Soil carbon saturation : concept, evidence and evaluation

Current estimates of soil C storage potential are based on models or factors that assume linearity between C input levels and C stocks at steady-state, implying that SOC stocks could increase without limit as C input levels increase. However, some soils show little or no increase in steady-state SOC stock with increasing C input levels suggesting that SOC can become saturated with respect to C input. We used long-term field experiment data to assess alternative hypotheses of soil carbon storage by three simple models: a linear model (no saturation), a one-pool whole-soil C saturation model, and a two-pool mixed model with C saturation of a single C pool, but not the whole soil. The one-pool C saturation model best fit the combined data from 14 sites, four individual sites were best-fit with the linear model, and no sites were best fit by the mixed model. These results indicate that existing agricultural field experiments generally have too small a range in C input levels to show saturation behavior, and verify the accepted linear relationship between soil C and C input used to model SOM dynamics. However, all sites combined and the site with the widest range in C input levels were best fit with the C-saturation model. Nevertheless, the same site produced distinct effective stabilization capacity curves rather than an absolute C saturation level. We conclude that the saturation of soil C does occur and therefore the greatest efficiency in soil C sequestration will be in soils further from C saturation.

But does it work? Effectiveness of scientific visualisations in high school chemistry and physics instruction.

Scientific visualisations such as computer-based animations and simulations are increasingly a feature of high school science instruction. Visualisations are adopted enthusiastically by teachers and embraced by students, and there is good evidence that they are popular and well received. There is limited evidence, however, of how effective they are in enabling students to learn key scientific concepts. This paper reports the results of a quantitative study conducted in Australian physics and chemistry classrooms. In general there was no statistically significant difference between teaching with and without visualisations, however there were intriguing differences around student sex and academic ability.

One approach to finding evidence for the effectiveness of scientific visualisations in high school physics and chemistry education

Enormous amounts of money and energy are being devoted to the development, use and organisation of computer-based scientific visualisations (e.g. animations and simulations) in science education. It seems plausible that visualisations that enable students to gain visual access to scientific phenomena that are too large, too small or occur too quickly or too slowly to be seen by the naked eye, or to scientific concepts and models, would yield enhanced conceptual learning. When the literature is searched, however, it quickly becomes apparent that there is a dearth of quantitative evidence for the effectiveness of scientific visualisations in enhancing students’ learning of science concepts. This paper outlines an Australian project that is using innovative research methodology to gather evidence on this question in physics and chemistry classrooms.

Stability and change in prosocial and antisocial behavior across the transition to school : Teacher and peer perspectives

Research Findings: The transition to school is a major developmental milestone, and behavior tendencies already evident at the point of school entry can impact upon a child's subsequent social and academic adjustment. The current study aimed to investigate stability and change in the social behavior of girls and boys across the transition from day care to 1st grade. Teacher ratings and peer nominations for prosocial and antisocial behavior were obtained for 248 children belonging to 2 cohorts: school transitioning (n = 118) and day care remaining (n = 130). Data were gathered again from all children 1 year later, following the older group's entry into school. Teacher ratings of prosocial and antisocial behavior significantly predicted teacher ratings of the same behavior at Time 2 for both cohorts. Peer reports of antisocial behavior also showed significant stability, whereas stability of peer-reported prosocial behavior varied as a function of behavior type. Practice or Policy: The results contribute to understanding of trends in early childhood social behavior that potentially influence long-term developmental trajectories. Identification of some behaviors as more stable in early childhood than others, regardless of school entry, provides useful information for both the type and timing of early interventions. © 2010 Taylor & Francis Group, LLC.

The Impact of Parental Attachment on Adolescent Perception of the School Environment and School Connectedness

The extent to which students feel accepted, valued, respected and included in the school has recently surfaced as one of the most important predictors of adolescent mental health (particularly depressive symptoms). The school environment is an established predictor of school connectedness, but we set out to examine whether parental attachment predicts both adolescents' perception of the school environment and school connectedness. A study of 171 high school students from years 8 to 12 showed that parent attachment strongly predicted both. We also confirmed that the relationship between parent attachment and school connectedness is not a direct one but that parent attachment influences individual differences in the way adolescents perceive the school environment, which in turn influences school connectedness. This finding shows how multiple systems might be interlinked in influencing wellbeing in adolescents, and confirms the importance of intervening at the double level of both the family and the school system.