Since the 1980s gold mining in Madre de Dios, Perú has been the main deforestation driver generating severe socioeconomic and ecological impacts. The present research quantifies this activity in 2000 and 2017 by decision tree algorithms applied on a supervised classification of satellite images from LANDSAT 5 and LANDSAT 8 sensors. Results reveal an increase of 47 657,43 ha of deforestation due to gold mining between 2000 and 2017. Categorized areas showed an increase of 42,52% (35 183,45 ha), with the greatest impact on the native communities, concessions for reforestation and buffer zones of Protected Natural Areas. It is worth mentioning that there were 1 139,77 ha by 2000 that presented mining activity and were recovered by 2017. Validation by experts confirmed up to 93% of the detections with Kappa index. Decision tree methodology is direct, with quick processes and accurate result...

In this research work has been synthesized and characterized by chemical route monometallic and bimetallic nanoparticles Core / Shell (Au / Ag), using two-step method involving the preparation of a solution of nuclei formed by gold nanospheres and its union with the armor formed by silver nanospheres; to this, the final size of the nanostructure, intimately dependent kernel size for that matter studied and experimentally examined the influence of parameter variation in the synthesis process._x000D_ It basically studied the influence of synthesis parameters on the gold nucleus, then it choose the best conditions and make the coating and produce silver bimetallic nanostructures. Variations were such as: Method of synthesis of the nanosphere, temperature stabilizing cetyltrimethylammonium bromide (CTAB) 65, 75, 85 and 95 °C, precursor Origin of chloroauric acid (HAuCl4) Stabilizer Type hom...

En este trabajo se ha evaluado el efecto de la temperatura (65, 75, 85 y 95 °C) y el tipo de homogenización (agitación ultrasónica y agitación magnética) en la disolución del bromuro de cetiltrimetilamonio (CTAB), empleado como estabilizante en el proceso de síntesis de nanoesferas de Au por el método de química húmeda. Como agente reductor se ha utilizado borohidruro de sodio (NaBH4). El entendimiento y el control de los diferentes parámetros experimentales durante la síntesis, son la clave para una exitosa fabricación de nanoesferas de Au. Los patrones de difracción por rayos X (DRX) mostraron los picos (111) y (200) característicos del oro a las temperaturas de 75, 85 y 95 °C. Los espectros de absorbancia óptica muestran picos en 528, 527 y 537 nm a las temperaturas de 75, 85 y 95 °C respectivamente, típicos de las nanoesferas de oro, cuyas intensidades se incremen...

Environmental contamination by heavy metals represents a serious problem for humans and the ecosystem due to its degree of toxicity, which is why it is necessary to have treatment alternatives for its disposal. The bioremediation process of the lead (II) and cadmium (II) metals was carried out; through the use of native fungi isolated from the oxidation pool of the metallurgical laboratory of the National University of San Agustín, Arequipa -Peru; in Sabouraud dextrose and potato dextrose broth culture media, the fungal strains were cultivated to carry out the lead (II) and cadmium (II) removal tests, a batch system was used and the removal percentage was determined. Rhizopus spand Aspergillus nigerwere isolated and identified; in the removal tests it was determined that Rhizopus spwas the strain that most removed the lead (II) in 86.39 %, cadmium (II) in 69.23 % and the mixture in 74.8...