Neste trabalho estudamos as singularidades de projeções no plano de curvas genéricas, introduzindo uma nova relação de equivalência para germes e multigermes de curvas planas, denominada A_h-equivalência. / In this work singularities of projections to the plane of curves are studied. We introduce a new equivalence relation for germs of plane curves, called A_h-equivalence.

O comportamento do escoamento supersônico no interior de bocais convergente-divergente retangulares é investigado numericamente, comparando-se quatro bocais com diferentes seções divergentes, com a mesma razão de aspecto AR=1.14 e mesma relação áreas da saída e da garganta dos bocais NAR=1.43. Os bocais são submetidos a diferentes pressões de admissão do fluido de trabalho, mantendo-se a relação entre a pressão de admissão e de descarga constante NPR=5. As simulações consideram o escoamento em regime permanente, compressível, viscoso, com abordagem baseada na massa específica (abordagem acoplada) , juntamente com o modelo de turbulência − /SST. A qualidade dos resultados é medida empregando-se três níveis de refino da discretização do domínio computacional, observandose a ordem de convergência e o índice de convergência de malhas GCI. Os resultados numéricos mostram que o número de Mach e a temperatura do fluido de trabalho independem da pressão de admissão, ao contrário do comportamento da pressão local e da massa específica. As propriedades do escoamento são fortemente dependentes da variação da geometria, e a variação do ângulo da seção divergente provoca uma mudança direta do número de Mach e inversa da pressão, da temperatura e da massa específica do escoamento no interior dessa seção. As simulações são comparadas com os resultados da teoria isentrópica e mostram que a linha sônica é deslocada do centro geométrico da garganta dos bocais para cada geometria simulada. A comparação com a teoria e com dados experimentais mostra desvios inferiores a 6x10-3 %. O uso do modelo de turbulência − / SST é capaz de resolver o escoamento com boa precisão, prevendo bem seu perfil de velocidades, as ondas de expansão de Prandtl-Meyer, juntamente com as interações dessas ondas com a camada limite. / The behavior of the supersonic flow inside rectangular convergent-divergent nozzle is investigated numerically by comparing four nozzles with different divergent sections, with a common aspect ratio AR=1.14, and the same nozzle exit-to-throat area ratios NAR=1.43. Nozzles are subject to several working fluid inlet pressures, maintaining a constant pressure ratio NPR=5. Simulations assume the flow in steady state, compressible, viscous, using a coupled approach with the turbulence model − /SST. The quality of results is measured by employing three refining levels of the computational domain discretization, observing the order of convergence and the grid convergence index GCI. Numerical results show that the Mach number and the temperature of the working fluid are independent of the inlet pressure, unlike the behavior of local pressure and the density. Flow properties are strongly dependent on the geometry variation, and the change on the angle of divergent section causes a direct effect on the Mach number and inverse on the pressure, the temperature and the density of the flow in this section. Simulations are compared to the results of the isentropic theory and show that the sonic line is offset from the geometric center of the throat nozzle, for each simulated geometry. Results from this work are compared to experimental and theoretical data and show deviations below 6x10-3 %. The − / SST turbulence model is able to solve the flow with good accuracy, and predicts its velocity profile, Prandtl-Meyer expansion waves, and their interactions with the boundary layer.

