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Determinación de la Curva de Dilución de Nitrógeno en Diferentes Fases Fenológicas del Girasol
de Caram,Gladis A; Angeloni,Patricia; Prause,Juan;
Agricultura Técnica , 2007, DOI: 10.4067/S0365-28072007000200009
Abstract: the concentration of nitrogen which allows a crop to reach its maximum growth rate is called critical concentration. this concentration varies according to the aerial biomass considered, as when this increases, there is a dilution effect of the nitrogen in the plant. the aim of this work was to characterize the nutritional state of foliar nitrogen in two sunflower hybrids (helianthus annuus l.), at different phenological phases, using the nitrogen dilution curve in total aerial dry matter. the treatment was applied to two hybrids, guarani dc and dksol 4040, sown in four furrows by plot, making three replicates per each hybrid. the sampling was made taking three plants per treatment for each replicate, and in four phenological phases: v6; v10; r1; r5.5 and r6. dry matter, nitrogen content and foliar nitrogen were determined by the semi-microkjeldahl method (b). by using the nitrogen dilution curve it could be detected that the content of nitrogen in both hybrids was higher than the required quantity for the maximum growth rate till the flowering, and that the nitrogen values obtained in r1 and r6 were under the curve of dilution of equation (a), indicating a deficit of nitrogen. this methodology is not practical to judge the nitrogenous state of the crop in the stages after flowering, because the composition of the dry matter changes after this phase and the oil synthesis phase begins.
Determinación de la Curva de Dilución de Nitrógeno en Diferentes Fases Fenológicas del Girasol Determination of the Nitrogen Dilution Curve in Different Phenological Phases of Sunflower
Gladis A de Caram,Patricia Angeloni,Juan Prause
Agricultura Técnica , 2007,
Abstract: La concentración de nitrógeno que le permite al cultivo alcanzar la tasa de crecimiento máxima se denomina concentración crítica; estas concentraciones varían de acuerdo a la biomasa aérea considerada, ya que a medida que ésta aumenta se produce un efecto de dilución del nitrógeno en la planta. El objetivo del trabajo fue caracterizar el estado nutricional en nitrógeno foliar de dos híbridos de girasol (Helianthus annuus L.), en distintas fases fenológicas, empleando la curva de dilución del nitrógeno en la materia seca aérea total. Los tratamientos fueron dos híbridos, GUARANI DC y DKSOL 4040, que se sembraron a razón de cuatro surcos por parcela, realizándose tres repeticiones por híbrido. El muestreo se realizó tomando tres plantas por tratamiento para cada repetición, en cinco fases fenológicas: V6; V10; R1; R5.5 y R6. Se determinaron materia seca, contenido de nitrógeno y nitrógeno foliar por el método semi-microKjeldahl. Utilizando la curva de dilución del nitrógeno se detectó que el contenido de nitrógeno en ambos híbridos fue superior a la cantidad necesaria para el cultivo hasta la floración y que los valores de nitrógeno obtenidos en R1 y R6, estuvieron por debajo de la curva de dilución. Esta metodología no es utilizable para juzgar el estatus de N del cultivo en estadios posteriores a floración, ya que después de dicha fase, cambia la composición de la materia seca, dando comienzo a la etapa de la síntesis de aceite The concentration of nitrogen which allows a crop to reach its maximum growth rate is called critical concentration. This concentration varies according to the aerial biomass considered, as when this increases, there is a dilution effect of the nitrogen in the plant. The aim of this work was to characterize the nutritional state of foliar nitrogen in two sunflower hybrids (Helianthus annuus L.), at different phenological phases, using the nitrogen dilution curve in total aerial dry matter. The treatment was applied to two hybrids, GUARANI DC and DKSOL 4040, sown in four furrows by plot, making three replicates per each hybrid. The sampling was made taking three plants per treatment for each replicate, and in four phenological phases: V6; V10; R1; R5.5 and R6. Dry matter, nitrogen content and foliar nitrogen were determined by the semi-microKjeldahl method (B). By using the nitrogen dilution curve it could be detected that the content of nitrogen in both hybrids was higher than the required quantity for the maximum growth rate till the flowering, and that the nitrogen values obtained in R1 and R6 were under the curve of dilution o
CAMBIOS PRODUCIDOS EN UN SUELO BAJO LABRANZA CONSERVACIONISTA Y SIEMBRA DIRECTA DE ALGODóN EN EL CHACO, ARGENTINA
Prause,Juan; Soler,Jorge;
Agricultura Técnica , 2001, DOI: 10.4067/S0365-28072001000400016
Abstract: cotton (gossypium hirsutum l.) farming represents 49% of the surface of annual crops of chaco province, argentina. during the last 7 years, direct drilling has spread in some areas of the southwest of the province, in opposition to the traditional tillage systems. with the objective of evaluating the effects of the conservation tillage (lc) and the direct drilling (sd) on argiustol udico soil on cotton, the following were determined: soil water content, bulk density, ph, organic matter, assimilable phosphorus and exchangeable calcium, magnesium, sodium and potassium. the results indicate that sd caused an increase in bulk density and ph values at a depth of 0 - 15 cm. there were no differences between sd and lc for organic matter, p, ca, mg y na. a better response to conservation of soil moisture was found with lc during a long drought.
