The thesis presents a pragmatic analysis focused on the communication of twins from the 35th to the 37th month of their life in different communicative situations. The paper is based on a case study of twins. The theoretical part of the thesis is based on texts on language acquisition and communication of 3-year-old children and acquisition of pragmatics. The material for the analysis comprises of audiovisual recordings made with informed consent from the parents of the twins who were further supplemented by information obtained through parental questionnaires and interviews with the parents. Video recordings are transcribed according to the principles of CHAT of CHILDES corpus. The material is analyzed in terms of means that the children use to express communication plans. The results of the analysis are compared with the results from the theoretical part. Keywords Child speech, child language, communication, twins

The objective of this thesis is to improve the understanding of how several individual characteristics, namely education (years of schooling), health indicators (height, weight, smoking, alcohol consumption, and exercise), criminal behavior, and crime victimization, influence labor market outcomes in the short and long run. The first part of the thesis consists of three studies in which I adopt a within-twin-pair difference approach to analyze how education, health indicators, and earnings are associated with each other over the life cycle. The second part of the thesis includes two studies in which I use field experiments in order to test the employability of exoffenders and crime victims. The first essay, Learning for life?, describes an analysis of the education premium in earnings and health-related behaviors throughout adulthood among twins. The results show that the education premium in earnings, net of genetic inheritance, is rather small over the life cycle but increases with the level of education. The results also show that the education premium in health-related behaviors is mainly concentrated on smoking habits. The influences of education on earnings and health-related behaviors seem to work independently of each other, and there are no signs that health-related behaviors influence the education premium in earnings or vice versa. The second essay, Blowing up money?, details an analysis of the association between smoking and earnings in two different historical social contexts in Sweden: the 1970s and the 2000s. I also consider possible differences in this association in the short and long run as well as between the sexes. The results show that the earnings penalty for smoking is much stronger in the 2000s as compared to the 1970s (for both sexes) and that it is larger in the long run as compared to the short run (for men). The third essay, Two by two, inch by inch, describes an analysis of the height premium among Swedish twins. The results show that the height premium is relatively constant over the life cycle and that it is larger below median height for men and above median height for young women. The estimates are similar for monozygotic and dizygotic twins, indicating that environmentally and genetically induced height differences are similarly associated with earnings over the life cycle. The fourth essay, The employability of ex-offenders, published in IZA Journal of Labor Policy (2017), 6:6, details an analysis of whether male and female exoffenders are discriminated against when applying for jobs in the Swedish labor market. The results show that employers do discriminate against exoffenders but that the degree of discrimination varies across occupations. Discrimination against ex-offenders is pronounced in female-dominated and high-skilled occupations. The magnitude of discrimination against exoffenders does not vary by applicants’ sex. The fifth essay, Victimized twice?, describes an analysis of whether male and female crime victims are discriminated against when applying for jobs in the Swedish labor market. This study is the first to consider potential hiring discrimination against crime victims. The results show that employers do discriminate against crime victims. The discrimination varies with the sex of the crime victim and occupational characteristics and is concentrated among high-skilled jobs for female crime victims and among femaledominated jobs for male crime victims.

