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| Registros recuperados: 113 | |
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| Lira Casas, Raymundo. |
| Las nuevas líneas de investigación en nutrición de rumiantes están buscando diseñar productos con liberación prolongada de urea dentro del rumen. El objetivo de esta investigación fue desarrollar y evaluar microcápsulas que liberen urea en el líquido ruminal. Métodos: Las microcápsulas fueron preparadas por el método de emulsión y evaporación de solvente, como primer paso se preparo el acarreador poroso, después se preparo la fase orgánica con Eudragit RS 100 y por último se preparo la fase acuosa en donde fue agregada la fase orgánica. Las microcápsulas se identificaron mediante microscopia electrónica de barrido, determinando el tamaño y la morfología. Se evaluó la encapsulación de la urea, la flotabilidad de las microcápsulas y la liberación de N... |
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Palavras-chave: Urea; Microcápsulas; Lenta liberación; Rumiante; Microcapsules; Slow release; Ruminant; Maestría; Ganadería. |
| Ano: 2011 |
URL: http://hdl.handle.net/10521/448 |
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| Loyo García, Alejandro. |
| En el estado de Veracruz, Méx. existen numerosas plantaciones de lima Persa injertado sobre limón Volkameriano (Citrus volkameriana Ten. y Pasq.) que es un portainjerto vigoroso, por ello, el crecimiento de los árboles se controla para aumentar su eficiencia, mejorar la producción y producir fruta en épocas de temporada baja para aprovechar los altos precios de venta en el mercado nacional. El objetivo del presente trabajo fue incrementar la floración en brotes de otoño en los meses de octubre y noviembre mediante la aplicación de podas, un retardante del crecimiento, fertilizaciones foliares nitrogenadas y rayado de ramas. El estudio se hizo en árboles de lima Persa de siete años de edad. Dos experimentos fueron realizados, en el primero, se aplicó en... |
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Palavras-chave: Citrus latifolia Tan.; Brotes de otoño; Intensidad de floración; Nitrato de calcio; Urea; Maestría; Fruticultura. |
| Ano: 2010 |
URL: http://hdl.handle.net/10521/172 |
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| Loyo García, Alejandro. |
| En el estado de Veracruz, Méx. existen numerosas plantaciones de lima Persa injertado sobre limón Volkameriano (Citrus volkameriana Ten. y Pasq.) que es un portainjerto vigoroso, por ello, el crecimiento de los árboles se controla para aumentar su eficiencia, mejorar la producción y producir fruta en épocas de temporada baja para aprovechar los altos precios de venta en el mercado nacional. El objetivo del presente trabajo fue incrementar la floración en brotes de otoño en los meses de octubre y noviembre mediante la aplicación de podas, un retardante del crecimiento, fertilizaciones foliares nitrogenadas y rayado de ramas. El estudio se hizo en árboles de lima Persa de siete años de edad. Dos experimentos fueron realizados, en el primero, se aplicó en... |
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Palavras-chave: Citrus latifolia Tan.; Brotes de otoño; Intensidad de floración; Nitrato de calcio; Urea; Maestría; Fruticultura. |
| Ano: 2010 |
URL: http://hdl.handle.net/10521/172 |
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| Lira Casas, Raymundo. |
| Las nuevas líneas de investigación en nutrición de rumiantes están buscando diseñar productos con liberación prolongada de urea dentro del rumen. El objetivo de esta investigación fue desarrollar y evaluar microcápsulas que liberen urea en el líquido ruminal. Métodos: Las microcápsulas fueron preparadas por el método de emulsión y evaporación de solvente, como primer paso se preparo el acarreador poroso, después se preparo la fase orgánica con Eudragit RS 100 y por último se preparo la fase acuosa en donde fue agregada la fase orgánica. Las microcápsulas se identificaron mediante microscopia electrónica de barrido, determinando el tamaño y la morfología. Se evaluó la encapsulación de la urea, la flotabilidad de las microcápsulas y la liberación de N... |
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Palavras-chave: Urea; Microcápsulas; Lenta liberación; Rumiante; Microcapsules; Slow release; Ruminant; Maestría; Ganadería. |
| Ano: 2011 |
URL: http://hdl.handle.net/10521/448 |
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| Hernández,Christian A; Sandoval,Norma; Mallerman,Julieta; García-Pérez,José Antonio; Farnet,Anne-Marie; Perraud-Gaime,Isabelle; Alarcón,Enrique. |
