abstract: Atmospheric particulate matter has a substantial impact on global climate due to its ability to absorb/scatter solar radiation and act as cloud condensation nuclei (CCN). Yet, little is known about marine aerosol, in particular, the carbonaceous fraction. In the present work, particulate matter was collected, using High Volume (HiVol) samplers, onto quartz fiber substrates during a series of research cruises on the Atlantic Ocean. Samples were collected on board the R/V Endeavor on West&ndash;East (March&ndash;April, 2006) and East&ndash;West (June&ndash;July, 2006) transects in the North Atlantic, as well as on the R/V Polarstern during a North&ndash;South (October&ndash;November, 2005) transect along the western coast of Europe and Africa. The aerosol total carbon (TC) concentrations for the West&ndash;East (Narragansett, RI, USA to Nice, France) and East&ndash;West (Heraklion, Crete, Greece to Narragansett, RI, USA) transects were generally low over the open ocean (0.36&plusmn;0.14 &mu;g C/m3) and increased as the ship approached coastal areas (2.18&plusmn;1.37 &mu;g C/m3), due to increased terrestrial/anthropogenic aerosol inputs. The TC for the North&ndash;South transect samples decreased in the southern hemisphere with the exception of samples collected near the 15th parallel where calculations indicate the air mass back trajectories originated from the continent. Seasonal variation in organic carbon (OC) was seen in the northern hemisphere open ocean samples with average values of 0.45 &mu;g/m3 and 0.26 &mu;g/m3 for spring and summer, respectively. These low summer time values are consistent with SeaWiFS satellite images that show decreasing chlorophyll a concentration (a proxy for phytoplankton biomass) in the summer. There is also a statistically significant (p<0.05) decline in surface water fluorescence in the summer. Moreover, examination of water&ndash;soluble organic carbon (WSOC) shows that the summer aerosol samples appear to have a higher fraction of the lower molecular weight material, indicating that the samples may be more oxidized (aged). The seasonal variation in aerosol content seen during the two 2006 cruises is evidence that a primary biological marine source is a significant contributor to the carbonaceous particulate in the marine atmosphere and is consistent with previous studies of clean marine air masses. / Dissertation/Thesis / M.S. Chemistry 2011

Resumo: Nesta pesquisa foi avaliado o metabolismo de dois genótipos de milho (Zea mays L.) ao estresse hídrico e a correlação entre o teor de compostos responsáveis pela a aclimatação à limitação hídrica desses genótipos na germinação e no estádio vegetativo. Foram instalados dois experimentos. Inicialmente, um ensaio de germinação foi montado com o objetivo de verificar a tolerância de dois genótipos de milho, DKB 390 e DAS 2B710 ao déficit hídrico e de quantificar a prolina e a trealose nos tecidos endospermático e embrionário com intuito de descrever as suas funções fisiológicas na germinação. O segundo avaliou o ajustamento osmótico através das respostas bioquímicas e fisiológicas e moleculares de dois híbridos de milho sob duas disponibilidades hídricas no solo, em um latossolo vermelho. A partir desses resultados, verificou-se a tolerância destes híbridos a seca nesse estádio e o reflexo da expressão relativa de genes relacionados à síntese de solutos compatíveis em reposta à limitação hídrica no solo / Abstract: The metabolism of maize genotypes (Zea mays L.) to soil water avaibility and the correlation between the content of compounds responsible for this acclimation to water limitation of these genotypes at the germination and the silking stage. Two experiments were carried out. First, the germination test was evaluated the tolerance of two genotypes of maize, DKB 390 and DAS 2B710 to water available and also to quantify the proline and trehalose in the endosperm and embryonary axis tissues with the aim of describe their physiological functions in germination. The second assay it was examined the osmotic adjustment through biochemical and physiological responses of two hybrids growing in two soil water availability. The results of that experiment, checking the degree of tolerance of these hybrids and the reflection of the gene expression related to synthesis of these compatible solutes in response to soil water availability / Orientador: Jairo Osvaldo Cazetta / Coorientador: José Frederico Centurion / Banca: Manuel Pedro Salema Fevereiro / Banca: Carlos Alberto Martinez Y. Huaman / Banca: Janete Aparecida Desidério / Banca: David Ariovaldo Banzatto / Doutor

