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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.
151

Studien zur Synthese von cofacialen Chlorindimeren zur Untersuchung des Symmetrie-Einflusses auf den lichtinduzierten Elektronentransfer

Hanke, Daniela. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2004--Bremen.
152

Temporal Variability of Satellite-Derived Chlorophyll and Sea Suface Temperature in the California Current

Legaard, Kasey January 2004 (has links) (PDF)
No description available.
153

EVALUATION OF ALGAE CONCENTRATION IN MANURE BASED MEDIA

Pecegueiro do Amaral, Maira Freire 01 January 2012 (has links)
Algae can be used to treat wastewater and manure while producing a feedstock for renewable energy. Algae require nutrients to achieve their maximum growth and manure could provide those nutrients, thereby reducing the cost of algae production and the impact of manure treatment. Algae concentration during cultivation is a critical variable that is difficult to measure due to the high concentration of suspended solids present in manure. This dissertation addresses methods to measure algae concentration in the presence of manure solids. Quantifying the algae concentration gravimetrically or by optical density was unreliable due to manure solids interfering with the measurement. Cell counting to determine algae concentration was accurate but time consuming, subjective, required dilution of concentrated samples and only small sample volumes could be measured. Chlorophyll extraction was a consistent method to determine algae concentration in manure based media, but the model had to be adjusted to account for solids interference. The proposed equation predicted chlorophyll concentration from Chlorella vulgaris in dairy manure better than the reference equation. Different algae strains (Chlorella vulgaris, Cylindrocystis sp, and Scenedesmus sp.) and manure sources (dairy, beef, swine, and sheep) were used to validate the proposed equation and all combinations had a linear relationship between actual and predicted chlorophyll concentration, but not all comparisons followed a 1:1 reference line. Even with chlorophyll extraction the manure solids interfered with the chlorophyll measurement and calibrations had to be developed based on manure type. A method based on spectral deconvolution was used to quantify algae concentration in the presence of manure without chlorophyll extraction. Various manure-algae mixtures were scanned with a spectrophotometer. Algae concentration was accurately determined with the four manure sources. Measuring algae concentration required absorbance spectra from 600 to 700 nm and manure solids concentration between 280 and 350 nm. Spectral deconvolution was able to differentiate algae concentration and manure solids concentration with a Pearson coefficient of 95.3% and 99.8% respectively. This method proved to be an accurate and efficient method for estimating algae and manure solids content in unprocessed samples. A critical factor was utilizing appropriate reference spectra.
154

Recuperação das trocas gasosas e fluorescência da clorofila em plantas de Annona emarginata (Schltdl.) H. Rainer submetidas a estrese hídrico

