Robust estimation using the Huber function with a data-dependent tuning constant

Robust estimation often relies on a dispersion function that is more slowly varying at large values than the square function. However, the choice of tuning constant in dispersion functions may impact the estimation efficiency to a great extent. For a given family of dispersion functions such as the Huber family, we suggest obtaining the "best" tuning constant from the data so that the asymptotic efficiency is maximized. This data-driven approach can automatically adjust the value of the tuning constant to provide the necessary resistance against outliers. Simulation studies show that substantial efficiency can be gained by this data-dependent approach compared with the traditional approach in which the tuning constant is fixed. We briefly illustrate the proposed method using two datasets.

Synthesis of profluorescent isoindoline nitroxides via palladium-catalysed Heck alkenylation

The synthesis of a new structural class of isoindoline nitroxides (aminoxyls), accessible via the palladium-catalysed Heck reaction, is presented. Reaction of the aryl bromoamine, 5-bromo-1,1,3,3-tetramethylisoindoline (4) or dibromoamine, 5,6-dibromo-1,1,3,3-tetramethylisoindoline (5) or the analogous bromonitroxides 6 and 7 with methyl acrylate gives the acrylate substituted tetramethylisoindoline amines 8 and 10 and nitroxides 12 and 14. Similarly, the reaction of the aryl bromides and dibromides 4–7 with methyl 4-vinylbenzoate gives the carboxystyryl substituted tetramethylisoindoline amines 9 and 11 and the analogous nitroxides 13 and 15. The carboxystyryl tetramethylisoindoline nitroxides demonstrate strongly suppressed fluorescence, which is revealed upon removal of the free radical by reduction or radical coupling.

Citizen journalism and everyday life : A case study of Germany’s myHeimat.de

Much recent research into citizen journalism has focussed on its role in political debate and deliberation. Such research examines important questions about citizen participation in democratic processes – however, it perhaps places undue focus on only one area of journalistic coverage, and presents a challenge which only a small number of citizen journalism projects can realistically hope to meet. A greater opportunity for broad-based citizen involvement in journalistic activities may lie outside of politics, in the coverage of everyday community life. A leading exponent of this approach is the German-based citizen journalism Website myHeimat.de, which provides a nationwide platform for participants to contribute reports about events in their community. myHeimat takes a hyperlocal approach but also allows for content aggregation on specific topics across multiple local communities; Hannover-based newspaper publishing house Madsack has recently acquired a stake in the project. Drawing on extensive interviews with myHeimat CEO Martin Huber and Madsack newspaper editors Peter Taubald and Clemens Wlokas during October 2008, this paper analyses the myHeimat project and examines its applicability beyond rural and regional areas in Germany; it investigates the question of what role citizen journalism may play beyond the political realm.

Protecting the most vulnerable in consumer credit transactions

There are two key ways in which the Australian Uniform Consumer Credit Code seeks to protect consumers in relation to consumer credit transactions. The first is by means of disclosure regulation where information is required to be disclosed to the consumer before the credit contract is entered into and the second is by way of “safety net” provisions, where contracts can be varied or set aside in the event of hardship, a finding that the transaction was unjust, or a finding of unconscionable fees or charges. This article explores the limitations of both of these means of protection, particularly in the case of vulnerable, low-income consumers. In order to highlight the inadequacies of these forms of consumer protection and the need for regulatory reform, we draw on interviews conducted with 30 low-income consumers who had recently signed a credit contract, focusing on their understanding of information disclosed in the contract, as well as their responses to hypothetical unfair terms and their understanding of their rights, for example in the event of an unjust transaction. These interviews were conducted as part of a joint research project between Brotherhood of St Laurence and Griffith University’s Centre for Credit and Consumer Law, funded by Consumer Affairs Victoria.

Contemporary consumer law : the role and effectiveness of regulation in consumer protection

This issue of the Griffith Law Review focuses on consumer law, and the pervasive nature of this area of law. We are all consumers, but do not necessarily identify as such, nor are we a homogeneous group. The boundaries of

The role of land use and psycho-social factors in high density residents' work travel mode choices : implications for sustainable transport policy

Imperatives to improve the sustainability of cities often hinge upon plans to increase urban residential density to facilitate greater reliance on sustainable forms of transport and minimise car use. However there is ongoing debate about whether high residential density land use in isolation results in sustainable transport outcomes. Findings from surveys with residents of inner-urban high density dwellings in Brisbane, Australia, suggest that solo car travel accounts for the greatest modal share of typical work journeys and attitudes toward dwelling and neighbourhood transport-related features, residential sorting factors and socio-demographics, alongside land use such as public transport availability, are significantly associated with work travel mode choice. We discuss the implications of our findings for transport policy and management including encouraging relatively sustainable intermodal forms of transport for work journeys.

