Tecnología educativa radiofónica en la frontera colombo-venezolana a mediados del siglo XX

Se establecen los orígenes y las diferencias entre la programación radial para la instrucción pública y la educación popular articulada a la estrategia radial nacional de Acción Cultural Popular —ACPO—, que se apoyaba en materiales didácticos multimediales, como locutores, tutores, libros, periódicos, manuales, etc., y fue emprendida desde Colombia hasta la frontera con Venezuela. Los análisis son descriptivos y se demuestra el interés estatal por la educación formal y virtual con apoyo de tecnologías remplazables y adaptables entre sí.This study establishes the origins of and differences between the radio programming for public education and radio programming for popular education articulated by the national radio strategy of Popular Cultural Action (Acción Cultural Popular —ACPO—). This strategy was based on multimedia teaching materials, such as speakers, tutors, books, newspapers, and manuals, and was implemented across Colombia to the Colombia-Venezuela border. The analyses are descriptive and demonstrate the state’s interest in formal and virtual education with support from replaceable and adaptable technologies

Magnesium sulphate and the development of the common bean cultivated in an Ultisol of Northeast Australia Sulfato de magnésio e o desenvolvimento do feijoeiro comum cultivado em um Ultissolo do Nordeste da Australia

Magnesium applications (MgS0(4).7H(2)0) to achieve 8 and 16 mmol c/cm3 of Mg (324 and 1284 kg of MgS0(4) ha-1) were made on one Ultisol from Australia Northeast to correct Mg deficiency in plants and to verify the optimum level of Mg to grow common bean (Phaseolus vulgaris L). Magnesium was applied together with lime, N, K, Cu, Zn, B, and Mo as calcium carbonate, ammonium nitrate, potassium phosphate, cupric and zinc sulphate, boric acid and sodium molybdate respectively a month before planting and P as phosphoric acid at the planting. The pH reached the equilibrium after six weeks of incubation. Higher electrical conductivity (EC) was observed in soil where Mg was applied to reach 8 mmol c/cm3 in the absence of common bean and 16 mmol c/cm3 when the plant was present. Higher plant height, leaf area, dry matter weight:leaf area ratio and nutrient concentrations were observed in plants cultivated in soils treated with Mg to reach 8 mmol c/cm3 and 16 mmol c/cm3 when the plant was present. The plant top P content was very low but N, Ca and Mg contents can be considered normal for the common bean.<br>Aplicações de sulfato de magnésio (MgS0(4).7H(2)0) para atigir 8 e 16 mmol c/cm3 de Mg (324 e 1284 kg de MgS0(4) ha-1) foram realizadas em um solo Ultissolo com a finalidade de corrigir deficiências de Mg no feijoeiro e verificar o nível de Mg suficiente para cultivar o feijão comum (Phaseolus vugaris L). O magnésio foi aplicado junto com calcário, N, K, Cu, Zn, B e Mo, como carbonato de cálcio, nitrato de amônio, fosfato de potássio, sulfato de cobre, sulfato de zinco, ácido bórico e molibidato de sódio respectivamente, um mês antes do plantio e o P como ácido fosfórico no plantio. O pH alcançou o equilíbrio após seis semanas de incubação. A condutividade elétrica mais alta (CE) foi observada em solo onde o Mg foi aplicado para atingir 8 mmol c/cm3 na ausência e 16 mmol c/cm3 na presença do feijoeiro A altura das plantas , área foliar, relação matéria seca/área foliar e concentrações de nutrientes no tecido foram maiores nas plantas cultivadas em solos tratados com Mg para atigir 8 mmol c/cm3 . O teor de P foi muito baixo mas os de N, Ca e Mg podem ser considerados normais para o feijoeiro comum