980 resultados para ORIGINS


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Raman spectroscopy has been used to study a selection of vivianites from different origins. A band is identified at around 3480 cm-1 whose intensity is sample dependent. The band is attributed to the stretching vibration of Fe3+ OH units which are formed through the autooxidation of the vivianite minerals either by self-oxidation or by photocatalytic oxidation according to the reaction: (Fe2+)3(PO4)2·8H2O + 1/2O2 (Fe2+)3– x(Fe3+)x(PO4)2(OH)x·(8–x)H2O in which some of the water of crystallization is converted to hydroxyl anions. Complexity of the OH stretching region through the overlap of broad bands is reflected in the water HOH deformation modes at 1660 cm–1. Using the infrared bands at 3281, 3105 and 3025 cm–1, hydrogen bond distances of 2.734(5), 2.675(2) and 2.655(2) Å are calculated. Vivianites are characterised by an intense band at 950 cm–1 assigned to the PO4 symmetric stretching vibration. Low Raman intensity bands are observed at ~1077, ~1050, 1015 and ~ 985 cm–1 assigned to the phosphate PO4 antisymmetric stretching vibrations. Multiple antisymmetric stretching vibrations are due to the reduced tetrahedral symmetry. This loss of degeneracy is also reflected in the bending modes. Two bands are observed at ~ 423 and ~ 456 cm–1 assigned to the2bending modes. For the vivianites four bands are observed at ~ 584, ~ 571, ~ 545 and ~ 525 cm–1 assigned to the 4modes of vivianite.

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Purpose - This chapter examines individual and collective quests for authenticity, as experienced through consumption activities within an urban neighbourhood. It investigates the interplay between consumption experiences as authenticating acts and authoritative performances (Arnould and Price 2000), and considers the implications with regard to Zukin’s (2010) theories on urban authenticity, and how it may be experienced as new beginnings and origins. Methodology - The chapter is based on autoethnographic research that explores how interaction and identity definition within servicescapes can work to construct place-based community. Findings - It describes how a servicescape of new beginnings offered opportunities for individual authentication that also enabled personal identification with a specific cultural group. This authentication drew on the cultural capital embedded in such locations, including their association with gentrification. This is contrast with the collective identification offered by a servicescape operating as a place of exposure. This site of origins displayed the social practices of a different demographic, which worked to highlight a relational link between the authentication practices of the broader neighbourhood. These sites also worked cumulatively, to highlight the inauthenticities within my identification practices and offer opportunities for redress. Through this interplay it was possible to establish an authentic sense of neighbourhood that drew on its new beginnings and its origins, and was both individual and collective. Originality - Through the combination of urban and consumption-based perspectives of authenticity, and an autoethnographic methodology, this chapter offers a different insight into the ways identification with, and attachment to, a neighbourhood can develop through consumption experiences.

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This series of research vignettes is aimed at sharing current and interesting research findings from our team of international Entrepreneurship researchers. In this vignette, post-doctoral research fellow Dr Michael Stuetzer considers the effects and origins of balanced skills.

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At the core of our uniquely human cognitive abilities is the capacity to see things from different perspectives, or to place them in a new context. We propose that this was made possible by two cognitive transitions. First, the large brain of Homo erectus facilitated the onset of recursive recall: the ability to string thoughts together into a stream of potentially abstract or imaginative thought. This hypothesis is sup-ported by a set of computational models where an artificial society of agents evolved to generate more diverse and valuable cultural outputs under conditions of recursive recall. We propose that the capacity to see things in context arose much later, following the appearance of anatomically modern humans. This second transition was brought on by the onset of contextual focus: the capacity to shift between a minimally contextual analytic mode of thought, and a highly contextual associative mode of thought, conducive to combining concepts in new ways and ‘breaking out of a rut’. When contextual focus is implemented in an art-generating computer program, the resulting artworks are seen as more creative and appealing. We summarize how both transitions can be modeled using a theory of concepts which high-lights the manner in which different contexts can lead to modern humans attributing very different meanings to the interpretation of one concept.

