7440 research outputs found
Sort by
Time-resolved microfluidic flow cytometry
No full textEmpirical thesis.Bibliography: pages 135-157.Chapter 1. Introduction -- Chapter 2. Instrumentation -- Chapter 3. Methodology -- Chapter 4. System evaluation -- Chapter 5. Multiplexing detection -- Chapter 6. Conclusions and perspectives -- References -- Appendices.Flow cytometry is extensively applied in life sciences and clinical practice for high-throughput identification and characterization of cells, particles or microorganisms suspended in fluid samples. However, conventional flow cytometry based on spectral detection suffers from two main disadvantages: interference from biological autofluorescence, and spectral crosstalk of fluorochromes. Time-resolved detection employing long-lived luminescent probes such as lanthanide complexes provides an effective strategy to overcome these issues. It effectively removes short-lived autofluorescence background arising from non-target specimens in the sample, resulting in high detection sensitivity and contrast. Multiplexing can be realised based on the luminescence lifetimes of the probes, avoiding spectral crosstalk between the detection channels.This thesis reports the design, development and demonstration of a time-resolved microfluidic flow cytometer (TRMFC) as a practical and low-cost technique aiming to achieve lifetime-based multiplexed biosensing. A microfluidic chip coupled with a piezoelectric transducer is used for two-dimensional acoustic focusing of the events at the centre of the flow channel. The sample flow rates are set so that sufficient signal from the long-decay luminescence can be acquired as targets transit the detection aperture, to ensure accurate lifetime measurement. The excitation source (i.e. UV LED) and detector (i.e. gatable PMT) are pulsed with a time-shift delay between them to discriminate the autofluorescent before luminescence signal detection.The current TRMFC system is able to achieve high counting efficiencies (>90%) of the luminescent targets passing through the microfluidic channel, and resolve lifetimes of individual targets at high accuracy (coefficient of variation ~2.4%). The acoustic focusing efficiency under varied flow velocity and the influence on time-resolved detection have been analysed in detail. The results indicate that a flow rate as high as 20 μl/min can be applied in the current system without affecting accurate counting of the events and measurement of their individual lifetime and intensity.Poisson statistics has been applied to calculate the overlap probability of two or more events presenting simultaneously in the detection aperture. A peak detection algorithm has been developed to resolve the overlap events containing two targets; whereas events with three and more targets overlapped with each other are discarded due to significantly increased computational complexity and reduced robustness for nonlinear fitting. The probability of three and more targets overlap is limited to <1% by proper configuration of key experimental parameters including the detection aperture size, the flow velocity and the sample concentration, so that optimum performance is achieved at highest sample throughput.Finally, a pilot multiplexing bioassay has been demonstrated using two cell lines stained with different europium complexes. Factors that influence the luminescence lifetimes and intensities of the stained cells, including different cell lines, cell growth phases, fixation of cells, chelate structures, ratio of chelators and Eu3+, and reaction solvents for the chelates, have been investigated experimentally. Samples containing the two distinct cell types have been successfully analysed using the TRMFC. This new technique, upon further optimisation, is expected to benefit on-site screening of fluidic samples containing multiple target populations, such as blood, urine and environmental water, opening a range of opportunities using lanthanide complex as biosensors for ultrasensitive biomedical diagnostics.KeyMode of access: World wide web1 online resource (xiv, 168 pages) graphs, table
A framework for savagery?: a thematic network analysis of the management of savagery and examination of its relation ship to Islamic State strategy in the West
