Die vorliegende Dissertation untersucht die Kontextabhängigkeit von Konsumentenpräferenzen in Folge eines Marktaustritts in 4 Aufsätzen. Aufsatz 1 diskutiert Auswirkungen einer Auslistung auf Kundenreaktionen. Zwei empirische Studien belegen die Existenz eines negativen Ähnlichkeits-, Attraktions- und Kompromisseffektes und zeigen wesentliche Determinanten einer markentreuen Reaktion auf. Aufsatz 2 bestätigt die Hypothesen über negative Kontexteffekte für Markeneliminierungen in verschiedenen experimentellen Situationen und Produktkategorien. Das sich ergebende Substitutionsverhalten resultiert durchweg in höheren Verlusten für Hersteller als für Händler. Aufsatz 3 diskutiert das Substitutionsverhalten in Out-of-Stock Situationen. Promotion wird hierbei als wesentlicher Einflussfaktor herangezogen. Verschiedene Online-Experimente demonstrieren einen negativen Ähnlichkeitseffekt für die temporäre Nichtverfügbarkeit von Produkten, welcher sich jedoch für preisreduzierte Güter des täglichen Bedarfs verringert. Werden ähnliche Substitute preislich reduziert angeboten, wird der negative Ähnlichkeitseffekt verstärkt. Der Effekt wird hingegen von einem Attraktionseffekt überlagert, wenn unähnliche Alternativen im Sonderangebot sind. Aufsatz 4 untersucht wesentliche Einflussfaktoren eines negativen Attraktionseffektes. In Anlehnung an das von Mishra et al. (1993) entwickelte Kausalmodell zur Neuprodukteinführung, wird ein adaptiertes ganzheitliches Strukturgleichungsmodell für den Marktaustritt getestet. Als wesentliche Treiber des betrachteten Phänomens resultieren die Konstrukte Anteil des Decoys, Präferenzstärke und Informationsrelevanz. / This thesis investigates the context-dependence of preferences in consequence of market exits in 4 essays. Essay 1 discusses the effect of brand delisting on customer responses. On the basis of two empirical studies, the existence of a negative similarity, a negative attraction and a negative compromise effect is revealed and key determinants of a brand loyal reaction are analyzed. Essay 2 supports the hypotheses on negative context effects for brand removals across different experimental settings and product categories. The resultant switching patterns collectively lead to bigger damages for manufacturers than for retailers. Essay 3 investigates preference shifts in out-of-stock situations by including promotion as essential driver. A series of online experiments demonstrate that for temporal unavailability of products, substitution behavior correspond to a negative similarity effect which is, however, reduced for stock-outs of low involvement fast moving consumer goods on promotion. While the negative similarity effect is enforced for promotions of similar substitutes, it is ruled out by the simultaneous occurrence of an attraction effect when dissimilar substitutes are offered at a reduced price. Essay 4 studies important antecedent variables of the negative attraction effect. In reference to the causal model on product introduction developed by Mishra et al. (1993), an adapted holistic framework for product exit is tested by using structural equation modeling. The results emphasize decoy share, preference strength and information relevance as major drivers of the considered phenomenon.

