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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.
111

Contamination atmosphérique par les hydrocarbures aromatiques polycycliques : toxicité et devenir du phénanthrène dans des systèmes sol-plante-microorganismes / Atmospheric contamination bu polycyclic aromatic hydrocarbons : toxicity and fate of phenanthrene in soil-plant-microorganism systems

Desalme, Dorine 22 June 2011 (has links)
Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants organiques persistants potentiellement mutagènes et cancérigènes. Leur transfert de l’atmosphère vers les écosystèmes, notamment vers les plantes, conditionne leur entrée dans les chaines alimentaires mais les modalités de ce transfert restent encore mal connues. L’objectif de ce travail était donc de caractériser le transfert et d’identifier les effets biologiques des HAP atmosphériques sur un système sol-plante-microorganismes symbiotiques.Un dispositif expérimental a été conçu afin de recréer en laboratoire une pollution atmosphérique par les HAP avec comme HAP modèle le phénanthrène (PHE). Le dispositif a fait l’objet d’une validation et d’une calibration élaborée de manière originale par une double approche mêlant l’expérimental à la simulation mathématique. Les niveaux d’exposition en polluant (150 µg m-3), contrôlés par des échantillonneurs passifs, se sont avérés pertinents par rapport aux conditions in situ. Ce dispositif a donc été utilisé pour exposer durant un mois des microsystèmes sol-plante-microorganismes au PHE par voie atmosphérique.Les différentes études ont mis en évidence un transfert du PHE depuis l’atmosphère vers tous les compartiments du microsystème, avec une accumulation majeure vers les feuilles de trèfle ou de ray-grass (respectivement 170 et 70 µg g־ ¹MS) et un transfert phloémien vers les racines est suggéré. Chez le trèfle, la mycorhization n’a pas été affectée, tandis que le nombre de nodules actifs a diminué de manière significative. Contrairement aux racines, la biomasse aérienne du trèfle a été significativement affectée (environ – 25%) par l’exposition au PHE atmosphérique, suggérant un impact sur le métabolisme carboné de la plante. Une expérience de marquage des trèfles au ¹³C-CO2 a effectivement montré un impact négatif du PHE atmosphérique sur la croissance, l’allocation de biomasse et l’allocation carbonée. Pour conclure, ces études ont permis non seulement de caractériser les effets biologiques et physiologiques des HAP atmosphériques sur les végétaux mais également de proposer l’utilisation du potentiel mycorhizien comme indicateur de pollution atmosphérique par les HAP. / Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants potentially mutagenic and carcinogenic. Transfer from the atmosphere to ecosystems, especially to plants, conditioning their entry into food chains, but the terms of this transfer are still poorly understood. The aim of this study was to characterize the transfer and identify the biological effects of atmospheric PAHs on soil-plant-symbiotic microorganisms.An experimental device was designed to recreate in the laboratory air pollution with phenanthrene (PHE) as a model PAH. The device was been validated and a calibration developed in an original way by a dual approach combining the experimental mathematical simulation. The levels of exposure to pollutant (150 mg m־³), controlled by passive samplers, were relevant with field conditions. This device has been used to expose a month of the soil-plant micro-organisms in the PHE through the air.Various studies have demonstrated a transfer of PHE from the atmosphere to all compartments of the microsystem, with a major accumulation to leaves in clover or ryegrass (respectively 170 and 70 µg g ־¹ dry weight) and a phloemic transfer to the roots is suggested. In clover, mycorrhization was not affected, while the number of active nodules decreased significantly. Unlike roots, aboveground biomass of clover was significantly affected (approximately – 25%) by exposure to air PHE, suggesting an impact on the carbon metabolism of the plant. A labelling experiment with ¹³C- CO2 in clover has actually shown a negative impact of PHE air on growth, biomass and carbon allocation.In conclusion, these studies have not only characterized the biological and physiological effects of atmospheric PAHs on plants but also proposed the use of mycorrhizal potential as an indicator of air pollution by PAHs.
112

