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The public as plural. Popular economy and agroecological workplaces in Argentina (2015-2023)
Get PDFAcross Latin America, diverse local actors engage in the defence and creation of public initiatives against processes of extractivism, privatisation, and dispossession. Emerging as alternatives to the hegemony of agribusiness, and revitalising labour organisations, in Argentina, popular economy and agroecological movements are reimagining the public. On formerly disused public lands, they create workplaces to progress towards social inclusion and environmental regeneration.
In this thesis, I show how their practices express a distinct form of publicness. I argue that publicness can be understood in three interconnected ways. First, it takes a plural form. Through collaboration among different groups of participants at the local level, a mosaic of various actors contributes to the construction of popular economy and agroecological initiatives. This plural mosaic can include the participation of state agencies. However, these initiatives transcend a state-centred form of publicness, since they depend on the commitment of popular economy workers alongside various environmental activists. Second, at the heart of this plural form of publicness is a specific type of participant subjectivity: that of the worker and producer. The centrality of workers underpins the popular and agroecological form of publicness. Third, this publicness involves the active transformation of concrete spatialities, places that are reimagined and reconstructed by participants to become productive. In these sites, economic production is oriented towards encompassing socio-environmental aims.
A qualitative study examining two cases from the provinces of Entre Ríos and Buenos Aires enables me to construct concepts grounded in the experiences of two significant agroecological and popular economy movements in Argentina: the UTT and the UTEP. The cases also allow to identify the differences in local government support for the initiatives. My findings are rooted in the socio-political context of Argentina post-2015, characterised by increasing social mobilisation of popular sectors. My analysis provides situated conceptualisations and analytical insights to support research on the emerging forms of participatory publicness in the 21st century
Effects of empagliflozin on fluid overload, weight and blood pressure in chronic kidney disease
Get PDFBackground:
Chronic kidney disease (CKD) is common worldwide and associated with considerable morbidity and mortality, largely due to cardiovascular disease. As CKD progresses, fluid overload is a common manifestation which has both clinical and prognostic implications. Bioimpedance spectroscopy is commonly used in the dialysis setting to assess fluid status but less so in earlier stages of CKD.
Sodium-glucose cotransporter 2 (SGLT2) inhibitors have recently been shown to slow the progression of kidney disease and additionally have cardiovascular benefits. The underlying mechanisms of SGLT2 inhibitors remain incompletely understood but include diuretic effects and so they may reduce fluid overload. Trial reports demonstrate consistent treatment effects across a range of patient subgroups however these don’t address the real-life scenario in which the highest risk patients (such as those with frailty) exhibit several characteristics in combination. Clinicians may hesitate to prescribe SGLT2 inhibitors in patients with frailty (which is common in CKD) due to perceived altered risk-benefit profile.
The hypothesis of this work is that the beneficial effects of empagliflozin (an SGLT2 inhibitor) on kidney and cardiovascular outcomes in CKD may be in part explained by fluid reduction which can be assessed using bioimpedance spectroscopy. This work will explore potential contributory mechanisms (through effects on fluid overload and blood pressure) and whether there is heterogeneity of treatment effect (focusing on frailty).
Methods:
A systematic review was conducted to inform the analysis strategy for analyses of the effects of empagliflozin on fluid overload. The full methods of the EMPA-KIDNEY trial have been reported elsewhere. In brief, 6609 patients with CKD at risk of progression with an estimated glomerular filtration rate (eGFR) ≥20 and <90 mL/min/1.73m2 were randomised to either empagliflozin or matching placebo. The primary outcome was the first occurrence of kidney disease progression or death from cardiovascular causes. An EMPA-KIDNEY bioimpedance substudy obtained bioimpedance measurements in addition to routine trial procedures at the randomisation, 2- and 18-month follow-up visits in 660 participants. Weight and blood pressure were measured at all visits. “Risk of hospitalisation during follow-up” at baseline was used as the primary frailty indicator with supplementary analyses by multimorbidity, polypharmacy and health-related quality of life at baseline.
