Ce travail de recherche portant sur la compréhension des premières étapes de synthèse des zéolithes s'inscrit dans le cadre général de développements efficients de nouveaux catalyseurs performants. De nombreuses incertitudes demeurent quant aux mécanismes moléculaires de leur formation, en particulier lors de la nucléation en conditions de synthèse hydrothermale. Dans ce contexte, une méthodologie globale a été proposée afin d'évaluer l'impact des variables de synthèse sur la formation des espèces siliciques. La réalisation de ce travail a nécessité l'usage de différentes méthodes théoriques, combinant des calculs ab initio DFT et des simulations kMC. Un nouveau module kMC nommé Réacdiff a ainsi été développé et validé avec le modèle Lodka. L'extension des chemins réactionnels vers des espèces plus complexes a été effectuée et le recours à des modèles théoriques du type Brønsted-Evans-Polanyi (BEP) a été indispensable afin de les estimer rapidement. Un nouveau modèle des étapes réactionnelles d'oligomérisation a été proposé et a permis de tester l'effet crucial des agents organiques structurants (AS). Ces travaux ont permis de donner un nouveau regard sur la compréhension de la condensation des espèces siliciques durant les premières étapes de la synthèse des zéolithes. / This research work on the understanding of the early stages of zeolites synthesis fits withinthe general framework of the technological lock on the lower cost of new efficient catalysts synthesisoptimization. Many uncertainties remain with respect to the molecular mechanisms of their formation,in particular during nucleation in hydrothermal synthesis conditions. In this context, a comprehensivemethodology was proposed to assess the impact of synthesis variables in the formation of silicicspecies. This objective has required the use of different theoretical methods, combining ab initio DFTcalculations and kMC simulations. The creation of a new kMC module named Reacdiff has beendeveloped and validated with the Lodka model. The extension of reaction pathways to more complexspecies was carried out with the essential use of theoretical models like Brønsted-Evans-Polanyi(BEP) to quickly estimate. A new anionic model of the reaction steps of oligomerization has beenproposed and has allowed testing the crucial effect of organic templates. These thesis works gave anew understanding on the condensation of silicic species in early stages of zeolite synthesis.

Thesis (MOccTher (Interdisciplinary Health Sciences. Occupational Therapy))--University of Stellenbosch, 2010. / AFRIKAANSE OPSOMMING: AGTERGROND Dit is bekend dat vroeggebore babas met ʼn baie lae geboortemassa ʼn hoër insidensie van ontwikkelings-, gedrags- en mediese agterstande en verskeie leerprobleme toon teen die tyd dat hulle skoolgaande ouderdom bereik. Kommer bestaan ook oor die omgewingseffek van die neonatale intensiewe sorgeenheid op die sensoriese ontwikkeling van die vroeggebore baba en hoe dit tot bogenoemde agterstande kan bydra. Daar is verskillende benaderings wat daarop aanspraak maak dat hulle die probleem kan oplos, met kangaroemoedersorg (‘kangaroo mother care’) en ontwikkelingsorg (‘developmental care’) wat in die literatuur uitgesonder is as besonders belowend. Met die aanvang van hierdie studie was daar nog geen empiriese studies in die literatuur gerapporteer wat enige aansprake van hierdie benaderings bevestig het nie. Daar was dus ʼn behoefte vir ʼn empiries-nagevorsde program wat prakties in die neonatale intensiewe eenheid toegepas kon word met die oog op die vermindering van omgewingstressors ten opsigte van die vroeggebore baba se sensoriese sisteme. DOEL Die doel met die studie was om die invloed te bepaal van ʼn Sensoriese Ontwikkelingsorgprogram (‘Sensory Developmental Care Programme’), wat ʼn spesifieke kangaroemoedersorg- protokol insluit, op die sensoriese ontwikkeling van die vroeggebore baba met 'ʼn baie lae geboortemassa tot en met die ouderdom van 18 maande (gekorrigeerde ouderdom). METODOLOGIE ʼn Ewekansig-gekontroleerde studie is uitgevoer. Die studiesteekproef het bestaan uit 89 vroeggebore babas met ʼn baie lae geboortemassa wat in ʼn periode van 24 maande toegelaat is tot die neonatale eenheid van Tygerberg Hospitaal in Kaapstad, Suid-Afrika. Die babas is gewerf op grond van sekere kriteria en is dan daarna ewekansig aan een van twee groepe toegeken: 1) die intervensiegroep het sorg ontvang volgens die Sensoriese Ontwikkelingsorgprogram vir 10 dae; en 2) die kontrolegroep het ook vir 10 dae die standaardsorg van die eenheid ontvang. Die intervensiegroep het uit 45 babas bestaan, van wie 22 die studie voltooi het, terwyl die kontrolegroep uit 44 babas bestaan het van wie 20 die studie voltooi het. Beide studiegroepe is opgevolg op 6, 12 en 18 maande (gekorrigeerde ouderdom), by welke geleentheid die Sensoriese Funksietoets vir Babas (‘Test of Sensory Functions in