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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Influ?ncia do estresse nutricional programado na composi??o da microalga isochrysis galbana

Chagas, Bruna Maria Emerenciano das 21 December 2010 (has links)
Made available in DSpace on 2014-12-17T15:01:24Z (GMT). No. of bitstreams: 1 BrunaMEC_DISSERT.pdf: 1873830 bytes, checksum: 826b39ab376c52af03d9abc3c0b121dd (MD5) Previous issue date: 2010-12-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Global warming due to Greenhouse Gases (GHG) emissions, especially CO2, has been identified as one of the major problems of the twenty-first century, considering the consequences that could represent to planet. Currently, biological processes have been mentioned as a possible solution, especially CO2 biofixation due to association microalgae growth. This strategy has been emphasized as in addition to CO2 mitigation, occurs the production of biomass rich in compounds of high added value. The Microalgae show high photosynthetic capacity and growth rate higher than the superior plants, doubling its biomass in one day. Its culture does not show seasons, they grow in salt water and do not require irrigation, herbicides or pesticides. The lipid content of these microorganisms, depending on the species, may range from 10 to 70% of its dry weight, reaching 90% under certain culture conditions. Studies indicate that the most effective method to promote increased production of lipids in microalgae is to induce stress by limiting nitrogen content in the culture medium. These evidences justify research continuing the production of biofuels from microalgae. In this paper, it was studied the strategy of increasing the production of lipids in microalgae I. galbana with programmed nutritional stress, due to nitrogen limitation. The physiological responses of microalgae, grown in f / 2 with different concentrations of nitrogen (N: P 15,0-control, N: 5,0 P and N: P 2,5) were monitored. During exponential phase, results showed invariability in the studied conditions. However the cultures subjected to stress in stationary phase, showed lower biomass yields. There was an increase of 32,5% in carbohydrate content and 87.68% in lipids content at N: P ratio of 5,0 and an average decrease of 65% in protein content at N: P ratios of 5, 0 and 2.5. There were no significant variations in ash content, independently of cultivation and growth phase. Despite the limitation of biomass production in cultures with N: P smaller ratios, the increase of lipid accumulation highest lipids yields were observed as compared to the control culture. Given the increased concentration of lipids associated to stress, this study suggests the use of microalgae Isochrysis galbana as an alternative raw material for biofuel production / O aquecimento global decorrente da emiss?o dos gases geradores do Efeito Estufa (GEE), em especial o CO2, ? um dos problemas mais graves do s?culo XXI, tendo em vista as conseq??ncias que esse agravante pode trazer ao planeta. Atualmente, os processos biol?gicos v?m sendo apontados como uma poss?vel solu??o, principalmente a biofixa??o do CO2 por microalgas. Essa estrat?gia tem sido ressaltada, uma vez que, paralelamente a mitiga??o do CO2 ocorre ? produ??o de biomassa rica em compostos de alto valor econ?mico agregado. As microalgas possuem alta capacidade fotossint?tica e taxa de crescimento superior aos vegetais superiores, duplicam a sua biomassa em um dia. O seu cultivo n?o segue regime de safras, s?o cultivadas em meio salino simples e n?o exigem irriga??o, herbicidas ou pesticidas. O teor de lip?dios destes microrganismos, dependendo da esp?cie, varia de 1 a 70% do seu peso seco, podendo chegar a 90% em certas condi??es de cultivo. Estudos indicam que ? poss?vel aumentar a produ??o de lip?dios pelas microalgas atrav?s de estresses fisiol?gicos induzidos pela restri??o do nitrog?nio no meio de cultura. Essas evid?ncias justificam pesquisas envolvendo a produ??o de biocombust?veis a partir de microalgas. No presente trabalho, estudou-se a estrat?gia de aumentar a produ??o de lip?dios pela microalga I. galbana atrav?s de um estresse nutricional programado, ocasionado pela restrin??o do nitrog?nio. Foram acompanhadas as respostas fisiol?gicas desta esp?cie, cultivada em meio f/2 com diferentes concentra??es de nitrog?nio (raz?es m?ssica N:P 15,0-controle, N:P 5,0 e N:P 2,5). Durante a fase exponencial, as an?lises mostraram uma invariabilidade para os cultivos estudados. Por?m, na fase estacion?ria, os cultivos submetidos ao estresse, indicaram menores rendimentos em biomassa. Observou-se um amento de 32,5% nos n?veis de carboidratos e de 87,68% no teor de lip?deos na raz?o N:P 5,0 e uma redu??o m?dia de 65% de prote?na nas raz?es N:P 5,0 ou 2,5. N?o houve varia??es significativas no teor de cinzas, independente das condi??es de cultivo e fase de crescimento. Apesar da limita??o de biomassa, o aumento do ac?mulo de lip?dios pelas culturas estressadas, proporcionou maiores produtividades de lip?dios, conseq?entemente este estudo sugere a utiliza??o da microalga Isochrysis galbana como fonte alternativa para a produ??o de biocombust?vel
12

