6,558 research outputs found
Environmental economics and the Murray-Darling river system
No full textMuch concern about the negative environmental consequences of agricultural development in Australia, including salinisation, waterlogging and algal blooms, has focused on the problems of the Murray–Darling Basin. The aim of this article is to provide an overview of the environmental problems of the Murray–Darling Basin from an economic perspective, and a selective survey of the relevant economic literature, including theoretical analysis, modelling and contributions to the development of water policy. In attempting to understand the complex problems of the Murray–Darling Basin, an eclectic approach drawing on externality, sustainability and property rights perspectives seems most appropriate.Environmental Economics and Policy, Resource /Energy Economics and Policy,
Loch Striven and its Secret Weapons
No full textDuring the Second World War, Loch Striven in western Scotland was used for testing several of Britain’s secret weapons, the most notable of them being the X-craft midget submarines and the Highball ‘bouncing bomb’, the latter being the smaller version of the Upkeep mine used against the Ruhr dams in the famous Dambuster raid of May 1943. Whereas several specimens of the Upkeep have been recovered since the war, over the years only one complete Highball was recovered. However, although the latter was earmarked to go to a museum, this did not happen and therefore there was no complete Highball on permanent display anywhere. Also, no Highball had ever been raised from Loch Striven, the site of its main trials ... that is not until our author Iain Murray initiated an undertaking to do so. In July 2017, after much planning and preparation, two Highballs were successfully lifted off the bottom of the loch
Murray-et-al-2021
No full textThis repository contains original code from author Jack C Henry for the figures of the Murray et al., 2021 manuscript published in Cell Reports
Eva Murray, author of Well Out to Sea , has been a resident of Matinicus Island
No full textEva Murray, author of Well Out to Sea , has been a resident of Matinicus Island since she moved there to teach at the island\u27s one-room schoolhouse in 1987. She discusses the differences between writing from an island and writing about an island as well as her efforts to dispel some stereotypes and myths about Matinicus through her writing
Margaret Murray (1863–1963): Pioneer Egyptologist, Feminist and First Female Archaeology Lecturer
No full textMargaret Murray, who was born 150 years ago, was one of the first archaeologists to be employed at UCL and one of the most distinguished, although her role in the history of archaeology is often underestimated. This article provides a brief outline of the career and contribution of a highly productive and innovative, if sometimes controversial, scholar, who also participated in the wider social movements of her time, particularly the campaign for women’s suffrage
Complex Adaptive System Modelling of River Murray Salinity Policy Options
No full textThis paper reports on complex adaptive system (CAS) simulation of the River Murray Basin in Australia to compare capacity of institutional options to maintain functioning of key river system within a "bandwidth" that limits irreversible system state changes and highly adverse consequences. The modelling framework characterise diverse irrigation agents who profit from water diversion and cause external salinity impacts, water and salt process that form the link between irrigator actions and agricultural profits and external costs, and a river manager who sets institutional rules. Emphasis is on the CAS nature of the system and on institutional rules to accommodate choosing actions differently based on con dition of the system has been referred to as state contingent management (Wills, 2003) or threshold based management (Roe and Van Eeten, 2001). Key findings are that policy focus on the source of salinity by reducing drainage are much more cost effective than strategies to mitigate salinity once it occurs and that state contingent dilution provision when it has high benefit and low opportunity cost is also a cost effective way to manage salinity.Resource /Energy Economics and Policy,
Bayesian inference for challenging scientific models
No full textAdvances in technology and computation have led to ever more complicated
scientific models of phenomena across a wide variety of fields. Many of these
models present challenges for Bayesian inference, as a result of computationally
intensive likelihoods, high-dimensional parameter spaces or large dataset sizes.
In this thesis we show how we can apply developments in probabilistic machine
learning and statistics to do inference with examples of these types of models.
As a demonstration of an applied inference problem involving a non-trivial
likelihood computation, we show how a combination of optimisation and
MCMC methods along with careful consideration of priors can be used to infer
the parameters of an ODE model of the cardiac action potential.
We then consider the problem of pileup, a phenomenon that occurs in
astronomy when using CCD detectors to observe bright sources. It complicates
the fitting of even simple spectral models by introducing an observation model
with a large number of continuous and discrete latent variables that scales with
the size of the dataset. We develop an MCMC-based method that can work in
the presence of pileup by explicitly marginalising out discrete variables and
using adaptive HMC on the remaining continuous variables. We show with
synthetic experiments that it allows us to fit spectral models in the presence
of pileup without biasing the results. We also compare it to neural Simulation-
Based Inference approaches, and find that they perform comparably to the
MCMC-based approach whilst being able to scale to larger datasets.
As an example of a problem where we wish to do inference with extremely
large datasets, we consider the Extreme Deconvolution method. The method
fits a probability density to a dataset where each observation has Gaussian
noise added with a known sample-specific covariance, originally intended
for use with astronomical datasets. The existing fitting method is batch EM,
which would not normally be applied to large datasets such as the Gaia catalog
containing noisy observations of a billion stars. In this thesis we propose two
minibatch variants of extreme deconvolution, based on an online variation of
the EM algorithm, and direct gradient-based optimisation of the log-likelihood,
both of which can run on GPUs. We demonstrate that these methods provide
faster fitting, whilst being able to scale to much larger models for use with
larger datasets.
We then extend the extreme deconvolution approach to work with non-
Gaussian noise, and to use more flexible density estimators such as normalizing
flows. Since both adjustments lead to an intractable likelihood, we resort to
amortized variational inference in order to fit them. We show that for some
datasets that flows can outperform Gaussian mixtures for extreme deconvolution,
and that fitting with non-Gaussian noise is now possible
Richard M. Murray [People in Control]
No full textThis issue of IEEE Control Systems Magazine speaks with Richard Murray, the recipient of the 2017 IEEE Control Systems Award; Yongxin Chen, the lead author of the paper that received the 2017 George S. Axelby Outstanding Paper Award; and Joseph Bentsman, the chair of the IEEE Control Systems Society (CSS) Technical Committee on Power Generation
Hampstead Revisited
No full textHampstead Revisited is a sampler of zines and self-published works produced by Glasgow-based artists, Iain Hetherington (in collaboration with Alex Pollard), Laurence Figgis and Stuart Murray. In relation to the Journal of Writing in Creative Practice, Hampstead Revisited is a subplot, a Trojan, a hack or an infantilist 'raid'
Sabina Murray, 30th Annual ODU Literary Festival
No full textSabina Murray is the award-winning author of the novels Slow Burn, and A Carnivore’s Inquiry, and the story collection The Caprices. A former Michener Fellow at the University of Texas and Bunting Fellow at the Radcliffe Institute of Harvard University, she received the PEN/Faulkner Award for Fiction in 2003. Murray’s stories have appeared in Ploughshares, Ontario Review, the New England Review, and other literary journals. Currently, she teaches in the MFA program at the University of Massachusetts, Amherst
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