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Search Results: 1 - 10 of 10267 matches for " Sandra Loera-Serna "
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Chemical Degradation of Indigo Potassium Tetrasulfonate Dye by Advanced Oxidation Processes  [PDF]
Veronica Camargo, Elba Ortiz, Hugo Solis, Carlos M. Cortes-Romero, Sandra Loera-Serna, Carlos J. Perez
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.513128
Abstract: The experimental degradation of a water soluble dye, potassium indigo tetrasulfonate salt, has been studied using stand-alone ozonation and photocatalytic oxidation process. Progress of the dye oxidation was followed by UV-VIS spectrophotometric measurements at controlled operating conditions. The organic content of reaction samples was measured to verify the process efficiency in dye mineralization. According to current results, almost complete color removal was obtained for ozonation within about 1 h reaction time. The reduction of the organic load was almost 80% from its original while initial sulphur content decreased to 32.5%. Dye conversion of 100% was obtained by means of a photocatalytic process using TiO2 as catalyst at 294 nm irradiated UV light. This complete color removal for the catalytic process was observed within 7 min of reaction time. The calculated initial rate of reaction of photocatalysis treatment was 8 times faster than that of ozonolysis. However, the remaining organic load of photocatalysis was almost 88% from its original while the final sulphur content was 27.3%. This contrasting behavior of the performance of the type of oxidation process stressed importance of physicochemical phenomena and intermediates molecules present during dye degradation. An insightful and mechanistic aspect of the dye oxidation was developed by performing quantumchemical calculations.
Degradation of Indigo Carmine Using Advanced Oxidation Processes: Synergy Effects and Toxicological Study  [PDF]
Elba Ortiz, Violeta Gómez-Chávez, Carlos M. Cortés-Romero, Hugo Solís, Rubén Ruiz-Ramos, Sandra Loera-Serna
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.712137
Abstract:
The physicochemical degradation of Indigo Carmine (IC) dye in aqueous solution was performed using single and combined Advanced Oxidation Processes (AOP’s). Photocatalysis (TiO2-UV), Ozonation (O3) and Sonolysis (SN) were tested either in a standalone methodology or by combination of two simultaneous AOP’s. The dye conversion was followed by both measurements: 1) color removal determined by UV-VIS spectrometry and 2) organic and inorganic load determined by the chemical oxygen demand (COD). A complete and quick color disappearance of model water waste has been obtained by using combination of non-irradiated AOP’s, namely, O3/SN, which contrasts to the combination of irradiated photocatalysis with O3 or sonolysis. Color removal with simultaneous TiO2-UV/SN reached 77% while TiO2-UV/O3 reached 96% at similar reaction time. On the other hand, the standalone O3 yielded the highest color removal (94.4%) in 32 minutes whereas SN reached only 39.2% in 4 hours. The standalone light irradiated TiO2-UV reached 93.3% color re-moval in one hour of reaction time. These results indicated that non-irradiated (SN and O3) enhance synergistic effects that provoke structural changes in dye molecule without reaching total degradation. This is evidenced from FTIR of residuals from reaction mixture in which it has been observed the presence of organic molecules such as aromatics, sulfonic and amines refractory compounds that are mechanisti-cally possible to be found during IC degradation. Also, toxicity tests (MicroTox
Producción y tecnología de la Okra (Abelmoschus esculentus) en el noreste de México
Díaz Franco, Arturo;Loera Gallardo, Jesús;Rosales Robles, Enrique;Alvarado Carrillo, Manuel;Ayvar Serna, Sergio;
Agricultura técnica en México , 2007,
Abstract: in mexico, the okra is a non-traditional vegetable cultivated in 4000 to 7000 ha annually with an average yield of 10 t ha-1; most of the production is exported to the united states of america. main okra producer states include: morelos, michoacan, guerrero and tamaulipas. in this last state okra is produced in up to 5 000 ha. okra is a rentable vegetable crop that also promotes hand labor. research on okra started in mexico twenty years ago. fruit quality is a key factor for okra marketing; soft texture fruits with intense green color and of regular shape are preferred. higher okra yield are obtained in clay loam soils. a problem for crop establishment are the low soil temperatures that causes low okra emergence in early plantings. foliar fertilization has not being effective to increase yields. pruning is a promising practice because its optimizes crop yields by extending the crop season. some okra hybrids tested in the region show productive advantages in relation to the traditional cultivar 'clemson spineless'. the most important disease is yellow mottled virus, transmitted by whiteflies (trialeurodes vaporariorum). this virus has caused the abandonment of the okra crop in the states of guerrero and morelos. ineffective weed control in okra has deleterious effects on yield, increases production cost and difficults harvest.
