O presente estudo objetiva mostrar ao Cirurgião Dentista, os quesitos necessários para se formar um Odontólogo apto a praticar a sedação inalatória, bem como os itens de segurança e de respaldo legal que deverão compor o seu ambiente de trabalho ao se utiliza desta técnica. O estudo foi fundamentado a partir de revisão de literatura sobre o tema, tendo como metodologia o estilo de Vancouver. A analgesia inalatória pela mistura gasosa de óxido nitroso e oxigênio constitui um excelente instrumento no controle da dor e da ansiedade dos pacientes durante o tratamento odontológico. É importante observar que a técnica de analgesia inalatória pela mistura gasosa de óxido nitroso e oxigênio deve ser realizada por meio de normatização técnica para garantir a eficiência da técnica e evitar transtornos. O roteiro proposto no trabalho visa apresentar as características de segurança e detalhamento das especificações técnicas dos estabelecimentos de assistência odontológica para o emprego da técnica de analgesia inalatória pela mistura gasosa de óxido nitroso e oxigênio. / This study has as objective to suggest a number of propositions in order to prepare and develop a dental office to perform conscious sedation by inhalatory analgesia using nitrous oxide/oxygen mixture. It was based on the revision of literature about the subject, having as methodology the Vancouver style. The conscientious sedation constitutes an excellent instrument in the control of the patient?s anxiety during dental treatment. It also will show to the Dentist the necessary requirements to the training of his personal and himself. It is important to observe that the technique itself must follow normative rules to guarantee its efficiency. The scope considered in the work aims present characteristics of security and detailed specifications to establish dental assistance for the use of conscious sedation by nitrous oxide/oxygen mixture.

Submitted by Francine Silva (francine.silva@unipampa.edu.br) on 2019-03-25T14:21:04Z No. of bitstreams: 1 Fluxo de gases de efeito estufa em solos do pampa gaúcho sob Silvicultura.pdf: 731174 bytes, checksum: dbbab000c0161ef5446f57a10d836639 (MD5) / Made available in DSpace on 2019-03-25T14:21:04Z (GMT). No. of bitstreams: 1 Fluxo de gases de efeito estufa em solos do pampa gaúcho sob Silvicultura.pdf: 731174 bytes, checksum: dbbab000c0161ef5446f57a10d836639 (MD5) Previous issue date: 2013-12-12 / A região do Pampa Gaúcho está passando por modificação do tipo de uso do solo, com a inserção da silvicultura em solos de pastagens ou agricultura. No entanto, pouco se conhece sobre o impacto que tal mudança implica no fluxo dos Gases de Efeito Estufa (GEE) nessa região, especialmente em relação aos fluxos de metano (CH4) e óxido nitroso (N2O) do solo. Este estudo teve como objetivo principal avaliar a inserção da silvicultura, com Acacia mearnsii De Wild e Eucalyptus saligna, em áreas de campo nativo e o seu efeito no fluxo CH4 e N2O do solo, e determinar os principais fatores de solo que governam os fluxos destes gases. Dois experimentos foram realizados durante o período de um ano, em povoamentos de Acacia mearnsii De Wild avaliando quatro tratamentos: Acácia (AM), Acácia com retirada manual de serrapilheira (A-s), Acácia recém colhida (AC) e campo nativo (CN); e de Eucalyptus saligna avaliando cinco tratamentos: Eucalipto com quatro anos (E4), Eucalipto com quatro anos com retirada manual da serrapilheira (E4-s), Eucalipto com dois anos (E2), Mata Nativa (MN) e Campo Nativo (CN), utilizando o campo nativo como tratamento de referência. As amostras de ar foram coletadas quinzenalmente pelo método de câmaras estáticas e os teores dos gases foram determinados por cromatografia gasosa. Em cada evento de amostragem de ar, foram avaliados a umidade e os teores de nitrogênio mineral do solo, coletada a serrapilheira e monitorada a temperatura do solo e do ar dentro da câmara. A inserção tanto do eucalipto como de acácia não alterou significativamente os fluxos de CH4 e N2O do solo em relação ao campo nativo adjacente a cada floresta. Os fluxos de N2O foram geralmente baixos, com