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Search Results: 1 - 10 of 1752 matches for " Hamil Uribe "
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EFECTO DE TRES SISTEMAS DE LABRANZA SOBRE EL NIVEL DE HUMEDAD EN EL PERFIL DEL SUELO
Uribe C.,Hamil; Rouanet M.,Juan L.;
Agricultura Técnica , 2002, DOI: 10.4067/S0365-28072002000400007
Abstract: conservationist tillage systems have advantages over conventional systems because they allow the protection of natural resources. however, it is important to validate these advantages to encourage the adoption of this type of technology by farmers. the objective of this study was to determine if the type of tillage affects moisture content in the soil profile. to this end, the effect of three tillage systems on water availability in an ultisol soil was compared. the treatments were: no tillage and burning residues (cl+q); no tillage without burning residues (cl-q); and traditional tillage (trad). the results showed that between end of tilling - beginning of internode elongation and heading, the mean value of the moisture index for cl-q was 1.023, significantly higher than 1.001 and 0.998 corresponding to cl+q and trad, while between heading and harvest the index for cl-q was 0.963, statistically higher than 0.941 and 0.938 corresponding to cl+q and trad. this effect was due to water content differences in the soil profile above 40 cm. considering the three periods of plant development together, the mean value of the moisture index for cl-q was 1.015, statistically higher than 0.996 and 0.990 from cl+q and trad. this study confirmed that in terms of soil moisture retention in the profile of an ultisol soil, it is recommendable to use zero tillage without burning the residues
EFECTO DE TRES SISTEMAS DE LABRANZA SOBRE EL NIVEL DE HUMEDAD EN EL PERFIL DEL SUELO Effect of three tillage systems on moisture content in the soil profile
Hamil Uribe C.,Juan L. Rouanet M.
Agricultura Técnica , 2002,
Abstract: Los sistemas de labranza conservacionista tienen ventajas sobre los convencionales, puesto que permiten proteger los recursos naturales. Sin embargo, es importante demostrar estas ventajas para fomentar la adopción de este tipo de tecnologías por los agricultores. El objetivo de este estudio fue determinar si el tipo de labranza afecta el contenido de humedad en el perfil del suelo. Para ello se comparó el efecto de tres sistemas de labranza sobre la disponibilidad de agua en un suelo Ultisol. Los tratamientos fueron: cero labranza con quema (CL+Q); cero labranza sin quema (CL-Q); y labranza tradicional (TRAD). Los resultados mostraron que entre término de macolla-inicio de enca ado y espigadura se obtuvo un índice de humedad promedio de 1,023 en CL-Q, que fue significativamente mayor a 1,001 y 0,998 correspondientes a CL+Q y TRAD, mientras que entre espigadura y cosecha el índice para CL-Q fue de 0,963, significativamente mayor a 0,941 y 0,938 correspondientes a CL+Q y TRAD, respectivamente. Este efecto se produjo gracias a las diferencias en los contenidos de humedad del perfil del suelo hasta los 40 cm. Al considerar los tres períodos fenológicos en conjunto el índice de humedad promedio obtenido en CL-Q fue 1,015, significativamente mayor que 0,996 y 0,990 de CL+Q y TRAD. Este trabajo permitió comprobar que desde el punto de vista de la retención de humedad en el perfil de un suelo Ultisol, es recomendable utilizar cero labranza sin quema de residuos Conservationist tillage systems have advantages over conventional systems because they allow the protection of natural resources. However, it is important to validate these advantages to encourage the adoption of this type of technology by farmers. The objective of this study was to determine if the type of tillage affects moisture content in the soil profile. To this end, the effect of three tillage systems on water availability in an Ultisol soil was compared. The treatments were: no tillage and burning residues (CL+Q); no tillage without burning residues (CL-Q); and traditional tillage (TRAD). The results showed that between end of tilling - beginning of internode elongation and heading, the mean value of the moisture index for CL-Q was 1.023, significantly higher than 1.001 and 0.998 corresponding to CL+Q and TRAD, while between heading and harvest the index for CL-Q was 0.963, statistically higher than 0.941 and 0.938 corresponding to CL+Q and TRAD. This effect was due to water content differences in the soil profile above 40 cm. Considering the three periods of plant development together, the mean
