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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

Dimensão fractal e métodos quantitativos aplicados ao estudo de comunidades do macrobentos marinhos / Fractal Dimension and quantitative methods applied to the study of marine communities

Carina Waiteman Rodrigues 19 October 2017 (has links)
A macroalga Sargassum C. Agardh é de reconhecida importância ecológica nos ecossistemas costeiros, particularmente nas comunidades de costões rochosos de regiões tropicais e temperadas quentes. Está amplamente distribuída na costa sudeste brasileira, sendo frequente em costões rochosos de locais moderados ou protegidos do embate de ondas. Nesses ambientes pode formar bancos densos e extensos, estruturalmente complexos, capaz de prover microhabitats variados para uma grande diversidade de organismos. Os bancos de Sargassum são suscetíveis a mudanças sazonais na sua biomassa e/ou estado fisiológico relacionados a fatores abióticos e bióticos, sendo que essas variações podem influenciar drasticamente a distribuição e densidade dos organismos associados às algas. A complexidade desse substrato tem sido avaliada por meio de várias medidas, sendo quantitativas, como peso, as mais utilizadas. O presente trabalho tem como objetivo avaliar o desempenho de diferentes medidas quantitativas da complexidade estrutural de bancos de Sargassum filipendula i) no desenvolvimento temporal da complexidade estrutural da alga em dois ambientes hidrodinamicamente diferentes e ii) na composição e distribuição dos organismos epifaunais. Foram coletadas 15 frondes de S. filipendula por mês, durante 13 meses, nas praias da Fortaleza e do Lamberto, Ubatuba, SP. A fauna presente nessas frondes foi obtida através de lavagem e peneiramento contínuo. O período de amostragem caracterizou-se por ser atípico, apresentando altas temperaturas ao longo de todo o ano e um verão com baixa pluviometria. Este fato influenciou fortemente a variação sazonal do S. filipendula e epífitas associadas, ocasionando elevados valores de peso seco entre a primavera e verão. Os resultados das comparações das medidas analisadas mostraram que um único parâmetro não é representativo da complexidade estrutural da alga, uma vez que cada medida apresentou diferenças em relação à abundância e diversidade da fauna. Estes dois indicadores também mostraram correlação positiva com todos os parâmetros de complexidade do substrato. Houve diferença significativa entre as praias, e as frondes do Lamberto foram estruturalmente mais complexas, suportando a maior abundância. Contudo, foram as frondes do Fortaleza que exibiram os maiores valores de riqueza de grupos. Discute-se o emprego de mais uma de uma medida quantitativa para mensurar a complexidade estrutural do habitat. / The Sargassum C. Agardh macroalgae is of recognized ecological importance in coastal ecosystems, particularly in the rocky coastal communities of tropical and warm temperate regions. It is widely distributed on the southeast coast of Brazil, being frequent in rocky shores of moderate locations or protected from the impacts of waves. In these environments can form dense and extensive banks, structurally complex, capable of providing microhabitats varied for a great diversity of organisms. The Sargassum banks are susceptible to seasonal changes in their biomass and/or physiological status related to abiotic and biotic factors, and these variations can drastically influence the distribution and density of organisms associated with algae. The complexity of this substrate has been evaluated by means of several measures, being quantitative, as dry weight, the most used. The present work aims to evaluate the performance of different quantitative measures of the structural complexity of Sargassum filipendula banks i) in the temporal development of algae structural complexity in two hydrodynamically different environments and ii) in the composition and distribution of epifaunal organisms. Fifteen fronds of S. filipendula were collected per month, during 13 months, on the beaches of Fortaleza and Lamberto, Ubatuba, SP. The fauna present in these fronds was obtained through continuous washing and sieving. The sampling period was characterized by being atypical, presenting high temperatures throughout the year and a summer with low rainfall. This fact strongly influenced the seasonal variation of S. filipendula and associated epiphytes, causing high values of dry weight between spring and summer. The results of the comparisons of the measures analyzed showed that a single parameter is not representative of the structural complexity of the algae, since each measure presented differences in relation to the abundance and diversity of the fauna. These two indicators also showed a positive correlation with all parameters of substrate complexity. There was a significant difference between the beaches, and the Lambert fronds were structurally more complex, bearing the greatest abundance. However, it was the fronds of Fortaleza that exhibited the highest values of group richness. We discuss the use of one more of a quantitative measure to measure the structural complexity of the habitat.
12

