999 resultados para Crossection of stipe and rhizome


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Aims: This study determined whether the visibility benefits of positioning retroreflective strips in biological motion configurations were evident at real world road worker sites. Methods: 20 visually normal drivers (M=40.3 years) participated in this study that was conducted at two road work sites (one suburban and one freeway) on two separate nights. At each site, four road workers walked in place wearing one of four different clothing options: a) standard road worker night vest, b) standard night vest plus retroreflective strips on thighs, c) standard night vest plus retroreflective strips on ankles and knees, d) standard night vest plus retroreflective strips on eight moveable joints (full biomotion). Participants seated in stationary vehicles at three different distances (80m, 160m, 240m) rated the relative conspicuity of the four road workers using a series of a standardized visibility and ranking scales. Results: Adding retroreflective strips in the full biomotion configuration to the standard night vest significantly (p<0.001) enhanced perceptions of road worker visibility compared to the standard vest alone, or in combination with thigh retroreflective markings. These visibility benefits were evident at all distances and at both sites. Retroreflective markings at the ankles and knees also provided visibility benefits compared to the standard vest, however, the full biomotion configuration was significantly better than all of the other configurations. Conclusions: These data provide the first evidence that the benefits of biomotion retroreflective markings that have been previously demonstrated under laboratory and closed- and open-road conditions are also evident at real work sites.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper summarises some of the recent studies on various types of learning approaches that have utilised some form of Web 2.0 services in curriculum design to enhance learning. A generic implementation model of this integration will then be presented to illustrate the overall learning implementation process. Recently, the integration of Web 2.0 technologies into learning curriculum has begun to get a wide acceptance among teaching instructors across various higher learning institutions. This is evidenced by numerous studies which indicate the implementation of a range of Web 2.0 technologies into their learning design to improve learning delivery. Moreover, recent studies also have shown that the ability of current students to embrace Web 2.0 technologies is better than students using existing learning technology. Despite various attempts made by teachers in relation to the integration, researchers have noted a lack of integration standard to help in curriculum design. The absence of this standard will restrict the capacity of Web 2.0 adaptation into learning and adding more the complexity to provide meaningful learning. Therefore, this paper will attempt to draw a conceptual integration model which is being generated to reflect how learning activities with some facilitation of Web 2.0 is currently being implemented. The design of this model is based on shared experiences by many scholars as well as feedback gathered from two separate surveys conducted on teachers and a group of 180 students. Furthermore, this paper also recognizes some key components that generally engage in the design of a Web 2.0 teaching and learning which need to be addressed accordingly. Overall, the content of this paper will be organised as follows. The first part of the paper will introduce the importance of Web 2.0 implementation in teaching and learning from the perspective of higher education institutions and those challenges surrounding this area. The second part summarizes related works done in this field and brings forward the concept of designing learning with the incorporation of Web 2.0 technology. The next part presents the results of analysis derived from the two student and teachers surveys on using Web 2.0 during learning activities. This paper concludes by presenting a model that reflects several key entities that may be involved during the learning design.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Increasing resistance of rabbits to myxomatosis in Australia has led to the exploration of Rabbit Haemorrhagic Disease, also called Rabbit Calicivirus Disease (RCD) as a possible control agent. While the initial spread of RCD in Australia resulted in widespread rabbit mortality in affected areas, the possible population dynamic effects of RCD and myxomatosis operating within the same system have not been properly explored. Here we present early mathematical modelling examining the interaction between the two diseases. In this study we use a deterministic compartment model, based on the classical SIR model in infectious disease modelling. We consider, here, only a single strain of myxomatosis and RCD and neglect latent periods. We also include logistic population growth, with the inclusion of seasonal birth rates. We assume there is no cross-immunity due to either disease. The mathematical model allows for the possibility of both diseases to be simultaneously present in an individual, although results are also presented for the case where co infection is not possible, since co-infection is thought to be rare and questions exist as to whether it can occur. The simulation results of this investigation show that it is a crucial issue and should be part of future field studies. A