Around 70% of the world is covered with water but only 2.5% of it is freshwater and even less is available for the ecosystem and humanity. The limited available fresh water is facing increasing challenges from water pollutions and eutrophication is one of the major concerns worldwide. The reason of eutrophication is the presence of excessive amounts of phosphorus and nitrogen in water bodies, which may cause algal blooms and a variety of harms to aquatic ecosystem in association with algal blooms. Among these two components, phosphorus plays a major role in eutrophication control and recovery since atmospheric N2 can be fixed by biological nitrogen fixation (BNF) processes and is therefore of little meaning to control. In this study, we investigated for the first time the potential of using controlled growth of algae and, in particular, filamentous cyanobacterium Spirulina platensis, for eutrophic water restoration. This study investigated the algal cell growth, algal by-product production, and removal of phosphate by S. platensis at different phosphate levels in artificial wastewaters and eutrophic waters. Results indicate that S. platensis could remove 90.17% of phosphorus from artificial wastewaters containing 10 mg/L phosphate in a 16-day cultivation period. When tested for eutrophic water restoration, S. platensis was able to convert hypo-eutrophic, eutrophic, and meso-eutrophic waters to oligotrophic water. It was shown that by using 100- micron nylon mesh cloth we could keep biomass concentration to be lower than 0.30±0.02 g/L. In the meantime, light/dark tests indicate that the dissolved oxygen level would not go below the hypoxic level, i.e., 4 mg/L after a 12-hour dark period at biomass concentration up to 1 g/L. These results indicate that it is possible to use S. platensis for both control of point source discharge and eutrophic water restoration.

Ecological restoration has the potential to stem the tide of habitat loss, fragmentation and transformation that are the main threats to global biological diversity and ecosystem services. Through this thesis, I aimed to evaluate the ecological consequences of a 33 year old rehabilitation programme for coastal dune forest conservation. The mining company Richards Bay Minerals (RBM) initiated what is now the longest running rehabilitation programme in South Africa in 1977. Management of the rehabilitation process is founded upon the principles of ecological succession after ameliorating the mine tailings to accelerate initial colonisation. Many factors may detract from the predictability of the ecological succession. For example, if historical contingency is a reality, then the goal of restoring a particular habitat to its former state may be unattainable as a number of alternative stable states can result from the order by which species establish. Succession appears to be a suitable conceptual basis (at this stage in regeneration at least) for the restoration of coastal dune forest. Patterns of community characteristics observed in rehabilitating coastal dune forest sites were similar to those predicted by ecological succession, with few exceptions. Changes in the species pool such as the establishment of strong dominants may lead to divergence of regenerating trajectories away from the desired endpoints. The species composition of herbaceous plants in regenerating coastal dune forest sites became increasingly uniform as the time since disturbance increased. Despite initially becoming more similar they II deviated away from an undisturbed reference site. Contrary to our expectations, non-native species did not contribute the most to dissimilarity. The deviation from the reference forest is attributable to the higher abundance of a native forest specialist in the reference site and the higher abundances of native woodland adapted species in the rehabilitating sites. Changes in the disturbance regime under which species have evolved may lead to arrested succession. The rehabilitation of coastal dune forest relies on the Acacia karroo successional pathway which, has been criticised because Acacia dominated woodlands may stagnate succession. The patterns of species composition within regenerating coastal dune forest are a response to the canopy characteristics and represent an early stage in forest succession. Succession did not appear to be stagnant. Ecological succession does not pay much heed to the role that the surrounding landscape composition can play in the assembly of communities. The theory of Island biogeography provides predictions about how landscape composition influences community assembly. Landscape spatial parameters, measuring edge, isolation, and area explained the patch occupancy of the several bird and tree species, however, responses to patch characteristics were varied and idiosyncratic. For restoration to succeed, managers need to consider the spatial configuration of the landscape to facilitate colonization of rehabilitating patches. From this thesis and previous work, it appears that processes are in place that will lead to the reassembly of dune forest communities. As the rehabilitating sites are at an early stage of regeneration this may take some time to give rise to these coastal dune forest communities, and the management of rehabilitating coastal dune forest must allow for this. In addition, it is III important to remember that time may be interacting with the landscapes spatial attributes, which may limit the presence of certain species. / Thesis (PhD)--University of Pretoria, 2011. / Zoology and Entomology / unrestricted

