38 resultados para Migratory locust.


Relevância:

10.00% 10.00%

Publicador:

Resumo:

In parts of the Indo-Pacific, large-scale exploitation of the green turtle Chelonia mydas continues to pose a serious threat to the persistence of this species; yet very few studies have assessed the pattern and extent of the impact of such harvests. We used demographic and genetic data in an age-based model to investigate the viability of an exploited green turtle stock from Aru, south-east Indonesia. We found that populations are decreasing under current exploitation pressures. The effects of increasingly severe exploitation activities at foraging and nesting habitat varied depending on the migratory patterns of the stock. Our model predicted a rapid decline of the Aru stock in Indonesia under local exploitation pressure and a shift in the genetic composition of the stock. We used the model to investigate the influence of different types of conservation actions on the persistence of the Aru stock. The results show that local management actions such as nest protection and reducing harvests of adult nesting and foraging turtles can have considerable conservation outcomes and result in the long-term persistence of genetically distinct management units. © 2010 The Authors. Animal Conservation © 2010 The Zoological Society of London.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Great Sandy Region (incorporating Fraser Island and the Cooloola sand-mass), south-east Queensland, contains a significant area of Ramsar-listed coastal wetlands, including the globally important patterned fen complexes. These mires form an elaborate network of pools surrounded by vegetated peat ridges and are the only known subtropical, Southern Hemisphere examples, with wetlands of this type typically located in high northern latitudes. Sedimentological, palynological and charcoal analysis from the Wathumba and Moon Point complexes on Fraser Island indicate two periods of swamp formation (that may contain patterned fens), one commencing at 12 000 years ago (Moon Point) and the other ~4300 years ago (Wathumba). Wetland formation and development is thought to be related to a combination of biological and hydrological processes with the dominant peat-forming rush, Empodisma minus, being an important component of both patterned and non-patterned mires within the region. In contrast to Northern Hemisphere paludifying systems, the patterning appears to initiate at the start of wetland development or as part of an infilling process. The wetlands dominated by E. minus are highly resilient to disturbance, particularly burning and sea level alterations, and appear to form important refuge areas for amphibians, fish and birds (both non-migratory and migratory) over thousands of years.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This thesis examines the extent of which economic instruments can be used to minimise environmental damage in the coastal and marine environments, and the role of offsets to compensate for residual damage. Economic principles are used to review current command and control systems, potential incentive based mechanisms, and the development of appropriate offsets. Implementing offsets in the marine environment has a number of challenges, so alternative approaches may be necessary. The study finds that offsets in areas remote from the initial impact, or even to protect different species, may be acceptable provided they result in greater conservation benefits than the standard like-for-like offset. This study is particularly relevant for the design of offsets in the coastal and marine environments where there is limited scope for like-for-like offsets.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Summary: This book explores the fascinating topic of heritage language learning, looking in particular at Chinese Australians' learning of Chinese. The author studies the investment, challenges and benefits of heritage language learning across varied contexts including school, work, home and in the community. The book investigates how Chinese Australians navigate and negotiate their Chineseness and how resources are used to support their learning. The book is based on a mixed methods study which uses Bourdieu's sociological theory, and offers implications for sociologists of language and education, Chinese heritage language learners and teachers, as well as language and cultural policy makers. Review: This book is a compelling account of the habitus of Chineseness in a world of mobility. It offers up a plethora of insights into the implication of heritage language learning in the constitution of Chinese identity; it makes available a sophisticated mixed methods approach for using the thinking tools of Pierre Bourdieu; it adds to these tools a nuanced cultural dimension. Karen Dooley, Queensland University of Technology, Australia In our increasingly trans-migratory world, language can be central to cultural identity. Dr Mu’s research breaks new ground by adapting Bourdieu’s insights to examine how cultural identity (‘Chinese-ness’) is linguistically learned and practiced in Australia. His remarkable book will interest educators and researchers grappling with how language pertains to identity. Tom Strong, University of Calgary, Canada A thought-provoking, highly engaging work that has deftly shown how Bourdieusian framework can be applied in the research field of literacy education and Heritage Language learning. A must-read for those interested in overseas Chinese communities and Heritage Language learning across various immigrant communities in general! Liang Du, Beijing Normal University, China