Effects of empagliflozin on fluid status, blood pressure and weight were assessed using a mixed model repeated measures (MMRM) approach; and effects on binary endpoints were assessed using Cox regression models; with adjustment for age, sex, prior diabetes, eGFR, and urinary albumin-to-creatinine ratio (uACR) in the categories used in the minimised randomisation algorithm. Pre-specified subgroups were categories of sex, diabetes, eGFR and N-terminal pro B-type natriuretic peptide (NT-proBNP) and subgroup-specific treatment effects were estimated by fitting interaction terms in the MMRM or Cox models and calculating heterogeneity or trend statistics. Frailty (predicted risk of hospitalisation) was determined by logistic regression models with recorded hospitalisation (first event) as the response variable. All variables which were significantly associated (P<0.01) with hospitalisation in univariable models proceeded to inclusion in multivariable model building using forward stepwise selection and likelihood ratio tests with significance threshold P<0.01. Frailty subgroups were defined according to predicted risk of hospitalisation and relative and estimated absolute effects on the trial’s primary outcome and all-cause hospitalisation were assessed.
Results:
In 620 substudy participants included in the primary assessment, compared to placebo, the study-average absolute difference in absolute “Fluid Overload” was -0.24 L (95% CI -0.38, -0.11). Effects were similar at 2- and 18-months (-0.23 [-0.37, -0.08] and -0.26 [-0.46, -0.06] L, respectively; P value for interaction with time = 0.11) and across the pre-specified subgroups. There were no significant between-group differences in bioimpedance-derived fat or lean tissue parameters. In the bioimpedance substudy cohort, the study-average between-group difference in total body weight in kg was -0.7 kg (95% CI -1.3, -0.1), consistent with the -0.9 kg (95% CI -1.2, -0.6) difference observed in the full trial cohort. In the full trial, the effects on weight persisted over time (P for interaction = 0.47) with consistent effects across subgroups. The study-average between-group differences in systolic and diastolic blood pressure in the full trial cohort were -2.6 mmHg (95% CI -3.3, -1.9) and -0.5 mmHg (95% CI -0.9, -0.1), respectively with similar results in the substudy cohort. There was no evidence of heterogeneity of the blood pressure lowering effect of empagliflozin when subdivided by sex, baseline eGFR or NT-proBNP but there was some evidence to suggest greater systolic blood pressure lowering in patients with diabetes (-4.1 [0.3] versus -1.9 [0.3] mmHg; heterogeneity P value = 0.001).
Overall, compared to placebo, empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death by 28% (HR 0.72, 95% CI 0.64-0.82), with no significant difference in relative effects by baseline frailty (P for heterogeneity all >0.05). In absolute terms, there was evidence of larger estimated benefits on the primary outcome in participants in the highest category of frailty (based on risk of hospitalisation) compared to those with lesser degrees of frailty: per 1000 participants treated, empagliflozin was estimated to result in 38 fewer primary outcomes among those in the highest frailty category compared to 14 primary outcomes avoided annually in the lowest third of frailty. Safety outcomes such as dehydration and bone fractures were more common in participants with indicators of increased frailty, but there was no significant effect of study treatment on any of these outcomes overall or among those who were most frail.
Conclusion:
The findings from this thesis demonstrate that the benefits of SGLT2 inhibitor treatment extend beyond the main effects on slowing kidney disease progression and provide some mechanistic insights into how these benefits are mediated. Empagliflozin resulted in sustained reductions in “Fluid Overload”, weight and blood pressure in patients with CKD with and without diabetes with no demonstrable effect on fat mass. This effect was evident even in patients with low levels of kidney function. In the studied population, the absolute benefits of empagliflozin on the primary outcome (kidney disease progression or cardiovascular death) were greater in patients with the highest levels of frailty and outweighed the absolute risks of adverse events
Intensification of catalytic process in premixed lean hydrogen/air combustion
Get PDFThe global energy use is moving towards hydrogen energy to make the energy sector clean, efficient and sustainable. Therefore, ambitious policies globally on hydrogen energy are made and aimed at transitioning away from fossil fuels to meet the goals of climate change through the Paris Climate Agreement. For this, moving to hydrogen fuel use is a feasible and promising solution, especially, to replacing the fossil fuel use in combustion systems. As NOx emissions pose a major challenge, further innovation and research are crucial for developing low/ultra-low NOx hydrogen combustion systems. In this regard, catalytic aided combustion widely investigated in the literature, is useful for efficient hydrogen combustion with reducing significant NOx emission at low temperatures. However, given the limitations of noble metal use and its high cost, fundamental research is required to optimise the catalytic reactor design with minimal use of expensive catalysts.