O planejamento tático da produção é importante para as organizações pois permite um correto dimensionamento dos recursos produtivos, para garantir um atendimento adequado da demanda, e influencia nas decisões de produção em médio prazo buscando soluções que colaborem positivamente no resultado operacional. O objetivo deste trabalho é o desenvolvimento de um modelo de planejamento agregado da produção para aplicação na indústria da carne suína que contemple simultaneamente as atividades finais da produção agropecuária e o ambiente de produção da indústria frigorífica. O modelo proposto contempla um sistema produtivo em dois estágios onde o primeiro estágio apresenta um fluxo divergente de produção envolvendo coprodução e o segundo estágio consiste em uma linha de montagem. O sistema apresentado é composto por uma sequência de rotinas de programação, utilizadas para a geração dos dados de entrada e um modelo matemático baseado em programação linear inteira mista cuja função objetivo é maximizar a margem global. As rotinas para geração de dados de entradas foram programadas em Visual Basic For Application e chamadas de Programa de Geração de Padrões. O modelo de programação matemática foi implementado no software LINGO e suas interfaces com as planilhas do Microsoft Excel. A aplicação do modelo para verificação utilizou dados adaptados de uma empresa envolvida no setor e os resultados obtidos permitiram testar a consistência do modelo para a situação específica. A análise dos resultados demonstrou que o modelo gera soluções que estão alinhadas com os objetivos da organização e responde adequadamente a variações nos dados de entrada. / The tactical planning activities are very important for an organization since it allows an anticipated administration of production resources in order to meet the demand and also because it suggests medium term production decisions that can contribute positively to the operational results of the company. This work aims to develop an aggregate production planning model for the pork industry which takes into consideration factors in the meat processing plant as well as in the final step of farming activities. The presented model approaches a two stage production system where the first stage is characterized by a divergent production flow involving coproduction and the second stange is an assemblage line. The entire system is composed by a sequence of routines used to generate some parameters and a mathematical formulation based on mixed integer linear programming in which the objective function aims to maximize the global margin of the organization. The routines used to generate the parameters where implemented in Visual Basic for Application and were called Pattern Generation Program and the mathematic programming were implemented in LINGO and its interfaces with worksheets of Microsoft Excel. The verification of the model used adapted data from a real company in this industry and could test its consistency for this specific situation. The analyzed results demonstrated that the model generates good solution that contribute to the global objective of the company and the model results response to the changes in the parameter as expected.

