Studies on thermal-oxidative degradation behaviours of raw natural rubber: PRI and thermogravimetry analysis

Thermal-oxidative degradation behaviours of raw natural rubber (NR) have been investigated by using thermogravimetry analysis in inert and oxidative atmospheres and the plasticity retention index (PRI). The activation energy E a, was calculated using Horowitz-Metzger and Coats-Redfern methods and compared with PRI. The E a values obtained by each method were in good agreement with each other. The June samples are the least stable rubbers among the studied ones, whereas February samples exhibited the highest values of activation energy, therefore in agreement with the PRI behaviour, which indicates that the thermo-oxidative stability of the June samples are the poorest during the thermo-oxidative degradation reaction. Natural rubber is a product of biological origin, and thus these variations in the values of thermal behaviour and PRI might be related to the genetic differences and alterations of climatic conditions that act directly on the synthesis of non-rubber constituents, which are generally reflected in latex and rubber properties. © 2013 Institute of Materials, Minerals and Mining.

Reporting social behaviours of mixed-species troops formed by Callithrix jacchus and Callithrix penicillata (Primate, Callitrichidae)

In New World primates, mixed-species troops have been reported. Here, we analysed the performance of affiliative and agonistic behaviours of Callithrix jacchus and Callithrix penicillata living in mixed groups. For this purpose, we recorded the interaction of the individuals from two groups located in Bauru city, in the state of Sao Paulo (Brazil). Our data show that in both groups, affiliative behaviours appeared more frequently than agonistic ones. We concluded that there is cohesion inside the mixed-species troops observed. We suggest that a deeper knowledge about the social behaviour of mixed-species troop species certainly may be useful in projects linked with the management of the impact caused by them.

Communicative repair strategies and problem behaviours of children with autism

The use of strategies by children with developmental disabilities to repair communicative breakdowns has received little attention in the research literature to date. The research that is available suggests that children with severe communication impairments may be more likely to experience communicative breakdowns than their typically developing peers. These children may also have fewer strategies available to them to repair these breakdowns. The present article reviews some of the research in this area and discusses the possible links between communicative breakdowns and the emergence of problem behaviour in children with autism. Theoretical and practical implications are considered and areas for future research are highlighted.

Gelatinisation of starch in mixtures of sugars. I. Dynamic rheological properties and behaviours of starch-honey systems

Dynamic rheological behaviour of starch-honey systems was studied using a strain-controlled rheometer. A dynamic temperature (30-130 degreesC) ramp test was used at 10 rad s(-1) frequency, 1% strain, 2 degreesC min(-1) ramp rate, 25 mm parallel plate, and 1.5 min gap, using Wheaten cornflour(TM) and five honeys to generate 25 formulations (0.34-0.80 g water/g dry starch). G', G, and eta* increased upon gelatinisation, and they reduced as the honey content was increased. For all the formulations, G' was higher than G, and tan 6 was generally less than 1.0. Key gelatinisation characterising temperatures (onset, peak and end) ranged from 96.0 to 122.3 degreesC, but did not vary much (CV < 5%) for each honey irrespective of the concentration. The influence of water, fructose and glucose, singly and in combination, on gelatinisation indices (temperature and rheological parameters) was investigated. An exponential equation was employed to describe the relationship, and relevant parameters were obtained. The consequences of the observations in the study are discussed particularly as they relate to extrusion of such systems, and possible interactions between fructose and glucose in the starch-honey systems. (C) 2003 Elsevier Ltd. All rights reserved.

The effect of music therapy services on classroom behaviours of newly arrived refugee students in Australia

This pilot study examined the effects of a short-term music therapy program on the classroom behaviours of newly arrived refugee students who were attending an intensive 'English as a Second Language' secondary school. A cross-over design with two five-week intervention periods was employed with group music therapy sessions conducted one or two times per week. Data from the Behaviour Assessment Scale for Children were used to evaluate a range of positive and negative school behaviours. A significant decrease in externalising behaviours was found with particular reference to hyperactivity and aggression. No significant differences were found in other behaviours. Explanations and implications of these findings are discussed.

Environmental and nature conservation : a facet study of concern for the quality of the natural environment

A multi-variate descriptive model of environmental and nature conservation attitudes and values is proposed and empirically supported. A mapping sentence is developed out of analysis of data from a series of Repertory Grid interviews addressing conservation employees' attitudes towards their profession's activities. The research is carried out within the meta-theoretical framework of Facet Theory. A mapping sentence is developed consisting of 9 facets. From the mapping sentence 3 questionnaires were constructed viewing the selective orientations towards environmental concern. A mapping sentence and facet model is developed for each study. Once the internal structure of this model had been established using Similarity Structure Analysis, the elements of the facets are subjected to Partial Order Scalogram Analysis with base coordinates. A questionnaire was statistically analysed to assess the relationship between facet elements and 4 measures of attitudes towards, and involvement with, conservation. This enabled the comparison of the relative strengths of attitudes associated with each facet element and each measure of conservation attitude. In general, the relationship between the social value of conservation and involvement pledges to conservation were monotonic; perceived importance of a conservation issue appearing predictive of personal involvement. Furthermore, the elements of the life area and scale facets were differentially related to attitude measures. The multi-variate descriptive model of environmental conservation values and attitudes is discussed in relation to its implications for psychological research into environmental concern and for environmental and nature conservation.