Orientador: Jairo Osvaldo Cazetta / Banca: Luiz Evaldo de Moura Pádua / Banca: Leilson Costa Grangeiro / Banca: Arthur Bernardes Cecílio Filho / Banca: Fábio Henrique Tavares de Oliveira / Resumo: O fósforo é um dos nutrientes mais importantes para a cultura do meloeiro, que influencia significativamente a economia da região Nordeste. Assim, o objetivo deste trabalho foi avaliar o efeito da aplicação de doses de P na produção e qualidade de frutos de melão amarelo, cultivar Goldex F1. O experimento foi desenvolvido no Colégio Agrícola de Teresina/UFPI, entre maio e agosto de 2008. O delineamento experimental foi montado em 4 blocos casualizados em parcelas (tratamentos principais), com doses de P (0, 120, 240, 360 e 480 kg ha-1 de P2O5); as parcelas foram subdivididas no tempo (tratamentos secundários) aos 20, 27, 34, 41 e 48 dias após o transplante (DAT). Nas condições de cultivo do meloeiro em Teresina, a aplicação de doses de P2O5: 1 - A produção de frutos comerciais, massa e número de frutos comerciais por planta, diâmetro, comprimento e espessura da polpa de frutos comerciais aumentaram até a dose de 278 kg/ha P2O5; 2 - Doses acima de 278 kg/ha P2O5 prejudicaram o desenvolvimento inicial das plantas e a produção de frutos comerciais por planta; 3 - As doses de fósforo não influenciaram no teor de sólidos solúveis e acidez titulável dos frutos comerciais / Abstract: Phosphorus is a important nutrient for the melon, and this culture has significant importance for the economy in the Northeast of Brazil. Thus, the purpose of this study was to evaluate the effect of P levels on production and fruit quality of yellow melon variety Goldex F1. The experiment was conducted at the Agricultural College Teresina / UFPI between May and August 2008. The experiment was arranged in randomized blocks with five main treatments (P doses (0, 120, 240, 360 and 480 kg P2O5 ha-1) were subdivided in time (secondary treatment) at 20 , 27, 34, 41 and 48 days after transplanting (DAT). The results showed, under the conditions of this experiment, that: 1 - The productivity of comertial fruits, weight and number of comertial fruits per plant, as well as lengh and diameter of fruits and thickness of pulp increased with doses until 278 kg/ha P2O5; 2 - Doses above 278 kg/ha P2O5 tended to decrease initial planta development and production of fruit production; 3 - The phoshporus doses used do not affected significantly soluble solids and acidity of comercial fruits / Doutor

Orientador: Odair Aparecido Fernandes / Banca: Enrico de Beni Arrigoni / Banca: Celso Omoto / Banca: Sérgio de Freitas / Banca: Arlindo Leal Boiça Junior / Resumo: Com a adoção de plantas geneticamente modificadas que expressam toxinas de Bacillus thuringiensis há a necessidade de estabelecimento de estratégias para retardar o desenvolvimento da resistência de insetos, tais como áreas de refúgio. Para tanto, informações sobre a dispersão dos insetos alvo desta tecnologia são essenciais para aprimoramento de técnicas de manejo de insetos-praga. Nos estudos de dispersão normalmente são usadas técnicas de marcação-liberação-recaptura. Assim, objetivou-se com este trabalho marcar Diatraea saccharalis e avaliar a capacidade de dispersão de Spodoptera frugiperda. Para a marcação, dois corantes lipossolúveis em diferentes concentrações (100 a 400 ppm), Sudan Red 7B e Solvente Blue, foram adicionados à dieta artificial de D. saccharalis e avaliados sobre parâmetros biológicos do desenvolvimento de lagartas, pupas e adultos (fecundidade e longevidade). A adição dos corantes em dieta artificial fornecida para alimentação de lagartas de D. saccharalis proporcionou a marcação de adultos e ovos em todas as concentrações testadas. No caso da avaliação da capacidade de dispersão de S. frugiperda foram realizados experimentos durante as safras 2005/2006 e 2006/2007. A dispersão se dá por difusão e foi possível registrar distâncias máximas de recaptura de 806 m para machos e 608 m para fêmeas de S. frugiperda. / Abstract: With the adoption of genetically modified plants expressing Bacillus thuringiensis toxins there is a need of establishing strategies to delay the development