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Electrospun nanofiber meshes have emerged as a new generation of scaffold membranes possessing a number of features suitable for tissue regeneration. One of these features is the flexibility to modify their structure and composition to orchestrate specific cellular responses. In this study, we investigated the effects of nanofiber orientation and surface functionalization on human mesenchymal stem cell (hMSC) migration and osteogenic differentiation. We used an in vitro model to examine hMSC migration into a cell-free zone on nanofiber meshes and mitomycin C treatment to assess the contribution of proliferation to the observed migration. Poly (ɛ-caprolactone) meshes with oriented topography were created by electrospinning aligned nanofibers on a rotating mandrel, while randomly oriented controls were collected on a stationary collector. Both aligned and random meshes were coated with a triple-helical, type I collagen-mimetic peptide, containing the glycine-phenylalanine-hydroxyproline-glycine-glutamate-arginine (GFOGER) motif. Our results indicate that nanofiber GFOGER peptide functionalization and orientation modulate cellular behavior, individually, and in combination. GFOGER significantly enhanced the migration, proliferation, and osteogenic differentiation of hMSCs on nanofiber meshes. Aligned nanofiber meshes displayed increased cell migration along the direction of fiber orientation compared to random meshes; however, fiber alignment did not influence osteogenic differentiation. Compared to each other, GFOGER coating resulted in a higher proliferation-driven cell migration, whereas fiber orientation appeared to generate a larger direct migratory effect. This study demonstrates that peptide surface modification and topographical cues associated with fiber alignment can be used to direct cellular behavior on nanofiber mesh scaffolds, which may be exploited for tissue regeneration.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Objectives: Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous tumour type which necessitates multiple invitro models to attain an appreciation of its multiple subtypes. The phenomenon of epithelial-mesenchymal transition (EMT) isimportant to the development of a metastatic cancer cell phenotype being relevant to the ability of cancer cells to intravasate intovasculature and to invade tissues. The role of EMT in human papilloma virus (HPV) positive HNSCC is not well understood. Thispaper aims to characterize seven HNSCC cell lines (FaDu, SCC-25, SCC-15, CAL27, RPMI2650) including two new HPV-16positive HNSCC cell lines (UD-SCC2, 93-VU-147T) for their epithelial and mesenchymal properties. Materials and methods: A panel of HNSCC cell lines from multiple head and neck anatomical sites were profiled for basalexpression of epithelial and mesenchymal characteristics at mRNA, protein and functional levels (proliferative, migratory andinvasive properties). Furthermore, 3D spheroid forming capabilities were investigated. Results: We found that the HPV-16 positive cell line, in particular UD-SCC2 demonstrated a more invasive and mesenchymalphenotype at the molecular and functional levels suggesting HPV infection may mediate some of these cellular properties.Moreover, HPV-negative cell lines were not strictly epithelial presenting with a dynamic range of expression. Conclusions: This study presents the molecular and phenotypic diversity of HNSCC cell lines. It highlights the need formore studies in this field and a scoring system where HNSCC cell lines are ranked according to their respective epithelial andmesenchymal nature. This data will be useful to anyone modelling HNSCC behaviour, providing a molecular context which willenable them to decipher cell phenotypes and to develop therapies which block EMT progression.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The interactive artwork Temporal arose from a series of art-science investigations with some of Australia’s leading flying fox ecologists. It was designed as a gently evolving meditation upon the complex, periodic processes that mark Australia’s often irregular seasonal changes. In turn these changes directly govern the migratory movements of Australia’s keystone pollinating mammals - the mega bats (Flying Foxes). Temporal further called attention to our increasing capacity to profoundly disturb these partners within Australia’s complex, life-supporting systems

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This thesis brings together different scientific and engineering disciplines, as well as current legislation, on the subject of unwanted night-time lighting effects on humans and the biosphere. The assessment criteria of Australian Standard AS4282-1997 Control of the obtrusive effects of outdoor lighting are reviewed and criteria incorporating the quantity, quality, spectral composition of light, and exposure time, are proposed to improve light engineering practice. The immediate direct concerns of humans are considered as well as the effects on biota generally in the environment, particularly as outdoor artificial lighting proliferation has the potential to change the environment for human habitation in the longer term.