Os requisitos técnicos da qualidade da imagem em mamografia estabelecidos por normas nacionais e internacionais incluem parâmetros de qualidade que podem ser avaliados através da realização de testes periódicos. Estes parâmetros podem ser medidos com a aquisição e leitura de imagens de objetos (phantoms) que simulam as estruturas presentes em uma mamografia. O phantom CDMAM foi confeccionado especificamente para a realização de testes que utilizam um procedimento padrão para se determinar um limiar de contraste para cada diâmetro de disco presentes em suas imagens. No entanto, esta tarefa é bastante trabalhosa e consome tempo, além de estar sujeita a uma significativa dependência do observador, diminuindo a precisão das aferições. Nesse sentido, o propósito deste trabalho é o desenvolvimento de um software que auxilie o profissional na realização dos testes, reduzindo a subjetividade devida aos observadores e correlacionando as leituras automatizadas com o sistema visual humano, sem a necessidade de se efetuar a correção dos resultados, como é realizado em diversos trabalhos encontrados na literatura. Para isso, foram utilizadas imagens obtidas por cinco sistemas CR e um método de detecção baseado na confecção de filtros circulares correlatores. A correlação com a visão humana fundamentou-se nos parâmetros de Weber, que descrevem o comportamento do sistema visual na discriminação do contraste em imagens digitais. A classificação dos discos contidos na imagem do phantom entre visível ou não visível foi efetuada a partir de uma ferramenta de mineração de dados conhecida como WEKA (Waikato Environment for Knowledge Analysis) associada ao algoritmo J48, que promove a construção de modelos de árvore de decisão. O resultado da implementação destas árvores de decisão foi a obtenção de um sistema de auxílio ao especialista que reforça a sua integridade na avaliação a partir de resultados estáveis e de fácil interpretação, atingindo acurácias de até 95%. / Technical requirements of image quality in mammography established by national and international norms include quality parameters which can be achieved by conducting periodic tests. It is recommended that some quality parameters are measured from images acquired by exposing specific phantoms, as CDMAM, in such systems. Nevertheless, this task is hard-working and time consuming, besides to be subject to a significant dependence of the observer, reducing the measurements accuracy. Accordingly, the purpose of this work is the development of a software to assist in the professional testing, reducing the subjectivity due to the observers and correlating the automated readings with the human visual system, without the need to make the correction of the results, as is done in many studies in the literature. For this, we used 57 images obtained for five CR systems and a method of detection based on circular correlators filters. The correlation with human vision was based on the Weber\'s parameters which describe the behavior of the visual system to discriminate the contrast in digital images. The classification of the image discs between visible or not visible was made from a data mining tool known as WEKA (Waikato Environment for Knowledge Analysis) associated with the J48 algorithm which promotes the construction of decision tree models. The result of the decision trees implementation was a system to aid the specialist, reinforcing the integrity of the assessment using stable results, easily interpreted, and reaching accuracies of up to 95%.

Det finns ett fåtal studier som berör objekthöjders betydelse för bildövertäckning vid UAV-fotografering. Därför är det intressant att undersöka hur objekthöjder, bildövertäckningar, och flyghöjder påverkar varandra samt hur de gemensamt påverkar kvaliteten på data. Syfte är att undersöka hur bildövertäckningen, och flyghöjder påverkar kvaliteten på ortofoton och digitala ytmodeller. Samt undersöka hur objekthöjder påverkar bildövertäckningen. Kriteriet för studieområdet var att det skulle finnas ett högt objekt. Studien utfördes därför i Inre hamn i Karlstad som omfattar Löfbergsskrapan på ca 42 m. Studien avser UAVs som begränsas enligt Transportstyrelsens regler (TSFS 2017:110). Målet var att presentera referenstabeller till företag eller privatpersoner som samlar in mätdata med UAV. Data samlades in på flyghöjderna; 120 m och 90 m, med bildövertäckningarna; 60/60 %, 80/80 %, och 90/90 %. Höjddata för Löfbergsskrapan mättes in med Satlab GNSS. Resultatet visade att bildövertäckningen 60/60 % inte var användbart inom ett område med maximal objekthöjd 42 m. Det behövdes ≥80/80 % bildövertäckning för att få en bra markupplösning. I studien undersöktes även hur mycket bildövertäckningen kan förändras när objekt ligger under markytans plan. Resultatet visar att bildövertäckningen ökar när objektet eller ytan avviker tillräckligt mycket ifrån markytans plan och minskar om det går tillräckligt högt ovanför markytan. Slutsatsen föreslår att bildövertäckningen ska vara minst 80/80 % för flyghöjderna 120 m och 90 m. De inställningarna innebär att byggnader på ca 42 m höjd ska representeras med 2-3 cm markupplösning i ortofoton och digitala ytmodeller samt omfatta en resursvänlig metod. Slutsatsen menar att förändringen av bildövertäckningen varierar mellan 10-50 % när markytan ligger ca 42 m lägre än starthöjden för en UAV. / There are a few available studies purely