The Character and Distribution of Cu-PGE Mineralization at the Geordie Lake Deposit Within the Coldwell Complex, Ontario

Cu-PGE mineralization at the Geordie Lake Deposit (GLD) is spatially associated with weak to intense actinolite and albite alteration within gabbro and troctolite. Previous studies have determined a magmatic, and magmatic-hydrothermal origin of the deposit. The most significant Cu-PGE occurrence in the GLD is dominantly stratiform, and in contact with a basal syenite. Similar patterns of REE with progressive enrichment from troctolite, to gabbro, and basal syenite indicate that these lithologies are genetically linked. Major element geochemistry shows no discernable variation between the altered and unaltered samples. Whole rock δ18O analyses were conducted in equal intervals down the stratigraphy of the GLD revealing asteady depletion in δ18O from 5.1‰ at the surface of the deposit, to 1.3 ‰ at the basal contact with cross-cutting syenite. The results show that sulfide deposition is magmatic, though interaction with late stage magmatic fluid redistributed some sulfide components

Rationalising racial inequality: ideology, hegemony and post-racialism among the Black and South Asian middle classes

Drawing upon 38 qualitative interviews with Black and South Asian middle-class individuals we theorise post-racialism as a hegemonic ideology. While research tends to focus on how racialised people experience racial inequality, some of our participants rationalised such inequality through a post-racial understanding. This post-racial understanding involves commitments to racial progress and transcendence, the view that racism is no longer a societal issue; race-neutral universalism, the belief that we live in a colourblind meritocracy; and a moral equivalence between anti-racism and anti-racialism, allowing for forms of ‘cultural’ racial prejudice. We examine how these components of post-racialism travel from the political macro-ideological level, to the micro-phenomenological level. Through this analysis we argue that these post-racial rationalisations are not the result of false consciousness, but reflect how post-racialism, as a hegemonic ideology, can manifest itself as common-sense and consistent with particular individuals’ histories of mobility and success

Keynote Address

Keynote address presented virtually at the Washington and Lee Law Review\u27s 54th Annual Lara D. Gass Symposium: The Future of E-Commerce: Is It on a Blockchain? on Friday, March 17, 2023 in Lexington, Virginia

On a Joint Physical Layer and Medium Access Control Sublayer Design for Efficient Wireless Sensor Networks and Applications

Wireless sensor networks (WSNs) are distributed networks comprising small sensing devices equipped with a processor, memory, power source, and often with the capability for short range wireless communication. These networks are used in various applications, and have created interest in WSN research and commercial uses, including industrial, scientific, household, military, medical and environmental domains. These initiatives have also been stimulated by the finalisation of the IEEE 802.15.4 standard, which defines the medium access control (MAC) and physical layer (PHY) for low-rate wireless personal area networks (LR-WPAN). Future applications may require large WSNs consisting of huge numbers of inexpensive wireless sensor nodes with limited resources (energy, bandwidth), operating in harsh environmental conditions. WSNs must perform reliably despite novel resource constraints including limited bandwidth, channel errors, and nodes that have limited operating energy. Improving resource utilisation and quality-of-service (QoS), in terms of reliable connectivity and energy efficiency, are major challenges in WSNs. Hence, the development of new WSN applications with severe resource constraints will require innovative solutions to overcome the above issues as well as improving the robustness of network components, and developing sustainable and cost effective implementation models. The main purpose of this research is to investigate methods for improving the performance of WSNs to maintain reliable network connectivity, scalability and energy efficiency. The study focuses on the IEEE 802.15.4 MAC/PHY layers and the carrier sense multiple access with collision avoidance (CSMA/CA) based networks. First, transmission power control (TPC) is investigated in multi and single-hop WSNs using typical hardware platform parameters via simulation and numerical analysis. A novel approach to testing TPC at the physical layer is developed, and results show that contrary to what has been reported from previous studies, in multi-hop networks TPC does not save energy. Next, the network initialization/self-configuration phase is addressed through investigation of the 802.15.4 MAC beacon interval setting and the number of associating nodes, in terms of association delay with the coordinator. The results raise doubt whether that the association energy consumption will outweigh the benefit of duty cycle power management for larger beacon intervals as the number of associating nodes increases. The third main contribution of this thesis is a new cross layer (PHY-MAC) design to improve network energy efficiency, reliability and scalability by minimising packet collisions due to hidden nodes. This is undertaken in response to findings in this thesis on the IEEE 802.15.4 MAC performance in the presence of hidden nodes. Specifically, simulation results show that it is the random backoff exponent that is of paramount importance for resolving collisions and not the number of times the channel is sensed before transmitting. However, the random backoff is ineffective in the presence of hidden nodes. The proposed design uses a new algorithm to increase the sensing coverage area, and therefore greatly reduces the chance of packet collisions due to hidden nodes. Moreover, the design uses a new dynamic transmission power control (TPC) to further reduce energy consumption and interference. The above proposed changes can smoothly coexist with the legacy 802.15.4 CSMA/CA. Finally, an improved two dimensional discrete time Markov chain model is proposed to capture the performance of the slotted 802.15.4 CSMA/CA. This model rectifies minor issues apparent in previous studies. The relationship derived for the successful transmission probability, throughput and average energy consumption, will provide better performance predictions. It will also offer greater insight into the strengths and weaknesses of the MAC operation, and possible enhancement opportunities. Overall, the work presented in this thesis provides several significant insights into WSN performance improvements with both existing protocols and newly designed protocols. Finally, some of the numerous challenges for future research are described

