Insufficient research training contributes to the current shortage of researchers in the field of speech-language pathology and contributes to the dearth of multicultural and multilingual (MCML) research. There is limited information regarding how MCML issues are addressed in Research Methods courses in CSD. This research explores the extent to which MCML issues are included in CSD Research courses.Learner Outcome(s): Identify the importance of MCML in research method courses Describe ASHA MCML resources Describe strategizes to integrate MCML issues into coursework

L’haplodiploïdie chez les hyménoptères leur confère une meilleure résistance aux effets délétères de la dépression de consanguinité. Cependant, certains hyménoptères ont un déterminisme du sexe particulier qui les rend sensibles à cette dépression. Chez ces espèces, le genre des individus dépend de la complémentarité des allèles à un locus donné, le single-locus Complementary Sex Determination (sl-CSD). Les oeufs non fécondés se développent en mâles haploïdes alors hémizygotes au locus de CSD. En revanche les oeufs fécondés donnent des femelles diploïdes s’ils sont hétérozygotes au locus du CSD mais deviennent des mâles diploïdes s’ils sont homozygotes pour ce même locus. Ces derniers sont d’autant plus fréquents dans les populations consanguines où le taux d’homozygotes est élevé. Or, les mâles diploïdes sont dans la majorité des cas non viables ou stériles. La production de tels mâles est de ce fait coûteuse pour les femelles. La faible viabilité des mâles diploïdes s’apparente alors à de la dépression de consanguinité. Par des approches liées à l’écologie comportementale et à l’écologie chimique le projet de thèse se concentre sur l’étude des coûts individuels générés par la production de mâles diploïdes et à l’évolution des comportements sélectionnés en réponse à ces coûts. Dans un premier temps, je me suis intéressée à la fitness des mâles diploïdes et aux répercussions de leur production sur les femelles de la population. Dans un second temps, j’ai étudié les comportements permettant de réduire les coûts de la production des mâles diploïdes. Les individus apparentés représentent les partenaires sexuels où le risque de produire des fils diploïdes est le plus élevé. De ce fait, les comportements d’évitement de la consanguinité devraient être sélectionnés dans ces populations / Haplodiploidy in hymenopterans offers a great resistance to the deleterious effect of inbreeding depression. However, some hymenopterans have a specific sex determination which drives them to this depression. Among those species, the sex of individuals depends on allele complementary at a particular locus; the single-locus Complementary Sex Determinatation (sl-CSD). Unfertilized eggs give birth to haploid males which are hemizygotes at the CSD locus. Conversely, fertilized eggs develop into females when heterozygote at the CSD locus but become diploid males when homozygote at the same locus. Diploid males are especially frequent in inbred populations with a high inbreeding rate. Yet diploid males are generally unviable or sterile. Production of such males is therefore costly for females. Reduced viability of diploid males is then similar to inbreeding depression. Linked with behavioural ecology and chemical ecology approaches, the PhD project starts by focusing on individual costs due to production of diploid males, and then on behaviours that have evolved in response to these costs. As a first step, the fitness of diploid males and its impact on females of the population have been measured. If they are unviable, their production is akin to female mortality. As a second step, we studied behaviours that reduce the cost of diploid male production. Related individuals are sexual partners that are most likely to father diploid sons. Therefore, behavioural inbreeding avoidance may be selected in such populations

Heart dysfunction is a worldly widespread problem that currently is one of the leading causes of death. Studies indicate that many deaths related to cardiac dysfunction could have been prevented if discovered early. Contemporarily, ultrasound and electrocardiography are indispensable modalities for diagnostic purposes and analysis of cardiac function. The Ventricorder is an Ultra-Wideband radar sensor manufactured by the Norwegian company Novelda. Ventricorder has been shown to be able detect heart movements and breathing but its actual clinical value remains to be investigated. The Cardiac State Diagram (CSD) is a pre-clinical software tool for visualization of the heart's mechanical function. The CSD is confirmed by pilot studies to be able to constitute a basis for diagnosis and cardiac function assessment. Theoretically, the CSD is well suited to be used with the Ventricorder since the Ventricorder detects small changes over time and information about time events is all that is required for the creation of a CSD. Contemporarily, ultrasound tissue velocity imaging (TVI) is usually used for production of CSDs and in this master thesis we examined if the Ventricorder can be used to produce CSDs. This was done by mainly comparing velocity data from the Ventricorder with velocity data from temporally synchronized apical four-chamber images acquired with ultrasound TVI. The results indicate that there is an apparent correlation between these data sets and the Ventricorder should therefore be able to produce data that could