In western societies, skin cancer incidence has increased dramatically over recent decades, due predominantly to increased sun exposure habits. Ultraviolet (UV) light exposure and individual light sensitivity of the skin constitute two important factors affecting the risk for skin cancer development. Individuals with a heightened propensity to get sunburnt have a higher risk for skin malignancies, and need to protect themselves more systematically from the sun. Individual UVlight sensitivity can be determined either by self-estimation of tendency to burn and tan, as in the Fitzpatrick’s classification, or by use of a phototest. Although phototesting constitutes a considerably more objective method, it is only sparsely used, chiefly due to financial and resource related factors, and is mainly limited to investigation of photodermatoses or dose-management in photo therapy. The general aim of this thesis was to develop and improve aspects of the phototest procedure in rder to broaden the utilisation of phototesting within the fields of research, clinical practice and skin cancer prevention. As a first step, a new phototesting technique, using a divergent UVB beam was evaluated. The principle of the method is to provoke a circular UVB-erythema in the skin, the diameter of which is related to the administered dose and thus the Minimal Erythema Dose (MED). In a test group of healthy subjects, naked eye reading by a trained observer resulted in a more exact, estimation of UVB-sensitivity, compared to traditional phototesting. Since the diffuse border of the provoked erythema was challenging for the untrained observer to read, the need for an objective, bio-engineering technique for test reading was clear. In this thesis, Laser Doppler perfusion imaging (LDPI) has been used. This data also enabled an objective description of doseresponse for the reaction, an outcome not possible in traditional testing. The divergent beam method was also shown to be useful as a model for evaluation of the effect of topically applied substances. In order to broaden the utilisation of phototests in general, a test procedure built on patient performed self-reading of skin tests (a traditional phototest and an irritant patch test) was evaluated. The reliability of these self-readings was shown to be substantial when compared to the control readings of a trained observer. Using the self-reporting procedure, phototesting was evaluated as a tool in primary prevention of skin cancer. The study focussed on sun habits and sun protection behaviour, and also on investigating the impact of different forms of presentation of the preventive information. Results showed significantly higher impact for a personally mediated preventive message than by letterform. For individuals with heightened UV-sensitivity the performance of a phototest led to a greater tendency to adopt sun protection behaviour than for subjects with a lower UV-sensitivity, suggesting that phototesting is a useful way to improve the outcome in terms of preventive behaviours for this group of susceptible, at-risk individuals. Divergent beam phototesting, patient-performed self-reading, and the application of phototesting in skin cancer prevention emerge as three novel, previously little investigated, aspects of phototesting, for which promising results could be demonstrated. / Under de senaste årtiondena har insjuknandet i hudcancer ökat dramatiskt i västvärlden, detta till stor del beroende på förändrade solvanor. Exponering för solens ultravioletta strålning (UVstrålning) samt den individuella ljuskänsligheten i huden utgör två viktiga faktorer av betydelse för uppkomsten av hudcancer. Individer med ökad benägenhet att bli rödbrända i solen löper också ökad risk för hudcancer av solexponering, och behöver således vara extra noga med att skydda sig mot solen. Hur känslig man är mot solljuset kan bedömas antingen genom självskattning (klassificering enligt Fitzpatrick), eller genom att använda ett ljustest. Det sistnämnda är en betydligt mer objektiv metod, men används ändå relativt sparsamt, sannolikt ofta beroende på brist på resurser, tid eller klinisk rutin. Det övergripande syftet med avhandlingen var att utveckla och förbättra aspekter på ljustestningsförfarandet med inriktning på att kunna bredda användningen av ljustest inom forskning, klinisk verksamhet och hudcancerprevention. Som ett första steg undersöktes och utvärderades en ny ljustestteknik, baserad på en divergent (spridd) UV-stråle. Genom att belysa huden med ett cirkulärt UV-ljusfält framkallas en cirkulär rodnad (erytem), där diametern på rodnaden står i relation till den individuella ljuskänsligheten i huden. I jämförelse med traditionell ljustestningsmetodik visade sig metoden resultera i en noggrannare uppskattning av ljuskänslighet, samt möjligheten att beskriva ett dos-responsförhållande inom det rodnade hudområdet. Eftersom kanten på den framkallade rodnaden tenderade att bli ganska diffust avgränsad framkom dock, med undantag för speciellt tränade avläsare, svårigheter att läsa av testet med enbart ögats hjälp. Av den anledningen krävdes mer objektiv, hudfysiologisk mätmetodik. I de genomförda studierna användes så kallad Laser Doppler perfusion imaging (LDPI) för detta. Förutom uppskattning av ljuskänsligheten testades den divergenta UV-strålen också som modell för skattning av anti-inflammatorisk effekt av ämnen som appliceras på huden, exempelvis cortison, och visade sig användbar för detta. I syfte att öka förutsättningarna för bredare användning av ljustest, genomfördes en studie där försökspersonerna själva fick avläsa ett traditionellt ljustest och rapportera in testresultatet. Resultaten jämfördes med avläsningar utförda av en kunnig avläsare, och visade på god tillförlitlighet. Slutligen, med hjälp av den beskrivna självavläsningsproceduren, undersöktes i en primärvårdspopulation, om ljustestning kan vara användbart för att förebygga hudcancer, med inriktning på att påverka individers solvanor, solskyddsbeteende och attityder gentemot solning. I studien jämfördes även olika modeller för att presentera ett preventionsbudskap, och där ett muntligt sådant, förmedlat vid ett läkarbesök, hade ett betydligt bättre genomslag än motsvarande, enbart skriftlig, information. För individer med hög ljuskänslighet bidrog ljustestet till ökat solskyddsbeteende, vilket indikerar att ljustest skulle kunna vara ett användbart verktyg i eftersträvan att förebygga hudcancer speciellt i denna grupp av individer med förhöjd hudcancerrisk. Sammanfattningsvis utgör ljustestning med divergent UV-stråle, självavläsning av ljustest samt användning av ljustest vid hudcancerprevention tre nya, tidigare sparsamt undersökta aspekter på ljustestning, för vilka den här avhandlingen visar lovande resultat.

There is considerable evidence that pollinator shifts can explain many differences in flower morphology between closely related plant species, but the extent to which pollinator shifts can explain the maintenance of among-population variation in floral traits within species is poorly known. In this thesis, I combined comparative and experimental approaches to examine the evolution of floral traits in the moth-pollinated orchid Platanthera bifolia. More specifically, I investigated (1) the relationship between flower and pollinator morphology, (2) phenotypic selection on morphology and phenology in populations in contrasting environments, (3) components of prezygotic reproductive isolation among divergent populations, and (4) the adaptive and functional significance of two correlated floral traits. A study of Scandinavian of P. bifolia populations revealed that spur length was positively correlated with proboscis length of local pollinators, which suggests that variation in spur length reflects adaptive evolution in response to geographically variable pollinator-mediated selection. A phenotypic selection study on Öland, SE Sweden, suggested that disruptive selection on spur length contributes to the maintenance of a bimodal distribution of spur length in mixed habitats, but provided very limited evidence of divergent selection on plant morphology and flowering phenology in grassland and woodland habitats. Field experiments revealed strong reproductive isolation between divergent populations on Öland, due to differences in spatial distribution, flowering phenology, and pollinators, and among-population incompatibility. The results suggest that prezygotic reproductive isolation contributes to the maintenance of population differentiation in floral traits in P. bifolia. A field manipulation experiment demonstrated that spur length but not perianth size affects pollination success and seed production. This suggests that among-population differentiation in perianth size may be the result of a genetic correlation with spur length. Taken together, the results of this thesis suggest that pollinator-mediated selection can shape the evolution of intraspecific floral variation.

