747 research outputs found
Mobilizing learning: mobile Web 2.0 scenarios in tertiary education
Based upon three years of mobile learning (mlearning) projects, a major implementation project has
been developed for integrating the use of mobile web 2.0 tools across a variety of departments and
courses in a tertiary education environment. A participatory action research methodology guides and
informs the project. The project is based upon an explicit social constuctivist pedagogy, focusing on
student collaboration, and the sharing and critique of student-generated content using freely available
web 2.0 services. These include blogs, social networks, location aware (geotagged) image and video
sharing, instant messaging, microblogging etc… Students and lecturers are provided with either an
appropriate smartphone and/or a 3G capable netbook to use as their own for the duration of the
project. Keys to the projects success are the level of pedagogical and technical support, and the level
of integration of the tools into the courses – including assessment and lecturer modelling of the use of
the tools. The projects are supported by an intentional community of practice model, with the
researcher taking on the role of the “technology steward”. The paper outlines three different scenarios
illustrating how this course integration is being achieved, establishing a transferable model of mobile
web 2.0 integration and implementation. The goal is to facilitate a student-centred, collaborative,
flexible, context-bridging learning environment that empowers students as content producers and
learning context generators, guided by lecturers who effectively model th
Non-linear effects and aggregation bias in Ricardian models of climate change
Ricardian models predicting the impact of climate change on agriculture are typically estimated on data aggregated across counties and assuming additively separable effects of temperature and precipitation. We investigate the potential bias induced by such assumptions by using a large panel of farm-level data and estimating a semi-parametric specification. Consistent with the agronomic literature, we observe significant non-linear interaction effects, with more abundant precipitation being a mitigating factor for heat stress. This interaction disappears when the same data is aggregated in the conventional manner, leading to predictions of climate change impacts which are severely distorted
The family under the microscope: an experiment testing economic models of household choice.
We devise and execute three experiments to test key features of models of household decision-making. Using established couples (married and unmarried) we test income pooling, unanimity and Pareto efficiency. Subjects make choices individually and jointly and are asked to make predictions about their partner’s choices. Unanimity is rejected. Income pooling is not rejected in joint choice but has less explanatory power in individual choice. In direct tests both sexes do not pool income completely, but in econometric tests across all tasks, women place an equal weight on payoffs but men discount their partner’s payoffs by between 15 and 20%. We find that transparency has little impact on deviations from income pooling or indeed on behaviour generally. Many joint choices deviate from the Pareto principle in a systematic manner suggesting that choices made as a couple are more risk averse than individual decisions.experiment; household; unitary; income pooling; Pareto; family
Molecular and morphological phylogenetics of the digitate-tubered clade within subtribe Orchidinae s.s. (Orchidaceae: Orchideae)
The digitate-tubered clade (Dactylorhiza s.l. plus Gymnadenia s.l.) within subtribe Orchidinae is an important element of the North-temperate orchid flora and has become a model system for studying the genetic and epigenetic consequences of organism-wide ploidy change. Here, we integrate morphological phylogenetics with Sanger sequencing of nrITS and the plastid region trnL-F in order to explore phylogenetic relationships and phenotypic character evolution within the clade. The resulting morphological phylogenies are strongly incongruent with the molecular phylogenies, instead reconstructing through parsimony the genus-level boundaries recognised by traditional 20th Century taxonomy. They raise fresh doubts concerning whether Pseudorchis is sister to Platanthera or to Dactylorhiza plus Gymnadenia. Constraining the morphological matrix to the topology derived from ITS sequences increased tree length by 20%, adding considerably to the already exceptional level of phenotypic homoplasy. Both molecular and morphological trees agree that D. viridis and D. iberica are the earliest- diverging species within Dactylorhiza (emphasising the redundancy of the former genus Coeloglossum). Morphology and ITS both suggest that the former genus Nigritella is nested within (and thus part of) Gymnadenia, the Pyrenean endemic 'N.' gabasiana apparently forming a molecular bridge between the two radically contrasting core phenotypes. Comparatively short subtending molecular branches plus widespread (though sporadic) hybridisation indicate that Dactylorhiza and Gymnadenia approximate the minimum level of molecular divergence acceptable in sister genera. They share similar tuber morphologies and base chromosome numbers, and both genera are unusually prone to polyploid speciation. Another prominent feature of multiple speciation events within Gymnadenia is floral paedomorphosis. The 'traditional' morphological and candidate-gene approaches to phylogeny reconstruction are critically appraised.Peer reviewedFinal Published versio
