995 resultados para Internet in education -- Australia


Relevância:

100.00% 100.00%

Publicador:

Resumo:

American bison grow a thick coat of fibres which assists them to withstand severe climatic conditions. Bison fibre was traditionally used in textiles by native North Americans. This study aimed to quantify the production, fibre attributes and dehairing processing of bison fibre produced from bison grazed in north-eastern Victoria. Three age/sex classes were sampled (n = 16) at seven body positions in spring. The fibre growing area was measured. Fibre was tested for diameter distribution, clean washing yield, proportion of fine fibres <36µm and fine fibre length, and processed by cashmere dehairing. Bison were 12 years of age, liveweights 160450 kg and had mean fibre growing area of 1.4 m2. They produced an average 1184 g (range 5301640 g) of fine fibre with mean fibre diameter 18.5µm, clean washing yield 76.5%, wax content 9.8%, suint content 14.5%, clean fine fibre yield 56.4%, fine fibre length 37 mm and fibre curvature was 93/mm. Mid-side fibre had a crimp frequency of 6.5/cm and mean resistance to compression of 6.6 kPa. Fibre had a tenacity of 8.7 cN/tex and an extension of 39.3%. Restricted maximum likelihood mixed model analysis showed age/sex class and sampling site significantly affected all fibre attributes. Finer and longer fibre was produced in anterior sites and in younger bison. Fibre curvature declined 5.3°/mm for each 1-µm increase in mean fibre diameter. Dehaired fibre had a mean fibre diameter of 17.8 µm and mid-length of 28 mm, suitable for woollen spinning. The production by bison of coats containing significant amounts of fibre indicates that careful harvesting of fibre could form an important source of income in bison enterprises.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The effect of separation by biogeographic features followed by secondary contact can blur taxonomic boundaries and produce complex genetic signatures. We analyzed population structure and gene flow across the range of the long-tailed finch (Poephila acuticauda) in northern Australia (1) to test the hypothesis that Ord Arid Intrusion acted as the causative barrier that led to divergence of P. acuticauda subspecies, (2) to determine whether genetic data support the presence of a gradual cline across the range or a sudden shift, both of which have been suggested based on morphological data, and (3) to estimate levels of contemporary gene flow within this species complex. We collected samples from 302 individuals from 10 localities. Analyses of 12 microsatellite loci and sequence data from 333 base pairs of the mitochondrial control region were used to estimate population structure and gene flow, using analysis of molecular variance (AMOVA), haplotype network analysis, frequency statistics, and clustering methods. Mitochondrial sequence data indicated the presence of three genetic groups (regions) across the range of P. acuticauda. Genetic diversity was highest in the east and lowest in the west. The Ord Arid Intrusion appears to have functioned as a biogeographic barrier in the past, according to mtDNA evidence presented here and evidence from previous studies. The absence of isolation by distance between adjacent regions and the lack of population genetic structure of mtDNA within regions indicates that genetic changes across the range of P. acuticauda subspecies are characterized by discrete breaks between regions. While microsatellite data indicate a complete absence of genetic structure across this species’ range, it appears unlikely that this results from high levels of gene flow. Mitochondrial data do not support the presence of contemporary gene flow across the range of this species.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Although interest in the ecological impacts of invasive species has largely focused on negative effects, some native taxa may benefit from invader arrival. In tropical Australia, invasive cane toads (Bufo marinus) have fatally poisoned many native predators (e.g., marsupials, crocodiles, lizards) that attempt to ingest the toxic anurans, but birds appear to be more resistant to toad toxins. We quantified offtake of dead (road-killed) cane toads by raptors (black kites (Milvus migrans) and whistling kites (Haliastur sphenurus)) at a site near Darwin, in the Australian wet-dry tropics. Raptors readily took dead toads, especially small ones, although native frogs were preferred to toads if available. More carcasses were removed in the dry season than the wet season, perhaps reflecting seasonal availability of alternative prey. Raptors appeared to recognize and avoid bufotoxins, and typically removed and consumed only the toads’ tongues (thereby minimizing toxin uptake). The invasion of cane toads thus constitutes a novel prey type for scavenging raptors, rather than (as is the case for many other native predators) a threat to population viability.