Le travail de cette thèse porte sur les raisons structurales derrière la formation de cristaux maclés. Ce travail ouvre une voie pour un futur développement de protocoles de synthèse afin de réduire l'occurrence de macles. La motivation de cette étude est que la présence de macles affecte négativement les propriétés physico-chimiques des matériaux d'intérêts technologiques et réduit aussi la qualité des données expérimentales sur lesquelles se fonde l'analyse structurelle. Ce dernier problème est particulièrement sensible dans le cas de cristaux ayant des paramètres de maille importantes, comme les macromolécules biologiques. Les principes de symétrie responsables du phénomène de maclage dans le cas d’une macle de transformation ou d'origine mécanique sont bien connues. En revanche dans le cas d’une macle de croissance, le maclage est toujours considéré comme un accident lié aux conditions aléatoires de croissance cristalline où à la cinétique, plutôt qu'à la thermodynamique. Une approche générale connue comme la « théorie réticulaire des macles » a été développée depuis le XIXe siècle, fondée sur l'existence d'un sous-réseau commun aux cristaux maclés, qui donne les conditions  nécessaires pour l'apparition d'une macle. Cette approche est cependant insuffisante pour déterminer la différence entre les macles avec le même degré de chevauchement des réseaux mais montrant une fréquence d'occurrence assez différente. Une approche structurale, fondée sur l'analyse de la symétrie propre des orbites cristallographiques a été proposée il y a plus d'un demi-siècle (Donnay et Curien, 1960), mais est restée à l'état embryonnaire, malgré une certaine reprise récente (Nespolo et Ferraris, 2009). En outre, l'idée qu'une interface commune aux cristaux maclés puisse contenir une opération reliant ces individus a été proposée (Holser, 1958) mais n'a jamais été portée à un plein développement. Dans cette thèse, nous présentons un développement algébrique de ces idées. Nous montrons que les conditions structurales nécessaires pour la formation d'une macle de croissance peuvent être formulées en se basant, notamment, sur la symétrie propre des orbites cristallographiques et sur le groupe sous-périodique de la couche transversale donnant la symétrie d'une couche commune. L'analyse détaillée dans cette thèse de trois macles fréquentes démontre une corrélation claire entre le degré de restauration de la structure par l'opération de maclage et la fréquence d'occurrence des macles. Un exemple négatif, à savoir une macle hypothétique dont on pourrait prévoir la formation  sur la base de la théorie réticulaire a aussi été analysé. Le fait que cette macle n'ait jamais été observée, en raison d’une faible restauration de la structure qui serait produite par l'opération de macle, confirme le bien fondé de l'approche. Nous nous attendons à ce que la généralisation de l'approche présentée dans cette thèse fournisse une procédure semi-automatique pour prévoir la probabilité de formation d'une macle. Cela permettrait aux personnes travaillant dans la synthèse cristalline démoduler la fréquence de maclage. Le procédé fait appel à la modification de la morphologie du cristal pour une plus grande exposition et le développement des faces cristallines qui présentent une interface défavorable pour le maclage. / This thesis addresses the structural rationale behind the formation of growth twins, with the purpose of opening a route to the future development of synthesis protocols to reduce the occurrence frequency of twinning. The reason for this effort is that twinning affects negatively the physico-chemical properties of materials and biomaterials of technological interests and reduces the quality of the experimental data on which the structural investigation is based. While on the one hand the reasons for twinning in transformation and mechanical twins are well understood, in the case of growth twins twinning is still seen as an accident linked to aleatory conditions where kinetics, rather than thermodynamics, plays a principal role. A general approach known as the reticular theory of twinning has been developed since the XIX century, based on the existence of a sublattice common to the twinned crystals, which gives the minimal necessary conditions for the occurrence of a twin. This approach is, however, insufficient to discriminate between twins with the same degree of lattice overlap but showing a fairly different occurrence frequency. A structural approach, based on the analysis of the eigensymmetry of the crystallographic orbits building a crystal structure was proposed more than half a century ago (Donnay and Curien, 1960) but remained at an embryonic state, despite some recent revival (Nespolo and Ferraris, 2009). Also, the idea that a slice common to the twinned individuals may contain an operation mapping these individuals was proposed (Holser, 1958) but never brought to a full development. In this thesis, we present a full development of these ideas and show that the structurally necessary conditions for the formation of a growth twin can be described on the basis of the eigensymmetry of the crystallographic orbits and on the sectional layer group giving the symmetry of the common slice. The detailed analysis of three well-know twins demonstrates a clear correlation between the degree of structural restoration by the twin operation and the occurrence frequency of the twins. The analysis of a negative example, i.e. of a hypothetical twin which one would expect on the basis of the reticular theory but has never been observed, strengthens the evidence of this correlation, because of the low structural restoration one would observe in that twin. We expect that the generalisation of the approach presented in this thesis through a semi-automatic procedure will provide crystal growers with a powerful tool to modulate the occurrence frequency of twinning through a modification of the crystal morphologies towards a larger exposure and development of crystal faces which represent an unfavorable interface for twinning.

