A importância atribuída aos biocombustíveis aumentou de forma drástica nos últimos anos, pois além de reduzir a dependência de petróleo e os gastos com energia fóssil, o uso de fontes de energia renováveis resulta também em uma diminuição significativa das emissões de gases tóxicos para a atmosfera. A biomassa de origem vegetal é uma das mais baratas e abundantes matérias-primas renováveis para o desenvolvimento sustentável e é uma fonte promissora para a produção de biocombustíveis. O bioetanol produzido a partir das frações lignocelulósicas, conhecido como etanol de segunda geração, tem um potencial de mercado promissor como biocombustível. No entanto, a tecnologia do processo ainda está em escala de demonstração. Há grande necessidade de melhorias no processo de produção a fim de reduzir o custo de produção. Caso houvesse a utilização total dos açúcares presentes na biomassa vegetal, existiria uma maior rentabilidade e competitividade, tornando esse processo mais viável. Os polissacarídeos constituintes do material lignocelulósico, como hemicelulose e celulose, por uma reação de hidrólise podem ser transformados em açúcares simples, tais como xilose e glicose, que podem ser utilizados como substrato em processos fermentativos. Algumas linhagens de leveduras não pertencentes ao gênero Saccharomyces possuem a capacidade de bioconversão das pentoses (xilose e arabinose), constituintes da fração hemicelulósica, em etanol. Neste contexto, o presente estudo objetivou isolar leveduras de madeira em fase de decomposição para avaliação das mesmas quanto à capacidade de bioconversão da xilose, principal constituinte da fração hemicelulósica, em etanol. Foram obtidas 83 colônias de leveduras do isolamento, sendo que todas foram inoculadas em meio de xilose como fonte de carbono. Somente onze isolados não apresentaram capacidade de produção de etanol a partir de xilose, os isolados que exibiram essa capacidade apresentaram uma variação de 0,60 até 6,58 g L-1 de etanol. Além dos isolados, quinze linhagens pertencentes a espécies de leveduras já conhecidas como fermentadoras de xilose foram avaliadas quanto à produção de etanol. As linhagens pertencentes às espécies Spathaspora passalidarum (HMD1.3) e Candida shehatae (HM52.2) foram as maiores produtoras de etanol e não apresentaram diferenças significativas entre elas. Dentre todos os isolados obtidos, os isolados I38 e I54 não diferiram entre si, e foram os maiores produtores de etanol. O isolado I38 apresentou resultados significativamente maiores do que as linhagens padrão Spathaspora arborariae HM19.1A e Sheffersomyces stipitis NRRLY7124, enquanto o isolado I54 não diferiu da linhagem padrão HM19.1A, mas foi superior à linhagem NRRLY7124. / The importance given to biofuels drastically increased in the last years, because besides reducing oil dependence and spending on fossil energy, the use of renewable energy sources also results in a significant reduction of toxic gas emissions to the atmosphere. Plant biomass is one of the cheapest and most abundant renewable feedstock for sustainable development and is a promising source for biofuel production. Bioethanol produced from lignocellulosic fractions, known as second generation ethanol, have a promising market potential as a biofuel. However, the process technology is still in demonstration scale. There is a great need for improvements in the production process in order to reduce the production cost. If there was a total utilization of sugars in plant biomass, there would be greater profitability and competitiveness, making this process more feasible. The polysaccharides components of lignocellulosic material, such as cellulose and hemicellulose, by hydrolysis reaction can be transformed into simple sugars such as xylose and glucose, which can be used as substrate for fermentation. Some yeast strains not belonging to the genus Saccharomyces have the ability of bioconversion of pentoses (xylose and arabinose), components of the hemicellulose fraction, to ethanol. In this context, the aim of the present study was the isolation of yeasts from decaying wood, to assess their ability in bioconversion of xylose, the main constituent of the hemicellulosic fraction, to ethanol. Eighty-three colonies were obtained from the yeasts isolation, which all were inoculated in media containing xylose as carbon source. Only eleven strains did not showed the ability of ethanol production from xylose, the strains that exhibited this ability varied between 0.60 to 6.58 g L-1 of ethanol. In addition to the isolated strains, fifteen strains belonging to yeast species already known as xylose fermenters were assessed for ethanol production. The strains belonging to the species Spathaspora passalidarum (HMD1.3) and Candida shehatae (HM52.2) were the largest producers of ethanol and showed no significant differences between them. Among all obtained strains from isolation, I38 and I54 did not differed from each other, and were the largest producers of ethanol. The I38 strain showed results significantly higher than the standard strains Spathaspora arborariae HM19.1A and Sheffersomyces stipitis NRRLY7124, while the I54 strain did not differed from the standard strain HM19.1A, but was higher than the strain NRRLY7124.