a maioria dos valores entre –5 e 30 μg N m-2 h-1, provavelmente favorecidas pela baixa precipitação do período avaliado e dos baixos teores de nitrogênio mineral do solo. Houve predomínio de oxidação de CH4 nos solos sob silvicultura no período avaliado, em magnitude similar ao campo nativo. O solo sob eucalipto com dois anos tendeu a emitir mais N2O do que com quatro anos. A colheita da acácia promoveu aumento da emissão de N2O, provavelmente decorrente da maior disponibilidade de nitrogênio mineral no solo para os processos de nitrificação e desnitrificação. Em relação ao CH4, a maior emissão coincidiu com os períodos de temperatura do solo mais elevada, o que é coerente com o aumento da atividade biológica, principalmente em áreas com menor cobertura vegetal. Os teores de carbono orgânico total (COT) e nitrogênio total (NT) do solo sob eucalipto e acácia não diferiram significativamente do campo nativo para a ampla maioria das camadas avaliadas. Somado aos baixos fluxos de CH4 e N2O da silvicultura, o sequestro de carbono via biomassa vegetal e produtos madeireiros sugerem que a mudança de uso do solo com inserção de silvicultura seja uma opção efetiva para a mitigação dos GEE e aumento do sequestro de carbono em áreas da região do Pampa Gaúcho. / The soil use in the region of the Pampa Gaúcho has been modified by of forestation in soils previously used for agriculture or grazing. However, little is known about the impact of this change on greenhouse gases (GHG) fluxes in the soil in that region, mainly regarded to the methane (CH4) and nitrous oxide (N2O). This study aimed to evaluate the effect of the conversion of native grassland to forestry, with Acacia mearnsii De Wild and Eucalyptus saligna, in the Pampa Gaúcho on the soil CH4 and N2O fluxes, besides determining the soil variables that govern these fluxes. Two experiments were conducted for one year, in plantations of Acacia mearnsii De Wild evaluating four treatments: Acacia (AM), Acacia with manual litter removal (A-s), Acacia recently harvested (AH) and native grassland (NG); and Eucalyptus saligna evaluating five treatments: four–year Eucalyptus plantation (E4), four– year Eucalyptus plantation with manual litter removal (E4-l), two–year Eucalyptus plantation (E2), Native forest (NF) and Native grassland (NG), using the native grassland as reference treatment. The air samples were taken biweekly by the method of static chambers and gas concentrations were determined by gas chromatography. In each sampling event, we evaluated the soil moisture and mineral nitrogen content, deposition of litter and monitored the soil and chamber air temperature. The forestation with both eucalyptus and acacia did not alter significantly the soils fluxes of CH4 and N2O in comparison to the native grassland adjacent to each forest. The N2O flux are generally low, with most values ranging from –5 to 30 μg N m-2 h-1, probably favoured by the low rainfall and soil mineral nitrogen levels during the evaluated period. Similarly magnitude to the soil under native grassland, CH4 oxidation predominated in forested soils in the period of the experiment. The soil with two-year old eucalyptus plantation tended to emit more N2O than the four-year plantation. The harvest of acacia increased the soil N2O emission, likely due to the larger availability of mineral N in the soil for the nitrification and denitrification processes. With respect to CH4, the largest emission coincided with periods of higher soil temperature, which is coherent herewith increased of the biological activity, especially in areas with less vegetation cover. The contents of total organic carbon (TOC) and total nitrogen (TN) in soils with eucalyptus and acacia were not significantly different from those observed in native grassland soil for most layers. The low CH4 and N2O emissions from forestry added to the carbon sequestration in the plant biomass and wood products suggests that the change of land use for forestation is an effective option for mitigating the GHG emissions and for increasing the carbon sequestration in areas such as the Pampa Gaúcho.