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Invasive species are known to cause environmental and economic damage, requiring management by control agencies worldwide. These species often become well established in new environments long before their detection, resulting in a lack of knowledge regarding their history and dynamics. When new invasions are discovered, information regarding the source and pathway of the invasion, and the degree of connectivity with other populations can greatly benefit management strategies. Here we use invasive common starling (Sturnus vulgaris) populations from Australia to demonstrate that genetic techniques can provide this information to aid management, even when applied to highly vagile species over continental scales. Analysis of data from 11 microsatellites in 662 individuals sampled at 17 localities across their introduced range in Australia revealed four populations. One population consisted of all sampling sites from the expansion front in Western Australia, where control efforts are focused. Despite evidence of genetic exchange over both contemporary and historical timescales, gene flow is low between this population and all three more easterly populations. This suggests that localized control of starlings on the expansion front may be an achievable goal and the long-standing practice of targeting select proximal eastern source populations may be ineffective on its own. However, even with low levels of gene flow, successful control of starlings on the expansion front will require vigilance, and genetic monitoring of this population can provide essential information to managers. The techniques used here are broadly applicable to invasive populations worldwide.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Victorian government implemented legislation for all new houses to achieve a 6 star rating since May 2011. It is found that having a higher star rating would provide financial and environmental benefits, however the question remains- is this sufficient to satisfy the occupants living in such houses? Are the occupants actually satisfied with the amount of money they have invested in their home? This study investigates the level of satisfaction of occupants living in different star rated houses, and explores if there is a link between the star rating of the house and the satisfaction of the occupants living in such houses.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This research discerned and analysed the politics of non-Indigenous solidarity with Indigenous struggles in southeast Australia, producing a valuable resource for present and future generations of non-Indigenous activists. The research responds to Indigenous people’s challenges and attempts to draw non-Indigenous people into consideration of self-understanding, interests and complicity.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The relative value of temperate mangroves to fish, and the processes driving patterns of microhabitat use within this habitat, are unknown. There are 3 quickly identifiable microhabitats within temperate Australian mangroves: (1) forest (the area of mangroves with trees); (2) pneumatophores (the area directly seaward of the forest without trees but with pneumatophores [aerial roots]); and (3) channel (the area directly seaward of the pneumatophores without gross structural attributes such as trees or pneumatophores). Duplicate fyke and gill nets were both initially used to sample fish in the 3 microhabitats described above. Sampling took place across the seaward edge of mangroves on 10 sampling occasions (5 night and 5 day), in a large estuarine system in SE Australia. Fish assemblages (693 fish from 20 species and 15 families) varied significantly (p < 0.05) between the forest and the channel, and between diel periods for each gear (net type), but there was little difference in the assemblage structure of fish between forest–pneumatophore or pneumatophore–channel microhabitats. Juvenile lifestages (61% of all fish) and commercially important taxa (76%) were common. Abundance, biomass and species richness of fish were generally lower in the forest than the other microhabitats, but this pattern varied significantly (p < 0.05) between diel periods, among sampling occasions, and with water depth. Highly quantitative pop nets provided a preliminary assessment of whether differential gear selectivity caused patterns between microhabitats, but less rich fish assemblages were again recorded in forests than in pneumatophores. The importance of predation in structuring fish assemblages across microhabitats was assessed by measuring survival of juvenile fish tethered in 3 predation treatments (predator exclusion, cage control, and uncaged). Survival rates were high across the predator treatments and did not vary among microhabitats. The variation in fish assemblages across microhabitats within mangroves was not consistent with a model of mangrove structure providing a refuge for juvenile fish from predation, but instead could indicate differences in efficiency of gear types among microhabitats and/or other ‘edge effect’-driven processes such as the provision of food and/or shelter.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background : Using two different measures of park area, at three buffer distances, we sought to investigate the ways in which park area and proximity to parks, are related to the frequency of walking (for all purposes) in Australian adults. Little previous research has been conducted in this area, and results of existing research have been mixed.

