Made available in DSpace on 2014-06-12T23:01:58Z (GMT). No. of bitstreams: 2 arquivo8578_1.pdf: 728986 bytes, checksum: fa36aba72be687d143a24c7a98efae09 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006 / Apesar da facilidade de cultivo, a produção de hortaliças é inviabilizada economicamente pela perecibilidade que causa perdas provocadas principalmente pelas condições inadequadas de conservação. A vida útil das hortaliças é beneficiada pela conservação em temperatura em torno de 10oC. Em climas quentes e secos, como no semi-árido nordestino, esta condição é possível mediante equipamentos de refrigeração que demandam custos e energia elétrica, condição esta incompatível com as das populações de baixa renda. O sistema Pot in Pot desenvolvido na Nigéria, consiste na superposição de dois potes de cerâmica de diferentes tamanhos dispostos um dentro do outro e de uma camada de areia molhada inserida entre eles que proporciona o resfriamento do pote interno pela evaporação da água, conseguindo-se aumentar o tempo de vida útil de vegetais. Com o objetivo de avaliar o efeito deste sistema de conservação sobre hortaliças produzidas no Nordeste brasileiro foi desenvolvida esta pesquisa comparando o sistema Pot in Pot (27±0,40C e 83±0,6%UR) com o ambiente de uma câmara climatizada para a condição semelhante a do semi-árido nordestino (37±0,7ºC e 40±0,5%UR) e com outro sistema convencional de conservação: refrigeração em geladeira doméstica (7±0,30C e 53±1%UR), utilizando-se amostras sem embalagem e amostras embaladas em polietileno de alta densidade. Dois tipos de hortaliças foram utilizados: pimentão e tomate, adquiridos no comércio atacadista. Os experimentos foram realizados em 3 repetições e em cada utilizando-se 72 unidades de tomate e 80 de pimentão. Todas as amostras foram selecionadas, limpas, identificadas, pesadas e fotografadas. Em seguida foi retirada uma unidade de cada amostra para ensaios laboratoriais de pH, sólidos solúveis totais (SST), acidez total titulável (ATT) e textura, correspondendo ao tempo zero do experimento. As demais amostras foram divididas em 2 porções iguais onde uma delas foi submetida a sanitizacão. Em seguida, todas as amostras sanitizadas ou não, foram armazenadas nos 3 diferentes ambientes. A cada 7 dias, as amostras foram analisadas quanto às características visuais (cor, brilho, frescor, turgência e enrugamento), perdas de peso, pH, acidez total titulável, sólidos solúveis totais e textura até apresentarem sinais de alteração que as tornaram impróprias para o consumo. Nas análises físico-químicas utilisou-se métodos preconizados por AOAC. Os resultados demonstraram diferenças significativas (p<0,05) entre os ambientes e os períodos de armazenamento. Concluiu-se que: o uso do sistema Pot in Pot proporcionou aumento da vida útil das hortaliças estudadas e foi o mais eficiente para a conservação do tomate; a refrigeração com embalagem foi o melhor ambiente para o pimentão; as características visuais e o aparecimento de fungos foram limitantes na vida útil de pimentão e a turgescência para a conservação de tomate; a sanitização com cloro não contribuiu para a conservação das hortaliças; o aparecimento de fungos em todos os sistemas utilizados aponta para a necessidade da associação de fungicida específico e que a eficiência do sistema Pot in Pot é dependente das características intrínsecas das hortaliças

A more thorough knowledge of rooting behavior of transplanted trees is needed to better understand plant establishment. The objectives of this research were to: 1) determine if transplant timing affected root system regeneration of northern red oak (Quercus rubra L.) and willow oak (Q. phellos L.), 2) determine the effect of transplant timing and nursery production system on root, shoot, and trunk growth periodicity of balled-and-burlapped (B&B) and pot-in-pot (PIP) sugar maple (Acer saccharum Marsh.), and 3) characterize seasonal patterns of root production and mortality of transplanted sugar maple. No new root growth occurred outside or within the root balls of red or willow oak between November transplanting and January excavation. However, new root growth was observed when November- and March-transplanted oaks were excavated in April, indicating that new root growth occurs primarily in late winter and/or early. Transplanted and non-transplanted sugar maples exhibited a pattern of maximum rates of shoot extension in early May, root length accumulation in late May, and trunk expansion in mid June. Rate of root length accumulation was less in summer and fall. Transplanting did not appear to disrupt the normal growth periodicity of sugar maple, except when transplanted in July. Abundant root length accumulation occurred in the July transplants at a time when root length accumulation had slowed in all other treatments, resulting in the July transplants having similar standing root lengths as the other transplants by fall. Standing root length of non-transplanted PIP sugar maple declined dramatically in spring. While root production in sugar maple was limited to the growing season, root mortality occurred at a steadier rate throughout the year. Most root mortality occurred in winter in transplanted trees and spring and summer in non-transplanted trees. Non-transplanted PIP trees had greater standing root length, production, and mortality than the other treatments. Indices of root activity (analogous to turnover rates) and production:mortality ratios illustrated the dominant role that root production plays relative to mortality in recently transplanted trees. These data indicate that transplanting and the PIP production system disrupt typical patterns of root production and mortality in sugar maple. / Ph. D.