An isotopic and historical study of diet and migration during the great Irish Potato famine (1845-1852). High-resolution carbon and nitrogen isotope profiling of teeth to investigate migration and short-term dietary change at the Union workhouse, Kilkenny and Lukin street, London.

Beaumont, Julia January 2013 (has links)
Historical evidence from contemporary documents established that Irish migrants to London during the Great Irish Famine (1845-1852) were likely to come from low socio-economic groups in south-west Ireland, and has characterised mid-19th-century health status and living conditions in both locations. Using samples from 119 individuals from the Catholic cemetery at Lukin Street, London (1843-1854) and 20 from the Union Workhouse Famine cemetery, Kilkenny, Ireland (1847-51), mean bone collagen isotope values were established for the well-documented Irish pre-Famine potato-based diet (¿15N 10.6¿, ¿13C -19.1¿), and the diet of contemporaneous Londoners (¿15N 12.6¿, ¿13C -19.1¿). The introduction of maize as a short-term Famine relief food was identified in three Kilkenny juveniles with bone collagen ¿13C above -17¿, and incremental dentine collagen demonstrating temporal changes in ¿13C consistent with dietary change from C3 to C4 plants. Bone collagen values for two Lukin Street individuals were consistent with high marine protein consumption. Techniques developed in this study to sample increments of dentine representing nine months or less of life have improved temporal resolution not only for migration events but also short-term dietary changes and physiological status during childhood. Combining epigraphic, osteological and archaeological evidence, individual ¿lifeways¿ have been constructed using isotope data and provide insights into the connection between health, diet and skeletal manifestations of deprivation during childhood and adolescence. New models are investigated for examining maternal and infant health using dentine collagen increments formed in utero and combining dentine and bone collagen values to explore the effects of nutritional stress on bone turnover. / Arts and Humanities Council. The British Federation of Women Graduates (the Eila Campbell scholarship). The British Association for Biological, Anthropology and Osteoarchaeology (the Jane Moore prize).
13

Efeito do potássio e do sódio no crescimento e nas propriedades do lenho de árvores de Eucalyptus grandis sob duas condições de regime hídrico / Effects of potassium and sodium on growth and wood properties of Eucalyptus grandis trees under two water regime conditions

