Particle filters with random resampling times

The ability to analyse, interpret and make inferences about evolving dynamical systems is of great importance in different areas of the world we live in today. Examples of such areas include audio engineering, finance and econometrics. In general, the dynamical systems are not directly measureable and only incomplete observations, quite often deteriorated by the presence noise are available. This leads us to the main objective of stochastic filtering: the estimation of an evolving dynamical system whose trajectory is modelled by a stochastic process called the signal, given the information available through its partial observation. Particle filters, which use clouds of weighted particles that evolve according to the law of the signal process, can be used to approximate the solution of the filtering problem. In time, as some of the particles become redundant, a procedure which eliminates these particles and multiplies the ones that contribute most to the resulting approximation is introduced at points in time called resampling/correction times. Practitioners normally use certain overall characteristics of the approximating system of particles (such as the effective sample size of the system) to determine when to correct the system. There are currently no results to justify the convergence of particle filters with random correction times to the solution of the filtering problem in continuous time. In this thesis, we analyse particle filters in a continuous time framework where resampling takes place at times that form a sequence of (predictable) stopping times. The particular focus will be on the case where the signal is a diffusion process on a d-dimensional Euclidean space. We will also look at central limit theorem type results for the approximating particle system. The results will then be used to make inferences about the threshold used in the effective sample size approach of approximating the signal

Depletion of Branched-Chain Aminotransferase 2 (BCAT2) Enzyme Impairs Myoblast 3 Survival and Myotube Formation

Much is known about the positive effects of branched-chain amino acids (BCAA) in regulating muscle protein metabolism. Comparatively much less is known about the effects of these amino acids and their metabolites in regulating myotube formation. Using cultured myoblasts, we showed that although leucine is required for myotube formation, this requirement is easily met by α-ketoisocaproic acid, the ketoacid of leucine. We then demonstrated increases in the expression of the first two enzymes in the catabolism of the three BCAA, branched-chain amino transferase (BCAT2) and branched-chain α-ketoacid dehydrogenase (BCKD), with ~3× increase in BCKD protein expression (p < .05) during differentiation. Furthermore, depletion of BCAT2 abolished myoblast differentiation, as indicated by reduction in the levels of myosin heavy chain-1, troponin and myogenin. Supplementation of incubation medium with branched-chain α-ketoacids or related metabolites derivable from BCAT2 functions did not rescue the defects. However, co-depletion of BCKD kinase partially rescued the defects. Collectively, our data indicate a requirement for BCAA catabolism during myotube formation and that this requirement for BCAT2 likely goes beyond the need for this enzyme to generate the α-ketoacids of the BCAA.York University Librarie

The Critque of the Communitarians Arguments from an African Perspective

The communitarians claim that the individual is a natural member of the human society but that he needs the society and all the opportunities it makes available for the realization of his potential for living a life that is meaningful This claim is synonymous to African conception of individual and the community Thus this work set out to carry out the critique of some notable communitarians such as John Dewey Fredrick Hegel and Michael Sandel Macinyre Alasdair Charles Taylor We discovered in the work that the claim of these theorists on individual and community is identical to African ideal And the critique exposes the inadequacies in their claim as well as the African ideal because development today is beyond the narrow context of communal life which puts African under the illusion that communities constitute a paradise lost As such there is the need for African to seek their rights this will enable them to function properly in the global scheme of thing

Investing in communities is key in mitigating Nigeria's extreme weather events

The 2022 severe floods and landslides in Nigeria highlight how vulnerable the country is to multiple risks and impacts of such extreme events. Scientists have attributed the recent rising sea level and frequent flooding to climate change. Despite Nigeria’s commitment to achieving net-zero by 2060, Olasunkanmi Okunola wonders whether such policy commitments and macro interventions are enough to mitigate subsequent flood occurrences in the country and if there is a political will to transform communities at risk into resilient and sustainable communities

The Sensitivity of Pseudomonas Agar Plaque Assay in the Isolation of Bacteriophage Φ6 in the Environment: A pilot study

Background: Bacteriophage Φ6 is a lipid-enveloped dsRNA bacteriophage. The limitations in our knowledge of how this bacteriophage occurs in the environment are limited by non-selective isolation techniques. Research on finding phages in the environment in the past has employed the Double Agar Layer (DAL) plaque assay using Tryptic Soy Agar (TSA), a non-selective media. The bacterial host for bacteriophage Φ6 is Pseudomonas syringae. In this study, we tested Pseudomonas Agar, a selective media that suppresses the growth of bacteria except Pseudomonas species, in the standard double agar layer plaque assay for Φ6. Methods: DAL plaque assays were performed to determine the sensitivity of both Tryptic Soy Agar (TSA) and Pseudomonas Agar (PA) for determining the titer of pure bacteriophage Φ6 stocks. We used Pseudomonas syringae (HB10Y) as the host, and the plaque formation on both agars was compared. Following the evaluation of PA with pure Φ6 stocks, PA effectiveness for Φ6 isolation from environmental samples was tested in spiked waters obtained from irrigation ponds at an agricultural farm. Results: Comparison of TSA and PA using pure Φ6 cultured in the laboratory and spiked environmental samples showed that PA agar can detect bacteriophage Φ6 as well as the standard DAL assay using TSA. On PA, formation of clear visible plaques comparable to the plaques formed using TSA was observed. Conclusions: Pseudomonas Agar can be used for the isolation of bacteriophage Φ6 in environmental samples. This may enhance the detection of these phages in the environment

