<p><font face="TimesNewRomanPSMT"> <p align="left">Natural radioactivity studies have been carried out to study the textural characteristics, heavy mineral composition, provenance, sediment transport, and depositional environment of beach placer deposits. The naturally occurring radionuclides such as properties of beach sands, which reflect the geological characteristics such as transport and sorting processes and the depositional environment. The present work focuses on the radiometric characteristics of beach sand deposits along the west coastof South Africa. Beach sands samples were collected at the Melkbosstrand (MBS) and Ouskip (OSK) beach. The activity concentrations of these radionuclides were determined by high-resolution gamma-ray spectrometry using a high-purity germanium (HPGe) detector in a low-background configuration.</p> </font></p>

Nitrogen is an essential building block of proteins and nucleic acids and, therefore, crucial for the biosphere. Nearly 79 % of the air consists of nitrogen, but in the form of nitrogen gas (N2), which cannot be utilized by most organisms. Nitrogen-fixing microorganisms such as cyanobacteria have a central role in supplying biologically useful nitrogen to the biosphere. Therefore, it is important to achieve further understanding of control mechanisms involved in nitrogen fixation and related processes. This thesis concerns different molecular aspects of the transcription factor NtcA from the heterocystous cyanobacterium Anabaena PCC 7120. Apart from performing oxygenic photosynthesis, Anabaena PCC 7120 is also capable of fixing nitrogen. NtcA is a protein regulating transcription of a wide range of genes and in particular genes involved in cyanobacterial global nitrogen control. NtcA binds as a dimer to the promoter regions of target genes such as those involved in nitrogen fixation and heterocyst differentiation. NtcA from Anabaena PCC 7120 was heterologously expressed in E. coli and a high yield of recombinant protein was achieved through purification by Ni-IMAC chromatography. The purified NtcA was used to examine DNA binding motifs preferred by NtcA in vitro using a semi-random library of DNA sequences. The preferred binding sequence for NtcA is TGTA – N8 – TACA and at least five of the bases in the palindromic binding site are necessary for binding. Differences in the consensus sequence in vivo may reflect variations in the structural conformation of NtcA under various physiological conditions. Since an earlier study suggested redox-regulated NtcA-DNA binding the role of the two cysteine residues of NtcA were investigated. Binding studies using three mutants, Cys157Ala, Cys164Ala, and Cys157Ala / Cys164Ala, demonstrated that all these NtcA variants bind to DNA with a slightly higher affinity in the presence of the reducing agent DTT. The studies indicate that the binding mechanism is not dependent on a conformational change of NtcA caused by breaking of intra-molecular disulfide bonds. Crystallization followed by structural studies rendered a partial crystal structure of NtcA. The structure verifies that NtcA is a dimeric protein. Each subunit has three domains: the N-terminal domain, a dimerization helix connecting the N-terminal domain with the C-terminal domain, as well as making up the dimer interface, and a C-terminal domain including the DNA binding helix-turn-helix motif. Furthermore, an NtcA binding site was found in the promoter region of the hupSL gene, encoding an uptake hydrogenase in Nostoc punctiforme (ATCC 29133), indicating that yet another gene is transcriptionally controlled by NtcA, thereby further emphasizing the multifaceted role of NtcA in cyanobacteria.

Conceptual design is a series of complex cognitive processing tasks and research seeking to further understand design cognition will benefit by considering literature from the field of psychology. This thesis presents two research projects, which sought to understand and mitigate design biases in conceptual design through the application of theories from biological and cognitive psychology. The first of these puts forward a novel model of design creativity based on connectionist theory and a neurological phenomenon known as long-term potentiation. This model is applied to provide new insights into design fixation and develop interventions to assist designers overcome fixation. The second project seeks to establish that cognitive heuristics and biases predictably influence design cognition. Two studies are discussed that examined the role of confirmation bias in design. The first establishes that confirmation bias is present during concept generation; the second demonstrates that decision matrices can mitigate confirmation bias in concept evaluation.

Conceptual design is a series of complex cognitive processing tasks and research seeking to further understand design cognition will benefit by considering literature from the field of psychology. This thesis presents two research projects, which sought to understand and mitigate design biases in conceptual design through the application of theories from biological and cognitive psychology. The first of these puts forward a novel model of design creativity based on connectionist theory and a neurological phenomenon known as long-term potentiation. This model is applied to provide new insights into design fixation and develop interventions to assist designers overcome fixation. The second project seeks to establish that cognitive heuristics and biases predictably influence design cognition. Two studies are discussed that examined the role of confirmation bias in design. The first establishes that confirmation bias is present during concept generation; the second demonstrates that decision matrices can mitigate confirmation bias in concept evaluation.

