Fungi Associated with Common Buckthorn (Rhamnus cathartica) in Southern Ontario

Common buckthorn (Rhamnus cathartica) is a competitive Eurasian woody shrub currently invading North America. Buckthorn thickets reduce native diversity and may reduce mycorrhizal diversity through the release of allelochemicals. Two aspects of buckthorn’s invasional biology are explored: 1) identifying fungi associating with buckthorn, and 2) determining buckthorn’s allelochemical impacts on arbuscular mycorrhizae in forest soils and an open-greenhouse experiment. Twenty-three fungi were found growing on buckthorn, including Armillaria mellea s.l., Hypoxylon fuscum, H. perforatum, Nectria cinnabarina, and Cylindrobasidium evolvens. Data from invaded and uninvaded sugar maple (Acer saccharum) soils revealed that arbuscular mycorrhizal fungi (AMF) diversity fluctuated as a function of season or potting disturbance, but the presence of buckthorn had little effect on AMF development in maple roots. Buckthorn may be a mycorrhizal generalist, and changes in AMF abundance may be more influenced by underlying stochastic soil processes and aboveground plant composition than by buckthorn and its allelochemicals

Geochemical Constraints On The Future Of Agriculture In Sri Lanka

The economic mainstay of tropical Sri Lanka, is agriculture. Plantation monocultures earn 43% of export trade. Under natural conditions, tropical rainfall leads to a paradoxical combination of lush vegetation and infertile soils; regeneration is maintained through rapid recycling of litter. In monocultures nutrient removal is not similarly compensated for, as the increasing number of deficient nutrient element diagnoses indicate.;Distinct differences exist between Sri Lanka\u27s intensely cultivated Wet Zone soils and Dry Zone soils.;While Sri Lankan soils are reassuringly fertile compared to Amazon soils, average crustal levels of Na, Mg and Ca obtain in only {dollar}\sim{dollar}10% of Wet Zone soils sampled and in 33% for potassium (a major plant nutrient). Corresponding values for Dry Zone soils are Na(83%), Mg(14%), Ca(39%) and K(100%).;Mass balance calculations indicate that while K is slightly more resistant, less than 5% of parent rock Mg, Ca and Na remain in a Wet Zone soil. Ti vs. Zr plots (successfully used for the first time to discriminate soil horizons derived from gneissic banding) indicate extensive physical removal of soil particulates due to intense rainfall.;Groundwater percolation rates govern soil mineral formation. In the Wet Zone, oxyhydroxides and kaolin can be the first and last minerals to form since groundwaters remain dilute and aggressive. Primary minerals are nonexistent even within the silt fraction. Low percolation rates result in abundant primary minerals and smectitic clays in Dry Zone soils. Kaolin-smectite interstratification previously not identified in Sri Lanka may be common.;Wet Zone soils have a maximum 2 year supply of exchangeable potassium (compared to 3-4 years from Dry Zone soils) and if utilisable, total potassium reserves for 40 years (compared to 1000-2000 years for Dry Zone soils).;An adequate 50 kg/ha supply of exchangeable potassium, is equivalent to 34 tonnes of rock powder and would lead to logistical problems if substituted for fertiliser. However, when the new insight into weathering conditions of Wet Zone soils is considered it becomes clear that applications of rock powder and smectite are essential for long term soil maintenance, if these soils are to continue to support an agricultural economy

Separation of reducing sugars from lignocellulosic hydrolysate: Membrane experiments & system dynamic modelling

Separation of fermentable sugars after hydrolysis of lignocellulosic biomass plays a vital role in second-generation biofuel production. Byproducts and solid fractions generated during pretreatment and hydrolysis can have adverse effects on fermentation efficiency. Previous studies have shown that a maximum of 40% (w/w) of sugar yield can be obtained by sequential UF and NF permeate recovery. This study aimed to introduce a multi-step membrane filtration process to recover fermentable sugars while removing inhibitory bi-products. Fermentable sugar recovery was investigated using a recirculation flow between various stages of separation. The experimental results demonstrated that by introducing NF permeate recirculation to the UF unit a sequential UF/NF system can achieve 60% (w/w%) recovery of reducing sugars. Based on the experimental results, a ‘Simultaneous ultrafiltration and nanofiltration model’ was developed using system dynamics. The model was used to predict the final sugar concentration and sugar yield using sugar permeability in each membrane as the dynamic variability. The model predicts that high sugar permeability (or selective permeability) through the ultrafiltration mostly affects the efficiency of the system, which still is a challenge

Advancing Mathematical Models of Mycobacterium tuberculosis Transmission to Support Vaccine Introduction