Inativação de indicadores patogênicos em sistemas combinados de tratamento e pré-desinfecção de esgoto sanitário / Inactivation of pathogens tracers in combined systems for sanitary sewer treatment and pre-disinfection

Monaco, Patrícia Bilotta 07 April 2006 (has links)
A proposta apresentada se baseia na introdução de um estágio intermediário de desinfecção previamento ao tratamento biológico visando intensificar os efeitos do estágio seguinte destinado à desinfecção convencional. Para estudo de caso foram aplicadas as técnicas de ozonização e radiação UV combinadas em instalações piloto que simulam duas condições seqüenciais de desinfecção. O desempenho do método proposto foi avaliado através de exames microbiológicos de amostras do efluente anaeróbio previa e posteriormente à desinfecção, utilizando indicadores de contaminação por bactérias (Escherichia coli e coliformes totais), vírus (colifagos) e protozoário (Clostridium perfringens). Os resultados obtidos no sistema combinado pré-desinfecção/desinfecção revelaram eficiência de inativação superior quando comparada ao procedimento convencional. Nas análises de E.coli, por exemplo, a aplicação de apenas 1 mg de ozônio/L ou 51 mW de radiação/'CM POT.2', na primeira etapa de desinfecção, foi suficiente para se alcançar 1 log acima do valor correspondente ao método convencional. Mesmo indicadores mais resistentes como C. perfringens apresentaram redução da fração N/No da ordem de 1 log em relação ao método proposto. Além disso, estes níveis de inativação foram alcançados mesmo sob a influência de elevada concentração de SST, SSV e DQO na entrada na unidade piloto destinada à pré-desinfecção. Entre as seqüências de experimentação investigadas ('O IND.3'/'O IND.3', 'O IND.3'/UV, UV/'O IND.3' e UV/UV) não foram observadas grandes variações. De modo semelhante, os resultados revelaram que a relação N/No, para os indivíduos submetidos ao sistema combinado, não foi afetada pelo aumento no tempo de exposição ao agente inativante ('O IND.3': 5, 7, 10 min; UV: 30, 60, 120s). Considerando as baixas dosagens de 'O IND.3' e UV aplicadas na primeira etapa, somada às condições limitadas de desempenho do sistema real examinado, os níveis de inativação alcançados sugerem grande potencialidade de utilização do método alternativo proposto, comprovando sua viabilidade técnica / The present proposition is based on the introduction of an intermediate disinfection stage before the biological treatment, in order to intensify the effects of the next stage employed in conventional disinfection. Studies were performed using combined ozonization and UV radiation techniques, in a model installation that simulates two sequential disinfection conditions. The performance of the method was evaluated using microbiological exams of samples taken from the anaerobic effluent before and after the disinfection. Bacterial (Escherichia coli and total coliforms), viral (coliphages) and protozoan (Clostridium perfringens contamination tracers were used in such exams. Results obtained by combining pre-disinfection and disinfection reveal superior inactivation efficiency as compared to the conventional procedure. For example, in the E. coli analysis the application of only 1 mg of ozone/L or 51 mW/'CM POT.2' of radiation in the first disinfection stage was enough for achieving 1 log above the convention method. Even more resistant tracers, such as C. perfringens, showed aproximatelly 1 log of reduction in the N/No fraction in the proposed method. Besides, these inactivation levels were achieved even for high concentrations of SST, SSV and DQO in the entrance of the pre-disinfection unit. No significant variations were observed among the disinfection sequences ('O IND.3'/'O IND.3','O IND.3'/UV,UV/'O IND.3', and UV/UV). Similarly, the results showed that the N/No relation, for individuals submitted to the combined system, was not affected by the increase of the exposition time to the inactivation agent ('O IND.3': 5, 7, 10 min; UV: 30, 60, 120 s). Taking into account the low dosages of 'O IND.3' and UV applied in the first stage and the limited performance conditions of the real system, the achieved inactivation levels suggest a great potential for the alternative method proposed, demonstrating its technical viability
113

