The analysis of microstructural shapes is an underutilized tool in the field of materials science. Typical observations of morphology are qualitative, rather than quantitative, which prevents the identification of relationships between shape and the mechanical properties of a material. Recent advances in the fields of computer vision and high-dimensional analysis have made computer-based shape characterization feasible on a variety of materials. In this work, the relationship between microstructural shapes, and the properties and function of the material as a whole, is explored using moment invariants as global shape descriptors. A diifferent relationship is examined in each of three material systems: how the three-dimensional shapes of cells in the cotyledons of the plant Arabidopsis Thaliana can be used to identify cell function; the two-dimensional shapes of additive manufacturing feedstock powder and the ability to distinguish between images of powders from different samples; and the two-dimensional shapes of ' precipitates and their influence on the creep resistance of single crystal nickel-base superalloys. In the case of Arabidopsis Thaliana cotyledon cells, three-dimensional Zernike and Cartesian moment invariants were used to quantify morphology, and combined with size and orientation information. These feature sets were then analyzed using unsupervised and supervised machine learning methods. Moderate success was found using unsupervised methods, indicating that natural delineations in the data correlate to cell roles to some degree. Using supervised methods, a success rate of 90% was possible, indicating that these features can be used to identify cell function. The ability of two-dimensional Cartesian moment invariants to distinguish meaningful features in particles of additive manufacturing feedstock was tested by using these features to classify images of feedstock. Ultimately, simple histogram matching methods were unsuccessful, likely because they rely on the most common particles to draw conclusions. A bag-of-words method was used, which uses high-dimensional visualization and clustering techniques to classify individual particles by common features. Histograms of particle clusters are then used to represent each image. This method was far more successful, and a correct classification rate of up to 90% was found, and comparable rates were discovered using invariants which describe the shapes only broadly. This indicates that moment invariants are an effective measure of the morphologies of these types of particles, and can be used to classify powder shapes, which control many properties which are relevant to the additive manufacturing process. In the case of the superalloys, it has been shown that the shape distribution of ' precipitates can be tracked using second order moment invariants. In addition, several loworder moment invariants are shown to correlate to creep resistance in four alloys examined, which supports the idea that the shape of precipitates plays role in determining creep resistance in these alloys.

The Diploma Thesis "Morphological defectiveness as a problem in teaching Russian as a mother tongue and a foreign language" occupies with the cases of explicitly codified defectiveness in morphological system of standard Russian. The chapter on verbs describes the issue of defectiveness paradigm in the 1st person singular in a certain group of verbs. It also includes the illustrations of such defectiveness forms from the internet forums and references about the problem both from prescriptively grammars and studying materials intended for native speakers and students of Russian as a foreign language. The chapter on nouns occupies with broken paradigm of nouns in genitive plural. This problem is taken from the historical perspective and again it contains the examples from the internet forums, codified grammar books and individual books. The chapter on participles examines the formation of active participles of the future tense which are codified as no normative but also illustrations from the literature of the past centuries and present, which can be found on the internet forums, show us that the problem is quite topical. The outcomes of the questionnaire investigation are summarised in an individual chapter, in the process the attention is focused on three main topics which were concentrated on in...

The taxonomic concept of the algal genus Mallomonas (Synurales, Synurophyceae) was based on an extraordinary morphological diversity of their siliceous scales. The main aims of this study were elucidation of phylogenetic relationships among its representatives and reconstruction of shape evolution of particular siliceous structures of their scales. Molecular data for six species were acquired for the first time, enabling a successful assessment of their phylogenetic relationships with the other representatives of the genus. On the basis of molecular data, the genus Mallomonas can be divided in two evolutionary lineages and this division is also reflected morphologically (with only a few exceptions) through presence or absence of a V-rib structure. Fine ornamentation of siliceous scales is species-specific and interestingly, the overall differences in morphology of siliceous scales are mostly reflecting phylogenetic relationships among representatives of the genus. In this context, morphological species concept of Mallomonas seems to be justified. Morphologically-based sections of the genus are often paraphyletic, because small sections (frequently containing only single species) tend to be nested within particular larger sections. The main reason for this discrepancy is accelerated morphological...

