3,693 research outputs found
Plan shewing mining companies at Mount Lyell, west coast, Tasmania [cartographic material].
No full textMap showing mining leases and their extent. Relief shown by hachures.; 'Note - This map has been specially compiled for G. A. Lawson, 90 Queen Street, Melbourne'.; From: The past and present position of the mineral industry on the West Coast, Tasmania / G.A. Lawson.; Ferguson, J.A. Bibliography of Australia, 11491; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.map-rm2731
The Greece of the Greeks: By G.A. Perdicaris, A.M. Late Consul of the United Stats at Athens, in two volumes. New-York: Paine and Burgess, 1845.
No full textIntroduction: (introductory) by the authorDedication: by the author to those who are interested in the Fate of GreecePagination: PP21+293P, PP8+300P+1PPVolumes: 2Edition:1stText Genre:Prose / Journa
Breeding bird populations of Irish peatlands : capsule peatlands are very important habitats for birds despite low species diversity
No full textAims to describe the variation in breeding bird populations that occur on different types of Irish peatlands and their associated habitat characteristics.
Methods: Bird abundance and diversity were compared between four peatland habitat types: fens; raised bogs; Atlantic blanket bogs; and montane blanket bogs at twelve study sites using transects. Various measures of habitat quality were also taken at each location.
Results: Only 21 species were recorded during the study with Meadow Pipit Anthus pratensis and Sky Lark Alauda arvensis accounting for over 80% of all birds recorded. Fens had greater bird species diversity and densities than the other three peatland types. Raised bogs, Atlantic blanket bogs and montane blanket bogs were very similar in terms of their avian diversity. Each of the recorded bird species were associated with different aspects of the peatland habitat.
Conclusion: This study shows that despite the relatively low avian species diversity of Irish peatlands, they are of enormous conservation value due to the presence of species of high conservation concern such as Red Grouse (Willow Ptarmigan) Lagopus lagopus and Eurasian Curlew Numenius arquata.Other funderEnvironmental Protection Agency (EPA)ke, ab, sp, li - TS 26.04.1
Bird communities following high-severity fire: Response to single and repeat fires in a mixed-evergreen forest, Oregon, USA
No full textFire is a widespread natural disturbance agent in most conifer-dominated forests. In light of climate change and the effects of fire exclusion, single and repeated high-severity (stand-replacement) fires have become prominent land management issues. We studied bird communities using point counting in the Klamath-Siskiyou ecoregion of Oregon, USA at various points in time after one or two high-severity fires. Time points included 2 and 3 years after a single fire, 17 and 18 years after a single fire, 2 and 3 years after a repeat fire (15 year interval between fires), and >100 years since stand-replacement fire (mature/old-growth forest). Avian species richness did not differ significantly among habitats. Bird density was highest 17 and 18 years after fire, lowest 2 years after fire, and intermediate in repeat burns and unburned forest. Bird community composition varied significantly with habitat type (A = 0.24, P < 0.0001) with two distinct gradients in species composition relating to tree structure (live to dead) and shrub stature. Using indicator species analysis, repeat burns were characterized by shrub-nesting and ground-foraging bird species while unburned mature forests were characterized by conifer-nesting and foliage-gleaning species. Bird density was not related to snag basal area but was positively related to shrub height. Contrary to expectations, repeated high-severity fire did not reduce species richness, and bird densities were greater in repeat burns than in once-burned habitats. Broad-leaved hardwoods and shrubs appear to play a major role in structuring avian communities in the Klamath-Siskiyou region. In light of these results, extended periods of early seral broadleaf dominance and short-interval high-severity fires may be important to the conservation of avian biodiversity
Automatic sign language recognition inspired by human sign perception
No full textAutomatic sign language recognition is a relatively new field of research (since ca. 1990). Its objectives are to automatically analyze sign language utterances. There are several issues within the research area that merit investigation: how to capture the utterances (cameras, magnetic sensors, instrumented gloves), how to extract interesting information from the captured data, and how to classify signs or sentences automatically using the extracted information. These issues are of an immediate and basic nature, and must be solved before any automatic recognition of sign language can be achieved. But other issues, pertaining to the nature of sign language and human recognition, are no less interesting: which elements of a sign are important for the meaning of an utterance? How do consecutive signs influence one another? Why are certain types of variation unimportant while others change the meaning of the sign? Automatic sign language recognition has, until recently, mostly focused on the first set of issues. In this thesis, we attempt to integrate knowledge about sign languages and human sign recognition into the automatic sign recognition process. Research on the (psycho)linguistics of sign languages is itself quite young (since ca. 1960), and many questions as yet unanswered. For this reason, we conduct our own studies of human sign language recognition. The knowledge gained from these experiments is applied in an existing automatic sign language recognition system. The thesis is divided into two parts: the first part describes the experiments conducted with human signers, the second part describes experiments investigating the possibilities of integrating such knowledge in the automatic recognizer. This recognizer is meant to be used in an interactive environment for young children to practice sign language vocabulary. For this reason, it is vision-based (which is unobtrusive), and only handles isolated signs. The experiments in part I of the thesis investigate the information content of various sign elements: fragments of a sign in time (chapter 2), and the sign aspects handshape and hand orientation (chapter 3). In time, the central phase of a sign is the most informative one, equally informative to the entire sign. Recognition based on other phases is also possible to a certain extent, and the transition from the preparation phase to the central phase appears to be a salient moment. As for the aspects, the aspect handshape proves more useful for recognition than hand orientation. Chapter 4 gives an overview of the human recognition research and discusses possibilities for application. In part II, the possibilities of utilizing the results of part I in the recognition system are investigated. Chapter 5 describes the addition of the handshape feature to the system (which chapter 3 showed to be the most interesting feature to add). Adding handshape gives a small improvement in the recognition performance. In chapter 6, the salience of the sign fragments used in chapter 2 for the automatic recognizer is investigated. The central phase proves to be the most informative one, as it was for human signers. Chapter 7 describes experiments in which a small set of frames is used to represent a sign. The results show a deterioration in recognition performance. Strict demands on the correctness of the remaining frames are probably partly responsible for the performance decrease. In conclusion, we can say that applying human knowledge in automatic sign language recognition is a complex task. Conclusions about human sign recognition do not necessarily hold for the automatic recognizer as well. The most important obstacles for utilizing information successfully seem to be: 1) data acquisition: computer vision is not as accomplished as human observers in capturing the complex, dynamic hand and face motions that form sign language. This means that information that is present in a sign movement for a human being may not be (correctly) observed by an automatic vision analysis system. Thus, the data that humans work with is not necessarily identical to the data the recognizer works with, and this may cause techniques that are successful for human signers to fail in the automatic system. And 2) differences in basic system architecture. Research into human sign recognition is still ongoing, there is no clear model of human sign recognition yet. This makes it more difficult to translate observations from human sign recognition to the automatic recognizer: human signers may use techniques that are not compatible with the current architecture of the recognizer. For example: human signers may process aspects independently. If the recognition system processes all data as a single stream, then such a technique cannot be implemented. A more thorough understanding of human sign recognition, more sophisticated computer vision techniques, and a close co-operation between the fields of automatic sign language recognition and human sign perception, seems the best way to overcome these obstacles.MediamaticsElectrical Engineering, Mathematics and Computer Scienc
The organization of tip links and stereocilia on hair cells of bird and lizard basilar papillae
No full textAuditory papillae from three species of bird (pigeon, starling, and chick), and two species of European lizard (Podarcis murolis and Podarcis sic&) were examined by scanning electron microscopy. Hair bundles from all papillae showed tip links oriented along the direction of gradation in heights of the stereocilia (i.e. parallel to the hair-cell axis of bilateral symmetry, and so parallel to the
excitato~-i~bito~ axis for m~hanotransduction). This orientation was seen irrespective of the overall orientation of the hair bundle within the papilla. The stereocilia formed columns, joined by the tip links, which ran parallel to the hair-cell axis of bilateral symmetry. The stereocilia within the same column tended to stay together, while those in different columns tended to separate during preparation, In many columns ail the stereocilia tended to be a little taller, or a little shorter, than the equivalent stereocilia in adjacent columns, suggesting that all the stereocilia within one column had been affected by a common height determinant during development. In addition, links running laterally between stereocilia were seen, in a band near the base of the stereocilia. The results are consistent with the hypothesis that tip links are a universal feature of mechano-transducing acousticolateral hair cells, and that
they are involved in sensory transduction. The results also support suggestions that the tip links may play a role in determining the heights of the stereocilia during development
How does the economic risk aversion affect biodiversity?