Infants’) telkens toegepas is vir die assessering van sensoriese ontwikkeling. Op 18 maande (gekorrigeerde ouderdom) is ʼn assessering met die Griffiths Ontwikkelingskaal ook gedoen om funksies in die ander ontwikkelingsareas van die babas te bepaal. Toetsresultate is geanaliseer met behulp van herhaalde ANOVAmetings en die Bonferoni t-prosedure om die effek van die Sensoriese Ontwikkelingsorgprogram op die sensoriese ontwikkeling van die babas tot en met 18 maande (gekorrigeerde ouderdom) te bepaal. RESULTATE Die resultate van die vergelyking van die prestasie van beide groepe (groep-effek), gemeet met behulp van die Sensoriese Funksietoets vir Babas, is van groot belang vir hierdie studie. Die intervensiegroep het betekenisvol verskil op die totale telling (p<0.00), sowel as op die volgende vier van die vyf subtoets-tellings: respons op diepdruk (‘tactile deep pressure’) (p<0.03); motoriese aanpassingsreaksies (p<0.03); visuele tas-integrasie (p<0.00); en respons op vestibulêre stimulasie (p<0.01). GEVOLGTREKKING Die resultate van die studie dui aan dat die babas in die intervensiegroep baat gevind het by die Sensoriese Ontwikkelingsorgprogram met betrekking tot hul sensoriese funksies tot en met die ouderdom van 18 maande (gekorrigeerde ouderdom). Die Sensoriese Ontwikkelingsorgprogram het geblyk prakties sowel as suksesvol te wees met betrekking tot sy doel. Die Program sou daarom met vrug in ander neonatale intensiewe sorgeenhede aangewend kon word. / ENGLISH ABSTRACT: BACKGROUND Premature infants of very low birth weight are known to be inclined to developmental, medical, behavioural and various learning deficiencies by the time they reach schoolgoing age. Concerns have been raised about the effect of the neonatal intensive care unit environment on the sensory development of the premature infant and how this could contribute to these deficiencies. Various approaches claim to address this problem, of which kangaroo mother care and developmental care have in the literature been singled out as particularly promising. However, at the commencement of this study no empirical studies had been reported in the literature to confirm any of the claims of these approaches. Therefore, a need existed for an empirically researched programme that could be practically applied in the neonatal intensive care unit with a view to reducing environmental stressors regarding the sensory systems of the premature infant. AIM The aim of this study was to determine the influence of a Sensory Developmental Care Programme, which incorporated a specific kangaroo mother care protocol, on the sensory development of the very low birth weight premature infant, up to the age of 18 months (corrected age). METHODOLOGY A randomised controlled study was conducted. The study sample consisted of 89 very low birth weight premature infants, admitted during a 24-month period to the neonatal care unit at Tygerberg Hospital in Cape Town, South Africa. The infants were recruited by means of certain criteria and then randomly assigned to one of two groups: 1) the intervention group was cared for according to the Sensory Developmental Care Programme for ten recorded days; and 2) the control group that received the standard care of the unit, also for ten days. The intervention group consisted of 45 infants of whom 22 completed the study, while the control group consisted of 44 infants of whom 20 completed the study. Both study groups were followed up at six, 12 and 18 months (corrected age) when the Test of Sensory Functions in Infants was used to do a sensory developmental assessment. At 18 months (corrected age) a Griffiths Developmental Scale assessment was also conducted to determine function in other areas of development. Test results were analysed using repeated measures of ANOVA, and the Bonferoni t procedure to determine the effect that the Sensory Developmental Care Programme had on the sensory development of the infant up to 18 months (corrected age). RESULTS The results of the comparison of the performance of both groups (group effect), measured by the Test of Sensory Functions in Infants are of great importance to this study. The intervention group had a significant difference on the total score (p<0.00), as well as on the following four of the five sub-tests scores: reactivity to tactile deep pressure (p<0.03); adaptive motor functions (p<0.03); visual-tactile integration (p<0.00); and reactivity to vestibular stimulation (p<0.01). CONCLUSION The results of this study signify that the infants in the intervention group benefited from the Sensory Developmental Care Programme concerning their sensory functions up to the age of 18 months (corrected age). The Sensory Developmental Care Programme was demonstrated to be both practical and successful in terms of its aims. The Programme could therefore be fruitfully utilised in other neonatal intensive care units.