Legoas, Roger Chambi 09 December 2015 (has links)
No contexto das mudanças climáticas, a sobrevivência e a produtividade das plantações de eucaliptos poderão ser afetadas. Assim, são necessárias pesquisas em nutrição florestal, como a avaliação do K e do Na e sua interação com a disponibilidade hídrica com o crescimento e propriedades do lenho de eucaliptos. Em experimento instalado, em 20 de junho de 2010 de tipo \"Split-plot\", foram avaliadas as árvores de Eucalyptus grandis submetidas a dois regimes hídricos (100% e 63%) e três tipos de fertilização (K, Na e controle). O diâmetro do tronco (cada 15 dias, com dendrômetros) e a altura total (cada 6 meses) das árvores foram mensurados no período do 40º ao 61º mês. A umidade do solo foi analisada semanalmente e a precipitação e temperatura diariamente. Foram analisadas as propriedades do lenho de 48 árvores, no 47º mês, por amostragem destrutiva, avaliando-se a sua densidade aparente, densidade básica, estrutura anatômica e proporção cerne/alburno. Os resultados mostraram que a precipitação influenciou significativamente o crescimento das árvores, seguindo-se a temperatura mínima e a umidade do solo. O K e o Na mostraram interação com a precipitação, (i) no período seco, com a redução do incremento do tronco das árvores com o Na e a sua paralisação com o K, (ii) no período chuvoso, com o aumento do incremento em diâmetro e altura do tronco, em relação ao controle. O Na em relação ao K resultou em menor crescimento das árvores de eucalipto. Com a exclusão de 37% da chuva houve efeito negativo nas árvores com K; no tratamento controle e com aplicação de Na a exclusão não mostrou efeito significativo até o 58º mês. Em relação à (i) densidade do lenho das árvores- ocorreu a sua diminuição com K e Na (menor com Na), e incremento com a menor disponibilidade hídrica; K não diminuiu a densidade sob maior disponibilidade hídrica; (ii) anatomia do lenho- observaram-se vasos de maior diâmetro e menor frequência com K e Na (maior com K); as fibras apresentaram variação significativa com Na (com fibras mais longas e largas com menor espessura da parede); a menor disponibilidade hídrica resultante da exclusão de 37% da chuva não afetou aos vasos e fibras; (iii) relação cerne/alburno- o K e Na promoveram a formação de maior proporção de cerne em relação às árvores do tratamento controle, sem influência significativa da exclusão parcial de chuva. Relações entre anatomia e densidade do lenho mostraram que mudanças nas dimensões das fibras foram acompanhadas de mudanças na densidade do lenho; e maior taxa de crescimento nem sempre se relaciona com a diminuição da densidade do lenho. Os resultados indicaram que a perda de características desejáveis na densidade, fibras e proporção de alburno, com a adição de K ou Na (principalmente Na) na adubação básica, são altamente compensados pela maior produção de lenho, no entanto em regiões mais áridas e com maior risco de seca prolongada, potássio e sódio podem agravar o déficit hídrico. / In the context of climate change, survival and productivity of eucalyptus plantations may be affected. Thus, research is needed on nutrition and forest ecophysiology, such as the evaluation of K and Na and their interaction with water availability on the growth and wood properties of eucalyptus. In a split-plot type, experiment installed on June 20, 2010 we evaluated Eucalyptus grandis trees submitted to two water regimes (100% and 63%) and three fertilizer supplies (K, Na and control). The stem diameter was measured every 15 days with dendrometers and total height, every 6 months in the period from 40th to 61st month. Soil moisture was analyzed weekly and precipitation and temperature daily. The wood properties of 48 trees were analyzed after 47 months, by destructive sampling, evaluating their apparent density, specific gravity, anatomical structure and heartwood/sapwood proportion. The results showed that precipitation significantly influenced the growth of the trees, followed by the minimum temperature and soil moisture. K and Na showed interaction with precipitation, (i) in the dry season, by reducing the growth of the tree trunks with Na and its stoppage with K, (ii) during the rainy season, with increasing growth in diameter and height of the trunk, compared with the control. The Na, as compared to K, resulted in lower growth of the eucalyptus trees. With the artificial exclusion of 37% of throughfall there was a negative effect on the growth of trees fertilized with K; but in the control and Na treatment the rainfall exclusion showed no significant effect until 58º month. In relation to (i) density of the wood of trees, there was a decrease in K and Na (lower with Na), and an increase with lower water availability; although the K did not reduce the density under higher water availability; (ii) wood anatomy- larger vessels with lower frequency were formed with K and Na supply (with higher K); the fibers showed significant variations with Na (longer and wider fibers with smaller wall thickness); and the lower water availability from the of 37% rainfall exclusion did not affect vessels and fibers; (iii) Heartwood/sapwood ratio; K and Na promoted the formation of larger proportion of heartwood in relation to the trees from the control treatment, and there was no significant influence of the partial rainfall exclusion. Relationships between anatomy and wood density showed that changes in fiber dimensions were accompanied by changes in the wood density; and the higher growth rate is not always associated with decreased wood density. The results indicate that the loss of desirable characteristics in density, fiber and proportion of sapwood, with the addition of K or Na (mainly Na) in the basic fertilization are highly compensated by the increased wood production, though in more arid regions with increased risk of prolonged drought, potassium and sodium can aggravate water deficit.
14