INTRODUCTION: Tuberculosis causes substantial morbidity and mortality, with 10 million new cases and 1.5 million deaths per year worldwide. We may acquire a new tuberculosis prevention tool in the foreseeable future as the anti-tuberculosis vaccine candidate M72/AS01E is poised to enter phase III trials. If phase III trials demonstrate efficacy, we must ensure that models and model evidence are rapidly and reliably available to support decision making around whether to introduce the new vaccine. Prior mathematical models of tuberculosis vaccination have aimed to inform vaccine development, for example, by investigating the impact of varying vaccine durability and efficacy, or the host-infection status required for vaccine efficacy in low and high burden settings. These studies have identified vaccine characteristics most likely to achieve global tuberculosis control goals, providing core evidence for the World Health Organization (WHO) Preferred Product Characteristics for New Tuberculosis Vaccines. Collectively, this evidence has provided direction for vaccine research and development efforts, including the identification of indications and clinical trial endpoints. However, work to substantiate vaccine introduction, bridging the gap between development and broad-scale adoption, is limited. I address two aims in this thesis, corresponding to two research needs that we should meet to advance models to support vaccine introduction: 1. Estimate the epidemiologic impact, cost-effectiveness and affordability of new tuberculosis vaccines in India and China, incorporating drug-resistance transmission and acquisition. This aim reflects the need to adapt models to include locally important features of, and uncertainty in, tuberculosis epidemiology and health systems. 2. Describe how different assumptions of adapting social contact structures to long-term demographic trends in India—as a country undergoing the demographic transition—might affect vaccine impact estimates. This aim reflects the need to establish whether vaccine impact estimates are robust to structural decisions in model design. METHODS: I constructed an age-, drug-resistance, and treatment-history stratified difference equation-based dynamic transmission model of Mycobacterium tuberculosis, set in India and China, calibrated to epidemiologic data over 2000–2017. To this, I attached a country-specific cost model of programmatic tuberculosis control—including multidrug-resistant or rifampicin-resistant TB (MDR/RR-TB) diagnosis and treatment—and vaccine delivery. The calibrated model was used to estimate the epidemiologic impact and cost-effectiveness of a prevention-of-disease vaccine modelled on M72/AS01E, with 50% efficacy, conferring 10-years of protection over 2027–2050. To assess the affordability of vaccine deployment, I estimated the total cost of untargeted mass vaccination of all adults and adolescents (ages ≥ 10y) compared to 10-year wide age bands in India and China, while valuing the health benefits of vaccination at cost-effectiveness thresholds based on country-specific healthcare opportunity costs. Finally, I developed a second transmission model of tuberculosis to investigate whether adapting age-specific social contact patterns to evolving demography—using multiple update methods, each preserving different properties of social mixing matrices—affected model-based estimates of vaccine impact in an India-like scenario. Results Vaccination was found to substantially reduce future MDR/RR-TB in China and India, reducing incidence rate by 73% (uncertainty interval: 66–76) and 72% (UI: 65–77) in 2050, with a similar impact on drug-susceptible tuberculosis. In both countries, vaccination was found likely to be cost-effective at country-specific willingness to pay thresholds. Untargeted yet cost-effective large scale adult mass vaccination was estimated to require $21 billion (uncertainty interval: 16–27) and$15 billion (UI: 12–29) by 2050 in India and China, respectively. In India and China, targeting 50–59-year-olds and 60–69-year-olds, respectively, was found to avert the most disability-adjusted life-years per vaccine course delivered. Targeted yet cost-effective mass vaccination of these age groups was estimated to require $5 billion (UI: 4–6) and$6 billion (UI: 4–7) in India and China, respectively. Vaccine epidemiologic impact estimates remained robust to different methods of updating age-specific social contact structures to match secular trends in demography. Across a range of methods that spanned no updates to match demography, to methods that preserved both contact reciprocity (balanced total contacts between age groups) and assortativity (inherent preference for contact by age-group with another), the maximum difference in vaccine-mediated incidence rate reduction in 2050 was found to be 7%. CONCLUSIONS: In this thesis, I develop mathematical models that provide evidence to support decision making around tuberculosis vaccine introduction. This thesis makes three unique contributions to the tuberculosis vaccine modelling literature: estimating the impact of new tuberculosis vaccines on MDR/RR-TB, incorporating both direct and transmission effects of a vaccine, estimating the total maximum cost of large scale adult tuberculosis vaccination at country-specific healthcare opportunity cost-based thresholds, and investigating whether structural assumptions around how social contact patterns change with evolving demography affect estimates of vaccine impact. Vaccines are predicted to substantially and cost-effectively reduce the future burden of drug-resistant (and drug-susceptible) tuberculosis in India and China and could be an integral tool in MDR/RR-TB control efforts. The expected total cost of cost-effective untargeted mass adult vaccination for tuberculosis is likely to be substantial at current willingness-to-pay thresholds, but age-targeting may improve affordability. Funding for tuberculosis vaccines will require a careful situating within that for wider tuberculosis control efforts. Vaccine impact estimates may be reasonably robust to different methods of updating social contact patterns to evolving demography. This finding improves confidence in existing estimates of vaccine impact from long time-horizon models and increases the utility of model results in vaccine decision making. Overall, this thesis adds evidence in favour of tuberculosis vaccine introduction, contributing to the initial knowledge base that decision-makers may build on to address further context-specific questions regarding vaccine feasibility and implementation