CAMBIOS PRODUCIDOS EN UN SUELO BAJO LABRANZA CONSERVACIONISTA Y SIEMBRA DIRECTA DE ALGODóN EN EL CHACO, ARGENTINA Changes produced in a soil under conservation tillage and direct drilling of cotton in Chaco, Argentina
Juan Prause,Jorge Soler
Agricultura Técnica , 2001,
Abstract: El cultivo del algodón (Gossypium hirsutum L.) representa el 49% de la superficie de cultivos anuales en la Provincia del Chaco, Argentina; en los últimos 7 a os, en algunas zonas del sudoeste chaque o se ha difundido el sistema de siembra directa en algodón, en oposición a los sistemas de labranzas tradicionales. Con el objeto de evaluar los efectos que sobre un suelo Argiustol údico tienen la labranza conservacionista (LC) y la siembra directa (SD) en algodón, se determinaron humedad presente, densidad aparente, pH, materia orgánica, fósforo asimilable, calcio, magnesio, sodio y potasio intercambiables. Los resultados obtenidos indican que SD provocó un incremento en la densidad aparente y en valores de pH en la profundidad de 0 - 15 cm. No se apreciaron diferencias entre la SD y LC para materia orgánica, P, Ca, Mg y Na. Durante una prolongada sequía se encontró mejor respuesta a la conservación de la humedad del suelo en LC que en SD. Cotton (Gossypium hirsutum L.) farming represents 49% of the surface of annual crops of Chaco Province, Argentina. During the last 7 years, direct drilling has spread in some areas of the southwest of the province, in opposition to the traditional tillage systems. With the objective of evaluating the effects of the conservation tillage (LC) and the direct drilling (SD) on Argiustol Udico soil on cotton, the following were determined: soil water content, bulk density, pH, organic matter, assimilable phosphorus and exchangeable calcium, magnesium, sodium and potassium. The results indicate that SD caused an increase in bulk density and pH values at a depth of 0 - 15 cm. There were no differences between SD and LC for organic matter, P, Ca, Mg y Na. A better response to conservation of soil moisture was found with LC during a long drought.
The precision of line position measurements of unresolved quasar absorption lines and its influence on the search for variations of fundamental constants
Nils Prause,Dieter Reimers
Physics , 2013, DOI: 10.1051/0004-6361/201118373
Abstract: Optical quasar spectra can be used to trace variations of the fine-structure constant alpha. Controversial results that have been published in last years suggest that in addition to to wavelength calibration problems systematic errors might arise because of insufficient spectral resolution. The aim of this work is to estimate the impact of incorrect line decompositions in fitting procedures due to asymmetric line profiles. Methods are developed to distinguish between different sources of line position shifts and thus to minimize error sources in future work. To simulate asymmetric line profiles, two different methods were used. At first the profile was created as an unresolved blend of narrow lines and then, the profile was created using a macroscopic velocity field of the absorbing medium. The simulated spectra were analysed with standard methods to search for apparent shifts of line positions that would mimic a variation of fundamental constants. Differences between position shifts due to an incorrect line decomposition and a real variation of constants were probed using methods that have been newly developed or adapted for this kind of analysis. The results were then applied to real data. Apparent relative velocity shifts of several hundred meters per second are found in the analysis of simulated spectra with asymmetric line profiles. It was found that each system has to be analysed in detail to distinguish between different sources of line position shifts. A set of 16 FeII systems in seven quasar spectra was analysed. With the methods developed, the mean alpha variation that appeared in these systems was reduced from the original Dalpha/alpha=(2.1+/-2.0)x10^-5 to Dalpha/alpha=(0.1+/-0.8)x10^-5. We thus conclude that incorrect line decompositions can be partly responsible for the conflicting results published so far.
On a H?lder constant in the theory of quasiconformal mappings
István Prause
Mathematics , 2013, DOI: 10.1007/s40315-014-0060-4
Abstract: A K-quasiconformal selfmap of the unit disk with identity boundary values satisfies the H\"older estimate $|f(z)-f(w)| \leq 4^{1-1/K} |z-w|^{1/K}$. The constant $4^{1-\frac{1}{K}}$ is sharp.
Quasisymmetric distortion spectrum
István Prause,Stanislav Smirnov
Mathematics , 2009, DOI: 10.1112/blms/bdq098
Abstract: We give improved bounds for the distortion of the Hausdorff dimension under quasisymmetric maps in terms of the dilatation of their quasiconformal extension. The sharpness of the estimates remains an open question and is shown to be closely related to the fine structure of harmonic measure.
