The aim of my thesis was to monitor the natural occurrence of mycological pathogens, especially funghi of genus Fusarium in ecologically and conventionally grown systems. There was carried out small-parcelled experiments at two standpoints (Lukavec and České Budějovice) in the years 2006/2007, 2007/2008 and 2008/2009. The funghi of genus Fisarium attack the stalk, the leaves even the ear. If the ear is attacked, the production is decreased. The epidemical occurrence of this disease is supported by a large amount of cereals in the cropping pattern, nitrogen over-fertilization, thick grassland and bad agro technological proceeding, especially imperfectly nested plant remains. The genus Fisarium is very extensive in the nature. It often parasites at plants or live saprophyticly at production, post-production remains of plants in soil or at its surface. The mycelium furcates and forms cottonwoolen pinkish, red or yellowish film. Their malignity lies with the production of poisonous mycotoxins, which form as their secondary metabolites. They can cause the health problems at people and farm animals.

Com o objetivo de avaliar os efeitos das faixas de controle das plantas daninhas sobre o crescimento do eucalipto foram conduzidos dois ensaios localizados nos municípios de Três Lagoas, MS (julho de 1996 a agosto de 2000) e de Brotas, SP (fevereiro de 1997 a março de 2001). Os tratamentos experimentais destes ensaios constaram de dois grupos: (i) grupo I: faixas fixas de controle durante os 12 meses iniciais, a: 0, 25, 50, 100, 125 e 150 cm de cada lado da linha de plantio do eucalipto; e, (ii) grupo II faixas crescentes de controle, a: 25 a 150, 25-50-150, 50-125-150, 100-125-150, 100 a 150 e 125 a 150 cm. Aos 49 meses após o plantio dessas áreas, foi constatado que as plantas de eucalipto que cresceram nas parcelas com faixas de controle fixas iguais a 100 cm ou crescentes superiores a 50 cm nos três primeiros meses, respectivamente, mostraram-se superiores, em diâmetro medido à altura do peito (D.A.P.), altura, volume e incremento médio anual de madeira (I.M.A.). Já com o objetivo de estudar os efeitos dos períodos de controle das plantas daninhas sobre a produtividade do eucalipto foram conduzidos três ensaios localizados nos municípios de Três Lagoas, MS (janeiro de 1997 a março de 2001), Brotas, SP (fevereiro de 1997 a fevereiro de 2001) e Piratininga, SP (agosto de 1991 a maio de 1999). Nos ensaios de Três Lagoas, MS e Brotas, SP, os tratamentos consistiram de diferentes períodos de convivência e de controle das plantas daninhas na cultura divididos em dois grupos. No primeiro, a convivência iniciava no plantio e estendia até 28, 56, 84, 112, 140, 168, 252 e 364 dias. No segundo, a convivência iniciava aos 0, 28, 56, 84, 112, 140, 168 e 252 dias e estendia até os 364 dias. Para Três Lagoas, MS, o período total de prevenção à interferência (PTPI) foi de 180 e 210 dias, quando se considera a redução de 5 e 2% no volume de madeira aos 50 meses após o plantio, respectivamente. No entanto, para Brotas, SP, o PTPI foi de 60 dias, considerando-se 5% de redução em volume de madeira aos 24 meses após o plantio. Todavia, pode-se questionar o efeito da interferência das plantas daninhas distribuídas irregularmente na área de Brotas, SP e sugerir a hipótese de recuperação das plantas de eucalipto a partir de 48 meses, bem como o potencial alelopático dos restos culturais do eucalipto. Em Piratininga, SP, os tratamentos consistiram de diferentes períodos de convivência e de controle das plantas daninhas na cultura do eucalipto divididos em dois grupos. No primeiro, a convivência iniciava no plantio e era estendida até 28, 56, 84, 112, 140, 168, 278 e 360 dias. No segundo, a convivência iniciava aos 0, 28, 56, 84, 112, 140, 168 e 278 dias e era estendida até 364 dias. O PTPI foi de 79 dias quando se analisa o volume de madeira (m 3 .ha -1 ) aos 78 meses após o plantio (colheita da cultura). / This research has been carried out in areas of Eucalyptus sp in Três Lagoas, Mato Grosso do Sul State, Brazil (from July 1996 through August 2001) and Brotas, São Paulo State, Brazil (from February 1997 through March 2001), to evaluate the effects of weed control strip variations at the Eucalyptus growth. The experiments consisted of two treatments: group 1 – with constant width control strips have been kept throughout the first 12 months, i.e., at 0, 25, 50, 100, 125 and 150 cm on both sides of the Eucalyptus row and, group 2: with an increasing of the width control strips has been adopted along the experimental period, i.e., at 25 to 150, 25-50-150, 50 at 150, 50-125-150, 100-125-150, 100 to 150 and 125 to 150 cm on both sides of the Eucalyptus row. After 49 months that areas were planted it was checked that the Eucalyptus plants that had grown as in the constant and as in increasing width control strips, equal to or higher than 100 and 50 cm, respectively has showed a higher diameter, height plant, volume and annual average increment of the wood. These results have led to the conclusion that the control minimum strip width should be 100 cm on the both sides of the Eucalyptus row in order to keep it the weed interference. This research has been carried out in Três Lagoas, Mato Grosso do Sul State, Brazil (from January 1997 through March 2001) and Brotas, São Paulo State, Brazil (from February 1997 through 2001) and Piratininga, São Paulo State, Brazil (from August 1991 through May 1999), with the purpose study of a studying about the effects of the weed interference at the Eucalyptus sp growth. In Três Lagoas and in Brotas the treatments have consisted of in the different extensions and the different time limits of the weed control periods. The weed control periods have been divided in to two groups. At the first one, the weed control periods have been since the Eucalyptus plantation to 28, 56, 112, 140, 168, 224, 252 and 364 days. At the second group, the weed control period has begun at 0, 28, 56, 112, 140, 168, 224 and 252 days after the plantation and has finished at the end of the 364 days. To assure the crop productivity in Três Lagoas it was necessary to keep a weed control period in a range of 180 and 210 days after plantation, in that case it should consider a reduction of 5% at the wood volume in the 50 months after the plantation. However, in Brotas area it was necessary to keep the weed control plantation in a range of 60 days of to consider the wood volume throughout 24 months after the plantation. However, it might ask about question the effects of the weed interference in a case of a low density and in a weed irregular distribution in that area, suggesting improvement at the quality of the Eucalyptus plants in a range of 48 months after the plantation the allelophatic potential from the Eucalyptus mulching as well. In Piratininga the treatments have consisted of different extensions and time limits of the weed control periods. The weed control periods has been since the Eucalyptus plantation to 28, 56, 112, 140, 168, 224, 278 and 360 days. At the second group the weed control period has begun in a range of 0, 28, 56, 112, 140, 168, 224 throughout 278 days after the plantation and has finished at the end of the 364 days. It has been necessary to keep a weed control period in a range of 79 days after the plantation throughout 78 months, in that case it should consider reduction of 5% at the wood volume.

