Fire effects and litter accumulation dynamics in a montane longleaf pine ecosystem

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Title from PDF of title page (University of Missouri--Columbia, viewed on October 16, 2009).Thesis advisor: Dr. Richard P. Guyette.M.S. University of Missouri--Columbia 2009.A common obstacle for public land managers developing fire management plans in the eastern and southern United States is the lack of quantitative information on historic fire regimes and the effects that varying fine fuel loadings can produce. Despite the ecological importance of litter, little is known about the effects of litter accumulation and decay rates in the montane longleaf pine (Pinus palustris Mill.) region. Historic fire information helps to set target goals for wildland fire practices and fuels management. In this thesis, four centuries of past fire regimes on the Talladega National Forest in northeastern Alabama are described along with litter dynamics of recent prescribed burning practices. Seasonally distinguishable fire events from 372 tree-ring dated fire scars were used to reconstruct past fire regimes. Litter accumulation, combined litter measurements, and model estimates were used to derive decay constants that characterize montane longleaf pine. The fire regime prior to the early 19th century was characterized by a mean fire interval (MFI) of 3 years. The onset of EuroAmerican settlement in the mid-19th century changed the fire regime to 2.5 years. The number of fires decreased during the 20th century due to changes in land use, anthropogenic influences and climate-fire relationships. Litter accumulation equations were used to demonstrate temporal changes in litter loading. For example, after a fire event that consumes nearly 100 percent of the litter, about 35 percent of the litter accumulation equilibrium is reached within 1 year, 58 percent within 2 years, and the equilibrium (99 percent accumulation) after approximately 10 years. These results can be used to determine the appropriate prescribed burning intervals for a desired fire severity.Includes bibliographical references

Garden and landscape-scale correlates of moths of differing conservation status: significant effects of urbanization and habitat diversity

Moths are abundant and ubiquitous in vegetated terrestrial environments and are pollinators, important herbivores of wild plants, and food for birds, bats and rodents. In recent years, many once abundant and widespread species have shown sharp declines that have been cited by some as indicative of a widespread insect biodiversity crisis. Likely causes of these declines include agricultural intensification, light pollution, climate change, and urbanization; however, the real underlying cause(s) is still open to conjecture. We used data collected from the citizen science Garden Moth Scheme (GMS) to explore the spatial association between the abundance of 195 widespread British species of moth, and garden habitat and landscape features, to see if spatial habitat and landscape associations varied for species of differing conservation status. We found that associations with habitat and landscape composition were species-specific, but that there were consistent trends in species richness and total moth abundance. Gardens with more diverse and extensive microhabitats were associated with higher species richness and moth abundance; gardens near to the coast were associated with higher richness and moth abundance; and gardens in more urbanized locations were associated with lower species richness and moth abundance. The same trends were also found for species classified as increasing, declining and vulnerable under IUCN (World Conservation Union) criteria

Parker Solar Probe Observations of High Plasma Beta Solar Wind from Streamer Belt

In general, slow solar wind from the streamer belt forms a high plasma beta equatorial plasma sheet around the heliospheric current sheet (HCS) crossing, namely the heliospheric plasma sheet (HPS). Current Parker Solar Probe (PSP) observations show that the HCS crossings near the Sun could be full or partial current sheet crossing (PCS), and they share some common features but also have different properties. In this work, using the PSP observations from encounters 4 to 10, we identify streamer belt solar wind from enhancements in plasma beta, and we further use electron pitch angle distributions to separate it into HPS solar wind that around the full HCS crossings and PCS solar wind that in the vicinity of PCS crossings. Based on our analysis, we find that the PCS solar wind has different characteristics as compared with HPS solar wind: a) PCS solar wind could be non-pressure-balanced structures rather than magnetic holes, and the total pressure enhancement mainly results from the less reduced magnetic pressure; b) some of the PCS solar wind are mirror unstable; c) PCS solar wind is dominated by very low helium abundance but varied alpha-proton differential speed. We suggest the PCS solar wind could originate from coronal loops deep inside the streamer belt, and it is pristine solar wind that still actively interacts with ambient solar wind, thus it is valuable for further investigations on the heating and acceleration of slow solar wind