constitute the basis for the production of a CSD. What remain now is to confirm these results statistically with a larger test group and to investigate whether all the time instants needed for the production of a CSD can be identified objectively. / Hjärtdysfunktion är ett värdsligt utbrett problem som ligger bakom många dödsfall varje år. Studier har visat att många dödsfall som är relaterade till hjärtdysfunktion hade kunnat förebyggas om de upptäckts i tid. För närvarande är bland annat ultraljud och EKG oumbärliga metoder för diagnostisering och analys av hjärtfunktion. Ventricorder är en typ av radarsensor som utnyttjar ett brett frekvensspektrum, så kallat Ultra Wideband, och är tillverkad av det norska företaget Novelda. Ventricorder har visat sig kunna detektera exempelvis hjärtrörelser och andning men dess kliniska värde har ännu inte undersökts. Cardiac State Diagram (CSD) är ett prekliniskt mjukvaruverktyg för att visualisera hjärtats mekaniska funktion och som har bekräftats genom pilotstudier att kunna användas som underlag för diagnostik och bedömning av hjärtats funktion. Teoretiskt sett är CSD väl lämpat för att användas med Ventricordern eftersom Ventricordern registrerar små rörelser över tid och just ändringar över tid är precis vad som behövs för att skapa ett CSD. I dagsläget används vanligen vävnadsdoppler (TVI) för produktion av CSD och i denna masteruppsats undersöktes huruvida Ventricorder kan användas för att producera CSD. Detta gjordes genom att jämföra mätdata från Ventricorder med temporalt synkroniserade apikala fyrkammar-bilder framställda med vävnadsdoppler. Resultaten indikerar att det finns en påtaglig korrelation mellan dessa data och att mätdatat från en Ventricorder således bör kunna användas för produktion av CSD. Det kvarstår att bekräfta dessa resultat statistiskt med en större testgrupp och att undersöka om samtliga tidsmarkörer som behövs för produktion av ett CSD kan identifieras objektivt.

Les CSD ( Centre de Stockage de Déchet (CSD) de classe II) deviennent des ouvrages de plus en plus techniques au sein desquels interagissent des matériaux naturels (argile, sable), artificiels (géosynthétiques) et des déchets dont le comportement est variable à la fois dans le temps et dans l'espace. Ces interactions restent relativement méconnues car, si l'on appréhende relativement bien le comportement des argiles ou des géosynthétiques en conditions dites normales, le comportement des déchets, par leur hétérogénéité et leur caractère évolutif, est marqué par un grand nombre d'inconnues. Le programme de recherche faisant l'objet de ce mémoire est relatif à la compressibilité des déchets. Les enjeux sont importants. S'agissant des nouveaux sites ouverts, ceux-ci sont à la fois d'ordre sécuritaire (estimation des tassements différentiels que la couverture devra supporter, stabilité des talus), économique (prévision de la capacité de stockage ultime, optimisation de la durée d'exploitation et période de pose de la couverture finale) et réglementaire (anticipation par rapport à la hauteur maximale autorisée pour le tumulus de déchet). Quant aux anciens sites à réhabiliter, la maîtrise des tassements, bien que plus complexe, est tout aussi primordiale.

Helicopters in forward flight experience complex aerodynamic phenomena to various degrees. In low speed level flight, the vortex wake remains close to the rotor disk and interacts with the rotor blades to give rise to blade vortex interaction phenomena. In high speed flight, compressibility effects dominate leading to the formation of shocks. If the required thrust is high, the combination of high collective pitch and cyclic pitch variations give rise to three-dimensional dynamic stall phenomena. Maneuvers further exacerbate the unsteady airloads and affect rotor and hub design. The strength and durability of the rotor blades and hub components is dependent on accurate estimates of peak-to-peak structural loads. Accurate knowledge of control loads is important for sizing the expensive swash-plate components and assuring long fatigue life. Over the last two decades, computational tools have been developed for modeling rotorcraft aeromechanics. In spite of this progress, loads prediction in unsteady maneuvers which is critical for peak design loads continues to be a challenging task. The primary goal of this research effort is to investigate important physical phenomena that cause severe loads on the rotor in steady flight and in extreme maneuvers. The present work utilizes a hybrid Navier-Stokes/free-wake CFD methodology coupled to a finite element based multi-body dynamics analysis to systematically study steady level and maneuvering flight conditions. Computational results are presented for the UH-60A rotor for a parametric sweep of speed and thrust conditions and correlated with test data at the NFAC Wind Tunnel. Good agreement with test data has been achieved using the current methodology for trim settings and integrated hub loads, torque, and power. Two severe diving turn maneuvers for the UH-60A recorded in the NASA/Army Airloads Flight Tests Database have also been investigated. These maneuvers are characterized by high load factors and high speed flight. The helicopter experiences significant vibration during these maneuvers. Mean and peak-to-peak structural loads and extensive stall phenomena including an advancing side stall phenomena have been captured by the present analyses.