The boundaries between freshwater and terrestrial ecosystems can be areas of important subsidy transfers. These subsidies, such as leaf litter inputs to streams or aquatic emerging insects into riparian zones, link food webs and provide benefits to consumers in the form of nutrients and energy. Subsidies from aquatic systems tend to have high levels of essential long chain polyunsaturated fatty acids (LC-PUFAs), such as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) that are only produced by certain forms of aquatic algae. These LC-PUFAs are highly important in growth, development, and other metabolic functions across animal groups (Brett and Muller-Navarra 1997, Gladyshev et al. 2009).

Virgil's Georgics portray peace and war as disparate states derived from the same fundamental materials. Adopting a didactic tone, the poet uses the language of farming to confront questions about the making of lasting peace in the wake of the Roman civil wars. Rife with subjunctive constructions, the Georgics place no hope in the easily realized peace of a golden age; instead, they teach us that peace must be sowed, tended, reaped, and replanted, year after year. Despite this profound engagement with the consequences of civil war, however, the Georgics have not often been studied in relation to English writers working after the civil wars of the 1640s. I propose that we can better understand poems by Andrew Marvell, John Dryden, Anne Finch, and John Philips--all of whom grappled with the ramifications of war--by reading their work in relation to the georgic peace of Virgil's poem. In distinct ways, these poets question the dominant myth of a renewed golden age; instead, they model peace as a stable yet contingent condition constructed from chaotic materials, and therefore in need of perpetual maintenance. This project contributes to existing debates on genre, classical translation, the relationships between early modern poetry and politics, and most importantly, poetic representations of political and social peace. Recent work has argued for the georgic as a flexible mode rather than a formal genre, yet scholars remain primarily interested in its relation to questions of British national identity, agricultural reform movements, and the production of knowledge in the middle and later decades of the eighteenth century. I argue, however, for the relevance of the georgic to earlier poems written in response to the consequences of the English civil wars. The dissertation includes chapters devoted separately to Marvell, Finch, and Dryden, and concludes with a chapter on how their dynamic conceptions of georgic peace both inform and conflict with aspects of the popular eighteenth-century genre of imitative georgic poetry initiated by Philips and brought to its height by James Thomson. / 2017-05-01T00:00:00Z

This thesis explores potential seeding techiniques to limit harmful effects of preemergent herbicide on a seeded species while simultaneously reducing abudance of annual invasive grasses. The first chapter examines the use of activated carbon seed coatings and furrows to limit herbicide effect on seeds of a perrenial bunchgrass. We found that both carbon coatings and furrows mitigated some of the herbicide effects, but that only when the two techniques were combined did we observe unaffected seedling emergence, plant density, and aboveground growth. Therefore, we suggest to management that use of carbon coatings and furrows after herbicide application can likely be used to reduce invasive annual grasses while simultaneously establishing a native bunchgrass. In chapter 2, we examine the effects of a novel preemergent herbicide indaziflam, on native seeds and compare it against a common preemergent herbicide, imazapic. We found that indaziflam provides superior long-term control of annual invasive grasses than imazapic, but that it is also more detrimental to native seeds. Our results suggest that indaziflam is best suited for control purposes only, and is hard to incorporate in restoration seeding efforts due to its strong effects on native seed.

The purpose of this thesis is to develop a mathematical approach and associated software implementation for deconvolution of two-dimensional Transmission Electron Microscope (TEM) images. The focus is on TEM images of weakly scattering amorphous biological specimens that mainly produce phase contrast. The deconvolution is to remove the distortions introduced by the TEM detector that are modeled by the Modulation Transfer Function (MTF). The report tests deconvolution of the TEM detector MTF by Wiener _ltering and Tikhonov regularization on a range of simulated TEM images with varying degree of noise.The performance of the two deconvolution methods are quanti_ed by means of Figure of Merits (FOMs) and comparison in-between methods is based on statistical analysis of the FOMs.

No description available.

