62 resultados para TOP-DOWN


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Two approaches are used for silk particle production: bottom up and top down. In the bottom up approach, different liquid-solid phase transfer techniques are adapted to fabricate particles from silk solution. In the top down approach, silk fibres are milled by various means to prepare ultrafine silk particles. Many important properties of particles such as size, geometry, porosity, stability and biodegradability are dependent on the specific methods of particle production. These properties influence drug loading and release, delivery modes, biocompatibility and their clearance from the body. Particle properties also determine biomechanical properties of particle reinforced composite scaffolds. Thus correlation between preparation, characterisation and application of silk particles for a specific biomedical application is critical. Progress made in this direction and challenges ahead are discussed in this chapter. © 2014 Woodhead Publishing Limited. All rights reserved.

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This paper describes an ePortfolio implementation strategy at Federation University Australia, Victoria (formerly the University of Ballarat). The authors combined a personal and practical viewpoint to elicit pitfalls, challenges, and recommendations for improvement. The paper is divided into three main areas in order to outline the experiments that occurred. The first section provides a standard literature review around ePortfolio adoption as well as a research-based analysis of available ePortfolio software at Australian universities. The second part depicts the University’s ePortfolio implementation strategy that focused on “test-to-production” and technology dissemination phases. This section is based on the authors’ personal viewpoint of ePortfolio adoption at a university where a “top-down management decision making model” (Slade, Murfin, & Readman, 2013, p. 178) was used. Third, the evaluation strategy is reported, which was based on similar research conducted at Australian universities (Hallam & Creagh, 2010; Hallam, Harper, Hauville, Creagh, & McAllister, 2009). This part is offered as a modest-scoped, mixed methods evaluation process. The paper extends on ePortfolio implementation strategies (Bell & White, 2013; Coffey & Ashford-Rowe, 2014; Jarrott & Gambrel, 2011; Lambert & Corrin, 2007; Ring & Ramirez, 2012; Slade et al., 2013) and software analysis (ACODE, 2011; Slade et al., 2013). Recommendations are made for the careful integration of pre- and post-rollout of ePortfolio programs with face-to-face ePortfolio tutor support, offering online resources and alternative portfolio-making options for students with poor broadband access.

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Silk fibroin has been widely employed in various forms as biomaterials for biomedical applications due to its superb biocompatibility and tunable degradation and mechanical properties. Herein, silk fibroin microparticles of non-mulberry silkworm species (Antheraea assamensis, Antheraea mylitta and Philosamia ricini) were fabricated via a top-down approach using a combination of wet-milling and spray drying techniques. Microparticles of mulberry silkworm (Bombyx mori) were also utilized for comparative studies. The fabricated microparticles were physico-chemically characterized for size, stability, morphology, chemical composition and thermal properties. The silk fibroin microparticles of all species were porous (∼5μm in size) and showed nearly spherical morphology with rough surface as revealed from dynamic light scattering and microscopic studies. Non-mulberry silk microparticles maintained the typical silk-II structure with β-sheet secondary conformation with higher thermal stability. Additionally, non-mulberry silk fibroin microparticles supported enhanced cell adhesion, spreading and viability of mouse fibroblasts than mulberry silk fibroin microparticles (p<0.001) as evidenced from fluorescence microscopy and cytotoxicity studies. Furthermore, in vitro drug release from the microparticles showed a significantly sustained release over 3 weeks. Taken together, this study demonstrates promising attributes of non-mulberry silk fibroin microparticles as a potential drug delivery vehicle/micro carrier for diverse biomedical applications.

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In 1997, the New Labour government inherited a ‘crisis’ in the UK National Health Service from the outgoing Conservative government. To address this perceived crisis, New Labour offered investment and, contrary to expectations, further neo-liberal health service reforms. In particular, the government extended the scope of performance management beyond financial numbers to encompass all aspects of managerial and organisational performance. Drawing on an analytics of government framework, this paper demonstrates how reforms were framed and given meaning through a framework of hierarchical accountability and centralised control. These panoptical arrangements relied on performance-management technologies of targets and ratings, which were linked to patient choice and a prospective funding system called ‘Payment by Results’. In turn, these top-down technologies disciplined knowledge, identity, and visibility and control of practice.