Transport sector is an essential driver of economic development and growth, and at the same time, one of the biggest contributors to climate change, responsible for almost a quarter of the global carbon dioxide emissions. The sector is 95 percent dependent on fossil fuels. International Energy Agency (IEA) scenarios present different mixes of fuels to decrease both dependence on fossil fuels and emissions, leading to a more sustainable future. The main alternative fuels proposed in the Blue map scenario, presented in the Energy Technologies Perspective 2008, were hydrogen and second-generation ethanol. An assessment of these fuels was made using the tools SLCA (Sustainability Life Cycle Assessment) and SWOT Analysis. A Framework for Strategic Sustainable Development (FSSD) is the background used to guide the assessment and to help structure the results and conclusions. The results aim to alert the transport sector stakeholders about the sustainability gaps of the scenario, so decisions can be made to lead society towards a sustainable future. / <p>Phone number 0708293568</p>

Establishing a commercial, lignocellulose-based, second-generation ethanol process has received several decades of attention by both researchers and industry. However, a fully economically viable process still remains a long-term goal. The main bottleneck to this achievement is the recalcitrance of lignocellulosic feedstocks, although there are several other factors, such as the huge investment required for second-generation ethanol facilities. An intelligent alternative solution discussed in this thesis is an integrated approach using firstgeneration ethanol plants for second-generation processes. Wheat is the major feedstock for first-generation ethanol in Europe; therefore, wheat-based lignocellulose waste, such as wheat straw, bran, and whole stillage fiber (a waste stream from first-generation wheat-based ethanol plants) was the primary focus of the integration model in this thesis. Since the major share of first-generation ethanol plant economics focuses on the animal feed DDGS (Distillers’ dried gains with solubles), the integration of lignocellulose should be designed in order to maintain DDGS quality. An ethanol-producing edible filamentous fungus, Neurospora intermedia, a potential protein source in DDGS, was considered for use as the fermenting microbe. The morphological and physiological aspects of this fungus were studied in the thesis, leading to the first report of fungal pellet development. An alternative approach of using dilute phosphoric acid to pretreat lignocellulose, as it does not negatively affect fungal growth or DDGS quality, was demonstrated in both the laboratory and on a 1m3 pilot scale. Furthermore, the process of hydrolysis of pretreated lignocelluloses and subsequent N. intermedia fermentation on lignocellulose hydrolysate was also optimized in the laboratory and scaled up to 1 m3 using an in-house pilot-scale airlift bioreactor. Fungal fermentation on acid-pretreated and enzyme-hydrolyzed wheat bran, straw and whole stillage fiber resulted in a final ethanol yield of 95%, 94% and 91% of the theoretical maximum based on the glucan content of the substrate, respectively. Integrating the first- and second-generation processes using thin stillage (a waste stream from first-generation wheat-based ethanol plants) enhanced the fungal growth on straw hydrolysate, avoiding the need for supplementing with extra nutrients. Based on the results obtained from this thesis work, a new model for integrated first- and second-generation ethanol using edible filamentous fungi processes that also adds value to animal feed (DDGS) was developed.

