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Search Results: 1 - 10 of 6232 matches for " Deborah Guerra;Urquiaga "
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Fixa??o biológica e transferência de nitrogênio por leguminosas em pomar organico de mangueira e gravioleira
Paulino, Gleicia Miranda;Alves, Bruno José Rodrigues;Barroso, Deborah Guerra;Urquiaga, Segundo;Espindola, José Antonio Azevedo;
Pesquisa Agropecuária Brasileira , 2009, DOI: 10.1590/S0100-204X2009001200006
Abstract: the objective of this work was to evaluate the biological nitrogen fixation (bnf) and the n transfer derived from bnf of the legume species - gliricidia sepium (gliricidia), crotalaria juncea (sunnhemp) and cajanus cajan (pigeon pea) - for an intercropped organic orchard with mango and soursop, through the 15n natural abundance method. the following intercropping systems were evaluated: mango and soursop with gliricidia; mango and soursop with sunnhemp; mango and soursop with pigeon pea; and mango and soursop as control. gliricidia showed the highest bnf potential (80%) , followed by sunnhemp (64.5%) and pigeon pea (45%). after two sunnhemp prunes, 149.5 kg ha-1 of n per year were supplied, with 96.5 kg derived from bnf. after three annual prunes, gliricidia supplied 56.4 and 80.3 kg ha-1 of n per year, with 45 and 64 kg derived from bnf, in two consecutive years. the quantity of n supplied to the system was higher than the mango and soursop requirements. variations in the natural abundance of 15n were found only in soursop leaves. gliricidia and sunnhemp were prominent in n transfer, with approximately 22.5 and 40% respectively. green manuring using gliricidia permits fractioning of the n supply, which is an advantage in n obtention by the fruit trees.
Efeito residual da aduba??o verde no rendimento de brócolo (Brassica oleraceae L. var. Italica) cultivado em sucess?o ao milho (Zea mays L.)
Perin, Adriano;Santos, Ricardo Henrique Silva;Urquiaga, Segundo;Guerra, José Guilherme Marinho;Cecon, Paulo Roberto;
Ciência Rural , 2004, DOI: 10.1590/S0103-84782004000600011
Abstract: the objectives of this work were to evaluate the residual effects of the single and intercropped sunnhemp (crotalaria juncea) and millet (pennisetum americanum) as green manures on nitrogen transfer and yield of broccoli crop in succession to corn in absence and presence of fertilization of 150kg ha-1 of n. the experiment is a randomized block in split plot design and four replicates. the plot treatments were the previous cultivation of sunnhemp, millet, sunnhemp + millet and spontaneous vegetation. on subplots, the treatments were 150kg ha-1 of n and control (absence of n-fertilizer on broccoli). the succession involved the cultivation of the green manures (september, 26th, 2001 to december, 03th, 2001), followed by corn crop (december, 04th, 2001 to may, 28th, 2002) and broccoli hybrid big sur (june, 05th, 2002 to august, 10th, 2002) in zero tillage on the corn residues. it was not detected residual effect of the green manures on the diameter, dry weight of flower buds and dry mass yield of broccoli, either in the absence or presence of n-fertilizer. the presence of the single sunnhemp on crop rotation elevated the content and accumulation of n in the leaves and flower buds of broccoli, either in the absence or presence of 150kg ha-1 of n. in the intercrop sunnhemp and millet, the presence of the leguminous elevated the content and accumulation of n in inflorescences, comparatively to the single millet. in the plots without n-fertilizer and cultivated with sunnhemp the diameter of broccoli buds was similar to spontaneous vegetation + 150kg ha-1 of n. however, the yield of broccoli and the content and accumulation of n in buds were greater after spontaneous vegetation + 150kg ha-1 of n than after green manures without n-fertilizer. the utilization the n from biological fixation by broccoli inflorescences was 9.15% when single and 8.48% when intercropped.