Spectroscopie moléculaire : calcul de spectres, mesures des températures de rotation et de vibration dans les plasmas thermiques

Faure, Géraldine 05 December 1997 (has links) (PDF)
Ce travail porte sur le diagnostic des températures de vibration et de rotation des molécules dans les plasmas thermiques.<br /><br />Ce mémoire comporte deux grandes parties : l'une concerne le calcul de spectres moléculaires et la deuxième partie est consacrée à la comparaison des spectres dans quatre cas expérimentaux différents.<br /><br />Un code de calcul a été réalisé pour simuler des spectres d'espèces diatomiques. Ce code a été essentiellement appliqué aux radicaux C2, CN, à la molécule N2 et à l'ion N2+ avec comme paramètres variables les températures de vibration et de rotation. Cette partie commence par une description de la molécule diatomique et de ses propriétés. <br />Ensuite la méthode pour calculer les spectres est explicitée : <br />détermination des longueurs d'onde,<br />de leur intensité,<br />application d'une fonction d'appareil,<br />obtention du spectre final. <br />L'influence des températures de rotation et de vibration sur les intensités des raies est prise en compte ainsi que celle de la fonction d'appareil. Ces spectres sont calculés, pour une expérience donnée, de manière à déterminer ces deux paramètres par comparaison avec les spectres obtenus par la mesure.<br /><br />Cette méthode a été utilisée sur quatre plasmas différents : <br />une flamme oxy-acétylénique,<br />un arc stabilisé dans une chambre de Maecker,<br />une torche à plasma ICP,<br />une décharge entre deux électrodes liquides. <br />Les températures de rotation et de vibration ont été déterminées par la comparaison de spectres. Ainsi des profils de températures ont pu être réalisés.<br /><br />En annexe, les valeurs numériques nécessaires aux calculs de spectres sont répertoriées pour le système de Swan de C2, le système violet de CN, le second système positif de N2 et le premier système négatif de N2+.
114

Violet Archer’s “The Twenty-Third Psalm” (1952): An Analytical Study of Text and Music Relations through Fibonacci Numbers, Melodic Contour, Motives, and Piano Accompaniment

Wan, Jessica J 27 September 2012 (has links)
This study explores text and music relations in Canadian composer Violet Archer’s “The Twenty-Third Psalm” by analysing the text of Psalm 23, Fibonacci numbers, melodic contours, motives, and the role of the accompaniment. The text focuses on David’s faith in God and his acceptance of God as his shepherd on earth. The four other approaches allow us to examine the work on three different structural levels: background through Fibonacci numbers, middleground through melodic contour analysis, and foreground through motivic analysis and the role of the accompaniment. The measure numbers that align with Fibonacci numbers overlap with some of the melodic contour phrases, which are demarcated by rests, as well as with the most important moments at the surface level, such as the emphasis on the word “death” through recurring and symbolic motives. The piano accompaniment further supports these moments in the text.
115

Subjects Matter : The Subject-Object Dichotomy in Toni Morrison's Jazz

Gustavsson, Jonas January 2012 (has links)
This essay examines the subject-object dichotomy between men and women in Toni Morrison’s Jazz and the thesis of the essay is that this dichotomy develops into subject-object harmony. Through Simone de Beauvoir’s theory regarding the subject-object dichotomy and a close reading of the novel, this essay concludes that Jazz shows the possibility of reciprocal relationships built on friendship. In other words, the dichotomy changes into harmony, which makes it possible for both men and women to reach freedom and fulfilment in transcendence.
116

Preparação de protetores solares com argila: análise da eficácia in vitro da propriedade fotoprotetora.