The impact of aluminosilicate-based additives upon the sintering and melting behaviour of biomass ash

The composition of ash arising from biomass combustion can cause significant slagging and fouling issues in pulverised-fuel boilers, particularly if high concentrations of alkalis are present. Al–Si additives have shown promise in improving the ash deposition characteristics of troublesome biomass, converting volatile potassium to potassium aluminosilicates. This article presents results of lab-scale testing for two high-potassium biomass ashes, olive-cake (OCA) and white-wood (WWA), combined with two promising additives, coal pulverised fuel ash (PFA) and kaolin powder, at 5% mass fraction. Ash fusion testing results show that the use of these additives consistently increases flow temperatures. For WWA, kaolin was observed to reduce deformation temperatures and increase flow temperatures to far above combustion temperatures. Sinter strength testing showed that additive use significantly improves the deposition properties of OCA, preventing the precipitation of KCl and formation of deposits that are highly undesirable for removal via sootblower. Sintering was eliminated at all temperatures measured with the use of kaolin. Both additives had negative effects upon the sintering of WWA, indicating that Al–Si additive use should be restricted to high K, high Cl biomass. High temperature viscometry of OCA, combined with thermodynamic modelling, showed that viscosities at combustion temperatures were far below ideal values due high Mg concentration and silicate formation. Kaolin at 5% mass fraction was predicted to significantly improve this behaviour, with aluminosilicate formation producing favourable viscosities. Results indicate that kaolin addition to high K, high Cl biomass such as OCA shows promise in making the ash compositions viable for pulverised-fuel combustion

Multi-ancestry genome-wide association meta-analysis of Parkinson?s disease

Although over 90 independent risk variants have been identified for Parkinson’s disease using genome-wide association studies, most studies have been performed in just one population at a time. Here we performed a large-scale multi-ancestry meta-analysis of Parkinson’s disease with 49,049 cases, 18,785 proxy cases and 2,458,063 controls including individuals of European, East Asian, Latin American and African ancestry. In a meta-analysis, we identified 78 independent genome-wide significant loci, including 12 potentially novel loci (MTF2, PIK3CA, ADD1, SYBU, IRS2, USP8, PIGL, FASN, MYLK2, USP25, EP300 and PPP6R2) and fine-mapped 6 putative causal variants at 6 known PD loci. By combining our results with publicly available eQTL data, we identified 25 putative risk genes in these novel loci whose expression is associated with PD risk. This work lays the groundwork for future efforts aimed at identifying PD loci in non-European populations

Computational protein design enables a novel one-carbon assimilation pathway.

We describe a computationally designed enzyme, formolase (FLS), which catalyzes the carboligation of three one-carbon formaldehyde molecules into one three-carbon dihydroxyacetone molecule. The existence of FLS enables the design of a new carbon fixation pathway, the formolase pathway, consisting of a small number of thermodynamically favorable chemical transformations that convert formate into a three-carbon sugar in central metabolism. The formolase pathway is predicted to use carbon more efficiently and with less backward flux than any naturally occurring one-carbon assimilation pathway. When supplemented with enzymes carrying out the other steps in the pathway, FLS converts formate into dihydroxyacetone phosphate and other central metabolites in vitro. These results demonstrate how modern protein engineering and design tools can facilitate the construction of a completely new biosynthetic pathway

Computational protein design enables a novel one-carbon assimilation pathway.

We describe a computationally designed enzyme, formolase (FLS), which catalyzes the carboligation of three one-carbon formaldehyde molecules into one three-carbon dihydroxyacetone molecule. The existence of FLS enables the design of a new carbon fixation pathway, the formolase pathway, consisting of a small number of thermodynamically favorable chemical transformations that convert formate into a three-carbon sugar in central metabolism. The formolase pathway is predicted to use carbon more efficiently and with less backward flux than any naturally occurring one-carbon assimilation pathway. When supplemented with enzymes carrying out the other steps in the pathway, FLS converts formate into dihydroxyacetone phosphate and other central metabolites in vitro. These results demonstrate how modern protein engineering and design tools can facilitate the construction of a completely new biosynthetic pathway