Produ??o de fitomassa, acúmulo de nutrientes e fixa??o biológica de nitrogênio por adubos verdes em cultivo isolado e consorciado
Perin, Adriano;Santos, Ricardo Henrique Silva;Urquiaga, Segundo;Guerra, José Guilherme Marinho;Cecon, Paulo Roberto;
Pesquisa Agropecuária Brasileira , 2004, DOI: 10.1590/S0100-204X2004000100005
Abstract: the objective of this work was to evaluate the effects of sole and intercropping systems of the summer green manures sunnhemp (crotalaria juncea) and millet (pennisetum americanum) in phytomass yield, content and accumulation of nutrients and biological nitrogen fixation (bnf). the experimental design was a randomized complete block with four replicates, and treatments consisted of green manures sunnhemp, millet, sunnhemp + millet and spontaneous vegetation. the sunnhemp stood out in the phytomass yield, being 108% greater than the spontaneous vegetation and 31% superior to millet. in the sunnhemp + millet intercropping, the leguminous contributed with 65% of the total dry matter. the presence of sunnhemp resulted in larger contents of n and ca, while millet and the spontaneous vegetation showed larger content of potassium. the accumulation of p and mg was strongly influenced by the phytomass yield, reaching high values in the presence of sunnhemp, while the accumulation of n and ca was a result of the largest contents as well as the largest phytomass yield in the treatments with the leguminous. the bnf was 61% in the intercropping and 57% in sole cropping, incorporating to soil via bnf 89 and 173 kg/ha of n, respectively, being an excellent strategy for increasing soil nitrogen.
Crescimento, acúmulo de nutrientes e fixa o biológica de nitrogênio de Flemingia macrophylla Growth, nutrient accumulation and biological nitrogen fixation of Flemingia macrophylla
Alexandre Porto Salmi,Ilzo Artur Moreira Risso,José Guilherme Marinho Guerra,Segundo Urquiaga
Revista Ceres , 2013,
Abstract: Flemingia macrophylla é uma leguminosa arbustiva asiática, pouco conhecida no Brasil. Este trabalho objetivou avaliar a produ o de massa seca, o acúmulo de nutrientes e a fixa o biológica de nitrogênio (N2) de flemingia. Conduziram-se dois experimentos de campo, entre dezembro de 2006 e dezembro de 2007, em Seropédica, RJ, e em Avelar, RJ. O delineamento experimental utilizado em ambos os experimentos foi de blocos casualizados, com quatro repeti es, e os tratamentos foram as diferentes épocas de amostragens. A área foliar, a produ o de matéria seca e o acúmulo de nutrientes da parte aérea foram determinados em 12 coletas mensais. A contribui o da fixa o biológica de N2 foi estimada pelo método da abundancia natural de 15N. A massa seca da parte aérea atingiu 4,0 Mg ha-1 em Seropédica e 2,3 Mg ha-1 em Avelar, aos 360 dias após transplante (DAT). O menor crescimento em Avelar foi associado ao inverno mais frio e seco, em rela o a Seropédica. A taxa de crescimento da cultura atingiu valor máximo aos 165 DAT, na primeira flora o. O acúmulo de N, P, K, Ca e Mg na parte aérea foi de, respectivamente, 74, 5, 33, 25 e 8 kg ha-1 aos 360 DAT. A percentagem de N, proveniente da fixa o biológica de N2 em flemingia, foi de aproximadamente 76%, o que propiciou 57 kg ha-1 de N oriundo da fixa o biológica, na parte aérea, aos 360 DAT. Os resultados indicam que flemingia é uma espécie que pode contribuir com quantidades significativas de biomassa e nutrientes, especialmente N, sendo promissora para uso como adubo verde e em cultivos em aleias, em sistemas de produ o. Flemingia macrophylla is an Asian shrub legume scarcely known in Brazil. The objective of this work was to evaluate the growth, nutrient accumulation and biological N2 fixation of flemingia. Two field experiments were conducted from December 2006 to December 2007, in Seropédica and in Avelar, Rio de Janeiro State. Both experiments were arranged in a completely randomized block design with four repetitions, and the treatments consisted of the different sampling times. Leaf area, biomass and nutrient accumulation in leaves and branches were measured in twelve monthly samplings. Biological N2 fixation was estimated by the natural abundance of 15N. Shoot biomass yield reached 4.0 Mg ha-1 in Seropédica and 2.3 Mg ha 1 in Avelar at 360 days after transplanting (DAT). The lower growth in Avelar was associated with the colder and drier winter than in Seropédica. The highest crop growth rate was observed at 165 DAT, at the first flowering. Accumulation of N, P, K, Ca and Mg in shoots was, respectively, 7