No description available.

In this report a novel low temperature synthesis approach of CdS nanocrystals is described starting from well known precursors, Cd(SA) and TOP-S, in a ligand system of aliphatic long chain alcohols. A one-pot synthesis approach is applied using a laboratory microwave heating source. The resulting CdS nanocrystals exhibit an absorbance with a pronounced fine-structure, a photoluminescence with a very high ratio between the band gap peak and the defect peak and a fluorescence quantum yield of 33%. Different synthesis approaches have been investigated by changing heating rate, temperature, precursor concentration and chain length of the aliphatic alcohol ligand as well as chain length of the Cadmium precursor. It was found that small changes in the heating rate do not affect the reaction. Changing the reaction temperature between 200°C and 160°C has no visible effects on the quality of the resulting CdS nanocrystals. At 140°C the nanoparticles experience a significant drop in quality, probably because there is a major change in the growth mechanism of the nanocrystals at that low temperature. At 100°C and 120°C the creation of so-called CdS nanoclusters is observed, and a growth mechanism towards nanocrystals based on cluster aggregation is suggested. For the synthesis of high quality nanoparticles it was found that a ratio of 1:25 between precursor and aliphatic alcohol is preferable as well as a ratio of 1:1 between the two precursors. If the chain length of both the precursors and the alcohol is short, the reaction rate is enhanced. If the chain length is too short the nanocrystals grow very fast and the size distribution gets broad, the photoluminescence intensity decreases and the ratio between band gap luminescence and defect luminescence decreases. The best Cd-precursor was found to be Cd-Laurate and the most suitable ligand evaluated was Tetradecanol.

The first section of this dissertation (Chapter I-III) describes the development of new methodologies to prepare uracil and arylidenehydantoin derivatives. A regioselective synthesis of 6-alkyl- and 6-aryluracils was developed by the dimerization of 3-alkyl- and 3-aryl-2-propynamides promoted by either Cs2CO3 or K3PO4. A range of 3-aryl-2- propynamides, with both electron-deficient and electron-rich 3-aryl substituents, were successfully reacted in high yields. A synthetic route to prepare arylidenehydantoins was developed using the Pd-catalyzed dimerization of 3-aryl-2-propynamides. Both electron rich and electron deficient 3-aryl-2-propynamides were dimerized successfully to produce the desired arylidenehydantoins in moderate to excellent yields. The second section of this dissertation (Chapter IV and V) describes the development of a reliable low-cost method to determine amounts of xylitol in sugar free gum samples to predict dangerous exposure levels for dogs. Xylitol is generally considered safe for human consumption and is frequently used in sugar free gum, however, it is extremely toxic to dogs. It is unknown if partially consumed chewing gum is also dangerous. A method to determine xylitol content of these sugar free gum samples employing GC-MS with direct aqueous injection (DAI) is presented. This method was successfully applied to over 120 samples including, fresh gum, 5 min, 15 min, and 30 min chewed gum samples. Further extension of this work resulted in the development of an undergraduate laboratory experiment for upper-level undergraduate chemistry students which teaches calibration methods, xylitol extraction, sample preparation for GC-MS analysis, and data analysis.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-15T20:05:31Z No. of bitstreams: 1 DenisKeutonAlves_DISSERT.pdf: 1354473 bytes, checksum: 0f20fcd2caa18ee04e30be7d88ad506e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-19T22:47:31Z (GMT) No. of bitstreams: 1 DenisKeutonAlves_DISSERT.pdf: 1354473 bytes, checksum: 0f20fcd2caa18ee04e30be7d88ad506e (MD5) / Made available in DSpace on 2016-04-19T22:47:31Z (GMT). No. of bitstreams: 1 DenisKeutonAlves_DISSERT.pdf: 1354473 bytes, checksum: 0f20fcd2caa18ee04e30be7d88ad506e (MD5) Previous issue date: 2015-06-19 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / A monitora??o das grandezas el?tricas em sistemas el?tricos de pot?ncia tem como objetivo promover a confiabilidade, bem como a qualidade da energia el?trica distribu?da. Diante disso, prop?e-se nessa disserta??o um estudo sobre uma nova teoria de pot?ncia baseada na transformada wavelet para estima??o em tempo real dos valores RMS da tens?o e corrente e alguns valores de pot?ncias, tais como: pot?ncia ativa, pot?ncia reativa, pot?ncia aparente e fator de pot?ncia. A estima??o adequada dos valores RMS e das pot?ncias s?o importante para diversas aplica??es, como por exemplo: projetos e an?lise de sistemas de energia, dispositivos de compensa??o para melhorar a qualidade da energia el?trica e instrumentos de medi??o de energia. Os resultados de simula??o e experimentais obtidos pelo m?todo proposto baseado na transformada wavelet discreta redundanteforam comparados por meio do padr?o IEEE 1459-2010 e por um oscilosc?pio comercial, respectivamente, apresentando resultados equivalentes. O m?todo proposto apresentou bom desempenho para wavelets m?es curtas, o que torna vi?vel para aplica??es em tempo real. / The goal of the power monitoring in electrical power systems is to promote the reliablility as well as the quality of electrical power.Therefore, this dissertation proposes a new theory of power based on wavelet transform for real-time estimation of RMS voltages and currents, and some power amounts, such as active power, reactive power, apparent power, and power factor. The appropriate estimation the of RMS and power values is important for many applications, such as: design and analysis of power systems, compensation devices for improving power quality, and instruments for energy measuring. Simulation and experimental results obtained through the proposed MaximalOverlap Discrete Wavelet Transform-based method were compared with the IEEE Standard 1459-2010 and the commercial oscilloscope, respectively, presenting equivalent results. The proposed method presented good performance for compact mother wavelet, which is in accordance with real-time applications.