of insect resistance (e.g. refugee areas). Thus, information on target insects dispersal are essential to improve pest management techniques. In dispersal studies, markingrelease- recapture techniques are usually used. The objective of this work was to mark Diatraea saccharalis and evaluate the dispersal capacity of Spodoptera frugiperda. For marking D. saccharalis, different concentrations (100 to 400 ppm) of two oil soluble dyes (Sudan Red 7B and Solvent Blue) were added to larval artificial diet. Larval and pupal development as well as adult fecundity and longevity were evaluated. The addition of dyes into the diet marked both adults and eggs, regardless the concentration used. For evaluating the dispersal capacity of S. frugiperda, experiments were carried out during 2005/2006 and 2006/2007 growing seasons. Dispersal is diffused and the maximum recapture distances were 806 m for males and 608 m for females of S. frugiperda. / Doutor

Made available in DSpace on 2016-08-15T20:31:28Z (GMT). No. of bitstreams: 1 RaimundoNLA_DISSERT.pdf: 871109 bytes, checksum: c82df3f879521a5c99ccf5bef881c54b (MD5) Previous issue date: 2015-02-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Two studies were conducted to evaluate effects of corn grain replacement with passion fruit by-product (PFB) in finishing lambs on feed intake, feedlot performance, carcass traits and digestibility. In study 1, 20 Morada Nova ram lambs (15,4±1,4kg BW) were used in a completely randomized design with 4 treatments: isonitrogenous (19% CP) experimental diets contained 30% Tifton-85 bermudagrass hay and 70% concentrate (soybean meal, wheat meal, corn and 0, 25, 50, or 75% PFB). Over a period of 21 d, lambs were housed in digestibility cages (14 d adaptation and 7 d data collection) and DM, CP and NDF digestibilities estimated by total fecal collection technique. In the study 2, 32 Morada Nova ram lambs (22.4 ± 3.2 kg BW) were housed in individual pens and assigned to a randomized block design (initial BW) and fed the same diets of study 1 for 78 d (14 d adaptation and 64 d data collection). DM and nutrient intakes, average daily gain (ADG) and gain to feed (G:F) were evaluated and after slaughter (32 kg), yields of hot carcass (HCY) and cold carcass (CCY) were calculated. Data from study 1 were analyzed using the procedure of SISVAR and means were compared with Tukey test (P < 0.05). For the study 2, data were analyzed with MIXED procedure with each animal as the experimental unit, and model effects included block and treatment. DM and CP digestibilities were not affected by PFB when it was added up to 50% (74.98 ± 2.0 and 77.38 ± 2.8%, respectively; P > 0.05). However, DM and CP digestibilities decreased in 75% PFB diet (69.7 ± 0.7 and 72.5 ± 1.1%, respectively). NDF digestibility was unaffected by treatments (P > 0.05), averaging 49.4 ± 3.4%. There were no differences in DM and digestible nutrient intakes (P > 0.05). No differences were evidenced (P > 0.05) in ADG (152 ± 0.03 g), G:F (0.147 ± 0.01 kg), HCY (46.6 ± 1.0%) and CCY (45.0 ± 1.0%). The data indicate that although passion fruit by-product decreases diets DM and CP digestibility, it is a suitable replacement for corn grain in diets for feedlot lambs when used at up to 75% / Dois estudos foram realizados para avaliar os efeitos da substituição do milho com subproduto do maracujá (SPM) na terminação de cordeiros sobre a digestibilidade, consumo, desempenho em confinamento e características de carcaça. No primeiro estudo, 20 cordeiros Morada Nova (15,4±1,4kg PC) foram usados em um delineamento inteiramente casualizado com 4 tratamentos: as dietas experimentais isonitrogenadas (19% PB) continham 30% feno Tifton-85 e 70% de concentrado (farelo de soja , farinha de trigo, milho e 0, 25, 50, ou 75% SPM. Durante um período de 21 dias, os cordeiros foram alojados em gaiolas de digestibilidade (adaptação 14 dias e 7 dias de colheita de dados) sendo a digestibilidade da MS, PB e FDN estimados pela técnica de coleta total de fezes. No segundo estudo, 32 cordeiros Morada Nova (22,4 ± 3,2 kg PC) foram alojados em baias individuais e distribuídos em delineamento em blocos casualizados, sendo alimentados com as mesmas dietas do estudo 1 por 78 dias (adaptação 14 dias e 64 dias de colheita de dados). Os consumos de matéria seca (MS) e dos nutrientes digestivos, ganho médio diário (GMD) e eficiência alimentar (EA), rendimentos de carcaça quente (RCQ) e de carcaça fria (RCF) foram avaliados e após o abate foram calculados os rendimentos de carcaça quente e fria. Os dados do primeiro estudo foram analisados utilizando o procedimento do SISVAR e as médias comparadas pelo teste de Tukey (P <0,05). Já os dados do segundo estudo foram analisados com o procedimento MIXED quando cada animal foi considerado uma unidade experimental, e no modelo foram incluídos os efeitos dos blocos e dos tratamentos. A digestibilidade da MS e da PB não foram afetadas pela SPM, quando ela foi adicionada até 50% (74,98 ± 2,0 e 77,38 ± 2,8%, respectivamente; P> 0,05). No entanto, a digestibilidade da MS e PB diminuíram com 75% de SPM na dieta (69,7 ± 0,7 e 72,5 ± 1,1%, respectivamente). A digestibilidade da FDN não foi afetada pelos tratamentos (P> 0,05), com média de 49,4 ± 3,4%. Não houve diferenças nos consumos de MS e de nutrientes digestíveis (P> 0,05). Nenhuma diferença foi evidenciada (P> 0,05) no GMD (152 ± 0,03 g), EA (0,147 ± 0,01 kg), RCQ (46,6 ± 1,0%) e RCF (45,0 ± 1,0%). Os dados indicam que, apesar do subproduto do maracujá diminuir a digestibilidade da MS e da PB das dietas, ele é um substituto adequado ao grão de milho em dietas para cordeiros confinados quando usado em até 75%

xx, 290 p. : ill. (some col.) / Macrocyclic phosphine compounds have long been sought as ligands for transition metal complexes because of their strong binding properties. Despite considerable effort in this field, no general methods for synthesizing phosphine macrocycles or their complexes have been developed. This dissertation describes attempts to synthesize an iron complex with a water-soluble macrocyclic tetraphosphine ligand for use in separating nitrogen from natural gas. Chapter I reviews previous syntheses of macrocyclic phosphine ligands and their complexes, focusing on ligand synthesis, coordination chemistry, and demetallation of the complexes. Chapter II reports on the synthesis of water-soluble secondary bidentate phosphine ligands, their coordination chemistry with iron(II), and attempts to use these complexes as templates for forming a macrocyclic iron-phosphine complex by reactions with carbon electrophiles. Over the course of treating these iron complexes with various carbon electrophiles, an interesting reaction between bromomaleic anhydride and proton sponge was discovered. Chapter III explores the product, 4-maleicanhydrido-1,8-bis-(dimethylamino)naphthalene (MAPS). Due to its conjugated donor-acceptor network, which is disrupted upon protonation, MAPS acts as a colorimetric version of a proton sponge. The attachment of MAPS to amine-functionalized solid supports, forming solid-supported proton sponge reagents, is also described. Chapter IV discusses the synthesis of an iron(II) complex of the water-soluble phosphine 1,2-bis(di(hydroxymethyl)phosphino)ethane (DHMPE). Although unbound hydroxymethylphosphines commonly react with NH-functional amines via the phosphorus Mannich reaction, this and other complexes of DHMPE do not undergo this reaction. Further investigation with hydroxymethylphosphine-boranes suggests that the currently-accepted mechanism of the phosphorus Mannich reaction is incorrect, and an alternate mechanism is proposed. Chapter V discusses the synthesis and functionalization of copper(I) complexes of water-soluble phosphines. Unlike the complexes described in Chapter I, these complexes readily react with α,ω-dihalides or di(acyl chloride)s, forming complexes whose mass spectra correspond to those with macrocyclic phosphine ligands. Unlike most macrocyclic tetraphosphine complexes, these complexes can be demetallated by treatment with sulfide. Finally, a new synthesis of water-soluble macrocycles, based on lessons learned during the course of these investigations, is proposed. This dissertation includes previously published and unpublished co-authored material. / Committee in charge: Dr. Michael M. Haley, Chairperson; Dr. David R. Tyler, Advisor; Dr. Darren W. Johnson, Member; Dr. Shih-Yuan Liu, Member; Dr. Mark H. Reed, Outside Member

Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-09-17Bitstream added on 2014-06-13T20:05:53Z : No. of bitstreams: 1 abreu_flg_dr_jabo.pdf: 516269 bytes, checksum: 13df4ee9b7a423e1d9c966824d142925 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O fósforo é um dos nutrientes mais importantes para a cultura do meloeiro, que influencia significativamente a economia da região Nordeste. Assim, o objetivo deste trabalho foi avaliar o efeito da aplicação de doses de P na produção e qualidade de frutos de melão amarelo, cultivar Goldex F1. O experimento foi desenvolvido no Colégio Agrícola de Teresina/UFPI, entre maio e agosto de 2008. O delineamento experimental foi montado em 4 blocos casualizados em parcelas (tratamentos principais), com doses de P (0, 120, 240, 360 e 480 kg ha-1 de P2O5); as parcelas foram subdivididas no tempo (tratamentos secundários) aos 20, 27, 34, 41 e 48 dias após o transplante (DAT). Nas condições de cultivo do meloeiro em Teresina, a aplicação de doses de P2O5: 1 – A produção de frutos comerciais, massa e número de frutos comerciais por planta, diâmetro, comprimento e espessura da polpa de frutos comerciais aumentaram até a dose de 278 kg/ha P2O5; 2 - Doses acima de 278 kg/ha P2O5 prejudicaram o desenvolvimento inicial das plantas e a produção de frutos comerciais por planta; 3 – As doses de fósforo não influenciaram no teor de sólidos solúveis e acidez titulável dos frutos comerciais / Phosphorus is a important nutrient for the melon, and this culture has significant importance for the economy in the Northeast of Brazil. Thus, the purpose of this study was to evaluate the effect of P levels on production and fruit quality of yellow melon variety Goldex F1. The experiment was conducted at the Agricultural College Teresina / UFPI between May and August 2008. The experiment was arranged in randomized blocks with five main treatments (P doses (0, 120, 240, 360 and 480 kg P2O5 ha-1) were subdivided in time (secondary treatment) at 20 , 27, 34, 41 and 48 days after transplanting (DAT). The results showed, under the conditions of this experiment, that: 1 – The productivity of comertial fruits, weight and number of comertial fruits per plant, as well as lengh and diameter of fruits and thickness of pulp increased with doses until 278 kg/ha P2O5; 2 - Doses above 278 kg/ha P2O5 tended to decrease initial planta development and production of fruit production; 3 – The phoshporus doses used do not affected significantly soluble solids and acidity of comercial fruits

Alkali-soluble resins (ASRs) were prepared by (i) solution and (ii) emulsion polymerization. All ASRs were synthesized with number-average molar masses < 20,000 g mol-1 and all had 15 wt% methacrylic acid 5 wt% styrene, the remaining 80 wt% was composed of either methyl methacrylate or a combination of methyl methacrylate and ethyl acrylate. All emulsion ASRs were made to 20% solids, with volume-average particle diameters (dv) in the region 30 – 50 nm, with a glass transition temperature of 80 – 120 °C. Emulsion polymerization was the preferred route for ASR synthesis, to allow further studies on their dissolution behaviour. Before their use as colloidal stabilizers, the dissolution behaviour of the ASRs needed to beinvestigated e.g. effect of temperature, molar mass, and composition. Particle size and absorbance measurements were taken during dissolution of ASRs to achieve 100%neutralization and these were shown to have two stages, an apparent particle swelling (whichwas rapid), and a slower, decrease in particle size as water-soluble polymeric material wasdiffusing out of the ASR particles. From this, further interpretation allowed for calculating the diffusion coefficient of the ASR polymer using the Stokes-Einstein equation. Time-domain nuclear magnetic resonance (TD-NMR) was employed to enhance understanding of what is occurring in the ASR particles, and in the aqueous, continuous phase. The final aspect of this project was to use the ASRs prepared as colloidal stabilizers in emulsion polymerizations of butyl acrylate (BA) and butyl methacrylate (BMA) using varying levels and also the effect of adding additional surfactant. The results show that the effect of ASR molar mass, the concentration of stabilizer, and also the impact of the EA-containing ASR greatly influence stability, whereby lower ASR molar mass, higher levels of stabilizer and including EA greatly benefit colloidal stability in PBA latexes. In PBMA latexes, a similar trend was also observed, but, the presence of ethyl acrylate (EA) in the ASR backbone has a detrimental effect on the colloidal stability, caused by the inability of grafting to occur between the ASR and PBMA.