Construction and Development of Bioluminescent Pseudomonas aeruginosa Strains; Application in Biosensors for Preservative Efficacy Testing

Whole cell biosensors have been extensively used for monitoring toxicity and contamination of compounds in environmental biology and microbial ecology. However, their application in the pharmaceutical and cosmetics industries for preservative efficacy testing (PET) has been limited. According to several pharmacopoeias, preservatives should be tested for microbial activity using traditional viable count techniques; the use of whole cell microbial biosensors potentially provides an alternative, fast, and efficient method. The aim of the study was to construct and develop whole cell microbial biosensors with Pseudomonas aeruginosa ATCC 9027. Constitutive promoters: PlysS, Pspc, Ptat, Plpp and PldcC and the lux-cassette were inserted into plasmid pME4510 and transformed into P. aeruginosa ATCC 9027 cells to produce bioluminescent strains. Plasmids were found to be maintained stably (~50 copies per cell) throughout the growth and death cycle. The novel bioluminescent strains were validated in accordance with the pharmacopoeia using bioluminescence detection and quantification followed by comparison with the traditional plate counting method. The bioluminescent method was found to be accurate, precise and equivalent at a range of 103 – 107 CFU/mL, as compared with plate counting. Recovery of bacterial cells was quantified using bioluminescence; this method proved to be accurate with percentage recoveries between 70-130% for all bioluminescent strains. The method was also more precise (relative standard deviation less than 15%) than the traditional plate counting method or the ATP bioluminescent method. Therefore, the bioluminescent constructs passed/exceeded pharmacopoeial specified criteria for range, limit of detection, accuracy, precision and equivalence. Physiology of the validated bioluminescent strains was studied by assessing the growth and death patterns using constitutive gene expression linked with bacterial replication. Promoter strengths were evaluated at various stages of the growth and death pattern and related to promoter sequences. PlysS, Ptat and Plpp were relatively strong promoters whilst PldcC and Pspc were relatively weak promoters. Relative promoter strength decreased in the order of Plpp>Ptat>PlysS>PldcC>Pspc during the exponential phase whilst Ptat was stronger than Plpp during the stationary phase of growth. Plpp had its highest level of expression during the exponential phase, while Ptat had relatively stable lux expression during the stationary phase. Correlations between relative bioluminescence and CFU at 24 hours were greater than 0.9 indicating a strong relationship for all bioluminescent strains. Reduction in correlation coefficients to approximately 0.6 between relative bioluminescence and CFU and between relative fluorescence and CFU beyond 24 hours indicated that a certain proportion of cells were viable but non-culturable. Tat-pME-lux showed steady bioluminescence compared to CFU count (R>0.9) throughout 28 days of growth. Equivalence analysis showed no significant difference between the bioluminescence and plate count method throughout 28 days of growth for all five bioluminescent strains. Applicability of these novel bioluminescent strains was evaluated for preservative efficacy tests (PET) using bacterial replication and bioluminescence as a measure of constitutive gene expression. PET using benzalkonium chloride and benzyl alcohol showed no significant difference between the bioluminescent method and the plate count method. Good correlations between bioluminescence, CFU count and fluorescence were obtained for benzalkonium chloride (BKC) concentrations (R>0.9) between 0.0003% and 0.0025% against strains lysR25, lppR4 and tatH5. Similarly, good correlations (R>0.9) between the three parameters were obtained for benzyl alcohol (BA) concentrations between 0.125% and 2% against strains lysR25, lppR4 and tatH5. The bioluminescent method and traditional plate counting method were equivalent for concentrations of BKC (0.0003 - 0.02%) and BA (0.25 - 2%) during preservative efficacy tests. These bioluminescent constructs therefore are good candidates for selection for preservative efficacy testing. The bioluminescent method and traditional plate counting method were also found to be equivalent for construct tatH5 at a concentration of 0.125% BA. PET testing with BKC and BA showed that tatH5-pMElux (R>0.9) had consistently high correlation coefficients between CFU and relative bioluminescence. Together with the results from growth and death kinetics, where tatH5 showed the greatest constitutive expression, it can be concluded that P. aeruginosa ATCC 9027 tatH5-pMElux is the best construct for testing various antimicrobial agents. This study has shown that according to the pharmacopoeial requirements, the bioluminescent method is more accurate, precise and equivalent to the traditional plate counting method and therefore can be utilised instead of the traditional plate counting method for the purpose of preservative efficacy testing

