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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.
181

Understanding the Role of Emotions in Mediated Intergroup Threat: A Cultivation and Appraisal Theory Approach

Seate, Anita January 2012 (has links)
This investigation sought to extend research in mediated intergroup communication by examining the role of emotion in producing intergroup bias. Two studies were guided by social identity theory, appraisal-based theories of emotion, and cultivation theory. Study 1 surveyed 254 adults, recruited through student referrals. Drawing insight from previous content analytic research and cultivation theory, results indicated that the media plays an important role in cultivating emotional reactions toward racial minorities. Overall daily television consumption was associated with experiencing anxiety-related emotions and distrust-related emotions toward Blacks. Television news consumption was associated with experiencing anger towards Blacks. Overall daily television consumption was associated with experiencing anger and anxiety-related emotions toward Latinos and Asians. Television news consumption was associated with experiencing distrust-related emotions toward Asians. In Study 2 a 2 (Immigration: Threat/No-Threat) X 2 (Ingroup Emotional Norm Endorsement: Present/Absent) plus 1 (Control) experiment examined the impact of mediated intergroup threat on attitudes toward immigration, collective self-esteem, information sharing and seeking behaviors, and policy support, in the context of illegal immigration. This study also examined whether experimental condition indirectly influenced the above-specified outcomes through intergroup emotions. Previous news consumption was examined as a potential moderator of the mediational relationship between experimental condition and intergroup outcomes via intergroup emotions. Results indicate that exposure to intergroup threat via the media directly influence attitudes toward immigrants' human rights and information sharing. Exposure to intergroup threat indirectly influences immigration attitudes through feelings of anxiety. Moreover, exposure to intergroup threat via the media indirectly influences information sharing and support for English-only legislation through feelings of disgust. Conditional indirect effects were found for immigration attitudes, information sharing, and support for English-only legislation. Exposure to threatening intergroup information neither directly, nor indirectly information seeking or emailing congressperson to reduce the number of immigrants allowed in the United States. Results are discussed in light of social identity theory, intergroup threat theory, intergroup emotions theory, and BIAS map research. Taken together, results suggest that the current study's social identity appraisal-based approach provides insight into the role of media in intergroup processes.
182

Cultivation Optimization and Modeling for Microalgae to Produce Biodiesel

Ren, Ming January 2012 (has links)
Microalgae has shown to be an ideal choice for biofuel industry. Algae has high oil productivity, a short growth cycle and survives in a wide variety of water sources including high salinity and waste water. For this project, four different species of marine microalgae were screened based on oil content. They were Dunaliella tertiolecta (CCMP364), Nannochloropsis gaditana (CCMP527), Tetraselmis sp (CCMP 908) and Nannochloropsis salina (CCMP1776). Experimental results showed that CCMP 527 and 1776 strains had higher lipid content and better fatty acids profile than the other two. Further investigations were carried on CCMP 527 in order to maximize biomass productivity and lipid content. Nutrients, salinity, pH, temperature, light intensity and aging of the culture can all affect both lipid content and fatty acid profile and were investigated. Nutrient stress is the easiest way to manipulate lipid composition and increase lipid content. Hence, various carbon and nitrogen sources were investigated to determine the range and amount of substrates that may be feasible for cultivation. For supplying lipid for biodiesel production, the optimum culture conditions for strain Nannochloropsis gaditana are using CO₂ enriched air bubbling, f/2-Si medium, pH control, and nitrate as the nitrogen source. Use of other fertilizers is feasible as well, however, the nitrogen source greatly affects lipid productivity, but trace amounts of organics in ground water do not.A model which predicts cell growth, nitrogen concentration, and lipid yield in batch systems is developed that is applicable for low nitrogen conditions. Plus, a sensitivity analysis of three major parameters was done to validate how variations in these key parameters affect simulation results. The fatty acid profile as a function of time was shown not to vary from mid-exponential to stationary phase. The model describes reactor behavior well, therefore it can be applied to the genus of Nannochloropsis to predict biomass yield and lipid accumulation, and be a useful tool to optimize and compare bioreactor systems for the biofuel industry. In addition, effects of nitrate and urea under repletion condition on microalgae growth, lipid yield and fatty acids profile for microalgae Nannochloropsis gaditana were investigated. Replacing nitrate by urea didn't show positive influence on lipid content and yield compared to normal medium. The major fatty acids for these two mediums were palmitic acid (C16:0) and palmitioleic acid (C16:1). Nannochloropsis gaditana still shows to be ideal candidate for biodiesel production using urea or nitrate enriched agriculture wastewater.
183