focusing on the object heights significance on image overlap in UAV-photogrammetry. Therefore, it is interesting to examine how object heights, image overlaps, and altitudes affect each other and how they jointly affect data quality. The purpose is to examine how image overlap, and altitude affect the quality of orthophotos and digital elevation models. And also examine how object heights affect image overlap. The study area was selected with the criterion of including a high rise building. Therefore, the study area was Inre hamn in Karlstad City covering Löfbergsskrapan, a 42 m high coffee roasting house. The study refers to UAVs restricted according to rules set by Transportstyrelsen (TSFS 2017:110). The objective was to present useful reference tables for companies and individuals working with UAV-data. Data was collected on the altitudes; 120 m and 90 m with an image overlap of; 60/60 %, 80/80 %, and 90/90 %. Elevation values was collected with Satlab GNSS. Results showed that using an image overlap of 60/60 % for both altitudes was not viable in an area covering an object of 42 m high. The image overlap should be at least ≥80/80 % to cover objects of 42 m high. The objective was also to examine how image overlap differ when an object is below ground level. Results showed that image overlap increases when an object or surface differ 42 m from ground level and decreases if the object is above ground level. The conclusion suggests that in order to include objects of 42 m high in an area the image overlap should be at least 80/80 % for both altitudes (120 m and 90 m). With those settings the ground resolution in orthophotos and digital elevations models should be 2-3 cm. It was also estimated that the image overlap may alter from settings anywhere between 10-50 % when ground level is 42 m below the point of departure of the UAV.

Sistemas ultrassônicos tiveram uma evolução tecnológica nos últimos anos e isso permitiu que seus recursos de hardware e software pudessem ser explorados para extrair informações, auxiliando em diagnósticos e tratamentos mais eficazes. Através da análise do comportamento mecânico de tecidos moles, técnicas como elastografia estática, vibroacustografia, elastografia transiente e elastografia remota tiveram seu papel reconhecido na complementação do diagnóstico clínico. Contudo, a propagação destas técnicas na medicina tem sido restringida pela acessibilidade às tecnologias utilizadas, ausências de parâmetros quantitativos, dificuldade da excitação em estruturas profundas e acesso a informações em níveis moleculares. Este estudo aborda o desenvolvimento de um protocolo para efetuar medidas quantitativas de viscoelasticidade em tecidos moles marcados com nanopartículas de óxido de ferro usando excitação magnética e medição ultrassônica. Ao aplicar uma força magnética pulsada em um meio fluido marcado com nanopartículas magnéticas, um movimento é induzido, gerando uma onda de cisalhamento que se propaga pelo tecido. A propagação dessa onda é mapeada usando a técnica de ultrassom pulso-eco e processamento de dados usando métricas de similaridades entre ecos (mapa de rf) consecutivos. Nos estudos realizados em mimetizadores de tecidos moles (phantom) com características mecânicas equivalentes ao tecido biológico, a amplitude de deslocamento dessas ondas é da ordem de micrometro. Através da medida da velocidade deslocamento dessa onda avaliou-se o melhor modelo reológico para quantificar os parâmetros mecânicos de viscosidade e elasticidade. Os resultados mostraram a eficiência desta técnica ao quantificar os valores viscoelásticos condizentes com a literatura e a comprovação da análise de tecidos moles marcado com nanopartículas excitadas com campo magnético de baixa intensidade, possibilitando uma avaliação em âmbito molecular em tecidos moles. / Ultrasonic systems had a technological development in recent years and allowed their hardware and software resources could be exploited to extract information, assisting in more effective diagnosis and treatment. Through the mechanical behavior analysis of soft tissue techniques such as static elastography, vibroacoustography, transient elastography and remote elastography had recognized role in complementing clinical diagnosis. However, the spread of these techniques in medicine has been restricted by accessibility to the technologies used, quantitative parameters absences, difficulty of deep structures access and information on molecular levels. This study addresses the development of a protocol to make quantitative measurements of viscoelastic soft tissue labeled with iron oxide nanoparticles using magnetic excitation and ultrasonic measurement. By applying a pulsed magnetic force in a fluid medium labeled with magnetic nanoparticles, a motion is induced, generating a shear wave that propagates through the tissue. The propagation of this wave is mapped using the pulse-echo ultrasound technique and data processing using similarities measurements between echoes (rf map) consecutive. In studies of soft tissue-mimicking phantom with mechanical properties equivalent to the biological tissue, the displacement amplitude of these waves is of micrometer order. By measuring the shear wave velocity, it was evaluated the best rheological model for quantifying mechanical parameters of viscosity and elasticity. The results showed the efficiency of this technique to quantify the viscoelastic values consistent with the literature and the evidence of soft tissue analysis labeled excited nanoparticles with low intensity magnetic field, providing an assessment on the molecular level in soft tissues.