Advances in neonatology have led to increased numbers of high-risk neonates surviving and intensified interest in the developmental outcomes of this population. In the South African context prematurity and low birth weight are the most common causes of death in the perinatal period and the same risk factors that contribute to infant mortality also contribute to the surviving infants’ increased risk for developmental delays. As a result of the interacting biological and environmental risk factors of prematurity, low birth weight, poverty and HIV and AIDS in the South African context Kangaroo Mother Care (KMC) has been developed as best practice to promote infant survival and to facilitate mother-infant attachment. Mother-infant attachment may lead to synchronous interaction patterns between the mother and infant which forms the basis of early communication development. Early communication intervention (ECI) services are recommended as early as possible as high-risk infants are especially at risk for feeding difficulties and communication developmental delays. It is, however, not clear what the content of an ECI programme should be and how it should be implemented according to the changing communication and feeding developmental needs of the infant while receiving KMC. There appears to be a dearth of research on the earliest stages of communication development in high-risk neonates, which should form the foundation of such a programme. A descriptive survey was conducted to describe the development of 25 high-risk infants and their mothers’ changing needs from admission to discharge from a KMC unit. Each participant and mother dyad was followed up over an average of 11 days of data collection with three to four data collection sessions. Data was collected by means of direct observation during routine care-giving activities. The different developmental subsystems of the participants’ feeding, communication, neuro-behavioural organization and mother-neonate interaction were described. The results demonstrated that subtle, but definite changes could be observed in the participants’ development. Development in all the different areas occurred over time as the participants progressed through the three developmental states of the in-turned state, coming-out state and reciprocity state. As the participants progressed during the 11 days of data collection and were increasingly able to attend to their environment, they also developed the ability to regulate and organize their own behaviour in order to develop more complex communication, feeding and interaction skills with their mothers. The functioning of the participants’ sensory systems developed in a specific order namely tactile, auditory and then visual. Although the participants developed consistently throughout their stay in the KMC unit, mother-neonate interaction never reached optimal levels. The importance of an individualized training programme for each mother is reflected in the finding that the neonate’s developmental level and progress needs to be considered when implementing the ECI programme. The need for speech-language therapy involvement in KMC is emphasized in the light of a shortage of practicing speech-language therapists in South Africa. It is therefore imperative that the prevention of communication delays and feeding difficulties in high-risk neonates as well as parent training assume priority. / Dissertation (MCommunication Pathology)--University of Pretoria, 2008. / Speech-Language Pathology and Audiology / unrestricted

Self-organization of regular surface pattern under ion beam erosion was described in detail by Navez in 1962. Several years later in 1986 Bradley and Harper (BH) published the first self-consistent theory on this phenomenon based on the competition of surface roughening described by Sigmund’s sputter theory and surface smoothing by Mullins-Herring diffusion. Many papers that followed BH theory introduced other processes responsible for the surface patterning e.g. viscous flow, redeposition, phase separation, preferential sputtering, etc. The present understanding is still not sufficient to specify the dominant driving forces responsible for self-organization. 3D atomistic simulations can improve the understanding by reproducing the pattern formation with the detailed microscopic description of the driving forces. 