New routes for the field trip

As with the broader field of education research, most writing on the subject of school excursions and field trips has centred around progressive/humanist concerns for building pupil’s self-esteem and for the development of the ‘whole child’. Such research has also stressed the importance of a broad, grounded, and experiential curriculum - as exemplified by subjects containing these extra-school activities - as well as the possibility of strengthening the relationship between student and teacher. Arguing that this approach to the field trip is both exhausted of ideas and conceptually flawed, this paper proposes some alternate routes into the area for the prospective researcher. First, it is argued that by historicising the subject matter, it can be seen that school excursions are not simply the product of the contemporary humanist desire for diverse and fulfilling educational experiences, rather they can, in part, be traced to eighteenth century beliefs among the English gentry that travel formed a crucial component of a good education, to the advent of an affordable public rail system, and to school tours associated with the Temperance movement. Second, field trips can be understood from within the associated framework of concerns over the governance of tourism and the organisation of disciplinary apparatuses for the production of an educated and regulated citizenry. Far from being a simple learning experience, museums and art galleries form part of a complex of disciplinary and power relations designed to produce a populace with very specific capacities, aspirations and styles of public conduct. Finally, rather than allowing children ‘freedom’ from the constraints of the classroom, on the contrary, through the medium of the field-trip, children can become accustomed to having their activities governed in the broader domain of the generalised community . School excursions thereby constitute an effective tactic through which young people have their conduct managed, and their social and scholastic identities shaped and administered.

The impact of child sexual abuse on victims/survivors: Exploring posttraumatic outcomes as a function of childhood sexual abuse

There is sparse systematic examination of the potential for growth as well as distress that may occur for some adult survivors of childhood sexual abuse. The presented study explored posttraumatic growth and its relationship with negative posttrauma outcomes within the specific population of survivors of childhood sexual abuse (N = 40). Results showed that 95% of the participants experienced clinically significant post-traumatic stress disorder symptomatology related to their childhood sexual abuse. In conjunction with these high levels of negative symptoms, the population evidenced posttraumatic growth levels that were comparable to other trauma samples. This research has clinical relevance in terms of adding to the knowledge base on sexual abuse and the usefulness of this knowledge in therapeutic interventions and relationships.

Glycaemic index and glycaemic load intake patterns in older Australian women

Aims: Dietary glycemic index (GI) and glycemic load (GL) have been associated with risk of chronic diseases, yet limited research exists on patterns of consumption in Australia. Our aims were to investigate glycemic carbohydrate in a population of older women, identify major contributing food sources, and determine low, moderate and high ranges. Methods: Subjects were 459 Brisbane women aged 42-81 years participating in the Longitudinal Assessment of Ageing in Women. Diet history interviews were used to assess usual diet and results were analysed into energy and macronutrients using the FoodWorks dietary analysis program combined with a customised GI database. Results: Mean±SD dietary GI was 55.6±4.4% and mean dietary GL was 115±25. A low GI in this population was ≤52.0, corresponding to the lowest quintile of dietary GI, and a low GL was ≤95. GI showed a quadratic relationship with age (P=0.01), with a slight decrease observed in women aged in their 60’s relative to younger or older women. GL decreased linearly with age (P<0.001). Bread was the main contributor to carbohydrate and dietary GL (17.1% and 20.8%, respectively), followed by fruit (15.5% and 14.2%), and dairy for carbohydrate (9.0%) or breakfast cereals for GL (8.9%). Conclusions: In this population, dietary GL decreased with increasing age, however this was likely to be a result of higher energy intakes in younger women. Focus on careful selection of lower GI items within bread and breakfast cereal food groups would be an effective strategy for decreasing dietary GL in this population of older women.

