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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.
31

The Impact of the US Interest Rate Movement on the Global Stock and Commodity Markets

Yeh, Chao-kun 15 July 2008 (has links)
This research would like to study the influence that US has on the global market by proving the global stock and commodity markets are correlated to the Fed's interest rate policy. Meanwhile, hope this research can help investors to evaluate the market trend and make appropriate investment decision. we look into detail by examining the correlation between the US stock market and different periods of rate hike, rate cut and neutral, respectively. The results are : (1) In rate hike period, normally, the US stock market performed well. It's the time with economy booming at high growth rate and strong domestic demand that the Fed needs to take action, hiking rate, to cool down the market. (2) In the rate cut period, the US stock market was not good. That is because the rate cut decision is normally adopted due to slowing down economy, weak domestic demand, and stock market underperformance. Thus, the accumulated performance won't be too exciting during the rate cut period. (3) In the neutral period, the stock market performed excellently. Especially at the time after Fed's rate cut period, the stock market is booming due to the high liquidity and low interest rate environment, stimulating consumers spending and enterprises investment. (4) In the rate hike period, the oil price and commodity index (comprised by Reuters by averaging19 different commodity future index) were at the best performance. Besides, it also benefited the energy related share price. However, in the rate cut or neutral period, they were up and down without clear trend. (5) At the last, we further study the unexpected rate cut will surprise the market in upside. Given the results of these examinations, it is a good timing to buy when it's approaching the end of rate cut period. If the rate cut is unexpected or the extent is over expectation, investors shouldn't be too pessimistic. Instead, they should believe the government will continuously introduce favorable policy to boost the economy and it is good timing to invest in stock market.
32

Grass-fed cattle ranching in Texas : characteristics and motivations of ranchers

Riely, Andrew Carrington 03 September 2009 (has links)
Grass-fed cattle ranching is growing in popularity, but the characteristics and motivations of the ranchers, however, remain undefined. Based in Texas and using a mail survey and interviews with three grass-fed, three organic, and three conventional ranchers to identify some of their distinctive characteristics, this study achieved similar results to those comparing organic and conventional farmers. Grass-fed cattle ranchers tend to have high levels of education, approach ranching as a second career, and possess outside income sources. Motivated as much by ethics as economics, they embrace grass-fed methods primarily because they believe them to be healthiest for animals, humans, and the land. They eschew organic certification primarily because they perceive government regulations to be influenced by large conventional competitors, and they market their beef directly, often locally. Although many hope to expand their herd, most grass-fed cattle ranchers believe they are resisting “conventionalization” and say that they feel more self-sufficient and satisfied thanks to their choices. / text
33

The Effects of Direct-Fed Microbials on Performance and Digestive Tract Morphology of Neo-Natal/Transition Hostein Bull Calves

Dick, Karianne January 2006 (has links)
Calf diarrhea or scours is one of the most significant and costly problems dairy producers face on a daily basis. A study was designed and conducted to evaluate the effects of direct-fed microbials on the performance and digestive tract morphology of neo-natal/transition Holstein bull calves. Treatments consisted of a control (n = 21) and a treatment (n = 22) of direct-fed microbial (5 x 108 cfu) supplemented daily. Samples of the rumen, duodenum, and ileum were harvested at the time of slaughter and examined for differences in morphology. Although the direct-fed microbial did not effect performance, it positively effected the ruminal papillae as well as the ileal villi. These data indicate that direct-fed microbials may increase the nutrient absorptive surface area of the rumen and ileum, resulting in a healthier digestive tract.
34

Fault Ride-Through Capability of Doubly-Fed Induction Generators Based Wind Turbines

ABOBKR, ABOBKR 14 March 2013 (has links)
Due to growing concerns over climate change, more and more countries are looking to renewable energy sources to generate electricity. Therefore, wind turbines are increasing in popularity, along with doubly-fed induction machines (DFIGs) used in generation mode. Current grids codes require DFIGs to provide voltage support during a grid fault. The fault ride-through (FRT) capability of DFIGs is the focus of this thesis, in which modifications to the DFIG controller have been proposed to improve the FRT capability. The static synchronous compensator (STATCOM) controller has been applied with proposed method to study its influence on the voltage at the point of common coupling (PCC). The proposed method was also compared with other FRT capability improvement methods, including the conventional crowbar method. The simulation of the dynamic behaviour of DFIG-based wind turbines during grid fault is simulated using MATLAB/Simulink. The results obtained clearly demonstrate the efficacy of the proposed method.
35