Biossorção de tório e urânio pela macroalga marinha sargassum filipendula / Biosorption of thorium and uranium by marine algal sargassum filipendula

Antonia Carolina Silva 31 March 2010 (has links)
Por ser um material de baixo custo e apresentar propriedades ligantes, a macroalga marinha Sargassum filipendula vem sendo utilizada como material biossorvente no processo de biossorção de metais. No presente trabalho a alga marrom foi utilizada no estudo cinético e de equilíbrio dos íons de tório e urânio individuais e os resultados comparados à biossorção desses metais em sistema binário. Os testes foram realizados nas concentrações 1 e 10 mg/L e pH= 1,0 e 4,0 na temperatura de 25 1C. A melhor condição para biossorção de tório foi encontrada para 1 mg/L e pH= 1,0, enquanto que para urânio foi em 1 mg/L e pH= 4,0. O estudo cinético de biossorção de tório mostrou que o modelo de segunda ordem descreve melhor os dados experimentais em 1 mg/L (R2= 0,9987) e 10 mg/L (R2= 0,9919) em pH= 1,0 e 1 mg/L (R2= 0,9976) em pH= 4,0, enquanto em 10 mg/L (R2= 0,9787) pH= 4,0 a curva encontrada representou uma cinética de primeira ordem. Para a cinética de urânio os dois modelos se adequaram bem aos dados em ambas as condições experimentais. O estudo de equilíbrio mostrou um perfil crescente de captação de tório, com uma remoção de 96% e 54% do metal em pH= 1,0 e 4,0, respectivamente, a partir da Co= 1 mg/L. A melhor eficiência de captação dos íons de urânio foi de 33% para Co= 100 mg/L em pH= 1,0 e 71% para Co= 1 mg/L em pH= 4,0. Os dados experimentais da isoterma de tório mostraram-se mais adequados ao modelo de Freundlich para pH= 1,0, enquanto que para o pH= 4,0 esses foram melhor representados pelo modelo de Langmuir, com valores de coeficiente de determinação superiores. Em relação à isoterma do urânio, o modelo de Freundlich representou bem os dados experimentais. Os parâmetros de equilíbrio calculados a partir do modelo de Langmuir (kL, qmax ) e Freundlich (kF, n) indicaram uma maior afinidade da biomassa pelos íons de tório em ambas as condições experimentais. O estudo de equilíbrio do sistema binário mostrou que a biossorção dos íons de tório não é afetada pela presença do urânio em solução. Por outro lado, a sorção do urânio foi fortemente afetada pela coexistência com os íons de tório. / Due to its low cost and ligand properties, the seaweed Sargassum filipendula is highly used as a biosorbent material for metals biosorption processes. In the present work this brown seaweed was used in the kinetic and equilibrium studies of the process of biosorption of thorium and uranium, alone and in combined solutions. Tests were performed in the range of metals concentrations from 1 to 10 mg/L and pH values 1.0 and 4.0 at 25 1C. The best condition for the biosorption of thorium was found in the low concentration of 1 mg/L at pH 1.0, while uranium was best biosorbed at the concentration of 1 mg/L at pH 4.0. The kinetic study of thorium biosorption indicated that the second-order kinetic model best represented the experimental data for the low concentration of 1 mg/L (R2= 0.9987) and 10 mg/L (R2= 0.9919) at pH 1.0; for 1.0 mg/L R2= 0.9976 at pH= 4.0, while for the most concentrated solution (10 mg/L) R2 value was equal to 09787) at pH= 4.0, following a pseudo-first order kinetics. The biosorption of uranium indicated that both kinetic models fitted the experimental data, under both experimental conditions. Equilibrium study showed an increasing thorium biosorption, for increasing initial metal concentration, reaching 96 and 54% recovery of the metal, at pH 1.0 and 4.0, respectively. The higher individual efficiencies observed were 33% biosorption for a 100 mg/L initial concentration at pH 1.0 and 71% for a 1 mg/L concentration, at pH 4.0. Experimental equilibrium data, for the element thorium, indicated a best fit on Freundlich model, at pH 1.0, while at pH 4.0 the results were best represented by the Langmuir model, due to higher determination coefficient values. Considering the uranium isotherm obtained, Freundlich model best represented experimental data, suggesting the formation of a multilayer adsorption on the surface of the biomass. Equilibrium parameters calculated from the Langmuir (kL, qmax) and Freundlich (kF, n) models, indicated a higher affinity of the biomass for thorium, in comparison to uranium in both conditions tested. The study of the binary system equilibrium showed that the biosorption of thorium was not affected by the presence of uranium in solution, due to the same uptake values observed when thorium was solely present in solution, reaching qmax= 85,95 μmol Th/g (individual) and qmax= 110,1 μmol Th/g (mixture). On the other hand, uranium biosorption was markedly affected by the presence of thorium in solution, reaching low or not significant uranium by the biomass. Key words: Biosorption, Sargassum filipendula, Thorium, Uranium.
13