Agriculture, ecology and domestic organization among the Kekchi Maya

Wilk, Richard Ralph, Wilk, Richard Ralph January 1981 (has links)
No description available.
184

INDUCTION OF CELLULASE IN HIGH SOLIDS CULTIVATION OF <em>TRICHODERMA REESEI</em> FOR ENHANCED ENZYMATIC HYDROLYSIS OF LIGNOCELLULOSE

Empson, Danielle 01 January 2016 (has links)
This project aimed investigated cellulase in-situ production for large-scale on-farm production of lignocellulosic biofuel. Cellulase activity and glucose released by T. reesei with corn stover and wheat bran as co-substrates for solid state cultivation (SSC) were examined. Co-cultivation has previously increased T. reesei cellulase, but corn stover and wheat bran have not been co-cultivated (Dhillon, Oberoi et al. 2011). This work compared cellulase activity and glucose concentration of corn stover co-cultivated with 0-40% wheat bran in high solids. Samples with at least 20% wheat bran exhibited increased cellulase activity. However, the average glucose concentration without wheat bran was 3.29 g/L compared to 16.7 g/L with wheat bran. Glucose released by T. reesei on pretreated corn stover with 0-40% wheat bran was compared at the optimal temperatures for fungal growth and for cellulase activity after SSC. Previous research has rarely used cellulase from SSC to hydrolyze lignocellulose. Following SSC of T. reesei at 30°C for seven days, samples were warmed to 50°C for five days. Glucose concentration increased to 12.1 and 32.7 g/L for samples with and without wheat bran. This strategy could reduce lignocellulosic fuel production costs by eliminating need for commercial cellulase and is promising for efficient cellulose hydrolysis.
185

The construction and evaluation of a novel tubular photobioreactor at a small pilot plant scale

Kutama, Makonde 07 1900 (has links)
M. Tech (Biosciences, Faculty of Applied and Computer Sciences), Vaal University of Technology. / The mass production of algae for commercial purposes has predominately been carried out in open ponds systems. However, open ponds systems have a number of disadvantages such as poor light utilization, requirement for large areas of land and high risks of contamination. On the other hand, photobioreactors have attracted much interest because they allow a better control of the cultivation conditions than open systems. With photobioreactors, higher biomass productivities are obtained and contamination can be easily prevented. Photobioreactors can also be engineered to manipulate the light and dark photosynthetic reactions thus enhancing biomass productivity. The main objective of this study was to construct a novel tubular photobioreactor which had the ability to expose the cultured alga to light and dark phases with the aim of optimizing the algal biomass production. A novel tubular photobioreactor with the ability to manipulate the cultured alga’s light and dark photosynthetic reactions was constructed in this study. The alga Spirulina platensis was chosen as the test organism in this novel tubular photobioreactor due to a number of reasons such as its globally socioeconomic importance, its tolerance of higher pH and temperature values which makes it almost impossible to contaminate. The cultivation process of Spirulina in the photobioreactor was investigated through alternating light and dark cycles in an attempt to increase the photosynthetic efficiency of the culture. The effect of different light intensities on the growth of Spirulina in the novel tubular photobioreactor was investigated and it was found that the best light condition that favored higher biomass formation was at 600 μ mol m-2 s-1. Five different light/ dark ratios were evaluated at a light intensity of 600 μ mol m-2 s-1 during a batch mode of operation of the novel tubular photobioreactor. The light/ dark ratio of 1:0.25 was found to be the best ratio because it gave the highest biomass in the shortest period of time when compared to the other ratios used. These results seem to suggest that longer light cycle relative to dark cycle results in higher biomass production. The ratio of 1:0.25 was then used to operate the novel tubular photobioreactor in a continuous mode. A maximum biomass productivity of 25 g/m2/day was achieved which corresponded to a net photosynthetic efficiency of 5.7 %. This result was found to be higher than what most photobioreactors could achieve but it was 2.8 g/m2/day lower than the highest ever reported productivity in a photobioreactor when Spirulina is cultivated. The 2.8 g/m2/day lower was attributed to the different materials used in the construction of these two photobioreactors. The photobioreactor which achieved 27.8 g/m2/day was made up of a clear glass whereas the novel tubular photobioreactor was made up of a PVC tubing. PVC tubes tend to change from clear to a milky colour after a certain period when it is used at higher temperature and pH values hence blocks a certain amount of light. Therefore the main recommendation in this study is to use a PVC tubing with a longer life span when used at a higher temperature and pH values.
186

