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Comparative analysis of reactive mercury measurement methodology and environmental correlates in Australia
No full textEmpirical thesis.Bibliography: pages 52-57.Chapter 1. Introduction -- Chapter 2. Literature review -- Chapter 3. Research methodology -- Chapter 4. RM method comparison -- Chapter 5. Tekran measurement uncertainties -- Chapter 6. Environmental influences -- Chapter 7. Conclusions -- Appendices.Accurate quantification of atmospheric mercury (Hg) is critical for understanding the Hg biogeochemical cycle and for the development of effective policy and management. However, measurement uncertainties as well as oxidation chemistry and other environmental influences make accurate quantification difficult. A method comparison between the Tekran speciation system (2537/1130/1135) and the University of Nevada Reno Reactive Mercury Active System (UNRRMAS) is provided for the first time within the Sydney urban environment, which ran for a total of 9 months. It was found that GOM collected by the Tekran speciation system and RM by the CEMs within the UNRRMAS collected mean concentrations of 18.21 ± 10.56 pg m-3 and 14.57 ± 5.45 pg m-3, respectively. These methods were found to be comparable during the study. An investigation into a number of environmental parameters at the MQ AWS site found there to be no observed relationship with O3 chemistry or other environmental parameters under linear regression analysis, suggesting that they exert little influence on RM concentrations. However, it is suggested that synoptic and mesoscale circulation patterns may play a key role in the concentration and dispersal of RM at the site, which is thought to be due to the unique topographical and climatological characteristics of the Sydney Basin.Mode of access: World wide web1 online resource (vi, 64 pages) colour illustration
Nutraceutical properties of whole dried sugarcane extracts studied by proteomics
No full textTheoretical thesis.Bibliography: pages 167-197Chapter 1. Introduction -- Chapter 2. Regulation of inflammatory mediators by dried sugarcane extracts in an in vitro colon cancer cell model of lps-induced inflammation -- Chapter 3. Phosphoproteomics analysis of cell signalling associated with dried sugarcane extracts in an in vitro colon cancer cell model of LPS-induced inflammation -- Chapter 4. Invivo supplementation of whole dried sugarcane in a HFD mouse model -- Chapter 5. General discussion and future directions.Many chronic diseases are associated with the activation of inflammatory mediators. This can lead to excessive release of pro-inflammatory cytokines and the generation of reactive oxygen species (ROS). Some nutraceuticals are rich in polyphenols providing strong antioxidant attributes which have been reported to counteract some of the deleterious effects of ROS. However, cellular mechanisms underlying nutraceutical therapeutic properties are often not well elucidated. In this thesis, the anti-inflammatory properties of the nutraceutical, whole dried sugarcane (WDS), was investigated using proteomic techniques. Chemical assays of WDS ethanol extracts (WDS EE) showed the presence of polyphenols and flavonoids conferring potent antioxidant activity. In lipopolysaccharide (LPS)-stimulated SW480 colon cancer cells, WDS EE reversed the phosphorylation of NFκB and inhibited the secretion of IL-8 in a mechanism shown to be dependent of C-Raf and AKT phosphorylation. Mass spectrometry (MS)-based proteomics using label-free SWATH-MS demonstrated WDS EE to alter the expression of oxidative stress mediators FOXRED1 and the selenoprotein SELH, amongst others. Based on protein expression, prediction analysis proposed the down-regulation of NFκB pathway members TLR2, TLR4, NIK and IκB. In the same model, phosphoproteomics studies indicated that WDS EE interferes in the phosphorylation of cell stress regulator proteins c-Jun, EGFR, PKA, PKCβ and SIRT1, interpreted as regulating anti-inflammatory related signalling mechanisms. As a feed supplement to mice on high-fat diet (HFD), WDS was shown to reduce the plasma concentration of the circulating markers of inflammation IL-1β and GM-CSF. The proteomic analysis of liver tissue from WDS-feed, HFD mice showed changes to STAT3 and the selenium associated proteins SEP15 and SecS. Prediction analysis based on protein expression indicated the down-regulation of inflammatory-related hepatic functions. Taken xvitogether, this thesis has revealed some of the mechanisms associated with the anti-inflammatory properties of WDS extracts in in vitroand in vivomodels.1 online resource (243 pages
Femtosecond laser-written integrated components for future all-fibre mid-infrared laser systems