Produ o de fitomassa, acúmulo de nutrientes e fixa o biológica de nitrogênio por adubos verdes em cultivo isolado e consorciado
Perin Adriano,Santos Ricardo Henrique Silva,Urquiaga Segundo,Guerra José Guilherme Marinho
Pesquisa Agropecuária Brasileira , 2004,
Abstract: O objetivo deste trabalho foi avaliar os efeitos dos cultivos isolado e consorciado dos adubos verdes de ver o crotalária (Crotalaria juncea) e milheto (Pennisetum americanum) na produ o de fitomassa, nos teores e acúmulo de nutrientes e na fixa o biológica de nitrogênio (FBN). O delineamento experimental adotado foi blocos ao acaso, com quatro repeti es, em que os tratamentos constaram dos adubos verdes crotalária, milheto, crotalária + milheto e vegeta o espontanea. A crotalária apresentou maior produ o de fitomassa, que foi 108% maior que a da vegeta o espontanea e 31% superior a do milheto. No consórcio crotalária + milheto, a leguminosa contribuiu com 65% da massa de matéria seca total. A presen a da crotalária resultou em maiores teores de N e Ca, enquanto o milheto e as ervas espontaneas apresentaram maiores teores de potássio. O acúmulo de P e Mg foi fortemente influenciado pela produ o de fitomassa, atingindo valores elevados com a presen a da crotalária, ao passo que o acúmulo de N e Ca resultou tanto dos maiores teores quanto da maior produ o de fitomassa nos tratamentos com a leguminosa. A FBN foi 61% na leguminosa quando consorciada e 57% quando isolada, incorporando ao solo via FBN 89 e 173 kg/ha de N, respectivamente, constituindo-se excelente estratégia de incremento de N ao solo.
Efeito residual da aduba o verde no rendimento de brócolo (Brassica oleraceae L. var. Italica) cultivado em sucess o ao milho (Zea mays L.)
Perin Adriano,Santos Ricardo Henrique Silva,Urquiaga Segundo,Guerra José Guilherme Marinho
Ciência Rural , 2004,
Abstract: Os objetivos deste trabalho foram avaliar o efeito residual do cultivo isolado e consorciado dos adubos verdes crotalária (Crotalaria juncea) e milheto (Pennisetum americanum) sobre a transferência de Nitrogênio (N) e produ o de brócolo, em sucess o ao milho, na ausência e presen a da aduba o de 150kg ha-1 de N. O delineamento experimental foi de blocos ao acaso com parcelas subdivididas e quatro repeti es. Os tratamentos da parcela constaram do pré-cultivo dos adubos verdes crotalária, milheto, crotalária + milheto e vegeta o espontanea. Na subparcela, os tratamentos foram 150kg ha-1 de N e testemunha (ausência de N-fertilizante no brócolo). A sucess o envolveu o cultivo dos adubos verdes (26/09/2001 a 03/12/2001), seguido pelo cultivo de milho (04/12/2001 a 28/05/2002) e brócolo híbrido Big Sur (05/06/2002 10/08/2002), em plantio direto, sobre os resíduos do milho. N o foi detectado efeito residual dos adubos verdes sobre o diametro, peso da matéria seca das inflorescências e produ o de matéria seca do brócolo, tanto na ausência quanto na presen a de N-fertilizante. A crotalária isolada em pré-cultivo elevou o teor e acúmulo de N nas folhas e inflorescência de brócolo, na ausência ou presen a de 150kg ha-1 de N. No consórcio crotalária + milheto, a presen a da leguminosa elevou o teor e acúmulo de N, na inflorescência, comparativamente ao milheto isolado. O diametro das inflorescências do brócolo, nas parcelas sem N-fertilizante precedidas da crotalária, foi similar à vegeta o espontanea + 150kg ha-1 de N. Entretanto, a produ o de brócolo e o teor e acúmulo de N, nas inflorescências, foram maiores após vegeta o espontanea + 150kg ha-1 de N do que após adubos verdes sem N-fertilizante. O aproveitamento do N proveniente da fixa o biológica pela inflorescência de brócolo foi 9,15%, quando isolada e 8,48%, quando consorciada.