Biossorção de tório e urânio pela macroalga marinha sargassum filipendula / Biosorption of thorium and uranium by marine algal sargassum filipendula

Antonia Carolina Silva 31 March 2010 (has links)
Por ser um material de baixo custo e apresentar propriedades ligantes, a macroalga marinha Sargassum filipendula vem sendo utilizada como material biossorvente no processo de biossorção de metais. No presente trabalho a alga marrom foi utilizada no estudo cinético e de equilíbrio dos íons de tório e urânio individuais e os resultados comparados à biossorção desses metais em sistema binário. Os testes foram realizados nas concentrações 1 e 10 mg/L e pH= 1,0 e 4,0 na temperatura de 25 1C. A melhor condição para biossorção de tório foi encontrada para 1 mg/L e pH= 1,0, enquanto que para urânio foi em 1 mg/L e pH= 4,0. O estudo cinético de biossorção de tório mostrou que o modelo de segunda ordem descreve melhor os dados experimentais em 1 mg/L (R2= 0,9987) e 10 mg/L (R2= 0,9919) em pH= 1,0 e 1 mg/L (R2= 0,9976) em pH= 4,0, enquanto em 10 mg/L (R2= 0,9787) pH= 4,0 a curva encontrada representou uma cinética de primeira ordem. Para a cinética de urânio os dois modelos se adequaram bem aos dados em ambas as condições experimentais. O estudo de equilíbrio mostrou um perfil crescente de captação de tório, com uma remoção de 96% e 54% do metal em pH= 1,0 e 4,0, respectivamente, a partir da Co= 1 mg/L. A melhor eficiência de captação dos íons de urânio foi de 33% para Co= 100 mg/L em pH= 1,0 e 71% para Co= 1 mg/L em pH= 4,0. Os dados experimentais da isoterma de tório mostraram-se mais adequados ao modelo de Freundlich para pH= 1,0, enquanto que para o pH= 4,0 esses foram melhor representados pelo modelo de Langmuir, com valores de coeficiente de determinação superiores. Em relação à isoterma do urânio, o modelo de Freundlich representou bem os dados experimentais. Os parâmetros de equilíbrio calculados a partir do modelo de Langmuir (kL, qmax ) e Freundlich (kF, n) indicaram uma maior afinidade da biomassa pelos íons de tório em ambas as condições experimentais. O estudo de equilíbrio do sistema binário mostrou que a biossorção dos íons de tório não é afetada pela presença do urânio em solução. Por outro lado, a sorção do urânio foi fortemente afetada pela coexistência com os íons de tório. / Due to its low cost and ligand properties, the seaweed Sargassum filipendula is highly used as a biosorbent material for metals biosorption processes. In the present work this brown seaweed was used in the kinetic and equilibrium studies of the process of biosorption of thorium and uranium, alone and in combined solutions. Tests were performed in the range of metals concentrations from 1 to 10 mg/L and pH values 1.0 and 4.0 at 25 1C. The best condition for the biosorption of thorium was found in the low concentration of 1 mg/L at pH 1.0, while uranium was best biosorbed at the concentration of 1 mg/L at pH 4.0. The kinetic study of thorium biosorption indicated that the second-order kinetic model best represented the experimental data for the low concentration of 1 mg/L (R2= 0.9987) and 10 mg/L (R2= 0.9919) at pH 1.0; for 1.0 mg/L R2= 0.9976 at pH= 4.0, while for the most concentrated solution (10 mg/L) R2 value was equal to 09787) at pH= 4.0, following a pseudo-first order kinetics. The biosorption of uranium indicated that both kinetic models fitted the experimental data, under both experimental conditions. Equilibrium study showed an increasing thorium biosorption, for increasing initial metal concentration, reaching 96 and 54% recovery of the metal, at pH 1.0 and 4.0, respectively. The higher individual efficiencies observed were 33% biosorption for a 100 mg/L initial concentration at pH 1.0 and 71% for a 1 mg/L concentration, at pH 4.0. Experimental equilibrium data, for the element thorium, indicated a best fit on Freundlich model, at pH 1.0, while at pH 4.0 the results were best represented by the Langmuir model, due to higher determination coefficient values. Considering the uranium isotherm obtained, Freundlich model best represented experimental data, suggesting the formation of a multilayer adsorption on the surface of the biomass. Equilibrium