Autumn field-feeding patterns of the wild mallard duck (Anas platyrhynchos)

Ball, Garth 31 September 1983 (has links)
Sixteen adult male and 8 adult female post moult mallards were equipped with radio transmitters, in a two year study (1977-6AHY-M and 4AHY-F; 1978-10AHY-M and 4AHY-F). Field-feeding was monitored at a lure crop and on adjacent grain fields. Ninety-two percent of the mallards radio-equipped were recorded at a field-feeding site at least once with 71% recorded field-feeding within one week. There was no significant difference in field-feeding activity between males and females. In the morning during periods of rain, mallards field-fed 0.55h longer, arriving 0.30h later and departing 0.9h later than mallards field-feeding during clear weather. The morning field-feeding period was longer in duration than the evening foeld-feeding period. Light intensity was the dominant climatological variable contributing to the arrival of mallards in the morning during periods of no rain (multiple R2=68.1%) and rain (R2=69.5%). Light appeared to act as an initiating cue for morning feeding activity. A high correlation existed between duration of stay during periods of no rain (r=0.815) and rain (r=0.860) suggesting that mallards remained longer at a field-feeding site in the morning by departing later, not arriving earlier. Light intensity was also the dominant climatological variable contributing to the arrival of mallards in the evening amongst those mallards which field-feed in both the morning and evening (R2=78.1%) and those which field-fed in the evening only (R2=63.3%). In addition, light intensity was the only contributing factor in the evening for all mallards departing a field-feeding site (R2=72.7%). Mallards were never recorded field-feeding longer than 15 minutes after there was non measurable light...
36

Controls on rhyolite lava dome eruptions in the Taupo Volcanic Zone

Ashwell, Paul January 2014 (has links)
The evolution of rhyolitic lava from effusion to cessation of activity is poorly understood. Recent lava dome eruptions at Unzen, Colima, Chaiten and Soufrière Hills have vastly increased our knowledge on the changes in behaviour of active domes. However, in ancient domes, little knowledge of the evolution of individual extrusion events exists. Instead, internal structures and facies variations can be used to assess the mechanisms of eruption. Rhyolitic magma rising in a conduit vesiculates and undergoes shear, such that lava erupting at the surface will be a mix of glass and sheared vesicles that form a permeable network, and with or without phenocryst or microlites. This foam will undergo compression from overburden in the shallow conduit and lava dome, forcing the vesicles to close and affecting the permeable network. High temperature, uniaxial compression experiments on crystal-rich and crystal-poor lavas have quantified the evolution of porosity and permeability in such environments. The deformation mechanisms involved in uniaxial deformation are viscous deformation and cracking. Crack production is controlled by strain rate and crystallinity, as strain is localised in crystals in crystal rich lavas. In crystal poor lavas, high strain rates result in long cracks that drastically increase permeability at low strain. Numerous and small cracks in crystal rich lavas allow the permeable network to remain open (although at a lower permeability than undeformed samples) while the porosity decreases. Flow bands result from shear movement within the conduit. Upon extrusion, these bands will become modified from movement of lava, and can therefore be used to reconstruct styles of eruption. Both Ngongotaha and Ruawahia domes, from Rotorua caldera and Okataina caldera complex (OCC) respectively, show complex flow banding that can be traced to elongated or aligned vents. The northernmost lobe at Ngongotaha exhibits a fan-like distribution of flow bands that are interpreted as resulting from an initial lava flow from a N – S trending fissure. This flow then transitioned into intrusion of obsidian sheets directly above the conduit, bound by wide breccia zones which show vertical movement of the sheets. Progressive intrusions then forced the sheets laterally, forming a sequence of sheets and breccia zones. At Ruawahia, the flow bands show two types of eruption; long flow lobes with ramp structures, and smaller spiny lobes which show vertical movement and possible spine extrusion. The difference is likely due to palaeotopography, as a large pyroclastic cone would have confined the small domes, while the flow lobes were unconfined and able to flow down slope. The vents at Ruawahia are aligned in a NE – SW orientation. Both domes are suggested to have formed from the intrusion of a dyke. The orientations of the alignment or elongation of vents at Ngongotaha and Ruawahia can be attributed to the overall regional structure of the Taupo Volcanic Zone (TVZ). At Ngongotaha, the N – S trending elongated vent is suggested to be controlled by a N – S trending caldera collapse structure at Rotorua caldera. The rest of the lobes at Ngongotaha, as well as other domes at Rotorua caldera, are controlled by the NE – SW trending extensional regional structure or a NW – SE trending basement structure. The collapse of Rotorua caldera, and geometry of the deformation margin, are related to the interplay of these structures. At Ruawahia, the NE – SW trending vent zone is parallel to the regional extension across the OCC, as shown by the orientation of intrusion of the 1886AD dyke through the Tarawera dome complex. The NE – SW trending regional structures observed at both Rotorua caldera and Okataina caldera complex are very similar to each other, but differ from extension within the Taupo rift to the south. Lava domes, such as Ngongotaha, that are controlled by this structure show that the ‘kink’ in the extension across Okataina caldera complex was active across Rotorua caldera during the collapse at 240 ka, and possibly earlier. This study shows the evolution of dyke-fed lava domes during eruption, and the control of regional structures in the location and timing of eruption. These findings improve our knowledge of the evolution of porosity and permeability in a compacting lava dome, as well as of the structures of Rotorua caldera, the longevity of volcanic activity at dormant calderas and the hazard potential of dyke-fed lava domes.
37