2D simulations published so far can contribute to this understanding only partially. A novel program package for 3D atomistic simulations called trider (TRansport of Ions in matter with DEfect Relaxation), which unifies full collision cascade simulation with atomistic relaxation processes, has been developed. The collision cascades are provided by simulations based on the Binary Collision Approximation, and the relaxation processes are simulated with the 3D lattice kinetic Monte-Carlo method. This allows, without any phenomenological model, a full 3D atomistic description on experimental spatiotemporal scales. Recently discussed new mechanisms of surface patterning like ballistic mass drift or the dependence of the local morphology on sputtering yield are inherently included in our atomistic approach. The atomistic 3D simulations do not depend so much on experimental assumptions like reported 2D simulations or continuum theories. The 3D computer experiments can even be considered as ’cleanest’ possible experiments for checking continuum theories. This work aims mainly at the methodology of a novel atomistic approach, showing that: (i) In general, sputtering is not the dominant driving force responsible for the ripple formation. Processes like bulk and surface defect kinetics dominate the surface morphology evolution. Only at grazing incidence the sputtering has been found to be a direct cause of the ripple formation. Bradley and Harper theory fails in explaining the ripple dynamics because it is based on the second-order-effect ‘sputtering’. However, taking into account the new mechanisms, a ‘Bradley-Harper equation’ with redefined parameters can be derived, which describes pattern formation satisfactorily. (ii) Kinetics of (bulk) defects has been revealed as the dominating driving force of pattern formation. Constantly created defects within the collision cascade, are responsible for local surface topography fluctuation and cause surface mass currents. The mass currents smooth the surface at normal and close to normal ion incidence angles, while ripples appear first at θ ≥ 40°. The evolution of bimetallic interfaces under ion irradiation is another application of trider described in this thesis. The collisional mixing is in competition with diffusion and phase separation. The irradiation with He+ ions is studied for two extreme cases of bimetals: (i) Irradiation of interfaces formed by immiscible elements, here Al and Pb. Ballistic interface mixing is accompanied by phase separation. Al and Pb nanoclusters show a self-ordering (banding) parallel to the interface. (ii) Irradiation of interfaces by intermetallics forming species, here Pt and Co. Well-ordered layers of phases of intermetallics appear in the sequence Pt/Pt3Co/PtCo/PtCo3/Co. The trider program package has been proven to be an appropriate technique providing a complete picture of mixing mechanisms.

Gasphasenabscheidungen werden zur Produktion dünner Schichten in der Mikro- und Nanoelektronik benutzt, um eine präzise Kontrolle der Schichtdicke im Sub-Nanometer-Bereich zu erreichen. Elektronische Eigenschaften der Schichten werden dabei von strukturellen Eigenschaften determiniert, deren Bestimmung mit hohem experimentellem Aufwand verbunden ist. Die vorliegende Arbeit erweitert ein hochparalleles Modell zur atomistischen Simulation des Wachstums und der Struktur von Dünnschichten, welches Molekulardynamik (MD) und Kinetic Monte Carlo-Methoden (KMC) kombiniert, um die Beschreibung beliebiger Gasphasenabscheidungen. KMC-Methoden erlauben dabei die effiziente Betrachtung der Größenordnung ganzer Nano-Bauelemente, während MD für atomistische Genauigkeit sorgt. Erste Ergebnisse zeigen, dass das Parsivald genannte Modell Abscheidungen in Simulationsräumen mit einer Breite von 0.1 µm x 0.1 µm effizient berechnet, aber auch bis zu 1 µm x 1 µm große Räume mit 1 Milliarden Atomen beschreiben kann. Somit lassen sich innerhalb weniger Tage Schichtabscheidungen mit einer Dicke von 100 Å simulieren. Die kristallinen und amorphen Schichten zeigen glatte Oberflächen, wobei auch mehrlagige Systeme auf die jeweilige Lagenrauheit untersucht werden. Die Struktur der Schicht wird hauptsächlich durch die verwendeten molekulardynamischen Kraftfelder bestimmt, wie Untersuchungen der physikalischen Gasphasenabscheidung von Gold, Kupfer, Silizium und einem Kupfer-Nickel-Multilagensystem zeigen. Stark strukturierte Substrate führen hingegen zu Artefakten in Form von Nanoporen und Hohlräumen aufgrund der verwendeten KMC-Methode. Zur Simulation von chemischen Gasphasenabscheidungen werden die Precursor-Reaktionen von Silan mit Sauerstoff sowie die Hydroxylierung von alpha-Al2O3 mit Wasser mit reaktiven Kraftfeldern (ReaxFF) berechnet, allerdings ist weitere Arbeit notwendig, um komplette Abscheidungen auf diese Weise zu simulieren. Mit Parsivald wird somit die Erweiterung einer Software präsentiert, die Gasphasenabscheidungen auf großen Substraten effizient simulieren kann, dabei aber auf passende molekulardynamische Kraftfelder angewiesen ist.