Language models play an important role in many natural language processing tasks. In this thesis, we focus on language models built on artificial neural net- works. We examine the possibilities of using morphological annotations in these models. We propose a neural network architecture for a language model that explicitly makes use of morphological annotation of the input sentence: instead of word forms it processes lemmata and morphological tags. Both the baseline and the proposed method are evaluated on their own by perplexity, and also in the context of machine translation by the means of automatic translation quality evaluation. While in isolation the proposed model significantly outperforms the baseline, there is no apparent gain in machine translation. 1

The interactions between engineering materials and their environment which give rise to stress corrosion cracking are reviewed and industrial examples from the petrochemical industry are described. In one of the examples, cracking took place in carbon steel exposed to pressurised gas containing carbon monoxide, carbon dioxide and water. The crack morphology in this system was studied by metallography of samples from industrial gas processing plants and the crack growth rates were determined using precracked specimens. Constant extension rate tests, U-bend specimens and potentiodynamic studies were used to evaluate alternative materials and inhibitor additions in CO-C02-H20 environments. Electrochemical noise was accessed as a technique to monitor sec on line. It was found that the CO-C02-H20 system was characterised by a time dependent adsorption of carbon monoxide at anodic and cathodic sites. The adsorption produced a critical balance between crack tip corrosion rate and the repassivation process comparable to the behaviour at the active-passive transition zone in more conventional systems. The anodic passivation exhibited a breakdown potential near to -400 mV (Ag/ AgCI) that defined the zone of sec susceptibility. Inhibition by CO and hence sec was virtually independent of CO partial pressure provided there was a sufficient reservoir of CO. The addition of commercial film forming inhibitors did not greatly influence the system and sec was still observed in CO-C02-H20 environments to which inhibitors had been added. Steels containing alloy additions of more than 9 % chromium were found to be resistant to sec but austenitic-ferritic weld joints cracked. A low alloy 3% nickel steel performed well in the constant extension rate tests but was not wholly resistant to sec. The morphology of stress corrosion cracks in CO-C02-H20 mixtures was influenced by carbon monoxide partial pressure. More corrosion was observed on the crack walls at low carbon monoxide partial pressure and widened cracks resembling •mesa• corrosion were common. This increased corrosion was probably due to difficulty in maintaining passivity in the crevice formed by the growing crack. Similarly, crevicing in precracked specimens appeared to inhibit sec and no crack extension was observed. Electrochemical noise proved to be a useful tool for monitoring. / Thesis (PhD)--University of Pretoria, 1994. / gm2013 / Materials Science and Metallurgical Engineering / PhD

Phonological and morphological awareness are shown to be predictors of hearing and deaf children's literacy achievements in various languages, and Arabic is assumed to be no different. However, this might not be the case for two reasons. Firstly, the linguistic context of the Arab world is characterised by diglossia, i.e. the use of two different varieties of the same language in different settings. Hearing and orally educated deaf children will therefore encounter the vernacular variety of Arabic outside school, but are introduced to literacy in the more prestigious variety of Standard Arabic during instruction in school. Secondly, Arabic orthography has two forms: a fully vowelised script, which is typically taught in the first two years of school, and a non-vowelised script, which is the form of the written language widely used in society. This study specifically aims to investigate whether phonological and morphological awareness are independent predictors of the emergent literacy achievement of hearing and orally educated deaf Kuwaiti children. This is in addition to the question of whether children's awareness of the two language forms, i.e. their dialect awareness, contributes to their literacy achievement and to their levels of phonological and morphological awareness. This investigation was carried out longitudinally through a number of phonological, morphological and dialect awareness measures utilised as predictors of literacy outcome skills of word reading, word spelling, pseudo-word decoding and reading comprehension. Variances of age and general cognitive ability were controlled for throughout all the analyses undertaken. The results for the first target group of hearing children (N = 78, aged 6; 2 years) indicated a significant superiority of phonological awareness as the predominant predictor of all literacy skills across grade levels one and two. Morphological awareness was a predictor of first- graders' spelling ability, and was subsequently implemented to predict all the literacy skills of second-graders. Dialect awareness was a predictor of the word reading and reading comprehension ability only for second-graders, and its mediational effect was revealed when it was seen to significantly reduce the effect of phonological and morphological awareness on second-graders' reading skills after being examined as a control measure. The results for the second target group of orally educated deaf children (N = 34, aged 7; 6 years) indicated that phonological, morphological and dialect awareness were varyingly significant independent predictors of the subjects' literacy skills. A mediational effect of dialect awareness on the predictive link between morphological awareness and word spelling outcome was also evident. Although the prediction association between literacy predictor and outcome measures was mostly consistent and similar across both groups, exceptions in the predictive pattern revealed that the deaf children were at a disadvantage in developing language awareness skills that facilitate efficient mapping of speech into the written form. These findings are discussed in terms of language-general and language-specific properties. The outcomes offered by the current study cannot imply a cause-and-effect association, but allow for constructive identification of literacy predictors and assist in clarifying possible implications for children's literacy capabilities. As the strengths and needs of the examined groups have been clearly recognised, future investigations of causal and mediational analyses will validate the current findings about the Arabic diglossic phenomenon, and additionally specify an appropriate response in terms of practical educational plans.