No full textTheoretical thesis.Bibliography: pages 100-107.Introduction -- Chapter 1. - Historical context and conceptual framework -- Chapter 2. Literature review -- Chapter 3. Method and approach -- Chapter 4. MoS strategy and thematic network analysis -- Chapter 5. IS operational trends and analysis -- Chapter 6. Conclusion.Abu-Bakr-Naji's' The Management of Savagery' (MoS) is widely considered as a 'blueprint' for Islamic State' strategy. Indeed, both MoS themes and Islamic State' external operations incorporate principles of revolutionary warfare. However, despite correlations, Islamic State deviates from the strategic and systematic guidance articulated in MoS and appears to prioritise operational flexibility over doctrinal rigidity, often traversing through various phases of a politico-military strategy. This thesis finds Islamic State operations in the West are more opportunistic than strategic. What emerges from a comparative analysis of MoS themes and jihadist terrorist attacks between 2014 and 2018 is a strong correlation between themes of 'violence', 'vexation', 'small-scale operations', and the 'media battle' and broad operational trends. Yet these trends do not strictly follow MoS' structured approach. Rather, Islamic State strategy reflects the group's own adaptation of revolutionary warfare which has evolved over time and is relatively consistent with the group's ideological foundations1 online resource (123 pages) colour illustration
Catalan objects in categories
No full textTheoretical thesis.Bibliography: page 51.Chapter 1. Introduction and motivation -- Chapter 2. A first case -- Chapter 3. A generalisation in set -- Chapter 4. A generalisation for monoidal categories -- Chapter 5. Further research.The Catalan numbers 1, 2, 5, 14, 42, 132, . . . count all sorts of interesting objects: for example, thenth Catalan number enumerates both the set of Tn of rooted finitely branching trees with n + 1 vertices, and the set Bn of rooted binary trees with n + 1 leaves. In fact for each n, the sets Tn and Bn are in bijection in a natural way. The objective of this thesis is to study these bijections, and similar ones, through the lens of category theory. The set of rooted finitely branching trees can be characterised as an initial motor; where a motor is a monoid endowed with a endofunction (not preserving the monoid structure). The set of rooted binary trees can be characterised as an initial pointed magma; where a pointed magma is a set endowed with a constant and a binary operation. We first give an account of the bijection between rooted trees and binary trees which uses only the universal properties of the initial motor and the initial pointed magma. We then generalise this in various directions; our most general result identifies the initial T -motor with the initial pointed T -magma, when T is an arbitrary endofunctor of a closed monoidal category C ; here, a T -motor is a monoid X endowed with a mapping T X X , while a pointed T -magma is an object with a map I + TX ⊗ X X. We will also give numerous examples and applications.1 online resource (iii, 51 pages
Gestão de resíduos de equipamentos elétricos e eletrônicos (WEEE) na Austrália e no Brasil
No full textThesis by publication."This thesis is submitted in fulfilment of the requirements for the award of Doctor of Philosophy (Ph.D.) under cotutelle agreement between PPGE3M UFRGS, School of Engineering Macquarie University" -- title pageBibliography: pages 193-212.Chapter One. Introduction -- Chapter Two. Literature review -- Chapter Three. Paper 1 -- Chapter Four. Paper 2 -- Chapter Five. Paper 3 -- Chapter Six. Conclusions -- Consolidated reference list -- Appendices.Waste electrical and electronic equipment (e-waste) is a current global challenge due to its exponential growth, toxic potential and precious/rare materials in its composition lost when landfilled. These challenges make e-waste management crucial economically and environmentally. The ideal e-waste management approach is a matter of research given it currently varies greatly among countries and the world has not yet found an efficient and effective solution. This thesis studies two countries that share enough similarities (same territory size, similar e-waste generated per purchasing power and recent policy framework towards e-waste) and precise discrepancies to allow comparison: Australia and Brazil. Australia being a developed country that has defined the roles and responsibilities of e-waste stakeholders, and Brazil being a developing country that left most of it to free market. The thesis combines three individual manuscripts published in scientific journals: the first two characterize the current e-waste management in Brazil and Australia, respectively, showing the distribution of e-waste recyclers, the main collection channels and the processes being undertaken. They also relate specific management issues found and explain the international e-waste trade (what is exported and where to). The third paper uses quantitative information obtained in Australia to assess the international trade and explain