A systemic approach to teaching and learning about electrical cells and circuits using two big ideas of science

Our recent exploration of the ideas of student-teachers about DC electric circuits and electrochemical cells has shown the prevalence of numerous misconceptions previously reported in the physics education and chemistry education literature. Our students have developed their concepts throughout the period from grade 6 to BEd III in two separate streams – one essentially in chemistry and the other in physics – despite the reality that a cell and circuit together constitute a system. The potential benefits of adopting a Systemic Approach supported by two Big Ideas of Science Education in addressing the needs of our future science teachers are explored. A joint physics-chemistry topic devoted to the cell and circuit system in the BEd curriculum is proposed

The systemic approach to teaching and learning chemistry and the big ideas of science education

The systemic approach to teaching and learning chemistry has been implemented and researched for a number of years. There is substantial evidence of learning benefits from its application in the context of specific chemistry topics. In the wider context of science curricula however, the ambition of Fahmy and Lagowski to change curricula from linearity to systemic seems yet to be realized. We suggest that such a change could be initiated by introducing the Big Ideas of Science Education into existing curricula in a systemic manner. We exemplify our proposal with the case of the Grade 7-9 Natural Sciences curriculum in South Africa

Using microscience kits to address a student-teacher misconception in electric circuits: At the interface between chemistry and electricity

A test of education students’ understanding of electric circuits, written before their lectures on the topic began, led to practical work with micro-scale circuit apparatus that was designed to further probe and challenge the students’ misconceptions. Response data from one of the lab pracs revealed one very common misconception, that the current through a component was the cause of the potential difference across it. A practical activity based upon the Volta pile was designed to show that current is not the cause of voltage, and that voltage is to be traced to the chemical reaction inside the cells. While some aspects of the activity were successful in a workshop at 10th ISMC, others were not. Our reflections on the outcome lead us to the conclusion that it is necessary to engage with the chemical events inside the cell, in order to understand how it works. Systems-thinking may be the way forward

Pre-service teachers’ misconceptions about current and potential difference in electric circuits – using microscience kits in a POE activity

Third year BEd students in a Physical Sciences content course answered a questionnaire about basic concepts of electric circuits, prior to attending lectures and practicals on the subject. Several well-known misconceptions were found to be prevalent. This led us to design a PredictObserve-Explain (POE) practical activity, using microscience kits. The results from this activity confirmed the prevalence of misconceptions, but also the reluctance of the student-teachers to change them. Our discussion of one important misconception, namely the confusion between current and potential difference, suggests that treating the cell as simply a store of energy and a source of energy without explanation may be the cause of the confusion. A chemist’s approach to this part of physics could avoid the misconception

Bayesian Optimization for Personalized Dose-Finding Trials with Combination Therapies

Identification of optimal dose combinations in early phase dose-finding trials is challenging, due to the trade-off between precisely estimating the many parameters required to flexibly model the dose-response surface, and the small sample sizes in early phase trials. Existing methods often restrict the search to pre-defined dose combinations, which may fail to identify regions of optimality in the dose combination space. These difficulties are even more pertinent in the context of personalized dose-finding, where patient characteristics are used to identify tailored optimal dose combinations. To overcome these challenges, we propose the use of Bayesian optimization for finding optimal dose combinations in standard ("one size fits all") and personalized multi-agent dose-finding trials. Bayesian optimization is a method for estimating the global optima of expensive-to-evaluate objective functions. The objective function is approximated by a surrogate model, commonly a Gaussian process, paired with a sequential design strategy to select the next point via an acquisition function. This work is motivated by an industry-sponsored problem, where focus is on optimizing a dual-agent therapy in a setting featuring minimal toxicity. To compare the performance of the standard and personalized methods under this setting, simulation studies are performed for a variety of scenarios. Our study concludes that taking a personalized approach is highly beneficial in the presence of heterogeneity.Comment: 26 pages, 4 figures, 1 tabl

Origin of a preferential avulsion node on lowland river deltas

River deltas are built by cycles of lobe growth and abrupt channel shifts, or avulsions, that occur within the backwater zone of coastal rivers. Previous numerical models differ on the origin of backwater‐scaled avulsion nodes and their consistency with experimental data. To unify previous work, we developed a numerical model of delta growth that includes backwater hydrodynamics, river mouth progradation, relative sea level rise, variable flow regimes, and cycles of lobe growth, abandonment, and reoccupation. For parameter space applicable to lowland deltas, we found that flow variability is the primary mechanism to cause persistent avulsion nodes by focusing aggradation within the backwater zone. Backwater‐scaled avulsion nodes also occur under less likely scenarios of initially uniform bed slopes or during rapid relative sea level rise and marine transgression. Our findings suggest that flow variability is a fundamental control on long‐term delta morphodynamics

For richer, for poorer: marriage and casualized sex in East African artisanal mining settlements

Migrants to Tanzania's artisanal gold mining sites seek mineral wealth, which is accompanied by high risks of occupational hazards, economic failure, AIDS and social censure from their home communities. Male miners in these settlements compete to attract newly arrived young women who are perceived to be diverting male material support from older women and children's economic survival. This article explores the dynamics of monogamy, polygamy and promiscuity in the context of rapid occupational change. It shows how a wide spectrum of productive and welfare outcomes is generated through sexual experimentation, which calls into question conventional concepts of prostitution, marriage and gender power relations

Gambling with the future of young people

First paragraph: UK Policy makers addressed two key public health problems last summer: smoking and gambling. Both are quasi-voluntary behaviours, involve powerful vested interests and have serious implications for the future health and well being of young people; but policy on them is going in opposite directions. July’s smokefree legislation was followed in October by a law increasing the legal age of tobacco purchase to 18. This builds on the 2002 Tobacco Advertising and Promotion Act, which removed all tobacco advertising, and the mandating of enhanced health warnings in 2001, which in October 2008 will be further improved by the addition of graphic images. These measures combine with systematic increases in the taxation on tobacco products, NHS countrywide smoking cessation services and multi-component health promotion