An isotopic and historical study of diet and migration during the great Irish Potato Famine (1845-1852) : high-resolution carbon and nitrogen isotope profiling of teeth to investigate migration and short-term dietary change at the Union workhouse, Kilkenny and Lukin street, London

Beaumont, Julia January 2013 (has links)
Historical evidence from contemporary documents established that Irish migrants to London during the Great Irish Famine (1845-1852) were likely to come from low socio-economic groups in south-west Ireland, and has characterised mid-19th-century health status and living conditions in both locations. Using samples from 119 individuals from the Catholic cemetery at Lukin Street, London (1843-1854) and 20 from the Union Workhouse Famine cemetery, Kilkenny, Ireland (1847-51), mean bone collagen isotope values were established for the well-documented Irish pre-Famine potato-based diet (δ¹⁵N 10.6‰, δ¹³C -19.1‰), and the diet of contemporaneous Londoners (δ¹⁵N 12.6‰, δ¹³C -19.1‰). The introduction of maize as a short-term Famine relief food was identified in three Kilkenny juveniles with bone collagen δ¹³C above -17‰, and incremental dentine collagen demonstrating temporal changes in δ¹³C consistent with dietary change from C3 to C4 plants. Bone collagen values for two Lukin Street individuals were consistent with high marine protein consumption. Techniques developed in this study to sample increments of dentine representing nine months or less of life have improved temporal resolution not only for migration events but also short-term dietary changes and physiological status during childhood. Combining epigraphic, osteological and archaeological evidence, individual 'lifeways' have been constructed using isotope data and provide insights into the connection between health, diet and skeletal manifestations of deprivation during childhood and adolescence. New models are investigated for examining maternal and infant health using dentine collagen increments formed in utero and combining dentine and bone collagen values to explore the effects of nutritional stress on bone turnover.
15

Efeito do potássio e do sódio no crescimento e nas propriedades do lenho de árvores de Eucalyptus grandis sob duas condições de regime hídrico / Effects of potassium and sodium on growth and wood properties of Eucalyptus grandis trees under two water regime conditions

