Thesis (Ph.D.)--York University, 2005. Graduate Programme in Earth and Space Science. / Typescript. Includes bibliographical references (leaves 186-196). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11559

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 30, 2007). Includes bibliographical references (p. 165-174).

Thesis (Ph. D.)--Ohio State University, 1933. / Type-written. Includes bibliographical references (leaves [164]-166). Available online via OhioLINK's ETD Center

Deep-sea systems are understudied compared to any other ecological system on Earth, but they are important for ecosystem functioning and services. The deep sea is important in the climatic regulation of Earth, and it is a new frontier for resource provisioning for humanity. Impacts, such as increased carbon emissions and deep-sea fishing and mining will likely influence the system, but these effects are not well understood. To recognise these impacts, common patterns in community structure need to be understood. This study aims to assess community structure in the deep sea by looking at patterns in body size and biodiversity. It uses polychaetes (bristle worms) as a study group as they are the most abundant group in the benthic macrofauna in terms of density and play key roles in the food web. Body size is an important component of the community structure, as body size is correlated with many other traits of the organism, from physiological rates (e.g. heart or breathing rates) to population dynamics (e.g. production rates or population abundances) and species richness. It is thought that body size of deep-sea (endo)benthic organisms declines with increasing depth, which is often related to food availability which itself declines with increasing depth. Many contradictory results on body-size change with increasing depth, however, have been reported, including no change, increasing, or a parabolic relationship. It is demonstrated here (Chapter 2) that there is much variety in body-size estimates between different geographic regions and taxonomic groups. These differences can ultimately influence the predictions of other traits, and might hint at what might happen in changing climatic conditions. It sets the basis to argue that there should be a focus on explaining why there are differences, instead of focusing on finding a general trend for organisms in all geographical regions. Furthermore, it is unlikely that food availability alone can explain a change in body size. An alternative explanation is offered (Chapter 3), where habitat complexity is shown to influence body size. Sponge density, in the form of habitat complexity, can have a structuring effect on the community potentially through the loss of spicules that add complexity to soft-sediments, and this in turn can influence body size of organisms. Deep-sea community structure in terms of family richness has been studied at local spatial scale. Fewer studies have been performed on regional spatial scale and these studies lack extensive sampling coverage of environmental gradients. Here (Chapter 4), the first study is presented on the maintenance of deep-sea family composition on regional scale with high sampling coverage along a variety of environmental gradients. It is shown that energy (food) availability, habitat complexity, and long-term temperature are important in influencing the polychaete distribution in this region. It is shown that there is an unusual high proportion of an opportunistic group, the Capitellidae, present in the study area. Biodiversity is important for the maintenance of ecosystem functioning, but human impacts result in the restructuring of biodiversity. The first deep-sea biodiversity - ecosystem functioning relationship for macrofauna is presented (Chapter 5). It is shown that there is a positive and saturating relationship between biodiversity and ecosystem functioning. However, fishing intensity seems to influence this relationship by potentially affecting secondary biomass production, abundance and taxonomic and functional diversity measures. It is suggested that as the disturbance of fishing negatively impacts taxonomic and functional evenness, a system is created where opportunistic species are dominant, like communities found in disturbed areas such as under fish farms. This will have consequences for the state of the system and energy transfer to trophic levels higher up.

abstract: There have been many studies on the dynamics of infectious diseases considering the age structure of the population. This study analyzes the dynamics when the population is stratified by size. This kind of models are useful in the spread of a disease in fisheries where size matters, for microorganism populations or even human diseases that are driven by weight. A simple size structured SIR model is introduced for which a threshold condition, R0, equilibria and stability are established in special cases. Hethcote's approach is used to derive, from first principles, a parallel ODE size-structure system involving n-size classes.The specific case of n = 2 is partially analyzed. Constant effort harvesting is added to this model with the purpose of exploring the role of controls and harvesting. Different harvesting policies are proposed and analyzed through simulations. / Dissertation/Thesis / Ph.D. Applied Mathematics for the Life and Social Sciences 2012

<i>Leptophyes punctatissima</i> is unusual in that both sexes call. The male calls, the female replies and the male performs phonotaxis to the stationary female. Consequently mate choice could occur at either of two stages: first, during the interchange of calls and second, on the basis of proximate criteria once the male has approached. There is no evidence that females choose their mates on the basis of calling behaviour or call characteristics, though males that call more may achieve more matings. There is no evidence that body asymmetry has any effect on mating success for either sex. Males on a protein-supplemented diet do not produce larger spermatophores than males whose diet is not supplemented, but they do mate more often, possibly as a result of female choice but more likely because diet affects the rate at which males can produce spermatophores. Unsupplemented females mate more often than supplemented females, possibly as a result of male male choice or because they are seeking matings so that they can supplement their diet with spermatophores. Males give larger spermatophores to unsupplemented females. Larger males produce larger spermatophores. They also mate more often than smaller males, possibly as a consequence of female choice, success in male-male contests, or because larger males have larger energy reserves and can produce spermatophores more quickly. Larger females mate more often than smaller females but only when their diet was supplemented. Females lay more eggs the more times they mate. Females lay heavier eggs after their first mating than they do in later batches, and unsupplemented females lay more eggs after their first mating than supplemented females do, but otherwise female size, diet or level of asymmetry has no effect on the size or weight of eggs, or the number of eggs laid. The total weight of spermatophores females receive does not affect any measure of female reproductive success: neither fecundity, egg size or egg weight is affected by the weight of spermatophores females consume, irrespective of the diet the females were maintained on. Diet, size or number of matings does not affect female longevity.

ix, 84 leaves : ill. ; 29 cm Notes Typescript Thesis (M.S.)--University of Oregon, 2003 Includes vita and abstract Includes bibliographical references (leaves 73-84) Another copy on microfilm is located in Archives

Branching in poly(methyl methacrylate) (PMMA) is produced by incorporating a pre-prepared polymeric chain transfer agent (PCTA) into a single stage radical polymerisation. Samples of PCTA having a range of transfer functionalities and molar masses were synthesised by modifying a methacrylate-based copolymer. Control of branching in PMMA has been studied as a function of transfer functionality and molar mass in the PCT A and a function of MMA and initiator concentrations in the MMA polymerisation. The branched samples of PMMA have been characterised by size exclusion chromatography (SEC) with multi-detectors to determine Mark–Houwink and other parameters to assess levels of branching. Some PCTA samples have been prepared with a UV chromophore to facilitate characterisation by SEC-UV.

abstract: This paper examines the link between firm size and innovation. Given that innovation is highly reliant on human capital, the ability to attract, motivate, and retain high quality inventors is a key determinant of firm innovation. Firm size may affect these abilities, and small firms are known to account for a disproportionate share of aggregate innovation. I therefore investigate the role that sorting of inventors across firms plays in explaining this disparity. Talented inventors may find employment at a large firm less attractive due to the relative absence of growth options and a lower ability to link compensation to performance. Using inventor-level patent data, I construct employment histories for inventors at U.S. public firms. I find that the most productive inventors are disproportionately likely to move to small firms, while the least productive inventors disproportionately remain at large firms. These results cannot be explained fully by small firms' superior growth opportunities. In addition, productive innovators' turnover in small firms is sensitive to the level of option compensation. Taken together, this evidence is consistent with inventor sorting explaining part of the firm size innovation gap. / Dissertation/Thesis / Doctoral Dissertation Business Administration 2016

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