Environmental Epidemiology of Intestinal Schistosomiasis in Uganda: Population Dynamics of Biomphalaria (Gastropoda: Planorbidae) in Lake Albert and Lake Victoria with Observations on Natural Infections with Digenetic Trematodes

This study documented the population dynamics of Biomphalaria and associated natural infections with digenetic trematodes, along the shores of Lake Albert and Lake Victoria, recording local physicochemical factors. Over a two-and-a-half-year study period with monthly sampling, physicochemical factors were measured at 12 survey sites and all freshwater snails were collected. Retained Biomphalaria were subsequently monitored in laboratory aquaria for shedding trematode cercariae, which were classified as either human infective (Schistosoma mansoni) or nonhuman infective. The population dynamics of Biomphalaria differed by location and by lake and had positive relationship with pH (P < 0.001) in both lakes and negative relationship with conductivity (P = 0.04) in Lake Albert. Of the Biomphalaria collected in Lake Albert (N = 6,183), 8.9% were infected with digenetic trematodes of which 15.8% were shedding S. mansoni cercariae and 84.2% with nonhuman infective cercariae. In Lake Victoria, 2.1% of collected Biomphalaria (N = 13,172) were infected with digenetic trematodes with 13.9% shedding S. mansoni cercariae, 85.7% shedding nonhuman infective cercariae, and 0.4% of infected snails shedding both types of cercariae. Upon morphological identification, species of Biomphalaria infected included B. sudanica, B. pfeifferi, and B. stanleyi in Lake Albert and B. sudanica, B. pfeifferi, and B. choanomphala in Lake Victoria. The study found the physicochemical factors that influenced Biomphalaria population and infections. The number and extent of snails shedding S. mansoni cercariae illustrate the high risk of transmission within these lake settings. For better control of this disease, greater effort should be placed on reducing environmental contamination by improvement of local water sanitation and hygiene

Scaling of the cumulative weights of the invasion percolation cluster on a branching process tree

We analyse the scaling of the weights added by invasion percolation on a uniformly weighted branching process tree. In this paper, we are interested in the invasion percolation cluster (IPC), obtained by performing invasion percolation for n steps and letting n → ∞. The volume scaling of the IPC was discussed in detail in [12] and in this work, we extend this analysis to the scaling of the cumulative weights. We assume a power-law offspring distribution on the branching process tree with exponent α. For α &gt; 2 and α ∈ (1, 2), we observe a natural law-of-large-numbers result, where the cumulative weights scale similar to the volume, but converge to a different limit. However, for α &lt; 1, where the weights added by invasion percolation vanish, the scaling changes significantly. For α ∈ (1/2, 1), the cumulative weights scale exponentially but with a different exponent than the volume scaling, while for α ∈ (0, 1/2) the cumulative weights are summable without any scaling. Such a phase transition at α = 1/2 is novel and unexpected as there is no significant change in the neighbourhood scaling of the IPC around α = 1/2.</p

Fiber-Reinforced Thermoelectric Tile As An Alternative Source Of Energy

Urban heating in modern cities that raises the temperature by 1℃ to 3℃ than the ordinary environment temperature due to the presence of high thermal mass materials present within the environment is a phenomenon called the Urban Heat Island Effect. These materials tend to store huge amount of thermal energy resulting to more humid environment temperature. This study proposes a method of reducing urban heating by converting thermal heat energy to electrical energy using fiber-reinforced thermoelectric tiles. The design of these tiles makes use of the concept of flywheel effect. Materials that possess high thermal mass can store thermal energy when the ambient temperature is higher than the material and releases it back when the ambient temperature is cooler. The study aims to convert the stored heat energy in materials to usable energy instead of being released back to the environment. This is accomplished by employing concrete cement mixed with carbon and aluminum fibers that act as n-type and p-type material, respectively, arranged in a way that one side is exposed to high temperature and the other side to low temperature. Result showed that a temperature difference between 15℃ and 35℃ can induce voltage and current between 0.75V to 1.80 V and 1.15A to 1.28 A,  respectively, for a 305 cm × 305 cm tile. Moreover, result showed that while converting the absorbed heat energy, the ambient temperature cools down faster compared to using typical concrete tiles

High Power Thermoelectrically Cooled and Uncooled Quantum Cascade Lasers With Optimized Reflectivity Facet Coatings

We present a method of preserving the device wall-plug efficiency by adjusting mirror losses with facet coatings for longer cavity quantum cascade lasers. An experimental study of output power and wall-plug efficiency as functions of mirror losses was performed by varying the front facet coating reflectivity with a high-reflectivity-coated rear facet. The use of optimized reflectivity coatings on 7-mm-long chips resulted in continuous-wave output power of 2.9 W at 293 K for thermoelectrically cooled devices mounted on AlN submounts and average and continuous-wave output power in excess of 1 W for uncooled devices emitting at 4.6 µm.Engineering and Applied Science

Scaling of the Cumulative Weights of the Invasion Percolation Cluster on a Branching Process Tree

We analyse the scaling of the weights added by invasion percolation on a branching process tree. This process is a paradigm model of self-organised criticality, where criticality is approach without a prespecified parameter. In this paper, we are interested in the invasion percolation cluster (IPC), obtained by performing invasion percolation for $n$ steps and letting $n\to\infty$. The volume scaling of the IPC was discussed in detail in (G\"undlach and van der Hofstad 2023) and in this work, we extend this analysis to the scaling of the cumulative weights of the IPC. We assume a power-law offspring distribution on the branching process tree with exponent $\alpha$. In the regimes $\alpha>2$ and $\alpha\in(1,2)$, we observe a natural law-of-large-numbers result, where the cumulative weights have the same scaling as the volume, but converge to a different limit. In the case $\alpha<1$, where the weights added by invasion percolation vanish, the scaling regimes change significantly. For $\alpha\in(1/2,1)$, the weights scale exponentially but with a different parameter than the volume scaling, while for $\alpha\in(0,1/2)$ it turns out that the weights are summable without any scaling. Such a phase transition at $\alpha=1/2$ of the cumulative weights is novel and unexpected as there is no significant change in the neighbourhood scaling of the IPC at $\alpha=1/2$.Comment: 14 pages, 1 figur

3 W Continuous-Wave Room Temperature Single-Facet Emission From Quantum Cascade Lasers Based On Nonresonant Extraction Design Approach

A strain-balanced, InP-based quantum cascade laser structure, designed for light emission at 4.6 $\mu$m using a new nonresonant extraction design approach, was grown by molecular beam epitaxy. Removal of the restrictive two-phonon resonant condition, currently used in most structure designs, allows simultaneous optimization of several design parameters influencing laser performance. Following the growth, the structure was processed in buried heterostructure. Maximum single-ended continuous-wave optical power of 3 W was obtained at 293 K for devices with stripe dimensions of 5 mm 11.6 $\mu$m. Corresponding maximum wallplug efficiency and threshold current density were measured to be 12.7% and 0.86 kA/cm$^{2}$.Physic

Indigenous Learning: Weaving the Fabric of Our Histories for Success

Six public housing community leaders were interviewed for this study. Four themes for recognizing indigenous learning were identified. Themes explained leadership style, validation of and motivation for leadership, and personal impact. The findings give rise to considerations of how adult educators can identify and begin to understand indigenous learning systems