The present study begins by numerically investigating the premixed combustion of H2/air over a platinum catalyst in a planar monolithic reactor (a block with parallel channels resembling a honeycomb structure), with the goal of stabilising the flame under lean to ultra-lean conditions. A steady laminar species transport model is initially used, incorporating elementary heterogeneous and homogeneous chemical reaction schemes, and the results are validated against experimental data. A stability map for the equivalence ratios (φ) of 0.15 to 0.20 is obtained from a non-catalytic burner, forming the basis for the catalytic flame analysis. In the non-catalytic burner, no flame is observed for φ ≤ 0.16, and flame extinction occurs at a Reynolds number (Re) below 571 for φ = 0.18 and below 381 for φ = 0.20. Additionally, a significant amount of unburned hydrogen exits the reactor in all cases. However, with a Pt catalyst coated on the walls, complete H2 combustion is achieved for 0.10 ≤ φ ≤ 0.20, with gas-phase (homogeneous) reactions becoming more prominent at higher Re. In addition, the superadiabatic temperatures are observed close to reactor walls in all studies cases. Moreover, wall radiation and inlet conditions influence combustion kinetics and flame temperature. Under the same conditions, NOx emissions increase with equivalence ratio but are negligibly affected by the inflow Reynolds number.
Given the high cost and scarcity of noble metal catalysts, this study also focuses on a numerical investigation to determine the best way of coating a platinum catalyst inside a catalytic hydrogen reactor. Various planar and non-planar reactor configurations are examined, and the results show that a reactor combining half and full cylinders is the most effective in achieving better H2 conversion. Compared to an equivalent planar catalytic reactor, this non-planar configuration improves H2 conversion by 30.7%. The findings suggest that enhancing mass and heat convection significantly boosts H2 conversion. Moreover, the contours of flow parameters and temperatures reveal that cylinders inside the reactor significantly affect the flow near the catalytic surfaces and have benefits in reducing the intensity of super adiabatic temperatures. Additionally, non-planar reactors, with surfaces of improved mass and heat transfer, can achieve up to 50% catalyst savings while maintaining a conversion rate of 2 kg/s per unit of catalytically-coated surface area.
To simulate a realistic catalytic process, Large Eddy Simulations (LES) have been conducted. This represents the first attempt at LES modelling for catalytic monolith reactors to predict catalytic reacting flows. A premixed hydrogen/air mixture at a fuel-lean equivalence ratio of 0.15 and an incoming Reynolds number of 3500 is used for analysis. Both planar and non-planar reactors are studied and compared under the same conditions and with the same platinum-coated surface area. The simulations employed a turbulent kinetic energy sub-grid model and the eddy dissipation concept to model the turbulent catalytic reacting flow. A discrete ordinate model is used to account for radiation heat transfer. The LES results, validated against experimental data, demonstrate that placing cylinders along the reactor enhances convective mass transfer, intensifies catalytic combustion, and enables efficient combustion with less catalytic surface area. Compared to planar models, non-planar reactors exhibited significantly higher H2 conversion efficiency along the reactor length, allowing for a catalyst savings of nearly 62.5%.