Autumn field-feeding patterns of the wild mallard duck (Anas platyrhynchos)

Ball, Garth 31 September 1983 (has links)
Sixteen adult male and 8 adult female post moult mallards were equipped with radio transmitters, in a two year study (1977-6AHY-M and 4AHY-F; 1978-10AHY-M and 4AHY-F). Field-feeding was monitored at a lure crop and on adjacent grain fields. Ninety-two percent of the mallards radio-equipped were recorded at a field-feeding site at least once with 71% recorded field-feeding within one week. There was no significant difference in field-feeding activity between males and females. In the morning during periods of rain, mallards field-fed 0.55h longer, arriving 0.30h later and departing 0.9h later than mallards field-feeding during clear weather. The morning field-feeding period was longer in duration than the evening foeld-feeding period. Light intensity was the dominant climatological variable contributing to the arrival of mallards in the morning during periods of no rain (multiple R2=68.1%) and rain (R2=69.5%). Light appeared to act as an initiating cue for morning feeding activity. A high correlation existed between duration of stay during periods of no rain (r=0.815) and rain (r=0.860) suggesting that mallards remained longer at a field-feeding site in the morning by departing later, not arriving earlier. Light intensity was also the dominant climatological variable contributing to the arrival of mallards in the evening amongst those mallards which field-feed in both the morning and evening (R2=78.1%) and those which field-fed in the evening only (R2=63.3%). In addition, light intensity was the only contributing factor in the evening for all mallards departing a field-feeding site (R2=72.7%). Mallards were never recorded field-feeding longer than 15 minutes after there was non measurable light...
38

ProduÃÃo de biomassa de Bacillus sp. RAB9 por fermentaÃÃo submersa. / BIOMASS PRODUCTION OF Bacillus sp. RAB9 BY SUBMERGED FERMENTATION

