989 resultados para 178-1098
Resumo:
Silicon carbide is one of the promising materials for the fabrication of various one- and two-dimensional nanostructures. In this chapter, we discuss experimental and theoretical studies of the plasma-enabled fabrication of silicon carbide quantum dots, nanowires, and nanorods. The discussed fabrication methods include plasma-assisted growth with and without anodic aluminium oxide membranes and with or without silane as a source of silicon. In the silane-free experiments, quartz was used as a source of silicon to synthesize the silicon carbide nanostructures in an environmentally friendly process. The mechanism of the formation of nanowires and nanorods is also discussed.
Resumo:
New ways of thinking are required in teacher education to promote beginning teachers as change agents in education. Twenty years after the Salamanca Statement (UNESCO, 1994) that called for schools to provide equitable opportunities for all children, teaching practices in many classrooms are informed by the deficit view of learning. Beginning teachers need to be prepared to challenge the ideological influences that operate in schools. Deleuze and Guattari’s (1987) model of the rhizome is used to report one beginning teacher’s journey as she learnt to negotiate structural and personal obstacles to create an inclusive learning environment. Data from reflective diaries, semi-structured interviews and classroom observations highlight contextual and personal factors in one case study that contributed to the nonlinear, complex process of becoming an inclusive educator. The paper concludes by arguing the voice of beginning teachers is essential for the ongoing movement towards the creation of just, inclusive schools.
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Quantifying the impact of biochemical compounds on collective cell spreading is an essential element of drug design, with various applications including developing treatments for chronic wounds and cancer. Scratch assays are a technically simple and inexpensive method used to study collective cell spreading; however, most previous interpretations of scratch assays are qualitative and do not provide estimates of the cell diffusivity, D, or the cell proliferation rate,l. Estimating D and l is important for investigating the efficacy of a potential treatment and provides insight into the mechanism through which the potential treatment acts. While a few methods for estimating D and l have been proposed, these previous methods lead to point estimates of D and l, and provide no insight into the uncertainty in these estimates. Here, we compare various types of information that can be extracted from images of a scratch assay, and quantify D and l using discrete computational simulations and approximate Bayesian computation. We show that it is possible to robustly recover estimates of D and l from synthetic data, as well as a new set of experimental data. For the first time, our approach also provides a method to estimate the uncertainty in our estimates of D and l. We anticipate that our approach can be generalized to deal with more realistic experimental scenarios in which we are interested in estimating D and l, as well as additional relevant parameters such as the strength of cell-to-cell adhesion or the strength of cell-to-substrate adhesion.
Resumo:
The authors confront the challenges facing OHS regulators and stakeholders in a new and different world dominated by service industries and globalisation rather than manufacturing industries and protection. They explore new models of OHS regulation that take account of gaps and deficiencies in the current arrangements.
Resumo:
Mobile robots and animals alike must effectively navigate their environments in order to achieve their goals. For animals goal-directed navigation facilitates finding food, seeking shelter or migration; similarly robots perform goal-directed navigation to find a charging station, get out of the rain or guide a person to a destination. This similarity in tasks extends to the environment as well; increasingly, mobile robots are operating in the same underwater, ground and aerial environments that animals do. Yet despite these similarities, goal-directed navigation research in robotics and biology has proceeded largely in parallel, linked only by a small amount of interdisciplinary research spanning both areas. Most state-of-the-art robotic navigation systems employ a range of sensors, world representations and navigation algorithms that seem far removed from what we know of how animals navigate; their navigation systems are shaped by key principles of navigation in ‘real-world’ environments including dealing with uncertainty in sensing, landmark observation and world modelling. By contrast, biomimetic animal navigation models produce plausible animal navigation behaviour in a range of laboratory experimental navigation paradigms, typically without addressing many of these robotic navigation principles. In this paper, we attempt to link robotics and biology by reviewing the current state of the art in conventional and biomimetic goal-directed navigation models, focusing on the key principles of goal-oriented robotic navigation and the extent to which these principles have been adapted by biomimetic navigation models and why.
