Le manque de connaissance sur les interactions existantes entre les adjuvants organiques et les phases minérales ainsi que leur influence sur les mécanismes d’hydratation du Ciment Portland Ordinaire (CPO) limite le développement de nouvelles molécules organiques avec des propriétés améliorées et contrôlées. Ici, le but de ces travaux était de comprendre pourquoi et comment des adjuvants organiques modifient le temps de prise du CPO en faisant varier progressivement les caractéristiques de molécules organiques simples comme leur charge, leurs groupes fonctionnels (hydroxyle, hydroxy-carboxylate, carboxylate, sulfonate et phosphonate) et la stéréochimie de leurs groupes hydroxyles.Les différents retards induits par les molécules organiques étudiées sur l’hydratation du composé minéral responsable des propriétés finales du CPO, le silicate tricalcique, ont été reliés aux caractéristiques des composés organiques. Les interactions de ces derniers dont leur adsorption sur du silicate de calcium hydraté (C-S-H) ainsi que leur complexation avec les ions calcium, hydroxyde et/ou silicates en solution ont été identifiées dans des systèmes à l’équilibre et corrélées au retard généré par les molécules organiques sur l’hydratation du silicate tricalcique.L’impact des hexitols qui varient uniquement en fonction de la stéréochimie de leurs groupes hydroxyles sur le processus de dissolution-précipitation de l’hydratation du silicate tricalcique a été étudié. L’influence de ces polyols sur l’hydratation d’un mélange luminatesulfate de calcium a été expliquée par leur adsorption sur l’ettringite, les AFm et par leur complexation ionique en solution. Pour finir, cette étude s’est focalisée sur les conséquences des interactions des hexitols avec l’ettringite et les ions aluminate en solution sur l’hydratation des phases silicates présentes dans le CPO. / The current limited knowledge on the interactions between organic admixtures and mineral phases as well as their influence on the hydration mechanisms of the Ordinary Portland Cement (OPC) represents a real limitation in the development of new organic products with improved and controlled properties. Here, this study intended to understand why and how organic admixtures modify the setting time of OPC by progressively varying the characteristics of simple organic molecules such as their charge, functional groups (hydroxyl, hydroxy-carboxylate, carboxylate, sulfonate and phosphonate) and the stereochemistry of their hydroxyl groups.The different retardations induced by the organic molecules studied on the hydration of the mineral compound responsible of the final properties of OPC, tricalcium silicate, were related to the characteristics of the organic admixtures. The interactions of these organic compounds such as their adsorption on calcium silicate hydrate (C-S-H) and their complexation with calcium, hydroxide and/or silicate ions in solution were identified in systems at equilibrium and correlated to the retarding effect generated by the organic molecules on the hydration of tricalcium silicate.The impact of hexitols which differ from one another in the stereochemistry of their hydroxyl groups on the dissolution-precipitation process of the hydration of tricalcium silicate was studied. The influence of these polyols on the hydration of a calcium aluminate and calcium sulfate mixture was explained by their adsorption on ettringite and AFm as well as by their ionic complexation in solution. Finally, this study focused on the consequences of the interactions of hexitols with ettringite and aluminate ions in solution on the hydration of the silicate phases present in OPC.

