A cause of water-sensitivity in modern oil paint films: The formation of magnesium sulphate

Unvarnished twentieth-century oil paintings are often sensitive to aqueous swabbing, a method routinely employed by conservators for surface cleaning. This study proposes a connection between sensitivity and the presence of magnesium sulphate heptahydrate which has been identified on the surface of some of water-sensitive paintings. The probable source of magnesium is magnesium carbonate, an additive in some twentieth-century oil paints, which has reacted with atmospheric sulphur dioxide (SO₂). Films made using modern manufactured paints and formulations made in the laboratory were exposed to gaseous SO₂ and raised relative humidity and examined using scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction to characterize the crystalline entities. Films containing magnesium carbonate formed magnesium sulphite and sulphate hydrates. Films containing zinc oxide were also investigated. These formed zinc and sulphur containing salts. Sensitivity to swabbing with water before and after exposure was evaluated. Films that developed salts, demonstrated increased sensitivity to aqueous swabbing after exposure to SO₂. Findings suggest that increased water sensitivity may be due to a combination of the formation of hygroscopic degradation products and to weakening of the paint film due to salt-induced disruption of the surface.     

Race,Choice and Richmond Public Schools: New Possibilities and Ongoing Challenges for Diversity in Urban Districts

Several contemporary demographic trends suggest that school systems in America’s central cities, typically characterized by high levels of racial and economic isolation, are being presented with new opportunities to create quality, diverse schools. Still, numerous obstacles linger. Using multiple sources of data and innovative mapping tools, this case study explores an urban district experiencing population growth and change and several different manifestations of school choice. Analyses indicate that levels of black-white elementary school segregation have risen rapidly over the past two decades, and now surpass residential segregation levels. The increase in school segregation has occurred alongside a district policy emphasis on both choice and neighborhood schools. While the current elementary school zones present a number of opportunities for further racial and economic diversity, high shares of students transferring out of their zone—either to another setting in the district or to a private school—undermine those possibilities. The example of Richmond, Virginia has important policy implications for countless other urban districts grappling with demographic shifts and the growth and popularity of school choice. Both trends offer crucial possibilities for central city school systems, but without careful attention to policy, will likely result in further stratification.     

Use of Lecture Capture in Higher Education - Lessons from the Trenches

Lecture capture, defined here as the capturing of some or all elements of a live lecture in digital format, is becoming increasingly popular in higher education. Despite this increase in popularity, fewer than 10% of institutes of higher education globally have adopted comprehensive lecture capture systems. So, the majority of instructors wanting to use lecture capture technology will find themselves having to acquire their own technology and do the capture themselves. There are several factors that influence the use of lecture capture, including the instructor’s level of comfort with technology, their budget, and the context in which they will be using the tool. Using case studies of our own experiences, we hope to illustrate a variety of ways in which lecture capture can be appropriately used in higher education in this way. Following this, we outline several challenges that we faced and provide recommendations for how to overcome these. Lastly, we describe some issues that should be considered and addressed before getting started using lecture capture technology in a way that is customized to suit the needs of both professor and student. We hope that by following the guidelines outlined in this paper, and by seeing practical examples of how lecture capture can be used in a variety of contexts, the transition from idea to implementation will be an easier one.     

Poor Auditory Task Scores in Children With Specific Reading and Language Difficulties: Some Poor Scores Are More Equal Than Others

Children with specific reading disability (SRD) or specific language impairment (SLI), who scored poorly on an auditory discrimination task, did up to 140 runs on the failed task. Forty-one percent of the children produced widely fluctuating scores that did not improve across runs (untrainable errant performance), 23% produced widely fluctuating scores in early runs that did improve across runs (trainable errant performance), 26% produced stable poor scores that did not improve across runs (untrainable nonerrant poor performance), and 23% produced stable poor scores that did improve across runs (trainable nonerrant performance). In most cases, trainable and untrainable errant performance, and nonerrant poor performance, could be predicted from a child's first two auditory task scores. These results illustrate that poor auditory task scores produced by children with SRD and SLI do not reflect a unitary deficit, do not necessarily reflect poor perception, and do not always respond to training.     

Referees' use of heuristics: The moderating impact of standard of competition

Abstract

The influence of players' standard of competition on referees' decision making was investigated. Standard of competition was examined by studying 30 handball matches, 15 at League and 15 at National standard. At both standards, we examined two types of refereeing decision (sporting and disciplinary) after transgressions that varied in ambiguity. The results indicated that referees made more lenient decisions at higher standards of competition, but this tendency depended on the type of decision being made and ambiguity in the offence. The hypothesis that referees use standard of competition as a judgemental heuristic, but in varying ways, was supported.     

Delivering Australian vocational qualifications through action learning

In 2009, Skills Tasmania approached the authors to deliver their Lean Action Learning programme in Tasmania. This programme had run successfully in South Australia for some five years. For Tasmania, a requirement was that participants in the programme be eligible for a nationally recognised VET qualification on completion of the programme. This had not been a requirement in South Australia. This Account of Practice outlines how the authors were able to meet requirements without compromising the action learning approach. Qualifications are awarded based on observed performance, mentoring and evidence gathered. The authors describe the processes used for project planning, qualification mapping, mentoring, evidence gathering and assessment.     

Analysis of named entity recognition and linking for tweets

Applying natural language processing for mining and intelligent information access to tweets (a form of microblog) is a challenging, emerging research area. Unlike carefully authored news text and other longer content, tweets pose a number of new challenges, due to their short, noisy, context-dependent, and dynamic nature. Information extraction from tweets is typically performed in a pipeline, comprising consecutive stages of language identification, tokenisation, part-of-speech tagging, named entity recognition and entity disambiguation (e.g. with respect to DBpedia). In this work, we describe a new Twitter entity disambiguation dataset, and conduct an empirical analysis of named entity recognition and disambiguation, investigating how robust a number of state-of-the-art systems are on such noisy texts, what the main sources of error are, and which problems should be further investigated to improve the state of the art.