This thesis investigates the relationship between creative potential and the rhetorical structure of children&rsquo / s narratives. 44 middle school children (aged 12-15) were given a set of paper-pen activities including one divergent thinking test, one convergent thinking test and a story to be completed. Results of the divergent and convergent thinking tests were taken as the predictors to estimate the potential for creative thinking. Children were examined in terms of how they encode rhetorical relations in their writings. Whether a creative potential made a difference in children&rsquo / s writings in terms of rhetorical relations they used, and whether children within the same creative potential group used the same rhetorical relations in common were investigated. Rhetorical Structure Theory (RST) (Marcu, 2000 and Carlson and Marcu, 2001) was used in coding children&rsquo / s writings. It was found that children in the study interpreted story writing as an act of attribution. This result is contrary to Marcu et.al (1999b), who found the elaboration-additional relation as the most frequent relation in their corpora. The study also found that there was an inverse relationship between the convergent thinking scores and the number of satellites (an EDU (elementary discourse unit) playing an auxilliary role for a text in question) for the 7th graders. Finally, it was found that high quartile (highest scorers in the study, top 25%) convergent thinkers were able to construct a narrative element with few number of EDUs and few number of discourse relation types.

As individuals and populations diverge ecologically, they become exposed to new parasites and pathogens with potentially harmful fitness consequences. Populations are therefore expected to evolve resistance, possibly at a cost of less resistance to parasites rarely encountered parasites. This trade-off in resistance should generate local adaptation to parasites in different habitats. In chapter one, I show how local adaptation can potentially evolve in response to variation in parasite exposure among eighteen ecologically variable populations of threespine stickleback (Gasterosteus aculeatus). Within populations infection appeared to reflect morphology/diet based exposure differences among individuals. Among populations, however, these patterns were absent or reversed, consistent with the evolution of local adaptation. In chapters two and three I set out to test whether variation major histocompatibility (MHC) genes can underly such local adaptation in stickleback. MHC genes are important components of vertebrate immunity; however, there is little direct empirical support for spatially divergent selection driving local adaptation on MHC loci in the wild. In chapter two I tested for the action of parasite mediated balancing and divergent selection on on MHC loci using naturally infected stickleback in three replicate lake-stream pairs. Despite consistent divergence in parasites and MHC alleles, lakes tended to show decreased parasite burdens with increased allelic richness (consistent with balancing selection), while streams showed some support for divergent selection between lake and stream types. In chapter three I use the same lake-stream pairs to investigate how divergent selection could instead be reflected in variation in the effects of individual MHC alleles among populations. When comparing parapatric populations experiencing gene flow, MHC alleles maintained at relatively high frequency in one population were more likely to be associated with reduced, rather than increased, parasite abundances in that population. Allopatric populations experiencing no gene flow showed no such general relationship between allele frequency and resistance. These results are only consistent with spatially divergent selection, and imply that gene flow and environmental heterogeneity can be important for maintaining MHC diversity. / text

Alcohol dependence (alcoholism) is a complex disease influenced by both environmental factors and genetic predisposition. Mouse models have been used to study many alcohol dependence-related traits and the genetics that underlie them. Two of the most commonly used mice in alcohol research are the C57BL/6J (B6) and DBA/2J (D2) inbred strains, which diverge on several alcohol-related traits including the development of acute physical dependence. Here we utilized the B6 and D2 mice as a genetic model of acute physical dependence, coupled with mRNA Differential Display (DD) and cDNA microarray analysis, to uncover the transcriptional response of the brain to an acute dose of alcohol as a function of time. About 150 genetically divergent and alcohol-responsive genes were identified between the whole brains of B6 and D2 mice using DD and were added as additional targets to the mouse microarrays. Microarray analysis of the prefrontal cortex of B6 and D2 mice revealed strain-specific, acute alcohol-responsive transcriptome remodeling manifested as temporal patterns of gene expression. Distinct expression patterns were identified for physiologically relevant alcohol-related consequences including intoxication, withdrawal and neuroadaptation. In silico characterization of the differentially expressed genes showed genotype dependent and independent transcriptional regulation and functional classification. In addition, categorization of differentially expressed genes by their cellular profiles revealed that some of the genes were known to be more highly expressed in either excitatory or inhibitory neuronal cell types. Our results indicate that the B6 and D2 prefrontal cortices have very different cellular and molecular responses to acute alcohol exposure. The specific roles that the genes identified in this study may play in mediating the divergent alcohol-related behavior between the strains warrant further study. / text