| Background Ethanol has been pointed out as a laccase inducer. However, there are controversial reports about its efficiency with some fungi. In this study, we hypothesized that ethanol laccase induced in Pycnoporus sanguineus depends on nitrogen nutriment conditions. To prove this, we assessed laccase production in submerged cultures of P. sanguineus, with different nitrogen concentrations and with, or without ethanol added in a factorial designed experiment. Results In order to analyze the effects of factors on the response variables, a factorial ANOVA, and response-surface models were performed. It was found that the nitrogen source was the main factor that affected laccase production in P. sanguineus. The treatments with yeast extract (2 g/L) and... |
| Tipo: Journal article |
Palavras-chave: Enzyme production; Fungal metabolism; Phenoloxidases; Urea; Yeast extract. |
| Ano: 2015 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582015000400012 |
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| Coelho,Eugênio F.; Andrade Neto,Torquato M. de; Barros,Damiana L.. |
| The Fertigation is the combined application of water and nutrients to a crop. It can be adapted to all types of agricultural crops. The objective of this study was to evaluate the effect of urea concentration in irrigation water on electrical conductivity of the soil solution and saturation extract along the first cycle of banana cv. Terra Maranhão. The experiment followed a completely randomized design with six treatments and ten replications. Treatments regarded for using three urea concentrations (1.0; 2.5 and 4.0 g L-1) in irrigation water applied by two micro irrigation systems (microsprinkler and drip). Results showed that there was a linear elevation of electrical conductivity of saturation extract and soil solution with the increase on... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Urea; Salinity; Fertirrigation. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162014000600007 |
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| Pôrto,Mônica L; Alves,Jailson do C; Souza,Adailson P de; Araújo,Raunira da C; Arruda,Jandeilson A de. |
| Lettuce is one of the leading vegetables in Brazil. However, studies concerning its fertilization for the Northeastern region of the country are still scarce. This work was carried out to evaluate the effects of mineral Nitrogen supply and organic fertilization on the production and nitrate accumulation in lettuce, cultivar Elba, in the semi-arid zone of Paraíba, Brazil. A randomized block design, with four replications, was used to test five doses of cattle manure (30; 60; 90; 120, and 150 t ha-1), five doses of N supplied as urea (30; 60; 90; 120, and 150 kg ha-1), and a control without fertilization. Along with mineral N, the other nutrients were also supplied using mineral sources. No additional nutrients were supplied where organic fertilization was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lactuca sativa L.; Lettuce; Cattle manure; Urea; Yield. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362008000200019 |
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| Person, Jeannine; Lamers, A; Le Roux, Annick; Severe, Armelle; Boeuf, Gilles; Mayer Gostan, N. |
| Turbot juveniles were exposed to four ammonia concentrations [0.17 (L), 0.34 (M), 0.73 (MH) and 0.88 (H) mgl(-1) NH3-N] for different exposure durations (28 days minimum to 84 days). Their physiological status and growth performances were compared to a control group [0.004 (C) mgl(-1) NH3-N]. No growth was observed in the H group, and by day 57, mass increase in the MH group was only 15% of that in group C. During the first month growth in the L group was similar to that in control group while it was lower (33%) in the M group; afterwards the L and M groups had a similar growth (half that of controls). Accumulation of total ammonia nitrogen (TA-N) in plasma was dependent on ambient ammonia concentrations. Plasma urea levels in ammonia-exposed fish were... |
| Tipo: Text |
Palavras-chave: Urea; Total ammonia nitrogen; Scophthalmus maximus; Ion regulation; Cortisol; Chronic toxicity. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-618.pdf |
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| Collos, Y; Vaquer, A; Laabir, M; Abadie, Eric; Laugier, Thierry; Pastoureaud, Annie; Souchu, Philippe. |
| A monitoring program with a weekly sampling frequency over a 15-month period indicates that urea concentrations above a certain threshold level may trigger the blooms of Alexandrium catenella in Thau lagoon. However, urea concentrations were also sometimes related to ammonium and dissolved organic nitrogen concentrations, indicating that the role of urea may not be a direct one. An original approach is used to assess the relative contribution of several nitrogen sources (nitrate, nitrite, ammonium, urea) to growth of A. catenella by comparing nitrogen uptake rates to nitrogen-based growth rates estimated from dilution experiments during four blooms over a 4-year period (2001-2004) in Thau lagoon. Nitrate and nitrite contributed 0.1-14% and 0.1-5%... |