When discussing Asian Indian population in the U.S. their economic success and scholastic achievement dominates the discourse. Despite their perceived economic and scholastic success and their status as a “model minority”, Asian Indians experience discrimination, exclusion, and marginalization from mainstream American society. These experiences of discrimination and perceived discrimination are causing second generation Asian Indians to give up on total assimilation and re-ethnicize. They are using different pathways of re-ethnicization to re-claim and to create an ethnic identity. This thesis provides evidence, through secondary sources, that Asian Indians in the U.S. do experience discrimination or perceived discrimination, and it is historic, cultural, and systemic. This thesis also uses secondary sources to explain several pathways of re-ethnicization utilized by second generation Asian Indians who have given up on complete assimilation. The process of re-ethnicization provides second generation Asian Indians agency, positionality, and placement in American society. Asian Indians through re-ethnicization occupy and embrace the margins that separate mainstream American society and the Asian Indians community in the U.S. It allows them to act as “go –betweens”.

The focus of this paper is second-generation immigrants and their labor market performance. With increased immigration from a more diverse ethnic background during the latest decades, it has become apparent that there is a difference between immigrant ethnic groups in labor market performance, in which some groups are more disadvantaged. Now more of these children have grown up, and research shows that the difficulties their parents had, affects the second generation. It is therefore of interest to understand what causes problems and generates opportunities for the second generation and try to understand the division between groups. One theory regarding the integration over generations and the differences between groups is segmented assimilation theory, proposed by Portes and Zhous (1993). According to this theory, both individual characteristics, and the context of immigrant lives are important. Starting with this theory, this paper looks deeper into individual characteristics and context, with special attention towards the implication of the context and the labor market. The thesis does this by testing if “local context,” a concept by Ellis &amp; Almgren (2009) branched to understand the local geographical dimension at a smaller scale than national matter, in the shape of regions. The focus toward context and labor market is due to a small degree of research that attempts to explain how well the second-generation succeeds, depending on the labor market. The method for this is quantitative and builds on comparisons between regressions. A measurement called International Socioeconomic Index (ISEI) is used to explain the impact of the differences between ethnic groups. First are ordinary least square regressions with only ethnic groups, individual characteristics and no spatial aspect compared to a multilevel model based on labor market regions. Further are the spatial characteristics (whether a region is a big city or not), and the degree to which a region is knowledge-based. These factors are added in a multilevel regression to see if these spatial aspects can explain what it is about the regions that have an impact. The result shows a difference between both ethnic groups and regions, and that regions do explain some of the difference between the ethnic groups. The data also show that some non-European groups have higher status occupation than previous research has indicated. Other factors affecting immigrant groups are whether they live in a big city region or not, and how knowledge-based a region is, there it is an advantage living in regions with these factors. However, there is still an unexplained difference between ethnic groups, due to unknown factors. The result are also influenced of sample selection, it is therefore important to be aware that this result only show people with occupation and not labor market performance overall, as unemployment is not taken into account.

Árvore de componentes é uma forma hierárquica de representar imagens em níveis de cinza baseada nas relações de inclusão dos componentes conexos da imagem. A escolha da vizinhança utilizada para gerar os componentes impacta diretamente na árvore resultante, de forma que uma alteração na escolha da vizinhança pode acarretar em uma alteração na árvore de componentes obtida. Em particular, quando uma sequência de vizinhanças crescentes é usada, os nós das árvores obtidas a partir dessas vizinhanças satisfazem uma relação de inclusão, de forma que se é possível estabelecer relações entre nós de diferentes árvores. Assim sendo, o principal objetivo desta dissertação consiste no desenvolvimento de um algoritmo eficiente para a construção de uma sequência de árvores de componentes. Para tanto, será introduzida uma classe particular de sequências de vizinhanças, que não apenas satisfaz a propriedade crescente como também permite que as árvores de componentes associadas a ela sejam construídas de forma incremental. Com base nestas propriedades, um novo algoritmo de construção de árvores de componentes associado a esta classe de vizinhanças será proposto. Para analisar a eficiência do algoritmo proposto apresentamos, ao final do texto, alguns resultados práticos e teóricos obtidos com relação ao consumo de tempo e à complexidade computacional. / Component tree is a hierarchical way of representing gray-level images based on the inclusion relation of the connected components of the image. The choice of the neighborhood used to generate these components directly impacts in the resulting tree: changing the neighborhood used may cause a change in the resulting component tree. In particular, when considering a sequence of increasing neighborhoods, the nodes of the obtained from these neighborhoods will also satisfy an inclusion relation and that will make it possible to link nodes from different trees. Therefore, the main goal of this dissertation is the development of an efficient algorithm to build a sequence of component trees. In order to do that, we will introduce a class of sequences of neighborhood that not only satisfy the increasing property but also makes it possible to incrementally build the trees associated to it. This additional property will guide us to a novel algorithm, that will build the component trees associated to this class of neighborhoods. To show how efficient the proposed algorithm is, we present some experimental and theoretical results regarding time consumption and computational complexity.