À l'aube du troisième millénaire, face aux crises écologiques et à l'intensification des inégalités sociales et économiques, les êtres humains sont appelés à redéfinir leur rapport entre l'économie, la société et la biosphère. La prise en compte des dimensions sociale et écologique dans les activités de production, de consommation et de gestion des activités économiques devient donc un enjeu majeur pour l'ensemble des acteurs concernés et des territoires. Certains d'entre eux valorisent un nouveau mode de développement. Ce dernier est fondé sur des principes de solidarité, de démocratie, d'écologisme, de durabilité, d'ancrage local et d'innovation socioterritoriale. Ainsi, l'émergence de pratiques solidaires et écologiques appelle notre curiosité scientifique et notre perspective pragmatique dans le but d'y extraire des ingrédients qui pourront avoir une certaine utilité sociale, soit pour les praticiens ou les chercheurs. Au Québec, le mouvement de l'économie sociale a le potentiel de porter ce projet de renouvellement des pratiques économiques en vue d'une perspective écologique et solidaire. Ce mémoire présente deux initiatives locales d'économie sociale qui intègrent la dimension écologique au sein de leurs activités. La première, les Services horticoles, Les Pousses urbaines, œuvre dans le secteur de l'environnement (horticulture écologique), et la deuxième, la Société de développement Angus, est un promoteur immobilier à vocation communautaire qui intègre des objectifs écologiques. Ces deux entreprises sont situées dans l'arrondissement Rosemont-La Petite-Patrie, un territoire fécond en matière d'expériences de développement durable. L'objectif de cette recherche est d'examiner les processus par lesquels les initiatives locales d'économie sociale arrivent à concilier les objectifs sociaux, économiques et écologiques qu'elles se sont donnés. Notre démarche de recherche permet de passer en revue les conditions et les moyens qui facilitent la conciliation des objectifs mentionnés, de situer le degré de durabilité des objectifs en fonction de deux groupes d'initiatives du secteur environnemental ou d'un autre secteur de l'économie sociale et, enfin, d'identifier les irritants liés à une bonne intégration de la dimension écologique au sein des deux organisations étudiées. Notre démarche qualitative a été orientée par trois approches théoriques : le développement durable, l'économie sociale et solidaire, et le développement local. Leur articulation a généré des grilles d'analyse qui nous ont permis de tirer des conclusions qui mettent au défi l'ensemble des acteurs, notamment ceux politiques et institutionnels. Il appert que l'État a un rôle majeur à jouer sur le plan du soutien aux missions sociale et écologique des entreprises et de la régulation d'un marché qui externalise les coûts sociaux et environnementaux. Enfin, un des défis majeurs des organisations d'économie sociale est leur capacité de créer de nouveaux arrangements organisationnels et institutionnels en vue d'un mieux vivre ensemble solidaire et écologique. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Économie sociale, Économie solidaire, Développement durable, Environnement, Pratiques écologiques, Pratiques solidaires, Développement local, Initiative locale, Montréal.

This report is product of a degree project accomplishment at Linnaeus University in Växjö, Sweden. It is about designing a testing rig for impact loading of beams for laboratory use. The specimens to be used were 1 meter long 8 standard profiles given in the project assignment. The first step in this project was to design and dimension a testing rig which is suitable for laboratory use. The height and the maximum mass were chosen according to laboratory use conditions and safety issues. The second step was designing the fixation for the test sample to the testing rig without any dislocation by the impact load. The third step was to measure the falling height of the mass onto the test sample and measure the deflection of the beam. In this case, the precision of falling height was not very important but measuring the deflection of the beam with the highest possible precision was most important. A measurement system is used considering this factor. The project started with the idea of affecting the impact loads on the standard steel construction beams. The aim of this project is to design an impact loading testing rig which can be used for the purpose of laboratory experiments and compare the real results from the experiments with the theoretical results from the calculations. In the project, Solid Works and AutoCAD software are often used both in the drawings and strength and stress analyses.

This work explores the possibilities of robust, noise adaptive and automatic segmentation of driver eye movements into comparable quantities as defined in the ISO 15007 and SAE J2396 standards for in-vehicle visual demand measurements. Driver eye movements have many potential applications, from the detection of driver distraction, drowsiness and mental workload, to the optimization of in-vehicle HMIs. This work focuses on SeeingMachines head and eye-tracking system SleepyHead (or FaceLAB), but is applicable to data from other similar eye-tracking systems. A robust and noise adaptive hybrid algorithm, based on two different change detection protocols and facts about eye-physiology, has been developed. The algorithm has been validated against data, video transcribed according to the ISO/SAE standards. This approach was highly successful, revealing correlations in the region of 0.999 between analysis types i.e. video transcription and the analysis developed in this work. Also, a real-time segmentation algorithm, with a unique initialization fefature, has been developed and validated based on the same approach. This work enables real-time in-vehicle systems, based on driver eye-movements, to be developed and tested in real driving conditions. Furthermore, it has augmented FaceLAB by providing a tool that can easily be used when analysis of eye movements are of interest e.g. HMI and ergonomics studies, analysis of warnings, driver workload estimation etc.