Dünne Filme aus konjugierten Molekülen werden vermehrt in der organischen Optoelektronik, Bio-Sensorik und Oberflächenmodifikationen eingesetzt. Jedoch steckt das nanoskopische Verständnis von elementaren Prozessen bzgl. des molekularen Wachstums, der Film-Stabilität und thermisch-mechanischer Eigenschaften noch in den Kinderschuhen. Im ersten Teil dieser Arbeit nutzen wir Echtzeit in situ spekulare und diffuse Röntgenstreuung in Kombination mit Kinetik-Monte-Carlo Simulationen, um die Nukleation und das Multilagen-Wachstum von C60 zu studieren. Wir quantifizieren einen konsistenten Satz von Energieparametern, die die Oberflächenprozesse während des Wachstums beschreiben: eine effektive Ehrlich-Schwoebel Barriere von EES = 110 meV, eine Oberflächendiffusions-Barriere von ED = 540 meV und die Bindungsenergie von EB = 130 meV. Durch die Analyse der Teilchendynamiken finden wir, dass die laterale Diffusion ähnlich derer von Kolloiden ist, jedoch weist die Stufenkanten-Diffusion eine atom-ähnlichen Schwoebel-Barriere auf. Außerdem haben wir für die erste Monolage ein thermisch-aktiviertes Dewetting nach dem Wachstum von C60 auf Mica mit einer effektiven Aktivierungsbarriere von (0.33 ± 0.14) eV für die Aufwärts-Diffusion beobachtet. Im zweiten Teil der Arbeit untersuchen wir die thermomechanischen Eigenschaften der supra-molekularen Anordnung von dem organischen Halbleiter PTCDI-C8. Temperaturabhängige GIXD-Experimente decken einen außergewöhnlich großen positiven und negativen thermischen Expansionskoeffizienten der Kristallstruktur auf. Die Moleküle vollführen kooperative rotierende Bewegungen als Reaktion auf die Temperaturänderung, die zu dieser anomalen thermischen Expansion führen. Unsere Beschreibung der Bewegungen einzelner adsorbierter Moleküle während des Wachstums und der kooperativen Bewegungen einzelner Moleküle in supra-molekularen Ensembles auf der molekularen Skala wird die weitere Arbeit auf dem Weg zu funktionalen molekularen dünnen Filmen beleben. / Thin films of conjugated molecules are increasingly used in organic optoelectronics, biosensing and surface modification. However, nanoscopic understanding of elementary processes regarding the molecular film growth, the stability of these films and regarding the thermal and mechanical properties of supra-molecular assemblies are in its infancy. In the first part of this thesis we use real-time in situ specular and diffuse X-ray scattering in combination with kinetic Monte Carlo simulations to study C60 nucleation and multilayer growth. We quantify a consistent set of energy parameters, which describe the surface processes during growth, yielding an effective Ehrlich-Schwoebel barrier of EES = 110 meV, a surface diffusion barrier of ED = 540 meV and a binding energy of EB = 130 meV. Analysing the particle-resolved dynamics, we find that the lateral diffusion is similar to colloids, but step-edge crossing is characterized by an atom-like Schwoebel barrier. Furthermore, a thermally-activated post-growth dewetting for C60 on mica has been observed for the first monolayer with an effective activation barrier for upward interlayer transport of (0.33 ± 0.14) eV. In the second part we investigate the thermomechanical properties of the supra-molecular assembly of the organic semiconductor PTCDI-C8. Temperature-dependent Grazing Incidence X-ray Diffraction (GIXD) experiments reveal extraordinary large positive and, surprisingly, negative thermal expansion coefficients of the thin film crystal structure. The molecules perform temperature-controlled cooperative rotational motions leading to the change of the molecular crystal structure at different temperatures. We hope that our molecular scale picture of the movement of single ad-molecules during growth and the cooperative motions of single molecules in supra-molecular ensembles will stimulate further work towards the optimized, rational design of functional molecular thin films and nanomaterials.