Syftet med studien har varit att undersöka hur andra generationens invandrare upplever sin tillhörighet samt hur deras livsvillkor påverkas av att bo i ett stigmatiserat område. Studien har genomförts med en kvalitativ metodansats där fem semistrukturerade intervjuer har utförts. Det insamlade materialet har analyserats med hjälp av teoretiska utgångspunkter som Vanessa Mays teori om tillhörighet, Erving Goffman och Loic Waquants stigmateorier och Thomas Scheffs teori om sociala band. Resultatet visar att informanterna känner sig stigmatiserade dels för att de har utländsk bakgrund och dels för att det finns en territoriell stigmatisering genom deras bostadsområde. Informanternas föräldrar har inte alltid lyckats bli integrerade i Sverige, vilket även påverkar informanterna. Föräldrarna behöver ha en tillhörighet som då främst har blivit hemlandets kultur, som informanterna i olika grad tar efter. De flesta känner därför tillhörighet till sina föräldrars kultur och hemland, vilket också påverkar att informanterna föredrar umgänge med personer som har en liknande bakgrund. / This research addresses the understanding of how second generation immigrants perceive their sense of belonging and how their living conditions are affected by living in a stigmatized area. The study has been done with a qualitative method, where five semi-structured interviews have been conducted. The collected material has been analyzed with the help of Vanessa May’s theory of belonging, Erving Goffman and Loic Waquant’s stigma theories and Thomas Scheff’s theory of social ties. This research presents that the informants in some ways feel discriminated and stigmatized, partly because of their foreign background and partly because there is a territorial stigma through their residential area. The parents of the informants have not always managed to become integrated in Sweden, which affects the young people. As a result of this, the parents retain more of the culture of their home country, which the informants then have inherited. The majority of the informants feel that they belong to their parents culture an homeland, they then prefers to interact with people with similar background.

Introduction: More than one-third of adults and 17% of children/adolescents in the US are overweight or obese contributing to significant morbidity and mortality, and healthcare costs. Studies have reported the persistence of adolescent obesity to adulthood, resulting in increased risk of chronic diseases such as asthma, type 2 diabetes mellitus, cardiovascular, and liver diseases. Little is known about obesity patterns in subethnic populations in the US with high prevalence of obesity or overweight reported in Hispanic youth (21.9%) compared to non-Hispanic blacks (19.5%) and non-Hispanic whites (14.7%). Several genetic, uterine, and nutritional factors, and unhealthy behaviors were identified as risk factors. Evidence is emerging about the possible role of generational status in influencing adolescent obesity. The purpose of this study is to assess the association of generation status with adolescent overweight or obesity in Hispanics in the US. Methods: Data from the 2011-2012 National Survey of Children's Health (NSCH)were used to conduct this study. Only Hispanic adolescents aged 10 to 17 years were included as study population. Using the age-sex-race specific cut-off points, we defined adolescent as being overweight or obese if they were above 85th or 95th percentile cut off point values for BMI. Generation status of an adolescent was categorized into three groups: a) generation 1 for those who were not born in US or to US citizens abroad, and migrated to US as children, b) generation 2 are those born in US but have at least one parent who is foreign born, and c) generation 3 or higher adolescents are those born in US to native-born parents. Multivariable models were conducted to test the association of generation status with adolescent obesity in Hispanics, adjusting for potential confounders. Results: A total of 5,217 Hispanic adolescents were included in the study. Approximately 1,650 and 31.7% of adolescents reported being overweight or obese. Approximately 857, 2,216 and 2,144 of adolescents are 1st, 2nd and 3rd generation Hispanic youth. Comparing to 3rd generation adolescents, those belonging to 1st and 2ndgenerations were associated with increased odds of adolescent obesity in Hispanics OR1.48, 95% CI 1.177 – 1.867 and OR 1.405, 95% CI 1.227-1.610 for 1st and 2nd generation, respectively. Conclusion: Generational status is associated with increased relative odds of overweight or obesity in Hispanic adolescents. Aggregated estimates not accounting for nativity or county of origin of an adolescent contribute to significant heterogeneity or disparities in obesity prevalence or patterns, with implications for generation-specific interventions.