why some WEEE are exported, while some are processed domestically. The results obtained allow to discuss the importance of regulations for e-waste management and to what extent free market can operate without compromising the environment. It is shown that collection in metropolitan areas and downstream recycling where infrastructure is available can be left to the free market, while collection in remote areas and downstream recycling where there is no infrastructure can only be achieved through regulations. First stage recycling, however, is dependable on the country's workforce cost. Where labor is cheap, it will be driven by free market and needs regulations only to prohibit environmentally damaging processes.Mode of access: World wide web1 online resource (xviii, 232 pages) diagrams, graphs, table
Nonparametric inference in the presence of biased sampling
No full textEmpirical thesis.Bibliography: pages 77-81.1. Preliminaries and background -- 2. Confidence interval for the MRL function based on length-biased data -- 3. Confidence interval based on length-biased and right-censored data -- 4.Discussion and future directions -- 5. Appendix I -- 6. Appendix II -- References.Life expectancy is a key concept in survival analysis. When communicating with non-statisticians, average remaining lifespan is a more meaningful and comprehensible measure than the survival probability or the hazard rate. Therefore our research is centered on the mean residual lifetime function.Survival data collected in a cohort of prevalent cases may be used to draw statistical inference. Since non-random sampling of subjects is involved, the data collected in this sampling scheme are biased. The most common case of this bias, occurring when the so-called stationarity assumption is satisfied, is called length-bias. While prospective prevalent cohort studies are commonly conducted to evaluate the progression of some disease overtime, observations of many other sampling schemes have been reported to be length-biased. It is often necessary to take into account loss to follow-up of subjects, that is, the presence of censored data.In this thesis, we study the problem of statistical inference (i.e. confidence interval) for length-biased data via the empirical likelihood method. The results are extended to construct a confidence interval for length-biased random censored data. The performance of these methods are illustrated through a simulation study and a data set obtained from a study of shrubs.Mode of access: World wide web1 online resource (xii, 81 pages) graphs, table
Global English, global identities, and the global world: perceptions of a group of Korean English language users
No full textTheoretical thesis.Bibliography: pages 298-325.Introduction -- 2. Literature review -- 3. Methodology -- 4. Interpreting globalisation -- 5. Interpreting English in the world -- 6. Discussion -- 7. Conclusion.While global flows of information can be considered to be co - constructed and dynamic in nature, these same cultural movements may be seen by some to be under the influence of more prominent global forces and their associated cultural assets, e.g. the US and English. Nevertheless, contemporary English users' increased global mobility, leading to more intensified cultural encounters can foreground more nuanced interpretations of the global world and its cultural cycles and dynamics. Essentially, viewed from Ulrich Beck's Cosmopolitan Perspective, the contemporary era is one of intensified online and offline global encounters that enables Global English users to take on more subjective globally critical dispositions. Therefore, this research is in response to current globalising trends where global values, knowledge, and identities are constructed through more unique individual experiences. Such perspectives allow for a more critical analysis of English's position in the world, how it is consumed, and ho w it and its users interrelate. Adopting a Cosmopolitan Perspective, this study investigated seven Korean English users' views and interpretations of globalisation flows and Global English, and their subsequent positioning to English with respect to their being L2 users of Global English. Attitudes towards globalisation trends, Global English culture, English's position in the world and in the Korean context, World Englishes, and global/local identities were discussed. To address these issues, a longitudinal qualitative case study approach was utilised. Five semi - structured interviews were conducted with the participants over a 10 - month period. Pre - interview prompts and post - interview reflection blogs were also employed, which aided in the consolidation and