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Search Results: 1 - 10 of 592861 matches for " L. García-Ravidá "
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J. Reinaldo Martínez-Fernández,L. García-Ravidá
Abstract: En este trabajo analizamos los patrones de aprendizaje (Vermunt, 1998; 2005) en una muestrade estudiantes universitarios del Máster en Formación del Profesorado de Educación Secundaria, y la relación que tienen con ciertas variables personales, contextuales y el rendimiento académico. Participan 101 estudiantes de Formación del Profesorado de una universidad espa ola con una edad media de 27.57, de los cuales 71.30% son mujeres. Los resultados indican que no se reproducen, fielmente, los patrones propuestos por Vermunt, aunque si se aprecia una mayor semejanza conlos resultados que otros trabajos han hallado empleando el ILS con muestras de estudiantes de Educación Secundaria. Igualmente, hallamos relaciones significativas entre el género femenino y mayorespuntuaciones en creencias y orientaciones de aprendizaje y entre la edad con mayores puntuacionesen los indicadores del patrón reproductivo y la orientación a calificaciones y certificados. Además, hallamos que los estudiantes de orientación educativa tienen menor puntuación en elpatrónreproductivo que los estudiantes de ciencias naturales. Estos resultados se discuten en el marco de la formación universitaria del profesorado de Educación Secundaria en una universidad espa ola.
Building a Methodology for the Design of an Environmental Services Payment Programme for the Mangroves of Mexico  [PDF]
Tania García López
Open Journal of Ecology (OJE) , 2018, DOI: 10.4236/oje.2018.83010
Abstract: Environmental Services Payment Programmes are not entirely new and they are more flexible than the usual command-and-control type of regulation. In the 1990s for example, an Environmental Services Payment programme was introduced to cope with the forestry system and pay benefits to farmers for the good that their forests would produce. This review examines the possibility of using Environmental Services Payment programmes for Mexican mangroves as they are an important resource against natural disasters, and reducing greenhouse gases in the Earth’s atmosphere, for example, and they are constantly invaded by the human race which impacts on their destruction. The review aims at constructing a methodology that can be applied to the implementation of Environmental Services Payment programmes. The value of this study is in aiming a straight arrow at the environmental problems outlined in this paper, problems that have not been fully resolved to date, especially in Mexico where it is not officially recognised that mangroves play an important role in the mitigation of greenhouse gases. Furthermore, Environmental Services Payment Programmes in Mexico have not pinpointed specific types of area. We conclude this paper with elaborating on our ten-point strategy for implementing Environmental Services Payment programmes which includes, in brief: 1) Fully accepting the importance of the mitigation of greenhouse gases via mangroves; 2) designing a Environmental/Ecosystem Services Payment Programme with particular emphasis on Mexican mangroves; 3) identifying specific environmental services and their level from local to international; 4) formation and implementation of a system of “whoever benefits must pay”; 5) building of a knowledge base of owners and others who benefit from environmental services; 6) hypothetical models of particular Environmental Services Payment programmes must be constructed; 7) clarifying who must pay; 8) grouping all sectors that must pay; 9) inspiring all actors to cooperate via 10) the impact of a Citizens’ Council, for example.
Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC): Occlusive Effect and Penetration Enhancement Ability  [PDF]
R. López-García, A. Ganem-Rondero
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2015, DOI: 10.4236/jcdsa.2015.52008
Abstract: Objective: This work compares the occlusive effect and the penetration enhancement ability of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), through in vitro skin. Methods: SLN and NLC were prepared by high shear homogenization and characterized by size, polydispersity index, zeta potential, morphology and physical stability. Occlusive effect was assessed by an in vitro test and by measuring TEWL using pig skin. Skin treated with the lipid carriers was visualized by SEM. A penetration test through skin, followed by tape stripping, was carried out using Nile red as a marker. Results: SLN (200 ± 6 nm) and NLC (192 ± 11 nm) were obtained. An occlusion factor of 36% - 39% was observed for both systems, while a reduction in TEWL of 34.3% ± 14.8% and 26.2% ± 6.5% was seen after treatment with SLN and NLC, respectively. SEM images showed a film formed by the lipid carriers, responsible for the occlusion observed. No differences were found between the occlusive effect produced by SLN and NLC in both tests. NLC allowed the penetration of a greater amount of Nile red than SLN: 4.7 ± 1.3 μg and 1.7 ± 0.4 μg, respectively. Conclusion: Both carriers form a film on the skin, providing an occlusive effect with no differences between these two systems. The penetration of a marker (Nile red) into the stratum corneum was quite higher for NLC than for SLN, suggesting an influence of the composition of these particles on their penetration enhancing ability.
Adhesión a dentina afectada por caries y dentina esclerótica
Ceballos García,L.;
Avances en Odontoestomatología , 2004, DOI: 10.4321/S0213-12852004000200002
Abstract: these are two kinds of dentin which are less receptive to adhesion and clinically more important than sound dentino their histopathological and physiological characteristics were described and a literature review was performed evaluating adhesion to these two kinds of altered dentin.
García L.,Carolina;
Boletín de Ciencias de la Tierra , 2006,
Abstract: surface formations of the aburra valley include several successive genetically similar series of extensive fluvial and slope deposits, possibly generated by events of intense tectonic activity. these deposits display a typical stepped structure, in which older deposits are located in the upper part of slopes and the recent ones, sometimes derivated form the older, are located in the lower part of the slope. although in the last two decades several works emphasize the importance of these deposits in the evolution of the aburra valley, few are those with chronological relations sustained in ages obtained by absolute dating which would allow to confirm the relations of the deposits with important orogenic events. the absolut ages until the moment are 3,12 ma (rendón et al., in press) for the older deposits and 0,19 ma (aristizabal, 2004) to 0,62 (ortiz, 2002) for the recent deposits of the serie.
Suelos de las Islas Chafarinas y sus relaciones ecológicas
L. V. García
Ecosistemas , 2005,
Adhesión a dentina afectada por caries y dentina esclerótica Adhesion to caries affected and sclerotic dentin
L. Ceballos García
Avances en Odontoestomatología , 2004,
Abstract: Se trata de formas de dentina alterada que son los substratos adhesivos más importantes clínicamente y menos receptivos a los tratamientos adhesivos que la dentina normal. Se describen la características histopatológicas y fisiológicas de: (1) dentina afectada por caries (ya sea en su capa superficial o en su capa profunda) y (2) dentina esclerótica. Se realiza una revisión de la literatura estudiando la adhesión a estos tipos de dentina. These are two kinds of dentin which are less receptive to adhesion and clinically more important than sound dentino Their histopathological and physiological characteristics were described and a literature review was performed evaluating adhesion to these two kinds of altered dentin.
Determination of Young Olive-Tree Water Consumption with Drainage Lysimeters  [PDF]
L. Puppo, C. García, J. Girona, M. García-Petillo
Journal of Water Resource and Protection (JWARP) , 2014, DOI: 10.4236/jwarp.2014.69079