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Breast cancer is the type of cancer that affects more women worldwide. Its early detection is key to achieve its treatment and, consequently, reduce its mortality rate. Mammography is considered the most suitable technique for this detection, which is based on the visualization of small structures and patterns that may represent cancerous lesions. But for visualization of these structures, the quality control of mammographic images and the training of residents and radiologists is required. With this in mind, this study aimed the development and confection of three breast simulators (phantoms) that serve these purposes. The materials used in this construction were analyzed and their attenuation coefficients were compared to simulated breast tissues. The phantoms were prepared in polymethylmethacrylate molds and plates, known as acrylic, and the test structures used were microcalcifications, simulated by limestone, and fibers, simulated by nylon. The phantoms I-a and I-b are intended to perform quality control and has its test structures placed in a mixture of paraffin gel and acrylic powder and dental wax, respectively. The phantom II is intended to conduct the training of residents and radiologists and has its test structures placed in dental wax. The detectability of the test structures was variable with the thickness of phantoms. After analysis and comparison of results between the phantoms made and the marketable phantom recommended by the national standard, made phantoms were validated. / O câncer de mama é o tipo de câncer que mais atinge mulheres em todo o mundo. Sua detecção precoce é fundamental para realização do seu tratamento e, consequentemente, a redução da sua taxa de mortalidade. A mamografia é considerada a técnica mais adequada para esta detecção, que se baseia na visualização de pequenas estruturas e padrões que podem representar lesões cancerígenas. Porém, para visualização destas estruturas, o controle da qualidade das imagens mamográficas e o treinamento de residentes e radiologistas é necessário. Tendo isto em vista, este trabalho teve como objetivo o desenvolvimento e a confecção de três simuladores de mama (phantoms) que servem a estes propósitos. Os materiais utilizados nesta construção foram analisados e seus coeficientes de atenuação foram comparados aos tecidos mamários que simulam. Os phantoms foram confeccionados em moldes e placas de polimetilmetacrilato, conhecido como acrílico, e as estruturas de teste utilizadas foram as microcalcificações, simuladas por calcário, e as fibras, simuladas por nylon. Os phantoms I-a e I-b têm o propósito de realizar o controle de qualidade e possuem suas estruturas de teste inseridas em uma mistura de parafina em gel e acrílico em pó e cera, respectivamente. O phantom II tem o propósito de realizar o treinamento de residentes e radiologistas e possui suas estruturas de teste inseridas em cera de uso odontológico. A detectabilidade das estruturas de teste se mostrou variável com as espessuras dos phantoms. Após análise e comparação dos resultados entre os phantoms confeccionados e o phantom comercial recomendado pela norma nacional, os phantoms confeccionados foram validados.

Zahlreiche chirurgische Assistenzsysteme sind in der klinischen Praxis im Einsatz, um die Genauigkeit und Sicherheit medizinischer Eingriffe zu erhöhen. Die Verwendung von Bildgebungsverfahren durch solche Systeme und die Teilautomatisierung von Prozessen kann einen weiteren Schritt in Richtung höherer Effizienz chirurgischer Interventionen und höherer Patientensicherheit darstellen. Dies stellt jedoch große Herausforderungen an die Systementwickler, welche zur Evaluation dieser Systeme während der Konstruktion geeignete Konzepte und Testmethoden benötigen. Diese Arbeit hat zwei wesentliche Zielsetzungen: Zum einen soll vorgestellt werden, wie zur zielführenden Entwicklung eines duplexsonographisch geführten, semiautomatisch arbeitenden Assistenzsystems zur Gefäßpräparation (ASTMA-System) ein anthropomorphes, physiologisches Phantom anhand zuvor definierter, für die Entwicklung relevanter, Anforderungen konstruiert wurde. Dieses ermöglichte es, die Arbeitsprozesse des Systems und deren Eignung bereits in vitro umfangreich zu testen. Zum andern soll dargestellt werden, wie das Phantom hinsichtlich dieser Anforderungen in einer Studie validiert wurde, um zu gewährleisten, dass dieses für die Systementwicklung erforderliche Eigenschaften aufwies. Dadurch konnten wichtige Informationen über Nutzen und Limitierung der Verwendung des Phantoms und mögliche Probleme des ASTMA-Systems gewonnen werden. Hiermit soll demonstriert werden, wie ein Entwicklungs- und Validierungsansatz für ein Phantom als Testsystem zur Entwicklung und Evaluation ähnlicher komplexer medizintechnischer Systeme mit intraoperativer Bildgebung gestaltet werden kann und welchen Anforderungen solche Phantome genügen sollten. Dies kann dabei helfen, die Systementwicklung zielführend und ressourceneffizient durchzuführen, Probleme bereits während früher Entwicklungsschritte aufzudecken und zu lösen und die Eignung des Verfahrens des entwickelten Systems zu beurteilen.