parameters calculated from the Langmuir (kL, qmax) and Freundlich (kF, n) models, indicated a higher affinity of the biomass for thorium, in comparison to uranium in both conditions tested. The study of the binary system equilibrium showed that the biosorption of thorium was not affected by the presence of uranium in solution, due to the same uptake values observed when thorium was solely present in solution, reaching qmax= 85,95 μmol Th/g (individual) and qmax= 110,1 μmol Th/g (mixture). On the other hand, uranium biosorption was markedly affected by the presence of thorium in solution, reaching low or not significant uranium by the biomass. Key words: Biosorption, Sargassum filipendula, Thorium, Uranium.
14

Trophic, Indirect, and Evolutionary Interactions in a Plant–Herbivore–Parasitoid System

Stenberg, Johan January 2008 (has links)
The aim of this thesis project was to elucidate patterns and processes associated with the biotic interactions in a natural plant–herbivore–parasitoid food web characterized by spatial and temporal heterogeneity with regard to species composition. The system examined is based on island populations of the perennial herb Meadowsweet (Filipendula ulmaria, Rosaceae), located in the Skeppsvik Archipelago. The area is subject to isostatic rebound, amounting to 0.85 cm per year; this makes it possible to calculate the age of the rising islands. Meadowsweet colonizes new islands when they are about 100 years old. Meadowsweet is consumed by two major herbivores in the study area: Galerucella tenella and Altica engstroemi (Coleoptera: Chrysomelidae). Both herbivores overwinter in the topsoil and successful colonization occurs when the islands reach a height that prevents the beetles from being removed or killed as a result of wave wash during the winter. I found that both herbivores significantly reduced individual plant fitness and population growth rate. A “cafeteria experiment” with Galerucella showed that this beetle discriminated between plants from different islands, avoiding plants from old islands which contained high concentrations of putative defence compounds, while readily accepting plants from younger islands which contained lower concentrations of these chemicals. Further, the plant species exhibited a trade-off between growth and production of the putative defence compounds. Taken together, these results were interpreted as providing evidence of herbivore-driven evolution of resistance in Meadowsweet. Further, laboratory studies suggested that Galerucella gradually includes a less preferred host plant (Rubus arcticus, Rosaceae) in its diet as Meadowsweet resistance increases. This implies that Galerucella drives its own host-breadth enlargement by selectively inducing a ‘rent rise’ in the original host, Meadowsweet. In a number of field studies I showed that the oligophagous parasitoid Asecodes mento (Hymenoptera: Eulophidae) has a strong positive effect on Meadowsweet seed set by removing large numbers of G. tenella larvae. This top-down effect is, however, altered by the presence of a close relative of G. tenella, namely G. calmariensis, which is monophagous on Purple loosestrife (Lythrum salicaria, Lythraceae). G. tenella experiences associational susceptibility when coexisting with G. calmariensis since the latter supports a higher and more fit pool of shared parasitoids and because Meadowsweet attracts a higher proportion of the shared parasitoid females than Purple loosestrife. This implies that G. tenella densities are very low in coexisting populations and that Meadowsweet experiences associational resistance and produces more seeds when co-occurring with Purple loosestrife. Thus, selection for increased resistance in Meadowsweet is likely to be relaxed in populations mixed with Purple loosestrife. I conclude that the evolution of plant resistance is likely to depend on the length of time and intensity of selection. When Meadowsweet colonizes new islands it experiences a period of enemy-free space; followed by a midlife and ageing with selection by herbivores. The intensity of this selection does, however, depend on the presence of additional plant and herbivore species.
15

