132 resultados para 179
Resumo:
In spite of the extensive usage of continuous welded rails, a number of rail joints still exist in the track. Although a number of them exist as part of turnouts in the yards where the speed is not of concern, the Insultated Rail Joints (IRJs) that exist in ballasted tracks remain a source of significant impact loading. A portion of the dynamic load generated at the rail joints due to wheel passage is transmitted to the support system which leads to permanent settlements of the ballast layer with subsequent vertical misalignment of the sleepers around the rail joints. The vertical misalignment of the adjacent sleepers forms a source of high frequency dynamic load raisers causing significant maintenance work including localised grinding of railhead around the joint, re-alignment of the sleepers and/or ballast tamping or track component renewals/repairs. These localised maintenance activities often require manual inspections and disruptions to the train traffic loading to significant costs to the rail industry. Whilst a number of studies have modelled the effect of joints as dips, none have specifically attended to the effect of vertical misalignment of the sleepers on the dynamic response of rail joints. This paper presents a coupled finite element track model and rigid body track-vehicle interaction model through which the effects of vertical of sleepers on the increase in dynamic loads around the IRJ are studied. The finite element track model is employed to determine the generated dip from elastic deformations as well as the vertical displacement of sleepers around the joint. These data (dip and vertical misalignments) are then imported into the rigid body vehicle-track interaction model to calculate the dynamic loads.
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Sustainability is a global issue that urgently needs addressing, and for which the most serious consequences are for children and future generations. This insightful research text tackles one of the most significant contemporary issues of our times – the nexus between society and environment – and how early childhood education can contribute to sustainable living. By offering international and multidisciplinary research perspectives on Early Childhood Education for Sustainability, each chapter explores and investigates the complex topic of sustainability and its relationship to early childhood education. A particular emphasis that runs through this text is young children as empowered citizens, capable of both contributing to and creating change for sustainability. The chapter authors work from, or are aligned with, a transformative education paradigm that suggests the socio-constructivist frameworks currently underpinning Early Childhood Education require reframing in light of the social transformations necessary to address humanity’s unsustainable, unjust and unhealthy living patterns. This research text is designed to be provocative and challenging; in so doing it seeks to encourage exploration of current understandings about Early Childhood Education for Sustainability, offers new dimensions for more deeply informed practice, and proposes avenues for further research in this field.
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This volume stems from the 1st International Conference on Epithelial-Mesenchymal Transitions (EMT), which was convened by the editors on October 5–8, 2003 in the beautiful setting of Port Douglas, Queensland, Australia. EMT, the name given to the transformation of cells arranged in a coherent layer – epithelial cells – to more individualistic and potential motile cells – mesenchymal cells – was recognized decades ago by Prof. Elisabeth (Betty) Hay (Harvard Medical School, Boston, Mass., USA) as a primary mechanism in embryogenesis for remodelling tissues. More recently EMT has been seen as crucial to the spread and invasion of carcinoma, and more recently still, EMT-like changes have been detected in various pathologies marked by fi brosis. Despite the basic and clinical importance of EMT, this extremely rapidly growing fi eld had never previously had a conference devoted to it, and indeed the disciplines of developmental biology, cancer and pathology rarely interact although they have much to share. The chapters assembled for this volume encompass these three major themes of the meeting, development, pathology and cancer, and further highlight the commonality in terms of mechanisms and outcomes among them...
Resumo:
Objective To assess the impact of relaxed asthma recruitment standards adopted by the Australian Defence Force (ADF) in 2007. Methods A retrospective audit was conducted on clinical and administrative data for recruits, with and without mild asthma, in their first year of service. Results There was no evidence that mild asthmatics experienced worse outcomes than nonasthmatic recruits. Mild asthmatics had fewer illnesses and restricted duty days and were less costly compared to other recruits. There was no difference in the rate of discharge (attrition) between those with and without mild asthma. Conclusions The revised recruitment standards for asthma in the ADF have not resulted in unanticipated medical or administrative costs to the organisation. Health and administrative outcomes differed little between mild asthmatics and non-asthmatic recruits in their first twelve months of service.