Mantoan, Luís Paulo Benetti [UNESP] 22 November 2013 (has links) (PDF)
Made available in DSpace on 2014-08-13T14:50:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-11-22Bitstream added on 2014-08-13T18:00:45Z : No. of bitstreams: 1 000754696_20141122.pdf: 234844 bytes, checksum: 8e702d577f331bcdedad80437ac6ecfd (MD5) / O presente estudo objetivou avaliar a capacidade de recuperação de Annona emarginata (Schltdl.) H. Rainer após estresse hídrico em função das variações das trocas gasosas, fluorescência da clorofila a e atividade de enzimas antioxidantes. O experimento foi implantado em blocos casualizados com três tratamentos (Irrigação, Suspensão de Irrigação e Reidratação) e quatro repetições de seis plantas por parcela totalizando 24 plantas. Foram avaliadas as seguintes variáveis: conteúdo relativo de água das folhas (CRA), trocas gasosas (assimilação de CO2, A; condutância estomática, GS; transpiração, E; concentração de carbono interno, Ci; eficiência de uso da água, A/E e eficiência de carboxilação, A/Ci), fluorescência da clorofila a (rendimento quântico máximo, FV/FM; fluorescência máxima da folha sob escuro, FM e fluorescência mínima da folha sob escuro, Fo), enzimas antioxidantes (superóxido dismutase, SOD, EC. 1.15.1.1 e peroxidase, POD, EC. 1.11.1.7) e peroxidação de lipídeos. Os dados foram submetidos a analise de variância e as médias comparadas pelo teste Tukey a 5% de probabilidade e/ou desvio padrão. Aos 38 Dias Após o Inicio dos Tratamentos (DAIT) (dia da reidratação), o CRA nas plantas irrigadas apresentou 87% reduzindo para 73% nas plantas sob suspensão de irrigação onde foi verificado assimilação de CO2 nula. Embora o CRA das plantas reidratadas tenha se recuperado ao nível das plantas no inicio dos tratamentos, as trocas gasosas apresentaram recuperação parcial. A atividade das enzimas SOD e POD tanto de folhas como de raízes apresentou recuperação após a reidratação e não foram observadas alterações no nível de peroxidação de lipídeos de folhas e raízes nos três tratamentos. Nas analises de fluorescência da clorofila a não foram detectados danos ao fotossistema II e nem alterações na eficiência do aparato fotoquímico tanto das plantas sob suspensão ... / The present study aimed to evaluate the recoverability of Annona emarginata (Schltdl.) H. Rainer after water stress through changes in the gas exchange, chlorophyll a fluorescence and antioxidant enzymes activity. The experiment was implanted in a randomized block design with three treatments (Irrigation, Suspension of Irrigation and Rehydration) and four replicates of six plants per plot totaling 24 plants. The following variables were evaluated: relative water content of leaves (RWC), gas exchange (CO2 assimilation, A; stomatal conductance, GS; transpiration, E; internal carbon concentration, Ci; water use efficiency, A/E and carboxylation efficiency, A/Ci), chlorophyll a fluorescence (maximum quantum yield, FV/FM; maximal leaf fluorescence under dark, FM; minimum leaf fluorescence under dark, Fo), antioxidant enzymes (superoxide dismutase, SOD, EC. 1.15.1.1 and peroxidase, POD, EC. 1.11.1.7) and lipid peroxidation. The data were submitted to analysis of variance and means were compared by Tukey test at 5% probability and/or standard deviation. At 38 Day After Treatments Beginning (DATB) (day of rehydration), the RWC in irrigated plants showed 87% reducing to 73% in plants under suspension of irrigation where has been verified null CO2 assimilation. Although the RWC of rehydrated plants has recovered to the level of the plants in the beginning of treatments, gas exchange showed partial recovery. The activity of SOD and POD of both leaves and roots showed recovery after rehydration and no changes were observed in the level of lipid peroxidation in leaves and roots in the three treatments. In the analysis of chlorophyll a fluorescence were not detected damage in the photosystem II and neither changes in the efficiency of the photochemical apparatus in both plants under suspension of irrigation and rehydrated in relation to irrigated. Therefore, even with the recovery of the activity of SOD and POD ...
155

Variabilidade espacial e temporal das concentrações de clorofila na Baía de Guanabara (RJ) utilizando imagens MERIS e dados in situ / Spacial and temporal variability of the chlorophyll concentration in Guanabara Bay (RJ), using MERIS images and in situ data