Colémbolos asociados con cultivos de pastos en tres zonas de vida
Ospina S. Claudia Marcela,Serna C. Francisco Javier,Pe?aranda P. Martha Rocío,Serna G. Sandra Luz
Agronomía Colombiana , 2003,
Abstract: Los colémbolos son artrópodos muy peque os, sin alas, similares a los insectos y extremadamente abundantes en gran cantidad de hábitat, siendo uno de los grupos de hexápodos mejor representados en el mundo. Son muy importantes por su influencia sobre la estructura de algunos suelos, no pocos viven en el dosel de las selvas tropicales y algunos actúan como dispersores de esporas dentro de los troncos en descomposición. En Colombia existen muy pocos estudios de reconocimiento de colémbolos. En la literatura se registran 12 especies en dos localidades cerca de Buenaventura, agrupadas en 5 familias; así mismo, han sido reconocidas en diferentes estudios otras 7 especies que actúan como plagas en Musáceas y en flores cultivadas. Con el fin de contribuir al conocimiento de las familias de Collembola asociadas con suelos de pastos cultivados en el departamento de Antioquia se hicieron muestreos en tres zonas de vida de Holdridge (bh-P, bh-MB y bs-T) en pastos Guinea ( Panicum maximum), ángleton ( Dichanthium aristatum), Estrella (Cynodon nlemfluensis), Braquiaria ( Brachiaria decumbens), kikuyo (
USE OF SOIL MICROORGANISMS AS A BIOTECHNOLOGICAL STRATEGY TO ENHANCE AVOCADO (Persea americana)-PLANT PHOSPHATE UPTAKE AND GROWTH USO DE MICROORGANISMOS DEL SUELO COMO ESTRATEGIA BIOTECNOLóGICA PARA MEJORAR LA ABSORCIóN DE FóSFORO Y EL CRECIMIENTO DE PLANTAS DE AGUACATE (Persea americana)
Nelson Walter Osorio Vega,Sandra Luz Serna Gómez,Beatriz Elena Montoya Restrepo
Revista Facultad Nacional de Agronomía, Medellín , 2012,
Abstract: . In recent years the area cultivated with avocado has increased significantly in Colombia and this trend is expected to continue in the coming years. However, most of the soils in the highlands of the Colombian Andean, that have been used to grow avocado, are strongly acidic and nutrient deficient, particularly phosphorus (P). To alleviate these problems, high rates of lime and P fertilizers are frequently applied, in many cases the applied dose are excessive. This increases production costs, produces plant nutrient imbalance in the plant, and increases the risk of polluting surface waters. A biotechnological alternative is the combined use of phosphate solubilizing microorganisms (PSM) and arbuscular mycorhizal fungi (AMF). This work describes a series of experiments carried out to isolate, characterize, and evaluate the effectiveness of AMF and PSM in increasing plant growth and P uptake of avocado plants. The results indicate that the mycorrhizal association is an effective alternative that can easily be established in the crops; however, the excessive use of P fertilizer in these soils may limit the benefits of these fungi on avocado plants. Currently, effective PSM of avocado rhizosphere have not been detected. In some cases, these microorganisms are absent in the avocado rhizosphere and in other cases their low capacity to solubilize P discourage their use in the crop. Resumen. En los últimos a os el área cultivada con aguacate en Colombia ha crecido notoriamente y se espera que esta tendencia continúe en los próximos a os. Sin embargo, muchos de los suelos de la zona andina utilizados para su siembra exhiben fuerte acidez y niveles deficientes de varios nutrientes, particularmente fósforo (P). Para corregir este problema se hacen aplicaciones de cales y fertilizantes fosfóricos solubles, en mucho casos las dosis aplicadas son altas. Esto eleva innecesariamente los costos de producción, crea desbalance nutricional en la planta y genera riesgos de contaminación ambiental. Una alternativa biotecnológica es el uso de microorganismos solubilizadores de fosfato (PSM) y hongos formadores de micorriza-arbuscular (AMF). En este trabajo se describe el aislamiento, caracterización y evaluación de la efectividad de AMF y PSM para mejorar la absorción de P por las plantas de aguacate. La asociación micorrizal ha probado ser una alternativa factible de implementar; sin embargo, el excesivo uso de fertilizantes fosfóricos puede limitar los beneficios de estos hongos en las plantas de aguacate. Hasta ahora no se han detectado PSM efectivos en la rizosfe
EXPERTCHOICE DECISION SUPPORT SYSTEM IMPLEMENTATION FOR VEHICLE SELECTION IN A COLOMBIAN SHIPYARD
JULIAN ANDRES ZAPATA CORTES,MARTIN DARíO ARANGO SERNA,SANDRA PATRICIA MORENO MARTíNEZ
DYNA , 2012,
Abstract: El presente artículo muestra la aplicación del sistema de soporte de decisiones DSS (Decision support systems) para la selección de automóviles tipo camionetas en un astillero colombiano. El artículo comienza con una descripción acerca de estos sistemas de soporte de decisión, se analiza la disponibilidad de los mismos en el mercado y finaliza con la aplicación del sistema DSS Expertchoice para la selección de las camionetas en la empresa de estudio.
