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Search Results: 1 - 10 of 562316 matches for " Laverde Pe?a Héctor "
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Efecto de tres coberturas plásticas y dos sistemas de siembra en la fenología de la cebolla de bulbo Effect of three polyethylene mulchs and two plant systems on the phenology of the common onion (Allium cepa L.) at the Sabana de Bogota
Rondón Sandra Yaneth,Torres Becerra Nancy,Laverde Pea Héctor,Pinzón Hernán
Agronomía Colombiana , 1996,
Abstract: En el Centro de Investigaciones Agropecuarias Tibaitatá CORPOICA, se cultivo cebolla de bulbo (Allium cepa L.) híbrido Yellow Granex PRR, en siembra directa y trasplante, sobre tres coberturas plásticas (negra, gris y blanca), un testigo en suelo desnudo y un testigo absoluto, durante el segundo semestre de 1995 y los meses de Enero y Febrero de 1996. Para ambos sistemas de siembra, con las coberturas y sin elias, las plantas de cebolla presentaron las mismas fenofases, las cuales fueron: Emergencia, primera hoja verdadera, plántula, iniciación del llenado del bulbo, máximo desarrollo vegetativo y terminación del llenado del bulbo. La duración de cada fenofase fue diferente entre tratamientos, pues las plantas bajo coberturas emergieron primero que en el testigo (suelo desnudo) y en el semillero. Para siembra directa, el inicio del llenado del bulbo ocurrió antes que en el transplante; este atraso se relacionó con el estrés causado por el cambio del semillero al lugar definitivo y la adaptación al mismo. En la terminación del llenado del bulbo, los coberturas plásticas negra y gris en siembra directa registraron mayores pesos secos del bulbo, en comparación con el acolchado blanco y el testigo (suelo desnudo). Three polyethylene mulches (black, white and gray) and two planting systems (direct seeded and transplant) were tested in common onion (Allium cepa L.) hybrid Yellow Granex PRR, whit the objective of evaluating the duration of developmental stages. The phenophases established were: Emergence, first true leaf, young plantlet, bulb filling initiation, maximal vegetative development and bulb filling termination. There were differences among planting systems in the duration of phenophases; the least duration occurred with the black and gray polyethylene mulches. The combination of these colored plastics and direct seeding shortened the vegetative cycle in 70 days and the yield per plant was higher than in the white plastic mulch and bare soil.
Formación de mazorcas en diferentes nudos del eje de maíz ICA -V-51O
Laverde Pea Héctor,De la Cruz Ramiro,Rojas Emiro
Agronomía Colombiana , 1986,
Abstract: Con el objeto de estudiar la capacidad biológica de producción de mazorca en diferentes nudos de la planta de maiz ICA -V-51O y determinar la mejora en producción de granos, cuando se efectúa polinización manual, se realizó un ensayo en el Centro Experimental de Tibaitatá en el ano de 1979. Para tal efecto se efectuaron decapitaciones a partir del entrenudo uno hasta el décimo y las mazorcas que fueron apareciendo en los diferentes nudos por efecto "del tratamiento se polinizaban manualmente. Los resultados obtenidos indican que existe capacidad biológica para el crecimiento y desarrollo de mazorcas en nudos donde usualmente no se presentan y que su tama o y grado de acumulación de materia seca difieren en alta proporción de las normales. The biological capacity to produce ears In different nodes on corn plants of the variety ICA V-510 and the improvement in grain production with hand polinization was studied at the Tibaitatá, Agricultural Experimental Station. Decapitation internode were done from the flrst to the tenth node and the ears that come out on the nodes were pollinated by hand. The results showed a biological capacity of the plants to grow ears on nodes where normally they do not grow. Size and accumulation of dry matter are very different from normal ears.
STRUCTURALLY CONSTRAINED ROBUST OPTIMAL CONTROL
Pea M,Héctor; Mora C,Sergio;
Ingeniare. Revista chilena de ingeniería , 2006, DOI: 10.4067/S0718-33052006000200011
Abstract: a solution to the robust optimal control problem, subject to local states constraints in the feedback law, is presented. examples with matched and unmatched uncertainty in the system matrix are presented. results obtained through simulation are shown as a means of validating the proposal.
STRUCTURALLY CONSTRAINED ROBUST OPTIMAL CONTROL CONTROL óPTIMO ROBUSTO CON RESTRICCIONES ESTRUCTURALES
Héctor Pea M,Sergio Mora C
Ingeniare : Revista Chilena de Ingeniería , 2006,
Abstract: A solution to the robust optimal control problem, subject to local states constraints in the feedback law, is presented. Examples with matched and unmatched uncertainty in the system matrix are presented. Results obtained through simulation are shown as a means of validating the proposal. Se presenta una solución al problema del control óptimo robusto, sujeto a una ley de control con restricciones de realimentación local de estados. Se muestran los resultados obtenidos por simulación, como medio de validar la propuesta, para incertezas en la matriz de planta del tipo ajustadas y no ajustadas.
