4,551 research outputs found
The influence of context on science curricula: Observations, conclusions and some recommendations for curriculum development and implementation
The genesis of this project and book was our experiences of teaching science and science education at various levels in developing countries; in the Pacific and the Caribbean. These experiences along with numerous conversations with other teachers and educators who had worked in Africa and elsewhere left us with something of a sense of despair. We constantly confronted Western or foreign science curricula which were plainly alien to science learners in non-Western contexts. We witnessed numerous curricula reforms and professional development initiatives, many of which seemed doomed to failure. In fact Helu-Thaman (1991) referred to the âwreckageâ of aid-funded curricula initiatives all around the Pacific. Probably the most alarming aspect in all of this was the role of the foreign expert. Someone, normally âaid-fundedâ, who turned up for a short period of time to tell the locals what they should be doing! The naivetĂ© of some of these people was truly remarkable (or perhaps they just didnât care?). Failure of the program or reforms was generally attributed to the locals not âseeing it throughâ or not quite understanding the new curriculum initiatives. There was little effort made to take into account local conditions or the views of local experts, especially teachers
Science education in context: An overview and some observations
This book presents an international perspective of the influence of educational context on science education. By this we mean the context in which the teaching and learning takes place, rather than the use of a context-based approach to learning and teaching (Pilot & Bulte, 2006). The focus is on the interactions between curriculum development and implementation in non-Western and non- English-speaking contexts (i.e., outside the UK, USA, Australia, NZ, etc.)
Constraining alternative theories of gravity using pulsar timing arrays
The opening of the gravitational wave window by ground-based laser
interferometers has made possible many new tests of gravity, including the
first constraints on polarization. It is hoped that within the next decade
pulsar timing will extend the window by making the first detections in the
nano-Hertz frequency regime. Pulsar timing offers several advantages over
ground-based interferometers for constraining the polarization of gravitational
waves due to the many projections of the polarization pattern provided by the
different lines of sight to the pulsars, and the enhanced response to
longitudinal polarizations. Here we show that existing results from pulsar
timing arrays can be used to place stringent limits on the energy density of
longitudinal stochastic gravitational waves. Paradoxically however, we find
that longitudinal modes will be very difficult to detect due to the large
variance in the pulsar-pulsar correlation patterns for these modes. Existing
upper limits on the power spectrum of pulsar timing residuals imply that the
amplitude of vector longitudinal and scalar longitudinal modes at frequencies
of 1/year are constrained: and , while the bounds on the energy density for a
scale invariant cosmological background are: and .Comment: 5 pages, 4 figure
Recommended from our members
Tropical rainforests getting their fix: The ecological drivers and consequences of nitrogen-fixing trees in regenerating Costa Rican rainforests
Tropical rainforests have an unparalleled capacity to sequester carbon, harbor biodiversity, and cycle water and nutrients due to their high rates of primary production. The large biomass stocks and rapid regeneration rates of these forests are often attributed to ample soil nitrogen and quick recovery of the nitrogen cycle in tropical soils following disturbance. Symbiotic nitrogen-fixing trees, which are relatively abundant at tropical latitudes, have the greatest capacity to provide tropical rainforests with new nitrogen, yet the ecological drivers of tropical symbiotic nitrogen fixers and their effects on the forests they inhabit are not well understood. This dissertation consists of four chapters that examine the patterns, environmental controls, and ecological consequences of symbiotic nitrogen-fixing trees in regenerating and intact rainforests in the Caribbean lowlands of Costa Rica. In chapter 1, I use field sampling in a chronosequence of rainforest plots to show that symbiotic nitrogen fixation declines through succession despite increases in the basal area of nitrogen-fixing trees. Chapters 2 and 3 describe results from a controlled shadehouse experiment assessing the effects of light, soil nitrogen, and plant competition on nitrogen fixation rates and the growth and biomass allocation of nitrogen fixers and non-fixers. In chapter 2, I demonstrate that light regulates nitrogen fixation more strongly than soil nitrogen availability. This is a departure from the historical focus on soil nitrogen as the primary regulator of nitrogen fixation and has the potential to resolve longstanding paradoxes of tropical nitrogen cycling. In chapter 3, I show that nitrogen fixation provides some