Emergence and spread of two SARS-CoV-2 variants of interest in Nigeria.

Identifying the dissemination patterns and impacts of a virus of economic or health importance during a pandemic is crucial, as it informs the public on policies for containment in order to reduce the spread of the virus. In this study, we integrated genomic and travel data to investigate the emergence and spread of the SARS-CoV-2 B.1.1.318 and B.1.525 (Eta) variants of interest in Nigeria and the wider Africa region. By integrating travel data and phylogeographic reconstructions, we find that these two variants that arose during the second wave in Nigeria emerged from within Africa, with the B.1.525 from Nigeria, and then spread to other parts of the world. Data from this study show how regional connectivity of Nigeria drove the spread of these variants of interest to surrounding countries and those connected by air-traffic. Our findings demonstrate the power of genomic analysis when combined with mobility and epidemiological data to identify the drivers of transmission, as bidirectional transmission within and between African nations are grossly underestimated as seen in our import risk index estimates

BARLEY YIELD AND PROTEIN RESPONSE TO NITROGEN AND SULFUR FERTILIZER RATES AND APPLICATION TIMING

The introduction of new barley varieties and changes in management practices necessitate re-evaluating nitrogen (N) and sulfur (S) nutrient management and application timing guidelines. Nitrogen has a significant impact on barley grain quality and yield. However, overapplication of N can result in yield reduction, groundwater pollution, and high protein content, resulting in lower end-use quality of barley, while underapplication of N results in reduced grain quality and yield. Because S improves N utilization and enhances protein synthesis and split N application improves yield and N use efficiency in winter barley, split N application timing and the interaction of N and S may be a valuable tool to reduce N loss, increase yield, improve grain quality, and improve N use efficiency for agronomically optimal spring barley production. In a bid to provide barley growers in the Western US with an optimal N application timing, as well as appropriate N and S rates for improved yields and grain quality and reduced input costs and environmental contamination, we evaluated the effects of N and S fertilizer rates and application timing on malt, feed, and food barley grain yield and quality for four site-years in Aberdeen and Kimberly Research and Extension Centers and Brigham Young University-Idaho in Idaho for the 2021 and 2022 growing seasons. Three barley varieties: malt (Moravian 179), feed (Claymore), and food (Julie) were grown at 1,980,000 seeds ha-1. Nitrogen fertilizer treatments included urea (46-0-0) applied at 0, 45, 90, 135, or 180 kg N ha-1 at planting or a split application of 45 kg N ha-1 done at planting and top-dressed with 23, 45, or 90 kg N ha-1 at heading. Sulfur fertilizer treatments included three S rates of potassium sulfate (0-0-53-18) fertilizer applied at 0, 17, or 34 kg S ha-1 at planting. Data was collected on grain yield, protein concentration, plant height, harvest heads, test weight, kernel plumpness, and N use efficiency.We investigated fertilizer rates for N and S, but S did not affect yield and yield components due to the high S concentration in the irrigation water. Plant height, harvest heads, and grain yield increased with increasing N rate for all varieties except at the Aberdeen 2021 field site, where grain yield was non-responsive to N due to the high preplant N at this location. The linear responses indicate N fertilizer insufficiency to maximize yield. Claymore had a quadratic response at Rexburg, with a maximum yield at approximately 120 kg N ha-1 rate. At the Aberdeen 2021 site, Julie responded to N and had a quadratic response with a maximum yield between 135-180 kg N ha-1. Grain protein concentration, test weight, and kernel plumpness were similar to those reported for Moravian 179, Claymore, and Julie in the southeastern and southcentral Idaho variety trials. Single N application produced similar or greater yields than split N application, contributing a 6-46% yield advantage over split N application across all varieties. Similarly, single N applications improved N use efficiency compared to split N applications and contributed a 9-25% N use efficiency advantage. For malt barley at Kimberly and Rexburg, split N application produced grains with 0.6-1.4% higher protein concentrations than acceptable for malting, suggesting an economic loss for growers as grains are sold as feed. This study demonstrated how pre-plant soil N content and N treatment timing affect spring barley yield and quality responses to N. Furthermore, we showed that the high S concentration in the irrigation water in this area negates the need for additional S fertilizer to maximize barley productivity and quality on the Snake River Plain. Split N applications are not an efficient way to increase yield, and N use efficiency for spring barley production and should be avoided in favor of a single N application at planting.masters, M.S., Plant Sciences -- University of Idaho - College of Graduate Studies, 2023-0

Particulate air pollution and noise:Assessing commuter exposure in Africa's most populous city

Africa is rapidly urbanising, consequently, there is the growing relevance of daily air pollution and noise exposure during urban commuting. Yet, little is known about commuter exposures in Africa. Lagos has a population in excess of nine million people, and approximately 788,000 registered motor vehicles. We monitored exposures of commuters within the Lagos metropolis to various size fractions of particulate air pollution, black carbon, and noise while traveling by car (taxi), microbus and larger bus with an aim to determine exposure levels and compare between modes. We conducted, altogether, 139 trips on nine designated commuting routes. The highest exposures were recorded when vehicle windows were open and air-conditioners turned off. For example, mean gravimetric PM10 levels of 364, 489 and 280 µg/m3, and mean particle number count (PNC) levels of 92, 52 and 27 (x 103 pc /cm3) were recorded in the car, microbus and larger bus, respectively. With the closed window setting, considerable reduction in particulate matter (PM) concentration was recorded on larger buses compared with cars. The highest mean (85 dB(A)) and highest mean 99th percentile (92 dB(A)) noise levels were obtained during trips on microbuses when windows were left open. This study observed remarkably high particulate air pollution and noise exposures during commuting in the major African city. A major shift to modern mass transportation systems would limit commuter exposure.</p