No full textEmpirical thesis.Bibliography: pages 49-55.1. Introduction -- 2. Background on mid-Infrared fibre laser technology -- 3. Background on the femtosecond laser inscription process -- 4. Femtosecond laser inscription of fibre Bragg gratings for fibre laser applications -- 5. Integrated optical components -- 6. Conclusion -- References.Lasers emitting at mid-infrared (mid-IR) wavelengths in the 2.5-5 µm range are essential for various applications as this spectral region coincides with the vibrational-rotational absorption lines of many important atmospheric gases and liquid water. Fibre lasers are an efficient way to generate light at mid-IR wavelengths. However, mid-IR fibre laser technology is still in its infancy, mainly due to the non-existence of fibre coupled optical components to create all-fibre cavities, which severely limits their practical applications.This thesis investigates the feasibility of using a femtosecond laser to fabricate integrated components such as fibre Bragg gratings (FBGs), couplers and splitters which can add a new perspective for mid-IR all-fibre lasers. We report the development of a widely tunable (37 nm) all-fibre mid-IR laser based on a mechanically robust FBG which was inscribed through the polymer coating of a double clad fluoride fibre by focusing femtosecond laser pulses into the core of the fibre without the use of a phase mask. In a further step, the possibility of using on-chip optical couplers inscribed in fluoride and chalcogenide glasses is also investigated to pave the way for the realization of compact and robust mid-IR fibre laser systems for real-world applications in spectroscopy and medicine.Mode of access: World wide web1 online resource (xiv, 55 pages) diagrams, graphs, table
Migrants' settlement intentions in host cities in China
No full textTheoretical thesis.Bibliography included.Chapter 1. Introduction -- Chapter 2. Institutional legacy, citizenship and the changing settlement intentions of migrants in China -- Chapter 3. Employment status, labour market outcomes and settlement intentions of migrants in China -- Chapter 4. Breaking the barriers: how urban housing ownership has changed migrants' settlement intentions in China -- Chapter 5. Regional variations, social benefit entitlements and settlement intentions of migrants in China -- Chapter 6. ConclusionPatterns of human mobility and settlement are connected to the evolution of a society and the processes of urbanisation and industrialisation. Urbanization, rural-urban migration and settlement are important aspects in China's profound social change and economic reforms in recent decades. Due to its decades-long institutional constraints, the majority of rural-urban migrants prefer temporary migration or circular migration to permanent settlement if the household registration status is concerned. Research on China's internal migration to date have mainly focused on the role of institutional constraints on people's mobility and settlement. This thesis provides a new perspective in understanding migrants' settlement intentions and patterns, which is centred on migrants' settlement strategies in the context of economic transition and hukou reforms. The thesis examines how migrants intend to achieve permanent settlement by bypassing or overcoming hukou constraints. Based on the data from the 'Migrant Survey of Ningbo' conducted in 2014 and the 'Migrant Dynamics Monitoring Survey' conducted in 2013, this thesis found that the economic transition and hukou reforms provided migrants with opportunities to obtain full citizenship that is separated from their hukou status, which broadened the channels of achieving permanent settlement (Chapter 2). Particularly, the marketisation of the urban labour market improved migrants' socio-economic status and granted them with improved employment conditions, and therefore increasing the likelihood of their settling permanently and successfully via obtaining permanent residence, transferring their hukou status or owning local housing at the destination (Chapter 3). In addition, the urban housing market provided migrants with opportunities to achieve permanent settlement without having to transfer their hukou status. A new concept of 'de facto permanent settlement intention' was introduced to understand the diverse channels of permanent settlement based on the relaxed hukou constraints and the rise of urban housing market (Chapter 4). Further, regional differences in hukou premiums affected settlement intentions. Regions with high 'hukou premium' and quality social benefit entitlements were highly attractive to migrants, even though governments at all levels try to encourage migrants to permanently move to small- to -median cities (Chapter 5). The results of this study extend the application of migration theory in a society where profound social changes and rapid economic growth have been taking place in recent decades. The results provide a better understanding of migration and settlement decision making, which could inform policy formulation in the future.1 online resource (283 pages) illustration