A máquina dos Sem-Terra
Nashieli Cecilia Rangel Loera
Revista Theomai , 2004,
Abstract: The landless workers movement (MST) of Brazil is one of the largest peasant organization of Latin America. This social movement shows us innovative strategies in the struggle for land. The massive occupation of land is one of them. The social network (kinship, neighborhood, friendship, affinity and mobilization) go beyond the frontiers of the camps and the settlements organized by the MST and it allows the continuity and the survival of this organization but became a central element on land occupation and sets the engine of the landless workers in motion
“Tourism Potentiality” as an Additional Activity for Socio-Economic Development of the Fishing Field in Las Aguamitas, Sinaloa, Mexico  [PDF]
Marcela Rebeca Contreras-Loera, Elizabeth Olmos-Martinez
Modern Economy (ME) , 2014, DOI: 10.4236/me.2014.56063
Abstract:

Riparian rural communities are characterized as spaces whose main activity is the exploitation of natural resources of the sea, but the diversification of economic activities is an option to change their current situation. The fishing cooperative plays a critical role in addressing the challenges imposed by the demands of today’s world. It is necessary to implement practices that contribute to economic, social and ecological development of the locality. This paper presents results of research whose objective was to identify the tourism potentiality as a complementary activity to economic and social development of the rural community in Las Aguamitas and the role of the fishing cooperative Barra de La Tonina, in local community development. Data collection was conducted through semi-structured interviews and observation. In addition, a survey to characterize socioe-conomically cooperative members was applied. The findings indicate that Las Aguamitas is a rural community with a wide range of natural and human resources to promote and encourage tourism. Even though the members of the cooperative and the community residents offer travel services, these are informal and without professionalization of the activity. From the above, it is concluded that the rural community has potential for tourism as a complementary activity for socioeconomic development, however it needs to train and professionalize the activity.

Reconversión y conservadurismo político en Brasil: los límites del cambio
Serna, Miguel;
Sociedade e Estado , 2006, DOI: 10.1590/S0102-69922006000200006
Abstract: drawing on comparative historical perspective, the article examines the recent political changes in the party system and brazilian democracy. on the one hand, the paper explains historical restrictions on the democratization processes. on the other hand, it highlights the inheritance of conservative sociopolitics matrix on the dynamics of electoral changes. the first section analyzes the conservative sociopolitics matrix?s development and identifies democratization processes? weaknesses between 1945 and 1964. the second section focuses on political parties and democracy development during the last decades to identify the limits of the recent political changes.
Vivir de los Imaginarios del Mar: Restaurantes y Estereotipos Sobre el Pacífico en Bogotá
Serna,Sonia;
Tabula Rasa , 2011,
Abstract: restaurants serving food from the pacific region in the capital city of bogotá have become an inescapable reference when it comes to reflect on black people4 dynamics in this city. however, they have often been minimized and seen under the light of a few spots located in specific sites, and holding akin trajectories, which has resulted in generalizing the phenomenon of their recent thriving, and concealing the complexity of histories behind each of them. face to the wide and growing emergence of these spots throughout the city, and based on fieldwork experiences, i aim to challenge some representations pervading both in scholar imaginaries and people who play the part of their clientele. my central argument is that these restaurants are not a result of an attained/gained social order, as it has been often stated, but they are rather reproducing a stereotyped social order that fixes difference while shaping and visibilizing a particular view of the pacific region.
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