Renata De Michielli Grassi 18 August 2014 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este trabalho teve como objetivo principal implementar um algoritmo empírico para o monitoramento do processo de eutrofização da Baía de Guanabara (BG), Rio de Janeiro (RJ), utilizando dados de clorofila-a coletados in situ e imagens de satélite coletadas pelo sensor MERIS, a bordo do satélite ENVISAT, da Agência Espacial Européia (ESA). Para a elaboração do algoritmo foi utilizada uma série histórica de clorofila-a (Out/2002 a Jan/2012) fornecida pelo Laboratório de Biologia Marinha da UFRJ, que, acoplada aos dados radiométricos coletados pelo sensor MERIS em datas concomitantes com as coletas in situ de clorofila-a, permitiu a determinação das curvas de regressão que deram origem aos algorítmos. Diversas combinações de bandas foram utilizadas, com ênfase nos comprimentos de onda do verde, vermelho e infra-vermelho próximo. O algoritmo escolhido (R = 0,66 e MRE = 77,5%) fez uso dos comprimentos de onda entre o verde e o vermelho (665, 680, 560 e 620 nm) e apresentou resultado satisfatório, apesar das limitações devido à complexidade da área de estudo e problemas no algoritmo de correção atmosférica . Algorítmos típicos de água do Caso I (OC3 e OC4) também foram testados, assim como os algoritmos FLH e MCI, aconselhados para águas com concentrações elevadas de Chl-a, todos com resultados insatisfatório. Como observado por estudos pretéritos, a Baia de Guanabara possui alta variabilidade espacial e temporal de concentrações de clorofila-a, com as maiores concentrações no período úmido (meses: 01, 02, 03, 10, 11 12) e nas porções marginais (~ 100 mg.m-3), particularmente na borda Oeste da baia, e menores concentrações no período seco e no canal principal de circulação (~ 20 mg.m-3). O presente trabalho é pioneiro na construção e aplicação de algoritmos bio-óptico para a região da BG utilizando imagens MERIS. Apesar dos bons resultados, o presente algorítmo não deve ser considerado definitivo, e recomenda-se para trabalhos futuros testar os diferentes modelos de correção atmosférico para as imagens MERIS. / This work aimed to implement an empirical algorithm for monitoring the process of eutrophication at Guanabara Bay (BG), Rio de Janeiro (RJ), using in situ chlorophyll-a data and satellite images by MERIS sensor, onboard ENVISAT satellite, from European Space Agency (ESA). A time series of chlorophyll-a (Dec / Jan 2002/2012) provided by Marine Biological Laboratory from UFRJ, was used to elaborate the algorithm, coupled with the radiometric data collected by MERIS sensor on concurrent dates with the collections, what allowed the determination of the regression curves that gave rise to algorithms. Several band combinations were used, with emphasis on wavelengths of green, red and near infrared. The algorithm chosen (R = 0.66 and SRM = 77.5%) made use of wavelengths between green and red (665, 680, 560 and 620 nm) and showed satisfactory results, despite the limitations, due to the complexity of the study area and problems in atmospheric correction algorithm. Typical algorithms water Case I (OC3 and OC4) were also tested, as well as FLH MCI and algorithms suggested for water with high concentrations of Chl-a, all with unsatisfactory results. As noted by past studies, Guanabara Bay has high spatial and temporal variability of chlorophyll-a concentrations, with the highest concentrations in the rainy seasons (months: 01, 02, 03, 10, 11, 12) and in the marginal portions (~ 100 mg.m-3), particularly in the western edge of the bay, and lower concentrations in the dry season and in the main circulation channel (~ 20 mg.m-3). This study is a pioneer in the construction and application of bio-optical algorithms for the region of BG using MERIS images. Despite the good results, the algorithm should not be considered definitive, and it is recommended for future work to test different models of atmospheric correction for MERIS images.
156

Life of Photosynthetic Complexes in the Cyanobacterium Synechocystis sp. PCC 6803