Information about olive-tree irrigation in sub-humid climates, as in Uruguay, is scarce. Water consumption of young olive trees, Arbequina variety, was measured for two years with six drainage lysimeters, protected from rain by an automatic rain-out shelter. Irrigation water volume and drainage of each lysimeter were measured daily and soil moisture was registered twice a week with neutron probe at four depths. Evapotranspiration (ETc) was calculated by volume balance. Data periods when available water descended below 50% or increased over 100% were eliminated, as those in which the stem water potential was below -1.5 MPa. Water consumption values were averaged within 7- to 14-day periods, expressed in mm·d-1, and referred to a 2.5 × 5.5 m plantation framework without vegetation cover. There was a positive linear relation of the summer crop coefficient (Kc mid) with age, canopy cover percentage and canopy volume. Canopy cover percentage was the parameter which explained most of the variation of Kc mid, which ranged between 0.13 and 0.24, with 5% and 46% canopy cover, respectively. Full irrigation, associated to a good drainage resulted in a rapid growth of the young plants, bringing forward the start of full production period. This represents useful information for the adjustment of irrigation in olive-tree orchards, to accelerate growth with a rational and sustainable use of both water and energy in Uruguay.

Economic Assessment and Socio-Economic Evaluation of Water Use Efficiency in Artichoke Cultivation  [PDF]
José García García, Fulgencio Contreras López, Domenico Usai, Caterina Visani
Open Journal of Accounting (OJAcct) , 2013, DOI: 10.4236/ojacct.2013.22008
Abstract: The aim of this work is to provide a methodology for analysing socioeconomic aspects of water resource management that will provide with an objective decision making tool. To validate the proposed analysis method here, we refer to three artichoke production options. The economic evaluations indicate that the drip irrigation systems are viable and profitable. The traditional method of flooding is not a viable option despite needing the lowest investment, but is close to the viability threshold. In reference to water use efficiency, option 1 is by far the most effective (3.60 kg·m-3 compared with 2.25 and 2.18 kg·m-3, respectively). In our analysis we find that the most productive systems generate the most employment per unit of surface area. Option 1 is the most competitive in relation with the water factor, since it could support prices up to 0.53 €·m-3 and still be economically viable. System 2 will not be viable if the price exceeds 0.22 €·m-3. Option 3 is viable up to 0.17 €·m-3, which is more than is paid at the present time in Sardinia, although such an option would not be viable in south-eastern Spain.
Photoluminescence and Structural Properties of ZnO Nanorods Growth by Assisted-Hydrothermal Method  [PDF]
S. López-Romero, M. García-H
World Journal of Condensed Matter Physics (WJCMP) , 2013, DOI: 10.4236/wjcmp.2013.33024

Semiconducting zinc oxide (ZnO) nanorods were obtained in bulk quantity by an hexamethylenetetramine (HMTA)-assisted hydrothermal method at low temperature (90°C) with methenamine ((CH3)6N4 as surfactant and catalyst and zinc nitrate Zn(NO3)2·6H2O as Zn source. The structure and phase of ZnO nanorods were studied using x-ray diffraction (XRD) and high resolution transmission electron microscopy techniques (HRTEM). The morphology of the nanostructures was studied by scanning electron microscope (SEM) method. The photoluminescence (PL) properties were investigated founding two emission bands under UV excitation.

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