Made available in DSpace on 2014-06-11T19:28:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-09Bitstream added on 2014-06-13T19:36:52Z : No. of bitstreams: 1 watanabe_ph_me_jabo.pdf: 815252 bytes, checksum: f9db9992d6146fd2baf2b6e640ff6d42 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foram conduzidos dois ensaios para avaliar a utilização da polpa cítrica como ingrediente em programas de restrição alimentar qualitativa para suínos em terminação. No primeiro ensaio foram utilizados 16 suínos machos castrados da linhagem Topigs, com peso inicial de 80,5l4,7 kg, para a avaliação biológica da polpa cítrica. Por apresentar 18,85% de fibra em detergente neutro e 41,18% de fibra solúvel em detergente neutro, a polpa cítrica mostrou-se como um ingrediente viável a ser utilizado em programas de restrição alimentar qualitativa. No segundo ensaio foram utilizados 36 suínos machos castrados com peso inicial de 83,7l5,1 kg, recebendo rações com níveis de 0, 10, 20 e 30% de polpa cítrica. Os animais foram abatidos com peso próximo de 130 kg, sendo avaliados quanto ao desempenho, pesos de órgãos do trato digestório, parâmetros séricos, características de carcaça, qualidade da carne e avaliação econômica do uso das dietas. Até 10% de inclusão, a polpa cítrica não piorou o desempenho, porém observou-se reduções no peso e rendimento das carcaças devido ao aumento dos pesos dos órgãos do trato digestório. A inclusão de polpa cítrica não piorou a qualidade da carne, podendo ser utilizada na alimentação de suínos em terminação, entretanto, sua inclusão não proporcionou retorno econômico que justificasse seu uso em programas de restrição alimentar. / Two assays were conducted to evaluate citrus pulp as an ingredient in qualitative feed restriction programs for growing pigs. In the first assay, 16 barrows of Topigs lineage with 80.5l4.7 kg of body weight were used to determine the biological value of citrus pulp. The citrus pulp presented 18.85% of neutral detergent fiber and 41.18% of neutral detergent soluble fiber, and was considered as a viable ingredient to be used in qualitative feed restriction programs. In the second assay, 36 barrows initially weighing 83.7l5.1 kg were allotted into four diets with different levels (0, 10, 20 and 30%) of citrus pulp. Animals were fed until they reached 130 kg. At this moment, pigs were abated and the effects on performance, weight of gastrointestinal tract organs, serum parameters, carcass traits, meat quality and economical analysis were evaluated. Up to 10% of inclusion, citrus pulp did not act negatively on animal s performance but body weight and total dressing were reduced due to higher weight of gastrointestinal tract organs. As citrus pulp did not cause any undesirable effects on meat quality, this ingredient was shown as an alternative in diets for finishing pigs. However, the economic analysis demonstrated that the inclusion of citrus pulp in diets was not profitably enough to justify its use in feed restriction programs, as no better reward indexes were observed.