Poucos estudos têm avaliado as emissões de óxido nitroso (N2O) e alterações na qualidade biológica de solos sob aplicação de dejetos de animais no Sul do Brasil. A presente pesquisa objetivou avaliar o impacto da aplicação de dejetos líquidos de suínos e de bovinos, e de cama de aviário sobre as emissões de N2O (Estudo I) e em indicadores microbiológicos de um Gleissolo (Estudo II), em comparação à aplicação de uréia e sem aplicação de N (tratamento controle). A aplicação dos dejetos de animais e da uréia foi realizada sobre a palhada dessecada de azevém quando da implantação da cultura do milho, e as doses foram equivalentes a aplicação de 150 kg N ha-1 em todos os tratamentos. As emissões de N2O foram avaliadas, pelo método da câmara estática, durante os sete dias que sucederam a aplicação dos dejetos. A concentração de N2O nas amostras de ar foi analisada por cromatografia gasosa. Os indicadores microbiológicos do solo (0-10 cm) foram avaliados aos 5, 10, 20, 30 e 120 dias após a aplicação dos tratamentos. As taxas de emissão de N2O do solo variaram entre 74 e 2969 μg N m-2 h-1, sendo os menores fluxos verificados nos tratamentos sem aplicação de N (147-186 μg N m-2 h-1) e com uréia (74-201 μg N m-2 h-1). A aplicação dos dejetos de animais promoveu sensível aumento nas emissões de N2O em comparação à uréia, com destaque para os dejetos de suínos que apresentou uma emissão acumulada de 1,7 kg N-N2O ha-1 a qual foi muito superior à observada com dejetos de bovinos (0,93 kg ha-1) e de cama de aviário (1,00 kg ha-1). O efeito das fontes de N nos indicadores microbiológicos do solo ocorreu principalmente logo após a sua aplicação (5 dias) e, de maneira geral, observaram-se aumento do C e N na biomassa microbiana e da atividade das enzimas β- glicosidase e urease. Entretanto, esse efeito foi bastante efêmero e, aos 10 dias após a aplicação dos dejetos de suínos e de bovinos, e da uréia, restringiu-se em média à 63% da magnitude verificada aos 5 dias para o Cmic, e já havia desaparecido totalmente nos indicadores Cmic:Corg e atividade da β-glicosidase. Baseado num índice que integra os diversos indicadores, a cama de aviário promoveu melhores condições para a microbiota do solo em comparação aos demais dejetos. Esse resultado, ao menos em parte, se deveu ao seu efeito mais prolongado sobre a maioria dos indicadores microbiológicos avaliados. Possivelmente a aplicação parcelada pode aumentar a eficiência dos dejetos de suínos no suprimento de N para as culturas, reduzir a emissão de N2O do solo, e apresentar benefícios quanto ao seu efeito na qualidade microbiológica de solos agrícolas. / Few studies have evaluated manure effects on nitrous oxide (N2O) emissions and on microbial attributes of soil in Southern Brazil. This study aimed to evaluate the impact of pig slurry, cattle manure, and poultry manure on N2O emissions and on biological quality indicators of a no-tilled Gleisol, in comparison with urea application and without N application (control treatment). Manures and urea were applied in a rate of 150 kg ha-1 of N on rye-grass straw just before the corn sowing. The static chamber method was used to evaluate soil N2O emissions. Air sampling was performed through the seven days after manure application and the N2O concentration in the samples was analyzed by gas chromatography. The microbial indicators of soil quality were evaluated at 5, 10, 20, 30 and 120 days after manure application. The fluxes of N2O varied from 74 and 2969 μg N m-2 h-1, and the lowest fluxes were verified in the treatments without N application (147 e 186 μg N m-2 h-1) and with urea (74 e 201 μg N m-2 h-1). Manure application promoted a sensible increase on soil N2O emissions in comparison with urea. Pig slurry resulted in the highest accumulated emission of 1.7 kg N-N2O ha-1 that was higher than that observed with cattle manure (0.93 kg N-N2O ha-1) and with poultry manure (1.00 kg NN2O ha-1). The effect of N sources on microbial soil attributes were more intense in the immediate period after application (5 days) and, in general, increased Cand N-microbial biomass and the activities of β-glicosidase and urease enzyme. However, their effects were of short-term and decreased rapidly in the next period. After 10 days of manure application the majority microbial attributes did not showed the beginning effect. A integrative index of the several microbial soil attributes indicated that poultry manure promoted the best soil conditions to microbial in comparison with the other manures and this result was, in part at least, due to the more extended effect on soil microorganisms. In manure-based production systems, the split applications of pig slurry probably it will be favorable to increase the efficiency in N supply to the crops and mitigate the N2O emissions, in addition to be a better option to improve biological quality of agricultural soils.