single simultaneous outbreak of RCD and myxomatosis was simulated, while ignoring natural births and deaths, appropriate for a short timescale of 20 days. Simultaneous outbreaks may be more common in Queensland. For the case where co-infection is not possible we find that the simultaneous presence of myxomatosis in the population suppresses the prevalence of RCD, compared to an outbreak of RCD with no outbreak of myxomatosis, and thus leads to a less effective control of the population. The reason for this is that infection with myxomatosis removes potentially susceptible rabbits from the possibility of infection with RCD (like a vaccination effect). We found that the reduction in the maximum prevalence of RCD was approximately 30% for an initial prevalence of 20% of myxomatosis, for the case where there was no simultaneous outbreak of myxomatosis, but the peak prevalence was only 15% when there was a simultaneous outbreak of myxomatosis. However, this maximum reduction will depend on other parameter values chosen. When co-infection is allowed then this suppression effect does occur but to a lesser degree. This is because the rabbits infected with both diseases reduces the prevalence of myxomatosis. We also simulated multiple outbreaks over a longer timescale of 10 years, including natural population growth rates, with seasonal birth rates and density dependent(logistic) death rates. This shows how both diseases interact with each other and with population growth. Here we obtain sustained outbreaks occurring approximately every two years for the case of a simultaneous outbreak of both diseases but without simultaneous co-infection, with the prevalence varying from 0.1 to 0.5. Without myxomatosis present then the simulation predicts RCD dies out quickly without further introduction from elsewhere. With the possibility of simultaneous co-infection of rabbits, sustained outbreaks are possible but then the outbreaks are less severe and more frequent (approximately yearly). While further model development is needed, our work to date suggests that: 1) the diseases are likely to interact via their impacts on rabbit abundance levels, and 2) introduction of RCD can suppress myxomatosis prevalence. We recommend that further modelling in conjunction with field studies be carried out to further investigate how these two diseases interact in the population.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background The increasing popularity and use of the internet makes it an attractive option for providing health information and treatment, including alcohol/other drug use. There is limited research examining how people identify and access information about alcohol or other drug (AOD) use online, or how they assess the usefulness of the information presented. This study examined the strategies that individuals used to identify and navigate a range of AOD websites, along with the attitudes concerning presentation and content. Methods Members of the general community in Brisbane and Roma (Queensland, Australia) were invited to participate in a 30-minute search of the internet for sites related to AOD use, followed by a focus group discussion. Fifty one subjects participated in the study across nine focus groups. Results Participants spent a maximum of 6.5 minutes on any one website, and less if the user was under 25 years of age. Time spent was as little as 2 minutes if the website was not the first accessed. Participants recommended that AOD-related websites should have an engaging home or index page, which quickly and accurately portrayed the site’s objectives, and provided clear site navigation options. Website content should clearly match the title and description of the site that is used by internet search engines. Participants supported the development of a portal for AOD websites, suggesting that it would greatly facilitate access and navigation. Treatment programs delivered online were initially viewed with caution. This appeared to be due to limited understanding of what constituted online treatment, including its potential efficacy. Conclusions A range of recommendations arise from this study regarding the design and development of websites, particularly those related to AOD use. These include prudent use of text and information on any one webpage, the use of graphics and colours, and clear, uncluttered navigation options. Implications for future website development are discussed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study examines nascent entrepreneurship by comparing individuals engaged in nascent activities (n=380) with a control group (n=608), after screening a sample from the general population (n=30,427). The study then follows the developmental process of nascent entrepreneurs for 18 months. Bridging and bonding social capital, consisting of both strong and weak ties, was a robust predictor for nascent entrepreneurs, as well as for advancing through the start-up process. With regard to outcomes like first sale or showing a profit, only one aspect of social capital, viz. being a member of a business network, had a statistically significant positive effect. The study supports human capital in predicting entry into nascent entrepreneurship, but only weakly for carrying the start-up process towards successful completion.