COSTA, Joneuso Tércio Cavalcanti da. 28 June 2018 (has links)
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-28T20:35:34Z No. of bitstreams: 1 JONEUSO TÉRCIO CAVALCANTI DA COSTA – DISSERTAÇÃO (UAEMa) 2015.pdf: 1493605 bytes, checksum: 64e995b963519b1073063638b52caeac (MD5) / Made available in DSpace on 2018-06-28T20:35:34Z (GMT). No. of bitstreams: 1 JONEUSO TÉRCIO CAVALCANTI DA COSTA – DISSERTAÇÃO (UAEMa) 2015.pdf: 1493605 bytes, checksum: 64e995b963519b1073063638b52caeac (MD5) Previous issue date: 2015-08-27 / As radiações não ionizantes (UV-A; UV-B e UV-C) do espectro eletromagnético do sol causam doenças aos seres humanos e precisam ser evitadas. O uso adequado do protetor solar minimiza tal risco. Atualmente, a tendência é introduzir materiais naturais, orgânicos ou inorgânicos, na composição dos protetores solares (fotoprotetores), no afã de neutralizar possíveis efeitos colaterais dos materiais sintéticos. Estudos mostraram que argilas (silicatos em camadas) incorporadas aos protetores solares podem bloquear radiação ultravioleta no comprimento de onda entre 250 a 400 nm dependendo da composição da argila. Acompanhando essa linha norteadora é que se baseou a elaboração deste trabalho onde duas argilas foram empregadas na preparação de fotoprotetores e aferida a eficácia em laboratório da Universidade Federal de Campina Grande (UFCG) através da avaliação in vitro por espectrofotometria. As argilas testadas foram a montmorilonita sódica comercial (Cloisite® Na + ) e a bentonítica Argel 35. As formulações foram preparadas em três farmácias de manipulação, em três cidades diferentes, Guarabira, João Pessoa e Campina Grande, no Estado da Paraíba. O método escolhido para avaliação do Fator de Proteção Solar (FPS) foi o método in vitro desenvolvido por Mansur em virtude da ótima correlação com método in vivo, além de apresentar outras vantagens a exemplo do baixo custo e o de se evitar exposição do ser humano a experimentos que possam causar danos à saúde. Antes de avaliar o FPS das formulações preparadas com as argilas foi feita a avaliação do FPS de protetores solares comerciais e foi confirmado que o método in vitro utilizado foi adequado na determinação do FPS de protetores solares. A introdução de argilas na composição dos protetores solares, como materiais naturais, em substituição ao material sintético TiO2 foi eficaz, especialmente para a argila bentonita Argel. A legitimidade em se estudar o efeito fotoprotetor dos materiais argilosos na composição dos protetores solares é justificada por grande relevância social, posto que são de baixo custo, e ainda por serem encontradas com facilidade na natureza. / Non-ionizing radiation (UV-A, UV-B and UV-C) of the sun's electromagnetic spectrum cause diseases to human and must be avoided. The proper use of sunscreen minimizes this problem. Currently, the trend is to introduce natural materials, organic or inorganic, in the composition of sunscreens, in order to neutralize possible side effects of synthetic materials. Studies have shown that clays (layered silicates) incorporated in sunscreens can block ultraviolet radiation in 250 to 400 nm wavelength range depending on the clay composition. Following this guideline, in this work, two clays were used in the preparation of sunscreen and its effectiveness was determined at Universidade Federal de Campina Grande (UFCG) laboratory through in vitro evaluation by spectrophotomery. The clays tested were Cloisite® Na + sodium montmorillonite and Argel 35 bentonite. The formulations were prepared in pharmacies in three different cities, Guarabira, Joao Pessoa and Campina Grande, in Paraíba state. The method chosen to evaluate the Sun Protection Factor (SPF) was in vitro method, developed by Mansur, due to the excellent correlation with in vivo method. Besides, there are other advantages like low cost and less damage to health since the volunteer is not exposed to the experiments. Before the evaluation of SPF of prepared formulations with the clay, the SPF of commercial sunscreens was determined and it was confirmed that the in vitro method was proper to define sunscreen SPF. The introduction of clay in the sunscreens composition, as natural materials, replacing TiO2 synthetic material was effective, especially for Argel bentonite clay. The legitimacy of studying the photoprotective effect of clay materials in the composition of sunscreens is justified by great social relevance, since they are inexpensive and found easily in nature.
117

Acute Astrogliosis and neurological deficits following repeated mild traumatic brain injury