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-04-18T18:54:16Z No. of bitstreams: 1 2012 - Abmael da Silva Cardoso.pdf: 1600160 bytes, checksum: 714351549deda5ed89c5e1ae3f665e30 (MD5) / Made available in DSpace on 2017-04-18T18:54:16Z (GMT). No. of bitstreams: 1 2012 - Abmael da Silva Cardoso.pdf: 1600160 bytes, checksum: 714351549deda5ed89c5e1ae3f665e30 (MD5) Previous issue date: 2012-01-27 / CAPES / The production of beef cattle in Brazil is responsible for much of the anthropogenic emission of greenhouse gases (GHG) emissions, especially methane from enteric fermentation and nitrous oxide from animal excretion. Changes in pasture management cattle diets may reflect a reduction in greenhouse gas emissions per unit of product produced. The objectives of this study were to simulate the effect of emission of greenhouse gases at different levels of intensification of beef production in Brazil, applying appropriate emission factors, and to assess the effect of changes in soil carbon stocks on the carbon balance. Four scenarios were established: number 1 - animals spent the entire cycle in areas of degraded pastures and extensive system; 2 - the animals spent the entire cycle on improved pastures but under an extensive system; 3 - the animals were raised on extensive improved pastures and supplemented in growing and fattening systems; and 4 - the animals were raised on pastures with intensive finishing in feedlots. The estimates of the GHG emissions were based on Brazilian studies of the zootecnic characteristics for each scenario. Using the methodology of the IPCC Tier 2 in the Scenario 2, the annual amount of CO2 emitted per carcass produced was 35.47 % lower than scenario 1; less than 18.85% in scenario 3 compared to scenario 2; and 19.6% lower in scenario 4 compared to scenario 3. Thus the intensification of production systems reduced the carbon emission per unit of product. Among the different factors used to compute the GHG balance, the application of Brazilian originated factors showed lower emissions per kg of product, and the methodology that uses the level of detail 2 of IPCC the highest. When the carbon sequestered by the soil was included in the balance, the mitigation values increase to 83.92% when comparing scenario 1 with 4, pointing to an even greatest mitigation potential per unit of product. The association between intensification and pasture recovery with carbon sequestration by soil presented a mitigation potential from 14.91 to 83.92% of emissions per unit of product. / A produ??o de bovinos de corte ? respons?vel no Brasil por grande parte da emiss?o de gases de efeito estufa (GEE), especialmente metano pela fermenta??o ent?rica dos animais e ?xido nitroso pela excre??o. Mudan?as no manejo e alimenta??o de animais bovinos podem repercutir numa redu??o das emiss?es destes gases por unidade de produto produzida. O objetivo deste trabalho foi verificar o efeito da emiss?o de gases de efeito estufa em diferentes n?veis de intensifica??o da pecu?ria de corte no Brasil aplicando diferentes fatores de emiss?o, bem como avaliar o efeito do sequestro de carbono sobre o balan?o de carbono. Quatro cen?rios foram estabelecidos: no primeiro os animais passavam todo o ciclo em ?reas com pastagens degradadas e sistema extensivo; no segundo os animais tinham o ciclo completo em pastagens resolutivas e sistema extensivo; no terceiro os animais eram criados em sistema extensivo em pastagens melhoras e com suplementa??o na recria e engorda; e no quarto sistema os animais eram criados em pastagens manejadas intensivamente com engorda em confinamento. A emiss?o de GEE para cada cen?rio foi calculada em fun??o das caracter?sticas zoot?cnicas e com base em estudos nacionais. Foi utilizada a metodologia do IPCC Tier 2 para o Cen?rio 2, a quantidade anual de CO2 emitido por carca?a produzida foi 35,47% menos em rela??o ao cen?rio 1, menos 18,85% no cen?rio 3 em rela??o ao cen?rio 2, e 19,6% menos no cen?rio 4 em rela??o ao cen?rio 3. Portanto a intensifica??o da bovinocultura de corte reduz a pegada de carbono da carne bovina. Entre os diferentes fatores usados para o balan?o de GEE o com fatores nacionais apresentou menor emiss?o por quilo de produto, e o m?todo com o n?vel de detalhamento 2 do IPCC a maior emiss?o. Quando inclusos os valores de carbono sequestrado pelo solo no balan?o, os valores de mitiga??o aumentaram para 83,92% entre o cen?rio 1 e 4, apontando para um potencial de mitiga??o ainda maior por unidade de produto. A associa??o entre intensifica??o e recupera??o das pastagens com sequestro de carbono pelo solo apresentou potencial de mitiga??o entre 14,91 e 83,92% das emiss?es por unidade de produto.