Can Blockchain Lead us to Forest Sovereignty? A future imagining of more-than-human relations.

This work endeavoured on a preliminary futuristic imagining of what it would take for Forest to practice its sovereignty in our current system. The concept of Forest Sovereignty is employed to mitigate against the challenges identified in this work within the forest governance space in Canada. As an attempt to make this imagining real, the practice of governance is leveraged to anchor the concept of Forest Sovereignty. Because there are signals in the Web 3.0 space that are exploring ways in which natural resources, particularly Forest, may be governed differently, blockchain technology is explored as a tool to do this. While it is determined that blockchain technology is not sufficient, it is revealed that this research question is essentially an exploration into two significant matters: 1) understanding that this question is essentially exploring the relationship between a natural entity (forest) and a piece of technology (blockchain), and 2) ways in which we, humans, may be able to engage more-than-human beings in meaningful ways as an attempt to shift away from human-centric systems. This shift is considered vital as human beings continue to demonstrate a lack of regard towards Earth. Keywords: Forest Governance, Blockchain, Non-Human Relations, Web 3.0, Natural and Tech System Merger

Noncommunicable Respiratory Disease and Air Pollution Exposure in Malawi (CAPS). A Cross-Sectional Study.

RationaleNoncommunicable respiratory diseases and exposure to air pollution are thought to be important contributors to morbidity and mortality in sub-Saharan African adults.ObjectivesWe set out to explore the prevalence and determinants of noncommunicable respiratory disease among adults living in Chikhwawa District, Malawi.MethodsWe performed a cross-sectional study among adults in communities participating in a randomized controlled trial of a cleaner-burning biomass-fueled cookstove intervention (CAPS [Cooking and Pneumonia Study]) in rural Malawi. We assessed chronic respiratory symptoms, spirometric abnormalities, and personal exposure to air pollution (particulate matter <2.5 μm in aerodynamic diameter [PM2.5] and carbon monoxide [CO]). Weighted prevalence estimates were calculated; multivariable and intention-to-treat analyses were done.Measurements and main resultsOne thousand four hundred eighty-one participants (mean [SD] age, 43.8 [17.8] yr; 57% female) were recruited. The prevalence of chronic respiratory symptoms, spirometric obstruction, and restriction were 13.6% (95% confidence interval [CI], 11.9-15.4), 8.7% (95% CI, 7.0-10.7), and 34.8% (95% CI, 31.7-38.0), respectively. Median 48-hour personal PM2.5 and CO exposures were 71.0 μg/m3 (interquartile range [IQR], 44.6-119.2) and 1.23 ppm (IQR, 0.79-1.93), respectively. Chronic respiratory symptoms were associated with current/ex-smoking (odds ratio [OR], 1.59; 95% CI, 1.05-2.39), previous tuberculosis (OR, 2.50; 95% CI, 1.04-15.58), and CO exposure (OR, 1.46; 95% CI, 1.04-2.05). Exposure to PM2.5 was not associated with any demographic, clinical, or spirometric characteristics. There was no effect of the CAPS intervention on any of the secondary trial outcomes.ConclusionsThe burden of chronic respiratory symptoms, abnormal spirometry, and air pollution exposures in adults in rural Malawi is of considerable potential public health importance. We found little evidence that air pollution exposures were associated with chronic respiratory symptoms or spirometric abnormalities and no evidence that the CAPS intervention had effects on the secondary trial outcomes. More effective prevention and control strategies for noncommunicable respiratory disease in sub-Saharan Africa are needed. Clinical trial registered with www.isrctn.com (ISRCTN 59448623)

