6 resultados para Navegação - séc.16-17

em Deakin Research Online - Australia


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This study investigated community-based monitoring in Victoria’s Marine National Parks (MNPs) and Sanctuaries (MSs) from January to May 2004. The primary aim of this study was to evaluate the potential for community-based monitoring projects to assist in the collection of data for the management of Victoria’s MNPs and MSs. The pilot habitats that were assessed included subtidal reefs at the Merri MS, intertidal reefs at Ricketts Point MS and seagrass beds at Corner Inlet MNP. The three main objectives for this study were to:
 - Develop a template for the monitoring of marine habitats by community groups.
 - Assess the quality and integrity of data collected by community volunteers.
 - Determine a sustainable model for community monitoring of marine habitats.
Three standard operating procedures (SOPs) in the form of a “how to” manual, were developed for each habitat type. The SOPs were adapted from scientifically robust studies and developed in consultation with community volunteer groups by means of field trials. Volunteer feedback assisted in the final SOP design. The SOP will allow Parks Victoria Rangers to develop community-based programs within the parks. The SOPs are accessible as Parks Victoria Technical Series Numbers 16, 17 and 18. Data collected by volunteers across the three habitat sites were assessed and compared to that collected by scientists. It was found that data quality collected by volunteers was dependent on habitat type and the type of measurement the volunteer was required to assess. Volunteer estimation measurements were highly variable across all three habitat sites, compared to quantitative data collection. Subtidal monitoring had the greatest potential for inconsistency in data collection. Intertidal monitoring is the most sustainable of the three habitat monitoring procedures. Sustainability of community-based monitoring programs is dependent on continued support and training by the management authority of Victoria’s MNPs and MSs. For the expansion of the monitoring programs to other MNPs and MSs, the management authority could expand strong relationships with the community volunteer groups.

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Prehension is a fundamental skill usually performed as part of a complex action sequence in everyday tasks. Using an information processing framework, these studies examined the effects of task complexity, defined by the number of component movement elements (MEs), on performance of prehension tasks. Of interest was how motor control and organisation might be influenced by age and/or motor competence. Three studies and two longitudinal case studies examined kinematic characteristics of prehension tasks involving one-, two- and three-MEs: reach and grasp (low-complexity); reach, grasp and object placement (moderate-complexity); and reach, grasp and double placement of object (high-complexity). A pilot study established the suitability of tasks and procedures for children aged 5-, 8- and 11-years and showed that responses to task complexity and object size manipulations were sensitive to developmental changes, with increasing age associated with faster movements. Study 2 explored complexity and age effects further for children aged 6- and 11-years and adults. Increasing age was associated with shorter and less variable movement times (MTs) and proportional deceleration phases (%DTs) across all MEs. Task complexity had no effect on simple reaction time (SRT), suggesting that there may be little preprogramming of movements beyond the first ME. In addition, MT was longer and more on-line corrections were evident for the high- compared to the moderate-complexity task for ME1. Task complexity had a greater influence on movements in ME2 and ME3 than ME1. Adults, but not children, showed task specific adaptations in ME2. Study 3 examined performance of children with different levels of motor competence aged between 5- and 10-years. Increasing age was associated with shorter SRTs, and MTs for ME1 only. A decrease in motor competence was associated with greater difficulty in planning and controlling movements as indicated by longer SRTs, higher %DTs and more on-line corrections, especially in ME2. Task complexity affected movements in all MEs, with a greater influence on ME1 compared to Study 2. Findings also indicated that performance in MEs following prehension may be especially sensitive to motor competence effects on movement characteristics. Case studies for two children at risk of Developmental Coordination Disorder (DCD) revealed two different patterns of performance change over a 16-17 month period, highlighting the heterogeneous nature of DCD. Overall, findings highlighted age-related differences, and the role of motor competence, in the ability to adapt movements to task specific requirements. Results are useful in guiding movement education programmes for children with both age-appropriate and lower levels of motor competence.

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Ant-like agents forage between two points. These agents' probabilistic movements are based on the use of two pheromones; one marking trails towards the goal and another marking trails back to the starting point. Path selection decisions are influenced by the relative levels of attractive and repulsive pheromone in each agent's local environment. Our work in [5] evaluates three pheromone perception strategies, investigating path formation speed, quality, directionality, robustness and adaptability under different parameter settings(degree of randomness, pheromone evaporation rate and pheromone diffusion rate). We re-evaluate two of these strategies in terms of the amount of information they provide using Shannon's formulation [3, 4, 8, 9, 12, 14, 15, 16, 17]. We determine information as the difference between uncertainty before and after path selection decisions. Our focus in this paper is on investigating relationships between the emergence of the shortest path and the amount of stigmergic information that exists in the form of pheromone. Agents are deployed centrally and emergence measures are determined using the worst, reference and best cases observed in [5]. Additionally, the amount of local and global information that is available to agents in each movement step is evaluated. Furthermore, Pearson's correlation coefficients between measures of emergence and the amount of information are calculated. The significance of these correlation coefficients is tested using a 2 tailed test at 1% level of significance. Consequently the relationship between the amount of information and emergent behaviour is established. Significant relationships between information and the emergence of the shortest path exist when strong emergent behaviour is present.

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The current study documents the changing rates of cannabis use, misuse and cannabis-related social harms among Australian adolescents as they grow into young adulthood. It utilised data from a longitudinal study of young people at ages 15, 16, 17, and 19. The rates of cannabis use were found to increase as participants aged; past year use increased from 7.5% at age 15 to 29.8% at age 19. Further, at ages 17 and 19, cannabis use was more prevalent among males than females. Among those who reported cannabis use, the rates of cannabis-related harms were low to moderate, and did not increase with age in the same manner as rates of cannabis use. The most prevalent self-reported cannabis-related harm was anxiety/depression; affecting between 20–30% of the cannabis users at each age. These findings may assist in understanding the extent of cannabis-related problems among youth, and in planning relevant services.

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A failure of a cell to self destruct has long been associated with cancer progression and development. The fact that tumour cells may not instigate cell arrest or activate cell death mechanisms upon cancer drug delivery is a major concern. Autophagy is a mechanism whereby cell material can be engulfed and digested while apoptosis is a self-killing mechanism, both capable of hindering multiplication after cell injury. In particular situations, autophagy and apoptosis seem to co-exist simultaneously or interdependently with the aid of mutual proteins. This review covers roles of microRNAs and chemopreventive agents and makes an attempt at outlining possible partnerships in maximizing cancer cell death with minimal normal cell damage.