32 research outputs found
Myall Lakes National Park, the Boolambayte Sand Ridge: its Extent, Vegetation, Geomorphology and Marks of European Settlement
The Boolambayte sand ridge (Bsr), recognized by Myerscough and Carolin (2014), is part of the Pleistocene sand barrier system mapped by Thom et al. (1992) and Hashimoto and Troedson (2008) in the valley of the Upper Myall River to the shores of Bombah Broadwater. Bsr comprises areas of sand on the south-western shore of Two-Mile Lake (the western arm of Boolambayte Lake). Features of Bsr reported in Myerscough and Carolin (2014) were based largely on interpretation of aerial photos; this study is based on observations on the ground. As a result, Bsr is defined more precisely. Freely draining sands were found to be in discontinuous patches along the lake shore. All patches were deposited before their eastern edges became the current lake shore, except one, which appeared to have formed as a lake sand bar. Evidence indicates that, until probably the last 2 - 3 m of the Holocene rise in sea level, waters of Two-Mile Lake joined Bombah Broadwater at the end of the lake bar running west from Bombah Point. Investigation of the vegetation of freely draining sites along Bsr shows that, though they carry Dry Sclerophyll Forest (DSF) of Myerscough and Carolin (1986 & 2014), the understoreys of most of them contain more wet heath plant spp. than do sites with DSF on sands in central parts of the Upper Myall River Valley, as described in Myerscough and Carolin (2014). Also described are various effects of European settlement to which the area has been subjected, particularly in its southern third
Decarbonisation of mobile agricultural machinery in Scotland â an evidence review
Agricultural machinery is estimated to contribute around 5-10% of Scottish Agricultureâs greenhouse gas emissions. Agricultural land in Scotland covers 5.6 million hectares and the agriculture sector represented 19% of Scotlandâs emissions in 2020. The Scottish Governmentâs Climate Change Plan update requires a 31% reduction in agricultural emissions by 2032, from 2018 levels, a pace nearly four times faster than has been achieved up to now. The decarbonisation of machinery could play a key role in Scotlandâs transition to net zero by 2045. However, there is a lack of reliable information on emissions from mobile agricultural machinery and the options, costs and pathways to decarbonisation. The use of mobile agricultural machinery varies considerably across Scotland, reflecting patterns of agricultural production. In this study we assess the suitability of selected low emission technologies to power mobile machinery
Low Temperature Opacities
Previous computations of low temperature Rosseland and Planck mean opacities
from Alexander & Ferguson (1994) are updated and expanded. The new computations
include a more complete equation of state with more grain species and updated
optical constants. Grains are now explicitly included in thermal equilibrium in
the equation of state calculation, which allows for a much wider range of grain
compositions to be accurately included than was previously the case. The
inclusion of high temperature condensates such as AlO and CaTiO
significantly affects the total opacity over a narrow range of temperatures
before the appearance of the first silicate grains.
The new opacity tables are tabulated for temperatures ranging from 30000 K to
500 K with gas densities from 10 g cm to 10 g cm.
Comparisons with previous Rosseland mean opacity calculations are discussed. At
high temperatures, the agreement with OPAL and Opacity Project is quite good.
Comparisons at lower temperatures are more divergent as a result of differences
in molecular and grain physics included in different calculations. The
computation of Planck mean opacities performed with the opacity sampling method
are shown to require a very large number of opacity sampling wavelength points;
previously published results obtained with fewer wavelength points are shown to
be significantly in error. Methods for requesting or obtaining the new tables
are provided.Comment: 39 pages with 12 figures. To be published in ApJ, April 200
Investigating the Host-Range of the Rust Fungus Puccinia psidii sensu lato across Tribes of the Family Myrtaceae Present in Australia
The exotic rust fungus Puccinia psidii sensu lato was first detected in Australia in April 2010. This study aimed to determine the host-range potential of this accession of the rust by testing its pathogenicity on plants of 122 taxa, representative of the 15 tribes of the subfamily Myrtoideae in the family Myrtaceae. Each taxon was tested in two separate trials (unless indicated otherwise) that comprised up to five replicates per taxon and six replicates of a positive control (Syzygium jambos). No visible symptoms were observed on the following four taxa in either trial: Eucalyptus grandisĂcamaldulensis, E. moluccana, Lophostemon confertus and Sannantha angusta. Only small chlorotic or necrotic flecks without any uredinia (rust fruiting bodies) were observed on inoculated leaves of seven other taxa (Acca sellowiana, Corymbia calophylla âRoseaâ, Lophostemon suaveolens, Psidium cattleyanum, P. guajava âHawaiianâ and âIndianâ, Syzygium unipunctatum). Fully-developed uredinia were observed on all replicates across both trials of 28 taxa from 8 tribes belonging to the following 17 genera: Agonis, Austromyrtus, Beaufortia, Callistemon, Calothamnus, Chamelaucium, Darwinia, Eucalyptus, Gossia, Kunzea, Leptospermum, Melaleuca, Metrosideros, Syzygium, Thryptomene, Tristania, Verticordia. In contrast, the remaining 83 taxa inoculated, including the majority of Corymbia and Eucalyptus species, developed a broad range of symptoms, often across the full spectrum, from fully-developed uredinia to no visible symptoms. These results were encouraging as they indicate that some levels of genetic resistance to the rust possibly exist in these taxa. Overall, our results indicated no apparent association between the presence or absence of disease symptoms and the phylogenetic relatedness of taxa. It is most likely that the majority of the thousands of Myrtaceae species found in Australia have the potential to become infected to some degree by the rust, although this wide host range may not be fully realized in the field