Self-organization of regular surface pattern under ion beam erosion was described in detail by Navez in 1962. Several years later in 1986 Bradley and Harper (BH) published the first self-consistent theory on this phenomenon based on the competition of surface roughening described by Sigmund's sputter theory and surface smoothing by Mullins-Herring diffusion. Many papers that followed BH theory introduced other processes responsible for the surface patterning e.g. viscous flow, redeposition, phase separation, preferential sputtering, etc. The present understanding is still not sufficient to specify the dominant driving forces responsible for self-organization. 3D atomistic simulations can improve the understanding by reproducing the pattern formation with the detailed microscopic description of the driving forces. 2D simulations published so far can contribute to this understanding only partially. A novel program package for 3D atomistic simulations called TRIDER (TRansport of Ions in matter with DEfect Relaxation), which unifies full collision cascade simulation with atomistic relaxation processes, has been developed. The collision cascades are provided by simulations based on the Binary Collision Approximation, and the relaxation processes are simulated with the 3D lattice kinetic Monte-Carlo method. This allows, without any phenomenological model, a full 3D atomistic description on experimental spatiotemporal scales. Recently discussed new mechanisms of surface patterning like ballistic mass drift or the dependence of the local morphology on sputtering yield are inherently included in our atomistic approach. The atomistic 3D simulations do not depend so much on experimental assumptions like reported 2D simulations or continuum theories. The 3D computer experiments can even be considered as 'cleanest' possible experiments for checking continuum theories. This work aims mainly at the methodology of a novel atomistic approach, showing that: (i) In general, sputtering is not the dominant driving force responsible for the ripple formation. Processes like bulk and surface defect kinetics dominate the surface morphology evolution. Only at grazing incidence the sputtering has been found to be a direct cause of the ripple formation. Bradley and Harper theory fails in explaining the ripple dynamics because it is based on the second-order-effect 'sputtering'. However, taking into account the new mechanisms, a 'Bradley-Harper equation' with redefined parameters can be derived, which describes pattern formation satisfactorily. (ii) Kinetics of (bulk) defects has been revealed as the dominating driving force of pattern formation. Constantly created defects within the collision cascade, are responsible for local surface topography fluctuation and cause surface mass currents. The mass currents smooth the surface at normal and close to normal ion incidence angles, while ripples appear first at incidence angles larger than 40°. The evolution of bimetallic interfaces under ion irradiation is another application of TRIDER described in this thesis. The collisional mixing is in competition with diffusion and phase separation. The irradiation with He ions is studied for two extreme cases of bimetals: (i) Irradiation of interfaces formed by immiscible elements, here Al and Pb. Ballistic interface mixing is accompanied by phase separation. Al and Pb nanoclusters show a self-ordering (banding) parallel to the interface. (ii) Irradiation of interfaces by intermetallics forming species, here Pt and Co. Well-ordered layers of phases of intermetallics appear in the sequence Pt/Pt3Co/PtCo/PtCo3/Co. The TRIDER program package has been proven to be an appropriate technique providing a complete picture of mixing mechanisms.

Self-organization of regular surface pattern under ion beam erosion was described in detail by Navez in 1962. Several years later in 1986 Bradley and Harper (BH) published the first self-consistent theory on this phenomenon based on the competition of surface roughening described by Sigmund's sputter theory and surface smoothing by Mullins-Herring diffusion. Many papers that followed BH theory introduced other processes responsible for the surface patterning e.g. viscous flow, redeposition, phase separation, preferential sputtering, etc. The present understanding is still not sufficient to specify the dominant driving forces responsible for self-organization. 3D atomistic simulations can improve the understanding by reproducing the pattern formation with the detailed microscopic description of the driving forces. 