Gastroduodeninės srities gleivinės oksidacinių procesų ir augalų tinktūrų poveikio eksperimentinis ir klinikinis įvertinimas / Experimental and clinical evaluation of oxidative processes and effectiveness of herbal tinctures in the gastroduodenal mucosa

Vasiliauskas, Audrius 16 June 2010 (has links)
Skrandžio ir dvylikapirštės žarnos gleivinės įvairių patologinių procesų atsiradimui (tarp jų ir opaligei) svarbią reikšmę turi organizmo pro/antioksidacinės sistemos būklė, antioksidacinės sistemos pajėgumas, lipidų peroksidacijos procesai. Šių procesų dinamikos pažinimas atskleidžia patologinio proceso grandis, suteikia galimybę panaudoti antioksidantinius preparatus šių ligų gydymui. Pastaruoju metu mokslininkų dėmesys krypsta į natūralių antioksidantų panaudojimo galimybes klinikinėje praktikoje. Darbe nustatyti gastroduodeninės gleivinės oksidacinės sistemos pakyčiai, sergant skrandžio ir dvylikapirštės žarnos opalige, ir įvertintas paprastojo kaštono (Aesculus hippocastanum (L.) bei pelkinės vingiorykštės (Filipendula ulmaria (L.) Maxim) žiedų tinktūrų poveikis gleivinės oksidacinei sistemai in vivo, sukėlus žiurkėms eksperimentinę opaligę, ir in vitro, panaudojant tyrimams eksperimentinių gyvūnų ir ligonių gleivinės biopsinę medžiagą. Remiantis eksperimentinės ir klinikinės medžiagos in vivo ir in vitro tyrimų rezultatais, parodytas šių augalų tinktūrų teigiamas, antioksidantinis poveikis, teigiamai veikiantis pažeistos gleivinės oksidacinės sistemos grandis. Gauti duomenys pagrindžia minėtų augalų tinktūrų vartojimo galimybes ligoniams, sergantiesiems gastroduodeninės srities ligomis. / Status of pro/antioxidant system, its antioxidant capacity, and processes of lipid peroxidation play an important role in various pathological processes of gastric and duodenal mucosa (including the ulcers). The knowledge about the dynamic of these processes reveals the chains of the pathological process and gives the possibility to use the antioxidant agents for the treatment of diseases. Now, the researchers tend their attention on the use of the natural antioxidants in the clinical practice. In the study, the changes of oxidative system in the gastroduodenal mucosa of patients with gastric and duodenal ulcers are estimated and the effects of tinctures from the blossoms of horse chestnut (Aesculus hippocastanum (L.)) and the flowers from meadowsweet (Filipendula ulmaria (L.) Maxim) on the mucosal oxidative system of rats with experimental ulcers in vivo and by using biopsy material in vitro are evaluated in the experimental animals and patients suffering from gastroduodenal diseases. According to data (observations in vitro and in vivo) obtained from the experimental and clinical material, antioxidant effect of biologically active substances from the tinctures positively acting on the chains of oxidative system of damaged gastroduodenal mucosa was determined. These data support the possibility to use above-mentioned plant tinctures in the patients with gastroduodenal diseases.
16