| Tipo: Text |
Palavras-chave: Uptake kinetics; Ammonium; Urea; Growth; Nitrogen; HAB; Alexandrium catenella. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-6454.pdf |
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| García-portela, Maria; Reguera, Beatriz; Gago, Jesus; Le Gac, Mickael; Rodríguez, Francisco. |
| Dinoflagellate species of Dinophysis are obligate mixotrophs that require light, nutrients, and prey for sustained growth. Information about their nitrogenous nutrient preferences and their uptake kinetics are scarce. This study aimed to determine the preferred nitrogen sources in cultures of D. acuminata and D. acuta strains from the Galician Rías Baixas (NW Spain) and to compare their uptake kinetics. Well-fed versus starved cultures of D. acuminata and D. acuta were supplied with N15 labeled inorganic (nitrate, ammonium) and organic (urea) nutrients. Both species showed a preference for ammonium and urea whereas uptake of nitrate was negligible. Uptake rates by well-fed cells of D. acuminata and D. acuta were 200% and 50% higher, respectively, than by... |
| Tipo: Text |
Palavras-chave: Dinophysis; Nitrate; Ammonium; Urea; Uptake rates; N-15 incubations; Antibiotic treatment. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00606/71770/70250.pdf |
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| Longo, Sébastien; Sibat, Manoella; Taiana Darius, Hélène; Hess, Philipp; Chinain, Mireille. |
| Ciguatera poisoning is a foodborne disease caused by the consumption of seafood contaminated with ciguatoxins (CTXs) produced by dinoflagellates in the genera Gambierdiscus and Fukuyoa. Ciguatera outbreaks are expected to increase worldwide with global change, in particular as a function of its main drivers, including changes in sea surface temperature, acidification, and coastal eutrophication. In French Polynesia, G. polynesiensis is regarded as the dominant source of CTXs entering the food web. The effects of pH (8.4, 8.2, and 7.9), Nitrogen:Phosphorus ratios (24N:1P vs. 48N:1P), and nitrogen source (nitrates vs. urea) on growth rate, biomass, CTX levels, and profiles were examined in four clones of G. polynesiensis at different culture age (D10, D21,... |
| Tipo: Text |
Palavras-chave: Gambierdiscus polynesiensis; French Polynesia; Ciguatera; Ciguatoxins; LC-MS; MS; Toxin profile; Nitrate; Urea; Culture medium acidification. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00662/77382/78981.pdf |
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| Jauzein, Cecile; Loureiro, Sofia; Garces, Esther; Collos, Yves. |
| Short-term experiments were carried out to investigate whether interactions between ammonium (NH4+) and urea uptake regulate the total nitrogen assimilation of the toxic dinoflagellate Alexandrium catenella. To test for strain variability, 5 strains of A. catenella from the NW Mediterranean were used: 3 strains from the Thau lagoon (southern France) and 2 strains from the Catalonia basin (Spain). For each strain, the uptake rate of 1 nutrient (NH4+ or urea) at a reference concentration (10 mu gatN l(-1)) was measured as a function of the increasing concentration of the other nutrient (0 to 10 mu gatN l(-1)). Simultaneous N uptake rates of the distinct nitrogen sources were obtained from N-15-NH4+ and N-15-urea incorporation measurements. A strong... |
| Tipo: Text |
Palavras-chave: Strain variability; Interactions; Urea; Ammonium; Alexandrium catenella. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6432.pdf |
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| Loureiro, Sofia; Jauzein, Cecile; Garces, Esther; Collos, Yves; Camp, Jordi; Vaque, Dolors. |
| The influence of organic nutrients on the evolution of Pseudo-nitzschia delicatissima cultures was investigated in an enrichment experiment with high-molecular-weight dissolved organic matter (HMWDOM) and in an uptake assay with N-15-ammonium and N-15-urea. HMWDOM was extracted from seawater collected at a nearby shore station during the decline of a diatom bloom. Four incubations were prepared: L1/5+DOM (P. delicatissima grown in L1 growth medium with 1/5 of the nitrate concentration of standard L1), (L1-N)+DOM (L1 without nitrate, i.e. nitrogen-deficient treatment), L1-DOM (control culture without added DOM) and BV+DOM (bacterial and viral control, free of microalgae). Incubations were carried out for 10 days. Chlorophyll a concentrations differed after... |
| Tipo: Text |
Palavras-chave: Harmful Algal Blooms (HABs); Nitrogen Uptake; Urea; Dissolved Organic Matter (DOM). |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6438.pdf |
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| Registros recuperados: 113 | |
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