Development of depression in behaviourally inhibited children: the role of risk-taking and reward-seeking in early adolescence
No full textThesis by publication.Includes bibliographical references.Chapter 1. General introduction -- Chapter 2. Risk-taking and inhibitory control in behaviourally inhibited and disinhibited preschool children -- Chapter 3. Behavioural inhibition in childhood and the development of adolescent depression : the role of puberty and risk-taking -- Chapter 4. The relationship between social risk-taking and depression in adolescence : the mediating effect of perceived social acceptance -- Chapter 5. Reward-seeking behaviour on an effort-reward task and symptoms of depression in early adolescents -- Chapter 6. General discussion -- References -- Appendices.Although depression rates increase rapidly in adolescence, the mechanisms behind this development are not fully understood. This thesis examined the role of several risk factors for adolescent depression with a focus on risk-taking, reward-seeking, early childhood temperament and social interactions. Two samples were used across four empirical papers. First, a sample of behaviourally inhibited (BI) and uninhibited (BUI) preschool children (n = 70). Second, a sample of adolescents initially recruited and classified at BI and BUI at age 4. Paper 1 examined how the temperamental constructs of BI and effortful control related to risk-taking. Effortful control, but not BI, at age 4 was related to reward focused risk-taking on the Balloon Analogue Risk Task (BART). Paper 2 examined the association between BI in childhood, risk-taking and depressive symptoms in adolescence, including how risk-taking as measured by the BART may present a potential risk pathway. An interaction between BI and risk-taking was associated with depressive symptoms in early adolescence. Due to the salience of peers in adolescence and the role that peer interactions might play in risk for adolescent depression, Paper 3 further explored risk-taking by developing a novel measure of social risk-taking and examining the association between scores on this measure and depressive symptoms over a 6-month period. A bidirectional relationship between social risk-taking and depressive symptoms was found. In addition, social acceptance partially mediated the relationship between depressive symptoms and social risk-taking. Finally, Paper 4 focused on reward-seeking using an adapted effort-reward task. No overall difference was found between early adolescents with or without symptoms of depression in their motivation to view a rewarding cartoon. Nevertheless, the task shows promise for future work in this area. Taken together, the results of this thesis present unique information about adolescent depression and the risk factors of temperament, risk-taking, reward-seeking and social risk takingMode of access: World wide web1 online resource (xiv, 214 pages) table
Low-frequency noise characterisation and modelling of metal-Oxide-semiconductor field-effect transistors
No full textTheoretical thesis.Bibliography: pages 59-62.1. Introduction -- 2. Noise mechanism -- 3. Noise characterisation -- 4. Device modelling and data verification -- 5. Conclusion and future workThe work presented here develops a systematic and self-consistent framework for the characterisation and modelling of low-frequency noise that is present in Silicon Metal-Oxide-Semiconductor Field-Effect Transistors (Si MOSFETs). The techniques and procedures developed in this work are general and can typically be applied to the low-frequency noise characterisation of any semiconductor device.In general, there are three topics presented in this work. First, a mathematical review of the mechanisms involved with the analysis of noise is presented.Furthermore, various types of intrinsic noise sources are mathematically reviewed.Second, an insight into the hardware associated with the characterisation oflow-frequency noise is given. Techniques and methods for validating the noise floor of a low-frequency noise measurement system are presented.Third, a systematic approach for validating the measured noise data is pre-sented by means of manually modelling the measured data. This is opposed to the use of software packages where automatic parameter extraction is typically performed.This work, in its entirety, is shown to hold for a given Si n-channel MOSFETdevice.1 online resource (xxii, 62 pages) illustration