Submitted by Sandro Camargo (sandro.camargo@unipampa.edu.br) on 2015-05-07T23:21:07Z No. of bitstreams: 1 111010005.pdf: 731177 bytes, checksum: 3340e7380683d381f6e08622380ed7db (MD5) / Made available in DSpace on 2015-05-07T23:21:07Z (GMT). No. of bitstreams: 1 111010005.pdf: 731177 bytes, checksum: 3340e7380683d381f6e08622380ed7db (MD5) Previous issue date: 2012-12-12 / A região do Pampa Gaúcho está passando por modificação do tipo de uso do solo, com a inserção da silvicultura em solos de pastagens ou agricultura. No entanto, pouco se conhece sobre o impacto que tal mudança implica no fluxo dos Gases de Efeito Estufa (GEE) nessa região, especialmente em relação aos fluxos de metano (CH 4 ) e óxido nitroso (N 2 O) do solo. Este estudo teve como objetivo principal avaliar a inserção da silvicultura, com Acacia mearnsii De Wild e Eucalyptus saligna, em áreas de campo nativo e o seu efeito no fluxo CH 4 e N 2 O do solo, e determinar os principais fatores de solo que governam os fluxos destes gases. Dois experimentos foram realizados durante o período de um ano, em povoamentos de Acacia mearnsii De Wild avaliando quatro tratamentos: Acácia (AM), Acácia com retirada manual de serrapilheira (A-s), Acácia recém colhida (AC) e campo nativo (CN); e de Eucalyptus saligna avaliando cinco tratamentos: Eucalipto com quatro anos (E4), Eucalipto com quatro anos com retirada manual da serrapilheira (E4-s), Eucalipto com dois anos (E2), Mata Nativa (MN) e Campo Nativo (CN), utilizando o campo nativo como tratamento de referência. As amostras de ar foram coletadas quinzenalmente pelo método de câmaras estáticas e os teores dos gases foram determinados por cromatografia gasosa. Em cada evento de amostragem de ar, foram avaliados a umidade e os teores de nitrogênio mineral do solo, coletada a serrapilheira e monitorada a temperatura do solo e do ar dentro da câmara. A inserção tanto do eucalipto como de acácia não alterou significativamente os fluxos de CH 4 e N 2 O do solo em relação ao campo nativo adjacente a cada floresta. Os fluxos de N 2 O foram geralmente baixos, com a maioria dos valores entre –5 e 30 μg N m -2 h -1 , provavelmente favorecidas pela baixa precipitação do período avaliado e dos baixos teores de nitrogênio mineral do solo. Houve predomínio de oxidação de CH 4 nos solos sob silvicultura no período avaliado, em magnitude similar ao campo nativo. O solo sob eucalipto com dois anos tendeu a emitir mais N 2 O do que com quatro anos. A colheita da acácia promoveu aumento da emissão de N 2 O, provavelmente decorrente da maior disponibilidade de nitrogênio mineral no solo para os processos de nitrificação e desnitrificação. Em relação ao CH 4 , a maior emissão coincidiu com os períodos de temperatura do solo mais elevada, o que é coerente com o aumento da atividade biológica, principalmente em áreas com menor cobertura vegetal. Os teores de carbono orgânico total (COT) e nitrogênio total (NT) do solo sob eucalipto e acácia não diferiram significativamente do campo nativo para a ampla maioria das camadas avaliadas. Somado aos baixos fluxos de CH 4 e N 2 O da silvicultura, o sequestro de carbono via biomassa vegetal e produtos madeireiros sugerem que a mudança de uso do solo com inserção de silvicultura seja uma opção efetiva para a mitigação dos GEE e aumento do sequestro de carbono em áreas da região do Pampa Gaúcho. / The soil use in the region of the Pampa Gaúcho has been modified by of forestation in soils previously used for agriculture or grazing. However, little is known about the impact of this change on greenhouse gases (GHG) fluxes in the soil in that region, mainly regarded to the methane (CH 4 ) and nitrous oxide (N 2 O). This study aimed to evaluate the effect of the conversion of native grassland to forestry, with Acacia mearnsii De Wild and Eucalyptus saligna, in the Pampa Gaúcho on the soil CH 4 and N 2 O fluxes, besides determining the soil variables that govern these fluxes. Two experiments were conducted for one year, in plantations of Acacia mearnsii De Wild evaluating four treatments: Acacia (AM), Acacia with manual litter removal (A-s), Acacia recently harvested (AH) and native grassland (NG); and Eucalyptus saligna evaluating five treatments: four–year Eucalyptus plantation (E4), four– year Eucalyptus plantation with manual litter removal (E4-l), two–year Eucalyptus plantation (E2), Native forest (NF) and Native grassland (NG), using the native grassland as reference treatment. The air samples were taken biweekly by the method of static chambers and gas concentrations were determined by gas chromatography. In each sampling event, we evaluated the soil moisture and mineral nitrogen content, deposition of litter and monitored the soil and chamber air temperature. The forestation with both eucalyptus and acacia did not alter significantly the soils fluxes of CH 4 and N 2 O in comparison to the native grassland adjacent to each forest. The N 2 O flux are generally low, with most values ranging from –5 to 30 μg N m -2 h -1 , probably favoured by the low rainfall and soil mineral nitrogen levels during the evaluated period. Similarly magnitude to the soil under native grassland, CH 4 oxidation predominated in forested soils in the period of the experiment. The soil with two-year old eucalyptus plantation tended to emit more N 2 O than the four-year plantation. The harvest of acacia increased the soil N 2 O emission, likely due to the larger availability of mineral N in the soil for the nitrification and denitrification processes. With respect to CH 4 , the largest emission coincided with periods of higher soil temperature, which is coherent herewith increased of the biological activity, especially in areas with less vegetation cover. The contents of total organic carbon (TOC) and total nitrogen (TN) in soils with eucalyptus and acacia were not significantly different from those observed in native grassland soil for most layers. The low CH 4 and N 2 O emissions from forestry added to the carbon sequestration in the plant biomass and wood products suggests that the change of land use for forestation is an effective option for mitigating the GHG emissions and for increasing the carbon sequestration in areas such as the Pampa Gaúcho.

