170 resultados para sphere packings


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The use of adherent monolayer cultures have produced many insights into melanoma cell growth and differentiation, but often novel therapeutics demonstrated to act on these cells are not active in vivo. It is imperative that new methods of growing melanoma cells that reflect growth in vivo are investigated. To this end, a range of human melanoma cell lines passaged as adherent cultures or induced to form melanoma spheres (melanospheres) in stem cell media have been studied to compare cellular characteristics and protein expression. Melanoma spheres and tumours grown from cell lines as mouse xenografts had increased heterogeneity when compared with adherent cells and 3D-spheroids in agar (aggregates). Furthermore, cells within the melanoma spheres and mouse xenografts each displayed a high level of reciprocal BRN2 or MITF expression, which matched more closely the pattern seen in human melanoma tumours in situ, rather than the propensity for co-expression of these important melanocytic transcription factors seen in adherent cells and 3D-spheroids. Notably, when the levels of the BRN2 and MITF proteins were each independently repressed using siRNA treatment of adherent melanoma cells, members of the NOTCH pathway responded by decreasing or increasing expression, respectively. This links BRN2 as an activator, and conversely, MITF as a repressor of the NOTCH pathway in melanoma cells. Loss of the BRN2-MITF axis in antisense-ablated cell lines decreased the melanoma sphere-forming capability, cell adhesion during 3D-spheroid formation and invasion through a collagen matrix. Combined, this evidence suggests that the melanoma sphere-culture system induces subpopulations of cells that may more accurately portray the in vivo disease, than the growth as adherent melanoma cells.

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Niklas Luhmann's theory of social systems has been widely influential in the German-speaking countries in the past few decades. However, despite its significance, particularly for organization studies, it is only very recently that Luhmann's work has attracted attention on the international stage as well. This Special Issue is in response to that. In this introductory paper, we provide a systematic overview of Luhmann's theory. Reading his work as a theory about distinction generating and processing systems, we especially highlight the following aspects: (i) Organizations are processes that come into being by permanently constructing and reconstructing themselves by means of using distinctions, which mark what is part of their realm and what not. (ii) Such an organizational process belongs to a social sphere sui generis possessing its own logic, which cannot be traced back to human actors or subjects. (iii) Organizations are a specific kind of social process characterized by a specific kind of distinction: decision, which makes up what is specifically organizational about organizations as social phenomena. We conclude by introducing the papers in this Special Issue. Copyright © 2006 SAGE.

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This chapter describes current trends in the global media environment, with a focus on their implications for the management of public agendas and political processes. It assesses the extent to which trends such as the growth of the blogosphere, "citizen journalism," and other forms if user-generated content, have complicated and problematized news and agenda management as engaged in by both media and political elites. It argues that, in large part due to the rise of the internet and the proliferation if online producers of information and commentary, alongside 24-hour news channels such as CNN and Al Jazeera, political and social actors today face a much more complex, chaotic communication environment than ever bifore, an environment characterized as one of cultural chaos. Having outlined the roots of this trend in the emergence of an expanded, globalized public sphere, the chapter goes on to ask if elite control over the political agenda has been eroded, and if it has, what the consequences for governmmt and the exercise if power might be. Can authoritarian regimes in China, the Middle East, and elsewhere survive the onset if internet-fueled global journalism, for example? In a political environment where public opinion is driven and buffeted by news coverage if unprecedented speed and volume, can democratic governments retain sufficient control over decision- and policy-making processes to enable competent social administration al'ld political management? Can the citizens of contemporary democracies use the emerging media environment to enhance elite accountability and strengthen the democratic process? The chapter concludes that the changing global media environment has the potmtial to strengthen democratic processes, though there is no sil'lgle template for the impact of the internet and other new media on specific countries.