Využití kultivačních metod v diagnostice zánětů mléčné žlázy ve vybraném chovu dojnic

ULMOVÁ, Kateřina January 2019 (has links)
The goal of my thesis was to evaluate origin of mastisis diseases and specify the best way to cure this disease with antibiotics. Secondary goal was to examin origin of things that cause these diseases, efficiency of the cure and how it is influenced by the stage of the illness. This research was made in cowshed, fron april to december 2018 with 136 specimen. During this period I took samples of milk, that had more than 800 000 somatic cells in 1ml of milk. Based of possitve NK test, samples of mammary gland were taken and cultivated on one used only Petri dish. Depending of the origin of the infection, the proper atibitics were chosen for the cure. After 7 to 14 days after antibiotics treatment, milk sample was taken from the cured part od mammary gland and It was tested to see, if the treatment was successful. 77% of the specimen were sick because of microorganisms and most of the specimen were afflicted the most during 1st lactation (36.8% to 47.1%). Following microorganisms caused mastisis - Staphylococcus spp. (KNS), Streptococcus uberis, Klebsiella oxytoca, Escherichia coli, Candida rugosa a Enterococcus faecalis. 36% of mastisis was caused by Staphylococcus spp. (KNS), followed by coliform bacteria (22%). 17% of mastisis was caused by Streptococcus uberis. 10.5% of specimen was infected by Enterococcus faecalis. Candida rugosa was found in 7.4% of the samples and in 9.5% of samples the diseasehad no specific microorganism responsible. From 105 infected cows, 68% of them fully recovered. At the end, based on the stage of the mastisis, efectivness of the treatmend was statistically evaluated. The evaluation showed, that stage of infection massively influence the result of the treatment.
187

Palaeoecological Evidence of Ecosystem Dynamics in Sumatra, Indonesia. Case Studies of Tropical Submountains and Mangroves

Setyaningsih, Christina Ani 02 July 2018 (has links)
No description available.
188

Estudo fitossociológico e interferência das plantas daninhas na nutrição e produtividade do quiabeiro /