[pt] O debate em torno da relação entre câmbio real e crescimento, apesar de antigo no meio acadêmico, se fortaleceu com as experiências de alguns países asiáticos de rápido crescimento econômico e manutenção da taxa de câmbio real em níveis muito baixos. Estudos recentes documentam que desvalorizações cambiais até certo nível podem ter efeito positivo sobre o crescimento, enquanto que sobrevalorizações são sempre negativas. O objetivo desta dissertação é mostrar que existe uma relação direta entre poupança doméstica e câmbio real, e entre poupança e crescimento, de forma que os resultados mencionados acima falham ao não levar em consideração a dinâmica conjunta destas três variáveis. Para isso, mostramos, primeiramente, evidência teórica de que países com maiores taxas de poupança, ao mesmo tempo em que apresentam câmbio real mais desvalorizado, também são aqueles que apresentam maiores taxas de crescimento da produtividade. Adicionalmente, realizamos uma análise empírica para 80 países durante o período de 1970 a 2004, onde calculamos o câmbio de equilíbrio incluindo a taxa de poupança como um de seus fundamentos, e em seguida, estimamos a correlação dos desvios do câmbio com relação ao nível de equilíbrio (calculado na etapa anterior) com o crescimento. A análise das regressões mostra que os desvios cambiais, ao levarem em consideração o efeito da poupança sobre o câmbio de equilíbrio, não parecem ser correlacionados com o crescimento econômico. Ao passo que, políticas de estímulo à poupança doméstica, ao mesmo tempo em que influenciam o câmbio de equilíbrio, também parecem promover maior crescimento econômico. / [en] The debate about the relation between real exchange rates and economic growth, even though old in the academics circle, grew strongly with the Asian experience of fast economic growth and the maintenance of low levels of real exchange rates. Recently, studies have shown that undervaluation of the real exchange rate until some level could have positive impact on growth, while overvaluations are thought to (always) have negative relation with economic performance. We will argue in this work that these results fail to take into consideration the dynamics of a third variable: the country`s savings rate. First we show theoretical evidence that countries with higher savings rate will have a more devalued real exchange rate and at the same time, will show higher productivity growth rates. Secondly, we present an empirical analysis of 80 countries during the period from 1970 to 2004, were we calculate the equilibrium real exchange rate including the savings rate as one of its fundamentals, and after that, we estimate the relation between the real exchange rate deviation from its equilibrium level and economic growth. The regression analysis shows us that the real exchange rate misalignment is not correlated at all with a country`s economic performance. We conclude that policies that stimulate the savings decision are much more important for growth than the deviations of the exchange rate that does not reflect the economy`s fundamentals.

