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.     

Evaluating the effectiveness of interactive computer tutorials for an undergraduate mathematical literacy course

This article describes a study of learning when students used interactive spreadsheet‐based computer tutorials in a mathematical literacy course. It foregrounds theories relating to the role of computer technology (and specifically spreadsheets) as a mediator for learning of mathematics. It outlines the application of quantitative methods involving pre‐ and post‐testing of students, both in the computer laboratory and in the lecture sessions, and discusses factors constraining the experimental design and the usefulness of the results. There are indications that the data reveal real differences between the learning experiences in the lecture sessions and the computer laboratories. It appears that in some respects the computer tutorials were more effective in conveying the concepts than the lecture sessions were. A method of analysing and representing the data, that tracks the extent of learning of concepts through the pre‐ and post‐tests, was developed. It allows for the performance of sub‐groups of students to be examined separately. This analysis shows that simple definitions of disadvantage (such as having English as a second language) are inadequate to account for the poor performance of students in the lower quartile.     

The work of Ambroise Tardieu: the first definitive description of child abuse

The first important monograph describing the battered child syndrome was written in 1860 by Ambroise Tardieu, a French forensic physician. Here is a translation of his article, published in the Annales d'hygiene publique et de medecine legale, with the title "Etude medico-legale sur les sevices et mauvais traitements exerces sur des enfants." The first part of his article is entirely translated. A brief summary of the 32 cases report described by Tardieu in the second part of his article is presented.     

Time Spent Gaming and Social Competence in Children: Reciprocal Effects Across Childhood

Electronic games are popular and many children spend much time on this activity. Here we investigate whether the quantity of time children spend on gaming is related to their social development, making this the first study to examine this relationship in children. We examine prospective relations between time spent gaming and social competence in a community sample of Norwegian 6 year olds (n = 873) followed up at ages 8, 10, and 12, controlling for socioeconomic status, body mass index, and time spent gaming together with friends. Results revealed that greater social competence at both 8 and 10 years predicted less gaming 2 years later and that more age-10 gaming predicted less social competence at age 12 but only among girls.     

Quality Assurance and Evaluation through Brazilian lenses: an exploration into the validity of umbrella concepts

In our present research we address the question of whether it is valid to apply the Quality Assurance and Evaluation (QAE) umbrella concept, which was formulated to explain new phenomena in European educational governance, to similar developments in Brazilian basic education. This led us to reflect on the possible pitfalls and potential strengths of using umbrella concepts as analytical tools. This article presents this exploration and its operationalisation. We confronted in-built assumptions in QAE with the contested, consensual and creative use of the notion of quality in Brazilian basic education, and looked for relationships. Our analysis shows that the Brazilian developments reiterate the relationships concerning global interconnectivity, and challenges those pertaining to conformity. We argue that the main risks of using umbrella concepts seem to concern the re-production of understandings, which frequently leads to the disregarding of deviation.