5,219 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 ‘wreckage’ 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 ‘aid-funded’, who turned up for a short period of time to tell the locals what they should be doing! The naiveté of some of these people was truly remarkable (or perhaps they just didn’t care?). Failure of the program or reforms was generally attributed to the locals not ‘seeing it through’ 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.)
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User interface development and software environments : the Chiron-1 system
User interface development systems for software environments have to cope with the broad, extensible and dynamic character of such environments, must support internal and external integration, and should enable various software development strategies. The Chiron-1 system adapts and extends key ideas from current research in user interface development systems to address the particular demands of software environments. Important Chiron-1 concepts are: separation of concerns, dynamism, and open architecture. We discuss the requirements on such user interface development systems, present the Chiron-1 architecture and a scenario of its usage, detail the concepts it embodies, and report on its design and prototype implementation
Application of digital particle image velocimetry to insect aerodynamics: measurement of the leading-edge vortex and near wake of a Hawkmoth.
Some insects use leading-edge vortices to generate high lift forces, as has been inferred from qualitative smoke visualisations of the flow around their wings. Here we present the first Digital Particle Image Velocimetry (DPIV) data and quantitative analysis of an insect’s leading-edge vortex and near wake at two flight speeds. This allows us to describe objectively 2D slices through the flow field of a tethered Tobacco Hawkmoth (Manduca sexta). The near-field vortex wake appears to braodly resemble elliptical vortex loops. The presence of a leading-edge vortex towards the end of the downstroke is found to coincide with peak upward force production measured by a six-component force–moment balance. The topology of Manduca’s leading-edge vortex differs from that previously described because late in the downstroke, the structure extends continuously from wingtip across the thorax to the other wingtip
ECONOMIC IMPACTS OF FUSARIUM HEAD BLIGHT IN WHEAT
Fusarium Head Blight (FHB), commonly known as scab, has been a severe problem for wheat producers in recent years. This study estimates the economic value of crop losses suffered by wheat producers in the 1990s. Nine states and three wheat classes are included in the analysis, which considers the effects of scab on both production and average prices received. The cumulative value of losses (1991-97) in scab-affected regions is estimated at $1.3 billion. Two states, North Dakota and Minnesota, account for over two-thirds of these dollar losses.Fusarium Head Blight, scab, crop losses, wheat, Production Economics,
SHORTFALLS IN 1997 NET FARM INCOME IN NORTH DAKOTA (Prepared for Senators Byron Dorgan and Kent Conrad)
North Dakota net farm income declined in 1997 due to adverse weather conditions and low prices. The total income loss in 1997 was estimated to be 290 million due to weather and diseases, and $104 million due to lower-than-average prices. Net farm income losses were largest in Region 3 (Northeast), followed by Regions 1 (Northwest) and 6 (East Central). HRS wheat accounted for the largest income loss, followed by durum and barley.Net farm income, crop losses, weather conditions, North Dakota input output model, Agricultural Finance,
Long term changes in health-related quality of life for people with heart failure:the ECHOES study
Aims: Heart failure (HF) impairs all aspects of health-related quality of life (HRQoL), but little is known about the effect of developing HF on HRQoL over time. We aimed to report changes in HRQoL over a 13-year period. Methods and results: HRQoL was measured in the Echocardiographic Heart of England Screening (ECHOES) study and the ECHOES-X follow-up study (N = 1618) using the SF-36 questionnaire (Version 1). Mixed modelling compared changes in HRQoL across diagnostic groups, adjusting for potential predictors and design variables. Patients who had developed HF with reduced ejection fraction (HFrEF) or HF with preserved ejection fraction (HFpEF) at rescreening had significantly greater reduction in physical functioning (PF) and role physical (RP) scores compared with those without HF; adjusted mean difference in PF: HFrEF −16.1, [95% confidence interval (CI) −22.2 to −10.1]; HFpEF −14.6, (95% CI −21.2 to −8.1); in RP: HFrEF −20.7, (95% CI −31.8 to −9.7); HFpEF −19.3, (95% CI −31.0 to −7.6). Changes in HRQoL of those with a HF diagnosis at baseline and rescreen, with exception of role emotion, were similar to those without HF but started from a much lower baseline score. Conclusions: People with a new diagnosis of HF at rescreening had a significant reduction in HRQoL. Conversely, for those with HF detected on initial screening, little change was observed in HRQoL scores on rescreening. Further research is required to understand the development of HF over time and to test interventions designed to prevent decline in HRQoL, potentially through earlier diagnosis and treatment optimization.</p
Magnetorotational Instability in Liquid Metal Couette Flow
Despite the importance of the magnetorotational instability (MRI) as a
fundamental mechanism for angular momentum transport in magnetized accretion
disks, it has yet to be demonstrated in the laboratory. A liquid sodium
alpha-omega dynamo experiment at the New Mexico Institute of Mining and
Technology provides an ideal environment to study the MRI in a rotating metal
annulus (Couette flow). A local stability analysis is performed as a function
of shear, magnetic field strength, magnetic Reynolds number, and turbulent
Prandtl number. The later takes into account the minimum turbulence induced by
the formation of an Ekman layer against the rigidly rotating end walls of a
cylindrical vessel. Stability conditions are presented and unstable conditions
for the sodium experiment are compared with another proposed MRI experiment
with liquid gallium. Due to the relatively large magnetic Reynolds number
achievable in the sodium experiment, it should be possible to observe the
excitation of the MRI for a wide range of wavenumbers and further to observe
the transition to the turbulent state.Comment: 12 pages, 22 figures, 1 table. To appear in the Astrophysical Journa
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