The main goal of this thesis is the analysis of multiple-births in Czech Republic between the years of 1950 and 2005 including the international comparison and assess of the influence of assisted reproduction on occurrence of multiple-births. The thesis is divided into five different parts. The first part is dedicated to the analysis of fertility according to a succession of births in Czech Republic while using the indicators of total fertility, the average age of mothers in the time of childbirth and the total number of new-born babies. The second part focuses on multiple-births considering both historical and contemporary point of view and on possible risks for both the mother and the foetus. Next part describes the assisted reproduction, its history, present and commonly used methods. The fourth part is dedicated to the influence of assisted reproduction on the occurrence of multiple-births and to the analysis of multiple-births with the use of absolute and relative number of mono-births and multiple-births indicators, indicators of total fertility, masculinity index, the rate of stillborn babies and the proportion of children born outside of marriage. The last part compares the development of multiple-births within the European countries according to NIDI 1999 classification.

O nascimento de gêmeos na espécie humana é rodeado por muitos mistérios e, há bastante tempo, desperta a curiosidade tanto leiga quanto científica. Os estudos com gêmeos vêm contribuindo para o entendimento de diversas áreas da biologia humana; porém, aspectos epidemiológicos e etiológicos relacionados aos nascimentos gemelares em si permanecem pouco elucidados. Para além de mera curiosidade, pesquisas nessa área podem ajudar a compreender mecanismos relacionados à reprodução em geral, além de serem importantes em um contexto de saúde pública, já que a gestação gemelar representa riscos adicionais à mãe e à prole. Em países industrializados observa-se um aumento acentuado nas taxas gemelares (TGs) que parece estar relacionado ao aumento da idade materna na primeira gravidez e tecnologias de Reprodução Medicamente Assistida (RMA). No Brasil, os aspectos geográficos e sociodemográficos dos nascimentos gemelares ainda não foram profundamente estudados. Assim, este estudo objetivou responder a três questões principais relacionadas aos nascimentos de gêmeos: “Quantos?” “Onde? e “Como?”, isto é, considerando aspectos epidemiológicos e etiológicos. Para o estudo epidemiológico, desenhamos um estudo de base de dados populacional e investigamos as TGs em duas dimensões: espacial e temporal. Para isso, utilizamos dados provenientes do Sistema de Informações sobre Nascidos Vivos (SINASC) e analisamos mais de 41 milhões de nascimentos que ocorreram em todos os 5.565 municípios brasileiros entre 2001 e 2014. Encontramos uma TG nacional média de 9,41 por 1.000 nascimentos e o modelo de análise de séries temporais revelou tendência de aumento global ao longo do período estudo, mas com notáveis diferenças regionais. De fato, resultados da “Análise de Cluster e Outlier” (Anselin Local Moran’s I) revelaram concentração de municípios com altas TGs em uma área que vai do sul do Nordeste brasileiro até o Rio Grande do Sul (Global Moran Index = 0.062, P < 0.001). Além disso, encontramos correlação positiva entre o Índice de Desenvolvimento Humano (IDH) local e as TGs em diferentes cenários, sugerindo que o IDH pode ser um importante indicador de RMA no Brasil. Nossas análises também revelaram aumento de 26.42% na TG entre as mulheres com mais de 44 anos durante o período estudado. A tendência de aumento temporal encontrada para algumas regiões do país está de acordo com o que é observado em outros países industrializados, enquanto que a análise geográfica revelou duas situações bem distintas dentro do Brasil. Por sua vez, os 9 estudos acerca da etiologia dos nascimentos de gêmeos foram concentrados em investigar polimorfismos de nucleotídeo único (SNPs) em mães de Cândido Godói (CG), uma pequena cidade do Sul do Brasil conhecida como a “Cidade dos Gêmeos”. Este título é devido à alta TG observada no município e à recorrência do traço nas famílias locais, com forte descendência europeia. Nós desenhamos um estudo caso-controle e genotipamos sete SNPs relacionados à foliculogênese (rs6166:C>T em FSHR, rs11031006:G>A próximo a FSHB, e rs17293443:T>C