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When social and economic conditions change dramatically, status hierarchies in place for hundreds of years can crumble as marketization destabilizes once rigid boundaries. This study examines such changes in symbolic power through an ethnographic study of a village in North India. Marketization and accompanying privatization do not create an independent sphere where only money matters, but due to a mix of new socioeconomic motives, they produce new social obligations, contests, and solidarities. These findings call into question the emphasis in consumer research on top-down class emulation as an essential characteristic of status hierarchies. This study offers insights into sharing as a means of enacting and reshaping symbolic power within a status hierarchy. A new order based on markets and consumption is disrupting the old order based on caste. As the old moral order dissolves, so do the old status hierarchies, obligations, dispositions, and norms of sharing that held the village together for centuries. In the microcosm of these gains and losses, we may see something of the broader social and economic changes taking place throughout India and other industrializing countries.

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Apex predators perform important functions that regulate ecosystems worldwide. However, little is known about how ecosystem regulation by predators is influenced by human activities. In particular, how important are top-down effects of predators relative to direct and indirect human-mediated bottom-up and top-down processes? Combining data on species' occurrence from camera traps and hunting records, we aimed to quantify the relative effects of top-down and bottom-up processes in shaping predator and prey distributions in a human-dominated landscape in Transylvania, Romania. By global standards this system is diverse, including apex predators (brown bear and wolf), mesopredators (red fox) and large herbivores (roe and red deer). Humans and free-ranging dogs represent additional predators in the system. Using structural equation modelling, we found that apex predators suppress lower trophic levels, especially herbivores. However, direct and indirect top-down effects of humans affected the ecosystem more strongly, influencing species at all trophic levels. Our study highlights the need to explicitly embed humans and their influences within trophic cascade theory. This will greatly expand our understanding of species interactions in human-modified landscapes, which compose the majority of the Earth's terrestrial surface.

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In many network applications, the nature of traffic is of burst type. Often, the transient response of network to such traffics is the result of a series of interdependant events whose occurrence prediction is not a trivial task. The previous efforts in IEEE 802.15.4 networks often followed top-down approaches to model those sequences of events, i.e., through making top-view models of the whole network, they tried to track the transient response of network to burst packet arrivals. The problem with such approaches was that they were unable to give station-level views of network response and were usually complex. In this paper, we propose a non-stationary analytical model for the IEEE 802.15.4 slotted CSMA/CA medium access control (MAC) protocol under burst traffic arrival assumption and without the optional acknowledgements. We develop a station-level stochastic time-domain method from which the network-level metrics are extracted. Our bottom-up approach makes finding station-level details such as delay, collision and failure distributions possible. Moreover, network-level metrics like the average packet loss or transmission success rate can be extracted from the model. Compared to the previous models, our model is proven to be of lower memory and computational complexity order and also supports contention window sizes of greater than one. We have carried out extensive and comparative simulations to show the high accuracy of our model.

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Considerable uncertainties often surround the causes of long-term changes in population abundance. One striking example is the precipitous decline of southern sea lions (SSL; Otariaflavescens) at the Falkland Islands, from 80 555 pups in the mid 1930s to just 5506 pups in 1965. Despite an increase in SSL abundance over the past two decades, the population has not recovered, with the number of pups born in 2014 (minimum 4443 pups) less than 6% of the 1930s estimate. The order-of-magnitude decline is primarily attributed to commercial sealing in Argentina. Here, we test this established paradigm and alternative hypotheses by assessing (1) commercial sealing at the Falkland Islands, (2) winter migration of SSL from the Falkland Islands to Argentina, (3) whether the number of SSL in Argentina could have sustained the reported level of exploitation, and (4) environmental change. The most parsimonious hypothesis explaining the SSL population decline was environmental change. Specifically, analysis of 160 years of winter sea surface temperatures revealed marked changes, including a period of warming between 1930 and 1950 that was consistent with the period of SSL decline. Sea surface temperature changes likely influenced the distribution or availability of SSL prey and impacted its population dynamics. We suggest that historical harvesting may not always be the "smoking gun" as is often purported. Rather, our conclusions support the growing evidence for bottom-up forcing on the abundance of species at lower trophic levels (e.g., plankton and fish) and resulting impacts on higher trophic levels across a broad range of ecosystems.