Decomposi??o e libera??o de nutrientes acumulados em leguminosas herbáceas perenes consorciadas com bananeira
Espindola, José Antonio Azevedo;Guerra, José Guilherme Marinho;Almeida, Dejair Lopes de;Teixeira, Marcelo Grandi;Urquiaga, Segundo;
Revista Brasileira de Ciência do Solo , 2006, DOI: 10.1590/S0100-06832006000200012
Abstract: evaluating the decomposition of cover crop residues added to the soil allows improving the comprehension of appropriate nutrient supply for commercial crops. this study was carried out under field conditions aiming to evaluate the decomposition and nutrient release from the shoots of perennial herbaceous legumes. the treatments were green cover crops intercropped with banana: groundnut (arachis pintoi krapov. & w.c. gregory.), tropical kudzu (pueraria phaseoloides (roxb.) benth.), siratro (macroptilium atropurpureum (sessé & moc. ex dc.) urb.) and spontaneous vegetation (mainly panicum maximum jacq.). these species were cut during the dry (april 1997) and rainy seasons (january 1998). aboveground cover crop samples were placed in litterbags, which were distributed on the plots soil surface. dry matter decomposition and nutrient release were monitored through collection of litterbags at 5, 10, 15, 30, 60, 90, 120 and 150 days after cutting the cover crops. dry matter decomposition of groundnut was the fastest and the spontaneous vegetation was the slowest. the decomposition constants decreased and residue half-lives increased during the dry season. there was a faster release of n, ca and mg in the legumes, while spontaneous vegetation presented similar results for p. among the chemical variables under study, the cellulose and hemicellulose contents were correlated with dry matter loss. n release was correlated with c and hemicellulose contents. results indicate the potential of perennial herbaceous legumes for nutrient release, particularly in the case of tropical kudzu and siratro.
Acúmulo e libera??o de P, K, Ca e Mg em crotalária e milheto solteiros e consorciados
Perin, Adriano;Santos, Ricardo Henrique Silva;Caballero, Segundo Sacramento Urquiaga;Guerra, José Guilherme Marinho;Gusm?o, Luiz Ant?nio;
Revista Ceres , 2010, DOI: 10.1590/S0034-737X2010000200020
Abstract: the characteristics of legumes and grasses used as cover crops are well known, but the release rate of nutrients associated with plant biomass becomes available to crops is still little studied. the objective of this work was to quantify the nutrient accumulation and release of sunnhemp and millet in monocrop and intercropping. the experimental design was a randomized complete block with four replicates. the treatments were sunnhemp, millet, sunnhemp + millet and weeds. the accumulation of p and mg was strongly influenced by the dry matter yield, reaching high values in the presence of sunnhemp, while the accumulation of ca was a result of both the high content and the high dry mater yield in the treatments with the leguminous. the rate of nutrient release showed similar dynamics, with two distinct phases: the first with higher release, in first the 15 days and the second, slowest, from this phase. the intercropping did not affect the release rates of k, ca and mg, while the presence of sunnhemp enhanced the release of n. sunnhemp residues showed a p release higher than weeds, where the sunnhemp t 1/2 was of 11 days and the weeds of 17 days. ca was released from de mass in a slower rate than the other nutrients, whereas the mg was released more quickly. weeds and millet show a high potential of k recycling and sunnhemp has a high potential of ca and mg recycling.
