Influence of Process Parameters on Chlorinated Biocide Decontamination by li-CO2 on Artificially Contaminated Model Materials

ABSTRACT

Previously, heavy use of biocides for the treatment of objects made of organic materials in museum collections (e.g. ethnographic, historical collections) was very common. Now suitable decontamination methods/technologies are being sought. A decontamination treatment by li-CO₂ was optimized that considered the specific requirements of museum objects. The treatment was tested on model materials artificially contaminated with biocide solutions containing dichlorodiphenyltrichloroethane (DDT), pentachlorophenol (PCP), lindane, and permethrin or cypermethrin. High decontamination was achieved for DDT, lindane, PCP, and permethrin on artificially biocide loaded wool and wood model materials. Optimal process parameter settings for li-CO₂ decontamination include a single 30?min cycle for woolen materials and three sequential 30?min cycles each for wood. These methods allow a reduction of at least 90% of all biocides for wool and between 70% and 85% for wood. Decontamination of the latter was more effective for less polar biocides as DDT and permethrin. Despite a significant improvement in decontamination for wood using co-solvents such as acetone, ethanol, and methyl tertiary-butyl ether (MTBE), their use is not recommended due to the increased risk of damage to the objects, in particular if a surface coating is present.     

Rapid Feedback Assessment Methods: Can We Improve Engagement and Preparation for Exams in Large-enrollment Courses?

Scratch-off immediate feedback assessment technique (IF-AT) forms and classroom response systems (clickers) can increase student engagement and interaction and help students prepare for exams by indicating the type and level of questions they will encounter. We used the IF-AT throughout the semester in three sections of a lower-division biology class; in two, students worked on IF-AT questions in small permanent groups, and in one, students alternated between IF-AT and clickers each week. At the end of the semester, students answered surveys about instant feedback techniques. Students appreciated prompt feedback on their understanding of course material, enjoyed the group interaction and opportunities to learn from each other, and continued to have positive perceptions of instant feedback activities and to take them seriously throughout the semester. While appreciating the versatility of clicker questions, we find that the ease of use, low cost, effectiveness, and improved classroom climate of the IF-AT method are particularly commendable.     

Middle School Student Knowledge of and Attitudes Toward Synthetic Biology

Journal of Science Education and Technology - Synthetic biology is a field that leverages design, biology, engineering, and computation to genetically engineer organisms to make usable products...     

Access to higher education in South Africa: expanding capabilities in and through an undergraduate photovoice project

ABSTRACT

There is a gap in research on access to universities in South Africa. The research that exists focuses on quantitative methodologies, although some qualitative studies are now emerging. These research methodologies, although necessary and substantial for the development of equity measures and policies, might be less successful in their impact on the local context, on research participants and in expanding what counts as knowledge in the university. In this paper, participatory research, which has not been used to research access, is explored. The paper seeks to go beyond the instrumentalization of research participants – especially those from low-income households – highlighting the potential of using multi-strategy research, in which participatory elements are included as a way to foster both participants’ human development and local impact. Drawing on a research project on access to higher education in South Africa, the paper demonstrates that by including participatory elements (in this case photovoice) has the potential to operationalize Appadurai’s notion of the ‘right to research’ among undergraduates. Using data, including processes, observations, workshops, interviews, and visual narratives from a participatory photovoice project, the findings highlight how methodological plurality creates space for locally and relevant knowledge production, challenging epistemic barriers and fostering human development among the research participants.     

Thinking Counterfactually Supports Children’s Evidence Evaluation in Causal Learning

Often, the evidence we observe is consistent with more than one explanation. How do learners discriminate among candidate causes? The current studies examine whether counterfactuals help 5-year olds (N = 120) select between competing hypotheses and compares the effectiveness of these prompts to a related scaffold. In Experiment 1, counterfactuals support evidence evaluation, leading children to privilege and extend the cause that accounted for more data. In Experiment 2, the hypothesis that accounted for the most evidence was pitted against children’s prior beliefs. Children who considered alternative outcomes privileged the hypothesis that accounted for more observations, whereas those who explained relied on prior beliefs. Findings demonstrate that counterfactuals recruit attention to disambiguating evidence and outperform explanation when data contrast with existing beliefs.     

Toddlers learn and flexibly apply multiple possibilities

The ability to consider multiple possibilities forms the basis for a wide variety of human-unique cognitive capacities. When does this skill develop? Previous studies have narrowly focused on children's ability to prepare for incompatible future outcomes. Here, we investigate this capacity in a causal learning context. Adults (N = 109) and 18- to 30-month olds (N = 104) observed evidence that was consistent with two hypotheses, each occupying a different level of abstraction (individual vs. relational causation). Results suggest that adults and toddlers identified multiple candidate causes for an effect, held these possibilities in mind, and flexibly applied the appropriate hypothesis to inform subsequent inferences. These findings challenge previous suggestions that the ability to consider multiple alternatives does not emerge until much later in development.     

Children’s Developing Ability to Resolve Disagreements by Integrating Perspectives

Children live in a world where disagreement is commonplace. Although disagreement can sometimes be explained by differences in people’s reliability, disagreement may also indicate that the referent elicits multiple perspectives. The present studies (total N = 129, 5- to 12-year-old ethnically diverse U.S. children, 42% girls) examined children’s ability to resolve disagreement among two individuals by identifying referents that integrated the perspectives, and considered the extent to which any age-related change could be explained by epistemological understanding (i.e., acknowledging that two perspectives can be right). Children’s age was positively correlated with their ability to integrate perspectives, and children performed at above-chance levels by approximately 10 years of age. Age differences in integrating perspectives were partially accounted for by epistemological understanding.