Understanding the strategies that plant populations implement to increase evolutionary responsiveness to better survive environmental changes induced by climate change is a critical challenge for ecology and evolutionary studies. This dissertation investigates the role of hybridization, local adaptation, and phenotypic plasticity in plant population responses to environmental change. Specifically, I utilized meta-analysis techniques to investigate the prevalence of local adaptation and phenotypic plasticity as the two main mechanisms used to adapt to heterogeneous environments, and experimentally explored the genetic pathway of plasticity in phenology traits such as bolting time in Arabidopsis thaliana under high temperatures. Furthermore, A. thaliana was used to create artificial hybrids to test if novel trait combinations allow hybrids to outperform their parental source in novel and stressful environments. In the second chapter, I included reciprocal transplant plant studies and found that local adaptation is more common than adaptive plasticity as an evolutionary response to environmental heterogeneity. Although local adaptation was more common, plastic responses have been reported as a mechanism to tolerate increases in global temperature; however, the underlying genetic and developmental mechanisms are only starting to be elucidated. To address this, the third chapter determined whether alternative splicing of the ambient temperature flowering pathway gene FLOWERING LOCUS-M (FLM), and expression of SHORT VEGETATIVE PHASE (SVP), can explain flowering time plasticity in ecotypes of A. thaliana under 18°C and 26°C. Although the expression of SVP and FLM-β tracks reaction norms, I failed to find evidence that alternative FLM splicing plays a role in phenotypic plasticity in intraspecific flowering time variation. Intraspecific hybridization (admixture) disrupts divergent genetic architectures between populations to generate phenotypic novelty and raw material for environmental selection to act upon. In order to understand the effect of this disruption to local adaptation of A. thaliana ecotypes separated along geographic and locally adaptive genetic distances, the fourth chapter used experimentally created F1-hybrids between geographically distant ecotypes, and used single nucleotide polymorphism (SNP) data to estimate (putatively neutral) background and adaptive genetic distances. My results suggest that disruption of locally adaptive genomic loci decreases the performance of offspring between distantly related parents, but that crosses between very closely related parents also reduce performance, suggesting that during admixture selection may have to balance the consequences of disrupting local adaption while also avoiding inbreeding depression. Lastly, I examined the effect of recombination events under limiting and novel growing conditions (i.e. drought, high temperatures, and freezing field over-wintering conditions) in A. thaliana F2-hybrids. I provide empirical data for the effect of limiting growing environment on phenology, growth, and fitness traits on the admixed and parental ecotypes. I found that recombination events generate novel phenotypes. Generally, offspring phenotypic variation increases and shifts from the parental ecotype phenotypes, and in some cases, offspring display transgressive segregation, heterosis, or outbreeding depression. This work provides a novel contribution towards understanding mechanisms that plant implement to deal with rapid environmental changes. Specifically, plastic responses and hybridization events may interplay to maintain and increase genotypic diversity.