in SMAD3) ou a gestações de sucesso (rs1801131:T>G e rs1801133:G>A em MTHFR, rs2010963:C>G em VEGFA, e rs1800629:G>A em TNF) em 44 mães de gêmeos (casos) e 102 mães de filhos únicos (controles), todas residentes de CG. Para todos os SNPs, a distribuição das frequências alélicas e genotípicas foi similar entre casos e controles. Diferentes combinações de alelos de risco e análises haplotípicas também foram homogeneamente distribuídas entre ambos os grupos. Assim, estes resultados sugerem uma ausência de associação entre os nascimentos gemelares em CG e sete SNPs relacionados à foliculogênese ou a gestações de sucesso, mas é possível que outras variantes genéticas ligadas a ambos os processos possam estar envolvidas neste fenômeno que possui uma base genética subjacente. / The birth of twins in human species is surrounded by many mysteries and it has long aroused both lay and scientific curiosity. Studies with twins have contributed to the understanding of several areas of human biology; however, the epidemiological and etiological aspects related to twin births by themselves remain unclear. Beyond mere curiosity, research in this field may help us to understand the mechanisms related to reproduction in general, and it is important in a public health context since a twin pregnancy represents additional risks to the mother and offspring. Some countries have reported a striking increase in twinning rates (TRs), which seems to be related mainly to delayed childbearing and to Medically-Assisted Reproduction (MAR) technologies. In Brazil, the epidemiological scenario of twin births has not been studied while considering its territorial and sociodemographic magnitude. Therefore, this study aimed to answer three main questions related to twin births: "How many?", “Where” and "How?", that is, we investigated twinning in light of epidemiology and etiology. For the epidemiological study, we carried out a population-based study, investigating twin births in two dimensions: spatial and temporal. For that, we used data from Brazil’s Live Birth Information System (SINASC), and we analyzed over 41 million births that occurred in all 5,565 Brazilian municipalities between 2001 and 2014. We found an average TR of 9.41 per 1,000, and a first-order autoregressive model of time-series analysis revealed a global upward trend over time, but with important regional differences. In fact, a Cluster and Outlier Analysis (Anselin Local Moran’s I) was performed and identified clusters of high TR in an area stretching from the south of Brazil’s Northeast Region to the South Region (Global Moran Index = 0.062, P < 0.001). Furthermore, we found a positive correlation between the local Human Development Index (HDI) and TRs in different scenarios, suggesting that the HDI may be an important proxy indicator of MAR in Brazil. We also found a sharp increase (26.42%) in TR in women aged over 44 years. The upward temporal trend in TRs is in line with recent observations from other countries, whereas the spatial analysis revealed two very different realities within our country. In turn, studies on the etiology of twin births were focused on single nucleotide polymorphisms (SNPs) in mothers from Cândido Godói (CG), a small southern Brazilian city known as the "Twin’s Town”. This title is due to the high TR attributed to the municipality and to the recurrence of the twin trait through the 11 local families, who have a strong European descent. We performed a case-control study and genotyped seven SNPs related to folliculogenesis (rs6166:C>T in FSHR, rs11031006:G>A near FSHB, and rs17293443:T>C in SMAD3) and to a successful pregnancy (rs1801131:T>G and rs1801133:G>A in MTHFR, rs2010963:C>G in VEGFA, and rs1800629:G>A in TNF) in 44 mothers of twins (cases) and 102 mothers of singletons (controls), all of them from CG. For all SNPs, the distributions of the genotypic and allelic frequencies were similar between the cases and controls. Different combinations of risk alleles and haplotypic analyses were also homogeneously distributed between both groups. Thus, these results suggest a lack of association between twin births in CG and seven SNPs related to folliculogenesis or successful pregnancies, but it is possible that other genetic variants linked to both processes may be involved in this phenomenon, which has an underlying genetic basis.