recursive element running through the data collection process.The main findings to emerge were as follows. First, global technological innovations, e.g. the Internet, were pin - pointed as being particularly significant in the contemporary world. Such pervasiveness of Internet usage was a main implicating factor in the participants' perspective that iv English is 'not the only way' to navigate and become familiar with the world. It s ubiquitous usage was also highlighted as significantly contributing to a more dynamically woven and interrelating international culture rather than one interpreted through simplistic cultural polarities. Second , while the participants displayed open attitudes towards English variety (WEs), it was rather an acceptance of linguistic nuance as a representation of cultural background than legitimacy of alternative varieties of English. Subsequently Standard English should maintain adherence to native English speaker norms; albeit, global communicative competence among English's many users bore more prominence in this decision than one of native - centred ideology. Third, within the Korean context, the participants unanimously observed a disjuncture between the English received within Korean education system and the English needed for a more globally engaged Korean populace. Their views here also contributed to their acceptance of Korean English, as being a representation of Korean global engagement and agency. Lastly, while the participants displayed a sense of ownership and appropriation of English, such a relationship with the language did not necessarily fact or into their self - described global identities and orientations. Global knowledge and personal experiences were better descriptors for these orientations. Such perceptions bring into focus the complex processes involved in the construction of global dispositions and identities - certainly, English is a mitigating factor, but is one among many. The findings overall, suggest that as an outcome of increased global mobility, English users are forming more critical nuanced dispositions towards English, the global context, and its situatedness therein. Positioning oneself to native English speaker practices does not concurrently mean one is positioning oneself to native imperialistic ideologies. While insights revealed here certainly shine a spotlight on the Korean English education system, findings overall have implications for English education worldwide, in that, more awareness needs to be employed in terms of English learners more global active engagement.1 online resource (x, 349 pages
Fluorescent sensors for biosensing applications: immunosensors for mycotoxins and aptasensors for interferon-gamma
No full textThesis by publication."School of Engineering, Macquarie University ; Tianjin University of Science and Technology ; Australian Nuclear Science and Technology Organisation (ANSTO)" -- title page.Bibliography: pages 140-152.In this thesis, recent advances in the development of fluorescent sensors for the detection of mycotoxins and interferon-gamma (IFN-γ) were summarized. Three CdTe/CdS/ZnS quantum dot (QD)-based fluorescence immunoassays were developed for monitoring two types of mycotoxins: zearalenone (ZEN) and aflatoxin B1 (AFB1), and different fluorescence aptasensing strategies were developed to explore the detection capability of an anti-IFN-γ aptamer.A novel quantitative fluorescence immunoassay (FLISA) and a rapidly responding semi-quantitative fluorescent immunochromatographic test strip (ICTS) were established for the detection of ZEN in maize. The detection limit (LOD) of FLISA was determined to be 0.012 ng/mL in maize, with a dynamic range from 0.038 to 0.977 ng/mL. The rapid ICTS had a visual LOD of 1.5 ng/mL in maize extract.Two novel magnetic nanobeads-based fluoroimmunoassays were designed for sensitive detection of ZEN in cereals. Under optimal conditions, concentration as low as 0.019 ng/mL and 0.049 ng/mL ZEN could be detected in the extract solution for the first capture last react (FCLR) procedure and first react last capture (FRLC) procedure, respectively. The present methods were further performed for detection of ZEN in real cereal samples, and the LODs were 0.6 μg/kg and 1.5 μg/kg in the FCLR and FRLC, respectively. It showed that the proposed fluoroimmunoassays have great potential in bioanalysis.A simple FLISA was developed based on CdTe/CdS/ZnS QD for monitoring AFB1 in cereals. The proposed FLISA displayed a broad detection of AFB1 ranging from 0.08 to 1.97 ng/mL with a low LOD of 0.01 ng/mL. Moreover, the immunoglobulin genes of the anti-AFB1 Fab were cloned, and the recombinant Fab antibody for AFB1was