CÃvita Teixeira de Sousa 04 March 2013 (has links)
As bactÃrias promotoras de crescimento em plantas (BPCP) representam uma parcela funcional ativa da biota do solo sÃo presentes na rizosfera no rizoplano e no interior de plantas hospedeiras O uso biotecnolÃgico dessas bactÃrias tem se intensificado nos Ãltimos anos O gÃnero Bacillus vem sendo continuamente citado em estudos relacionados a promoÃÃo de crescimento em espÃcies vegetais Algumas espÃcies podem ser aplicadas no tratamento de sementes, ÃrgÃos de propagaÃÃo vegetativa e mudas Diante disso o presente trabalho teve como objetivo avaliar a produÃÃo de biomassa de Bacillus sp (RAB9) com potencial uso na promoÃÃo de crescimento de mudas de bananeira A cepa Bacillus sp (RAB9) pertencente ao grupo das bactÃrias epifÃticas, foi isolada de rabanete proveniente da ColeÃÃo de Culturas do LaboratÃrio de Fitobacteriologia da Universidade Federal Rural de Pernambuco Os experimentos foram realizados em agitador orbital e em reator de bancada Em agitador orbital foi estudada a curva de crescimento da linhagem a 30ÂC para observar sua fase exponencial Para a produÃÃo de biomassa foram observados os efeitos da adiÃÃo do teor de peptona (5 a 50 g.L-1) no meio NYD (extrato de carne, extrato de levedura peptona de carne e dextrose) adiÃÃo de elementos secundÃrios (K2HPO4 e MgSO4) e fonte de nitrogÃnio inorgÃnico ((NH4)2SO4) Em reator de bancada foram realizados testes com diferentes vazÃes de ar em batelada simples bem como uma comparaÃÃo com batelada alimentada com o meio modificado As fermentaÃÃes nos reatores apresentaram formaÃÃo de espuma testes foram feitos com Ãleos vegetais (milho canola girassol soja) e mineral para verificaÃÃo do melhor antiespumante Posteriormente aos testes foram quantificadas a biomassa o aÃÃcar residual nitrogÃnio residual e nitrogÃnio amoniacal Com os resultados obtidos foi observado a importÃncia da adiÃÃo dos elementos (MgSO4 e (NH4)2SO4) ao meio NYD e da vazÃo de ar sobre o crescimento da cepa Com os parÃmetros estudados foram determinadas as melhores condiÃÃes para a produÃÃo de Bacillus sp RAB9 / The growth-promoting bacteria in plants (BPCP) represents a functional portion of the active biota soil rhizosphere are present in rhizoplane and within host plants The biotechnological use of these bacteria has intensified in recent years The genus Bacillus has been continually cited in studies related to growth promotion in plant species Some species can be applied as a seed treatment organs for the vegetative propagation and seedling Therefore this study aimed to assess the biomass of Bacillus sp (RAB9) with potential use in promoting growth of banana plantlets The strain Bacillus sp (RAB9) belonging to the group of epiphytic bacteria was isolated from radish from the Culture Collection of the Laboratory of Fitobacteriologia Federal Rural University of Pernambuco The experiments were performed on an orbital shaker and batch reactor In orbital shaker was studied growth curve of strain at 30ÂC to observe their exponential phase For the production of biomass were observed the effects of adding the content of peptone (5 to 50 g.L-1) in NYD medium (meat extract yeast extract meat peptone and dextrose) addition of secondary elements (K2HPO4 and MgSO4) and inorganic nitrogen source ((NH4)2SO4) In batch reactor tests were conducted with different air flows in simple batch and fed batch with a comparison with the modified medium The fermentations presented in the reactors foaming tests were made with vegetable oils (corn canola sunflower soybean) and to verify the best mineral defoamer Later tests were quantified biomass residual sugar residual nitrogen and ammonia nitrogen With the results noted the importance of the addition of elements (MgSO4 and (NH4)2SO4) in half NYD and air flow on the growth of strain With the studied parameters were determined the best conditions for the production of Bacillus sp RAB9
39

Estudo fenomenologico do reator batelada alimentada utilizando dois processos fermentativos distintos / Phenomenological study of the fed-batch reactor using two distinct fermentation processes