resistance to competitive effects from neighboring plants in nitrogen-limited conditions, and that nitrogen fixers in these conditions downregulate their fixation rates in the presence of a competitor. This chapter also demonstrates that nitrogen fixation does not represent a significant structural cost to the plant, as reduced root biomass of nitrogen fixers more than compensates for allocation to nodule production. Finally, in Chapter 4, I demonstrate that nitrogen-fixing trees in our chronosequence plots do not promote forest growth, as expected given their capacity to fertilize their neighbors, but rather inhibit forest growth because they are strong competitors. These chapters describe several unexpected findings â i.e. that light primarily drives nitrogen fixation and that nitrogen fixers slow forest growth â which provide new and important insight into the role that nitrogen-fixing trees play in the growth of Costa Rican rainforests
Spatial distribution of trace metals in urban soils and road dusts : an example from Manchester, UK
Urban soil quality is of concern under current UK contaminated land legislation in terms of potential
impacts on human health, due to the legacy of industrial, mining and waste disposal activities and the
fact that soils can act as a sink for potentially harmful substances (PHS) in the urban environment. As part
of the the Geochemical Baseline Survey of the Environment (G-BASE) project of the British Geological
Survey (BGS), 27 UK cities have been surveyed to establish baselines and assess the quality of urban
soils. The G-BASE soil geochemical dataset for Manchester forms the basis of this project. Another
medium that is a likely sink for PHS in urban environments is road dust sediment (RDS). RDS forms as
an accumulation of particles on pavements and road surfaces, and has been shown to be both spatially
and temporally highly variable in composition, as it is more susceptible to remobilisation and transport.
RDS has been documented as carrying a high loading of contaminant species, including significant
amounts of trace metals. Geochemical data from both soils and RDS, despite having different properties,
are essential for environmental assessment in urban areas. Although studies of PHS in RDS and soils
have been published, little is known about the spatial, geochemical and mineralogical linkages between
these two media. The aim of this research is to define and establish these linkages, and produce novel
mineralogical data on the PHSâparticulate relationships within soils and RDS
Linking Cooperative Education and Education for sustainability: A New Direction for Cooperative Education?
In this article the authors propose that co-op practitioners and researchers need to constantly re-examine the practice and future of cooperative education. Co-op currently introduces large numbers of graduates into the business and manufacturing employment sectors. A number of authors have argued that co-op graduates rapidly advance in companies and assume middle and senior management roles. These co-op graduates and their non-co-op counterparts become the business and commercial leaders of the future. Here we argue that one beneficial future direction for co-op could be in the area of graduate understanding about education for sustainability (EfS). This paper begins with a description of the principles that underpin concepts for both EfS and cooperative education and examines three propositions as to how cooperative education might act as a vehicle for
delivering aspects of EfS
Irrigation of olives in Western Australia
Olives can be grown without irrigation in the south-west of Western Australia. However, to obtain maximum yield irrigation is required. The yields obtained from unirrigated crops may be half those of irrigated crops, with the actual yield decrease being dependent on the rainfall and length of growing season.
This Bulletin outlines how to calculate the irrigation requirements of olives. Considerable debate occurs as to the water requirements of olives in Western Australia.
There have been no irrigation trials on olives in this State and the crop factors outlined come from overseas experience.https://researchlibrary.agric.wa.gov.au/bulletins/1090/thumbnail.jp
Student transition to vocational education from middle secondary school in Australia and Lebanon : an exploratory study
This paper arises from an exploratory comparative study of student
transition to vocational education (voced) from middle secondary school in
Australia and Lebanon. Following an elucidation of the educational contexts in
which this transfer may occur, data arising from surveys of first-year voced
students who made this transition are presented and discussed. Converging
themes were the link between vocational education and the acquisition of
employment-related skills, and the perceived inadequacy of mainstream
secondary schooling to meet these studentsâ needs. Issues which brought about a
divergence between the two groups highlight major differences between the two
education systems. The paper ends with a series of recommendations for the
beleaguered Lebanese voced system.peer-reviewe
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