Master of Science / Department of Biology / David C. Hartnett / Herbivory is one of the major biotic interactions shaping the structure and dynamics of grassland plant populations and community structure. The two major grass growth forms, rhizomatous and caespitose species, may show different grazing tolerance and short-term overcompensation may offset long-term reductions in plant performance and fitness. The objectives of this study were to assess 1) the effects of long-term ungulate grazing on plant architecture, population structure, and life history traits of the caespitose perennial grass, Schizachyrium scoparium (little bluestem), and the rhizomatous Bouteloua curtipendula (sideoats grama) in tallgrass prairie, and 2) the effects of grazing intensity (frequency of defoliation) on growth responses of little bluestem. Long-term bison grazing decreased the cover, frequency, tiller height, and proportion of tillers producing seed in little bluestem, but caused no changes in tiller density and total genet size. Grazed little bluestem plants maintained a significantly larger below ground bud bank. Bison grazing had no long-term effect on the abundance, bud bank densities, or rhizome growth of the rhizomatous side-oats grama grass. Biomass, tiller density, relative growth rates, and proportion of tillers flowering in little bluestem all decreased with increasing frequency of defoliation. However, even an intense grazing regime (9 defoliations over a 12 month period) caused no plant mortality and no changes in new tiller emergence rates, or bud bank densities. Increasing defoliation frequency did result in shifts in plant architecture, as an increasing proportion of extravaginal tillers led to a more lateral, decumbent growth form. These results show that the rhizomatous side-oats grama grass has a significantly higher grazing tolerance than does little bluestem, and/or that bison selectively graze little bluestem. Results from responses to the experimental defoliation regimes suggest that little bluestem shows lower tolerance to high frequency of defoliation, and its maintenance of a reserve below ground bud bank may be its primary tolerance mechanism, allowing tiller populations to recover following severe defoliation.

A synopsis of the southern African members of the genera Dicoma Cass. and Macledium Cass. (family Asteraceae, subfamily Cichorioidiae, tribe Mutiseae, subtribe Gochnatiinae) is presented. The most recent monograph of Dicoma was done by Wilson (1923). It included 34 species, of which 17 are southern African, The southern African species were last treated by Harvey (1865). Traditionally Dicoma included 50 to 65 species, of which 23 occur in southern Africa. Ortiz (2001) reinstated the genus Macledium Cass., which was first described by Cassini (1825), following a phylogenetic study of Dicoma and related genera (Ortiz, 2000). The species previously belonging to sections Macledium and Pterocoma of the genus Dicoma have been transferred to the genus Macledium by Ortiz (2001). In this study, characters relating to morphology of the involucral bracts, disc floret cuticle ornamentation, type of pappus and the type of achenes are used to distinguish the two genera. Differences were found between the grassland species and Cape species of Macledium. Type of florets in the capitulum and pappus morphology are used to distinguish sections within Dicoma sensu stricto. Characters such as habit, leaf morphology, shape and size of the capitulum, involucral bracts vestiture and details of the pappus could be reliably used to distinguish species. The genus Dicoma now consists of about 35 species, of which16 species and two subspecies occur in southern Africa. Four informal groups of D. anomala subsp. anomala, two of D. anomala subsp. gerrardii as well as two of D. montana are recognized to accommodate infraspecific variation. Macledium comprises about 20 species, of which seven species, three subspecies and three varieties occurr in this region. M. spinosum is divided into two informal forms and a new combination, Macledium zeyheri subsp. zeyheri var. thyrsiflorum, is made. In view of the above, a comprehensive taxonomic revision of all the southern African taxa was done. Morphological and anatomical data were used to investigate relationships among the species of Dicoma sensu stricto, using the genus Macledium as the sister group. A phylogenetic analysis of Macledium was also done to investigate relationships between the grassland species and the Cape species. The taxonomic treatment includes the nomenclature, synonymy, diagnostic characters, uses, common names (where possible) and geographical distribution for all southern African taxa belonging to the two genera. Keys to the genera, sections, species and subspecies are provided and the diagnostic characters of the two genera are illustrated. / Prof. B.E. van Wyk