Simulations play an integral role in the understanding and development of rotor- craft aeromechanics. Computational Fluid Dynamics coupled with Computational Structural Dynamics (CFD/CSD) offers an excellent approach to analyzing rotors. These methods have been traditionally “loosely-coupled” where data are exchanged periodically, motion is prescribed for CFD, and the updated loads have a static component for CSD. Loosely-coupled CFD/CSD assumes the solution to be periodic, which may not be true for some simulations. “Tightly-coupled” CFD/CSD, where loads and motion are exchanged at each time step, does not make this periodic assumption and opens up new avenues of simulation to research. A major drawback to tightly-coupled CFD/CSD is an increase in computational cost. Different approaches are explored to reduce this cost as well as examine numerical implications in solutions from tightly and loosely-coupled CFD/CSD. A trim methodology optimized for tightly-coupled simulations is developed and found to bring trim costs within parity of loosely-coupled CFD/CSD simulations. Aerodynamic loading is found to be nearly similar for fixed controls. However, the lead-lag blade motion is determined to contain a harmonic in the tightly-coupled analysis that is not an integer multiple of the rotor speed. A hybrid CFD/CSD methodology employing the use of a free-wake code to model the far-field effects of the rotor wake is developed to aid in computational cost reduction. Investigation of this approach reveals that computational costs may be reduced while preserving solution accuracy. This work’s contributions to the community include the development of a trim algorithm appropriate for use in tightly-coupled CFD/CSD simulations along with a detailed examination of the physics predicted by loose and tight coupling for quasi-steady level flight conditions. The influence of the wake in such cases is directly examined using a modular hybrid coupling to a free-wake code that is capable of reduced cost computations.

The accurate prediction of rotor air loads is a current topic of interest in the rotorcraft community. The complex nature of this loading makes this problem especially difficult. Some of the issues that must be considered include transonic effects on the advancing blade, dynamic stall effects on the retreating blade, and wake vortex interactions with the blades, fuselage, and other components. There are numerous codes to perform these predictions, both aerodynamic and structural, but until recently each code has refined either the structural or aerodynamic aspect of the analysis without serious consideration to the other, using only simplified modules to represent the physics. More recent research has concentrated on combining high fidelity CFD and CSD computations to be able to use the most accurate codes available to compute both the structural and the aerodynamic aspects. The objective of the research is to both evaluate and extend a range of prediction methods comparing both accuracy and computational expense. This range covers many methods where the highest accuracy method shown is a delta loads coupling between an unstructured CFD code and a comprehensive code, and the lowest accuracy, but highest efficiency, is found through a free wake and comprehensive code coupling using simplified 2D aerodynamics. From here methods to improve the efficiency and accuracy of the CFD code will be considered through implementation of steady-state grid adaptation, a time accurate low Mach number preconditioning method, and the use of fully articulated rigid blade motion. The exact formulation of the 2D aerodynamic model used in the CSD code will be evaluated, as will efficiency improvements to the free wake code. The advantages of the free-wake code will be tested against a dynamic inflow model. A comparison of all of these methods will show the advantages and consequences of each combination, including the types of physics that each method is able to, or not able to, capture through examination of how closely each method matches flight test data.

