Análisis del comportamiento de la región F sobre Tucumán durante un ciclo solar

Se analizan datos del sondador ionosférico de Tucumán (26,9°S; 65,4°O) correspondientes al intervalo julio 1957 - diciembre 1970 abarcando algo más de un período completo de actividad solar, siendo foF2 y h’F los parámetros usados a fin de determinar variaciones estacionales y seculares. Se compara el comportamiento diario de Tucumán con el de Buenos Aires (34,5°S; 58,5°0) en 3 años diferentes, uno de máxima actividad solar, uno de actividad solar media, y uno de baja actividad solar. Se efectúa un análisis de Fourier con el fin de calcular más rigurosamente la magnitud de las diversas componentes armónicas. La correlación entre foF2 y Rz adquiere valores muy elevados.Data from the ionospheric sounder of Tucumán (26,9°S; 65,4°O) corresponding to the period July 1957 - December 1970, which is longer than a complete period of solar activity, are analized. In order to determine the seasonal and secular variations, foF2 and h’F are used as parameters. The daily behaviours of Tucumán and Buenos Aires (34,5°S; 58,5°0) for high, middle and low solar activity conditions taken for a period of one year for each case, are compared. A Fourier analysis is also made in order to calculate the magnitudes of the different harmonic components. High values of the correlation between foF2 and Rz have been obtained.Asociación Argentina de Geofísicos y Geodesta

Evidencia de la presencia de la garganta de densidad electrónica en los registros de los sondadores de la red sudamericana

La aparición de la garganta de latitud media en la concentración electrónica ionosférica, ha sido generalmente observada con registros de la ionosfera de tope. El análisis de los datos proporcionados por la red sudamericana de sondadores de superficie, lleva en forma evidente a la conclusión de que esa garganta también se presenta a latitudes menores que la de Puerto Stanley, correspondientes a valores del parámetro de cana L menores que los encontrados para la garganta "vista" desde satélites en otras regiones del globo terrestre. Asimismo, es clara la presencia de un "pedestal" de incremento de ionización, más allá de la garganta, pero a latitudes aún aleja das del óvalo auroral. Se atribuyen ambos procesos y su discrepancia con otros resultados, en cuanto a ubicación, a la presencia de la anomalía magnética sudamericana.The appearance of the middle latitude trough on the ionospheric electron concentration, has been generally observed with topside ionosphere records. The analysis of data provided by the South American network of surface sounders suggests, in an evident way, that the trough is also present at lower latitudes than Pt. Stanley cor responding to L-shell parameter values smaller than those found for the trough "seen" from satellite heights, for other regions of the terrestrial globe. Likewise, the presence of a "pedestal" of increased ionization is clear, beyond the trough, but at latitudes still somewhat distant from the auroral oval. Both effects, the trough and the pedestal at lower latitudes than "normal", could be justified by the existence of the South American magnetic anomaly.Asociación Argentina de Geofísicos y Geodesta

Evidencia de la presencia de la garganta de densidad electrónica en los registros de los sondadores de la red sudamericana

La aparición de la garganta de latitud media en la concentración electrónica ionosférica, ha sido generalmente observada con registros de la ionosfera de tope. El análisis de los datos proporcionados por la red sudamericana de sondadores de superficie, lleva en forma evidente a la conclusión de que esa garganta también se presenta a latitudes menores que la de Puerto Stanley, correspondientes a valores del parámetro de cana L menores que los encontrados para la garganta "vista" desde satélites en otras regiones del globo terrestre. Asimismo, es clara la presencia de un "pedestal" de incremento de ionización, más allá de la garganta, pero a latitudes aún aleja das del óvalo auroral. Se atribuyen ambos procesos y su discrepancia con otros resultados, en cuanto a ubicación, a la presencia de la anomalía magnética sudamericana.The appearance of the middle latitude trough on the ionospheric electron concentration, has been generally observed with topside ionosphere records. The analysis of data provided by the South American network of surface sounders suggests, in an evident way, that the trough is also present at lower latitudes than Pt. Stanley cor responding to L-shell parameter values smaller than those found for the trough "seen" from satellite heights, for other regions of the terrestrial globe. Likewise, the presence of a "pedestal" of increased ionization is clear, beyond the trough, but at latitudes still somewhat distant from the auroral oval. Both effects, the trough and the pedestal at lower latitudes than "normal", could be justified by the existence of the South American magnetic anomaly.Asociación Argentina de Geofísicos y Geodesta