The neural basis of statistical learning as it occurs over time was explored with stimuli drawn from a natural language (Russian nouns). The input reflected the "rules" for marking categories of gendered nouns, without making participants explicitly aware of the nature of what they were to learn. Participants were scanned while listening to a series of gender-marked nouns during four sequential scans, and were tested for their learning immediately after each scan. Although participants were not told the nature of the learning task, they exhibited learning after their initial exposure to the stimuli. Independent component analysis of the brain data revealed five task- related sub- networks. Unlike prior statistical learning studies of word segmentation, this morphological learning task robustly activated the inferior frontal gyrus during the learning period. This region was represented in multiple independent components, suggesting it functions as a network hub for this type of learning. Moreover, the results suggest that subnetworks activated by statistical learning are driven by the nature of the input, rather than reflecting a general statistical learning system.

Gravel beaches and barriers occur on many high-latitude, wave-dominated coasts across the world. Due to their natural ability to dissipate large amounts of wave energy, gravel coasts are widely regarded as an effective and sustainable form of coastal defence. However, during extreme events waves may overtop, overwash, and even lower, the crest of the gravel beach, flooding the hinterland. In the evaluation of the safety of gravel coasts against flooding, coastal managers currently rely on models that have been shown in previous studies to be inaccurate. The research in this thesis attempts to improve the current predictive capacity of gravel beach storm response by developing a new process-based model to simulate storm impacts on gravel coasts. The numerical model developed in this thesis, called XBeach-G, is a morphodynamic, depth-averaged, cross-shore profile model, based on the XBeach model for sandy coasts (Roelvink et al., 2009). The model simulates the morphological response of gravel beaches and barriers to storms by solving: (1) intra-wave flow and surface elevation variations using a non-hydrostatic extension of the non-linear shallow water equations; (2) groundwater processes, including infiltration and exfiltration, using a Darcy-Forchheimer-type model; and (3) bed load transport of gravel using a modification of the Van Rijn (2007a) bed load transport equation to include flow acceleration effects, which are shown to be significant on coarse-grained beaches. The model is extensively validated for hydrodynamics, groundwater dynamics and morphodynamics using detailed data collected in physical model experiments, as well as data collected in the field on four natural gravel beaches in the UK and one in France. Validation results show that the model has high quantitative skill in simulating observed hydrodynamics on gravel beaches across a wide range of forcing conditions, in particular with regard to wave transformation, wave run-up and wave overtopping. Spatial and temporal variations in groundwater head are shown to be well represented in the model through comparison to data recorded in a physical model experiment. Validation of the morphodynamic component of XBeach-G shows that the model has high model skill (median BSS 0.75) in simulating storm impacts on five gravel beaches during ten storm events, with observed morphodynamic response ranging from berm-building to barrier rollover. The model is used to investigate hydrodynamic processes on gravel beaches during storms, where it is found that incident-band variance is elemental in the generation of wave run-up on gravel beaches. Furthermore, simulations of wave run-up during high-energy wave events show a distinct disparity between run-up predicted by empirical relations based on the Iribarren parameter and wave steepness, and run-up predicted by XBeach-G, where predictions by the empirical relations substantially underestimate observed wave run-up. Groundwater processes are shown, by means of sensitivity simulations, to strongly affect the morphodynamic response of gravel beaches and barriers to storms. The research in this thesis supports the hypothesis that infiltration in the swash is a key driver for the berm-building response of gravel beaches and helps to reduce erosion of the upper beach during storms. Through model simulations on a schematic gravel barrier it is shown that groundwater processes effectively increases the capacity of gravel barriers to withstand storms with 1-3 m higher surge levels than if groundwater processes did not occur. Reducing the width of a barrier leads to a lowering of this capacity, thereby reducing the resilience of the barrier to extreme storm events. Despite its strong influence on gravel beach morphodynamics, it is found that infiltration plays a relatively small role on wave run-up levels on most natural gravel beaches (median R 2% run-up level reduction of 8%). Application of the model in validation simulations and sensitivity simulations in this thesis, as well as in storm hindcast simulations discussed by McCall et al. (2013) shows the value of using the process-based XBeach-G model in coastal flooding analysis over the use of empirical tools. While no model can be considered entirely accurate, application of XBeach-G in all hindcast overwash simulations has lead to reasonable estimates of overtopping discharge and of morphological change, which is a significant improvement over the frequently substantial errors of the empirical tool designed for this purpose.