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Purpose: James Clerk Maxwell is usually recognized as being the first, in 1854, to consider using inhomogeneous media in optical systems. However, some fifty years earlier Thomas Young, stimulated by his interest in the optics of the eye and accommodation, had already modeled some applications of gradient-index optics. These applications included using an axial gradient to provide spherical aberration-free optics and a spherical gradient to describe the optics of the atmosphere and the eye lens. We evaluated Young’s contributions. Method: We attempted to derive Young’s equations for axial and spherical refractive index gradients. Raytracing was used to confirm accuracy of formula. Results: We did not confirm Young’s equation for the axial gradient to provide aberration-free optics, but derived a slightly different equation. We confirmed the correctness of his equations for deviation of rays in a spherical gradient index and for the focal length of a lens with a nucleus of fixed index surrounded by a cortex of reducing index towards the edge. Young claimed that the equation for focal length applied to a lens with part of the constant index nucleus of the sphere removed, such that the loss of focal length was a quarter of the thickness removed, but this is not strictly correct. Conclusion: Young’s theoretical work in gradient-index optics received no acknowledgement from either his contemporaries or later authors. While his model of the eye lens is not an accurate physiological description of the human lens, with the index reducing least quickly at the edge, it represented a bold attempt to approximate the characteristics of the lens. Thomas Young’s work deserves wider recognition.

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Very little has been written on charitable laws in Fiji to date. Most of the organisations in Fiji seek incorporation under the pre-independence legislation dealing with charities, the Charitable Trusts Act (Cap 67). This Act is the basis of this paper. The key provisions of the Act are discussed in this paper. Recently serious questions have been raised on the status of charitable bodies with the de-registration of one of the registered charities (the Citizens’ Constitutional Forum (CCF)) for political activity. This paper also provides an insight into the CCF ‘saga’, which goes to the ‘heart’ of the Act and examines the serious questions that are raised in interpreting the provisions in the Act. In the concluding part, various issues of reform in the charity sphere are also proposed.

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Monodisperse silica nanoparticles were synthesised by the well-known Stober protocol, then dispersed in acetonitrile (ACN) and subsequently added to a bisacetonitrile gold(I) coordination complex ([Au(MeCN)2]?) in ACN. The silica hydroxyl groups were deprotonated in the presence of ACN, generating a formal negative charge on the siloxy groups. This allowed the [Au(MeCN)2]? complex to undergo ligand exchange with the silica nanoparticles and form a surface coordination complex with reduction to metallic gold (Au0) proceeding by an inner sphere mechanism. The residual [Au(MeCN)2]? complex was allowed to react with water, disproportionating into Au0 and Au(III), respectively, with the Au0 adding to the reduced gold already bound on the silica surface. The so-formed metallic gold seed surface was found to be suitable for the conventional reduction of Au(III) to Au0 by ascorbic acid (ASC). This process generated a thin and uniform gold coating on the silica nanoparticles. The silica NPs batches synthesised were in a size range from 45 to 460 nm. Of these silica NP batches, the size range from 400 to 480 nm were used for the gold-coating experiments.

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The Time magazine ‘Person of theYear’ award is a venerable institution. Established by Time’s founder Henry Luce in 1927 as ‘Man of the Year’, it is an annual award given to ‘a person, couple, group, idea, place, or machine that ‘for better or for worse ... has done the most to influence the events of the year’ (Time 2002, p. 1). In 2010, the award was given to Mark Zuckerberg, the founder and CEO of the social networking site Facebook.There was, however, a strong campaign for the ‘People’s Choice’ award to be given to Julian Assange, the founder and editor-in-chief of Wikileaks, the online whistleblowing site. Earlier in the year Wikileaks had released more than 250 000 US government diplomatic cables through the internet, and the subsequent controver- sies around the actions of Wikileaks and Assange came to be known worldwide as ‘Cablegate’. The focus of this chapter is not on the implications of ‘Cablegate’ for international diplomacy, which continue to have great significance, but rather upon what the emergence of Wikileaks has meant for journalism, and whether it provides insights into the future of journalism. Both Facebook and Wikileaks, as well as social media platforms such as Twitter and YouTube, and independent media practices such as blogging, citizen journalism and crowdsourcing, are manifestations of the rise of social media, or what has also been termed web 2.0.The term ‘web 2.0’ was coined by Tim O’Reilly, and captures the rise of online social media platforms and services, that better realise the collaborative potential of digitally networked media. They do this by moving from the relatively static, top-down notions of interactivity that informed early internet development, towards more open and evolutionary models that better harness collective intelligence by enabling users to become the creators and collaborators in the development of online media content (Musser and O’Reilly 2007; Bruns 2008).