January 2011 (has links)
abstract: The cyanobacterium Synechocystis sp. PCC 6803 performs oxygenic photosynthesis. Light energy conversion in photosynthesis takes place in photosystem I (PSI) and photosystem II (PSII) that contain chlorophyll, which absorbs light energy that is utilized as a driving force for photosynthesis. However, excess light energy may lead to formation of reactive oxygen species that cause damage to photosynthetic complexes, which subsequently need repair or replacement. To gain insight in the degradation/biogenesis dynamics of the photosystems, the lifetimes of photosynthetic proteins and chlorophyll were determined by a combined stable-isotope (15N) and mass spectrometry method. The lifetimes of PSII and PSI proteins ranged from 1-33 and 30-75 hours, respectively. Interestingly, chlorophyll had longer lifetimes than the chlorophyll-binding proteins in these photosystems. Therefore, photosynthetic proteins turn over and are replaced independently from each other, and chlorophyll is recycled from the damaged chlorophyll-binding proteins. In Synechocystis, there are five small Cab-like proteins (SCPs: ScpA-E) that share chlorophyll a/b-binding motifs with LHC proteins in plants. SCPs appear to transiently bind chlorophyll and to regulate chlorophyll biosynthesis. In this study, the association of ScpB, ScpC, and ScpD with damaged and repaired PSII was demonstrated. Moreover, in a mutant lacking SCPs, most PSII protein lifetimes were unaffected but the lifetime of chlorophyll was decreased, and one of the nascent PSII complexes was missing. SCPs appear to bind PSII chlorophyll while PSII is repaired, and SCPs stabilize nascent PSII complexes. Furthermore, aminolevulinic acid biosynthesis, an early step of chlorophyll biosynthesis, was impaired in the absence of SCPs, so that the amount of chlorophyll in the cells was reduced. Finally, a deletion mutation was introduced into the sll1906 gene, encoding a member of the putative bacteriochlorophyll delivery (BCD) protein family. The Sll1906 sequence contains possible chlorophyll-binding sites, and its homolog in purple bacteria functions in proper assembly of light-harvesting complexes. However, the sll1906 deletion did not affect chlorophyll degradation/biosynthesis and photosystem assembly. Other (parallel) pathways may exist that may fully compensate for the lack of Sll1906. This study has highlighted the dynamics of photosynthetic complexes in their biogenesis and turnover and the coordination between synthesis of chlorophyll and photosynthetic proteins. / Dissertation/Thesis / Ph.D. Plant Biology 2011
157

Species Discrimination and Monitoring of Abiotic Stress Tolerance by Chlorophyll Fluorescence Transients

MISHRA, Anamika January 2012 (has links)
Chlorophyll fluorescence imaging has now become a versatile and standard tool in fundamental and applied plant research. This method captures time series images of the chlorophyll fluorescence emission of whole leaves or plants upon various illuminations, typically combination of actinic light and saturating flashes. Several conventional chlorophyll fluorescence parameters have been recognized that have physiological interpretation and are useful for, e.g., assessment of plant health status and early detection of biotic and abiotic stresses. Chlorophyll florescence imaging enabled us to probe the performance of plants by visualizing physiologically relevant fluorescence parameters reporting physiology and biochemistry of the plant leaves. Sometimes there is a need to find the most contrasting fluorescence features/parameters in order to quantify stress response at very early stage of the stress treatment. The conventional fluorescence utilizes well defined single image such as F0, Fp, Fm, Fs or arithmetic combinations of basic images such as Fv/Fm, PSII, NPQ, qP. Therefore, although conventional fluorescence parameters have physiological interpretation, they may not be representing highly contrasting image sets. In order to find the effect of stress treatments at very early stage, advanced statistical techniques, based on classifiers and feature selection methods, have been developed to select highly contrasting chlorophyll fluorescence images out of hundreds of captured images. We combined sets of highly performing images resulting in images with very high contrast, the so called combinatorial imaging. The application of advanced statistical methods on chlorophyll fluorescence imaging data allows us to succeed in tasks, where conventional approaches do not work. This thesis aims to explore the application of conventional chlorophyll fluorescence parameters as well as advanced statistical techniques of classifiers and feature selection methods for high-throughput screening. We demonstrate the applicability of the technique in discriminating three species of the same family Lamiaceae at a very early stage of their growth. Further, we show that chlorophyll fluorescence imaging can be used for measuring cold and drought tolerance of Arabidopsis thaliana and tomato plants, respectively, in a simulated high ? throughput screening.
158

Photosynthesis Monitoring in Microalgae Mass Cultures

MALAPASCUA, Jose Romel January 2018 (has links)
This Ph.D. thesis deals with principles of microalgae cultivation in laboratory as well as outdoor aquacultures (Chapter 1) using various cultivation systems and photobioreactors (Chapter 2). Case studies illustrate the main research topic as to correlate changes in growth rate with variation of photosynthetic activity, physiological features and biomass composition (Chapter 3). Special attention was paid to elaboration of protocols of chlorophyll a fluorescence techniques for monitoring the physiology and photosynthetic performance of microalgae mass cultures maintained under various growth conditions (Chapter 4).
159