The transition of an ESP teacher from a GE teacher: a case study
No full textTheoretical thesis.Bibliography: pages 57-60.Chapter 1. Introduction -- Chapter 2. Literature review -- Chapter 3. Methodology -- Chapter 4. Results -- Chapter 5. Discussion -- Chapter 6. Conclusion -- References -- Appendices.Previous studies have shown that many English for Specific Purposes (ESP) teachers are recruited from the ranks of General English (GE) teachers. However, no research has focused on the initial period of the evolution that these teachers experience. As part of an attempt to fill the gap in the literature, this Vietnamese case study explores and describes how a GE teacher has transitioned to become an ESP teacher. The study, thus, aims to provide in-depth insights into the teacher's beliefs and attitudes toward her new teaching field, her teaching practices, and the challenges she encounters. Multiple sources of evidence, including a biographic questionnaire, narrative frames, interviews, observations, and documents, are gathered from the Vietnamese English teacher and the research site for analysis. As the results reveal, the teacher regards ESP teaching as an interesting but challenging area. She performs three key duties, i.e.developing the coursebook, lecturing the course, and evaluating her students. She gives priority to the activities of vocabulary, reading comprehension, and translation in her teaching. In spite of her efforts, she faces several difficulties in her job such as the limited teaching time, limited content knowledge, poor cooperation with subject teachers, and an unsatisfactory syllabus. In presenting this teacher's experiences, this qualitative inquiry helps construct meanings of relevance for all novice ESP teachers who transfer from years of GE teaching - a common yet under-researched phenomenon.Mode of access: World wide web1 online resource (ii, 136 pages) diagrams, table
Physiology in anxious children and adolescents: a systematic review and empirical thesis
No full textEmpirical thesis.Bibliography: pages 35-59Introduction: A systematic review -- Methods -- Results -- DiscussionCognitive models of anxiety disorders, anxiety studies and diagnostic criteria highlight the role of physiology and somatic sensations in characterising and maintaining anxiety disorders. However, the bulk of research has focused on cognitive and behavioural components of anxiety disorders as targets for prevention and treatment programs, utilising adult samples. Studies indicate anxious adults demonstrate biased perception of somatic changes, and those individuals with anxiety exhibit abnormal physiological systems. It is unclear if these findings translate to children and adolescents with anxiety symptoms and disorders. We conducted a systematic review into the PsycINFO database, including the ancestry approach, and found 104 child and adolescent studies investigating physiology (hypothalamic-pituitary-adrenal axis and autonomic nervous system) at rest and/or reactivity to stress. The studies were largely heterogeneous, investigating healthy youths, youths with separation anxiety disorder, posttraumatic stress disorder, generalised anxiety disorder, social phobia, specific fears, high and low shy children, and high and low anxious children. Methodology varied greatly between studies; however, overall results indicate anxious youths demonstrate discordance or biased perception regarding their physical anxiety symptoms. There was some evidence that anxious youths have an elevated autonomic response to stress, and some evidence that they demonstrate a blunted physiological flexibility to stress, with less evidence that anxious youths have chronic hyperarousal. We discuss implications of the review's findings and future directions.1 online resource (ix, 138 pages
Chanting decreases stress and increases social connection
No full textEmpirical thesis.Bibliography: pages 39-48Chanting decreases stress and increases social connection -- Method -- Results -- Discussion.Chanting is an ancient practice recognised in many cultures and traditions all over the world. It is typically used as a meditation practice for healing and psychological growth. The goal of the current investigation was to determine whether 12 minutes of vocal and silent group chanting of the sound 'Om' would result in reduced physiological and psychological stress and increased feelings of social connection. It was hypothesised that both vocal and silent forms of chanting would decrease stress and increase feelings of social connection, however, it was predicted that the