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The possibility of a surface inner sphere electron transfer mechanism leading to the coating of gold via the surface reduction of gold(I) chloride on metal and semi-metal oxide nanoparticles was investigated. Silica and zinc oxide nanoparticles are known to have very different surface chemistry, potentially leading to a new class of gold coated nanoparticles. Monodisperse silica nanoparticles were synthesised by the well known Stöber protocol in conjunction with sonication. The nanoparticle size was regulated solely by varying the amount of ammonia solution added. The presence of surface hydroxyl groups was investigated by liquid proton NMR. The resultant nanoparticle size was directly measured by the use of TEM. The synthesised silica nanoparticles were dispersed in acetonitrile (MeCN) and added to a bis acetonitrile gold(I) co-ordination complex [Au(MeCN)2]+ in MeCN. The silica hydroxyl groups were deprotonated in the presence of MeCN generating a formal negative charge on the siloxy groups. This allowed the [Au(MeCN)2]+ complex to undergo ligand exchange with the silica nanoparticles, which formed a surface co-ordination complex with reduction to gold(0), that proceeded by a surface inner sphere electron transfer mechanism. The residual [Au(MeCN)2]+ complex was allowed to react with water, disproportionating into gold(0) and gold(III) respectively, with gold(0) being added to the reduced gold already bound on the silica surface. The so-formed metallic gold seed surface was found to be suitable for the conventional reduction of gold(III) to gold(0) by ascorbic acid. This process generated a thin and uniform gold coating on the silica nanoparticles. This process was modified to include uniformly gold coated composite zinc oxide nanoparticles (Au@ZnO NPs) using surface co-ordination chemistry. AuCl dissolved in acetonitrile (MeCN) supplied chloride ions which were adsorbed onto ZnO NPs. The co-ordinated gold(I) was reduced on the ZnO surface to gold(0) by the inner sphere electron transfer mechanism. Addition of water disproportionated the remaining gold(I) to gold(0) and gold(III). Gold(0) bonded to gold(0) on the NP surface with gold(III) was reduced to gold(0) by ascorbic acid (ASC), which completed the gold coating process. This gold coating process of Au@ZnO NPs was modified to incorporate iodide instead of chloride. ZnO NPs were synthesised by the use of sodium oxide, zinc iodide and potassium iodide in refluxing basic ethanol with iodide controlling the presence of chemisorbed oxygen. These ZnO NPs were treated by the addition of gold(I) chloride dissolved in acetonitrile leaving chloride anions co-ordinated on the ZnO NP surface. This allowed acetonitrile ligands in the added [Au(MeCN)2]+ complex to surface exchange with adsorbed chloride from the dissolved AuCl on the ZnO NP surface. Gold(I) was then reduced by the surface inner sphere electron transfer mechanism. The presence of the reduced gold on the ZnO NPs allowed adsorption of iodide to generate a uniform deposition of gold onto the ZnO NP surface without the use of additional reducing agents or heat.

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The return of emotions to debates about crime and criminal justice has been a striking development of recent decades across many jurisdictions. This has been registered in the return of shame to justice procedures, a heightened focus on victims and their emotional needs, fear of crime as a major preoccupation of citizens and politicians, and highly emotionalised public discourses on crime and justice. But how can we best make sense of these developments? Do we need to create "emotionally intelligent" justice systems, or are we messing recklessly with the rational foundations of liberal criminal justice? This volume brings together leading criminologists and sociologists from across the world in a much needed conversation about how to re-calibrate reason and emotion in crime and justice today. The contributions range from the micro-analysis of emotions in violent encounters to the paradoxes and tensions that arise from the emotionalisation of criminal justice in the public sphere. They explore the emotional labour of workers in police and penal institutions, the justice experiences of victims and offenders, and the role of vengeance, forgiveness and regret in the aftermath of violence and conflict resolution. The result is a set of original essays which offer a fresh and timely perspective on problems of crime and justice in contemporary liberal democracies.