Bakgrund: Majoriteten av de personer som genomgått ett amputationsingrepp drabbas av fantomsmärta. Trots att fantomsmärta är ett vanligt fenomen inom denna patientgrupp så är det ofta missförstått och det föreligger problem förknippade med hanteringen av fantomsmärtor. Tidigare forskning har visat inkonsekventa resultat som varierar från en forskare till en annan och komplexiteten med fantomsmärta har lett till behandlingsresultat med varierande effekt. I första hand har farmakologisk behandling använts, men många patienters smärta förblir refraktär mot farmakologiska medel och kräver därför andra alternativ. En alternativ behandling som först föreslogs i början på 1990-talet i vårdandet av fantomsmärta är spegelterapi. Spegelterapi kan användas som en omvårdnadsåtgärd för att smärtlindra fantomsmärtor och ska minska den amputerade kroppsdelens smärta.Syfte: Syftet med föreliggande litteraturstudie är att belysa effekten av spegelterapi som en omvårdnadsåtgärd för smärtlindring av fantomsmärtor.Metod: Metoden som använts är systematisk databassökning i databaserna PubMed och Cinahl. Litteraturstudien baseras på 10 vetenskapliga studier med kvantitativ studiedesign.Resultat: Litteraturstudiens syfte blev besvarat och kunde fastställa att spegelterapi har en smärtlindrande effekt för fantomsmärtor. Ett bifynd var att interventionen även bidrar till enförbättrad livskvalitet. Således delades resultatet in i två huvudteman: Spegelterapins smärtlindrande effekt utifrån olika smärtskattningsskalor samt påverkan på livskvaliteten. De frågor som ställts är om spegelterapi är en omvårdnadsåtgärd som kan användas i praktiken.Konklusion: Spegelterapi har en smärtlindrande effekt och minskar fantomsmärtor. Ett bifynd var att interventionen även bidrar till en förbättrad livskvalitet samt ökar välmåendet hos amputerade personer som lider av fantomsmärtor. Spegelterapi hade kunnat användas i praktiken efter att ha blivit optimerad och där en standardmetod för spegelterapi tagits fram. Däremot krävs det vidare forskning om spegelterapi. / Background: The majority of amputees suffer from phantom pain. Although phantom pain isa common phenomenon, it is often misunderstood and there are often problems with themanagement of phantom pain. Previous research has shown inconsistent results that varyfrom one researcher to another. The complexity with phantom limb pain has led to treatmentresults with varying effects. Primarily pharmaceuticals have been the main treatment. But many patients' discomfort still remains and the need for alternative treatment options isimperative. One alternative treatment is mirror therapy which was first suggested in thebeginning of the 1990’s century. Mirror therapy is supposed to reduce the phantom limb pain.Aim: The aim of this literature review is to highlight the effect of mirror therapy as a nursing treatment for reducing phantom limb pain.Method: The method that is used is a systematic database search in PubMed and Cinahl. The literature study is based on 10 scientific articles with a quantitative study design.Result: The literature study proved that mirror therapy is effective for reducing phantom limb pain. A secondary finding was the improvement of quality of life. Therefore the result was divided into two main themes: Change in phantom pain based on different pain assessment scales and the impact on the quality of life. Questions that were asked are whether mirror therapy is an intervention that can be used in the treatment of the phenomenon.Conclusion: Mirror therapy does reduce phantom pain in amputees. A secondary finding was that the intervention also contributes to a better quality of life and increases the well-being for the amputee. Mirror therapy could be practically applied after a standard method has been produced. However, further research is needed on mirror therapy.