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This thesis is an ethical and empirical exploration of the late discovery of genetic origins in two contexts, adoption and sperm donor-assisted conception. This exploration has two interlinked strands of concern. The first is the identification of ‘late discovery’ as a significant issue of concern, deserving of recognition and acknowledgment. The second concerns the ethical implications of late discovery experiences for the welfare of the child. The apparently simple act of recognition of a phenomenon is a precondition to any analysis and critique of it. This is especially important when the phenomenon arises out of social practices that arouse significant debate in ethical and legal contexts. As the new reproductive technologies and some adoption practices remain highly contested, an ethical exploration of this long neglected experience has the potential to offer new insights and perspectives in a range of contexts. It provides an opportunity to revisit developmental debate on the relative merit or otherwise of biological versus social influences, from the perspective of those who have lived this dichotomy in practise. Their experiences are the human face of the effects arising from decisions taken by others to intentionally separate their biological and social worlds, an action which has then been compounded by family and institutional secrecy from birth. This has been accompanied by a failure to ensure that normative standards and values are upheld for them. Following discovery, these factors can be exacerbated by a lack of recognition and acknowledgement of their concerns by family, friends, community and institutions. Late discovery experiences offer valuable insights to inform discussions on the ethical meanings of child welfare, best interests, parental responsibility, duty of care and child identity rights in this and other contexts. They can strengthen understandings of what factors are necessary for a child to be able to live a reasonably happy or worthwhile life.

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This is volume 1 in a series of four volumes about the origins of Australian football as it evolved in Victoria between 1858 and 1896. This volume addresses its very beginnings as an amateur sport and the rise of the first clubs. Invented by a group of Melbourne cricketers and sports enthusiasts, Australian Rules football was developed through games played on Melbourne's park lands and was originally known as "Melbourne Football Club Rules". This formative period of the game saw the birth of the first 'amateur heroes' of the game. Players such as T.W. Wills, H.C.A. Harrison, Jack Conway, George O'Mullane and Robert Murray Smith emerged as warriors engaged in individual rugby-type scrimmages. The introduction of Challenge Cups was an important spur for this burgeoning sport. Intense competition and growing rivalries between clubs such as Melbourne, South Yarra, Royal Park, and Geelong began to flourish and the game developed as a result. By the 1870s the game "Victorian Rules" had become the most popular outdoor winter sport across the state. In subsequent decades, rapid growth in club football occurred and the game attracted increasing media attention.

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Maize streak virus (MSV), which causes maize streak disease (MSD), is one of the most serious biotic threats to African food security. Here, we use whole MSV genomes sampled over 30 years to estimate the dates of key evolutionary events in the 500 year association of MSV and maize. The substitution rates implied by our analyses agree closely with those estimated previously in controlled MSV evolution experiments, and we use them to infer the date when the maize-adapted strain, MSV-A, was generated by recombination between two grass-adapted MSV strains. Our results indicate that this recombination event occurred in the mid-1800s, ∼20 years before the first credible reports of MSD in South Africa and centuries after the introduction of maize to the continent in the early 1500s. This suggests a causal link between MSV recombination and the emergence of MSV-A as a serious pathogen of maize. © 2009 SGM.

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We investigate the physical origins of etching observed during Ti diffusion. The relationship between observed etch depth and water vapor content in the annealing environment is quantified. The dynamics of the etching process are also identified. It is discovered that water vapor content is essential for etching and that there is a characteristic delay before etching is observed. From these observations we can conclude that the process is electrochemical in nature with ionic defects diffusing into the Ti strip from the lithium niobate and these defects catalyzing the dissociation of water into reactive ions.

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Three separate claims to originating the dawn service – a core element of the Australian Anzac Day ritual and sense of Australian national identity – circulate persistently in contemporary Australian culture. This article offers a critical comparative analysis of these claims, examining in particular the complex interactions between official and lay narratives as part of regional and state identity politics, conventions establishing validity and worth, and the ways in which these narratives incorporate and enable multiple origins. In the process it becomes clear that multiple narratives of origin are vital to a strong sense of spontaneous national identity.

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Objective Recently, Taylor et al. reported that use of the BrainLAB m3 microMLC, for stereotactic radiosurgery, results in a decreased out-of-field dose in the direction of leaf-motion compared to the outof- field dose measured in the direction orthogonal to leaf-motion [1]. It was recommended that, where possible, patients should be treated with their superior–inferior axes aligned with the microMLCs leafmotion direction, to minimise out-of-field doses [1]. This study aimed, therefore, to examine the causes of this asymmetry in outof- field dose and, in particular, to establish that a similar recommendation need not be made for radiotherapy treatments delivered by linear accelerators without external micro-collimation systems. Methods Monte Carlo simulations were used to study out-of-field dose from different linear accelerators (the Varian Clinacs 21iX and 600C and the Elekta Precise) with and without internal MLCs and external microMLCs [2]. Results Simulation results for the Varian Clinac 600C linear accelerator with BrainLAB m3 microMLC confirm Taylor et als [1] published experimental data. The out-of-field dose in the leaf motion direction is deposited by lower energy (more obliquely scattered) photons than the out-of-field dose in the orthogonal direction. Linear accelerators without microMLCs produce no asymmetry in out-offield dose. Conclusions The asymmetry in out-of-field dose previously measured by Taylor et al. [1] results from the shielding characteristics of the BrainLAB m3 microMLC device and is not produced by the linear accelerator to which it is attached.