Leucaena leucocephala cv Perú in Association with Graminaceae in Dryland Conditions for Final Bovine Fattening Stage

To evaluate the factors that affect efficiency in a Leucaena leucocephala cv Perú association, with pastures for bovine fattening, 22 Zebu fattening cycles were studied on a farm of the Rectangulo Livestock Company, in Camagüey, Cuba, between 2002 and 2012. The local soil is brown without carbonates. The climate is tropical humid, and the annual precipitation average is 1 183mm. The factors evaluated were food balance, duration of the fattening cycle, and quantity of animals/cycle. The daily weight gain and expenses/income per operation were also analyzed. The pasture and Leucaena percentages were determined by plant counts. Food balances were estimated. The final value of the population of Leucaena cv Perú was 93% (P <0.05), with an increase in common Bermuda grass and other pastures. Short duration tests showed much higher gains (P <0.05), with values above 1.0 kg/animal/day. The number of animal/cycle (P <0.05) produced higher gains with fewer animals. Forest-grazing in association with Leucaena leucocephala cv Perú-graminaceae under dryland conditions produced mean daily gains above 0.800 kg/animal/day in the final stage of fattening bulls, based on food balances with adequate biological and economic results. The best behavior was observed in the shortest cycles, where the highest final weight/animal values were achieved, with fewer expenses and higher income

Bio-economic Impact of Strategic Changes in Murrah River Buffalo Management

The aim of this paper was to evaluate the effects of changes in the strategy to manage the bio-economic efficiency of a Murrah Buffalo production system in the province of Camagüey, Cuba, located 21º north and 77º west, 217 meters above sea level. The climate is tropical humid (Aw) of plains. The mean annual precipitations were 1 180 mm (71% between May and October), the temperatures were between 24 and 29 °C. The soil is brown, without carbonates, and brown-red fersiallitic. The system comprises 5 100 ha and has 536 workers/year. A strategy to introduce management changes in agro-technical, food, reproductive, replacement, health, salary policy, and training was implemented as part of an innovation package with a systemic and participatory approach. The evaluation lasted eight years, and it was critical to increase dairy production in more than 200 000 kg/year in 2012, in comparison to 2004, with improvements in natality and reduction of operational expenses of the system. It was concluded that the strategy had a determining effect on the system's indicators

Effects of Milled Maize Stalks on the Productive Response of Grazing Dairy Cows.

The productive response of grazing dairy cows was evaluated, using milled corn stalks in the diet. The study was developed in two different settings, in Ecuador (Costa and Sierra regions). On the coast farm (29.1 ha), cows grazed on Bermuda grass (Cynodon nlemfuensis) and Guinea grass (Panicum maximum) with several types of legumes (Lysicarpus, Centrosema, Desmodium, Galactia), supplemented with corn stalks cv. INIAP 125. The animals received 0.46 kg beginning at 3 kg, and milled maize stalks in 30 and 28-day periods, respectively (M-30 and M-28), and control without stalks for 36 days (M-0). The farm in the other region (14.2 ha) had 23 cows grazing on Kikuyo grass (P. clandestinum) and ryegrass-white clover (L. perenne and whole maize stalks and T. (60-70% ripe grain), at a rate of 18 kg green/cow/day for 48 days; and balanced supplement, at a rate of 0.5 kg/ milk liter, after the fourth kilogram, along with minerals. In both cases the forage had effects (P < 0.05) on cow response. In the Sierra area, the increase was 1.68 kg/cow, and in the coast, it was 1.1 and 2.5 kg/cow). Maize stalks served as a nutritional complement for poorly consumed grass areas in both regions; milk production/animal was increased, and the costs were reduced

Leucaena leucocephala cv Perú asociada con gramíneas en secano para ceba final bovina