Variabilidade espacial e temporal das concentrações de clorofila na Baía de Guanabara (RJ) utilizando imagens MERIS e dados in situ / Spacial and temporal variability of the chlorophyll concentration in Guanabara Bay (RJ), using MERIS images and in situ data

Renata De Michielli Grassi 18 August 2014 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este trabalho teve como objetivo principal implementar um algoritmo empírico para o monitoramento do processo de eutrofização da Baía de Guanabara (BG), Rio de Janeiro (RJ), utilizando dados de clorofila-a coletados in situ e imagens de satélite coletadas pelo sensor MERIS, a bordo do satélite ENVISAT, da Agência Espacial Européia (ESA). Para a elaboração do algoritmo foi utilizada uma série histórica de clorofila-a (Out/2002 a Jan/2012) fornecida pelo Laboratório de Biologia Marinha da UFRJ, que, acoplada aos dados radiométricos coletados pelo sensor MERIS em datas concomitantes com as coletas in situ de clorofila-a, permitiu a determinação das curvas de regressão que deram origem aos algorítmos. Diversas combinações de bandas foram utilizadas, com ênfase nos comprimentos de onda do verde, vermelho e infra-vermelho próximo. O algoritmo escolhido (R = 0,66 e MRE = 77,5%) fez uso dos comprimentos de onda entre o verde e o vermelho (665, 680, 560 e 620 nm) e apresentou resultado satisfatório, apesar das limitações devido à complexidade da área de estudo e problemas no algoritmo de correção atmosférica . Algorítmos típicos de água do Caso I (OC3 e OC4) também foram testados, assim como os algoritmos FLH e MCI, aconselhados para águas com concentrações elevadas de Chl-a, todos com resultados insatisfatório. Como observado por estudos pretéritos, a Baia de Guanabara possui alta variabilidade espacial e temporal de concentrações de clorofila-a, com as maiores concentrações no período úmido (meses: 01, 02, 03, 10, 11 12) e nas porções marginais (~ 100 mg.m-3), particularmente na borda Oeste da baia, e menores concentrações no período seco e no canal principal de circulação (~ 20 mg.m-3). O presente trabalho é pioneiro na construção e aplicação de algoritmos bio-óptico para a região da BG utilizando imagens MERIS. Apesar dos bons resultados, o presente algorítmo não deve ser considerado definitivo, e recomenda-se para trabalhos futuros testar os diferentes modelos de correção atmosférico para as imagens MERIS. / This work aimed to implement an empirical algorithm for monitoring the process of eutrophication at Guanabara Bay (BG), Rio de Janeiro (RJ), using in situ chlorophyll-a data and satellite images by MERIS sensor, onboard ENVISAT satellite, from European Space Agency (ESA). A time series of chlorophyll-a (Dec / Jan 2002/2012) provided by Marine Biological Laboratory from UFRJ, was used to elaborate the algorithm, coupled with the radiometric data collected by MERIS sensor on concurrent dates with the collections, what allowed the determination of the regression curves that gave rise to algorithms. Several band combinations were used, with emphasis on wavelengths of green, red and near infrared. The algorithm chosen (R = 0.66 and SRM = 77.5%) made use of wavelengths between green and red (665, 680, 560 and 620 nm) and showed satisfactory results, despite the limitations, due to the complexity of the study area and problems in atmospheric correction algorithm. Typical algorithms water Case I (OC3 and OC4) were also tested, as well as FLH MCI and algorithms suggested for water with high concentrations of Chl-a, all with unsatisfactory results. As noted by past studies, Guanabara Bay has high spatial and temporal variability of chlorophyll-a concentrations, with the highest concentrations in the rainy seasons (months: 01, 02, 03, 10, 11, 12) and in the marginal portions (~ 100 mg.m-3), particularly in the western edge of the bay, and lower concentrations in the dry season and in the main circulation channel (~ 20 mg.m-3). This study is a pioneer in the construction and application of bio-optical algorithms for the region of BG using MERIS images. Despite the good results, the algorithm should not be considered definitive, and it is recommended for future work to test different models of atmospheric correction for MERIS images.
160