The social life of measurement:How methods have shaped the idea of culture in urban regeneration
Although âculture-led regenerationâ has been critiqued as both a concept and practice, it is clear that policy-makers continue to make efforts to use cultural activity of varying forms to achieve ends which could be (and are) described in terms of urban âregenerationâ. Whilst the idea of culture-led urban regeneration had gained considerable prominence in a range of policy by the early twenty-first century, many questions have remained over how exactly such âregenerativeâ outcomes could be convincingly demonstrated, despite much activity to attempt such demonstration over the course of preceding years. The desire for convincing evidence can be seen in a continued, and increasing, focus on evaluation, and methods aimed at providing evidence of impact and outcomes. In light of the renewed political focus in recent years on âprovingâ the effects and value of cultural activity, this paper considers the continuation of practice in this area, and asks what lessons, if any, have been learned in evaluative practice which seeks to demonstrate the regenerative effects of culture. In light of the continuation of apparently problematic practices, the paper seeks to delineate and account for what has been learned, and what has not
Estimating the phase congruency of localised frequencies
Phase congruency is a new method for detecting features in images. One of its significant strengths is its invariance to lighting variation within an image, as well as being able to detect a wide range of interesting features. We present a method for estimating the phase congruency of localised frequencies that cannot be measured separately by Gabor filters. We show that by measuring the ratio of the standard deviation to the mean energy between different phase shifted Gabor filters that we are able to estimate whether the localised frequencies are phase congruent. We then show example results from applying this estimation procedure to a set of images. We also show improvements when compared to another phase congruency detector. We conclude that the concept of estimating the phase congruency of localised features is possible, but more work is needed to mature the technique to a robust feature detector
Guiding Optical Flow Estimation
We show how optical flow estimates can be combined with boundary estimation to improve estimates of motion. The improvement is associated with blending of estimates from complementary bases of operation. The paper combines a phase-based method for optical flow with a time extended version of the phase congruency operator. By evaluation on synthetic and real image sequences, the combination of the two techniques is shown to improve motion estimation with particular advantages at motion boundaries, regions which have posed considerable difficulty for previous motion estimation techniques. The advantage is derived using the moving feature information in an extended phase congruency operator to constrain correct data in the optical flow field
Time persistent feature detection via phase congruency
The use of feature detection is a standard process within the computer vision community for simplifying a complex image to a more manageable representation. Feature detection is typically applied to individual images, even if they are a part of a more extensive image sequence. In this thesis we present new methods for feature detection via phase congruency, applied to image sequences. This work shows the improvements that can be gained from taking an image in its context. The first section of work focuses upon extending a previous feature detector, phase congruency, to operate on an image sequence. This new technique shows improvements in the robustness of the feature detector under increasing levels of noise. It also improves feature orientation description allowing for the component velocity of a feature to be evaluated. After further evaluation however this method produced undesirable results for fast moving features. In response to this, a novel method for evaluating phase congruency has been developed. The new method is achieved by modelling the filtering process used to derive phase congruency by measuring the standard deviation of the normalised energy response. Accordingly, the new method is termed statistical phase congruency. This new approach is implemented first for 2-D images, showing improvements over the initial image-based phase congruency technique. Furthermore, it is extended to detect time persistent features in image sequences whilst also providing improved results for detecting fast moving features. It is intended that the results of this work will provide a basis for detecting time persistent features under noisy conditions. The final portion of this thesis gives some conclusions and adds some direction for future work on these ideas.</p
Time persistent feature detection via phase congruency
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