Application of fertilizers to soils to increase production yields has raised questions concerning the effect of fertilizer on chemical composition of plants. With the development of accurate, sensitive microbiological methods for the determination of amino acid in protein, speculations concerning amino acid content have been supplanted by acquisition of facts.

A data analytic materials informatics methodology is proposed after applying different data mining techniques on some datasets of particular domain in order to discover and model certain patterns, trends and behavior related to that domain. In essence, it is proposed to develop an information mining tool for vapor-grown carbon nanofiber (VGCNF)/vinyl ester (VE) nanocomposites as a case study. Formulation and processing factors (VGCNF type, use of a dispersing agent, mixing method, and VGCNF weight fraction) and testing temperature were utilized as inputs and the storage modulus, loss modulus, and tan delta were selected as outputs or responses. The data mining and knowledge discovery algorithms and techniques included self-organizing maps (SOMs) and clustering techniques. SOMs demonstrated that temperature had the most significant effect on the output responses followed by VGCNF weight fraction. A clustering technique, i.e., fuzzy C-means (FCM) algorithm, was also applied to discover certain patterns in nanocomposite behavior after using principal component analysis (PCA) as a dimensionality reduction technique. Particularly, these techniques were able to separate the nanocomposite specimens into different clusters based on temperature and tan delta features as well as to place the neat VE specimens in separate clusters. In addition, an artificial neural network (ANN) model was used to explore the VGCNF/VE dataset. The ANN was able to predict/model the VGCNF/VE responses with minimal mean square error (MSE) using the resubstitution and 3olds cross validation (CV) techniques. Furthermore, the proposed methodology was employed to acquire new information and mechanical and physical patterns and trends about not only viscoelastic VGCNF/VE nanocomposites, but also about flexural and impact strengths properties for VGCNF/ VE nanocomposites. Formulation and processing factors (curing environment, use or absence of dispersing agent, mixing method, VGCNF fiber loading, VGCNF type, high shear mixing time, sonication time) and testing temperature were utilized as inputs and the true ultimate strength, true yield strength, engineering elastic modulus, engineering ultimate strength, flexural modulus, flexural strength, storage modulus, loss modulus, and tan delta were selected as outputs. This work highlights the significance and utility of data mining and knowledge discovery techniques in the context of materials informatics.