Após a chegada dos conquistadores europeus, as populações nativas americanas foram dizimadas por diversas razões, como guerras e doenças, o que possivelmente levou diversas linhagens genéticas autóctones à extinção. Entretanto, durante essa invasão, houve miscigenação entre os colonizadores e os povos nativos e muitos estudos genéticos têm mostrado uma importante contribuição matrilinear nativa americana na formação da população colonial. Portanto, se muitos indivíduos na atual população urbana brasileira carregam linhagens nativas americanas no seu DNA mitocondrial (mtDNA), muito da diversidade genética nativa perdida durante o período colonial pode ter se mantido, por miscigenação, nas populações urbanas. Assim, essas populações representam, efetivamente, um importante reservatório genético de linhagens nativas americanas no Brasil e em outros países americanos, constituindo o reflexo mais fiel da diversidade genética pré-colombiana em populações nativas. Baseado nisso, este estudo teve como objetivos 1) comparar os padrões de diversidade genética de linhagens nativas americanas do mtDNA em populações nativas do Sul do Brasil e da população urbana (miscigenada) adjacente; e 2) comparar, através de Computação Bayesiana Aproximada (ABC), a história demográfica de ambas populações para chegar a uma estimativa do nível de redução do tamanho efetivo populacional (Ne) das populações indígenas aqui tratadas. Foram utilizados dados já publicados da região hipervariável (HVS-I) do mtDNA de linhagens nativas de 396 indivíduos Nativos Americanos (NAT) pertencentes aos grupos Guarani, Caingangue e Charrua e de 309 indivíduos de populações miscigenadas urbanas (URB) do Sul do Brasil e do Uruguai As análises de variabilidade e estrutura genética, bem como testes de neutralidade, foram feitos no programa Arlequin 3.5 e a rede de haplótipos mitocondriais foi estimada através do método Median-Joining utilizando o programa Network 5.0. Estimativas temporais do tamanho populacional efetivo foram feitas através de Skyline Plot Bayesiano utilizando o pacote de programas do BEAST 1.8.4. Por fim, o programa DIYABC 2.1 foi utilizado para testar cenários evolutivos e para estimar o Ne dos nativos americanos pré- (Nanc) e pós-contato (Nnat), para assim, se estimar o impacto da redução de variação genética causada pela colonização europeia. Os resultados deste estudo indicam que URB é a melhor preditora da diversidade nativa ancestral, possuindo uma diversidade substancialmente maior que NAT, pelo menos na região Sul do Brasil e no Uruguai (H = 0,96 vs. 0,85, Nhap = 131 vs. 27, respectivamente). Ademais, a composição de haplogrupos é bastante diferente entre as populações, sugerindo que a população nativa tenha tido eventos de gargalo afetando os haplogrupos B2 e C1 e super-representando o haplogrupo A2. Em relação à demografia histórica, observou-se que URB mantém sinais de expansão remetendo à entrada na América, contrastando com NAT em que esses sinais estão erodidos, apenas retendo sinais de contração populacional recente. De acordo com as estimativas aqui geradas, o declínio populacional em NAT foi de cerca de 300 vezes (84 – 555). Em outras palavras, a população efetiva nativa amricana nessa região corresponderia a apenas 0,33% (0,18% – 1,19%) da população ancestral– 99,8%, corroborando os achados de outros estudos genéticos e também com os registros históricos. / After the arrival of the European conquerors, the Native American populations were decimated due to multiple reasons, such as wars and diseases, which possibly led many autochtonous genetic lineages to extinction. However, during the European invasion of the Americas, colonizers and indigenous people admixed, and many genetic studies have shown an important Native American matrilineal contribution to the formation of the Colonial population. Therefore, if many individuals in the current urban population harbor Native American lineages in their mitochondrial DNA (mtDNA), much of Native American genetic diversity that have been lost during the Colonial Era may have been mantained by admixture in urban populations. In this case, these populations effectively represent an important reservoir of Native lineages in Brazil and other American countries, constituting the most accurate portrait of pre-Columbian genetic diverstity of Native populations. Based on this, the aims of the presente study were 1) to compare the patterns of genetic diversity of Native American mtDNA lineages in Native populations from Southern Brazil and the surrounding admixed urban populations; and 2) to compare, using Approximate Bayesian Computation (ABC), the demographic history of both groups to estimate the level of reduction in the effective population size (Ne) for the indigenous groups present here. We used mtDNA hypervariable segment (HVS-I) data of indigenous origin already published from 396 Native American individuals (NAT) belonging to the Guarani, Kaingang, and Charrua groups, and 309 individuals from Southern Brazilian and Uruguayan admixed urban populations (URB) The analyzes of variability and genetic structure, as well as the neutrality tests were accomplished using Arlequin 3.5, and the mitochondrial haplotype network estimated through the Median-Joining method available in Network 5.0. Time estimates for effective population size were performed using Bayesian Skyline Plot available in the BEAST 1.8.4 package. Finally, the DIYABC 2.1 software was used to test evolutionary scenarios and to estimate the pre (Nanc) and post-contact (Nnat) Native American Ne, and estimate the impact of the colonization process on the Native American genetic variability. The results indicate that URB is the best predictor of ancestral Native diversity, having substancially greater genetic diversity than NAT, at least in the Southern Brazilian and Uruguayan regions (H = 0.96 vs. 0.85, Nhap = 11 vs. 27, respectively). Moreover, the haplogroup compositions are very distinct between these groups, suggesting that the Native population passed through bottleneck events affecting the haplogroups B2 and C1, and overrepresenting the haplogroup A2. In relation to demographic history, we observed that URB retains signals of population expansion back to the entry in the Americas. In contrast, these signals are eroded in NAT, which maintains only signals of recent population contraction. According to our estimates, the population decline in NAT was around 300x (84 – 555x). In other words, the effective Native American population in this region would correspond to only 0.33% (0.18% – 1.19%) of the ancestral population, corroborating the findings of other genetic studies and historical records.

No description available.