Detailed microstructural characterisation has been conducted in both ‘as-transformed’ and ‘hot deformed’ samples of 𝜏-MnAl-C using transmission electron microscopy. After hot deformation, true twins, dislocations, intrinsic stacking faults and precipitates of Mn3AlC are the main defects in the recrystallised grains. A significant fraction of non-recrystallised grains existed, which had microstructures based on combinations of high densities of true twins, dislocations, and deformation bands. The formation of the Mn3AlC precipitates was confirmed and related to the reduction of saturation magnetization and the increase in the Curie temperature of 𝜏-MnAl-C after hot deformation. Antiphase boundaries, which are believed to act as nucleation sites for reverse domains, were not observed in the hot deformed sample. Increasing structural disorder is expected for the tetragonal L10 𝜏-MnAl-C (c:a = 0.91) going from coherent true twin boundary to incoherent true twin boundary to the order twin boundary. This was demonstrated from the interface structure in the HAADF-HRSTEM images. The disorder at different types of twin boundaries is also associated with the degree of segregation of the constituent elements. By using STEM-EELS, higher Mn enrichment and Al deficiency was observed at the order twin boundary with a thickness about 6 nm, slightly Mn segregation was observed at incoherent true twin boundary with reduced thickness about 1.5-2 nm and no segregation was found at the coherent true twin boundary. In addition, the distribution of carbon is inhomogeneous across the twin boundary and carbon cluster was found at the twin boundary. Micromagnetic simulations and machine learning were conducted in an international collaboration with Danube University Krems, Austria, which enabled the quantification of the effect of twins on the magnetic properties of 𝜏-MnAl-C.

In the domain of social design, this thesis introduces a design project that explores a place-centric view on interaction design to address issues of participation, representation, and place. The project aims to envision possible futures of city-scaled digital twins as places that enable collective engagement within communities and between citizens and cities. It explores this aim with a methodology grounded in co-design- and ethnographic values, focusing on the place of Ringön in Gothenburg. The final design outcome of the study is an augmented reality-based application connected to the city-scaled digital twin of Gothenburg. The application introduces a concept that enables citizens to express location-based social and cultural values and engage in common concerns. It enables the City of Gothenburg to communicate with citizens and develop an enriched understanding of the identity and character of places in Gothenburg. The study hopes to contribute with knowledge to the body of work within social design that explores how sustainable smart cities can develop from a bottom-up perspective, in a more participatory and socially sustainable way.