La méthodologie MAC consiste à employer des réactifs umpolung pour permettre l’insertion formelle d’une fonction carbonyle entre un électrophile et un nucléophile. Cette thèse est consacrée à l’oxyhomologation diastéréosélective de la L-sérine grâce à un développement significatif de la méthodologie MAC à trois composants en one-pot, conduisant à l’obtention de dérivés orthogonalement protégés de l’acide α, γ-dihydroxy-β-aminobutyrique. Ce dernier est une brique moléculaire acyclique à 4 atomes de carbone hautement fonctionnalisée qui est souvent intégrée dans les squelettes de molécules biologiquement actives.Nous avons tout d’abord étudié la synthèse de réactifs MAC silylés à partir du malononitrile. La synthèse du H-MAC-TBS a été optimisée et deux nouveaux réactifs MAC silylés, le H-MAC-TES et le H-MAC-TBDPS, ont été préparés.Dans un premier temps, nous avons étudié l’oxyhomologation du N-Boc-O-Bn-L-sérinal avec le H-MAC-TBS en présence de différents alcools dans des conditions réactionnelles douces. En présence de méthanol, des α, γ-dihydroxy-β-aminobutanoates de méthyle orthogonalement protégés ont été préparés avec des bons rendements et avec un ratio diastéréoisomérique syn/anti = 80/20.L’utilisation du H-MAC-TBDPS a permis d’améliorer la diastéréosélectivité de la réaction MAC (syn/anti = 90/10). L’étude des différents modes de cyclisation des α, γ-dihydroxy-β-aminobutanoates de méthyle a été réalisée par la suite. Des hétérocycles fonctionnalisés à 3, 5 et 6 chaînons ont été ainsi sélectivement synthétisés.De nouvelles oxazolidinones et oxazolines hautement fonctionnalisées ont été préparées de cette façon. En revanche, malgré nos efforts approfondis, une cyclisation pour donner un hétérocycle à 4 chaînons n’a pas été réalisée.L’absence de réactivité de la fonction alcool libre en α de ces esters N-protégés et γ activés a été inattendue.Dans un deuxième temps, nous avons étudié l’oxyhomologation de l’aldéhyde de Garner, un dérivé cyclique N,O-protégé du L-sérinal, par des réactions MAC. En présence de divers nucléophiles, cette réaction a conduit diastéréosélectivement à des esters et des amides protégés de l’acide α, γ-dihydroxy-β-aminobutyrique avec des bons rendements et avec une diastéréoselectivité anti, allant jusqu’à un ratio diastéréoisomérique syn/anti = 10/90 en utilisant le H-MAC-TBDPS. Il s’agit des premiers exemples de diastéréosélectivité antiobservée pour une réaction MAC. Des hétérocycles fonctionnalisés à 3 et 5 chaînons ont été sélectivement synthétisés et, grâce à une oxydation sélective en position γ, des dérivés de l’acide érythro-β-hydroxyaspartique et de l’érythro-β-hydroxyasparagine orthogonalement protégés ont été préparés. / MAC methodology is a synthetic technique which employs an umpolung reagent to formally insert a carbonyl function between an electrophile and a nucleophile. This thesis is devoted to the diastereoselective oxyhomologation of L-serine thanks to a significant development of 3-component one pot MAC methodology, providing a synthesis of orthogonally-protected derivatives of α, γ-dihydroxy-β-aminobutyric acid. This latter is a highly functionalized, acyclic, 4-carbon molecular building block which is a constituent part of various biologically active molecules.The synthesis of silylated MAC reagents from malononitrile was first studied. H-MAC-TBS’s synthesis was optimized and two new silylated MAC reagents, H-MAC-TES and H-MACTBDPS,were prepared.In a first study, the oxyhomologation of N-Boc-O-Bn-L-serinal was examined using H-MACTBS and a panel of alcohols in mild conditions.Methyl esters of orthogonally-protected α, γ-dihydroxy-β-aminobutanoic acid were prepared in good yields and with a diastereoisomeric ratio syn/anti = 80/20. The use of H-MAC-TBDPS improved the diastereoselectivity of the MAC reaction to syn/anti = 90/10.Subsequently, different cyclization modes of methyl α, γ-dihydroxy-β-aminobutanoate were investigated, leading to the selective synthesis of functionalized 3-, 5- and 6-membered ring heterocycles, including new highly functionalized oxazolidinones et oxazolines. In contrast, despite considerable efforts, we were unable to induce cyclisation to forma a 4-membered ring heterocycle, due to the surprising lack of nucleophilicity of the free alcohol function in the acyclic precursors.In a second study, we examined the oxyhomologation of Garners aldehyde, a cyclicN,O-protected derivative of L-serinal, using a selection of nucleophiles via one-pot MAC methodology. These reactions furnished protected ester and amide derivatives of α, γ-dihydroxy-β-aminobutyric acid in good yields with an anti diastereoselectivity with a ratio as high as syn/anti = 10/90 when H-MAC-TBDPS was used as the MAC reagent. These are the first known examples of MAC reactions which proceed with anti diastereoselectivity.Functionalized 3- and 5-membered ring heterocycles were prepared from these adducts,and via selective oxidation at the γ-position,orthogonally-protected derivatives of erythro-β-hydroxyaspartic acid and erythro-β-hydroxyasparagine were prepared.

