50 resultados para Macrobrachium - Classification

em Deakin Research Online - Australia


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Freshwater prawns in the genus Macrobrachium are found throughout the tropical and subtropical regions of the world, however, evolutionary relationships are poorly understood. Using molecular techniques taxonomic uncertainty is resolved and the evolution and distribution of this enigmatic genus across a range of taxonomic and geographic levels is examined.

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The systematic relationships among Australian palaemonid shrimps have been the subject of speculation for some time. A preliminary phylogenetic study was undertaken to clarify the relationships of five species, Macrobrachium intermedium (Stimpson), M. australiense (Holthuis), M. atactum (Riek), M. rosenbergii (de Man) and Palaemon serenus (Heller), using 16S rRNA mitochondrial gene sequences. Phylogenetic analyses indicated inconsistencies with the current classification in two respects. First, M. intermedium formed a very well-supported clade with P. serenus distinct from M. australiense, M. atactum and M. rosenbergii. Second, the two species from inland Australia, M. australiense and M. atactum, showed a high level of genetic similarity over a substantial geographic range, suggesting that they may represent conspecific populations. The taxonomic and biogeographic implications of these findings for Macrobrachium in Australia are discussed.

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In order to facilitate the better management of river basin resources, the Glenelg-Hopkins region in south-east Australia required an accurate and up to date land use map. Land use has a major impact on Australia's natural resources including its soil, water, flora and fauna and plays a major role in determining basin health. Inappropriate land use and practices have contributed to extensive dryland salinity and water quality problems. Land use data is often required for environmental models and in most cases the reliability of model outputs is dependent on the spatial detail and accuracy of the land use mapping. This paper examines methods to obtain an up to date land use map and a detailed accuracy assessment using Landsat ETM+ data for a regional basin. A multi-source based approach allowed the collection of 4817 ground truth data points from the field investigation. This enabled researchers to (i) incorporate a full range of information into digital image analysis with significant improvements in accuracy and (ii) hold sufficient independent references for an accurate error assessment. Classification accuracy was significantly improved using a stratification design, in which the region is sub-divided into smaller homogenous areas as opposed to a full scene classification technique. The overall classification accuracy was 84% (KHAT= 0.833) for the stratified approach compared to 76% (KHAT= 0.743) for the full scene classification. Effective assessment, planning and management of basins are dependent on a sound knowledge of the distribution and variability of land use.

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Artificial neural networks (ANN) are increasingly used to solve many problems related to pattern recognition and object classification. In this paper, we report on a study using artificial neural networks to classify two kinds of animal fibers: merino and mohair. We have developed two different models, one extracting nine scale parameters with image processing, and the other using an unsupervised artificial neural network to extract features automatically, which are determined in accordance with the complexity of the scale structure and the accuracy of the model. Although the first model can achieve higher accuracy, it requires more effort for image processing and more prior knowledge, since the accuracy of the ANN largely depends on the parameters selected. The second model is more robust than the first, since only raw images are used. Because only ordinary optical images taken with a microscope are employed, we can use the approach for many textile applications without expensive equipment such as scanning electron microscopy.


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A number of methods for automated objective ratings of fabric pilling based on image analysis are described in the literature. The periodic structure of fabrics makes them suitable candidates for frequency domain analysis. We propose a new method of frequency domain analysis based on the two-dimensional discrete wavelet transform to objectively measure pilling intensity in sample images. We present a preliminary evaluation of the proposed method based on analysis of two series of standard pilling evaluation test images. The initial results suggest that the proposed method is feasible, and that the ability of the method to discriminate between levels of pilling intensity depends on the wavelet analysis scale being closely matched to the fabric interyarn pitch. We also present a heuristic method for optimal selection of an analysis wavelet and associated analysis scale.


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The evolutionary history and classification of the palaemonid shrimps has been the subject of constant speculation and debate. At present, all major systematic treatments have been based on morphological characteristics. To help resolve the phylogenetic relationships, and thus enable the creation of a classification system that reflects evolutionary history, a region of the 16S mitochondrial rRNA gene was sequenced for a number of Australian Palaemonidae. The resulting phylogenetic analyses indicated the presence of major anomalies in the current classification of Australian Palaemonidae. Significantly, three species belonging to three separate genera, Macrobrachium intermedium, Palaemon serenus, and Palaemonetes australis, are closely related, with genetic differences more characteristic with that of congeneric species. The results also demonstrate non-monophyly in Australian palaemonids with respect to both Palaemonetes and Macrobrachium.

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A new algorithm for the Petrov classification of the Weyl tensor is introduced. It is similar to the Letniowski-McLenaghan algorithm [1] when someof the ¥'s are zero, but offers a completely new approach when all of the ¥'s are nonzero. In all cases, new code in Maple has been implemented.

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A new algorithm, based on the introduction of new spinor quantities, for the Segre classification of the trace-free Ricci tensor is presented. It is capable of automatically distinguishing between the two Segre types [1,1(11)] and [(1,1)11] where all other known algorithms fail to do so.