The molecular mechanism of complementary sex determination in the haplodiploid organisms is poorly understood and has only been described in the honeybee Apis mellifera. In the haplodiploid system, males develop from unfertilized eggs and females from fertilized eggs. However, in some rare cases, diploid males develop from fertilized eggs. They can be distinguished from diploid and haploid males at the molecular level since they are heterozygous like females but are homozygous, like haploid males, at the sex determination locus. In this project, Osmia bicornis was chosen as the model organism, and the aim is to identify the complementary sex determination locus which should be homozygous in all diploid males. Bee nests were collected from the bees' natural habitat, and potential diploid males were identified. Data analysis of whole-genome sequencing on 17 potential diploid males was performed, which identified 80 candidate sex determination loci with 259 genes. Homologs of the Csd gene in A. mellifera were identified but not found in any candidate complementary sex determination loci.

Le stannate (SrSnO3) et le titanate de strontium (SrTiO3) sont des oxydes de type pérovskite, de structures orthorhombique (Pbnm) et cubique (Pm3m), respectivement. Ces matériaux ont reçu beaucoup d'attention ces dernières années en raison de leurs propriétés physiques et chimiques intéressantes conduisant à différents types d'applications technologiques. Pour ces raisons, ces deux matériaux ont été combinés pour obtenir la solution solide de SrSn1-xTixO3, sous forme de poudres et couches minces. Au niveau des poudres, la solution solide a présenté des transitions de phases successives allant d'une structure orthorhombique à tétragonale puis cubique avec l’augmentation de la quantité de Ti4+ dans le système. Ces transitions ont été observées par affinement Rietveld des spectres de diffraction des rayons X et confirmées par spectroscopie Raman. Ces différentes structures cristallines ont conduit à des propriétés différentes de photoluminescence dans le spectre visible, l’émission variant d’une région de basse énergie vers les régions de plus haute énergie avec l’augmentation de Ti4+ dans la structure (structure orthorhombique (SrSnO3), tétragonale (SrSn0,75Ti0,25O3) à cubique (SrSn0,50Ti0,50O3, SrSn0,25Ti0,75O3 et SrTiO3). Ces émissions sont probablement favorisées par différents types de défauts formés dans le gap d’énergie de ces matériaux. Par ailleurs, les couches minces ont montré différents types de croissance qui ont été fortement influencés par la nature cristalline du substrat, la composition des films ainsi que par la méthode de dépôt utilisée (dépôt par voie chimique en solution – CSD – et dépôt par ablation laser pulsé – PLD). Les films minces déposés sur silice sont polycristallins (croissance aléatoire des cristallites), les couches sur saphir-R (Al2O3-012) sont également polycristallines mais avec une orientation préférentielle (h00) quand préparées par PLD (croissance texturée), excepté SrTiO3 qui est épitaxié avec une rotation de 45º par rapport au plan du substrat de saphir-R. Tous les films déposés sur LAO (LaAlO3-100) sont épitaxiés (h00) quelque soit la méthode de dépôt. De plus, les caractéristiques morphologiques et les propriétés photocatalytiques des films ont également été fortement influencées par ces mêmes paramètres cités précédemment. Concernant les propriétés photocatalytiques, les films préparés par la méthode CSD ont été plus efficaces que ceux obtenus par PLD et les couches de compositions plus riches en Sn4+ ont été plus actives face à la photodégradation du colorant Remazol jaune or, l’efficacité maximale étant observée pour la couche polycristalline de SrSnO3 obtenue par CSD avec un pourcentage de dégradation et de décoloration d’environ 55 et 90 %, respectivement. Le type de croissance des films de SrSnO3 préparés par les deux méthodes de dépôt a aussi montré une forte influence sur la photodégradation du colorant, les couches polycristallines d’orientation aléatoire obtenues sur silice étant plus efficaces que les texturées, elles-mêmes plus efficaces que les couches épitaxiales. / Strontium stannate (SrSnO3) and titanate (SrTiO3) are perovskite type oxides that have orthorhombic (Pbnm) and cubic (Pm3m) structures, respectively. These materials have received much attention due to their interesting physical and chemical characteristics, leading to a variety of technological applications. In this sense, these two materials were combined to each other in order to obtain powders and thin films of a solid solution, SrSn1-xTixO3. In relation to the powders, this solid solution presented successive phase transitions ranging from orthorhombic and tetragonal structures to a cubic one with increasing of Ti4+ amount in the composition. These transitions were observed by XRD Rietveld refinement of the samples and confirmed by Raman spectroscopy. The different crystalline structures