Unconfined Aquifer Permeability near hand-dug Wells in the Coastal and Interior dryland of the Libertador General Bernardo O'Higgins Region, Chile Permeabilidad de Acuíferos No-Confinados cerca de Pozos Norias en el Secano Costero e Interior, Región del Libertador General Bernardo O'Higgins, Chile
David E Rupp,Oscar Reckmann,Jorge Vergara,Hamil Uribe
Chilean Journal of Agricultural Research , 2011,
Abstract: In the dryland of the Libertador General Bernardo O'Higgins Region in Chile, most farmers rely on wide and shallow hand-dug wells as their primary source of water during the dry summer. Few of these wells have sufficient yield for more than domestic use (human consumption, livestock, and irrigation of a subsistence garden). To more accurately assess available groundwater resources, saturated hydraulic conductivity (K) of aquifers in the eight counties that comprise this region’s dryland was estimated using evacuation and recovery tests in 353 hand-dug wells. K followed a log-normal distribution and ranged over nearly five orders of magnitude. County median K varied by a factor of 5 and a slight increasing K trend in the southward direction. In one northern county, less than 4% of the sites had K > 4 m d-1. In the t two southernmost counties, approximately one-quarter of the K values exceeded 4 m d-1. This is approximately the minimum K required for a typical well (1 m diameter and 3 m depth below the water table) to yield 1 L s-1 of water, which is roughly the yield required to irrigate 1 ha. Aquifers located where parent material was predominantly intrusive granite had slightly higher and statistically significant K than those formed predominantly of metamorphic and sedimentary rock. A semi-variogram of K provided weak evidence of a characteristic length scale of approximately 4 km. La mayoría de los agricultores del secano de la Región del Libertador General Bernardo O'Higgins depende de pozos noria, constituyendo su principal fuente de agua durante el verano. Pocos pozos tienen rendimiento suficiente para un uso mayor que el doméstico (consumo humano, ganadería y riego). A fin de evaluar con mayor precisión los recursos hídricos subterráneos disponibles, mediante pruebas de bombeo-recuperación se estimó la conductividad hidráulica saturada (K) de los acuíferos en 353 pozos distribuidos en ocho comunas del área. K siguió una distribución log-normal, con una K máxima casi cinco órdenes de magnitud mayor que la mínima. La mediana de K varió en un factor de 5 por comuna y tuvo una ligera tendencia creciente en dirección Sur. En una comuna del Norte, se estimó que menos del 4% de los sitios presentaron K > 4 m d-1. En dos comunas del Sur, alrededor del 25% de los valores de K superaron los 4 m d-1, valor mínimo requerido para que un pozo de dimensiones típicas (1 m de diámetro y 3 m de profundidad bajo el nivel de agua) produzca 1 L s-1 de agua, suficiente para regar 1 ha. Los acuíferos localizados en áreas con material predominantemente granítico, tuvier
Influence of Conservation Tillage and Soil Water Content on Crop Yield in Dryland Compacted Alfisol of Central Chile Influencia de la Labranza de Conservación y el Contenido de Agua sobre el Rendimiento del Cultivo en un Alfisol compactado del Secano Central de Chile
Ingrid Martinez G,Carlos Ovalle,Alejandro Del Pozo,Hamil Uribe
Chilean Journal of Agricultural Research , 2011,
Abstract: Chilean dryland areas of the Mediterranean climate region are characterized by highly degraded and compacted soils, which require the use of conservation tillage systems to mitigate water erosion as well as to improve soil water storage. An oat (Avena sativa L. cv. Supernova-INIA) - wheat (Triticum aestivum L. cv. Pandora-INIA) crop rotation was established under the following conservation systems: no tillage (Nt), Nt + contour plowing (Nt+Cp), Nt + barrier hedge (Nt+Bh), and Nt + subsoiling (Nt+Sb), compared to conventional tillage (Ct) to evaluate their influence on soil water content (SWC) in the profile (10 to 110 cm depth), the soil compaction and their interaction with the crop yield. Experimental plots were established in 2007 and lasted 3 yr till 2009 in a compacted Alfisol. At the end of the growing seasons, SWC was reduced by 44 to 51% in conservation tillage systems and 60% in Ct. Soil water content had a significant (p < 0.05) interaction with tillage system and depth; Nt+Sb showed lower SWC between 10 to 30 cm, but