prepared with a Kd value of 1.09×10-7 mol/L. To investigate the interactions between the antibody and AFB1, molecular dynamic simulation and quantum-chemical computation were performed on the Fab-fragment homology model. The analysis results showed that hydrogen bonds formation, Pi-alkyl interactions, and van der Waals interactions played the most important roles in antibody recognition.A strand displacement strategy for IFN-γ was developed by introducing three different complementary strands and two different signal/quencher pairs. The Texas red/BHQ2-based sensor demonstrated the best equilibrium binding constants of 21.87 ng/mL to IFN-γ. To improve the sensitivity of this aptamer-based sensor, a hybridization chain reactions amplification strategy was introduced, yielding a 12-fold improved sensitivity of 0.45 ng/mL. In addition, a fluorescent optical fiber aptasensor was developed for IFN-γ sensoring based on the strand displacement strategy.Mode of access: World wide web1 online resource (110 pages) illustrations (some colour
The effect of drawdown on the movement of groundwater invertebrates
No full textEmpirical thesis.Includes bibliographical references.Chapter 1. Literature review -- Chapter 2. Aims and hypotheses -- Chapter 3. Methods -- Chapter 4. Results -- Chapter 5. Discussion -- Chapter 6. Conclusion.Groundwater abstraction is a global problem limiting water resources and impacting dependent ecosystems. Groundwater invertebrates provide important services in their ecosystems. This study aims to clarify the role of sediment characteristics, invertebrate traits and drawdown rate on the response of groundwater invertebrates to water level changes. Column experiments using one of three sediment types and two groundwater invertebrate species were used with three drawdown rates. Hypotheses tested are: 1) coarse sediments and slower rates best facilitate the downward movement of invertebrates, 2) copepods and syncarids will differ in their downwards movement and 3) coarse sediment and fast rates will best facilitate the downwards movement of dead copepods. It was found that: 1) the proportion of copepods and syncarids stranded was not significantly different for the drawdown rates or sediment sizes, 2) copepods and syncarids were not found to differ significantly in their ability to move downwards and 3) sediment size and drawdown rate had no significant effect on the distance travelled by dead copepods. 11 % of copepods in the drawdown columns were stranded across all sediment types and rates, while 5 % of syncarids were stranded in the large sediment across all rates. While no statistically significant results were found the results here suggest that stranding does occur despite some capacity for invertebrates to follow a declining water table. The number of invertebrates stranded here under these conditions suggests that management of groundwater abstraction is needed to protect groundwater biodiversity and groundwater ecosystems.Mode of access: World wide web1 online resource (unpaged) colour illustration
Theodosius II and his image: three case studies in imperial presentation, ceremonial and reception
No full textTheoretical thesis.Bibliography: pages 142-157.Introduction -- The Eastern Theodosians -- Theodosius II and Constantinople -- Theodosius II and the West -- Conclusion -- Bibliography.Theodosius II (402-450 AD) was a non-campaigning sedentary emperor who lived and ruled the majority of his life within the city walls of Constantinople. He was orphaned and became sole Emperor at aged seven after the death of his father, Arcadius, in 408 and would continue to reign in the East successfully for a further forty-two years. Despite the limitations and anxieties associated with child-emperor rule, there is no clear evidence to suggest his position was ever contested nor his role as emperor ever questioned. This thesis will analyse three key components of the emperor’s reign to consider how the Eastern Theodosian regime first adapted and later developed traditional imperial presentation to better suit their unique situation of an emperor ruling the empire from such a young age without any adult familial support.The first case study examines the contemporary presentation and long-term reception of the public image of the Eastern branch of the Theodosian family. It will highlight the earliest identifiable establishment of this image in 414, after the proclamation of perpetual virginity by the emperor’s sisters and Pulcheria’s elevation to Augusta, and assess how it grew and developed alongside the family. The second case study assesses, through five examples, the active role Theodosius II played in the ceremonial life of