Finally, an experiment was conducted in a catalyst-packed bed tubular reactor to investigate the effect of varying catalyst content (0.3%, 0.5%, or 1.0% Pt in Al₂O₃ pellets and 0.5%, or 5.0% Pd in Al₂O₃ pellets) and catalyst loading (1.0 g, 2.5 g, and 5.0 g). The choice of experimental approach in a packed bed reactor is due to limitations of addressing the effect of catalyst material and amount of catalyst loading in numerical modelling. Measurements were taken in the packed bed reactor across the flow rates ranging from 1 LPM to 5 LPM. The results show that the packed bed with higher Pt/Pd content generates elevated combustion temperatures and demonstrates an effective catalytic performance. Moreover, the pellets with Pt/Pd content, even with a loading of 1 g at low flow rates, exhibit catalytic performance comparable to higher catalyst loadings at different flow conditions
Comparison of centralized and decentralized municipal plastic waste management producing value-added resources: economics, environmental impacts and optimisation
Get PDFPlastic waste is a global issue that severely threatens the environment if not managed properly. Municipal plastic waste is widely treated in unsustainable ways such as landfill and incineration that generally do not contribute to the circular economy or to the principles of the UN’s sustainable development goals (SDGs). Mechanical recycling is not able to handle all municipal plastic waste generated due the technological limitations. Chemical recycling, specifically pyrolysis, is considered an alternative solution or supplementary to mechanical recycling because of its potential to recover fuels and chemicals from non-recycled municipal plastic waste.
In this study, large-scale centralized and small-scale decentralized diesel and hydrogen production from NMPW (non-recycled municipal plastic waste) using pyrolysis-based thermochemical conversion technologies were compared in terms of environmental footprint and economic feasibility, specifically focusing on GWP (Global Warming Potential) and NPV (Net Present Value). Glasgow was chosen as the case city for this study. LCA (Life Cycle Assessment) was applied to evaluate the GWP of all systems. The results showed that centralized systems had lower GWP compared to decentralized systems, despite their greater transportation distances. The GWPs of diesel production for centralized and decentralized systems were 801 and 1,345 kg CO₂-eq per tonne of NMPW, respectively. Hydrogen production, however, had much higher GWPs of 7,110 and 7,990 kg CO₂-eq per tonne of NMPW for centralized and decentralized systems, respectively. The end use of diesel produced has a greater carbon footprint than the end use of hydrogen. The carbon saving from the displacement of fossil hydrogen was two times higher than that from diesel displacement. After considering the end use of products and displacement, the net GWP of large-scale hydrogen production is 2,496.53 kg CO₂-eq per tonne of NMPW, which is better than the net GWP of small-scale diesel production (2,766.3 kg CO₂-eq per tonne of NMPW) and close to the net GWP of large-scale diesel production (2,114.44 kg CO₂-eq per tonne of NMPW).
After completing the assessment of the environmental footprint, in Cost-Benefit Analysis (CBA), the economic feasibility of centralized large-scale and decentralized smallscale diesel and hydrogen production systems from NMPW was compared by defining their NPVs. Across all scenarios, only centralized large-scale diesel production, with and without carbon capture and storage, exhibited total positive net present values (£22,240,135 and £24,449,631, respectively), indicating their economic feasibility. The decentralized small-scale hydrogen production system with carbon capture and storage yielded the lowest net present value result (-£2391) per tonne of treated non-recycled municipal plastic waste. Particularly, the production of diesel and hydrogen from non-recycled municipal plastic systems, with carbon dioxide emissions to the environment, demonstrated better economic performance than the same systems capturing and storing carbon dioxide, attributable to its higher capital and operational expenditures. Also, sensitivity analysis revealed that the fuel sales price and OPEX had the most significant impact on the net present values.
In the MOO (Multi-Objective Optimization) study, 900 diesel and hydrogen-producing scenarios from NMPW were developed, and the data thus generated was then used for inventory analysis to calculate their GWPs and NPVs. After that, the long short-term memory recurrent neural network was applied to define temporal dependencies and dynamics of systems, which was integrated with Monte Carlo simulations of variables to expand scenarios from 900 to 700,000 and to predict their GWPs and NPVs. Finally, a Pareto front was derived from the GWPs and NPVs, from which the best scenarios in terms of balance between environmental and economic performance was identified using the TOPSIS and LINMAP approaches. The TOPSIS approach defined a scenario that aligns perfectly with the ideal scenario, achieving the lowest GWP (-2570.42 kg CO₂-eq. per tonne of NMPW) and the highest NPV (£300,315.65 per tonne of NMPW). This demonstrates that the TOPSIS method effectively balances environmental and economic performance of NMPW management system. In contrast, the LINMAP approach obtained a less optimal scenario, with a moderate GWP reduction (-1025.28 kg CO₂-eq. per tonne of NMPW) and a negative NPV (-£1,402.92 per tonne of NMPW). This means that the TOPSIS approach is recommended for selecting optimal scenarios, as it provides the best balance between environmental and economic performance for NMPW management systems utilizing pyrolysis-based thermochemical conversion technologies.