Bachega, Ligia Pecoriello Saes. January 2011 (has links)
Resumo: O presente trabalho foi conduzido com o objetivo de se determinar os períodos de interferência das plantas daninhas na cultura do quiabo cv. "Santa Cruz 47" e seus efeitos no acúmulo de macronutrientes da cultura. Os tratamentos consistiram em períodos crescentes de convivência e controle das plantas daninhas: aos 7, 14, 21, 28, 35, 42, 49, 63, 77, 91 e 105 dias após a emergência (DAE), totalizando vinte e dois tratamentos, dispostos em blocos casualizados, com três repetições cada. As principais espécies de plantas daninhas responsáveis pela interferência na cultura foram Portulaca oleracea, Eleusine indica e Nicandra physaloide. A convivência do quiabeiro com as plantas daninhas por todo o ciclo de cultivo reduziu a produtividade da cultura em 95%. O período anterior à interferência foi de 57 DAE, enquanto o período total de prevenção à interferência foi de 14 DAE. Não houve período crítico de prevenção à interferência, sendo que um único controle das plantas daninhas entre 14 e 57 DAE é suficiente para prevenir a interferência na cultura do quiabo. A competição com plantas daninhas reduziu drasticamente o acúmulo de matéria seca pela cultura, assim como o acúmulo de macronutrientes / Abstract: The experiment was carried out to determine the critical periods of interference of the weeds on the okra crop cv. "Santa Cruz 47" and the effects on macronutrients uptake. The treatments were weedy and weed-free increased weekly periods: at 7, 14, 21, 28, 35, 42, 49, 63, 77, 91 and 105 days after emergence (DAE), totaling twenty two treatments, arranged in a randomized block design, with three replications. The main weed species responsible for interference in culture were Portulaca oleracea, Eleusine indica and Nicandra physaloides. Coexistence of okra crop and weeds throughout the season reduced crop yield by 95%. Period before interference was 57 DAE, while total period of interference prevention was 14 DAE. There was no critical period of interference prevention, so that a single weed control between 14 and 57 DAE is sufficient for interference prevention in okra crop. The competition with weeds reduced the dry matter accumulation in culture, as well as the accumulation of nutrients / Orientador: Silvano Bianco / Coorientador: Arthur Bernardes Cecílio Filho / Banca: Pedro Luís da Costa Aguiar Alves / Banca: Sally Ferreira Blat / Mestre
189

Caracterização da comunidade bacteriana contaminante do processo fermentativo para produção de etanol e o impacto no metaboloma da fermentação / Characterization of contaminating bacterial community from ethanol fermentation process and the impact on the metabolome