No description available.

Israel Zangwill, novelist, playwright, poet, and essayist, can be understood and appreciated best as an apologist whose chosen mission was to introduce the Jew to the English-speaking reader, a reader who had often see the word Jew on the pages of his literature but seldom had been able to meed an authentic specimen of the group in--or out--of print. This thesis will describe the works of Zangwill from an apologetic standpoint.

The present study was firstly aimed at producing the AM fungal inocula by using soil-based and soil-less culture techniques, including the in-vitro axenic technique, and secondly to assess the infectivity and effectiveness of the inocula so produced in glasshouse and field conditions. Indigenous AM fungi from 5 different sites of New South Wales were successfully propagated and multiplied using the pot-culture and atomizing disc aeroponic culture techniques, and their infectivity was measured using the MPN bioassay method. The coarse and fine sand mix was proven to be very effective for the production of AM fungal inocula. The findings indicated that aeroponic culture technique is far superior to that of conventional pot-culture technique, and could possibly substitute the most commonly used pot-culture technique of AM fungal inoculum production. The ultra-sonic nebulizer technology could possibly be an alternative to conventional aeroponic systems for producing AM fungal isolates in commercial quantities. The introduction of the sheared-root inoculum of Glomus intraradices, produced by the ultra-sonic nebulizer technique, into agricultural soils can substantially reduce the intake of P-fertilizers as much as 50% of the recommended level. The study also indicated that soil phosphorus is a critical factor in limiting mycorrhizal colonization, possibly limiting mycorrhizal responses.The research suggests that various commercially produced single or 'cocktail' inocula may work on mycorrhiza dependent plants in soils where the indigenous AM flora is either not abundant and/or efficient. Furthermore, ecophysiology of the same AM species have different effects on plant growth. / Doctor of Philosophy (PhD)