Sistemas silvipastoris (SSPs) apresentam potencial para amenizar o problema do aquecimento global, pelo sequestro de CO2 atmosférico, principalmente na biomassa vegetal. Entretanto, se faz necessário estudar nestas áreas os fluxos de metano (CH4) e óxido nitroso (N2O) do solo, para se ter uma melhor compreensão da dinâmica destes gases no sistema solo-atmosfera. Este estudo teve como objetivo principal avaliar os fluxos de N2O e CH4 em um solo sob implantação de um sistema silvipastoril com a espécie arbórea leguminosa nativa Parapiptadenia rigida em campo nativo do bioma Pampa e determinar um fator de emissão (FE) de N2O para esta consorciação. O experimento foi conduzido em um Argissolo Vermelho anteriormente utilizado com pastagem nativa no município de São Gabriel, RS, Brasil. Para isso, mudas de P. rigida forram plantadas em outubro de 2012 em delineamento experimental de blocos ao acaso, com parcelas subdivididas. Os tratamentos nas parcelas principais foram: T1: campo nativo (NG); T2: NG + P. rigida com arranjo espacial de 2 x 4 m; e T3: NG + P. rigida com arranjo espacial de linhas duplas 6 x (2 x 2) m. A subdivisão das parcelas (18 x 30 m) constituiu a presença ou ausência de adubação mineral anual (NPK) das forrageiras nativas.Os fluxos de gases de efeito estufa do solo foram coletados a cada quinze dias ou após eventos de fertilização, no decorrer do ano de 2014, através de câmaras estáticas, com seis repetições. As concentrações de N2O e CH4 foram determinadas por cromatografia gasosa. Concomitantemente a cada coleta dos gases foi coletado amostras de solo (0-5 cm) para análise do teor de N-mineral e monitoramento das variáveis climáticas. Os resultados foram submetidos à análise de variância e teste de Tukey para comparação das médias (P <0,10). As taxas de fluxo diário de CH4 e N2O permaneceram baixa durante o período avaliado, variando de -18,3 para 23,1 μg N2O_N m-2 h-1 e de -40 a 105 μg CH4_C m-2 h-1. A Fertilização mineral elevou a emissão acumulada (P <0,10) apenas para o N2O. Foram observados dois picos de emissão de N2O concomitantemente com o aumento do teor de nitrogênio mineral (NO3- e NH4 +) no solo proporcionado pela adubação mineral. Foi encontrado um FE de N2O de 0,26%, menor que o indicado pelo IPCC para a prática de adubação mineral de pastagens, o qual é de 1%. As maiores taxas de emissões diárias de CH4, por sua vez, coincidiram com aumentos na umidade e temperatura do solo. Assim, a introdução de árvores de P. rigida em campo nativo não alterou significativamente os fluxos de CH4 e N2O do solo, independentemente do espaçamento de plantio após dois anos de plantio das arvores. / Silvopastoral systems (SSPs) can mitigate global warming through atmospheric CO2 sequestration, mainly in plant biomass. However, few is known about their effect on nitrous oxide (N2O) and methane (CH4) fluxes in the soil. This study aimed to evaluate N2O and CH4 fluxes in a soil with native grassland system afforested with native species of the leguminous tree Parapiptadenia rigida in the Brazilian Pampa and determine an N2O emission factor for this intercropping. The experiment was carried out in an Acrisol previously used with native grassland in São Gabriel, RS, Brazil, forested in October 2012. The experiment had a randomized block design, with split plots. Treatments in the main plots were: T1: native grassland (NG); T2: NG + P. rigida with spatial arrangement of 2 x 4 m; and T3: NG + P. rigida with spatial arrangement of double lines 6 x (2 x 2) m. The split plots (18 x 30 m) constituted the presence or absence of annual mineral fertilizer (NPK) for the native forages. Soil greenhouse gases were taken every fortnight or after fertilization events for one year (2014) through static chambers, with six replicates. Concentrations of N2O and CH4 were determined by gas chromatography, concomitantly to the monitoring of soil (0-5 cm) for the analysis of N-mineral content and climate variables. The results were submitted to analysis of variance and Tukey test to compare means (P<0.10). Daily flux rates of CH4 and N2O remained low during the evaluated period, ranging from -18.3 to 23.1 μg N2O_N m-2 h-1 and from -40 to 105 μg CH4_C m-2 h-1. Mineral fertilization increased the cumulated emission (P < 0.10) only for N2O. Two peaks of N2O emission were observed concomitantly to the increase of mineral nitrogen concentration (NO3- and NH4+) in soil due to mineral fertilization. Was found an emission factor (EF) of 0.26%, smaller than that indicated for the practice of N fertilization on pastures by the IPCC which is 1%. The largest emissions rates of CH4, in turn, coincided with raises in soil moisture and temperature. Thus, the introduction of P. rigida trees in natural grassland did not altered significantly the soil fluxes of CH4 and N2O, independently of their arrangement, after two years from the tree plantation.