Chronic neuropathic pain affects up to 8% of the United Kingdom population and is a difficult condition to manage. It is established and maintained through many mechanisms, including central sensitisation (CS) in the spinal cord and brainstem. Neuropathic pain manifests as spontaneous pain, sensory loss and evoked hypersensitivity. The development of novel treatments for neuropathic pain is challenging, in part due to inadequate experimental models of clinically relevant pain. The use of functional magnetic resonance imaging (fMRI) techniques for imaging acute and increasingly tonic states enables the assessment of the neural correlates of evoked hypersensitivity and persistent pain, with the goal of developing appropriate biomarkers to test new therapies. This thesis develops novel techniques for the assessment of ongoing pain states and their modulation by therapies. We first identified a suitable human experimental model of CS using topical capsaicin, and an fMRI pipeline for the investigation of supraspinal involvement in pain hypersensitivity. In a placebo-controlled study, we then demonstrated the improved sensitivity of fMRI above subjective reports in detecting the efficacy of a known analgesic as compared to an ineffective active compound in a small cohort. To translate this to the more clinically relevant symptom of spontaneous pain, we developed and validated the use of a multi-inversion time pseudo-continuous arterial spin labelling (ASL) imaging and analysis pipeline for the neural assessment of tonic states and the absolute quantification of cerebral blood flow (CBF). Current evidence from structural and functional studies suggests a direct role for the posterior insula cortex in the encoding of nociception and pain. Using the ASL pipeline, we found that only a CBF change in the posterior insula region was correlated with the changing perception of persistent capsaicin-induced pain, and in a separate experiment showed that suppression of CBF in this region by gabapentin was related to the drug's suppression of subjective pain perception. We also demonstrated in a cohort of phantom limb patients that pain relief resulting from transcranial direct current stimulation of the deprived sensorimotor cortex is neurally represented by a decrease in posterior insula CBF. In a separate study, we showed that baseline CBF in the periaqueductal grey can predict individuals who are most vulnerable to pain and hypersensitivity following the induction of capsaicin-related CS. Taken together, these findings suggest that fMRI can be used as a tool to assess the efficacy of established and novel analgesics, with the midbrain reticular formation and posterior insula cortex being prime candidates as biomarkers of CS mechanisms and persistent pain respectively. Relatedly, ASL-fMRI may also be an effective technique for evaluating individuals' susceptibility to pain following inflammation or injury.

Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Genetic (co)variances for body weight, clean fleece weight and fibre diameter were estimated for the South African Dohne Merino using data transformed as proportions of contemporary group means. The data analysed included body weight, clean fleece weight and fibre diameter records for 282 513 animals, evaluated between 1992 and 2011. There were 5 698 sires, 105 886 dams and 6 291 contemporary groups in the data. A three-trait animal model was fitted, where the random variables were the direct additive genetic effects, as well as the sire-flock-season (SFS) interaction, while the fixed effects included contemporary groups (FYSSM) (6 291 classes), birth status (single, twins or triplets), age of dam (1 to 3 years), which was plotted as a linear regression as well as age at performance measurement, which was fitted as a polynomial. The direct heritability estimates (SE) for body weight, clean fleece weight and fibre diameter were 0.265 (0.005), 0.210 (0.004) and 0.437 (0.005), respectively. Genetic correlations for body weight with clean fleece weight and fibre diameter were 0.035 (0.015) and 0.139 (0.011), respectively, while the genetic correlation between clean fleece weight and fibre diameter was 0.169 (0.012). Body weight had phenotypic correlations of 0.327 (0.002) and 0.150 (0.002), respectively, with clean fleece weight and fibre diameter, which had a phenotypic correlation of 0.190 (0.002) with clean fleece weight. The moderate to high