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This paper examines a buffer scheme to mitigate the negative impacts of power-conditioned loads on network voltage and transient stabilities. The scheme is based on the use of battery energy-storage systems in the buffers. The storage systems ensure that protected loads downstream of the buffers can ride through upstream voltage sags and swells. Also, by controlling the buffers to operate in either constant impedance or constant power modes, power is absorbed or injected by the storage systems. The scheme thereby regulates the rotor-angle deviations of generators and enhances network transient stability. A computational method is described in which the capacity of the storage systems is determined to achieve simultaneously the above dual objectives of load ride-through and stability enhancement. The efficacy of the resulting scheme is demonstrated through numerical examples.
Resumo:
Purpose The purpose of this paper is to investigate the reality of financial and management accounting in a small group of small firms. Specifically, from the owner's perspective, an exploration is undertaken to see what financial information is collected, how it is used (or not) to make business decisions and evaluate the firm's performance, and the role played by the accountant in that process. Design/methodology/approach A phenomenological paradigm underpins this exploratory study. Semi‐structured interviews were undertaken with the owners of ten small firms, where the focus was on understanding what happens in an organisational setting, as opposed to theory and textbook practice. Findings The qualitative data supported prior research in other countries. The in‐depth analysis revealed a very basic understanding of accounting information and problems with the financial literacy amongst these small firm owners. Accounting reports were not widely produced or used, so an informal assessment, such as how much cash was in the bank, was the primary means of assessing business performance. Accountants were used for taxation services, although some owners sought more general business advice. Originality/value An understanding is developed of why there might be a gap between textbook rhetoric and reality of accounting practice in small firms. The conclusion is that accounting textbooks need to include more information about the reality of financial management in small firms.
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Nucleopolyhedrovirus (NPV) has become an integral part of integrated pest management (IPM) in many Australian agricultural and horticultural crops. This is the culmination of years of work conducted by researchers at the Queensland Department of Primary Industries and Fisheries (QDPI&F) and Ag Biotech Australia Pty Ltd. In the early 1970’s researchers at QDPI&F identified and isolated a virus in Helicoverpa armigera populations in the field. This NPV was extensively studied and shown to be highly specific to Helicoverpa and Heliothis species. Further work showed that when used appropriately the virus could be used effectively to manage these insects in crops such as sorghum, cotton, chickpea and sweet corn. A similar virus was first commercially produced in the USA in the 1970’s. This product, Elcar®, was introduced into Australia in the late 1970’s by Shell Chemicals with limited success. A major factor contributing to the poor adoption of Elcar was the concurrent enormous success of the synthetic pyrethroids. The importance of integrated pest management was probably also not widely accepted at that time. Gradual development of insect resistance to synthetic pyrethroids and other synthetic insecticides in Australia and the increased awareness of the importance of IPM meant that researchers once again turned their attentions to environmentally friendly pest management tools such NPV and beneficial insects. In the 1990’s a company called Rhone-Poulenc registered an NPV for use in Australian sorghum, chickpea and cotton. This product, Gemstar®, was imported from the USA. In 2000 Ag Biotech Australia established an in-vivo production facility in Australia to produce commercial volumes of a product similar to the imported product. This product was branded, ViVUS®, and was first registered and sold commercially in Australia in 2003. The initial production of ViVUS used a virus identical to the American product but replicating it in an Australian Helicoverpa species, H. armigera. Subsequent research collaboration between QDPI&F and Ag Biotech reinvigorated interest in the local virus strain. This was purified and the production system adapted to produce it on a commercial scale. This new version of ViVUS, which was branded ViVUS Gold®, was first registered and sold commercially in 2004. Widespread insect resistance to insecticides and a greater understanding of integrated pest management is leading to increased adoption of technologies such NPV in Australian agriculture.
Resumo:
Introduction: Many studies have indicated the poor psychological health of medical and dental students. However, few studies have assessed the longitudinal trajectory of that psychological health at different times in an academic year. Aim: To evaluate the positive and negative aspects of psychological health among preclinical medical and dental students in Saudi Arabia prospectively. Methods: A total of 317 preclinical medical and dental students were recruited for a longitudinal study design from second and third-year students at Umm Al-Qura University in the 2012-2013 academic year. The students were assessed at the middle of the first term and followed up after 3-monthes at the beginning of the second term. Questionnaires included assessment of depression, anxiety, stress, self-efficacy, and satisfaction with life. Results: Depression, anxiety, stress, and satisfaction with life were improved significantly at the beginning of the second term, whereas self-efficacy did not change significantly. The medical, female, and third-year student subgroups had the most significant changes. Depression and stress were significantly changed at the beginning of the second term in most demographic subgroups. Conclusion: Preclinical medical and dental students have different psychological health levels at different times of the same academic year. It is recommended to consider time of data collection when analyzing the results of such studies.