N-Nitrosamines and N-nitrosamides have been reported to be mutagenic. N-Nitrosamides are direct mutagens that need no activation to be mutagenic, whereas N-nitrosamines need to be enzymatically activated to exert their mutagenicity. Oxidative demethylation of nitrosamines is a commonly accepted activation mechanism. Another pathway of nitroso compounds, denitrosation, has recently been proposed. The mechanism of denitrosation, however, is still unknown. The purpose of this study was to use a photo -reaction model to explore the possible denitrosation mechanism of N-nitroso compounds. An N-nitrosamine, N-nitrosomorpholi ne (NMOR), and an N-nitrosamide, N-methyl-N'-nitrosoguanidine (MMNG), were irradiated with long-wavelength UV light in the presence of phosphate. Denitrosation of these nitroso compounds occurred, and free radicals were generated during the photolysis of N-nitroso compounds. The free radical from NMOR is carbon centered, and the free radical from MNNG is nitrogen centered. They have different responses to phosphate. A stable mutagen is formed during the photolysis of NMOR in the presence of phosphate. The formation of this stable mutagen is through a free-radical mechanism. MNNG appears to be inactivated in terms of mutagenicity by the photodenitrosation. Free radicals produced during the photolysis of NMOR and MNNG are mutagenic through a direct radical interaction mechanism. The results of this study indicate that the newly found pathway of N-nitroso compounds, denitrosation, may be related to a free-radical mechanism.

Aminophosphonic and related compounds were almost unknown 50 years ago, but today the literature data have considerably increased. Their negligible mammalian toxicity and their similarity with aminoacids confer on these compounds a top place as potential candidates for drugs. The discovery of numerous natural aminophosphonic derivatives endowed with biological properties useful to both medicinal and agricultural fields enhanced the infatuation for synthetic analogs and homologs. Intensive work has been performed towards alpha-aminophosphonic compounds, the direct analogs of natural alpha-aminoacids, disclosing versatile strategies, compatible both with molecular diversity and asymmetric synthesis. Less synthetic effort was devoted to the synthesis of higher homologs. Recent developments of the Diels-Alder reaction offer an asymmetric and convergent entry to various six-membered highly functionalizable key intermediates, compatible with molecular variety. As it is, the Diels-Alder (D-A) reaction should provide an original and versatile entry to beta-, gamma- and delta-aminophosphonic compounds, a challenging research area. As a direct consequence of the strategy, one of the two D-A partners (diene or dienophile) will act as vehicle for the phosphonate moiety. By contrast to its common use for the stabilization of alpha-negative charges, its implication in D-A reactions remains scarce. Indeed, the phosphonate moiety is not an efficient substituent susceptible to activate the D-A reaction; its use requires compensation by the activation of the other partner or by specific activation. Both synthetic organic and computational chemistry will furnish information to propose a fine understanding of the key D-A steps, in view to optimize the achievement of the corresponding cycloadducts. These cycloadducts will be considered as synth-/chirons for the synthesis of aminophosphonic compounds.