Climate Change Vulnerability and Adaptation in the city of Lagos, Nigeria

Coastal cities worldwide, located in low-lying topography are faced with challenges arising from climate-change-induced events such as sea-level rise, storm surges and coastal erosion, exacerbated by rapid urban growth, lack of awareness, and limited knowledge of flood risks and solutions. This research focuses on Lagos, a Nigerian mega-city already under impact by frequent floods, erosion and storm surges. The paper uses concepts of vulnerability, resilience, adaptation and adaptive capacity of communities to analyze adaptation strategies. The paper also analyzes the strategies of the coastal cities that results to adaptation, such as New Orleans, Amsterdam and Dhaka in Bangladesh all of which share similar problems with Lagos but are developing interesting solutions in terms of infrastructure, planning, and resilient policy frameworks. The research uses a mixed-method approach that relies on analysis of peer-reviewed literature and my own knowledge as a planner in Lagos. The work also puts forward solutions aimed at helping improve Lagos?s adaptive capacity and its governmental policy framework, particularly regarding climate change resilience, flooding prevention and erosion solutions

How policy can address frequent flooding in African coastal cities

Climate change has exacerbated the risk of flooding in African coastal cities. For many countries, the cost of dealing with flood damage is a significant share of national GDP, which restrains investment into other development goals. With the frequency of major flooding events set to increase, Olasunkanmi Habeeb Okunola outlines the framework for a government policy response

Fiscal Policy Shocks and Private Consumption in Nigeria: Blanchard-Perotti (2002) Approach

This paper examines the effects of fiscal policy shocks on private consumption in Nigeria. Albeit, there is a considerable number of works examining the effects of fiscal policy shocks on private consumption globally but in Nigeria, no study has used the structural VAR approach by Blanchard and Perotti (2002) as used in this paper. This approach relies on institutional information about the tax and transfer systems and the timing of tax collection to identify the automatic response of taxes and spending to private consumption as well as to infer fiscal shocks. The key result of this paper is that positive government spending shocks in Nigeria have an instantaneous negative effect on private consumption. The effect becomes significant in the period following the shock. Also, positive tax shocks have a negative effect on private consumption in the period of a shock and the effect becomes statistically insignificant afterwards. On this premises, one-off changes in government spending and taxes in Nigeria are long-lived and short-lived respectively. Thus, the government expenditure changes can be used to support private consumption in the long-run while that of taxes can only be used to support private consumption for a short period

Treatment of persistent organic pollutants in wastewater with combined advanced oxidation

Philosophiae Doctor - PhDPersistent organic pollutants (POPs) are very tenacious wastewater contaminants with negative impact on the ecosystem. The two major sources of POPs are wastewater from textile industries and pharmaceutical industries. They are known for their recalcitrance and circumvention of nearly all the known wastewater treatment procedures. However, the wastewater treatment methods which applied advanced oxidation processes (AOPs) are documented for their successful remediation of POPs. AOPs are a group of water treatment technologies which is centered on the generation of OH radicals for the purpose of oxidizing recalcitrant organic contaminants content of wastewater to their inert end products. Circumvention of the reported demerits of AOPs such as low degradation efficiency, generation of toxic intermediates, massive sludge production, high energy expenditure and operational cost can be done through the application of the combined AOPs in the wastewater treatment procedure. The resultant mineralisation of the POPs content of wastewater is due to the synergistic effect of the OH radicals produced in the combined AOPs. Hydrodynamic cavitation is the application of the pressure variation in a liquid flowing through the venturi or orifice plates. This results in generation, growth, implosion and subsequent production of OH radicals in the liquid matrix. The generated OH radical in the jet loop hydrodynamic cavitation was applied as a form of advanced oxidation process in combination with hydrogen peroxide, iron (II) oxides or the synthesized green nano zero valent iron (gnZVI) for the treatment of simulated textile and pharmaceutical wastewater

Power Struggle in Ola Rotimi’s Kurunmi and Toyin Abiodun’s The Trials of Afonja

A major cause of crises in various strata of the human society is power struggle in different layers. Ola Rotimi’s Kurunmi and Toyin Abiodun’s The Trials of Afonja exemplify historical African plays which have been copiously previously studied. However, most of the existing studies on these plays have failed to address the issue of power struggles in these plays, despite the fact that power struggle is central to the plays, and is a cardinal issue which is of urgent currency in African continent and different parts of the globe. Power struggle has put a cog in the wheel of progress of many a country across the globe. This study is an enterprise at filling this gap. It examines the various instances of power struggles in Ola Rotimi’s Kurunmi, and Toyin Abiodun’s The Trials of Afonja. Foucault’s Discourse Analysis provides the theoretical framework of the study. In the two plays examined, there is power struggle among several characters. In Kurunmi, there is power struggle between Kurunmi and Adelu, Kurunmi and the Ibadan chiefs, Ogunmola and Ibikunle, and Ibadan and Ijaye. In The Trials of Afonja, Afonja and Alaafin Aole, Afonja and the Oyo warriors, and Afonja and Alimi are locked in power struggles. In addition, figures in authority habitually use language to express their dominance and request obedience from those subordinate to them. The paper submits that Ola Rotimi and Toyin Abiodun employ power struggles among several characters not only to propel the plots of their plays but also to foreground the historical and socio-cultural backgrounds of the plays.