Air entraining admixtures are surfactants, that are commonly used in Portland cement materials, because they form and stabilize small air bubbles distributed in the binder, thereby changing the pore size distribution. The aim of these additives is to increase the durability of the cured binder, especially in climatic conditions, where it must withstand low temperatures, and simultaneously improving the workability in the plastic state. The effect of air entraining admixtures in alkali-activated slag was studied for certain properties. Air entraining admixtures were able to entrain the air in the alkali-activated matrix, they changed the pore size distribution, which resulted in a reduction in capillary pressure in the porous complex, and there was a reduction of shrinkage under autogenous conditions, respectively. The improvement of workability is certainly also positive, but on the other hand there has been a bad effect on flexural strength and compressive strength. The morphology of the air entrained binder was observed by scanning electron microscopy, and simultaneously the effect of air entrained admixtures on hydration was observed by isothermal calorimetry.

Fly ash is now much used as an admixture to concrete. This master´s thesis focuses on the use of fly ash as an active admixture in concrete environment for XF. The thesis has two parts. The first part collected theoretical information about the origin and behavior of fly ash in fresh and hardened concrete. In the second part was experimental verification of these characteristics. The purpouse of this thesis is to demonstrate that the fly ash attribute to meet all environmental XF.

The project elaborated in frame of engineering studies branch N2332-00. The project is submitting design of technology production sand mixture with cement binder – Portland binder CEM I 42,5 N. Pursuant to of the literary pursuit a problem of the sand mixture with cement binder was tested few sand mixture. As optimal composition it turned out application sand mixture with 2 % CaCl2 content and 1 – 2 % Dextrin content. Sand mixture with cement has good moulder and regenerating.

No description available.

Reconstructing the origins and evolutionary journey of humans is a central piece of biology. Complementary to archeology, population genetics studying genetic variation among individuals in extant populations has made considerable progress in understanding the evolution of our species. Particularly, studies in indigenous humans provide valuable insights on the prehistory of humans because their life history closely resembles that of our ancestors. Despite these efforts, it can be difficult to disentangle population genetic inferences because of the interplay among evolutionary forces, including mutation, recombination, selection, and demographic processes. To date, few studies have adopted a comprehensive framework to jointly account for these confounding effects. The shortage of such an approach inspired this dissertation work, which centered on the development of model-based analysis and demonstrated its importance in population genetic inferences. Indigenous African Pygmy hunter-gatherers have been long studied because of interest in their short stature, foraging subsistence strategy in rainforests, and long-term socio-economic relationship with nearby farmers. I proposed detailed demographic models using genomes from seven Western African Pygmies and nine Western African farmers (Appendix A). Statistical evidence was shown for a much deeper divergence than previously thought and for asymmetric migrations with a larger contribution from the farmers to Pygmies. The model-based analyses revealed significant adaption signals in the Pygmies for genes involved in muscle development, bone synthesis, immunity, reproduction, etc. I also showed that the proposed model-based approach is robust to the confounding effects of evolutionary forces (Appendix A). Contrary to the low-latitude African homeland of humans, the indigenous Siberians are long-term survivors inhabiting one of the coldest places on Earth. Leveraging whole exome sequencing data from two Siberian populations, I presented demographic models for these North Asian dwellers that include divergence, isolation, and gene flow (Appendix B). The best-fit models suggested a closer genetic affinity of these Siberians to East Asians than to Europeans. Using the model-based framework, seven NCBI BioSystems gene sets showed significance for polygenic selection in these Siberians. Interestingly, many of these candidate gene sets are heavily related to diet, indicating possible adaptations to special dietary requirements in these populations in cold, resource-limited environments. Finally, I moved beyond studying the history of extant humans to explore the origins of our species in Africa (Appendix C). Specifically, with statistical analyses using genomes only from extant Africans, I rejected the null model of no archaic admixture in Africa and in turn gave the first whole-genome evidence for interbreeding among human species in Africa. Using extensive simulation analyses under various archaic admixture models, the results suggest recurrent admixture between the ancestors of archaic and modern Africans, with evidence that at least one such event occurred in the last 30,000 years in Africa.