This study developed a Methodology for the systematic and strategic fostering of creativity in graphic design education at university level. The thesis identified four social-psychological factors that have an effect on graphic design students' creative ability, namely their level of intrinsic motivation for creative activities; their ability to maintain autonomous, self-regulative behaviour that is conducive to creativity; a healthy self-belief in their creative ability and the minimization of negative stress in the educational milieu where creative tasks are undertaken. Each of these factors imply a range of strategies that may be used to maintain and stimulate creativity in graphic design education, such as the use of certain types of feedback, evaluation procedures that supports creativity, the creation of a safe, democratic, non-controlling classroom climate or the deliberate use of music and humoristic activities in the educational milieu. Additionally, a range of cognitive strategies that may be used for idea generation in graphic design are proposed. They include divergent thinking techniques, such as 'Random Association'; 'Morphological Synthesis'; 'Metaphors and Analogies'; 'Mind-mapping'; 'Idea Checklist'; 'Visual Thinking' and 'Sense Connections'. Each technique is described in terms of its unique methodology, advantages, creative potential and its applicability to graphic design. The study also proposes a tactical approach to the creative process, suggesting various cognitive strategies that may be used for each phase of the creative process. These strategies ensure that the whole spectrum of cognitive activities required for the successful production of a creative product is executed. The sum of these cognitive and social-psychological strategies provided the basis for the development -of two theoretical constructs that may be implemented as part of an undergraduate graphic design curriculum to cultivate creativity in students. They are: (1) a Learning Program in Creativity studies that consists of a number of study units and aims to provide tuition in the theoretical foundation that students need to enhance their creative ability (2) a range of General Guidelines that aim to provide educators with a range of didactic strategies and practices to support and stimulate creative ability in graphic design students. / Thesis (Ph.D. (History of Arts))--North-West University, Potchefstroom Campus, 2006.

This study developed a Methodology for the systematic and strategic fostering of creativity in graphic design education at university level. The thesis identified four social-psychological factors that have an effect on graphic design students' creative ability, namely their level of intrinsic motivation for creative activities; their ability to maintain autonomous, self-regulative behaviour that is conducive to creativity; a healthy self-belief in their creative ability and the minimization of negative stress in the educational milieu where creative tasks are undertaken. Each of these factors imply a range of strategies that may be used to maintain and stimulate creativity in graphic design education, such as the use of certain types of feedback, evaluation procedures that supports creativity, the creation of a safe, democratic, non-controlling classroom climate or the deliberate use of music and humoristic activities in the educational milieu. Additionally, a range of cognitive strategies that may be used for idea generation in graphic design are proposed. They include divergent thinking techniques, such as 'Random Association'; 'Morphological Synthesis'; 'Metaphors and Analogies'; 'Mind-mapping'; 'Idea Checklist'; 'Visual Thinking' and 'Sense Connections'. Each technique is described in terms of its unique methodology, advantages, creative potential and its applicability to graphic design. The study also proposes a tactical approach to the creative process, suggesting various cognitive strategies that may be used for each phase of the creative process. These strategies ensure that the whole spectrum of cognitive activities required for the successful production of a creative product is executed. The sum of these cognitive and social-psychological strategies provided the basis for the development -of two theoretical constructs that may be implemented as part of an undergraduate graphic design curriculum to cultivate creativity in students. They are: (1) a Learning Program in Creativity studies that consists of a number of study units and aims to provide tuition in the theoretical foundation that students need to enhance their creative ability (2) a range of General Guidelines that aim to provide educators with a range of didactic strategies and practices to support and stimulate creative ability in graphic design students. / Thesis (Ph.D. (History of Arts))--North-West University, Potchefstroom Campus, 2006.