Made available in DSpace on 2015-03-26T13:55:08Z (GMT). No. of bitstreams: 1 texto completo.pdf: 337392 bytes, checksum: fe191b2d9ab148e2398deaa665aca657 (MD5) Previous issue date: 2006-10-02 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Two experiments were conducted to evaluate the nutritive value, the profile of fermentation of sorghum silage produced with addition urea doses and two storage periods and to determine nitrogen and carbohydrates fractions of the silages. The PVC silos with 50 cm of height and 10 cm of diameter were used to sorghum storage. In the experiment I, the evaluation of the nutritional value of the silages was accomplished through the determination of the chemical composition and in vitro dry matter disappearance (IVDMD) of the silages and, the fermentation profile, through the determination of the contents of ammonia-N, values pH and WSC of the silages. The urea addition in the production of the sorghum silage was shown with potential of minimizing losses of DM of the silage. The urea addition in the sorghum ensilage increased the contents of CP, NDIP and the IVDMD of the silages and it reduced the contents of NDF, ADF, cellulose and lignin. The storage period had effect on the contents of NDF, ADF, cellulose and lignin. In relation to the inherent variables to the fermentative characteristics of the silages, the urea doses had quadratic effect on the contents of ammonia-N of the silages. The values of pH of the silages increased lineary. There was effect of the storage periods on the contents ammonia-N and pH value. There was interaction between urea doses and storage period, only on the pH value. However, the urea addition in the sorghum ensilage did not damage fermentation profile of silages and it can improve his nutritive value. In the experiment II, crude protein and CT fractions of the silages were determined and evaluated. The nitrogen fractions of the silages were influenced by the urea addition, being verified positive lineal effect for the contents of the A fraction, negative lineal effect for B1+B2, B3 and C fractions. The regression analysis detected lineal reduction of the contents of CT in function of the urea addition. The fractions of CT were influenced by the urea addition, being verified negative lineal effect on the contents of the A+B1 fraction, positive lineal effect about the B2 fraction and positive lineal effect for the content of the C fraction inside of the period of 60 days. / Dois experimentos foram conduzidos no delineamento inteiramente casualizado para avaliar o valor nutritivo, o perfil de fermentação de silagem de sorgo produzida com a adição de doses crescentes de uréia e dois períodos de armazenamento e determinar as frações protéicas e dos carboidratos da silagem. Foram usados silos de PVC com 50 cm de altura e 10 cm de diâmetro para o armazenamento do sorgo. No experimento I, a avaliação do valor nutritivo das silagens foi realizada através da determinação da composição química e da digestibilidade in vitro da matéria seca das silagens e, o perfil de fermentação, através da determinação dos teores de nitrogênio amoniacal, dos valores de pH e dos teores de carboidratos solúveis (CHOS) das silagens. A adição de uréia na produção da silagem de sorgo mostrou-se com potencial de minimizar perdas de matéria seca (MS) da silagem. A adição de uréia na ensilagem de sorgo aumentou os teores de proteína bruta (PB), proteína insolúvel em detergente neutro (PIDN), digestibilidade in vitro da matéria seca (DIVMS) das silagens e diminuiu os teores de fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), celulose e lignina. O período de armazenamento teve efeito sobre os teores de FDN, FDA, celulose e lignina. Em relação às variáveis inerentes às características fermentativas das silagens, as doses de uréia tiveram efeito quadrático sobre o teor de nitrogênio amoniacal das silagens. Os valores de pH das silagens aumentaram linearmente. Houve efeito significativo dos períodos de armazenamento sobre o teor de nitrogênio amoniacal e valor de pH. Houve efeito de interação entre doses de uréia e período de armazenamento, apenas sobre o valor de pH. Entretanto, a adição de uréia na ensilagem de sorgo não prejudicou o perfil de fermentação das silagens e pode melhorar o valor nutritivo das mesmas. No experimento II, foram determinadas e avaliadas as frações que constituem a PB e os carboidratos totais (CHO) das silagens. As frações nitrogenadas (A, B1+B2, B3 e C) das silagens foram influenciadas pela adição de uréia, constatando-se efeito linear positivo para os teores da fração A, efeito linear negativo para as frações B1+B2, B3 e C. A análise de regressão detectou redução linear do teor de CHO em função da adição de uréia. As frações de CHO (A+B1, B2 e C) foram influenciadas pela adição de uréia, constatando-se efeito linear negativo sobre os teores da fração A+B1, efeito linear positivo sobre a fração B2 e efeito linear positivo para o teor da fração C dentro do período de 60 dias.