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La vitesse de flamme laminaire représente une grandeur physique clé à mesurer car elle permet d'obtenir des données fondamentales sur la réactivité, la diffusivité et l'exothermicité du carburant. Elle est également un des paramètres utilisés pour le développement et la validation des mécanismes réactionnels détaillés ainsi que pour la modélisation de la combustion turbulente. Bien que cette grandeur physique ait fait l'objet de nombreuses études expérimentales depuis plusieurs décennies, sa méconnaissance sur des carburants multi-composant dans des conditions haute-pression et haute-température similaires à celles existantes dans les chambres de combustion reste un sujet d'actualité pour les industriels des secteurs automobile et aéronautique. Au cours de cette thèse, un brûleur de configuration bec Bunsen fonctionnant avec un prémélange gazeux combustible/air a été conçu pour produire une flamme laminaire à pression élevée tout en permettant la mesure par voie optique de la vitesse de flamme laminaire de carburants multi-composant (kérosène, biocarburants de seconde génération...). La mesure est basée sur la détection du contour de flamme par diverses diagnostics optiques comme la chimiluminescence OH*, la PLIF-OH et la PLIF-acétone/aromatique. En premier lieu, les mélanges de carburants purs gazeux (CH4) ou liquide (acétone) avec de l'air ont été étudiés pour valider le brûleur expérimental et la méthodologie de mesure de la vitesse de flamme laminaire par voie optique. Les évolutions de la vitesse de flamme laminaire pour des carburants de type kérosène (composants purs, surrogate LUCHE et Jet A-1) en fonction de la pression, température de préchauffage et richesse ont été ensuite étudiées et comparées avec des simulations numériques utilisant un mécanisme réactionnel détaillé. La dernière partie de la thèse est consacrée à l'étude de l'influence des composés oxygénés présents dans un biocarburant de seconde génération de type d'essence sur la vitesse de flamme laminaire. Après avoir mesuré la vitesse de flamme laminaire de différentes molécules oxygénées, les effets d'addition de ces composés oxygénés dans le carburant ont été quantifiés / Laminar flame speed is one of the key parameters for understanding reactivity, diffusivity and exothermicity of fuels. It is also useful to validate both the kinetic chemical mechanisms as well as turbulent models. Although laminar flame speeds of many types of fuels have been investigated over many decades using various combustion methodologies, accurate measurements of laminar flame speeds of multicomponent liquid fuels in high-pressure and high-temperature conditions similar to the operating conditions encountered in aircraft/automobile combustion engines are still required. In this current study, a high-pressure combustion chamber was specifically developed to measure the laminar flame speed of multicomponent liquid fuels such as kerosene and second generation of biofuels. The architecture of the burner is based on a preheated premixed Bunsen flame burner operated in elevated pressure and temperature conditions. The optical diagnostics used to measure the laminar flame speed are based on the detection of the flame contour by using OH* chemiluminescence, OH- and acetone/aromatic- Planar laser induced fluorescence (PLIF). The laminar flame speed of gaseous CH4/air and acetone/air premixed laminar flames were first measured for validating the experimental setup and the measurement methodologies. Then, the laminar flame speeds of kerosene or surrogate fuels (neat kerosene compounds, LUCHE surrogate kerosene and Jet A-1) were investigated and compared with simulation results using detailed kinetic mechanisms over a large range of conditions including pressure, temperature and equivalence ratio. The last part of the thesis was devoted to study the effect of oxygenated compounds contained in the second generation of biofuels on the laminar flame speeds. After measuring the laminar flame speeds of various oxygenated components present in partially hydro-processed lignocellulosic biomass pyrolysis oils, the effect of these oxygenates on the flame speeds of these fuels were quantitatively investigated