Methods : Residents of 50 urban areas in metropolitan Melbourne, Australia completed a physical activity survey (n = 2305). Respondents reported how often they walked for >=10 minutes in the previous month. Walking frequency was dichotomised to 'less than weekly' (less than 1/week) and 'at least weekly' (1/week or more). Using Geographic Information Systems, Euclidean buffers were created around each respondent's home at three distances: 400metres (m), 800 m and 1200 m. Total area of parkland in each person's buffer was calculated for the three buffers. Additionally, total area of 'larger parks', (park space >= park with Australian Rules Football oval (17,862 m2)), was calculated for each set of buffers. Area of park was categorised into tertiles for area of all parks, and area of larger parks (the lowest tertile was used as the reference category). Multilevel logistic regression, with individuals nested within areas, was used to estimate the effect of area of parkland on walking frequency.

Results : No statistically significant associations were found between walking frequency and park area (total and large parks) within 400 m of respondent's homes. For total park area within 800 m, the odds of walking at least weekly were lower for those in the mid (OR 0.65, 95% CI 0.46-0.91) and highest (OR 0.65, 95% CI 0.44-0.95) tertile of park area compared to those living in areas with the least amount of park area. Similar results were observed for total park area in the 1200 m buffers. When only larger parks were investigated, again more frequent walking was less likely when respondents had access to a greater amount of park area.

Conclusions : In this study we found that more park area in residential environments reduced the odds of walking more frequently. Other area characteristics such as street connectivity and destinations may underlay these associations by negatively correlating with park area.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Yuendumu, located in the Tanami desert of the Northern Territory, is home to the largest Warlpiri community in Australia. We examine the role of Australian Rules football in this remote Indigenous community. Football is seen to operate on many layers of Warlpiri culture, from the traditional game of ‘purlja’, the introduction of modern football in the 1950s, the growth of sports weekends, community football and the Alice Springs competition to the journey of Liam Jurrah, the first Warlpiri man to make the journey from being a desert footballer to emerging as an Australian Football League star. The importance of football in Yuendumu is revealed as a vehicle for social cohesion, group identity, pride and joy, and as an expression of manhood, enabling its young men to see themselves as modern-day Warlpiri warriors.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

School suspension is associated with school dropout, crime, delinquency, and alcohol and other drug use for the suspended student. Important research questions are how academic and related factors are relevant to the school suspension process and the generality of the process in different sites. State-representative samples of Grade 7 students (N = 1,945) in Washington State, United States and Victoria, Australia were followed from 2002 to 2004. In both states, Grade 7 school suspension was associated with higher rates of nonviolent antisocial behavior and suspension 24 months later, before Grade 8 factors were entered into the model. Relevant factors were Grade 8 low school grades and association with antisocial peers, as well as Grade 8 antisocial behavior in Washington State only. The implications of these findings for the ways in which suspension is used in schools are outlined.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The constitution of climate change as an ‘emergency’ invites an appeal to sovereign
power that is troubling in the context of Australia’s colonial history. Climate change is
an unsettling and dispossessing force that, while unprecedented in many ways, can be situated among a series of environmental and social crises that have shaped a discourse of anxious or insecure non-Indigenous belonging in this country. This discourse seeks to render non-Indigenous Australian place as secure and absolute, and understands environmental change as a threat to this goal. This threat appeals to an emergency framing, and in turn to a reassertion, in line with the insights of Agamben, of an exclusive sovereignty that rehearses the foundational dispossessions of colonization. At the same time, climate change is initiating new ways of conceptualizing human relations with place that challenge the value of sovereign status. It enacts realities that refuse a singular emergency and instead generate community from a reorientation of places, times and more-than-human relations. Thought in this way as a creative force that is shaping communities and environments, climate change becomes a source of critical insight for the possibilities of a decolonized future.