Glycaemic load is associated with insulin resistance in older Australian women

Background: Diets with a high postprandial glycemic response may contribute to long-term development of insulin resistance and diabetes, however previous epidemiological studies are conflicting on whether glycemic index (GI) or glycemic load (GL) are dietary factors associated with the progression. Our objectives were to estimate GI and GL in a group of older women, and evaluate cross-sectional associations with insulin resistance. Subjects and Methods: Subjects were 329 Australian women aged 42-81 years participating in year three of the Longitudinal Assessment of Ageing in Women (LAW). Dietary intakes were assessed by diet history interviews and analysed using a customised GI database. Insulin resistance was defined as a homeostasis model assessment (HOMA) value of >3.99, based on fasting blood glucose and insulin concentrations. Results: GL was significantly higher in the 26 subjects who were classified as insulin resistant compared to subjects who were not (134±33 versus 114±24, P<0.001). In a logistic regression model, an increment of 15 GL units increased the odds of insulin resistance by 2.09 (95%CI 1.55, 2.80, P<0.001) independently of potential confounding variables. No significant associations were found when insulin resistance was assessed as a continuous variable. Conclusions: Results of this cross-sectional study support the concept that diets with a higher GL are associated with increased risk of insulin resistance. Further studies are required to investigate whether reducing glycemic intake, by either consuming lower GI foods and/or smaller serves of carbohydrate, can contribute to a reduction in development of insulin resistance and long-term risk of type 2 diabetes.

Teaching and learning in a context-based chemistry classroom

Many current chemistry programs privilege de-contextualised conceptual learning, often limited by a narrow selection of pedagogies that too often ignore the realities of studentse own lives and interests (e.g., Tytler, 2007). One new approach that offers hope for improving studentse engagement in learning chemistry and perceived relevance of chemistry is the context-based approach. This study investigated how teaching and learning occurred in one year 11 context-based chemistry classroom. Through an interpretive methodology using a case study design, the teaching and learning that occurred during one term (ten weeks) of a unit on Water Quality are described. The researcher was a participant observer in the study who co-designed the unit of work with the teacher. The research questions explored the structure and implementation of the context-based approach, the circumstances by which students connected concepts and context in the context-based classroom and the outcome of the approach for the students and the teacher. A dialectical sociocultural theoretical framework using the dialectics of structure | agency and agency | passivity was used as a lens to explore the interactions between learners in different fields, such as the field of the classroom and the field of the local community. The findings of this study highlight the difficulties teachers face when implementing a new pedagogical approach. Time constraints and opportunities for students to demonstrate a level of conceptual understanding that satisfied the teacher, hindered a full implementation of the approach. The study found that for high (above average) and sound (average) achieving students, connections between sanctioned science content of school curriculum and the studentse out-of-school worlds were realised when students actively engaged in fields that contextualised inquiry and gave them purpose for learning. Fluid transitions or the toing and froing between concepts and contexts occurred when structures in the classroom afforded students the agency to connect concepts and contexts. The implications for teaching by a context-based approach suggest that keeping the context central, by teaching content on a "need-to-know" basis, contextualises the chemistry for students. Also, if teachers provide opportunities for student-student interactions and written work student learning can improve.

Comparison of multiple and novel measures of dietary glycemic carbohydrate with insulin resistant status in older women

BACKGROUND:Previous epidemiological investigations of associations between dietary glycemic intake and insulin resistance have used average daily measures of glycemic index (GI) and glycemic load (GL). We explored multiple and novel measures of dietary glycemic intake to determine which was most predictive of an association with insulin resistance.METHODS:Usual dietary intakes were assessed by diet history interview in women aged 42-81 years participating in the Longitudinal Assessment of Ageing in Women. Daily measures of dietary glycemic intake (n = 329) were carbohydrate, GI, GL, and GL per megacalorie (GL/Mcal), while meal based measures (n = 200) were breakfast, lunch and dinner GL; and a new measure, GL peak score, to represent meal peaks. Insulin resistant status was defined as a homeostasis model assessment (HOMA) value of >3.99; HOMA as a continuous variable was also investigated.RESULTS:GL, GL/Mcal, carbohydrate (all P < 0.01), GL peak score (P = 0.04) and lunch GL (P = 0.04) were positively and independently associated with insulin resistant status. Daily measures were more predictive than meal-based measures, with minimal difference between GL/Mcal, GL and carbohydrate. No significant associations were observed with HOMA as a continuous variable.CONCLUSION:A dietary pattern with high peaks of GL above the individual's average intake was a significant independent predictor of insulin resistance in this population, however the contribution was less than daily GL and carbohydrate variables. Accounting for energy intake slightly increased the predictive ability of GL, which is potentially important when examining disease risk in more diverse populations with wider variations in energy requirements.