Based on the LCA, CBA, and MOO studies, several recommendations were developed for practical applications, and a few of them are worth highlighting. Currently, among the scenarios considered in this study, only diesel production from NMPW in a large-scale plant is economically feasible and can achieve a negative GWP if a CCS unit is applied. Additionally, pyrolysis plants should be located close to feedstock collection sources to reduce transportation costs and minimize environmental impact. When selecting between large-scale NMPW systems and small-scale systems utilizing pyrolysis-based thermochemical conversion processes, the large-scale option is recommended due to its superior environmental and economic performance
Exploring adults’ experiences of treatment for Tourette syndrome and tic disorders
Get PDFAbstract available at each chapter
Race, gender, maximalism: counter-portraits of the U.S. in the contemporary “big” American novel
No full textAbstract not currently available
Three dimensional light fields in atomic state interferometry
Get PDFThis thesis is about the interaction of structured light with atoms in the presence of external magnetic fields. Both light and atoms can carry phase dependent structures, the expression of which often depends on the choice of quantisation axis. The most general type of spatial structure light can have manifests as polarisation patterns. This type of structure is quantified as the optical concurrence. Although polarisations are usually considered to be two-dimensional, light can also carry a longitudinal polarisation component, but it has not been directly measured before.
Atomic states can be altered by external electric and magnetic fields. These fields don’t just alter the atom’s charge density distribution, but the very state space that defines it. Additionally, it is possible to redefine atomic states as superpositions of one another in order to reveal hidden structures. Previously, the best theoretical models of structured light-matter interaction were only valid for special cases, but a generalised model can open new opportunities for describing, understanding, and ultimately measuring ambient electric and magnetic fields.
In this thesis, the energy shifts induced in atoms by strong magnetic fields have been utilised to visualise an atomic transition normally unavailable in the chosen configuration being driven by longitudinal light. At the same time, a generalised model of the atomic state interferometer is constructed, and shown to be capable of predicting new ways to measure magnetic fields and optical concurrence.
The atomic state interferometer requires only a single transmission image for these measurements, and its validity means that it is possible to look for other combinations of electric and magnetic fields that can reveal further symmetries within the atom. In addition to having a highly versatile and customisable device that can measure the interplay of electric and magnetic fields, this thesis demonstrates a spatially resolved way of investigating three-dimensional polarisation states.
Having unlocked access to a new type of polarisation, the next steps are to investigate properties of strongly focused beams that have previously been confined to the realm of theory. On the more practical side, the atomic state interferometer lends itself to sensing applications, such as the measurement of non-classical correlations between degrees of freedom in a beam. Currently, work is being done to build a miniaturised research magnetometer based on the same principles.
In short, atoms provide a good interface between classical and quantum world. Customising their available state space opens the way to a new generation of sensors
Investigating the associations between plasmodium infections and autoimmunity in sub-Saharan Africa
Get PDFAutoimmune diseases affect 5- 8% of the global population and are known to occur due to a misguided immune response towards the host, consequently affecting several organs. Importantly, infections are considered key environmental triggers of autoimmunity and contribute to the onset of autoimmune diseases, though this idea remains controversial. In this research, I focus on malaria, a disease caused by Plasmodium species, which has been linked to autoimmunity through the induction of anti-self-antibodies, with higher levels of autoantibodies associated with disease severity. By contrast, there is evidence suggesting that autoantibodies play a crucial role in anti-malarial protection, with increased autoantibodies shown to inhibit parasite growth. Thus, autoantibodies play a dual role in protection and pathology. However, this raises a crucial question on whether the induction of autoimmune antibodies during malaria increases predisposition to autoimmune disease later in life.