Resumo:
There is a general perception that public confidence in the insolvency profession is low as the result of the recent unethical practices of a few high profile liquidators. As a result, the effectiveness of the current regulatory mechanisms has been questioned, leading to a review of the performance of insolvency practitioners and subsequent regulation proposals. The challenge for the insolvency profession is balancing the expectations of the general public whilst ensuring that the obligations and duties imposed upon them are performed to acceptable and realistic standards. It is difficult (if not impossible) for the profession to meet this challenge in the absence of a cohesive framework which identifies those issues that require further regulation as opposed to those that relate to general education on the insolvency process. This paper will examine the audit expectations gap theory in the context of insolvency practitioners and suggests that a model based on this theory provides an effective framework for evaluating the regulation of the insolvency industry.
Resumo:
Treatment performance of bioretention basins closely depends on hydrologic and hydraulic factors such as rainfall characteristics and inflow and outflow discharges. An in-depth understanding of the influence of these factors on water quality treatment performance can provide important guidance for effective bioretention basin design. In this paper, hydraulic and hydrologic factors impacting pollutant removal by a bioretention basin were assessed under field conditions. Outcomes of the study confirmed that the antecedent dry period plays an important role in influencing treatment performance. A relatively long antecedent dry period reduces nitrite and ammonium concentrations while increasing the nitrate concentration, which confirms that nitrification occurs within the bioretention basin. Additionally, pollutant leaching influences bioretention basin treatment performance, reducing the nutrients removal efficiency, which was lower for high rainfall events. These outcomes will contribute to a greater understanding of the treatment performance of bioretention basins, assisting in the design, operation and maintenance of these systems.
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Bats have been shown to use information from the Earth's magnetic field during orientation. However, the mechanism underlying this ability remains unknown. In this study we investigated whether bats possess a polarity- or inclination-based compass that could be used in orientation. We monitored the hanging position of adult Nyctalus plancyi in the laboratory in the presence of an induced magnetic field of twice Earth-strength. When under the influence of a normally aligned induced field the bats showed a significant preference for hanging at the northern end of their roosting basket. When the vertical component of the field was reversed, the bats remained at the northern end of the basket. However, when the horizontal component of the field was reversed, the bats changed their positions and hung at the southern end of the basket. Based on these results, we conclude that N. plancyi, unlike all other non-mammalian vertebrates tested to date, uses a polarity-based compass during orientation in the roost, and that the same compass is also likely to underlie bats' long-distance navigation abilities.
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Si has attracted enormous research and manufacturing attention as an anode material for lithium ion batteries (LIBs) because of its high specific capacity. The lack of a low cost and effective mechanism to prevent the pulverization of Si electrodes during the lithiation/ delithiation process has been a major barrier in the mass production of Si anodes. Naturally abundant gum arabic (GA), composed of polysaccharides and glycoproteins, is applied as a dualfunction binder to address this dilemma. Firstly, the hydroxyl groups of the polysaccharide in GA are crucial in ensuring strong binding to Si. Secondly, similar to the function of fiber in fiberreinforced concrete (FRC), the long chain glycoproteins provide further mechanical tolerance to dramatic volume expansion by Si nanoparticles. The resultant Si anodes present an outstanding capacity of ca. 2000 mAh/g at a 1 C rate and 1000 mAh/g at 2 C rate, respectively, throughout 500 cycles. Excellent long-term stability is demonstrated by the maintenance of 1000 mAh/g specific capacity at 1 C rate for over 1000 cycles. This low cost, naturally abundant and environmentally benign polymer is a promising binder for LIBs in the future.
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This paper provides an outline of the work undertaken by nurses who participated in the relief effort as members of Australian medical teams during the Sumatra-Andaman earthquake and tsunami response. This profile is contrasted with the information provided by nurses who registered their interest in volunteering to help via the Australian Tsunami Hotline. The paper provides an overview of the skills and background of the nurses who provided information to the hotline and describes the range and extent of experience among this cohort of potential volunteers. This data is compared to nursing workforce data and internal rates of volunteering in Australia. The paper concludes that further research is necessary to examine the motivations of and disincentives for nurses to volunteer for overseas (disaster) work and, to develop an improved understanding within the discipline of the skills and experience required of volunteer responders. Further, it is argued that the development of standards for the collection of disaster health volunteer data would assist future responses and provide better tools for developing an improved understanding of disaster volunteering.
Resumo:
Synopsis and review of the Australian feature film Balibo, directed by Robert Connolly.