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The current paper compares and investigates the discrepancies in motivational drives of project team members with respect to their project environment in collocated and distributed (virtual) project teams. The set of factors, which in this context are called ‘Sense of Ownership’, is used as a scale to measure these discrepancies using one tailed t tests. These factors are abstracted from theories of motivation, team performance, and team effectiveness and are related to ‘Nature of Work’, ‘Rewards’, and ‘Communication’. It has been observed that ‘virtual ness’ does not seem to impact the motivational drives of the project team members or the way the project environments provide or support those motivational drives in collocated and distributed projects. At a more specific level in terms of the motivational drives of the project team (‘WANT’) and the ability of the project environment to provide or support those factors (‘GET’), in collocated project teams, significant discrepancies were observed with respect to financial and non financial rewards, learning opportunities, nature of work and project specific communication, while in distributed teams, significant discrepancies with respect to project centric communication, followed by financial rewards and nature of work. Further, distributed project environments seem to better support the team member motivation than collocated project environments. The study concludes that both the collocated and distributed project environments may not be adequately supporting the motivational drives of its project team members, which may be frustrating to them. However, members working in virtual team environments may be less frustrated than their collocated counterparts as virtual project environments are better aligned with the motivational drives of their team members vis-à-vis the collocated project environments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The current paper compares and investigates the discrepancies in motivational drives of project team members with respect to their project environment in collocated and distributed (virtual) project teams. The set of factors, which in this context are called ‘Sense of Ownership’, is used as a scale to measure these discrepancies using one tailed t tests. These factors are abstracted from theories of motivation, team performance, and team effectiveness and are related to ‘Nature of Work’, ‘Rewards’, and ‘Communication’. It has been observed that ‘virtualness’ does not seem to impact the motivational drives of the project team members or the way the project environments provide or support those motivational drives in collocated and distributed projects. At a more specific level in terms of the motivational drives of the project team (‘WANT’) and the ability of the project environment to provide or support those factors (‘GET’), in collocated project teams, significant discrepancies were observed with respect to financial and non financial rewards, learning opportunities, nature of work and project specific communication, while in distributed teams, significant discrepancies with respect to project centric communication, followed by financial rewards and nature of work. Further, distributed project environments seem to better support the team member motivation than collocated project environments. The study concludes that both the collocated and distributed project environments may not be adequately supporting the motivational drives of its project team members, which may be frustrating to them. However, members working in virtual team environments may be less frustrated than their collocated counterparts as virtual project environments are better aligned with the motivational drives of their team members vis-à-vis the collocated project environments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The purpose of this paper is to present a theoretical framework to investigate the relationship between work motivation, organizational commitment, and professional commitment in temporary organizations. Through a review of theory, we contend that work motivation has two major patterns- internal motivation (that includes intrinsic, need-based, and self-deterministic theories), and external motivation (that includes cognitive or process-based theories of motivation) through which it has been investigated. We also subsume the nature of employee commitment to be of three types- affective, continuance, and normative. This commitment may either be towards organization or profession. A literature review reveals that the characteristics of the temporary organization - specifically tenure, and task - regulate the relationship between work motivation, and organizational commitment, and professional commitment. Relevant propositions are presented.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The ultimate goal of periodontal tissue engineering is to produce predictable regeneration of alveolar bone, root cementum, and periodontal ligament, which are lost as a result of periodontal diseases. To achieve this goal, it is of great importance to develop novel bioactive materials which could stimulate the proliferation, differentiation and osteogenic/cementogenic gene expression of periodontal ligament cells (PDLCs) for periodontal regeneration. In this study, we synthesized novel Ca7Si2P2O16 ceramic powders for the first time by the sol–gel method and investigated the biological performance of PDLCs after exposure to different concentrations of Ca7Si2P2O16 extracts. The original extracts were prepared at 200 mg ml-1 and further diluted with serum-free cell culture medium to obtain a series of diluted extracts (100, 50, 25, 12.5 and 6.25 mg ml–1). Proliferation, alkaline phosphatase(ALP) activity, Ca deposition, and osteogenesis/cementogenesis-related gene expression (ALP, Col I, Runx2 and CEMP1) were assayed for PDLCs on days 7 and 14. The results showed that the ionic products from Ca7Si2P2O16 powders significantly stimulated the proliferation, ALP activity, Ca deposition and osteogenesis/cementogenesisrelated gene expression of PDLCs. In addition, it was found that Ca7Si2P2O16 powders had excellent apatite-mineralization ability in simulated body fluids. This study demonstrated that Ca7Si2P2O16 powders with such a specific composition possess the ability to stimulate the PDLC proliferation and osteoblast/cemenoblast-like cell differentiation, indicating that they are a promising bioactive material for periodontal tissue regeneration application.