No full textThe present paper analyses the role played by risk aversion in the reconciling of agricultural income and biodiversity. A bio-economic mode which articulates bird community dynamics and representative farmers selecting land uses within an uncertain macro-economic context is developed. It is spatialized and calibrated at a regional scale for France through national databases. The impact of risk aversion is assessed on economic, agricultural and ecological outputs through projections at the 2050 horizon. A high enough aversion proves sufficient to promote global bio-economic performance and multi-functional agriculture. This occurs through a diversification mechanism on regional land-uses. Spatial disparities however suggest that public incentives could be necessary to reinforce the diversification and bio-economic effectiveness.Agriculture, Aversion, Bio-economic modeling, Bird, Biodiversity, Diversification, Public good, Spatial
Ecology, impacts and management of pest birds
No full textPests can impact significantly upon the economy, the environment and on human and animal health. However, for pest birds there are surprisingly few studies of these impacts and how to reduce them. The aim of this thesis is to advance our understanding of the ecology, impacts, and management of pest birds using case studies for each of the three main impacts.
In considering economic impacts I estimate pest bird abundance, describe a novel method for measuring bird damage, and evaluate the efficacy of lethal and non-lethal methods in vineyards and orchards. Using data across 185 property years, netting was found to be the most effective in reducing bird damage. Shooting was not as effective but was one-third of the cost and had 13% lower damage compared with nil-treatments. Scaring with electronic devices and visual deterrents had no effect on bird damage. Despite their widespread use, lethal methods had limited effectiveness for reducing pest abundance.
In considering environmental impacts introduced mallards on Lord Howe Island were used as a case study. Phenotypic characteristics suggest that mallards have supplanted the native Pacific black duck on Lord Howe Island. Management alternatives are evaluated and discussed.
In considering health-related impacts wild birds and avian influenza in Australia was used as a case study. Here, the ecology of Australia’s Anseriformes, and the epidemiology, modes of transmission, and the factors influencing the prevalence of avian influenza in Australia’s wild birds are investigated. Risk profiles to improve the efficiency and relevance of wild-bird surveillance are also provided.
The case studies presented demonstrate that an understanding of a pest’s ecology, efficient measures of impacts, and thorough evaluations of surveillance and management strategies are essential for effectively managing their economic, environmental and health-related impacts
Characteristics of breeding passerine communities at Earlshallmuir and Tentsmuir, North-East Fife
No full textThe literature pertaining to a variety of methods for estimating the
abundances of songbirds is reviewed, and the use of two of the main methods -
mapping and transects - is described and discussed. The mapping method is
found to be the most efficient and reliable in the context of the present
study, and work elsewhere in the British Isles suggests that the method
has wide applicability in the region.
Various methods for describing the habitats in which birds occur are discussed.
In the present study the method chosen involved measuring various
parameters of the vegetation within a limited area at each of several
sampling points in five study plots in North-east Fife. It proved a useful
method in the habitats studied - dune grassland, commercial and semi-natural
coniferous woodlands, and deciduous scrub and mature woodland - and results
of the vegetation sampling are discussed in terms of habitat structure and
succession, and in the relationship of this structure to the breeding bird
communities.
The composition of these communities in the study plots is described, as
are the changes over the three breeding seasons 1979-1981, which followed
on from a meteorologically "hard" winter. Over the study period there was
an overall increase in the populations of all five study plots, and this
increase was greatest in the poorest habitat - the dune grassland - and
least in the richest habitat - the mature deciduous woodland. Using indices
to compare the study plots a major difference was found between the grassland
plot and all four woodland plots, amongst which the two coniferous ones were
most similar.
Of the more abundant bird species, Robin, Song Thrush and Coal Tit were
more prevalent in coniferous habitats; Willow Warbler and Blue Tit were
more prevalent in the deciduous habitats. In relation to habitat structure,
the more diverse bird communities were found in the more complex habitats,
and there was evidence of succession in the bird communities concomitant
with habitat succession.
The present study is one of very few in Europe involving woodland habitats
especially of a commercial nature near sea-level, and it was found that
the four woodland study plots were rich in terms of the diversities and
densities of their passerine breeding populations when compared with other
European studies
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