of the compositions within the solid solution led to different photoluminescent properties in the visible spectrum varying the range of emission, moving from a lower energy region to a higher one with increasing of Ti4+ in the structure (from orthorhombic (SrSnO3), tetragonal (SrSn0.75Ti0.25O3) to cubic (SrSn0.50Ti0.50O3 ; SrSn0.25Ti0.75O3 and SrTiO3). These emissions were probably favored by specific defects created inside the band gap of these materials. On the other hand, the thin films of this system showed different growth orientations that are associated to the crystalline nature of the substrates, the composition of the thin films and the deposition method (Chemical Solution Deposition - CSD - and Pulsed Laser Deposition - PLD). The films deposited on silica substrate were polycrystalline (random growth of the crystallites), whereas the films deposited on sapphire-R (Al2O3-012) were also polycrystalline, with a preferred orientation (h00) for the films deposited by PLD (textured growth), except SrTiO3 which was rotated 45° epitaxially in the sapphire plane. On the contrary, all of the films deposited on LAO (LaAlO3-100) had an (h00) epitaxial growth. In addition to that, the morphological characteristics and photocatalytic properties were strongly influenced also by the same parameters described above. Regarding the photocatalytic efficiency of the films, those obtained by CSD were more efficient than the ones obtained by PLD. Moreover, the films with Sn4+ richer compositions were the most active in the photodegradation of the azo dye Remazol yellow gold, reaching a maximum efficiency with the polycrystalline SrSnO3 thin film obtained by CSD whose degradation and decolorization percentage were 55 and 90 %, respectively. The type of orientation of the SrSnO3 films showed also a strong influence on the photodegradation of the dye. The polycrystalline films with a random orientation obtained on silica were more efficient than the textured films and these ones were more than the epitaxial films. / O estanato (SrSnO3) e o titanato de estrôncio (SrTiO3) são óxidos do tipo perovskita que apresentam estrutura ortorrômbica (Pbnm) e cúbica (Pm3m), respectivamente. Estes materiais têm recebido bastante atenção nos últimos anos devido às suas características físicas e químicas interessantes, levando à diferentes tipos de aplicações tecnológicas. Portanto, estes dois materiais foram combinados com intuito de obter uma solução sólida, SrSn1-xTixO3, na forma de pós e filmes finos. Em relação aos pós, esta solução sólida apresentou transições de fase sucessivas com o aumento da quantidade de Ti4+ no sistema, passando de uma estrutura ortorrômbica à tetragonal levando à cúbica. Estas transições foram observadas através de difração de raios-X e refinamento Rietveld, e confirmadas por espectroscopia vibracional Raman. Os diferentes tipos de estrutura cristalina das composições da solução sólida levaram a diferentes propriedades fotoluminescentes no espectro visível, variando a região de emissão de mais baixa à mais alta energia com o aumento de Ti4+ na estrutura, ou seja, passando da estrutura ortorrômbica (SrSnO3), tetragonal (SrSn0,75Ti0,25O3) até à cúbica (SrSn0,50Ti0,50O3, SrSn0,25Ti0,75O3 e SrTiO3). Estas emissões foram provavelmente favorecidas pelos tipos de defeitos específicos criados dentro do band gap destes materiais. Por outro lado, os filmes finos deste sistema apresentaram diferentes tipos de crescimento os quais são associados à natureza cristalina dos substratos, composição dos filmes e com o método de deposição utilizado (método de deposição química em solução - CSD - e método de deposição por laser pulsado – PLD). Os filmes depositados sobre sílica e safira-R (Al2O3-012) apresentaram como policristalinos (crescimento aleatorio dos cristalitos), enquanto os filmes depositados por PLD apresentaram orientação preferencial (h00) (crescimento texturizado), com exceção do filme de SrTiO3 que é epitaxial rotacionado em 45º no plano da safira-R. Todos os filmes depositados através dos dois métodos de deposição sobre LAO (LaAlO3-100) apresentaram um crescimento epitaxial (h00). Além disso, as características morfológicas e as propriedades fotocatalíticas também apresentaram forte influencia dos mesmos parâmetros acima citados. Em relação às propriedades fotocatalíticas, os filmes obtidos pelo método CSD apresentaram maior eficiência que os obtidos por PLD e os filmes com composições mais ricas em Sn4+ foram os mais ativos na fotodegradação do corante azo Remazol amarelo ouro, chegando a uma eficiência fotocatalítica máxima com o filme policristalino de SrSnO3 obtido por CSD com percentagem de degradação e de descoloração de 55 e 90 %, respectivamente. A orientação dos filmes de SrSnO3 também mostrou uma forte influencia na fotodegradação do corante, sendo os filmes policristalinos com orientação aleatória mais eficiente que o texturizado e estes por sua vez mais eficientes que os epitaxiais.

Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: This thesis reports an in-depth investigation of the intermolecular interaction motifs in secondary, primary and ammonium carboxylate salts. The investigation was conducted using the Cambridge Structural Database (CSD), together with a systematic steric-specific experimental study. The tendency in the literature has been to analyse organic salt crystal structures in terms of hydrogen bonding patterns, almost ignoring cation-anion interactions. This study focuses on the cation-anion interactions in secondary, primary and ammonium carboxylate salts, which have a direct effect on the formation of specific structural motifs. The ideas of ring-stacking and ring-laddering, which arise from the tendency of cations and anions to arrange themselves so as to maximise electrostatic interactions, have been applied to ammonium carboxylate salts. An extensive survey of organic ammonium carboxylate salt structures in the CSD has been carried out. The structural motifs in ammonium carboxylates were investigated, and a set of predictive rules for the pattern of intermolecular interactions in these salts was developed. Using these results, the formation of ring-stacking or ring-laddering in primary ammonium carboxylate salts can be predicted. The results from the CSD survey are discussed in Chapter 3. An experimental study has been carried out, which complements the results obtained from the CSD survey. The experimental study formed 19 novel ammonium carboxylate salts, of which 2 formed hydrates and 2 co-crystals of salts. The experimental results confirm what was found in the CSD survey, and this is discussed in Chapter 4. This study has found that the principle of ring-stacking and ring-laddering can be applied in a general form to the crystal structures of organic ammonium carboxylate salts. The size of the cation and the anion in these salts has a significant effect on the formation of structural motifs in the solid state. Interactions between cation and anion substituents also play an important role in the formation of particular structural motifs in ammonium carboxylate salts. / AFRIKAANSE OPSOMMING: In hierdie tesis word die intermolekulêre interaksie motiewe in die sekondêre, primêre en ammonium karbosilaat soute in-diepte ondersoek. Die studie is gedoen met behulp van die Cambridge Strukturele Databasis (CSD), saam met ‟n sistematiese steriesspesifieke eksperimentele studie. Die neiging in die literatuur is om organiese sout kristal strukture in terme van waterstofbindings patrone te analiseer sonder om katioon-anioon interaksies in ag te neem. Die studie fokus juis op hierdie katioon-anioon interaksies tussen sekondêre, primêre en ammonium karbosilaat soute wat ‟n direkte effek het op die vorming van spesifieke strukturele motiewe naamlik „ring-stacking‟ en „ring-laddering‟ wat hul oorsprong kry vanaf die neiging van katione en anione om hulself op so ‟n wyse te rangskik sodat die elektrostatiese interaksies ‟n maksimum kan bereik, op die ammonium karboksilaat soute. ‟n Volledige ondersoek van ammonium karboksilaat soute in die CSD is gedoen. Die strukturele motiewe in ammonium karboksilaat is ondersoek, en ‟n stel reels wat die patrone van intermolekulêre interaksies in hierdie soute voorspelis ontwikkel. Hierdie resultate kan gebruik word om die vorming van „ring-stacking‟ en „ring-laddering‟ in primêre ammonium karbosilaat soute te voorspel. Die resultate van die CSD ondersoek word bespreek in Hoofstuk 3. ‟n Eksperimentele studie is uitgevoer en die resultate hiervan komplimenteer die resultate van die CSD ondersoek. In die eksperimentele studie is 19 nuwe ammonium karboksilaat soute gekristaliseer, waarvan 2 hidraat-soute en 2 ko-kristal-van-soute is. Die eksperimentele resultate bevestig die bevindings van die CSD ondersoek, en dit word bespreek in Hoofstuk 4. Hierdie studie het gevind dat die beginsel van „ring-stacking‟ en „ring-laddering‟ kan in „n algemene vorm in die kristal strukture van organiese ammonium karboksilaat soute toegepas word. Die grootte van die katioon en anion in hierdie soute het ‟n beduidende effek op die vorming van strukturele motiewe in die vaste toestand. Interaksie tussen die katioon en anioon substituente speel „n belangrike rol in die vorming van spesifieke motiewe in ammonium karbosilaat soute.