Does a third bound help? Parametric and nonparametric welfare measures from a CV interval data study
Positive response density estimation from CV interval data affords efficiency gains which must be weighed against the risk of introducing potential bias during questions iteration. This study examines the effect of eliciting a third response on a set of often-used welfare measures derived in a conventional parametric setting. It then compares these with distribution-free nonparametric estimates. A third bound increases censoring probability, introduces welfare estimates sensitivity to inclusion of a theoretically relevant covariate such as wealth which also affects efficiency gains. This might well introduce complications that outweigh the expected efficiency gain. This empirical finding supports and complements previous results obtained via simulation
Using revealed preferences to estimate the value of travel time to recreation sites
The opportunity Value of Travel Time (VTT) is one of the most important parts of the total cost of recreation day-trips and arguably the most difficult to estimate. Most studies build upon the theoretical framework proposed by Becker's (1965) by using a combination of revealed and stated preference data to estimate a value of time which is uniform in all activities and under all circumstances. This restriction is relaxed by DeSerpa's (1971) model which allows the value of saving time to be activity-specific. We present the first analysis which uses actual driving choices between open access and toll roads to estimate a VTT specific for recreation trips, thereby providing a value which conforms to both Becker's and DeSerpa's models. Using these findings we conduct a Monte Carlo simulation to identify generalizable results for use in subsequent valuation studies
An experiment on risky choice amongst households
A host of experiments have examined theories of risky choice using individuals. However, many important economic decisions are taken within multi-adult households. This paper reports on the first economic experiment designed to test theories of household choice. We use established couples and face them individually and jointly with decisions involving monetary payoffs. We find that joint choices typically are more risk averse than those made by individuals. Meanwhile, choices made by couples exhibit the same kinds of departures from expected utility theory (e.g. the common ratio and common consequence effects) as are regularly recorded with individuals.http://www.grips.ac.jp/list/jp/facultyinfo/munro_alistair
ANALIZING WATER FRAMEWORK DIRECTIVE IMPACTS USING A MULTINOMIAL LOGIT LAND USE MODEL
We develop a two-stage, multinomial logit model of UK land use to investigate the impact of policy changes upon agriculture. The model utilizes a large panel database covering the entirety of England and Wales for 14 years between 1969 and 2004 integrated with the economic and physical environment determinants of all major agricultural land use types. Our model performs well in out-of-sample prediction of current land use and we use it to assess a proposed implementation of the Water Framework Directive via a tax on fertilizer. Results indicate that such policy change would generate substantial switching from arable to grassland systems, reducing significantly the amount of nitrate leaching into UK water-bodies.Water Framework Directive, Land use models, Discrete choice models, Multinomial logit, Agricultural and Food Policy, Land Economics/Use, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy,
Household versus individual valuation: what's the difference?
Standard practice in stated preference typically blurs the distinction between household and individual responses, but without a clear theoretical or empirical justification for this approach. To date there have been no empirical tests of whether values for say a two adult household elicited by interviewing one randomly selected adult are the same as the values generated by interviewing both adults simultaneously. Using cohabiting couples, we conduct a choice experiment field study valuing reductions in dietary health risks. In one treatment a random individual is chosen from the couple and interviewed alone; in the other treatment, both partners are questioned jointly. We find significant differences in household values calculated from joint as opposed to individual responses, with further variation between the values elicited from men and women. Our results question the assumption, implicit in common practice, that differences between individually and jointly elicited estimates of household values can effectively be ignored
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