heritability estimates suggests that there is substantial genetic variation, which may result in genetic improvement if selection is applied on these traits. Genetic correlations were generally low, suggesting that progress in all these traits was possible in a scientific selection program. Genetic trends derived during the study supported the contention that genetic progress in all traits was attainable in a well-constructed breeding programme. Transformation of the data to percentages of contemporary groups resulted in adjustments to breeding values. The breeding values for sires originating from flocks maintained in limiting environments (Low group; 180 sires) were adjusted upwards, while those of sires originating from a non-limiting production environment (High group; 146 sires) were adjusted downwards. These effects were markedly obvious for the quantitative traits (body weight and clean fleece weight), but to a much lesser extent for fibre diameter. This transformation resulted in the genetic trends for the Low groups being adjusted to be comparable to those in the High group for body weight and Fibre diameter. It was concluded that sire breeding values derived from transformed data would be more robust across the typical diverse environments supporting local Dohne Merino production. The genetic value of animals entering the recorded population from a commercial base (F4 animals) was below the fully recorded part of the population. The inclusion of phantom parent groups in the genetic analysis rendered genetic trends in F4 animals comparable to that of the pedigreed portion of animals in the analyses. It was concluded that animals from a commercial base (which are alleged to have advantages in terms of fitness and robustness) were more likely to perform satisfactorily for selection with the inclusion of phantom groups than without it. It was recommended that data in the national Dohne Merino analysis be transformed proportion of contemporary group means to account for heterogeneous contemporary group variances. Phantom parent groups should also be applied to the analysis to increase the probability of those animals entering the breeding flock from a commercial base being selected. / AFRIKAANSE OPSOMMING: Genetiese kovariansies vir liggaamgewig, skoonvaggewig en veseldikte is vir die SA Dohne Merino bevolking in Suid-Afrika beraam nadat data getransformeer as ‘n proporsie van die kontemporêre groep gemiddelddes uitgedruk is. Die data het rekords in van liggaamsgewig, skoonvaggewig en veseldikte van 282 513 diere oor die tydperk van 1992 tot 2011 ingesluit. Die data sluit rekords van 5 698 vaars, 105 886 moers en 6 291 kontemporêre groepe in. 'n Meer-eienskapdieremodel met 'n additiewe diere-effekte sowel as 'n vaar-kudde-seisoen (SFS) interaksie is as ewekansige effekte gemodelleer, bykomstig tot die vaste effekte van kontemporêre groep (FYSSM) (6 291 klasse), geboortestatus (enkelling, tweeling of drieling), ouderdom van moer (1 tot 3 jaar) gepas as 'n lineêre regressive, sowel as ouderdom by prestasie meting as ‘n polinoom gepas. Die beraamde direkte oorerflikheid (SF) van liggaamgewig, skoonvaggewig en veseldikte van die meereienskap dieremodel was onderskeidelik 0,265 (0,005), 0,210 (0,004) en 0,437 (0,005). Die genetiese korrelasies van liggaamsgewig met skoonvaggewig en veseldikte was 0,035 (0.015) en 0,139 (0.011) onderskeidelik, terwyl die genetiese korrelasie tussen skoonvaggewig en veseldikte 0,169 (0.012) beloop het. Liggaamsgewig het onderskeie fenotipiese korrelasies van 0,327 (0.002) en 0.150 (0.002) met skoonvaggewig en veseldikte gehad, terwyl skoonvaggewig ‘n fenotipiese korrelasie van 0.190 (0.002) met veseldikte gehad het. Die medium tot hoë oorerflikheidhede dui daarop dat daar aansienlike genetiese variasie voorkom, wat kan aanleiding gee tot genetiese vordering as seleksie op die eienskappe toegepas word. Genetiese korrelasies was oor die algemeen laag wat daarop dui dat vordering in al die eienskappe deur ‘n wetenskaplike seleksie program moontlik is. Die aanspraak is deur genetiese tendense in die studie bevestig. Die transformasie van data na proporsies van kontemporêre groep gemiddeldes het daartoe gelei dat teelwaardes aangepas word. Die teelwaardes van vaars uit kuddes met ‘n omgewing wat beperk word (Lae groep:180 vaars), is opwaarts aangepas. Daarenteen is vaars uit 'n nie-beperkende produksie omgewing (Hoë groep:146 vaars) se teelwaardes afwaarts