A Systematic Review of the Prevalence and Pattern of Imaging Defined Post-TB Lung Disease

Background Tuberculosis is an important risk factor for chronic respiratory disease in resource poor settings. The persistence of abnormal spirometry and symptoms after treatment are well described, but the structural abnormalities underlying these changes remain poorly defined, limiting our ability to phenotype post-TB lung disease in to meaningful categories for clinical management, prognostication, and ongoing research. The relationship between post-TB lung damage and patient-centred outcomes including functional impairment, respiratory symptoms, and health related quality of life also remains unclear. Methods We performed a systematic literature review to determine the prevalence and pattern of imaging-defined lung pathology in adults after medical treatment for pleural, miliary, or pulmonary TB disease. Data were collected on study characteristics, and the modality, timing, and findings of thoracic imaging. The proportion of studies relating imaging findings to spirometry results and patient morbidity was recorded. Study quality was assessed using a modified Newcastle-Ottowa score. (Prospero Registration number CRD42015027958) Results We identified 37 eligible studies. The principle features seen on CXR were cavitation (8.3–83.7%), bronchiectasis (4.3–11.2%), and fibrosis (25.0–70.4%), but prevalence was highly variable. CT imaging identified a wider range of residual abnormalities than CXR, including nodules (25.0–55.8%), consolidation (3.7–19.2%), and emphysema (15.0–45.0%). The prevalence of cavitation was generally lower (7.4–34.6%) and bronchiectasis higher (35.0–86.0%) on CT vs. CXR imaging. A paucity of prospective data, and data from HIV-infected adults and sub-Saharan Africa (sSA) was noted. Few studies related structural damage to physiological impairment, respiratory symptoms, or patient morbidity. Conclusions Post-TB structural lung pathology is common. Prospective data are required to determine the evolution of this lung damage and its associated morbidity over time. Further data are required from HIV-infected groups and those living in sSA

What can the sociology of race learn from the histories of anti-colonialism?

This essay looks at three books on the histories of anti-colonialism: Desai’s the United States of India, Getachew’s Worldmaking after Empire, and Gopal’s Insurgent Empire. I argue that despite it not being the authors’ primary focus, these books collectively push forward the sociology of race. In particular, each of these books shows the importance for contemporary race and racism scholarship to adopt a transnational, temporally connected approach which is able to both study and forge global anti-colonial solidarities

Positionings of the black middle-classes: understanding identity construction beyond strategic assimilation

his paper explores the identities of Britain’s black middle-classes. Drawing upon interviews with seventy-two participants, I theorize a ‘triangle of identity’. This triangle emphasizes how black middle-class identities are constructed within the dynamics of three poles. Firstly, there is the class-minded pole whereby class comes to the fore as a conceptual scheme; secondly, there is the ethnoracial autonomous pole whereby ‘race’ is central to one’s identity and whiteness is actively resisted; and lastly there is the strategic assimilation pole, where one continually moves between classed and racialized spheres of action. This tripartite approach to identity builds upon previous research by further exploring the social, cultural and phenomenological distinctions within Britain’s black middle-classes