EVALUACIóN DE LA ACTIVIDAD RADICAL EN Schinopsis balansae Engl. EMPLEANDO 32P
Prause,Juan; Marinich,María J.;
Agricultura Técnica , 2000, DOI: 10.4067/S0365-28072000000400011
Abstract: the study was conducted on a population of quebracho colorado chaque?o (schinopsis balansae engl.), the principal forest species of economic value in argentina?s chaque?o húmedo park. individuals of this species were selected according to their height and trunk diameter (dap). a solution of kh2 32po4 was applied at two different depths 0.10 m and 0.20 m. for 70 days, the concentration of radioactivity in whole mature leaves in the one year old branches was determined weekly. the presence of physiologically active roots was detected at both depths, but the highest root activity was registered at 0.10 m coinciding with the a soil horizon
Concentración estacional de micronutrientes en hojas de cuatro especies forestales del Parque Chaque o, Argentina Seasonal micronutrients concentration in leaves of four forest species from Parque Chaque o, Argentina
Juan Prause,Carolina Fernández López
Revista de Biología Tropical , 2012,
Abstract: El ciclo de nutrientes es uno de los componentes fundamentales en el funcionamiento de los ecosistemas forestales. Las hojas de diferentes especies forestales muestran distinta composición química y diferencias estacionales en la producción de biomasa atribuidas a las fluctuaciones climáticas y/o cambios en la fenología de las plantas y a la variación en el contenido de nutrientes. El objetivo del trabajo fue analizar la variación estacional de las concentraciones de Fe, Mn, Cu y Zn en hojas de: Gleditsia amorphoides (Ga), Patagonula americana (Pa), Maclura tinctoria (Mt) and Astronium balansae (Ab). El sitio de estudio fue localizado en la Reserva Natural Estricta de Colonia Benítez (Chaco, Argentina). Las hojas de cada especie forestal fueron recogidas mensualmente, secadas a 70oC, se determinó su peso seco y posteriormente se molió. El análisis foliar se realizó por oxidación húmeda empleando una mezcla ternaria HNO -H SO -HclO. Después de la digestión la concentración total de micronutrientes foliares fue determinada por espectrometría de absorción atómica. Las mayores concentraciones de Fe fueron para Mt (76.1mg/kg), Pa (75.2mg/kg), Ab (59.5mg/ kg) y Ga (45.3mg/kg). En Mn las más altas concentraciones se detectaron en Pa (54.0mg/kg), Ga (50.0mg/kg), Mt (48.0mg/kg), y la menor en Ab (39.7mg/kg). No se hallaron diferencias significativas entre las especies forestales para Cu foliar en Pa (11.3mg/kg), Ga y Mt (11.0mg/kg) y Ab (10.4mg/kg). Las mayores concentraciones foliares de Zn fueron en Mt (347.4mg/kg), Ga (319.9mg/kg), Pa (280.2mg/kg) y Ab (255.7mg/kg). En las especies forestales estudiadas, la concentración de los micronutrientes analizados mostraron una errática variación estacional, que puede ser atribuida a las relaciones establecidas entre las especies nativas bajo la fuerte influencia del ambiente, especialmente temperaturas y precipitaciones, durante un largo período de tiempo. Nutrients cycling is a fundamental component in the functioning of forest ecosystems. Leaves of different forest species observe specific chemical composition, and some seasonal differences in biomass production, may be related to climate fluctuations and/or changes in plant phenology and the variation on nutrient contents. The objective of this study was to analyze the seasonal variability of Fe, Mn, Cu and Zn concentrations in leaves of Gleditsia amorphoides (Ga); Patagonula americana (Pa); Maclura tinctoria (Mt) and Astronium balansae (Ab) from Colonia Benítez Strict Nature Reserve (Chaco, Argentina). The leaves of each forest species were collected monthly, dried
EVALUACIóN DE LA ACTIVIDAD RADICAL EN Schinopsis balansae Engl. EMPLEANDO 32P Evaluation of the radical activity in Schinopsis balansae Engl. using 32P
Juan Prause,María J. Marinich
Agricultura Técnica , 2000,
Abstract: Se realizó un estudio en una población de quebracho colorado chaque o (Schinopsis balansae Engl.), principal especie forestal de valor económico del Parque Chaque o Húmedo de Argentina, seleccionando ejemplares por su altura y diámetro altura de pecho (DAP). Se colocó una solución de KH2 32PO4 , a 0,10 m y 0,20 m de profundidad. Semanalmente durante 70 días, se determinó la concentración de radioactividad en hojas maduras y enteras de las ramas de un a o. En ambas profundidades se detectó la presencia de raíces fisiológicamente activas, siendo mayor en la profundidad de 0,10 m, coincidiendo con la profundidad del horizonte A The study was conducted on a population of quebracho colorado chaque o (Schinopsis balansae Engl.), the principal forest species of economic value in Argentina’s Chaque o Húmedo Park. Individuals of this species were selected according to their height and trunk diameter (DAP). A solution of KH2 32PO4 was applied at two different depths 0.10 m and 0.20 m. For 70 days, the concentration of radioactivity in whole mature leaves in the one year old branches was determined weekly. The presence of physiologically active roots was detected at both depths, but the highest root activity was registered at 0.10 m coinciding with the A soil horizon
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