To evaluate the factors that affect efficiency in a Leucaena leucocephala cv Perú association with pastures for bovine fattening, 22 Zebu fattening cycles were studied on a farm of the Rectángulo Livestock Company, in Camagüey, Cuba, between 2002 and 2012. The local soil is brown without carbonates. The climate is tropical humid, and annual precipitation averages 1 183 mm . The factors evaluated were, food balance, duration of the fattening cycle, and quantity of animals/cycle. The daily weight gain and expenses/income per operation were also analyzed. The pasture and Leucaena percents were determined by plant counts. Food balances were made. Leucaena cv Perú reached final values of 93 % (P < 0.05) with an increase in common Bermuda grass and others. Short duration tests showed much higher gains (P < 0.05), with values above 1.0 kg/animal/day. The number of animal/cycle (P < 0.05) produced higher gains with fewer animals. Forest grazing in association with Leucaena leucocephala cv Perú-graminaeae in drylands produced mean daily gains above 0.800 kg/animal/day in the final stage of fattening bulls, according to food balances with adequate biological and economic results, and the best behavior in the shortest cycles, where the highest final weight/animal values were achieved, with fewer expenses and higher income.Con el objetivo de evaluar factores que afectan la eficiencia en una asociación de Leucaena leucocephala cv Perú con pastos para ceba final de bovinos, se analizaron desde el 2002 al 2012, 22 ciclos de ceba de toros Cebú en una finca de la Empresa Pecuaria Rectángulo de ceba en Camagüey, Cuba. El suelo es Pardo sin Carbonatos. El clima es tropical húmedo (Aw) y precipitación anual de 1 183 mm . Los factores evaluados fueron: balance alimentario, duración de ciclo de ceba y cantidad de animales/ciclo. Se analizaron índices de ganancia diaria de peso, gastos e ingresos por operación. Se determinaron los por cientos de pastos y Leucaena por conteo de plantas. Se realizaron balances alimentarios. Leucaena cv Perú alcanzó valores finales del 93 % (P < 0,05) en su población, con incremento de Guinea común y otros pastos. Las pruebas de corta duración logran ganancias muy superiores (P < 0,05) con valores por encima de 1,0 kg/animal/día. El número de animales/ciclo afectó (P < 0,05) por mayores ganancias con menos animales. La tecnología de silvopastoreo con asociación de Leucaena leucocephala cv Perú-gramíneas en secano, permitió obtener ganancias medias diarias por encima de 0,800 kg/animal/día en toros de ceba final evaluadas por balances alimentarios con resultados biológicos y económicos muy adecuados y el mejor comportamiento para los ciclos más cortos, donde se obtuvieron los mayores pesos finales/animal, con menos gastos por suplementos y mayores ingresos

Efecto de la inclusión del forraje de maíz molido en la respuesta productiva de vacas lecheras en pastoreo.

Se evaluó la respuesta productiva de vacas lecheras en pastoreo al incluir forraje de maíz molido en su dieta. El estudio se realizó en dos ambientes diferentes de Ecuador (Región Costa y Sierra). En la costa, en una finca de 29,1 ha,las vacas pastaron asociaciones de estrella (Cynodon nlemfuensis) y saboya (Panicum máximum) con leguminosas devarios géneros como Alysicarpus, Centrosema, Desmodium, Galactia, suple-mentadas con forraje de maíz cv. INIAP 125. Los animales recibieron 0,46 kg a partir del tercer kilogramo, y forraje de maíz molido en períodos de 30 y 28 días, respectivamente (M-30 y M-28) y control sin forraje por 36 días (M-0). En la otra región, la propiedad tenía 14,2 ha y 23 vacas en ordeño; estas pastaron asociaciones de kikuyo (P. clandestinum) y ryegra-sstrébol blanco (L. perenne y T. repens) y forraje de maíz planta completa (60 a 70 % grano maduro), a razón de 18 kg verde/vaca/día durante 48 días, y balanceado a razón de 0,5 kg/l de leche después del cuarto kilogramo y minerales. El forraje influyó en ambos casos (P < 0,05) en la respuesta de las vacas; para la zona de la sierra el incremento fue de 1,68 kg/vaca de aumento en la leche y en la costa el aumento fue entre 1,1 y 2,5 kg/vaca. El forraje de maíz complementó nutri-cionalmente las asociaciones bajo pastoreo en ambas regiones, incrementó el rendimiento lechero/animal y redujo los costos.Effect of Ground CornStalks on the Productive Response of Dairy Grazing Cows ABSTRACTThe productive response of dairy grazing cows using ground cornstalks was assessed. The study was developed in two different Ecuadoran settings (Costa Region and Sierra). At the Costa, on a 29.1 ha farm, the cows grazed on star clusters (Cynodon nlemfuensis) and panic grass(Panicum máximum), with legumes of different genera, such as Alysicarpus, Centrosema, Desmodium, Galactia, supplemented with corn stalks, cv. INIAP 125. The animals received 0.46 kg from the third kg onward, and ground corn stalks in 30- and 28- day periods, respectively (M-30 and M-28), and a control group without stalks for 36 days (M-0). In another region, the estate had 14.2 ha and 23 milking cows, grazing on clusters of West African pennisetum (P. clandestinum) and ryegrass white clover (L. perenne and T. repens) and whole corn stalks (60 -70 % ripe grain), at a ratio of 18 kg green/cow/day for 48 days and balanced at a ratio of 0.5 kg/l of milk following the fourth kilogram, and minerals. In both cases, stalks effected (P < 0.05) on cow response. In the Sierra region, the milk yield increase observed was 1.68 kg/cow, and in the Costa region, it was between 1.1 and 2.5 kg/cow. Corn stalks meant nutritional supplementation to grazing clusters in both regions, increased milk/animal yields, and cost reductions

