly on private land where cooperating landowners may place constraints on research activities. Alternative capture techniques may be more effective under conditions considered to be unfavorable for established techniques (e.g., periods with abundant natural food). Targeted mist-netting, where mist nets are erected near the known location of specific individuals, has been used to capture gallinaceous species and may be an effective alternative to established bobwhite capture techniques. We evaluated the effectiveness of using targeted mist-netting to capture bobwhites during the non-breeding season in Ohio. We tested for differences in survival and age and sex ratios of individuals captured with targeted netting and baited funnel traps. We captured 257 individuals with targeted netting during 1 October-28 February 2009–2011 and concurrently captured 253 individuals with baited funnel traps. There was a short-term influence of capture and handling, but there was no significant difference in post-capture survival of bobwhites captured with targeted netting or trapping. Capture rates of age and sex classes were similar (P 1⁄4 0.488 and P 1⁄4 0.973, respectively) between targeted netting and trapping. Body mass of bobwhites captured by targeted netting was less than that of bobwhites captured by trapping (P 1⁄4 0.009) suggesting that netting may provide more accurate estimates of body mass. We used targeted netting to capture bobwhites in a variety of situations where use of funnel traps was ineffective or problematic. Targeted netting was effective and often more compatible with constraints of working on private land than established capture techniques

Influenza vaccination during pregnancy: A qualitative study of the knowledge, attitudes, beliefs, and practices of general practitioners in Central and South-Western Sydney

Background: Pregnant women have an increased risk of influenza complications. Influenza vaccination during pregnancy is safe and effective, however coverage in Australia is less than 40%. Pregnant women who receive a recommendation for influenza vaccination from a health care provider are more likely to receive it, however the perspectives of Australian general practitioners has not previously been reported. The aim of the study was to investigate the knowledge, attitudes, beliefs, and practices of general practitioners practicing in South-Western Sydney, Australia towards influenza vaccination during pregnancy. Methods. A qualitative descriptive study was conducted, with semi-structured interviews completed with seventeen general practitioners in October 2012. A thematic analysis was undertaken by four researchers, and transcripts were analysed using N-Vivo software according to agreed codes. Results: One-third of the general practitioners interviewed did not consider influenza during pregnancy to be a serious risk for the mother or the baby. The majority of the general practitioners were aware of the government recommendations for influenza vaccination during pregnancy, but few general practitioners were confident of their knowledge about the vaccine and most felt they needed more information. More than half the general practitioners had significant concerns about the safety of influenza vaccination during pregnancy. Their practices in the provision of the vaccine were related to their perception of risk of influenza during pregnancy and their confidence about the safety of the vaccine. While two-thirds reported that they are recommending influenza vaccination to their pregnant patients, many were adopting principles of patient-informed choice in their approach and encouraged women to decide for themselves whether they would receive the vaccine. Conclusions: General practitioners have varied knowledge, attitudes, and beliefs about influenza vaccination during pregnancy, which influence their practices. Addressing these could have a significant impact on improving vaccine uptake during pregnancy. © 2014 Maher et al.; licensee BioMed Central Ltd

Ten myths about character, virtue and virtue education – plus three well-founded misgivings

Initiatives to cultivate character and virtue in moral education at school continue to provoke sceptical responses. Most of those echo familiar misgivings about the notions of character, virtue and education in virtue – as unclear, redundant, old-fashioned, religious, paternalistic, anti-democratic, conservative, individualistic, relative and situation dependent. I expose those misgivings as ‘myths’, while at the same time acknowledging three better-founded historical, methodological and practical concerns about the notions in question

Population Cancer Risks Associated with Coal Mining: A Systematic Review

BACKGROUND: Coal is produced across 25 states and provides 42% of US energy. With production expected to increase 7.6% by 2035, proximate populations remain at risk of exposure to carcinogenic coal products such as silica dust and organic compounds. It is unclear if population exposure is associated with increased risk, or even which cancers have been studied in this regard. METHODS: We performed a systematic review of English-language manuscripts published since 1980 to determine if coal mining exposure was associated with increased cancer risk (incidence and mortality). RESULTS: Of 34 studies identified, 27 studied coal mining as an occupational exposure (coal miner cohort or as a retrospective risk factor) but only seven explored health effects in surrounding populations. Overall, risk assessments were reported for 20 cancer site categories, but their results and frequency varied considerably. Incidence and mortality risk assessments were: negative (no increase) for 12 sites; positive for 1 site; and discordant for 7 sites (e.g. lung, gastric). However, 10 sites had only a single study reporting incidence risk (4 sites had none), and 11 sites had only a single study reporting mortality risk (2 sites had none). The ecological study data were particularly meager, reporting assessments for only 9 sites. While mortality assessments were reported for each, 6 had only a single report and only 2 sites had reported incidence assessments. CONCLUSIONS: The reported assessments are too meager, and at times contradictory, to make definitive conclusions about population cancer risk due to coal mining. However, the preponderance of this and other data support many of Hill\u27s criteria for causation. The paucity of data regarding population exposure and risk, the widespread geographical extent of coal mining activity, and the continuing importance of coal for US energy, warrant further studies of population exposure and risk