Sunnhemp and millet as green manure for tropical maize production
Perin, Adriano;Santos, Ricardo Henrique Silva;Urquiaga, Segundo Sacramento;Cecon, Paulo Roberto;Guerra, José Guilherme Marinho;Freitas, Gilberto Bernardo de;
Scientia Agricola , 2006, DOI: 10.1590/S0103-90162006000500006
Abstract: commonly n release from legume residues is rapid in the tropics. legume mixtures with grasses can result in slower nutrient release from residues, better matching the n requirements of the following crop. the objectives of this study were to evaluate the effects of the green manures sunnhemp (crotalaria juncea) and millet (pennisetum glaucum), alone or mixed, on the performance of a subsequent maize crop with and without the application of n-fertilizer. the experiment consisted of four randomized blocks, with split plots. the plot treatments consisted of previous cultivation of sunnhemp, millet, mixed sunnhemp+millet and weeds. the subplot treatments were 90 kg n ha-1 and absence of n-fertilizer. substantial amounts of biological nitrogen fixation (bnf) nitrogen were present in above ground parts of sunnhemp alone (173 kg ha-1) and mixed with millet (89 kg ha-1). decay rates showed that half of the n was released 15 and 22 days from sunnhemp and sunnhemp+millet residues, respectively. the difference was attributed to temporary immobilization due to the higher c/n ratio of sunnhemp+millet. the preceding sunnhemp+millet treatment resulted in a larger maize yield than sunnhemp alone, when no n-fertilizer was applied. this effect was not observed when n-fertilizer was added. this effect may be due to a more timely n release, compared to sunnhemp and millet alone, when available n is required for maize. nitrogen budgets showed that 15% and 10% in maize grain n was recovered from bnf for sunnhemp alone and sunnhemp+millet respectively. the recovery of n-bnf by maize was 65% higher after sunnhemp+millet than after sunnhemp monocrop.
The genetics of lupus: a functional perspective
Sandra G Guerra, Timothy J Vyse, Deborah S Cunninghame Graham
Arthritis Research & Therapy , 2012, DOI: 10.1186/ar3844
Abstract: Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease characterized by hyperactive T and B cells, auto-antibody production, and immune complex(IC) deposition [1]. SLE has a prevalence of approximately 1 in 2,500 in European populations [2] and is more frequent in those of non-European ancestry. SLE affects predominantly women (the female-to-male ratio is 9:1) of child-bearing age and is characterized by variable clinical features, including malar rash, glomerulonephritis, arthritis, and neuropsychiatric disease [3]. Although the exact etiology of lupus is not fully understood, a strong genetic link has been identified through the use of association and family studies. The heritability of SLE is approximately 66%; the rates of concordance are 24% to 56% in monozygotic twins and 2% to 4% in dizygotic twins [4,5].To date, genome-wide association studies (GWASs) have identified more than 30 associated loci. In Table 1, we show the variants that have reached genome-wide significance (1.0 × 10?8) in one or more GWASs, a metaanalysis, or replication studies. We have also included the Fcγ locus, because it contains multiple associated variants, including a confirmed copy number variation (CNV) in SLE. However, these loci account for less than 10% of the genetic heritability [6].GWASs in SLE have been useful tools for expanding the genetic understanding of SLE by identifying new loci and replicating previously associated loci. In this review, we categorize these risk loci into a number of pathways on the basis of the current understanding of the potential role for the locus in SLE. We note that the clinical heterogeneity of SLE is mirrored by the diversity of the pathways reported to contain the associated loci from the genetic studies, apoptosis, innate immune response, ubiquitination, and phagocytosis (Table 1). Therefore, this review aims to highlight the known function(s) of the associated loci and to indicate where further functional studies are neede
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