Phenotypic and Molecular Characterisation of Silicon Uptake and Deposition in Festuca arundinacea

Silicon (Si) is taken up from the soil as monosilicilic acid by plant roots, transported to leaves and deposited as phytoliths, amorphous silica (SiO2) bodies, which are a key component of anti-herbivore defense in grasses. Silicon transporters have been identified in important crop species such as rice and barley, but the mechanisms behind the transport of Si remain poorly characterised in many non-crop grasses. Specifically, the extent to which Si uptake and deposition is driven by Si transporter expression remains disputed. Induction of Si defenses in response to herbivory suggests plants exhibit control over Si uptake and distribution. This thesis investigated the effects of wounding and Si addition on foliar Si concentration and deposition, and on Si transporter gene expression, in different genotypes of the economically important forage grass Festuca arundinacea, which exhibits variation in Si uptake and deposition. Following Si addition and damage, varieties differed in Si concentration, the numbers of leaf spines, and in the magnitude of the increase in Si uptake induced by damage. Some previous studies suggest trade-offs may exist between Si and carbon, but thus far such potential trade-offs have not been investigated intra-specifically, nor have there been any tests of the existence of trade-offs between different types of Si-based defenses. Trade-offs between leaf spines and phytoliths, and between Si and the key structural component, lignin, were found. This thesis presents novel findings on how Si defenses are mobilised in response to damage, how they are regulated at the level of gene expression, and how Si is deposited in different structures on the leaf surface and within cells. These findings have implications for improved understanding of plant defense and for the targeted selection of traits during breeding for sustainable crop protection

Evidence for Active Uptake and Deposition of Si-based defenses in Tall Fescue

Silicon (Si) is taken up from the soil as monosilicic acid by plant roots, transported to leaves and deposited as phytoliths, amorphous silica (SiO2) bodies, which are a key component of anti-herbivore defense in grasses. Silicon transporters have been identified in many plant species, but the mechanisms underpinning Si transport remain poorly understood. Specifically, the extent to which Si uptake is a passive process, driven primarily by transpiration, or has both passive and active components remains disputed. Increases in foliar Si concentration following herbivory suggest plants may exercise some control over Si uptake and distribution. In order to investigate passive and active controls on Si accumulation, we examined both genetic and environmental influences on Si accumulation in the forage grass Festuca arundinacea. We studied three F. arundinacea varieties that differ in the levels of Si they accumulate. Varieties not only differed in Si concentration, but also in increases in Si accumulation in response to leaf damage. The varietal differences in Si concentration generally reflected differences in stomatal density and stomatal conductance, suggesting passive, transpiration-mediated mechanisms underpin these differences. Bagging plants after damage was employed to minimize differences in stomatal conductance between varieties and in response to damage. This treatment eliminated constitutive differences in leaf Si levels, but did not impair the damage-induced increases in Si uptake: damaged, bagged plants still had more leaf Si than undamaged, bagged plants in all three varieties. Preliminary differential gene expression analysis revealed that the active Si transporter Lsi2 was highly expressed in damaged unbagged plants compared with undamaged unbagged plants, suggesting damage-induced Si defenses are regulated at gene level. Our findings suggest that although differences in transpiration may be partially responsible for varietal differences in Si uptake, they cannot explain damage-induced increases in Si uptake and deposition, suggesting that wounding causes changes in Si uptake, distribution and deposition that likely involve active processes and changes in gene expression. Introductio

Early reconstitution of effector memory CD4+ CMV-specific T cells protects against CMV reactivation following allogeneic SCT.