Clarkson, Melissa A. 04 September 2018 (has links)
Mild traumatic brain injury (mTBI), often referred to as concussion, has become increasingly recognized as a serious health issue in the general population. The prevalence of mTBI in athletes, particularly repeated injuries in young athletes, is of great concern as injuries to the developing brain can have long-term detrimental effects. In this study we used a novel awake closed-head injury (ACHI) model in rodents to examine repeated mTBI (rmTBI), to determine if repeated injuries produced the neurological and molecular changes evident with human concussion. Animals were administered 4, 8, and 16 rmTBIs and acute neurological assessments were performed after the injuries. Changes in glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (Iba-1) levels were assessed using Western blot analysis at one day following rmTBI in the ipsilateral dentate gyrus (DG) and the cornu ammonis (CA) regions of the hippocampus and the cortex (CX) indicative of astrocyte and microglial cell reactivity. Results indicated that the ACHI model produces neurological deficits immediately after the injuries, with the most deficits arising in the rmTBI16 group. Despite deficits in all injury groups, histological staining with cresyl violet revealed no significant morphological tissue damage to the brain. Western blot analysis, however, showed a significant increase in DG and CX GFAP expression in the rmTBI16 group with no changes in Iba-1 levels. This suggests an acute activation of astrocytes in response to injury, with a delay or absence of microglial activation. Our findings show that with repetitive concussions, we are able to detect acute neurological and molecular changes in the juvenile female brain. However, further investigation is necessary to determine if these are transient changes. / Graduate
118

The subaltern `speaks': agency in Neshani Andreas' The purple violet of Oshaantu

Rhode, Aletta Cornelia 30 November 2003 (has links)
This dissertation critically evaluates the issue of the `silencing' of the subaltern woman in the 1988 version of Gayatri Spivak's essay `Can the Subaltern Speak?' The conclusions reached are then related to the novel The Purple Violet of Oshaantu by the Namibian woman writer Neshani Andreas. Chapter 1 deals with the essay `Can the Subaltern Speak?' and the `silenced' subaltern woman, examining both Spivak's theory on this issue as well as criticism of this theory by different postcolonial theorists. Chapter 2 presents aspects of both the creative and political practice of women, specifically the woman writer, in certain countries in Africa. Chapter 3 deals with the novel The Purple Violet of Oshaantu by Neshani Andreas and explores issues like the `silencing' of the subaltern women in the novel, opposition to patriarchal oppression and the engendering of agency by both the writer and the characters in the novel. / English Studies / M. A. (English)
119

Validation of two bio-analytical assays for the measurement of hydrophilic antioxidant in several food and beverage commodities in accordance with ISO 17025 regulatory guidelines

Parbhunath, Olivia Leshia January 2013 (has links)
Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Biomedical Technology in the Faculty Health and Wellness Sciences at the Cape Peninsula University of Technology, 2013 / The accurate and consistent measurement of antioxidants is crucial to evaluating their biological role in the prevention and delay of cancer and other pathological conditions. Hence, the performance of the analytical method utilized should be evaluated for acceptable levels of accuracy, precision and other performance parameters according to internationally accepted standards. Additionally, the measure and influence of existing errors should be evaluated and the method optimized to reduce such errors. In furtherance of this vital aim, this research project sought out to optimize and validate two bio-analytical assays for the measurement of total antioxidant capacity and L-ascorbic acid (L-AA), respectively in food commodities. The validation procedure was performed in accordance with ISO 17025 international standard. The first study in this thesis evaluated, optimized and validated the hydrophilic oxygen radical absorbance capacity (H-ORACFL) assay using fluorescein for total antioxidant capacity in various food and beverage products. The assay demonstrated good results with regard to accuracy, precision, linearity, specificity, limits of detection (LOD) and quantification (LOQ) and robustness. The extraction solvent (60% ethanol) recovered excellent antioxidant yields for most samples tested. The optimization of the method in terms of temperature and sample usage on the micro-plate significantly (p<0.05) reduced errors and subsequently improved precision substantially.
120