Constantinople. It will highlight not only how this emperor reinvented traditional elements in imperial performance, but will also show the consistent portrayal of his behaviour in the sources that range from contemporary accounts to the ninth century. Finally, the third case study analyses the portrayal of Theodosius II as the father figure to Western emperor Valentinian III, his young cousin. This case study assesses three key events, the Eastern military expedition to install Valentinian III onto the Western throne between 424 and 425, the marriage of Theodosius II’s only surviving child, Licinia Eudoxia to the Western emperor in 437, and the proclamation of the Theodosian Code a year later, to show the ongoing development of this image throughout this period. Through these three case studies, this thesis will argue that Theodosius II was not only an active participant in his long reign, but also successfully established a new form of active leadership – one based primarily within the imperial city and amongst its citizenry.Mode of access: World wide web1 online resource (xi, 157 pages
Connecting people and nature in the Kavango-Zambezi Transfrontier Conservation Area: a study of power, scale and multiple perspectives in Southern Africa
No full textTheoretical thesis.Bibliography: pages 239-272.Chapter 1. Getting to know the thesis -- Chapter 2. Getting to know the research -- Chapter 3. Power, scale and multiple perspectives in natural resource management and nature conservation -- Chapter 4. Conservation without boundaries? Cross-scale challenges and opportunities of introducing a ‘new’ scale – KAZA-TFCA -- Chapter 5. Inter-national politics, conservation and the Kavango-Zambezi Transfrontier Conservation Area (KAZA-TFCA) : how the political situation in Zimbabwe is influencing conservation strategies within KAZA-TFCA -- Chapter 6. Beyond KAZA-TFCA : local community engagement in conservation in North Western Zimbabwe -- Chapter 7. Context, Scale and power : implications for participation, nature and people -- Chapter 8. Conclusions and critical reflections -- Appendices -- References.Over the past two decades, the use of Transfrontier Conservation Areas (TFCAs) as a strategy to preserve Southern Africa’s natural heritage has increased. TFCAs bestride the borders of two or more countries and are jointly managed by the countries involved for conservation purposes. However, TFCAs are critiqued for side-lining certain natural resource users, particularly local communities (Borrini & Jaireth 2007, Ramutsindela 2005, Ramutsindela 2004, Leach et al. 1999). A growing body of research shows that protected areas and conservation strategies cannot protect natural resources in the long term without involving local communities in planning and implementation (Lele et al. 2010).This thesis uses a case study of the Kavango-Zambezi Transfrontier Conservation Area (KAZA-TFCA) to examine power relations that occur at multiple scales in nature conservation. KAZA-TFCA is the world’s largest TFCA, encompassing 5 nation-states in Southern Africa - Angola, Botswana, Namibia, Zambia and Zimbabwe. Guided by qualitative data, this thesis explores the multiple perspectives of different KAZA-TFCA stakeholders – human and non-human.Specifically, the thesis analyses KAZA-TFCA through three scaled lenses. Firstly, it focuses on the creation and implementation of KAZA-TFCA itself as a new regional scale of conservation governance. Secondly, it focuses on the role of the nation-state within KAZA-TFCA through the lens of one of KAZA-TFCA’s key players – Zimbabwe. Finally, it focuses on the north-west sector of Zimbabwe to enable a more nuanced local understanding of how power flows through and shapes human and non-human relationships in KAZA-TFCA.Findings suggest that processes occurring at different scales and involving different stakeholders and non-stakeholders brush up against each other and directly affect what is happening within the TFCA. By examining how different actors from different positions of power and authority engage with conservation processes within KAZA-TFCA, the thesis reveals the contradictory and consonant practices that are shaping conservation and development in KAZA-TFCA. The results illustrate how power and scale interrelate and result in exclusionary conservation practices in transboundary conservation, especially exclusion of local – human and non-human - communities. The thesis contributes to emerging debates on power and participation in nature conservation spheres and opens spaces for rethinking human and non-human relationships.Mode of access: World wide web1 online resource (xvii, 291 pages) colour illustrations, colour map