Dietary nitrite intake has been implicated in numerous gastrointestinal cancers in humans due to the formation of a group of carcinogens called N-nitroso compounds. The need to estimate their intake is vital in establishing at risk population and to monitor and perhaps one day manage their dietary intake. This is the first study to estimate nitrate and nitrite in selected vegetables, cured and fresh meat in Australian food supply using ion-paired reversed-phased HPLC. Nitrite content in meat products analysed ranged from 0 to 83.9 mg/kg in medallion beef and Frankfurt, respectively; nitrate content ranged from 18.7 mg/kg in minced beef to 142.5 mg/kg in salami. The nitrite content was below the maximum limit set by the Food Standards Australia and New Zealand. Nitrate content in selected vegetables ranged from 123 to 4850 mg/kg in Iceberg lettuce and English spinach, respectively; only minimal nitrite at 20 mg/kg was present in Gai choy, which was most likely due to bacterial contamination during storage. Based on the food consumption pattern of Australians, the dietary nitrite and nitrate intake from bacon were 1.51 and 3.42 mg per capita per day, which was below the Adequate Daily Intake set by the European Union Scientific Committee for food in 1995. Taking into considerations of oral nitrate reduction to nitrite and the endogenous nitrate formation, the upper extreme of dietary nitrite and nitrate intake in Australians were 44 and 2.4 times over the ADI, respectively. However, this does not take into effect of other dietary promoters and inhibitors. Eighteen healthy human volunteers were put on a low nitrate, nitrite and antioxidant diet for three days during which they were fed one serving of cured meat with and without 500 mg of vitamin C. Using GC-MS, N-nitrosodimethylamine was not detected in the urine before or after vitamin C supplementation, suggested that a diet low on nitrate and nitrite cannot produce NDMA and thus may reduce the risk of developing gastrointestinal cancers. Different extraction methods and combination of herbs and spices were demonstrated in vitro to show inhibition against B. cereus, Escherichia coli, Listeria monocytogenes, Salmonella Enteritidis and Staphylococcus aureus. In addition, autoclaved turmeric powder at 0.3 % (w/v), hot water extracted turmeric with ginger at 0.5 % and rosemary at 1.0 % showed growth inhibition against Clostridium sporogenes, which was used as a surrogate for Clostridium botulinum. The use of these combinations of herbs and spices may replace or at least reduce the use of nitrite as a preservative in cured meat products to prevent botulism and reduce dietary nitrite intake.

Dietary nitrite intake has been implicated in numerous gastrointestinal cancers in humans due to the formation of a group of carcinogens called N-nitroso compounds. The need to estimate their intake is vital in establishing at risk population and to monitor and perhaps one day manage their dietary intake. This is the first study to estimate nitrate and nitrite in selected vegetables, cured and fresh meat in Australian food supply using ion-paired reversed-phased HPLC. Nitrite content in meat products analysed ranged from 0 to 83.9 mg/kg in medallion beef and Frankfurt, respectively; nitrate content ranged from 18.7 mg/kg in minced beef to 142.5 mg/kg in salami. The nitrite content was below the maximum limit set by the Food Standards Australia and New Zealand. Nitrate content in selected vegetables ranged from 123 to 4850 mg/kg in Iceberg lettuce and English spinach, respectively; only minimal nitrite at 20 mg/kg was present in Gai choy, which was most likely due to bacterial contamination during storage. Based on the food consumption pattern of Australians, the dietary nitrite and nitrate intake from bacon were 1.51 and 3.42 mg per capita per day, which was below the Adequate Daily Intake set by the European Union Scientific Committee for food in 1995. Taking into considerations of oral nitrate reduction to nitrite and the endogenous nitrate formation, the upper extreme of dietary nitrite and nitrate intake in Australians were 44 and 2.4 times over the ADI, respectively. However, this does not take into effect of other dietary promoters and inhibitors. Eighteen healthy human volunteers were put on a low nitrate, nitrite and antioxidant diet for three days during which they were fed one serving of cured meat with and without 500 mg of vitamin C. Using GC-MS, N-nitrosodimethylamine was not detected in the urine before or after vitamin C supplementation, suggested that a diet low on nitrate and nitrite cannot produce NDMA and thus may reduce the risk of developing gastrointestinal cancers. Different extraction methods and combination of herbs and spices were demonstrated in vitro to show inhibition against B. cereus, Escherichia coli, Listeria monocytogenes, Salmonella Enteritidis and Staphylococcus aureus. In addition, autoclaved turmeric powder at 0.3 % (w/v), hot water extracted turmeric with ginger at 0.5 % and rosemary at 1.0 % showed growth inhibition against Clostridium sporogenes, which was used as a surrogate for Clostridium botulinum. The use of these combinations of herbs and spices may replace or at least reduce the use of nitrite as a preservative in cured meat products to prevent botulism and reduce dietary nitrite intake.