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Individual science teachers who have inspired colleagues to transform their classroom praxis have been labelled transformational leaders. As the notion of distributed leadership became more accepted in the educational literature, the focus on the individual teacher-leader shifted to the study of leadership praxis both by individuals (whoever they might be) and by collectives within schools and science classrooms. This review traces the trajectory of leadership research, in the context of learning and teaching science, from an individual focus to a dialectical relationship between individual and collective praxis. The implications of applying an individual-collective perspective to praxis for teachers, students and their designated leaders are discussed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Positive and negative small ions, aerosol ion and number concentration and dc electric fields were monitored at an overhead high-voltage power line site. We show that the emission of corona ions was not spatially uniform along the lines and occurred from discrete components such as a particular set of spacers. Maximum ion concentrations and atmospheric dc electric fields were observed at a point 20 m downwind of the lines. It was estimated that less than 7% of the total number of aerosol particles was charged. The electrical parameters decreased steadily with further downwind distance but remained significantly higher than background.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This brief paper will introduce a new theoretical framework or model which may be useful for putting a structure around the theme of ageing and its accompanying grief and loss. It is especially appropriate in the context of counselling families living with dementia, including those individuals with a diagnosis of alzheimers disease. The paper describes the origin of the Spanish expressions of the `wall of tears’ and `house of tears’ and involves an historical narrative of the first author as context to the framework.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This article explores the influence of new modes of governance on the production of criminological knowledge. In doing so, it examines the rise of discourses on risk and critiques the ways in which academic environments are changing under new managerialist philosophies. The article further explores the increasing 'commodification of criminological knowledge' and analyses its effect on contemporary criminological scholarship. Finally, this article examines the contours of critical criminological scholarship and advocates for a criminology of resistance.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Australian Federal Commissioner of Taxation recently released Draft Taxation Ruling TR 2008/D3 with the stated purpose of clarifying ‘what profits derived from the leasing of ships or aircraft fall within the ship and aircraft articles of each of Australia’s tax treaties’. In particular, TR 2008/D3 explains the taxing rights over different types of leasing profits, such as a full basis lease in respect of any transport by a ship operated in international traffic and bareboat leases which are ancillary to the lessor transport operations of ships in international traffic. This article outlines the Commissioner’s views on the application of the standard ships and aircraft articles in the tax treaties to which it is a party as well as considering the major variations on the standard adoption. In doing so, guidance is provided as to the allocation of taxing rights of ship and aircraft leasing profits under Australia’s tax treaties.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Each year the Australian Federal Treasury releases its Tax Expenditures Statement providing details of concessions, benefits, and incentives delivered through the tax regime to Australian taxpayers. The current Tax Expenditures Statement, released on 25 January 2008, lists approximately 300 tax expenditures and reports on the estimated pecuniary value in terms of revenue foregone, estimated to be a total of $50.12 billion for the 2006-07 financial year. Apart from the annual Tax Expenditures Statement, and despite the recurring fiscal impact, there is very little other scrutiny of Australia’s Federal tax expenditures program. This is despite tax expenditures often being seen as an alternative to direct expenditures with similar impact on the Federal budget. The object of tax expenditures is to provide government assistance and meet government objectives, and, as such, tax expenditures are departures from the revenue raising aspect of the tax regime. Within this context, this article examines the fundamental concept of tax expenditures as contrasted with direct expenditures and considers the role they play in the current tax regime.