My dissertation examines the intersections of romance, religion, and politics in England between 1588 and 1688, reading across the divide between centuries to enable a fuller understanding of romance during the English Civil War and its aftermath. In the decades that witnessed Charles I's fall and his son's restoration, royalists and republicans alike found solace, and grounds for resistance, in romance's formal promise that suffering and disappointment would yield to the restoration of a story's true champions. Although historicist efforts to contextualize seventeenth-century romance have productively complicated the structuralist view of it as a basic archetype, such studies are fraught with their own simplifications: romance is often depicted as a continental trend briefly embraced by midcentury royalists, especially women. While a few scholars have noted the artificiality of some of these limits, we have yet to come to terms with seventeenth-century romance's long English tradition, its ability to penetrate other genres, and its hold over male and female writers and readers of diverse ideologies. To this end, my project traces two interwoven threads. First, I argue that the potent subjectivity offered by romance correlated with the widespread Protestant belief in divine election, inviting seventeenth-century subjects to locate themselves and their allies within a providentially protected community. Far from being a royalist fad, romance became a battleground between royalists and Puritan republicans: both sides denigrated their enemies' manipulation of the genre while tacitly or openly reclaiming it for themselves. Second, I consider how writers of romance contended with recurring problems of form, genre, and gender: due to the length of romantic plot and the related issue of multiple subjectivities, they found innovative ways to represent the friction between providential romance and national or personal tragedy, as well as the tension between gendered narrative perspectives. As England struggled to recuperate from its civil conflicts, writers also turned to romance not merely to represent elect community, but to reconstruct it, thinking critically about whether the genre might breach and repair the very perspectival divides in politics, religion, gender, and identity that it had been so instrumental in maintaining.

Mycorrhizae have been used in restoration for decades. However, studies assessing the use of mycorrhizae in Bromus tectorum-invaded areas of the Great Basin are limited. Two greenhouse pot experiments were conducted to assess the role of mycorrhizae in sagebrush restoration. The first objective (Chapter 2) was to determine the response of Pseudoroegneria spicatum, Elymus elymoides, and B. tectorum to mycorrhizal symbiosis by altering phosphorus, density, species, presence of mycorrhizae and water levels in a 5 factor design. To assess the mycorrhizal response, a variety of morphological and physiological traits were measured, such as tissue P concentration, specific root length, specific leaf area, carbon isotope discrimination, etc. The effects of the different treatment combinations were analyzed using ANOVA. The second objective (Chapter 3) was to determine the role of different inocula in competition between the three grasses. Species, density, and inoculum type were altered in a 3 factor design. Inoculum was cultured on Allium plants. The effect of locally cultured inoculum on the species was compared to the effect of commercial inoculum. The response of each species to mycorrhizae with different species compositions and densities was assessed. Morphological measurements were used to determine each species response to the different factor combinations. The effects of the different treatment combinations were analyzed using ANOVA. This research provides land managers with information regarding the efficacy of using local versus commercial inocula and whether they should use mycorrhizae in restoring their systems.

We investigated the effects of different fire restoration treatments on five shrubsteppe bird species in the Great Basin of central Utah. Sagebrush communities and the associated avifauna are under particular threat due to changing fire regimes. Although fires are locally destructive, it is hypothesized that they improve habitat by increasing landscape-level heterogeneity. As long as fire follows a historic fire regime, the plant and animal communities can usually recover. However, fires can and often do burn outside of the normal regime. The Milford Flat Fire, which occurred in west-central Utah, was the largest wildfire recorded in the Great Basin. Considered catastrophic, concern existed that natural recovery of sagebrush and its avifauna would be unlikely. To prevent this, vegetation reseeding treatments were applied immediately post-fire. These treatments included two seed mix types, with or without a shrub component, and three mechanical applications, drill seeding, aerial seeding followed by chaining, and aerial seeding only. We surveyed the avian community in the different treatment types and in untreated areas within the fire using line transect distance sampling methods. Using a space for time substitution, we sampled nearby unburned areas as reference to represent pre-fire conditions. We hypothesized that the treatment areas would be more similar to the reference than the untreated areas, and that the treatments would all have similar effects. We found some effect on the presence and extirpation of the birds at the guild and overall bird level. We found no significant effect from the treatments on the five study species at the species level, and no effects on bird densities. The effects of the restoration treatments were overshadowed by the effect of the fire on changing the habitat, namely, the density of sagebrush. We saw a pattern of birds responding to the removal or survival of sagebrush and the treatments were insufficient in affecting a short term response.