Una caracterización de la democracia mexicana y sus actores políticos: la elección para gobernador del Estado de México, 2005
Héctor Zamitiz,Irma Pea León
Revista mexicana de ciencias políticas y sociales , 2006,
Abstract: En este artículo, los autores analizan uno de los procesos electorales más importantes del país antes del presidencial del 2006: el del Estado de México. Los autores consideran estas elecciones como un reflejo de la democracia mexicana así como de sus limitaciones: campa as sumamente costosas donde el financiamiento privado rebasa considerablemente al público; instituciones electorales débiles incapaces de guiar confiablemente el proceso electivo; desacreditación de los partidos políticos ante la opinión pública; inequidad competitiva entre ellos; estrategias de promoción del voto inadecuadas; abstencionismo; falta de supervisión de gastos de campa a y discrepancias entre los gobiernos local y federal en cuanto a la resolución de conflictos pre y post electorales.
Efecto del anabólico acetato de trembolona sobre el crecimiento de Carassius auratus (Pisces: Cyprinidae)
Mara?ón Herrera, Samuel;Tijera Demesa,ctor;Salgado Zamora, Héctor;Maya Pea, Eduardo;
Hidrobiológica , 2008,
Abstract: the anabolic efficiency of steroid trenbolone acetate was evaluated in 60 days old juveniles of carassius auratus. fish were exposed during 120 days to steroid at a dose of 300 mg/kg food. total length, standard length, height and weight were registered every two weeks. the benefit of the steroid was characterized with a model that relates the weight as a function of time, coupled to other two models: one where size is related with time and an alometric one which correlates weight with size. the models showed that growth of steroid treated fish was superior to that of untreated (control) fish, differing significantly (p <0.001), while the alometric model for each treatment, indicated a similar growth (p>0.05). analysis of the variability of the three models demonstrated that the estimates adequately described the growth. this was further confirmed by the determination coefficient (r2) that fluctuated between 72.9 and 93.5% and by the distribution analysis of size and weight by means of box plots. it was concluded that application of the steroid trenbolone acetate to carassius auratus was successful. a survival rate of 100% was registered coupled to an efficient anabolic effect, since a 48.0% gain of biomass and 41.3% increase in size were obtained as compared to the control group.
Efecto del anabólico acetato de trembolona sobre el crecimiento de Carassius auratus (Pisces: Cyprinidae) Anabolic effect induced by trenbolone acetate steroid on the Carassius auratus (Pisces: Cyprinidae) growth
Samuel Mara?ón Herrera,ctor Tijera Demesa,Héctor Salgado Zamora,Eduardo Maya Pea
Hidrobiológica , 2008,
Abstract: Se evaluó la eficiencia anabólica del esteroide acetato de trembolona en juveniles de Carassius auratus de 60 días de edad, expuestos durante 120 días a dosis de 300 mg/kg de alimento. Cada dos semanas se registraron las siguientes biometrías: longitud total, longitud patrón, altura y peso. El beneficio del esteroide se caracterizó con un modelo que relacionó el peso en función del tiempo, acoplado a otros dos modelos: uno en donde se relaciona la talla con el tiempo y otro alométrico, que relacionó el peso con la talla. Los modelos estimados mostraron que el crecimiento de los peces tratados con el anabólico fue superior al de los peces del testigo y difieren significativamente (p<0.001), mientras que los modelos alométricos para cada tratamiento indicaron un crecimiento similar (p>0.05). El análisis de la variabilidad de los tres modelos demostró que las estimaciones describieron en forma adecuada el crecimiento, así lo confirma el coeficiente de determinación (r2) que fluctúa entre el 72.9 y 93.5% y el análisis de la distribución de la talla y el peso con diagramas de caja. Se concluye que la aplicación del acetato de trembolona en Carassius auratus fue exitosa, al registrarse una sobrevivencia del 100% y funcionar como un eficiente agente anabólico, ya que se obtuvo una ganancia de biomasa del 48.0% y de talla del 41.3%, con respecto al testigo. The anabolic efficiency of steroid trenbolone acetate was evaluated in 60 days old juveniles of Carassius auratus. Fish were exposed during 120 days to steroid at a dose of 300 mg/kg food. Total length, standard length, height and weight were registered every two weeks. The benefit of the steroid was characterized with a model that relates the weight as a function of time, coupled to other two models: one where size is related with time and an alometric one which correlates weight with size. The models showed that growth of steroid treated fish was superior to that of untreated (control) fish, differing significantly (p <0.001), while the alometric model for each treatment, indicated a similar growth (p>0.05). Analysis of the variability of the three models demonstrated that the estimates adequately described the growth. This was further confirmed by the determination coefficient (r2) that fluctuated between 72.9 and 93.5% and by the distribution analysis of size and weight by means of box plots. It was concluded that application of the steroid trenbolone acetate to Carassius auratus was successful. A survival rate of 100% was registered coupled to an efficient anabolic effect, since a 48.0% gain of biomass