Suplementación con Norgold + miel urea al 3 % de bovinos cebú en crecimiento-ceba en sistema de pastoreo en época de seca.

Con el objetivo de determinar el alcance productivo en bovinos cebú al utilizar como suplemento Norgold + mela-za-urea al 3 % durante la etapa de crecimiento-ceba bajo sistema de pastoreo, se emplearon 60 toretes, de iguales pesos y características raciales, conformándose cuatro grupos experimentales; sometido a 9 h diarias de pastoreo, sobre pasto pitilla (Dichantium annulatum) + tejana (Paspalum notatum) de calidad regular; 3 kg de forraje de Penisetum Cuba CT – 115; 1,0; 1,5 y 2,0 kg de Norgold para los grupos I, II, III y IV, respectivamente y sal mineral y agua adlibitum. Se determinó el peso vivo inicial y final, crecimiento absoluto, ganancia media diaria y consumo, así como se estimó el beneficio/costo. Los animales del tratamiento 4 lograron alcanzar 401 kg de peso vivo; es decir, el 47,43 % de su peso respecto al peso vivo inicial en 180 días, y como promedio para todo el período, una ganancia media diaria y conversión de 716,66 g y 10,37 kg de alimento/kg de peso vivo, respectivamente. Se concluye que los tratamientos donde se incluye 2,0 y 1,5 kg de Norgold, respectivamente, lograron ganancias medias diarias y conversión alimentaria superiores (P < 0,05) a los sistemas tradicionales con base de melaza-urea y otros subproductos, así como la producción de carne que se logra permite una relación costo/beneficio positiva, lo cual significa que el sistema es factible, productivo y económico.Norgold Supplementation + Urea Molasses (3 %) for Pasture Fattening Growing Zebu Bovines in the Dry Season. ABSTRACTWith the objective of determining the productive reach in bovine Cebú when using as supplement Norgol + molas-ses-urea to 3 % during the stage of growth-it feeds low shepherding system, 60 properly uniformed toretes was used as for weight and characteristic racial conforming to subjected four experimental groups at nine daily hours of shepherding, on grass PITILLA (Dichantium annulatum) + Tejana (Paspalum notatun) of regular quality; 3 kg of forage of Penisetum Cuba CT - 115; 1.0, 1.5 and 2.0 kg of Norgold for the groups I, II, III and IV, respectively and salt mineral and it dilutes ad libitum. The weight alive initial was determined and final, absolute growth, daily half gain and I consummate as well as was considered the benefit/cost. The animals of the treatment four were able to reach 401 kg of live weight , that is to say, 47.43 % of their weight regarding the weight live initial in 180 days and like average, for the whole period, a daily half gain and conversion of 716.66 g and 10.37 food kg / kg of weight lives respectively. It concludes that the treatments where it is included 2.0 and 1.5 Norgold kg respectively they achieved earnings daily stockings and conversion alimentary superiors significantly (P ≤ 0.05) to the systems that traditionally have been orchestrated with the help of molasses-urea and the employment of other by-products, as well as the meat production that is achieved allows a relationship positive benefit / cost, that which means that the system is feasible, productive and economic