A study was conducted to determine (1) the N contribution of lentil (<i>Lens culinaris</i> Medikus) and its effect on subsequent wheat (<i>Triticum aestivum</i> L.) crops in the Dark Brown and Brown soil zones of Saskatchewan, (2) if synchronization of available N contributes to the rotation benefit, and (3) N fertilizer replacement value of the N effect of lentil on the subsequent wheat crop. Two approaches were used: a landscape-scale study established at Dinsmore in 1994, and a repeated small-plot study established at several locations (Dinsmore, 1993 and 1994; Clavet, Conquest, Eston and Zealandia, 1995). In the landscape-scale study, N2 fixation by lentil ranged from 28 to 46 kg ha-1, with an average of 34 kg ha -1 N and an N balance of -36 kg ha-1. In the small-plot study, N2 fixation ranged from 10 to 112 kg ha -1 with an average of 59 kg ha-1 N and an N balance of -22 kg ha-1. In the landscape-scale study, preseeding available N on the rotation that incorporated lentil was 29 and 61% higher than in the monocropped wheat in the first and second subsequent crops, respectively. The corresponding values for the small-plot study were 59 and 14%, respectively. N availability was well synchronized with the period of maximum N demand by the wheat crop in both rotations. However, both lentil-residue N and wheat-residue N were poorly synchronized with the period of maximum N demand by the wheat. The rotation effect was exhibited in higher grain yield (23% higher in the landscape-scale study, and 21% higher in the small-plot study). Approximately 10 and 70% of the rotation benefit in the landscape-scale and small plot studies, respectively, were attributed to the N effect. Nitrogen fertilizer replacement value ranged from 47 to 89 kg ha-1 N. Therefore, lentil can fix enough N and indirectly contribute to greater available N in subsequent crops than in crops following non-legumes. However, the actual amount of N derived from lentil residue is small. The greater available N is attributed to spared N and enhanced soil N mineralization. Hence, under the conditions of this study, enhancement of available N contributed more to the rotation benefit than synchronization. The high NFRV show that inclusion of lentil in the rotation can enhance available N in the cropping system and potentially reduce fertilizer N application.

Cartilage repair and/or replacement is necessary for many orthopaedic conditions including fissures from blunt trauma, autograft or allograft transplantation, and replacement of focal defects with biological or synthetic constructs. In cartilage repair, initial integration between the host tissue and repair site is desirable to allow for nutrient transport, molecular deposition to enhance fixation, and eventual stress transmission across the interface. It has been postulated that effective transport and crosslinking of newly synthesized collagen molecules across a repair site may be vital to the process of integrative repair, and recent experiments have correlated collagen deposition with the strength of such repair. Other investigations have shown that enzymatic degradation of the cartilage surface may enhance integrative repair and can increase bond strength of an adhesive to cartilage. This study explored a novel approach involving photochemical bonding of cartilage tissue samples through collagen crosslinking as a means to achieve rapid and effective initial fixation, with the goal of enhancing biological integration. Photosensitized collagen gels were first analyzed via FTIR to determine the crosslinking effects with respect to collagen type and photochemical mechanism. Using the photogellation FTIR results as a parametric guide, in vitro mechanical testing of photochemically bonded meniscal fibrocartilage and hyaline articular cartilage tissues was performed using a modified single-lap shear test. Finally, the cellular viability and bond stability of a photochemically bonded cartilage interface was evaluated over seven days of in vitro culture, where the bond strength was assessed by pushout of cores from annular defects. Results of this study have demonstrated the potential of combining enzymatic surface modification with photodynamic techniques to directly bond cartilage tissues for initial fixation.

Plant growth-promoting bacteria (PGPB) have been studied in many agriculturally interesting plants, but never in pitcher plants. Sarracenia oreophila (the green pitcher plant) is an endangered species in Georgia, Alabama, and North Carolina (Rice 2010). With the help of Dr. Jim Spain's lab, a previous student in Dr. Gerald Pullman's lab discovered evidence that nitrogen-fixing bacteria (Burkholderia spp.) live within these pitcher plants. This study aims to determine whether these nitrogen-fixing bacteria confer a benefit to their host plants by providing fixed nitrogen. To do this, pitcher plants were inoculated with the Burkholderia and grown on a control medium, a medium without sugar (as the sugar causes the bacteria to grow until they hinder the plants), various media that are missing nitrogen-containing compounds usually provided in growth media, and a medium completely lacking nitrogen. These plants were compared to control plants on the same media that had not been inoculated with Burkholderia. The plants' biomass and root growth were measured. The data suggest that Burkholderia may stimulate plant biomass growth when sufficient nitrogen is present and there may be a nitrogen-threshold that needs to be met in order to sustain the Burkholderia-Sarracenia symbiosis. Also, the Burkholderia has a negative effect on roots grown in high-nitrogen media, possibly due to competition for nutrients.