The use of nanoreinforcements in automotive structural composites has provided promising improvements in their mechanical properties. For the first time, a robust statistical design of experiments approach was undertaken to demonstrate how key formulation and processing factors (nanofiber type, use of dispersing agent, mixing method, nanofiber weight fraction, and temperature) affected the dynamic mechanical properties of vapor-grown carbon nanofiber (VGCNF)/vinyl ester (VE) nanocomposites. Statistical response surface models were developed to predict nanocomposite storage and loss moduli as functions of significant factors. Only ~0.50 parts of nanofiber per hundred parts resin produced a roughly 20% increase in the storage modulus versus that of the neat VE at room temperature. Optimized nanocomposite properties were predicted as a function of design factors employing this methodology. For example, the use of highshear mixing (one of the mixing methods in the design) with the oxidized VGCNFs in the absence of dispersing agent or arbitrarily with pristine VGCNFs in the presence of dispersing agent was found to maximize the predicted storage modulus over the entire temperature range (30-120 °C). To study the key concept of interphase in thermoset nanocomposites, molecular dynamics simulations were performed to investigate liquid VE resin monomer interactions with the surface of a pristine VGCNF. A liquid resin having a mole ratio of styrene to bisphenol A-diglycidyl dimethacrylate monomers consistent with a 33 wt% styrene VE resin was placed in contact with both sides of pristine graphene sheets, overlapped like shingles, to represent the outer surface of a pristine VGCNF. The relative monomer concentrations were calculated in a direction progressively away from the surface of the graphene sheets. At equilibrium, the styrene/VE monomer ratio was higher in a 5 Å thick region adjacent to the nanofiber surface than in the remaining liquid volume. The elevated styrene concentration near the nanofiber surface suggests that a styrene-rich interphase region, with a lower crosslink density than the bulk matrix, could be formed upon curing. Furthermore, styrene accumulation in the immediate vicinity of the nanofiber surface might, after curing, improve the nanofiber-matrix interfacial adhesion compared to the case where the monomers were uniformly distributed throughout the matrix.

Pyrograf IIITM,/sup> fibers (PR-19-PS, Applied Sciences, Inc.) with 100-300 nm diameters and ~ 10-100 ìm lengths were used with a low viscosity aliphatic epoxy resin (Clearstream 9000, Clearstream Products, Inc.) to produce composites. The VGCFs were oxidized in 69-71 wt% nitric acid (115°C) for various times (10 min to 24 h) to modify the surface to enhance fiber/matrix adhesion. Remarkably, little fiber weight loss was detected even after 24 h of oxidation. Composites containing 19.2 volume percent (29.4 weight percent) VGCFs were prepared. Their flexural strengths and flexural moduli were obtained. The flexural strengths did not increase using oxidized VGCFs. Fiber surfaces were characterized using N2 BET, CO2 DR, XPS, SEM, TEM and base uptake measurements. Increasing the oxidation time produced only small initial increases in surface area up to a limit. Significant surface oxygen was present before oxidation and the amount increased initially, though not continuously, with nitric acid oxidation.

The effects of material/fabrication parameters on vapor-grown carbon nanofiber (VGCNF) reinforced vinyl ester (VE) nanocomposite flexural moduli and strengths were investigated. Statistically reliable empirical response surface models were developed to quantify the effects of VGCNF type, use of dispersing agent, mixing method, and VGCNF loading on flexural properties. Optimal nanocomposite formulation and processing (0.74 phr oxidized VGCNFs, dispersing agent, and high-shear mixing) resulted in predicted flexural modulus and strength values 1.18 and 1.26 times those of the neat resin. Additional flexural, tensile, and compressive tests were performed for optimally configured nanocomposites cured in a nitrogen environment. While flexural and tensile moduli significantly increased with increasing VGCNF loading, the corresponding strengths fell below those of the neat resin. In contrast, nanocomposite ultimate compressive strengths significantly exceeded the neat resin strengths. Nanocomposites prepared using aggressive high-shear mixing displayed improved elastic moduli and substantially increased strengths relative to nanocomposites prepared using baseline methods.

No description available.

No description available.