Inativação de indicadores patogênicos em sistemas combinados de tratamento e pré-desinfecção de esgoto sanitário / Inactivation of pathogens tracers in combined systems for sanitary sewer treatment and pre-disinfection

Patrícia Bilotta Monaco 07 April 2006 (has links)
A proposta apresentada se baseia na introdução de um estágio intermediário de desinfecção previamento ao tratamento biológico visando intensificar os efeitos do estágio seguinte destinado à desinfecção convencional. Para estudo de caso foram aplicadas as técnicas de ozonização e radiação UV combinadas em instalações piloto que simulam duas condições seqüenciais de desinfecção. O desempenho do método proposto foi avaliado através de exames microbiológicos de amostras do efluente anaeróbio previa e posteriormente à desinfecção, utilizando indicadores de contaminação por bactérias (Escherichia coli e coliformes totais), vírus (colifagos) e protozoário (Clostridium perfringens). Os resultados obtidos no sistema combinado pré-desinfecção/desinfecção revelaram eficiência de inativação superior quando comparada ao procedimento convencional. Nas análises de E.coli, por exemplo, a aplicação de apenas 1 mg de ozônio/L ou 51 mW de radiação/'CM POT.2', na primeira etapa de desinfecção, foi suficiente para se alcançar 1 log acima do valor correspondente ao método convencional. Mesmo indicadores mais resistentes como C. perfringens apresentaram redução da fração N/No da ordem de 1 log em relação ao método proposto. Além disso, estes níveis de inativação foram alcançados mesmo sob a influência de elevada concentração de SST, SSV e DQO na entrada na unidade piloto destinada à pré-desinfecção. Entre as seqüências de experimentação investigadas ('O IND.3'/'O IND.3', 'O IND.3'/UV, UV/'O IND.3' e UV/UV) não foram observadas grandes variações. De modo semelhante, os resultados revelaram que a relação N/No, para os indivíduos submetidos ao sistema combinado, não foi afetada pelo aumento no tempo de exposição ao agente inativante ('O IND.3': 5, 7, 10 min; UV: 30, 60, 120s). Considerando as baixas dosagens de 'O IND.3' e UV aplicadas na primeira etapa, somada às condições limitadas de desempenho do sistema real examinado, os níveis de inativação alcançados sugerem grande potencialidade de utilização do método alternativo proposto, comprovando sua viabilidade técnica / The present proposition is based on the introduction of an intermediate disinfection stage before the biological treatment, in order to intensify the effects of the next stage employed in conventional disinfection. Studies were performed using combined ozonization and UV radiation techniques, in a model installation that simulates two sequential disinfection conditions. The performance of the method was evaluated using microbiological exams of samples taken from the anaerobic effluent before and after the disinfection. Bacterial (Escherichia coli and total coliforms), viral (coliphages) and protozoan (Clostridium perfringens contamination tracers were used in such exams. Results obtained by combining pre-disinfection and disinfection reveal superior inactivation efficiency as compared to the conventional procedure. For example, in the E. coli analysis the application of only 1 mg of ozone/L or 51 mW/'CM POT.2' of radiation in the first disinfection stage was enough for achieving 1 log above the convention method. Even more resistant tracers, such as C. perfringens, showed aproximatelly 1 log of reduction in the N/No fraction in the proposed method. Besides, these inactivation levels were achieved even for high concentrations of SST, SSV and DQO in the entrance of the pre-disinfection unit. No significant variations were observed among the disinfection sequences ('O IND.3'/'O IND.3','O IND.3'/UV,UV/'O IND.3', and UV/UV). Similarly, the results showed that the N/No relation, for individuals submitted to the combined system, was not affected by the increase of the exposition time to the inactivation agent ('O IND.3': 5, 7, 10 min; UV: 30, 60, 120 s). Taking into account the low dosages of 'O IND.3' and UV applied in the first stage and the limited performance conditions of the real system, the achieved inactivation levels suggest a great potential for the alternative method proposed, demonstrating its technical viability

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