As comunidades da Costa da Lagoa (CL) e São João do Rio Vermelho (RV) estão localizadas na Ilha de Santa Catarina, Sul do Brasil, e foram colonizadas na segunda metade do século XVIII por imigrantes vindos do Arquipélago de Açores. Estudos demográficos e genéticos mostraram também a presença de componentes africanos e ameríndios. CL é considerada isolada devido à sua localização geográfica e RV está em fase de quebra de isolado pelo aumento de migração, principalmente nos últimos 20 anos. Os objetivos deste estudo foram verificar a hipótese dos diferentes graus de isolamento nas duas comunidades, estimar as proporções de mistura étnica, assim como estabelecer comparações entre elas e com portugueses, especialmente açorianos. As freqüências de oito AIMs (FY, RB, LPL, AT3, Sb19.3, APO, PV92 e CYP1A1) e dos STRs do haplótipo estendido do cromossomo Y foram então estimadas nas comunidades de CL (n=120), RV (n=163) e na amostra urbana HM (n=50) a partir de PCR e PCR-RFLP. A informação obtida a partir das mesmas foi comparada com resultados de estudos históricos, demográficos e genéticos prévios realizados nestas comunidades. As análises estatísticas empregaram programas já descritos (GENEPOP, DISPAN, GDA, ARLEQUIN, STRUCTURE, MVSP e ADMIX 2 e 3). Com relação ao cromossomo Y, concluímos que as duas comunidades ainda apresentam semelhanças considerando as análises de diferenciação gênica. Isto pode ser devido à origem comum e recente e à proximidade geográfica, o que torna possível um fluxo de homens entre as duas comunidades. Entretanto, o acréscimo no número de marcadores ligados ao cromossomo Y permitiu a diferenciação entre estas duas comunidades, como mostram os valores de FST e de diferenciação haplotípica. As estimativas de mistura indicam preponderância do componente europeu. Entretanto, dada à indisponibilidade da literatura, faz-se ainda necessária uma escolha mais adequada das freqüências parentais no caso dos Y-STRs. Admitindo que os AIMs sejam marcadores mais eficientes em estimativas de mistura étnica, dado seus altos diferenciais de freqüência alélica entre populações parentais, as contribuições de populações não européias (principalmente africanas) observadas mantém a hipótese de cruzamentos preferenciais entre homens portugueses e mulheres ameríndias e/ou africanas na formação das comunidades. / The communities of Costa da Lagoa (CL) and São João do Rio Vermelho (RV) are located on Santa Catarina Island, southern Brazil, and were settled on the second half of XVIII century by immigrants came from Azores Archipelago. Demographic and genetic studies have also been indicated the presence of African and Amerindian components. CL is considered genetically isolated due to its geographic localization and isolate breaking is occurring in RV due to the increased migration to the local, mainly in the last 20 years. The aims of the present study were to verify the hypothesis of the different degrees of isolation in the two communities, to estimate the proportions of ethnic admixture, as well as to establish comparisons between them and with Portuguese, particularly Azoreans. Allele frequencies of eigth AIMs (FY, RB, LPL, AT3, Sb19.3, APO, PV92 e CYP1A1) and of the extended Y haplotype STRs were estimated in the CL (n=120), RV (n=163) and in the urban sample HM (n=50) by means of PCR and PCR-RFLP. These data were compared with previous results from historical, demographical and genetical studies realized in these communities. Statistical analysis were carried out employing the GENEPOP, DISPAN, GDA, ARLEQUIN, STRUCTURE, MVSP and ADMIX 2 and 3 softwares. The communities showed more similarity in relation to Y chromosome on the analysis of gene differentiation, which could be due to the recent and common origin and the geographic proximity, and the interchange mainly male-mediated between them. However, the increased number of Y-linked STRs made possible the differentiation between these communities, as depicted by the FST values and the haplotypic differentiation. The ethnic admixture estimates detected a major European contribution but, due to the literature unavailability, a more suitable choice of the parental frequencies for the Y-STRs estimates is needed. Once AIMs are markers more efficient than Y-STRs on admixture estimates, due to their large allele frequency differentials between parental populations, the non-european contributions (mainly Africans) observed support the hypothesis of biased mating between Portuguese men and Amerindian and/or African women during the formation of these communities.