Temperature Inversions, Meteorological Variables and Air Pollutants and Their Influence on Acute Respiratory Disease in the Guadalajara Metropolitan Zone, Jalisco, Mexico  [PDF]
Hermes U. Ramírez-Sánchez, Mario E. García-Guadalupe, Héctor H. Ulloa-Gódinez, ángel R. Meulenert-Pea, Omar García-Concepción, Jaime Alcalá Gutierrez, Sarahi J. Lizarraga Brito
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.48A1016
Abstract:

The presence of temperature inversions (TI), concentration of air pollutants (AP) and meteorological variables (MV) affect the welfare of the population, creating public health problems (acute respiratory diseases ARDs, among others). The Guadalajara Metropolitan Zone (GMZ) experiences high levels of air pollution, which associated with the presence of temperature inversions and meteorological variations is conducive to the incidence of ARDs in children. The aim of this work is to evaluate the TI, MV, AP and their influence on the ARDs in children under five years in the GMZ from 2003 to 2007. In this period, the moderate and strong TI are the most frequent presenting from November to May. The AP shows a variable behavior during the year and between years, with the highest concentration of particles less than 10 microns (PM10), followed by ozone (O3), nitrogen dioxide (NO2), nitrogen oxides (NOX), carbon monoxide (CO) and sulfur dioxide (SO2), the most affected areas are the southeast of the GMZ. Annual arithmetic mean is 213,510 ± 41,209 ARDs consultations. The most important diseases are acute respiratory infections (98.0%), followed by pneumonia and bronchopneumonia (1.1%), asthma and status asthmaticus (0.5%) and streptococcal pharyngitis and tonsillitis (0.4%). Months with most inquiries were from October to March, mainly

EFECTO DEL USO DE RECUBRIMIENTOS SOBRE LA CALIDAD DEL TOMATE (Lycopersicon esculentum mill)
AMAYA,PAOLA; PEA,LORNA; MOSQUERA,ANDRéS; VILLADA,HéCTOR; VILLADA,DORA;
DYNA , 2010,
Abstract: this study evaluated the effect of the native cassava starch solution (manihot esculenta crantz) and commercial wax application on the firmness, rate of breathing, degrees brix and tomato ph (lycopersicom esculentum mill) to room temperature, through an experimental design completely at random with 3 replications and 3 repetitions, the results were submitted to a variance analysis with a probability of 95%; the significantly different average values were compared using the test of dunnet, for a probability of 95%. there were no significant differences in the evolution of the rate of breathing, degrees brix and titleable acidity (pf of 0,26, 0,48 and 0,28 respectively) whereas if there were it, in the firmness (pf of 0,045), where the tomatoes covered with commercial wax showed a greater firmness and a lower rate of breathing that the fruits covered with the starch solution and the witness.
Genotipos de rotavirus aislados de ni?os chilenos con gastroenteritis atendidos en dos hospitales públicos: variantes virales circulantes en un país con uso limitado de vacunas anti-rotavirus
Lucero,Yalda; Mamani,Nora; Cortés,Héctor; Pea,Alfredo; Vergara,Rodrigo; O'Ryan,Miguel;
Revista chilena de infectología , 2012, DOI: 10.4067/S0716-10182012000200004
Abstract: background: rotavirus is the main cause of severe gastroenteritis (ge) in children. two vaccines currently available have proven efficacy against the predominant genotypes. rotavirus genotypes vary both geographically and/or temporally. genotype surveillance is important to monitor trends associated or not with vaccine use. aim: to update information on rotavirus genotypes circulating in two main cities of chile. methodology: between may 2009-march 2010, children < 5y of age receiving medical care for ge in two large hospitals were recruited; none of these children had received rotavirus vaccine previously. epidemiological information was recorded in an ad-hoc form and stool samples were collected for rotavirus detection by a commercial elisa. genotyping was performed by semi-nested rt-pcr. results: a total of 296/967 samples (31%) were positive for rotavirus, with a peak in november/ december mostly in children 7-24 months old (67%). g9p[8] was the predominant genotype (76%), followed for g1p[8] (6%) and g2p[4] (6%) in both cities. conclusions: rotavirus caused one third of ge requiring emergency room care and/or hospitalization, mostly in children within an age range susceptible to benefit from rotavirus vaccines. g9p[8], a genotype against which rotavirus vaccines have demonstrated high efficacy, was by far the most frequent rotavirus variant. continued surveillance in chile is crucial for providing background information on disease burden and strain diversity before the introduction of rotavirus vaccines.
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