2D simulations published so far can contribute to this understanding only partially. A novel program package for 3D atomistic simulations called TRIDER (TRansport of Ions in matter with DEfect Relaxation), which unifies full collision cascade simulation with atomistic relaxation processes, has been developed. The collision cascades are provided by simulations based on the Binary Collision Approximation, and the relaxation processes are simulated with the 3D lattice kinetic Monte-Carlo method. This allows, without any phenomenological model, a full 3D atomistic description on experimental spatiotemporal scales. Recently discussed new mechanisms of surface patterning like ballistic mass drift or the dependence of the local morphology on sputtering yield are inherently included in our atomistic approach. The atomistic 3D simulations do not depend so much on experimental assumptions like reported 2D simulations or continuum theories. The 3D computer experiments can even be considered as 'cleanest' possible experiments for checking continuum theories. This work aims mainly at the methodology of a novel atomistic approach, showing that: (i) In general, sputtering is not the dominant driving force responsible for the ripple formation. Processes like bulk and surface defect kinetics dominate the surface morphology evolution. Only at grazing incidence the sputtering has been found to be a direct cause of the ripple formation. Bradley and Harper theory fails in explaining the ripple dynamics because it is based on the second-order-effect 'sputtering'. However, taking into account the new mechanisms, a 'Bradley-Harper equation' with redefined parameters can be derived, which describes pattern formation satisfactorily. (ii) Kinetics of (bulk) defects has been revealed as the dominating driving force of pattern formation. Constantly created defects within the collision cascade, are responsible for local surface topography fluctuation and cause surface mass currents. The mass currents smooth the surface at normal and close to normal ion incidence angles, while ripples appear first at incidence angles larger than 40°. The evolution of bimetallic interfaces under ion irradiation is another application of TRIDER described in this thesis. The collisional mixing is in competition with diffusion and phase separation. The irradiation with He ions is studied for two extreme cases of bimetals: (i) Irradiation of interfaces formed by immiscible elements, here Al and Pb. Ballistic interface mixing is accompanied by phase separation. Al and Pb nanoclusters show a self-ordering (banding) parallel to the interface. (ii) Irradiation of interfaces by intermetallics forming species, here Pt and Co. Well-ordered layers of phases of intermetallics appear in the sequence Pt/Pt3Co/PtCo/PtCo3/Co. The TRIDER program package has been proven to be an appropriate technique providing a complete picture of mixing mechanisms.

<p>Kangaroo mother care (KMC) was first initiated in Colombia due to shortages of incubators and the incidence of severe hospital infections of new-born infants during hospital stay (Feldman, 2004). Currently it is identified by UNICEF as a universally available and biologically sound method of care for all new-borns, particularly for low birth weight infants (Department of Reproductive Health and Research, 2003) in both developed and developing countries. The Western Cape Provincial Government implemented a policy on KMC as part of their strategy to decrease the morbidity and mortality of premature infants in 2003 (Kangaroo Mother Care Provincial task team, 2003). Essential components of KMC are: skin-to-skin contact for 24 hours per day (or as great a part of the day as possible), exclusive breastfeeding and support to the motherinfant dyad. Successful implementation of KMC requires relevant education of nurses, education of mothers on KMC by nursing staff, monitoring of the implementation of KMC by nurses, planning for a staff mix with varying levels of skill and experience with KMC, the identification of institution specific barriers to the implementation of KMC, and the implementation of institution specific strategies to overcome these barriers (Wallin,et al., 2005 / Bergman &amp / Jurisco, 1994 / Cattaneo, et al., 1998). This study aims to determine the knowledge of and attitude towards kangaroo mother care, of nursing staff and kangaroo mothers in the Eastern sub-district of Cape Town.</p>

<p>Kangaroo mother care (KMC) was first initiated in Colombia due to shortages of incubators and the incidence of severe hospital infections of new-born infants during hospital stay (Feldman, 2004). Currently it is identified by UNICEF as a universally available and biologically sound method of care for all new-borns, particularly for low birth weight infants (Department of Reproductive Health and Research, 2003) in both developed and developing countries. The Western Cape Provincial Government implemented a policy on KMC as part of their strategy to decrease the morbidity and mortality of premature infants in 2003 (Kangaroo Mother Care Provincial task team, 2003). Essential components of KMC are: skin-to-skin contact for 24 hours per day (or as great a part of the day as possible), exclusive breastfeeding and support to the motherinfant dyad. Successful implementation of KMC requires relevant education of nurses, education of mothers on KMC by nursing staff, monitoring of the implementation of KMC by nurses, planning for a staff mix with varying levels of skill and experience with KMC, the identification of institution specific barriers to the implementation of KMC, and the implementation of institution specific strategies to overcome these barriers (Wallin,et al., 2005 / Bergman &amp / Jurisco, 1994 / Cattaneo, et al., 1998). This study aims to determine the knowledge of and attitude towards kangaroo mother care, of nursing staff and kangaroo mothers in the Eastern sub-district of Cape Town.</p>