Medidor de clorofila na avaliação de nutrição nitrogenada na cultura do alho vernalizado

Lima, Claudinei Paulo de [UNESP] 26 August 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-08-26Bitstream added on 2014-06-13T20:34:26Z : No. of bitstreams: 1 lima_cp_me_botfca.pdf: 904449 bytes, checksum: 0df808d843a75f5c5a193dce30f8b1ab (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conduziu-se dois experimentos, um em ambiente protegido e outro em campo, com o objetivo de avaliar a viabilidade do monitoramento da adubação nitrogenada em cobertura, na cultura do alho vernalizado, através de medidas indiretas do teor de clorofila nas folhas, relacionando-as com o estado nutricional das plantas. Foi adotado o delineamento experimental de blocos ao acaso e os resultados foram submetidos à análise de variância através de regressão, adaptando a melhor equação, através do programa Sisvar, versão 4.2. Os tratamentos utilizados foram: 0, 20, 40, 60, 120, 240 e 360 kg N ha-1, aplicados parceladamente em cobertura aos 30 e 50 dias após a emergência (DAE), tendo sido aplicado 20 t ha-1 de esterco bovino no plantio. Foram realizadas nove avaliações do teor de clorofila e altura das plantas com intervalos de 10 dias entre cada avaliação, iniciando-se aos 20 e finalizando aos 100 DAE. Por ocasião de cada avaliação, foram coletadas duas plantas para análise do conteúdo de nitrogênio e demais nutrientes. Na colheita, após o período de cura, foram obtidos os dados de produção de bulbos, porcentagem de bulbos pseudoperfilhados, índice de formato de bulbos e classificação de acordo com o tamanho. No experimento realizado em campo ocorreu interação entre as doses de nitrogênio e as épocas de avaliação para altura e teor de clorofila. Os maiores valores de altura foram encontrados sem aplicação de nitrogênio e nas épocas mais tardias de avaliações. Os maiores teores de clorofila foram encontrados quando se aplicou a dose de 240 kg ha-1 de nitrogênio, para as épocas avaliadas a maior concentração foi encontrada aos 100 DAE. A concentração de nitrogênio foi influenciada pelas doses e pelas épocas de avaliações, ocorrendo interação entre esses fatores... / Two experiments were carried out, one in a protected environment and another in the field, aiming to evaluate the viability of the sidedress nitrogen management in the vernalizated garlic culture, through indirect measures of the chlorophyll rate in the leaves, relating them with the nutritional state of the plants. The randomized block experimental design was adopted and the results were submitted to Analysis of variance through regression, adapting the best equation through Sisvar program, 4.2 version. The treatments used were: 0, 20, 40, 60, 120, 240 and 360 Kg N ha?£, applied in parts sisedress at 30 and 50 days after emergency (DAE), 20 t ha?£ of bovine manure during planting had been applied. Nine evaluations of the chlorophyll rate and plants height were carried out with 10 days intervals between each evaluation, beginning at 20 and ending at 100 DAE. In each evaluation two plants were collected for nitrogen rates analysis and other nutrients. At harvest, after the cure period, the production bulb data were obtained, secondary growth bulbs percentage, bulb formation index and classification according to the size. In the experiment carried out in the field there was interaction between the nitrogen dose and the dates of height evaluation and chlorophyll rate. The highest values of height were found without nitrogen application and in the latest evaluations. The highest chlorophyll rates were found when 240 Kg ha?£ of nitrogen were applied, for the dates evaluated the highest concentration occurred at 100 DAE. The nitrogen concentration was influenced by doses and dates of evaluation, with interaction between these factors...(Complete abstract click electronic access below)

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