higher and similar to the rest between 50 to 110 cm except for Ct. Although, SWC was higher in conservation tillage systems, the high values on soil compaction affected yield. No tillage + subsoiling reduced soil compaction and had a significant increment of grain yield (similar to Ct in seasons 2008 and 2009). These findings show us that the choice of conservation tillage in compacted soils of the Mediterranean region needs to improve soil structure to obtain higher yields and increment SWC. En Chile, las zonas de clima mediterráneo se caracterizan por suelos altamente degradados y compactados por erosión, lo que requiere el uso de sistemas de labranza conservacionista para mitigar la erosión hídrica, así como incrementar el contenido de agua en el suelo. Se evaluó una rotación avena (Avena sativa L. cv. Supernova-INIA) - trigo (Triticum aestivum L. cv. Pandora-INIA) establecida bajo los siguientes sistemas conservacionistas: cero labranza (Nt), Nt + curvas de nivel (Nt+Cp), Nt + franjas vivas (Nt+Bh) y Nt + subsolado (Nt+Sb), las que fueron comparadas al sistema de labranza convencional (Ct), para evaluar su influencia en el contenido de agua en el suelo (SWC) en el perfil (10 a 110 cm profundidad), la compactación del suelo y su interacción con el rendimiento del cultivo. Las parcelas experimentales fueron establecidas 3 a os seguidos (2007 al 2009) en un Alfisol compactado. Al final de la temporada, el SWC disminuyó 44 a 51% en los sistemas conservacionistas y 60% en el sistema convencional. El sistema de labranza y la profun
Unconfined Aquifer Permeability near hand-dug Wells in the Coastal and Interior dryland of the Libertador General Bernardo O'Higgins Region, Chile
Rupp,David E; Reckmann,Oscar; Vergara,Jorge; Uribe,Hamil; Selker,John S.;
Chilean journal of agricultural research , 2011, DOI: 10.4067/S0718-58392011000200012
Abstract: in the dryland of the libertador general bernardo o'higgins region in chile, most farmers rely on wide and shallow hand-dug wells as their primary source of water during the dry summer. few of these wells have sufficient yield for more than domestic use (human consumption, livestock, and irrigation of a subsistence garden). to more accurately assess available groundwater resources, saturated hydraulic conductivity (k) of aquifers in the eight counties that comprise this region?s dryland was estimated using evacuation and recovery tests in 353 hand-dug wells. k followed a log-normal distribution and ranged over nearly five orders of magnitude. county median k varied by a factor of 5 and a slight increasing k trend in the southward direction. in one northern county, less than 4% of the sites had k > 4 m d-1. in the t two southernmost counties, approximately one-quarter of the k values exceeded 4 m d-1. this is approximately the minimum k required for a typical well (1 m diameter and 3 m depth below the water table) to yield 1 l s-1 of water, which is roughly the yield required to irrigate 1 ha. aquifers located where parent material was predominantly intrusive granite had slightly higher and statistically significant k than those formed predominantly of metamorphic and sedimentary rock. a semi-variogram of k provided weak evidence of a characteristic length scale of approximately 4 km.
Braking index of isolated pulsars: open questions and ways forward
Oliver Hamil
Physics , 2015,
Abstract: Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\Omega$, and their time derivatives which show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of debate, the commonly accepted view is that it arises either through emission of magnetic dipole radiation (MDR) from a rotating magnetized body, through emission of a relativistic particle wind, or via higher order magnetic multipole or gravitational quadrupole radiation. The calculated energy loss by a rotating pulsar is model dependent and leads to the power law $\dot{\Omega}$ = -K $\Omega^{\rm n}$ where $n$ is called the braking index. The theoretical value for braking index is $n = 1, 3, 5$ for wind, MDR, quadrupole radiation respectively. The accepted view is that pulsar braking is strongly dominated by MDR. Highly precise observations of isolated pulsars yield braking index values in the range $1 < n < 2.8$ which are consistently less than the value predicted from the MDR model. We discuss possible ways to bring theory closer to observation for the MDR, and also consider how the other mechanisms may play a role in future study of the braking index problem.