aangepas. Hierdie effekte was veral ooglopend vir die kwantitatiewe eienskappe, liggaamgewig en skoonvaggewig, maar tot 'n mindere mate vir veseldikte. Die transformasie het daartoe gelei dat die genetiese tendense for die Lae groep aangepas word om vergelykbaar te wees met die Hoë groep vir liggaamsgewig en skoonvaggewig. Die gevolgtrekking was gemaak dat meer toepaslike vaar teelwaardes, bereken vanaf getransformeerde data, verkry word vir regoor die diverse omgewings wat produksie van plaaslike Dohne Merinos ondersteun. Die genetiese waarde van diere wat die aangetekende populasie uit ‘n kommersiële agtergrond (F4 diere) binnekom was laer as die volledig aangetekende gedeelte van die populasie. Die insluiting van skimgroepe in die genetiese ontleding het tot genetiese tendense gelei wat die F4 diere vergelykbaar gemaak het met diere in die ontleding wat wel stamboekinligting het. Die gevolgtrekking is gemaak dat diere van ‘n kommersiële agtergrond (wat aanvaar word om voordele in te hou in terme van fiksheid en robuustheid) meer geredelik geselekteer sal word vir die stoet met die insluiting van skimgroepe as daarsonder. Dit word aanbeveel dat die data in die Nasionale Dohne Merino na proporsies van die kontemporêre groepgemiddeldes getrensformeer word om vir heterogene kontemporêre groep variansies voorsiening te maak. Skimgroepe moet ook gepas word in die ontleding om die waarskynlikheid te verhoog dat diere vanuit 'n kommersiële basis, ook geselekteer sal word.

<p>Threats from man-made radionuclides include waste issues, increasing number of power plants, underground bomb testing, nuclear weapons, and “dirty bombs”. Until recently the ionizing radiation protection system focused on protecting humans with an implied protection of biota. However, goals of sustainable development and precautionary principles for human activity are leading to an inclusion of plant and animal populations in the protection system.</p><p>From this perspective, the present thesis examines wetlands that function as sinks for the radionuclide 137Cs, and describes calculated and measured radiation doses to residing biota. Also, multi-level effects from exposure to low-dose rate ionizing radiation were studied. Accumulation of 137Cs after the Chernobyl accident fallout was studied in a riparian wetland with a mean activity concentration of 1 200 kBq m-2 in Sweden (paper I). A mass balance budget of 137Cs showed that the sedimentation of new material was balanced by the decay process of 137Cs in parts of the wetland (paper I).</p><p>Frogs were identified as organisms of concern in this wetland. Internal radiation doses, based on whole body measurements of frogs, were estimated to be lower than external doses based on soil samples (paper II). Current dose models for biota resulted in a wide range of doses depending on different levels of conservatism in the models. Therefore, in situ measurements with frog-phantoms were found to provide valuable dose information (paper III). Measured doses using frog-phantoms were lower than calculated doses using several dose models. Although a dose conversion factor by FASSET was found to be useful for comparison with measurements in the field. A higher dose was measured to the phantom surface in comparison to inner parts, i.e. the sensitive skin of frogs receives the highest dose. Estimated and measured radiation doses to frogs were below suggested dose rate limits.</p><p>Low-dose rate 137Cs exposure of eggs and tadpoles from three amphibian species, Scaphiopus holbrookii, Bufo terrestris, and Rana catesbeiana, showed no increased levels of strand breaks in red blood cells, and no effects on development, survival or growth up to metamorphosis (paper IV). The ecological factor larval density had a stronger effect on metamorphic traits than low-dose rate radiation. Higher levels of strand breaks were detected after an acute dose in R. catesbeiana than after a chronic dose supporting a dose rate limit for protection of amphibians rather than a dose limit (paper IV).</p><p>Based on current knowledge, frogs in the contaminated wetland are probably not exposed to radiation doses from 137Cs that are harmful for the population. However, variations in sensitivity between populations and species, and adaptive responses have been shown for amphibians exposed to other stressors. This supports further research on effects of chronic low-dose rates of ionizing radiation on amphibians.</p>