Reactivation of CMV is a common complication following allogeneic haematopoietic SCT and is associated with significant morbidity and mortality. The relative importance of the CD4+ and CD8+ components of the CMV-specific immune response in protection from reactivation is unclear. The CMV-specific CD4+ and CD8+ immune response was measured at serial time points in 32 patients following allogeneic HSCT. Intracellular cytokine staining following CMV lysate stimulation and HLA-peptide tetramers were used to determine CMV-specific CD4+ and CD8+ responses, respectively. A deficient CMV-specific CD4+ T-cell immune response within the first 30-50 days post transplant was associated with high risk of viral reactivation. Patients with combined impairment of the CD4+ and CD8+ immune response within the first 100 days were susceptible to late viral reactivation. The frequency of CMV-specific CD4+ T cells correlated with CMV-specific CD8+ T cells, comprising 10% of the whole T-cell repertoire. Early CMV-specific CD4+ T-cell reconstitution was dominated by effector memory cells with normal levels of IL-2 resuming 6 months following transplantation. In summary, both CD4 and CD8 CMV-specific immune reconstitution is required for protection from recurrent activation. Measurement of the magnitude of the CMV-specific CD4+ immune response is useful in managing viral reactivation following HSCT

Expanding the Just Transition to Include Teachers: Composting, Zero Waste and Climate Action in Montreal Schools

In the context of the current climate emergency, governments are implementing important climate policies promoting zero waste, carbon neutrality, increased greening, and protection of biodiversity. While climate policies are created with the best of intentions, they obscure the lived experiences of front-line workers attempting to implement these policies in a rapidly changing environment. This article proposes a nuanced understanding of a “just transition” as a promising proposal for climate justice and labour politics. Through drawing on institutional ethnographic approaches to conducting interviews, gathering fieldnotes during observations, and conducting textual analysis, this article connects educational workers’ experiential knowledge with climate policies that shape educational possibilities both locally and extra-locally. By interrogating the enactment of recent zero waste policy from the perspectives of teachers, a principal, and a school board employee, the research findings and discussion increase understanding of how climate change mitigation efforts and policies can produce unequal and unintended effects.Dans le contexte de l’urgence climatique actuelle, les gouvernements mettent en œuvre d’importantes politiques climatiques portant sur le zéro déchet, la neutralité carbone, l’augmentation des espaces verts et la protection de la biodiversité. Bien que ces politiques soient élaborées avec les meilleures intentions, elles occultent les expériences vécues des travailleurs de première ligne qui tentent de les appliquer dans un environnement en mutation rapide. Cet article propose une compréhension nuancée de la « transition juste » comme une piste prometteuse pour la justice climatique et les politiques du travail. En s’appuyant sur des approches ethnographiques institutionnelles pour mener des entretiens, collecter des notes d’observation sur le terrain et analyser les transcriptions, cet article relie les savoirs expérientiels des acteurs éducatifs aux politiques environnementales qui influencent les possibilités éducatives à la fois localement et au-delà. En examinant la mise en œuvre récente d’une politique zéro déchet du point de vue des enseignants, d’un directeur d’école et d’un employé d’une commission scolaire, les résultats de cette recherche et la discussion autour de celle-ci permettent de mieux comprendre les effets inattendus et inégalitaires que peuvent générer les initiatives et les politiques en faveur de l’atténuation du changement climatique