Influence of Conservation Tillage and Soil Water Content on Crop Yield in Dryland Compacted Alfisol of Central Chile
Martinez G,Ingrid; Ovalle,Carlos; Del Pozo,Alejandro; Uribe,Hamil; Valderrama V,Natalia; Prat,Christian; Sandoval,Marco; Fernández,Fernando; Zagal,Erick;
Chilean journal of agricultural research , 2011, DOI: 10.4067/S0718-58392011000400018
Abstract: chilean dryland areas of the mediterranean climate region are characterized by highly degraded and compacted soils, which require the use of conservation tillage systems to mitigate water erosion as well as to improve soil water storage. an oat (avena sativa l. cv. supernova-inia) - wheat (triticum aestivum l. cv. pandora-inia) crop rotation was established under the following conservation systems: no tillage (nt), nt + contour plowing (nt+cp), nt + barrier hedge (nt+bh), and nt + subsoiling (nt+sb), compared to conventional tillage (ct) to evaluate their influence on soil water content (swc) in the profile (10 to 110 cm depth), the soil compaction and their interaction with the crop yield. experimental plots were established in 2007 and lasted 3 yr till 2009 in a compacted alfisol. at the end of the growing seasons, swc was reduced by 44 to 51% in conservation tillage systems and 60% in ct. soil water content had a significant (p < 0.05) interaction with tillage system and depth; nt+sb showed lower swc between 10 to 30 cm, but higher and similar to the rest between 50 to 110 cm except for ct. although, swc was higher in conservation tillage systems, the high values on soil compaction affected yield. no tillage + subsoiling reduced soil compaction and had a significant increment of grain yield (similar to ct in seasons 2008 and 2009). these findings show us that the choice of conservation tillage in compacted soils of the mediterranean region needs to improve soil structure to obtain higher yields and increment swc.
ERGENLERDE TüKET C L K B L N DüZEY üZER NE B R NCELEME
Seher ERSOY,M. Hamil NAZ?K
Selcuk Universitesi Sosyal Bilimler Enstitusu Dergisi , 2006,
Abstract: This study has been planned and applied to 316 students at the ages 12-14 educating in the6th, 7th and 8th classes of primary education in different socio-economical regions of Ankara, inorder to measure their knowledge and attitudes towards consumer education. For this purpose,“Consumer Education Knowledge Test” and “Consumer Education Attitude Scale” have beendeveloped by the researchers. According to the points of knowledge and attitude, the students’consumer education consciousness levels have been measured and discussed in connection withthe independent variables of family income, sex, class and parent’s education.By the study done, the requirement to give consumer education to adolescents who areregarded an important consumer group has been revealed.
Synthesis and Characterization of Some Ni(II) and Cu(II) Complexes with 2-[(4-Aminophenyl)imino]-1, 2-diphenyl-1-ethanone
K. M. Khalifa,A. M. Hamil,A. Gasem,A. Abdulsalam
Journal of Chemistry , 2010, DOI: 10.1155/2010/293904
Abstract:
Braking index of isolated uniformly rotating magnetized pulsars
Oliver Hamil,Jirina Stone,Martin Urbanec,Gabriela Urbancova
Physics , 2015,
Abstract: Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\Omega$, and their time derivatives which show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of debate in detail, the commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. Other processes, including the emission of gravitational radiation, and of relativistic particles (pulsar wind), are also being considered. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of $\Omega$. This relation leads to the power law $\dot{\Omega}$ = -K $\Omega^{\rm n}$ where $n$ is called the braking index. The MDR model predicts $n$ exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of $n$, individually accurate to a few percent or better, in the range 1$ <$ n $ < $ 2.8, which is consistently less than the predictions of the MDR model. In spite of an extensive investigation of various modifications of the MDR model, no satisfactory explanation of observation has been found as yet. We employ four physically realistic equations of state, and two computational codes, to model the dynamical effects of rotation on the braking index in the MDR model. In addition to this we simulate an effect on moment of inertia where we assume a certain amount of superfluid matter has manifest between the crust and core region of the star thus essentially eliminating momentum transfer between the two regions. We find that the effects of rotation on braking index are significant at high frequencies, but have little effect at frequencies consistent with the most accurately measured pulsars to-date.
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