3,530 research outputs found
A review of water quality issues influencing the habitat quality in dugong protection areas
In August 1997, the Commonwealth and Queensland Governments established 16
coastal Dugong Protection Areas (DPAs) to reduce the threat of mesh nets to dugongs
(Dugong dugon). The DPAs are situated in the Central and Mackay/Capricorn
Sections of the Great Barrier Reef Marine Park (GBRMP) and the Hervey BayâGreat
Sandy Strait region (Figure 1), and were enacted by Regulation No. 11 (1997) under
the Queensland Fisheries Act 1994 and the Nature Conservation (Dugong) Conservation
Plan 1999 under the Nature Conservation Act 1992. The establishment of DPAs was
considered the key strategy to address the rapid decline of the Great Barrier Reef
(GBR) dugong population south of Cooktown
Report on status and trends of water quality and ecosystem health in the Great Barrier Reef World Heritage Area
Contributors: Rob Coles, Steve Delean, Miles Furnas, Len McKenzie, Munro Mortimer, Jochen Muller, Andrew Negri, Hugh Sweatman and Angus Thompson
Division of the bivalved mollusca described by James Dwight Dana 1847-1849 from the Permian of eastern Australia
The Permian Bivalvia collected and described by J.D. Dana (1847, 1849) from the Sydney Basin, New South Wales, Australia are revised and illustrated from the collections at the Smithsonian Institution, Washington, D.C. The morphology of some genera erected by Dana (1847) is clarified, and some of the obscure species, such as Pecten mitis, Astarte gemma, and Pholadomya glendonensis are redescribed. Statistical summaries are presented for some of the species with controversial limits, such as Pyramus myiformis Dana, Notomya securiformis MâCoy, and various species of Astartila. Newly proposed names are Polidevcia cryptica for Nucula concinna Dana, 1847 not Nucula concinna Sowerby, 1836; and Astartila runnegari for Pachydomus ovalis MâCoy, November 1847, not Pachydomus ovalis Sowerby, February 1847, the latter new name a subjective synonym of Astartila intrepida Dana
Tannakian approach to linear differential algebraic groups
Tannaka's Theorem states that a linear algebraic group G is determined by the
category of finite dimensional G-modules and the forgetful functor. We extend
this result to linear differential algebraic groups by introducing a category
corresponding to their representations and show how this category determines
such a group.Comment: 31 pages; corrected misprint
First Annual Marine Monitoring Programme Report September 2005
This report provides an overview of the development of the Marine Monitoring Programme, a description of each component
of the programme, an overview of the current status of the components of the programme and an outline of the
implementation of the programme as at June 2005. This report is GBRMPAâs inaugural report for the Marine Monitoring
Programme. The structure of this report will form the basis of Annual Reports from the GBRMPA for the life of the Reef Water
Quality Protection Plan Marine Monitoring Programme
Synonymy and stratigraphic ranges of Belemnopsis in the Heterian and Ohauan Stages (Callovian-Tithonian), southwest Auckland, New Zealand.
Belemnopsis stevensi, Belemnopsis maccrawi, and Belemnopsis sp. A (Challinor 1979a) are synonymous; B. stevensi has priority. New belemnite material from Kawhia Harbour and Port Waikato, together with graphical study methods, indicates that many small fragmentary specimens associated with B. stevensi in the lower part of its stratigraphic range are probably the same taxon. B. stevensi has been found only in the Middle and Upper Heterian Stage (Lower Kimmeridgian) at Kawhia and only in the Lower Ohauan Stage (Upper Kimmeridgian) at Port Waikato. This apparently disjunct distribution is attributed to poor exposure in the relevant sections. Belemnopsis kiwiensis n.sp., Belemnopsis cf. sp. B, Belemnopsis sp. B, Belemnopsis sp. D, and Belemnopsis spp. are associated with B. stevensi near the lowest known point in its stratigraphic range. The distribution of stratigraphically useful belemnites within the Heterian and Ohauan Stages is: Conodicoelites spp. (Lower Heterian; correlated with Lower Callovian); Belemnopsis annae (Lower and Middle Heterian; Lower Callovian/Lower Kimmeridgian); Belemnopsis stevensi (Middle Heterian/Lower Ohauan; Kimmeridgian); Belemnopsis keari (Upper Heterian; Kimmeridgian); Belemnopsis trechmanni (Upper Ohauan; Upper Kimmeridgian/Middle Tithonian). The apparently extreme range of Belemnopsis annae remains unexplained. Klondyke Sandstone (new) is recognised as the basal member of Moewaka Formation (Port Waikato area)
A Light, Transmission and Scanning Electron Microscope Study of Snuff-Treated Hamster Cheek Pouch Epithelium
The effects of smokeless tobacco (snuff) on hamster cheek mucosa were studied by light microscopy, transmission (TEM) and scanning electron microscopy (SEM). Two grams of commercially available smokeless tobacco were placed into the blind end of the right cheek pouch of each experimental animal, once a day and five days a week for 24 months. The control animals did not receive smokeless tobacco. After 24 months treatment with smokeless tobacco, hamster cheek mucosal epithelium lost its translucency and had become whitish in color. By light microscopy hyperorthokeratosis, prominent granular cell layers with increased keratohyalin granules and hyperplasia were seen. At the ultrastructural level, wider intercellular spaces filled with microvilli, numerous shorter desmosomes, many thin tonofilament bundles, increased number of mitochondria, membrane coating granules and keratohyalin granules were seen in snuff-treated epithelium. The changes in the surface of the epithelium as seen by SEM were the development of an irregular arrangement of the microridges and the disappearance of the normal honeycomb pattern. The microridges were irregular, widened and surrounded the irregular elongated pits. Some smooth areas without microridges and pits were also seen.
The long-term histological, TEM and SEM changes induced by smokeless tobacco treatment of the epithelium are well correlated with each other and were similar to those reported in human leukoplakia without dyskeratosis. They imply changes of pathological response resulting from topically applied snuff
Variational approximation for mixtures of linear mixed models
Mixtures of linear mixed models (MLMMs) are useful for clustering grouped
data and can be estimated by likelihood maximization through the EM algorithm.
The conventional approach to determining a suitable number of components is to
compare different mixture models using penalized log-likelihood criteria such
as BIC.We propose fitting MLMMs with variational methods which can perform
parameter estimation and model selection simultaneously. A variational
approximation is described where the variational lower bound and parameter
updates are in closed form, allowing fast evaluation. A new variational greedy
algorithm is developed for model selection and learning of the mixture
components. This approach allows an automatic initialization of the algorithm
and returns a plausible number of mixture components automatically. In cases of
weak identifiability of certain model parameters, we use hierarchical centering
to reparametrize the model and show empirically that there is a gain in
efficiency by variational algorithms similar to that in MCMC algorithms.
Related to this, we prove that the approximate rate of convergence of
variational algorithms by Gaussian approximation is equal to that of the
corresponding Gibbs sampler which suggests that reparametrizations can lead to
improved convergence in variational algorithms as well.Comment: 36 pages, 5 figures, 2 tables, submitted to JCG
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