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Previously, we proposed a new method of frequency domain analysis based on the two-dimensional discrete wavelet transform to objectively measure pilling intensity in sample fabric images. We have further evaluated this method, and our results indicate that it is robust to small horizontal and/or vertical translations and to significant variations in the brightness of the image under analysis, and is sensitive to rotation and to dilation of the image. These results suggest that as long as precautions are taken to ensure fabric test samples are imaged under consistent conditions of weave/knit pattern alignment (rotation) and apparent interyarn pitch (dilation), the method will yield repeatable results.


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Aim: To investigate the phylogeographic structure of the widespread freshwater prawn, Macrobrachium australiense, within and between major Australian drainage basins using mitochondrial sequence data. This will enable the investigation of historical connections between major drainages and examination of hypotheses of biogeographic associations among Australian freshwater basins.

Location: Inland, eastern and northern Australia.

Methods: Sequencing 16S rRNA and ATPase 6 protein coding mitochondrial DNA genes from M. australiense from 19 locations from inland, eastern and northern Australia.

Results: Within drainage basins, haplotype trees are monophyletic, with the exception of the Finke River from the Lake Eyre Basin. Macrobrachium australiense from the two main inland drainages, the Murray–Darling and Lake Eyre Basin are divergent from each other and do not form a monophyletic group, instead the Murray–Darling Basin haplotypes clade with eastern coastal haplotypes. Haplotypes from neighbouring eastern coastal drainages were found to be quite divergent from each other.

Main conclusions: The phylogeographic relationships among M. australiense suggest that the two major inland drainages, the Murray–Darling Basin and the Lake Eyre Basin, are not biogeographically closely associated to each other. Instead the Murray–Darling Basin is more closely allied with the eastern coastal drainages across the Great Dividing Range. Despite their proximity the neighbouring southeast Queensland coastal Mary and Brisbane Rivers are also biogeographically divergent from each other. The results also indicate that the Finke River appears to have been isolated from the remainder of the Lake Eyre Basin catchment for a significant period of time.

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The evolutionary relationships of the freshwater prawn genus Macrobrachium are obscure. Members of this genus are widely distributed across tropical and subtropical regions. The phylogenetic relationships among the seven endemic and six non-endemic Australian Macrobrachium, along with five non-Australian species, were inferred from the mitochondrial 16S rRNA gene sequences. Methods of analysis yielded phylogenetic trees of differing topologies; however, none supported a monophyletic origin for endemic Australian Macrobrachium. Enforced monophyly of a single origin of endemic Macrobrachium was statistically tested and rejected. These results support the view that the endemic Australian Macrobrachium arose from multiple origins. Previous biogeographical hypotheses related to the radiation of Macrobrachium into Australia are re-examined in the context of these results.

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The freshwater shrimp Macrobrachium australiense is distributed throughout the majority of inland, north-west, north-east and eastern drainages. Owing to the large amount of morphological divergence, both between and within catchments, this species has proven to be taxonomically difficult and, until recently, consisted of three separate species, each with subsequent subspecies. This study uses nucleotide sequences from the 16S rRNA mitochondrial gene region to investigate the genetic relationships between populations and confirm the taxonomic status of M. australiense. The results from sequencing an approximately 450-bp fragment from this gene region from M. australiense sampled from 12 locations across inland, eastern and northern Australia identified very little variation. The variation found between 16S M. australiense haplotypes is much less than that found between Macrobrachium species, indicating that it is in fact a single species. The results are concordant with a recent morphological revision of Australian species in which nominal taxa of the M. australiense complex were synonymised.

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Comprehensive classification systems to accurately account for lands managed for biodiversity conservation, are an essential component of conservation planning and policy. The current international classification systems for lands managed for nature conservation are reviewed, with a particular emphasis on Australia. The need for a broader, all-encompassing, categorisation of lands managed for conservation is presented and a proposed broader categorisation system is developed—the Conservation Lands Classification. This classification system has the advantage of incorporating data on both tenure and protection mechanisms and has been applied in this paper using conservation lands in three Australian jurisdictions as examples. It is envisaged that this method of classification has the potential to significantly improve the ability to measure current and future trends in nature conservation across all land types at a variety of scales and hence is put forward in order to stimulate discussion on this important topic.

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A national approach to the conservation of biodiversity in Australia’s freshwater ecosystems is a high priority. This requires a consistent and comprehensive system for the classification, inventory, and assessment of wetland ecosystems. This paper, using the State of Victoria as a case study, compares two classification systems that are commonly utilized to delineate and map wetlands—one based on hydrology (Victorian Wetland Database [VWD]) and one based on indigenous vegetation types and other natural features (Ecological Vegetation Classes [EVC]). We evaluated the extent of EVC mapping of wetlands relative to the VWD classification system using a number of datasets within a geographical information system. There were significant differences in the coverage of extant EVCs across bioregions, different-sized wetlands, and VWD wetland types. Resultant depletion levels were markedly different when examined using the two systems, with depletion levels, and therefore perceived conservation status, of EVCs being significantly higher. Although there is little doubt that many wetland ecosystems in Victoria are in fact threatened, the extent of this threat cannot accurately be determined by relying on the EVC mapping as it currently stands. The study highlighted the significant impact wetland classification methods have in determining the conservation status of freshwater ecosystems.