effects of vocal chanting should be more robust. Psychology students from Macquarie University (M = 21.79, SD = 7.17) were randomly allocated to one of two conditions: vocal or silent chanting. Prior and post chanting, participants completed the State Trait Anxiety Inventory, Adapted Self-Report Altruism Scale (including an additional 6 questions on cross-cultural altruism) and provided a saliva sample to assess cortisol levels. Following chanting, participants completed a manipulation check and provided a written description of their experiences of the chanting. Following both vocal and silent chanting, self-reported stress and cortisol levels significantly decreased. The reduction in cortisol was similar for vocal and silent chanting, but self-reported stress decreased significantly more following vocal chanting than silent chanting. As predicted, altruism increased following both vocal and silent chanting. Interestingly, however, there was no evidence that this benefit extended experiences of cross-cultural altruism. The findings are discussed in view of current theory and evidence on the physiological and psychological effects of chanting, singing and meditation.1 online resource (62 pages
Does neutral proportion modulate attentional control of task conflict in the Stroop task
No full textEmpirical thesis.At head of title page: Attentional control of task conflict.Bibliography: pages 41-44Abstract -- 1. Introduction -- 2. Experiment 1. -- 3. Experient 2. -- 4. Comparison of Experiment 1 & 2 -- 5, Genreal discussion -- 6. ReferencesThe Stroop interference effect is finding that it takes longer to name the colour that a word is displayed in when the word spells the name of an incongruent colour(e.g. the word RED display in blue), relative to when the word is displayed using a non-linguistic string(e.g. XXXX displayed in blue). The Stroop interference effect is commonly thought to reflect an informational conflict between the information that is supplied by the word dimension of the stimulus and the information supplied by display colour dimension of the stimulus. However, more recently, it has been proposed that the Stroop interference effect may also be due to a task conflict(Goldfarb & Henik, 2007). Task conflict refers to competition between task-sets, which are the sets of cognitive processes used to perform specific tasks. A word displayed in colour is associated with two task sets: reading and colour naming. Stroop interference occurs when the word dimension of the Stroop stimulus automatically triggers the task set of reading, which then conflicts with the task set of colour naming(Monsell, Taylor & Murphy, 2001).However, the automaticity of reading has been called into question by the finding that the Stroop interference effect can be modulated, which has been taken as evidence that the task of reading can be controlled using attention. Specifically, Goldfarb and Henik (2007) have shown that the Stroop interference effect is magnified when there is a high proportion of non-linguistic neutral trials (e.g., a row of Xs), and argued that this is because when people do not experience conflict, attentional control over the task of reading is relaxed, and they open themselves up to the interfering effects of word distractors.The present thesis examined whether the task conflict is modulated by attentional control by examining the effect of neutral trial proportion on colour-unrelated word distractors (e.g. ABBEY or CHART). Previous research by Kinoshita, De Wit and Norris ATTENTIONAL CONTROL OF TASK CONFLICT v(2017) found that colour unrelated words interfered with colour naming, but this interference was absent when the response to the colour was manual, in what would amount to a low neutral proportion condition. In the present thesis, the word interference effect was magnified when there was a high proportion of neutral trials, in both the vocal and manual Stroop tasks.Using both an analysis of RT distribution and the effect of previous trial type (the "Gratton effect"), I examined the mechanism of attentional control of task conflict.RT distribution analysis showed that the magnification of the word-interference effect in the high neutral proportion condition was constant across the RT bins in the manual task and increased in size across the RT bins of the vocal task.Previous trial type modulated the size of the word interference only in the vocal task, and only in the low neutral proportion condition.Taken together, it is suggested that increasing the proportion of neutral trials relaxes attentional control of the task set of reading and that the reactive form of control operatesonly when a high level of conflict isexperienced.1 online resource (59 pages