Production of a hands-on learning resource to teach the topic of loci at GCSE

The origin of this study is rooted in an interest to design an innovative resource to teach the GCSE Mathematics topic of Loci in a more engaging and contextualised way. The aim of the resource is to provide pupils, of differing learning styles, with the opportunity to learn Mathematics through a range of mediums, particularly through hands-on and contextualised learning. The effectiveness of producing a hands-on learning resource to teach the GCSE topic of Loci is the main research question considered in this study.  The planning, design and creation of the resource consisted of two key elements; a set of five hands-on learning boards, each relating to the five specific concepts of Loci, and a Prezi Presentation, ‘5 Loci in Locustown’ which will guide both pupils and teachers around the tasks. This resource is also accompanied by a teacher-guide, acetate overlays and counters. The resource was trialled with two experienced GCSE Mathematics teachers, four undergraduate Mathematics teachers and two GCSE Mathematics pupils. Qualitative and quantitative data, was collected for research purposes through the conduction of semi-structured interviews and completion of web-based questionnaires. The results in the interviews and questionnaires highlighted that the resource was very successful in engaging students in the topic of Loci through the implementation of hands-on learning and ICT. However, some respondents commented that perhaps more time could have been spent trialling the product and developing it further to ensure a deeper understanding of the hidden Mathematics.  The research project provided the opportunity to be creative in designing an innovative resource to teach the GCSE topic, Constructing Simple Loci. Like many other Mathematical topics, Loci can be exciting when incorporating hands-on learning and ICT and made relevant to pupils when problems are contextualised. This way of teaching avoids isolation within learning and ensures that a pupil’s learning in Mathematics is linked to their real-life experiences.   Based on these key findings and taking account of the strengths and limitations of this research, the project could be further developed to ensure there is full understanding of the underlying Mathematics. More research needs to be invested into how pupils of all abilities and learning styles can benefit from using manipulatives in the classroom and relating Mathematics to real life situations

One and I : Dimensions of Ritual Unity and Individuality in the Liturgical Practice of the Catholic Nicene Creed

Catholicism is a global religion with members who come from a diverse array of countries and sociocultural backgrounds, yet the Catholic Church and its members throughout the world value a shared set of traditional practices. This complex relationship between collective orthodoxy and personal variation among Catholics is particularly visible in the liturgical ritual of the Nicene Creed, a statement of faith that is professed as part of every Sunday Mass. Based upon contextual cases from the Lewiston Prince of Peace Catholic Parish, I argue that when the Nicene Creed is performed, elements of unity and individuality coexist and contribute to a Catholic community whose members value the same traditions in different ways. This thesis utilizes scholarly theory on ritual performance, ethnographic observations from my participation in church services, and interviews with local Catholics to analyze the complex dimensions of liturgical engagement with the Creed. My study stresses the importance of recognizing how individualized signification complicates institutionalized unification. Differences in identity, experience, and interpretation allow for diversity within even the most orthodox religious practices, such as the Nicene Creed. These insights may inform other studies of religious traditions, especially those in Catholicism. Additionally, I address my position as a scholar-believer analyzing my own faith: being both a Catholic and a student situates me with intersecting identities in this study, and this stance relates to ongoing academic discussion of ethnographic ethics and practices

Nitrogen oxide decomposition by barrier discharge

Nitrogen oxides have been linked to numerous air pollution problems including the production of ozone in the troposphere and acid rain. Annual nitrogen oxides emissions in the United States exceed 21 million tons and are primarily a result of the high temperature combustion of fossil fuel. Recent regulations in the U.S., both federal and state, require that nitrogen oxides emissions be reduced over the next several years. Control of nitrogen oxide emissions is difficult in combustion exhaust gases because of their low concentration and reactivity. Numerous technologies have been developed to reduce emissions but the costs are generally high and the technologies are not applicable to many of the combustion systems in use today. Electrical discharges provide a means of producing active chemical species such as ions, radicals and metastable compounds that can react with oxides of nitrogen and cause their decomposition and removal from the gas stream. This study investigates the use of one such electrical discharge technique, barrier discharges. Experiments were conducted in a bench top apparatus and in a larger scale process development unit. The variables controlling the operation of the barrier discharge process and the products produced were identified and studied. They included electrical parameters such as applied voltage and frequency, the chemical composition of the gas stream, and flow conditions in the barrier discharge reactor. Experimental results showed that greater than 95% conversion of nitric oxide could be achieved using both simulated and combustion generated flue gas. Products of the reactions leading to nitric oxide destruction were non-polluting nitrogen and oxygen when dry, simulated flue gas was used. Nitric acid was produced when the gas stream contained water vapor. Operation of the barrier discharge system established on the bench scale apparatus was verified on the process development unit. Results of this work have the potential to establish the foundation for a nitrogen oxides control technology that is more versatile and may cost less to install and operate than existing control techniques