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In Australia, applicants for admission to the legal profession must hold appropriate academic qualifications, and competently complete practical legal training (PLT). The author's research investigates institutional PLT practitioners' engagement with scholarship of teaching and learning (SoTL). The theoretical framework for the research draws on Bourdieu and Passeron's reflexive sociology of education and culture. This article focuses on responses to a paramount obligation proposition put to 34 PLT practitioners during semi-structured interviews: Might lawyers' paramount obligations to the court intersect with PLT practitioners' teaching and assessment practices? The proposition elicited responses and insights about field forces within the individual and organisational dimensions of teaching and learning in PLT. These include top-down/bottom-up pressures that impinge on PLT practitioners' engagement with SoTL.

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The evolution of polymer based nanoparticles as a drug delivery carrier via pharmaceutical nano/microencapsulation has greatly promoted the development of nano- and micro-medicine in the past few decades. Poly(lactide-co-glycolide) (PLGA) and chitosan, which are biodegradable and biocompatible polymers, have been approved by both the Food & Drug Administration (FDA) and European Medicine Agency (EMA), making them ideal biomaterials that can be advanced from laboratory development to clinical oral and parental administrations. PLGA and chitosan encapsulated nanoparticles (NPs) have successfully been developed as new oral drug delivery systems with demonstrated high efficacy. This review aims to provide a comprehensive overview of the fabrication of PLGA and chitosan particulate systems using nano/microencapsulation methods, the current progress and the future outlooks of the nanoparticulate drug delivery systems. Especially, we focus on the formulations and nano/micro-encapsulation techniques using top-down techniques. It also addresses how the different phases including the organic and aqueous ones in the emulsion system interact with each other and subsequently influence the properties of the drug delivery system. Besides, surface modification strategies which can effectively engineer intrinsic physicochemical properties are summarised. Finally, future perspectives and potential directions of PLGA and chitosan nano/microencapsulated drug systems are outlined.

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Saliency detection is critical to many applications in computer vision by eliminating redundant backgrounds. The saliency detection approaches can be divided into two categories, i.e., top-down and bottom-up. Among them, bottom-up models have attracted more attention due to their simple mechanisms. However, many existing bottom-up models are not robust to crowded backgrounds because of missing salient regions within feedforward frameworks which is often not effective for complex scenes. We tackle these problems by modifying and extending a bottom-up saliency detection model through three phases, (1) constructing a hierarchical sequence of images from the perspective of entropy, (2) estimated mid-level cues are used as feedback information, (3) subsequently generating saliency maps by global context and local uniqueness in a graph-based framework. We also compare the proposed bottom-up model with state-of-the-art approaches on two benchmark datasets to evaluate its saliency detection performance. The experimental results demonstrate that the proposed bottom-up saliency detection approach is not only robust to both cluttered and clean scenes, but also able to obtain objects with different scales.

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This thesis proposes two top-down approch frameworks to assess the Basel III countercyclical capital buffer. The empirical results demonstrate that sovereign sector distance-to-default and market illiquidity are more suitable indicator for guiding the decision of the buffer during both build-up and release phase than the official indicator, credit-to-GDP ratio. The findings in this thesis are important to help safeguard the globe financial system.

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In this article we focus upon the ways that “migrants” in Melbourne have used David Bowie to story and make sense of their arrival to Australia, often as refugees or as people looking for a better life. In relation to identity and belonging, some recent work on music fandom (Groene and Hettinger 2015; Lowe 2003), has imposed a meta-frame on the empirical method, substituting voices for a top-down analysis and interpretation. Our approach is to instead draw both upon auto-ethnography and to allow our fellow fans to “story” their own responses, in an attempt to get beneath the modes of feeling that music fandom ignites – situated within the narratives that people construct as they talk these stories. We argue that Bowie’s alternative and outsider status resonates keenly with people who find themselves “strangers” in a new land.

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Belinda’s research examined the adoption of a Health Promoting School (HPS) framework in an International School. The development of a carefully constructed and executed change message, and simultaneously using top-down and bottom-up approaches were critical to initiating change. Alternative strategies for establishing HPS in the international school context were identified.

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This thesis focuses on the problem of object detection under partial occlusion in complex scenes through exploring new bottom-up and top-down detection models to cope with object discontinuities and ambiguity caused by partial occlusion and allow for a more robust and adaptive detection of varied objects from different scenes.