Roger Chambi Legoas 09 December 2015 (has links)
No contexto das mudanças climáticas, a sobrevivência e a produtividade das plantações de eucaliptos poderão ser afetadas. Assim, são necessárias pesquisas em nutrição florestal, como a avaliação do K e do Na e sua interação com a disponibilidade hídrica com o crescimento e propriedades do lenho de eucaliptos. Em experimento instalado, em 20 de junho de 2010 de tipo \"Split-plot\", foram avaliadas as árvores de Eucalyptus grandis submetidas a dois regimes hídricos (100% e 63%) e três tipos de fertilização (K, Na e controle). O diâmetro do tronco (cada 15 dias, com dendrômetros) e a altura total (cada 6 meses) das árvores foram mensurados no período do 40º ao 61º mês. A umidade do solo foi analisada semanalmente e a precipitação e temperatura diariamente. Foram analisadas as propriedades do lenho de 48 árvores, no 47º mês, por amostragem destrutiva, avaliando-se a sua densidade aparente, densidade básica, estrutura anatômica e proporção cerne/alburno. Os resultados mostraram que a precipitação influenciou significativamente o crescimento das árvores, seguindo-se a temperatura mínima e a umidade do solo. O K e o Na mostraram interação com a precipitação, (i) no período seco, com a redução do incremento do tronco das árvores com o Na e a sua paralisação com o K, (ii) no período chuvoso, com o aumento do incremento em diâmetro e altura do tronco, em relação ao controle. O Na em relação ao K resultou em menor crescimento das árvores de eucalipto. Com a exclusão de 37% da chuva houve efeito negativo nas árvores com K; no tratamento controle e com aplicação de Na a exclusão não mostrou efeito significativo até o 58º mês. Em relação à (i) densidade do lenho das árvores- ocorreu a sua diminuição com K e Na (menor com Na), e incremento com a menor disponibilidade hídrica; K não diminuiu a densidade sob maior disponibilidade hídrica; (ii) anatomia do lenho- observaram-se vasos de maior diâmetro e menor frequência com K e Na (maior com K); as fibras apresentaram variação significativa com Na (com fibras mais longas e largas com menor espessura da parede); a menor disponibilidade hídrica resultante da exclusão de 37% da chuva não afetou aos vasos e fibras; (iii) relação cerne/alburno- o K e Na promoveram a formação de maior proporção de cerne em relação às árvores do tratamento controle, sem influência significativa da exclusão parcial de chuva. Relações entre anatomia e densidade do lenho mostraram que mudanças nas dimensões das fibras foram acompanhadas de mudanças na densidade do lenho; e maior taxa de crescimento nem sempre se relaciona com a diminuição da densidade do lenho. Os resultados indicaram que a perda de características desejáveis na densidade, fibras e proporção de alburno, com a adição de K ou Na (principalmente Na) na adubação básica, são altamente compensados pela maior produção de lenho, no entanto em regiões mais áridas e com maior risco de seca prolongada, potássio e sódio podem agravar o déficit hídrico. / In the context of climate change, survival and productivity of eucalyptus plantations may be affected. Thus, research is needed on nutrition and forest ecophysiology, such as the evaluation of K and Na and their interaction with water availability on the growth and wood properties of eucalyptus. In a split-plot type, experiment installed on June 20, 2010 we evaluated Eucalyptus grandis trees submitted to two water regimes (100% and 63%) and three fertilizer supplies (K, Na and control). The stem diameter was measured every 15 days with dendrometers and total height, every 6 months in the period from 40th to 61st month. Soil moisture was analyzed weekly and precipitation and temperature daily. The wood properties of 48 trees were analyzed after 47 months, by destructive sampling, evaluating their apparent density, specific gravity, anatomical structure and heartwood/sapwood proportion. The results showed that precipitation significantly influenced the growth of the trees, followed by the minimum temperature and soil moisture. K and Na showed interaction with precipitation, (i) in the dry season, by reducing the growth of the tree trunks with Na and its stoppage with K, (ii) during the rainy season, with increasing growth in diameter and height of the trunk, compared with the control. The Na, as compared to K, resulted in lower growth of the eucalyptus trees. With the artificial exclusion of 37% of throughfall there was a negative effect on the growth of trees fertilized with K; but in the control and Na treatment the rainfall exclusion showed no significant effect until 58º month. In relation to (i) density of the wood of trees, there was a decrease in K and Na (lower with Na), and an increase with lower water availability; although the K did not reduce the density under higher water availability; (ii) wood anatomy- larger vessels with lower frequency were formed with K and Na supply (with higher K); the fibers showed significant variations with Na (longer and wider fibers with smaller wall thickness); and the lower water availability from the of 37% rainfall exclusion did not affect vessels and fibers; (iii) Heartwood/sapwood ratio; K and Na promoted the formation of larger proportion of heartwood in relation to the trees from the control treatment, and there was no significant influence of the partial rainfall exclusion. Relationships between anatomy and wood density showed that changes in fiber dimensions were accompanied by changes in the wood density; and the higher growth rate is not always associated with decreased wood density. The results indicate that the loss of desirable characteristics in density, fiber and proportion of sapwood, with the addition of K or Na (mainly Na) in the basic fertilization are highly compensated by the increased wood production, though in more arid regions with increased risk of prolonged drought, potassium and sodium can aggravate water deficit.
16

Etude des facteurs de risque et de pathogénicité et de l’évolution spatio-temporelle de la maladie de l’œdème chez le sanglier (Sus scrofa) en Ardèche / Study of risk and pathogenicity factors and spatio-temporal evolution of oedema disease in wild boar (Sus scrofa) in Ardeche