Herein, anti-citrullinated protein autoantibodies (ACPA) commonly associated with clinical diagnosis of rheumatoid arthritis and their corresponding native peptides were first screened using ELISA in mice infected with the model pathogen Plasmodium chabaudi. This approach was chosen to investigate whether Plasmodium triggers ACPA production, providing insights into the potential link between Plasmodium infections and autoimmunity. Subsequently, the impact of heightened antibody responses to both the native and citrullinated peptides on the development of a model of experimental arthritis in mice was assessed. Extending the findings to humans, serum samples obtained from individuals residing in areas with varying levels of malaria exposure were examined for the presence of autoimmune markers using ELISA and protein microarray assays. This was followed by assessing differential cellular immune phenotypes using flow cytometry.
Interestingly, increased levels of antibody responses to both the native and citrullinated peptides were observed in the P. chabaudi-infected mice with levels comparable to those observed in a chronic experimental arthritis model. However, despite the elevated autoantibodies, under the experimental conditions used in our study, infection-induced autoantibodies did not appear to influence the outcome of either acute or chronic experimental arthritis in mice.
Furthermore, expanding our findings to adults and children residing in malariaendemic areas, I observed that individuals living in high malaria transmission areas exhibited elevated antibody responses to both the native and citrullinated peptides compared to those in low transmission areas. Interestingly, a similar trend was observed in children, particularly children with uncomplicated and severe malaria who had increased levels of autoantibodies compared to healthy children. In addition, protein microarray data suggested that individuals from a high malaria transmission area had an overall increase in autoimmune reactivity. Notably, higher levels of antibodies against both the native and citrullinated peptides were also associated with increased frequency of atypical B cells (CD27⁻ CD21⁻CD11c⁺T-bet⁺) and a reduction in the levels of FOXP3 regulatory T cells.
My research indicates that Plasmodium infection leads to a broad spectrum of autoantibodies, including responses to both the native and citrullinated peptides as well as extracellular antigens, mirroring a profile of increased autoantibodies typically observed in autoimmune diseases. Moreover, in this study, I report the presence of elevated antibody responses to these peptides in both Plasmodium infected mice and humans residing in areas of high Plasmodium falciparum transmission. Notably, the pre-existing autoantibody response to these peptides from a single Plasmodium infection episode did not modulate susceptibility to experimental autoimmune arthritis. Thus, the effect and role of chronic exposures to P. falciparum infections on the risk of developing autoimmune diseases in people living in endemic areas cannot be ruled out and should be determined
A comparative analysis of translated plays in the Chinese theatre of the post-cultural revolution period
Get PDFThis dissertation examined the influence of socio-political and cultural factors on the translation of Chinese theatre, with a focus on avant-garde works from late 1970 to 2000. This study is organized into three time periods: late 1970 to 1988, 1989 to 1992, and 1993 to 2000, analysing three representative translated Chinese avant-garde theatrical works within each period through the lens of theatre translation, considering the socio-political and cultural contexts of the time and the requirements of text users.
The dissertation comprises six chapters. Chapter 1 provides historical background, outlining the development of Chinese theatre and the emergence of avant-garde theatre from the late 1970s, establishing the research context. Chapters 2 a theoretical framework, methodologies used in analysing three translated playscripts. The theoretical framework mainly introduces the cultural turn in terms of Andre Lefevere's poetics and ideology theories, translation concepts of Hans J. Vermeer’s Skopos theory together with Lawrence Venuti’s domestication and foreignisation, emphasising the impact of cultural, social, and text-user factors on theatre translation. Chapter 3, Chapter 4 and Chapter 5 are textual analyses of three selected Chinese avantgarde works which are Death of a Salesman (1983), Hamlet 1990 (1990) and Three Sisters Waiting for Godot (1998) which are translated and adapted from foreign theatrical works. These three chapters investigate translation decisions and their associated influential factors concerning language, theme, and play structure, drawing on theatre translation theories. Finally, the concluding chapter summarises the general trends in Chinese avant-garde theatre translations from 1980 to 2000. Using the three case studies, this study highlights how translations are influenced by varying sociocultural- political factors to meet the requirements of the target culture and text users
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