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A disintegrin and metalloprotease with thrombospondin motifs protein 1 (ADAMTS1) is a protease commonly up-regulated in metastatic carcinoma. Its overexpression in cancer cells promotes experimental metastasis, but whether ADAMTS1 is essential for metastatic progression is unknown. To address this question, we investigated mammary cancer progression and spontaneous metastasis in the MMTV-PyMT mouse mammary tumor model in Adamts1 knockout mice. Adamts1−/−/PyMT mice displayed significantly reduced mammary tumor and lung metastatic tumor burden and increased survival, compared with their wild-type and heterozygous littermates. Histological examination revealed an increased proportion of tumors with ductal carcinoma in situ and a lower proportion of high-grade invasive tumors in Adamts1−/−/PyMT mice, compared with Adamts1+/+/PyMT mice. Increased apoptosis with unaltered proliferation and vascular density in the Adamts1−/−/PyMT tumors suggested that reduced cell survival accounts for the lower tumor burden in ADAMTS1-deficient mice. Furthermore, Adamts1−/− tumor stroma had significantly lesser amounts of proteolytically cleaved versican and increased numbers of CD45+ leukocytes. Characterization of immune cell gene expression indicated that cytotoxic cell activation was increased in Adamts1−/− tumors, compared with Adamts1+/+ tumors. This finding is supported by significantly elevated IL-12+ cell numbers in Adamts1−/− tumors. Thus, in vivo ADAMTS1 may promote mammary tumor growth and progression to metastasis in the PyMT model and is a potential therapeutic target to prevent metastatic breast cancer.
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Australian charities have a new regulator in the form of the Australian Charities and Not-for-profits Commission (ACNC) which began operations in December 2012; and new governance rules which applied from 1 July 2013. While there is some uncertainty over the ACNC's future, the new legislative framework currently applies to approximately 58,000 charities which seek federal tax concessions and other benefits, and includes governance standards that apply across charitable organisational forms (company, trust and association) with some exceptions. The governance standards are a minimum benchmark that many charities will already meet, if they are companies or incorporated associations.
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This chapter focuses on the more strategic activities that lead people in the regional community to decide how they want to respond to climate change. Such strategic activities include analysing, prioritising and deciding upon the best course of action. Planning for climate adaptation (usually seen to include the setting of visions and objectives, the determination of key strategies and the monitoring of broad outcomes) encompasses the strategic activities involved in the system of governance for climate adaptation. Planning occurs at all scales from global to the business, property, family and even individual scales. Applying a rapid appraisal technique, this chapter analyses the system of planning for climate adaptation as it relates to the achievement of adaptation outcomes within the Wet Tropics Cluster. It finds that some aspects of the system are healthier than others, and identifies several actions that regional NRM bodies may consider (either collectively or individually) to enhance adaptation outcomes by improving the planning system within the cluster.
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This paper examines discourses of male prostitution through an analysis of scientific texts. A contrast is drawn between nineteenth-century understandings of male prostitution and twentieth-century accounts of male prostitution. In contrast to female prostitution, male prostitution was not regarded as a significant social problem throughout the nineteenth century, despite its close association with gender deviation and social disorder. Changing conceptions of sexuality, linked with the emergence of the ‘adolescent’, drew scientific attention to male prostitution during the 1940s and 1950s. Research suggested that male prostitution was a problem associated with the development of sexual identity. Through the application of scientific techniques, which tagged and differentiated male prostitute populations, a language developed about male prostitution that allowed for normative assessments and judgements to be made concerning particular classes of male prostitute. The paper highlights how a broad distinction emerged between public prostitutes, regarded as heterosexual/masculine, and private prostitutes, regarded as homosexual/effeminate. This distinction altered the way in which male prostitution was understood and governed, allowing for male prostitution to be constituted as a public health concern.
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Rural crime has largely been understood through social disorganization theory. The dominance of this perspective has meant that most research into rural crime has tried to resolve perceived strains in communities, rather than analyze how social problems are constituted in rural places. Using Elias and Scotson's (1994) account of established-outsider relations, the paper examines how the organizational capacity of specific social groups is significant in determining the quality of crime-talk and responses to crime in isolated and rural settings. In particular social 'oldness' and notions of what constitutes 'community' are significant in determining what activities and individuals or groups are marked as features of crime-talk in these settings.