Gonzales, Tatiane Araujo 03 August 2018 (has links)
Orientador: Ranulfo Monte Alegre / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T21:39:56Z (GMT). No. of bitstreams: 1 Gonzales_TatianeAraujo_M.pdf: 808675 bytes, checksum: 754d8f090b92f6186edb2bc0bad0c5b2 (MD5) Previous issue date: 2004 / Resumo: O processo de batelada alimentada é útil para o estudo da cinética de processos fermentativos, pois permite a manutenção de baixos níveis de substrato por longo período de tempo, que é favorável à estimativa de parâmetros cinéticos; permite manter concentração celular constante e controlar a velocidade de crescimento em condições transientes. São as equações cinéticas que indicam como as variáveis de estado do processo em estudo interferem nas velocidades de crescimento e morte celular, de geração de produtos metabólicos e de consumo de substrato. Estudos de biorreatores de batelada alimentada têm sido freqüentemente relatados na literatura, entretanto para a modelagem destes processos necessita-se conhecer parâmetros cinéticos e informações sobre estes são escassas. A implantação do PROÁLCOOL no Brasil fez aumentar o número de destilarias. Atualmente, o processo de batelada alimentada responde por cerca de 60% do volume de etanol produzido. Outro processo fermentativo de alto valor comercial é a produção de ácido lático, uma vez que este tem grande aplicação no uso em alimentos, na área farmacêutica, de plásticos e indústria química. Desta forma, o objetivo deste trabalho foi estudar duas fermentações distintas com relação à cinética de produção e entender a fenomenologia do processo de batelada alimentada. Escolheram-se dois tipos de fermentações com cinética de produção diferentes, uma alcoólica e outra lática, o primeiro com produção associada ao crescimento e o outro de produção parcialmente associada ao crescimento. Realizaram-se ensaios de fermentações em batelada para obtenção dos parâmetros cinéticos e em batelada alimentada para aplicação dos parâmetros obtidos em modelos e estes em balanço de massa do processo batelada alimentada. Em seguida, foram conduzidas simulações do processo batelada alimentada com o auxílio do software AnaBio 1.0 e ajustados os parâmetros cinéticos através de análise visual, utilizando-se dois modelos encontrados na literatura: o modelo cinético de Monod e outro também baseado em Monod com inclusão de um termo de inibição pelo produto. Estes modelos representaram visualmente os dados experimentais de forma satisfatória para a fermentação alcoólica, no entanto, somente um ajuste regular dos dados experimentais em relação aos preditos foram obtidos para fermentação lática / Abstract: The fed-batch process is useful for studying of fermentation process kinetic, because it allows keeping low level of substrate for a long period, which is favorable to estimate kinetic parameters; it enables keeping a constant biomass concentration and controlling growing rate in transient conditions. The kinetic equations indicate how the process variables interfere in the cell growing rate and death, the metabolic product formation and substrate consumption. The bioreactors studies of fed-batch have been often found on specialized literature, however, its necessary to know the kinetic parameters that are not available. A very important program in Brazil, called PROALCOOL, leveraged a raise in the number of alcohol industries and 60% of ethanol assembled in this country, in the present time, use fed-batch process. Another interesting process is the production of lactic acid, which is important to food, pharmaceutical, plastic and chemical industry. Therefore the main objective of this project was to study two different fermentation processes to apply the material balance of the fed-batch reactor with determined parameters and known mathematical models. Two production kinetic fermentations were chosen, one alcoholic and another lactic. The first one is associated with the cell growth and the other is partially associated with cell growth. Some batch fermentations essays were carried out to obtain kinetics parameters and fed-batch processes were performed to study the kinetic process. Simulations of fed-batch process, running the software Anabio 1.0, were executed and the kinetic parameters fitted through visual analysis, using two known models, Monod kinetic model and Monod including inhibitory effect of product. Theses models were better visually represented by the alcoholic fermentation experimental data than lactic fermentation data. In the condition of the fed-batch assays the Monod or Monod with inhibitory effect of product inserted in the material balance do not describe these process / Mestrado / Mestre em Engenharia de Alimentos
40

A Comparison of the Unconventional Monetary Policies of the ECB and the FED / Porovnání nekonvenční měnové politiky ECB a FED

Bohůnek, Matěj January 2016 (has links)
The monetary policy of the Fed and the ECB has greatly change as a result of the global crisis. The goal of the thesis is to analyse the evolution of unconventional monetary instruments in the USA and the EU after the outbreak of the global crisis and nowadays with the help of pivotal economic models; namely, the IS-LM-BP model and the quantity theory of money. In addition, the paper should assess the impacts of adopted instruments and programs and draw conclusions about their success. The theoretical part explains the IS-LM-BP framework and the quantity theory of money and describes the unconventional monetary tools that the central banks can use when the interest rates reach the zero lower bound. The practical part analyses EU and US economy with the explained models. Furthermore, the implemented instruments of the Fed and the ECB are described and compared. The thesis should be concluded with the claim that the transmission mechanism was restored with the help of the non-standard measures, however, the desirable price level stabilization has not been reached.

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