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It has now been over a decade since the concept of creative industries was first put into the public domain by the Blair Labour government’s Creative Industries Mapping Documents in Britain. The concept has gained traction globally, but it has also been understood and developed in different ways in Europe, Asia, Australia, New Zealand, and North America, as well as through international bodies such as UNCTAD and UNESCO. A review of the policy literature reveals that although questions and issues remain around definitional coherence, there is some degree of consensus emerging about the size, scope, and significance of the sectors in question in both advanced and developing economies. At the same time, debate about the concept remains highly animated in media, communication, and cultural studies, with its critics dismissing the concept outright as a harbinger of neoliberal ideology in the cultural sphere. This article couches such critiques in light of recent debates surrounding the intellectual coherence of the concept of neoliberalism, arguing that this term itself possesses problems when taken outside of the Anglo-American context in which it originated. It is argued that issues surrounding the nature of participatory media culture, the relationship between cultural production and economic innovation, and the future role of public cultural institutions can be developed from within a creative industries framework and that writing off such arguments as a priori ideological and flawed does little to advance debates about twentieth-century information and media culture.

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Phenomenography is a qualitative research approach that seeks to explore variation in how people experience various aspects of their world. Phenomenography has been used in numerous information research studies that have explored various phenomena of interest in the library and information sphere. This paper provides an overview of the phenomenographic method and discusses key assumptions that underlie this approach to research. Aspects including data collection, data analysis and the outcomes of phenomenographic research are also detailed. The paper concludes with an illustration of how phenomenography was used in research to investigate students’ experiences of web-based information searching. The results of this research demonstrate how phenomenography can reveal variation, making it possible to develop greater understanding of the phenomenon as it was experienced, and to draw upon these experiences to improve and enhance current practice.

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The elastic properties of 1D nanostructures such as nanowires are often measured experimentally through actuation of the nanowire at its resonance frequency, and then relating the resonance frequency to the elastic stiffness using elementary beam theory. In the present work, we utilize large scale molecular dynamics simulations to report a novel beat phenomenon in [110]oriented Ag nanowires. The beat phenomenon is found to arise from the asymmetry of the lattice spacing in the orthogonal elementary directions of the [110] nanowire, i.e. the [-110] and [001] directions, which results in two different principal moments of inertia. Because of this, actuations imposed along any other direction are found to decompose into two orthogonal vibrational components based on the actuation angle relative to these two elementary directions, with this phenomenon being generalizable to <110> FCC nanowires of different materials (Cu, Au, Ni, Pd and Pt). The beat phenomenon is explained using a discrete moment of inertia model based on the hard sphere assumption, the model is utilized to show that surface effects enhance the beat phenomenon, while the effect is reduced with increasing nanowires cross-sectional size or aspect ratio. Most importantly, due to the existence of the beat phenomena, we demonstrate that in resonance experiments only a single frequency component is expected to be observed, particularly when the damping ratio is relatively large or very small. Furthermore, for a large range of actuation angles, the lower frequency is more likely to be detected than the higher one, which implies that experimental predictions of Young’s modulus obtained from resonance may in fact be under predictions. The present study therefore has significant implications for experimental interpretations of Young’s modulus as obtained via resonance testing.

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This article considers the impact of the WikiLeaks organisation in relation to debates around the defence of national security and free speech, global media citizenship and the emerging dynamics of the global public sphere. Building on the author’s previous work on political communication, journalism and ‘cultural chaos’, it explores the implications of WikiLeaks for emerging conceptions and definitions of journalism, and for the changing structure of media–politics power relations at the global level, against the background of three trends: democratisation, declining deference and digitalisation.

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This paper explores the process of introducing Digital Storytelling (DST) workshop practice to Turkey through a project called “Digital Stories from Amargi Women”, which was part of my Ph.D. research in the Creative Industries Faculty, Queensland University of Technology, Australia. In the resulting dissertation, I examined the potential of Digital Storytelling workshop practice as a means to promote agency and self-expression in a feminist activist organization (such as Amargi Women), focusing in particular on whether or not Digital Storytelling can be used as a change agent – as a tool for challenging the idea of a single public sphere in ways that make it more inclusive of women’s participation. In order to explore the issue in depth, my thesis engaged with feminist scholarship’s critiques of the public/private dichotomy, as well as the concept of gender. The conducted workshops, the resulting digital stories, and in-depth interviews were analyzed to seek connections between these topics and narrative identity. The results indicated that the participating women defined new activist usages for digital stories, as well as their overall activated networking habits in the DST workshop settings. Digital Stories from Amargi Women became the first Digital Storytelling project that aimed to enable women’s participation in Turkey through facilitating a co-creative environment where the participants could share their stories and learn digital skills that they could make use of after the workshops.