Los números reales y ciertos resultados de aproximación

El objeto de esta nota es estudiar la distribución de ciertos conjuntos de números reales que poseen cierta estructura algebraica. Antes de abordar el tema específico que nos ocupará, daremos una breve introducción histórica

Un teorema de Kronecker de densidad en Rn

En esta nota generalizaremos algunos resul tactos de un articulo anterior (R. E. M. Vol. 7. 1). La diferencia esencial es que trabajaremos en n dimensiones, obteniendo resultados de aproximación "simultánea" de números reales. El resultado principal es el teorema (13)probado por el matemático alemán Kronecker. Este teorema es sumamente importante, en particular para la construcción de ejemplos en distintas ramas de la matemática

Reduction of pesticide use in fresh-cut salad production through artificial intelligence

Incorrect pesticide use in plant protection often involve a risk to the health of operators and consumers and can have negative impacts on the environment and the crops. The application of artificial intelligence techniques can help the reduction of the volume sprayed, decreasing these impacts. In Italy, the production of ready-to-eat salad in greenhouses requires usually from 8 to 12 treatments per year. Moreover, inappropriate sprayers are frequently used, being originally designed for open-field operations. To solve this problem, a small vehicle suitable for moving over rough ground (named “rover”), was designed, able to carry out treatments based on a single row pass in the greenhouse, devoted to reduce significantly the sprayed product amount. To ascertain its potential, the prototype has been tested at two growth stages of some salad cultivars, adopting different nozzles and boom settings. Parameters such as boom height, nozzle spacing and inclination, pump pressure and rover traveling speed were studied. To assess the effectiveness of the spraying coverage, for each run several water-sensitive papers were placed throughout the vegetation. Compared to the commonly distributed mixture volume (1000 L/ha), the prototype is able to reduce up to 55% of product sprayed, but still assure an excellent crop coverage