Experimental and clinical evaluation of oxidative processes and effectiveness of herbal tinctures in the gastroduodenal mucosa / Gastroduodeninės srities gleivinės oksidacinių procesų ir augalų tinktūrų poveikio eksperimentinis ir klinikinis įvertinimas

Vasiliauskas, Audrius 16 June 2010 (has links)
Skrandžio ir dvylikapirštės žarnos gleivinės įvairių patologinių procesų atsiradimui (tarp jų ir opaligei) svarbią reikšmę turi organizmo pro/antioksidacinės sistemos būklė, antioksidacinės sistemos pajėgumas, lipidų peroksidacijos procesai. Šių procesų dinamikos pažinimas atskleidžia patologinio proceso grandis, suteikia galimybę panaudoti antioksidantinius preparatus šių ligų gydymui. Status of pro/antioxidant system, its antioxidant capacity, and processes of lipid peroxidation play an important role in various pathological processes of gastric and duodenal mucosa (including the ulcers). The knowledge about the dynamic of these processes reveals the chains of the pathological process and gives the possibility to use the antioxidant agents for the treatment of diseases. Now, the researchers tend their attention on the use of the natural antioxidants in the clinical practice. In the study, the changes of oxidative system in the gastroduodenal mucosa of patients with gastric and duodenal ulcers are estimated and the effects of tinctures from the blossoms of horse chestnut (Aesculus hippocastanum (L.)) and the flowers from meadowsweet (Filipendula ulmaria (L.) Maxim) on the mucosal oxidative system of rats with experimental ulcers in vivo and by using biopsy material in vitro are evaluated in the experimental animals and patients suffering from gastroduodenal diseases. According to data (observations in vitro and in vivo) obtained from the experimental and clinical material... [to full text] / Skrandžio ir dvylikapirštės žarnos gleivinės įvairių patologinių procesų atsiradimui (tarp jų ir opaligei) svarbią reikšmę turi organizmo pro/antioksidacinės sistemos būklė, antioksidacinės sistemos pajėgumas, lipidų peroksidacijos procesai. Šių procesų dinamikos pažinimas atskleidžia patologinio proceso grandis, suteikia galimybę panaudoti antioksidantinius preparatus šių ligų gydymui. Pastaruoju metu mokslininkų dėmesys krypsta į natūralių antioksidantų panaudojimo galimybes klinikinėje praktikoje. Darbe nustatyti gastroduodeninės gleivinės oksidacinės sistemos pakyčiai, sergant skrandžio ir dvylikapirštės žarnos opalige, ir įvertintas paprastojo kaštono (Aesculus hippocastanum (L.) bei pelkinės vingiorykštės (Filipendula ulmaria (L.) Maxim) žiedų tinktūrų poveikis gleivinės oksidacinei sistemai in vivo, sukėlus žiurkėms eksperimentinę opaligę, ir in vitro, panaudojant tyrimams eksperimentinių gyvūnų ir ligonių gleivinės biopsinę medžiagą. Remiantis eksperimentinės ir klinikinės medžiagos in vivo ir in vitro tyrimų rezultatais, parodytas šių augalų tinktūrų teigiamas, antioksidantinis poveikis, teigiamai veikiantis pažeistos gleivinės oksidacinės sistemos grandis. Gauti duomenys pagrindžia minėtų augalų tinktūrų vartojimo galimybes ligoniams, sergantiesiems gastroduodeninės srities ligomis.

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