Bonatelli, Maria Letícia 30 September 2016 (has links)
O processo fermentativo da Saccharomyces cerevisiae para a produção de etanol tem grande relevância para o Brasil por ser responsável por uma fonte de energia renovável que é amplamente usada na indústria automotiva. No entanto, em escalas industriais, a fermentação da levedura não ocorre em ambiente asséptico, sendo que diferentes micro-organismos contaminantes são capazes de crescer, competir por nutrientes e até mesmo interferir na fermentação da S. cerevisiae. A fim de melhor compreender quem são os micro-organismos contaminantes e o que fazem na dorna de fermentação, foi utilizado uma abordagem polifásica. O levantamento da microbiota bacteriana presente nas usinas do estado de São Paulo foi realizado através de técnicas independentes de cultivo. Posteriormente, foram realizados ensaios fermentativos com S. cerevisiae CAT-1 na presença do contaminante Lactobacillus fermentum (I-2) para a análise da interação destes na dorna de fermentação. A análise foi realizada por metabolômica acessada através da cromatografia gasosa acoplada a espectrometria de massas (GC-MS) e, para isso, inicialmente foi estabelecida uma metodologia eficiente para análise através de GC-MS. Nas usinas, foi reportada uma porcentagem de Lactobacillus maior do que a descrita e a população bacteriana pareceu ser característica de cada usina e persistente ao longo do tempo. Já o estabelecimento da metodologia de análise de metabólitos da fermentação por GC-MS possibilitou a identificação de 261 metabólitos, e as três classes mais abundantes foram Carbohydrates and carbohydrate conjugates (16%), Carboxylic acids and derivatives (12%) e Fatty Acyls (5%). E no ensaio de S. cerevisiae CAT-1 na presença do contaminante L. fermentum (I-2), possibilitou a identificação de 208 metabólitos, onde 50 foram diferencialmente abundantes. Além disso, a via glicolítica foi reforçada na fermentação de S. cerevisiae CAT-1, sendo que nas fermentações de S. cerevisiae (CAT-1) na presença de L. fermentum (I-2), a produção de aminoácidos a partir do glutamate pareceu ser importante. Desta forma, uma análise polifásica pode auxiliar no esclarecimento da relação dos micro-organismos contaminantes com a levedura dentro da dorna de fermentação. / The fermentation of Saccharomyces cerevisiae for ethanol production has great importance to Brazil since it is responsible for the production of a renewable energy source that is widely used in the automotive industry. However, in industrial scale, the yeast fermentation does not occur in an aseptic environment, where different contaminant microorganisms are capable of growing, competing for nutrients and even interfering with the S. cerevisiae fermentation. In order to better understand who the contaminating microorganisms are and what they do in the fermenter, it was used one polyphasic approach. The survey of the bacterial microflora present in two different São Paulo state distilleries was carried out by cultivation independent techniques. Subsequently, fermentation assays were performed with S. cerevisiae CAT-1 in the presence of the contaminant Lactobacillus fermentum (I-2) to analyze the interaction of these microorganisms in the fermenter. The analysis was performed through metabolomics accessed by gas chromatography-mass spectrometry (GC-MS) and, for that, initially was established an efficient methodology for fermentation metabolite analysis by GC-MS. In the distilleries, it was reported a higher percentage of Lactobacillus than ever described and bacterial population appeared to be characteristic of each distillery and persistent over time. After the establishment of fermentation metabolite analysis methodology by GC-MS, it was possible to identify 261 metabolites, and the three most abundant classes were Carbohydrates and carbohydrate conjugates (16%), Carboxylic acids and derivatives (12%) and Fatty acyls ( 5%). In the fermentation assay of S. cerevisiae CAT-1 in the presence of the contaminant L. fermentum (I-2), it was possible to identify 208 metabolites, where 50 were differentially abundant. In addition, the glycolytic pathway was enhanced in the fermentation of S. cerevisiae CAT-1, and in fermentation of S. cerevisiae (CAT-1) in the presence of L. fermentum (I-2), the production of amino acids from glutamate appeared to be important. Thus, a polyphasic analysis can help in the understanding of the relationship between contaminating microorganisms with the yeast in the fermenter.
190

Os anos de aprendizado de Wilhelm Meister e as formas de individualismo dos séculos XVIII e XIX / Wilhelm Meisters Apprenticeship and the forms of individualism of XVIII and XIX centuries.

Pires, Pedro Giovanetti Cesar 26 September 2014 (has links)
Esta pesquisa propõe-se investigar o romance Os anos de aprendizado de Wilhelm Meister, de Johann Wolfgang von Goethe (1749-1832), publicado em 1796. Nosso objetivo é realizar, com a análise do romance, uma reconstrução sociológica da noção de formação do indivíduo expressa na obra, articulando-a com o processo de emeregência da noção moderna de liberdade individual. Para tanto, recorre-se a três conceitos-chave do pensamento de Georg Simmel: o conceito de cultura, individualismo quantitativo e individualismo qualitativo. Ao relacionar o enredo do romance com as transformações na estrutura social ocorridas nos séculos XVIII e XIX, as quais são analisadas a partir dos conceitos de Simmel, nosso objetivo é esclarecer a visão de modernidade que se apresenta na obra de Goethe, bem o seu potencial crítico relativo à questão da liberdade individual. / This research aims to investigate the novel Wilhelm Meisters Apprenticeship by Johann Wolfgang von Goethe (1749-1832), published in 1796. Our goal is to build, with the analysis of the novel, a sociological reconstruction from the idea of individual self-cultivation which the novel express and articulate this idea with the process of construction of the modern individual freedom ideal. To perform that, this research uses three key-concepts from Georg Simmel: the concept of culture, quantitative individualism and qualitative individualism. By relating the novels story with the changes of the social structure in the XVIII and XIX centuries, our objective is to clarify the vision of modernity from Goethes novel, as well explore its critical potential on the subject of individual freedom.

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