The purpose of this study was to explore, describe and explain the transitions of individuals within a twinship from Grade R through to Grade 2, and thus offer an in-depth description of such participants’ transition experiences and perspectives. I focused my investigation on the overall transitions of the individuals within a twinship from Grade R through to Grade 2, and included variables such as stress, stressors, emotions, coping, and life skills. In this qualitative research study, I used a case study research design and conducted the research from both an interpretivist and social constructivist point of view. The primary participants in the research were two monozygotic individuals within a twinship (boys), their mother, and their Grade R, Grade 1 and Grade 2 teachers. I commenced the fieldwork when the individuals within a twinship were in Grade R and five years old, and tracked their transitions through until their Grade 2 year when they were eight years old. During their Grade R year, I taught the individuals within a twinship certain life skills by utilizing creative, age-appropriate worksheets and play activities. I continued to utilize such activities as a catalyst for collecting data throughout their Grade 1 and Grade 2 years. I also conducted semi-structured interviews with their mother and teachers. During visits to their school, I also observed the individuals within a twinship in their natural setting. The findings of the study suggest that the transition of the individuals within a twinship effected mainly trouble-free transitions from Grade R through to Grade 2 largely because of their positive attitudes and behaviour, their self-confidence, their pleasure in tackling new experiences, the security and support they enjoyed as co-individuals within a twinship, their satisfying friendships, the positive qualities of their teachers, the learned life skills, their realistic expectations of Grade 1 and Grade 2, and their ability to cope satisfactorily with their academic work. The negative stressors during these transitions were bullies and the disruption caused by disobedient children. A key finding of this study was that the transition of the individuals within a twinship to Grade 2 was, to some extent, more stressful than their transition to Grade 1 because of more demanding academic expectations in Grade 2. In spite of this, they characterized their Grade 2 holistically as enjoyable and rewarding. The learned life skills helped them to cope with various stressors, though the overall support structures of the individuals within a twinship were most influential in their largely trouble-free transitions from Grade R through to Grade 2. The learned life skills enabled the participants to deal successfully with bullies, to develop rewarding friendships, and with emotional control. It was apparent throughout this research that the individuals within a twinship enjoyed all the advantages of supportive social structures including a stable and safe home and school environment, This resulted in good relationships with each other, their parents siblings, teachers and friends. / Thesis (PhD)--University of Pretoria, 2012. / Educational Psychology / unrestricted

This thesis deals with twins in a socio-cultural perspective and the main aim is to explain, how stereotyping of twins influences the perception of twin identity in twins. The theoretical and empirical work includes a theoretical part explaining the key terms and concepts (eg. twins, history of twin studies, social perception and stereotyping of twins) and an empirical part based on a qualitative research survey, supplemented by knowledge from the theoretical part. The empirical study introduces the methodological process of the research survey and the resulting results, which comes from the analysis of interviews by ten respondents. Key words: twins, twinship, stereotyping, social perception, identity, identification

The application of high resolution electron backscatter diffraction (HR-EBSD) techniques has been used in order to study the evolution of geometrically necessary dislocation (GND). The tested materials were taken from AZ31 magnesium sheet which had strong basal texture. Because of low symmetry of the magnesium crystal lattice, the von Mises criteria cannot be satisfied by the three independent, easily activated, basal slips. The strain along the c-axis of the crystal must be accommodated by either twinning and/or slip systems. HR-EBSD data was taken in order to investigate these phenomena. The HR-EBSD results were post processed in order to resolve total GND density onto the observed possible slip systems. The first chapter of the investigation focused on the correlation between resolved GNDs with tensile twin nucleation, and the subsequent propagation path in the microstructure. For this purpose, 2.5 % strain was applied in a uniaxial compression test along the transverse direction (TD). Several fine scan were done at the boundaries where twin formed. The results show that in order for a twin to nucleate spontaneously at the grain boundaries, two criteria should generally be met: high angle grain boundaries (35-45°) and pile ups of basal slip system in neighboring grain at the other side of the boundary. Furthermore, once nucleation has initiated, twin propagation can occur through low angle grain boundaries (15-25°); if a twin reaches a high angle boundary, it will generally terminate at the boundary at low strain levels. A twin may pass through high angle boundaries with further deformation. In the second chapter, deformation of the AZ31 magnesium alloy was study for different strain paths. For this purpose, compression and tension in-situ tests were done and the texture and GND evolutions were investigated. The results show that the load paths, compression and tension, evolve the microstructure in different ways. Massive twin fractions were formed in compression, and higher GND contents were observed in tension tests. It was observed that at higher strain levels GND contents are roughly independent of the initial texture but the activation of slip systems at low strain strongly depends on initial structure. If the samples were loaded along RD, GND density increased sharply at low strain. In contrast, for the samples loaded along TD, GND increased moderately. A small amount of repetition is apparent in the two parts of the thesis due to them being formatted for individual publication as journal papers.