Simultaneous dual channel phase regeneration in SOAs

For the first time we demonstrate simultaneous suppression of phase distortion on two independent 10.7 Gbit/s DPSK modulated signal wavelengths using semiconductor optical amplifiers, realizing a compact phase sensitive amplifier with low power consumption

Strategies for adopting new trends in wind load evaluation On structures

The advancement of knowledge of wind engineering introduces lots of changes to wind loading standards. There are many differences in old codes of practices compare to the newer standards by means of factors, methods and ultimately wind induced forces in structural members. Since tall buildings are more susceptible for wind loads and thus, require more close consideration when they are designed for wind loads. In this study, five major wind loading standards, CP 3 Chapter V – Part 2:1972, BS 6399.2:1997, AS 1170.2:1989, AS/NZS 1170.2:2002 and EN 1991-1-4:2005 are compared with respect to the CP 3 Chapter V – Part 2, for designing of a 183 m tall building. From one standard to another, factors like basic wind speeds, terrain height multiplier and procedures like analysis methods are different because of strategies set by the conditions and requirements of the country of its origin. The serviceability limit state behaviour of tall building is equally important like ultimate limit state behaviour and hence it discussed with this paper by the means of drift index and along and cross wind accelerations

All-optical phase and amplitude regeneration properties of a 40 Gbit/s DPSK black-box phase sensitive amplifier

We experimentally study the pure amplitude and phase regeneration capabilities of a blackbox degenerate four wave mixing (FWM) based bit-rate-flexible phase sensitive amplifier (PSA) for a 40 Gbit/s differential phase-shift keyed (DPSK) signal

Performance characterisation of 42.65 Gbit/s dual-gate asynchronous digital optical regenerator using single MZM

The tolerance of a 42.65 Gbit/s dual-gate asynchronous digital optical regenerator using a single Mach-Zehnder modulator to optical signal-to-noise-ratio degradation and chromatic dispersion is experimentally demonstrated

The Linear-Time-Invariance Notion of the Koopman Analysis-Part 2: Physical Interpretations of Invariant Koopman Modes and Phenomenological Revelations

This serial work presents a Linear-Time-Invariance (LTI) notion to the Koopman analysis, finding consistent and physically meaningful Koopman modes and addressing a long-standing problem of fluid-structure interactions: deterministically relating the fluid and structure. Part 1 (Li et al., 2022) developed the Koopman-LTI architecture and applied it to a pedagogical prism wake. By the systematic procedure, the LTI generated a sampling-independent Koopman linearization that captured all the recurring dynamics, finding six corresponding, orthogonal, and in-synch fluid excitation-structure response mechanisms. This Part 2 analyzes the six modal duplets' to underpin their physical interpretations, providing a phenomenological revelation of the subcritical prism wake. By the dynamical mode shape, results show that two mechanisms at St1=0.1242 and St5=0.0497 describe shear layer dynamics, the associated B\'ernard-K\'arm\'an shedding, and turbulence production, which together overwhelm the upstream and crosswind walls by instigating a reattachment-type of response. The on-wind walls' dynamical similarity renders them a spectrally unified fluid-structure interface. Another four harmonic counterparts, namely the subharmonic at St7=0.0683, the second harmonic at St3=0.2422, and two ultra-harmonics at St7 =0.1739 and St13=0.1935, govern the downstream wall. The 2P wake mode is also observed as an embedded harmonic of the bluff-body wake. Finally, this work discovered the vortex breathing phenomenon, describing the constant energy exchange in wake's circulation-entrainment-deposition processes. With the Koopman-LTI, one may pinpoint the exact excitations responsible for a specific structural response, or vice versa.Comment: 24 figures, 60 pages. Video files at https://drive.google.com/drive/folders/1AHdhUdAfNwlC1XUh-74PgQWW6jUHXJ5j?usp=sharin