Petit, Geoffrey 03 October 2019 (has links)
La maladie de l’œdème est une maladie connue depuis de nombreuses années chez le porc. Les premiers cas recensés dans une population de suidés sauvages sont apparus en 2013 en Ardèche. Un nouveau foyer de cette maladie est ensuite apparu en 2016 dans les Pyrénées-Orientales à la frontière entre la France et l’Espagne. Comprendre les facteurs permettant son apparition ainsi que sa transmission est nécessaire afin d’anticiper de futures mortalités dues à cette maladie. Dans cette thèse, une analyse épidémiologique de cette maladie chez le sanglier a été réalisée. Des clusters de mortalités sont alors apparus et ont permis de mettre en évidence une possible source de contamination unique et récurrente dans le temps. La mise en place d’une nouvelle méthode pour étudier la détectabilité des cadavres de sanglier a souligné la difficulté de retrouver des cadavres de sanglier en forêt. La dernière analyse épidémiologique à partir d’un modèle de type « Spatial point pattern » a mis en avant de possibles facteurs de risque d’apparition et de transmission qui ont ensuite été analysés plus précisément. L’analyse des données issus des tableaux de chasse en Ardèche a été réalisée afin de détecter des variations de la densité et du ratio J/A des populations de sanglier suggérant un stress alimentaire chez le sanglier, un prodrome ou une conséquence de la maladie. Aucun stress alimentaire ne fut détecté lors de cette analyse. Des hypothèses ont pu être émises pour expliquer certaines variations observées : i) la conséquence directe de la maladie, ii) un phénomène environnemental particulier et iii) un évènement pathogénique. La piste de l’événement pathogénique a été approfondie avec la découverte du SDRP (syndrome dysgénésique et respiratoire du porc). Les interactions porcs-sangliers, nombreuses en Ardèche, ont été déterminées comme potentiellement responsables du passage de la bactérie entre le compartiment domestique et sauvage. Une étude génétique a également été effectuée pour investiguer le gène alpha-1-fucosyltransferase associé à la sensibilité du porc à la maladie. Tous les sangliers analysés étaient sensibles à la maladie. D’autres analyses complémentaires sont nécessaires afin de comprendre au mieux cette maladie ainsi que les différents facteurs de risque pour l’apparition mais également la transmission. / Edema disease has been a known disease in pigs for many years. The first cases recorded in a population of wild suids appeared in 2013 in Ardèche. A new outbreak of this disease then emerged in 2016 in the Pyrénées-Orientales on the border between France and Spain. Understanding the factors that enable its onset and transmission is necessary to anticipate future mortality from this disease. In this thesis, an epidemiological analysis of this disease in wild boar was carried out. Clusters of mortalities then emerged, highlighting a possible single and recurrent source of contamination over time. The introduction of a new method to study the detectability of wild boar corpses highlighted the difficulty of finding wild boar corpses in the forest. The latest epidemiological analysis using a Spatial point pattern model highlighted possible risk factors for onset and transmission, which were then analysed more precisely. Analysis of data from hunting tables in the Ardèche was carried out in order to detect variations in the density and J/A ratio of wild boar populations suggesting food stress in the wild boar, a prodrome or consequence of the disease. No dietary stress was detected during this analysis. Assumptions could be made to explain some observed variations: i) the direct consequence of the disease, ii) a particular environmental phenomenon and iii) a pathogenic event. The trail of the pathogenic event was deepened with the discovery of the PRRS (Pork Respiratory and Dygesic Syndrome). The pig-boar interactions, numerous in the Ardeche, were determined as potentially responsible for the passage of the bacteria between the domestic and wild compartment. A genetic study was also conducted to investigate the alpha-1-fucosyltransferase gene associated with the susceptibility of pigs to the disease. All the wild boars tested were susceptible to the disease.Further further analysis is needed in order to better understand this disease as well as the different risk factors for both onset and transmission.

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