This research was supported by the Phosagro/UNESCO/IUPAC Partnership in Green Chemistry for Life (Contract ). JCFRR acknowledges the support of 4500245048FONDECYT and the World Bank (Contract 106-2018).The participation of GL was possible through the Real Life Experience (RLE) program at UTEC. Karinna Visurraga is thanked for administrative support.

Leaching of polymetallic sulfides is often challenging due to the complexity of these systems. The main issues are related to the formation of surface by-products or to the presence of different metals that require a greater consumption of chemicals compared to that needed to extract the target metal during leaching. This latter case is followed in the present work using X-ray photoelectron spectroscopy (XPS) during the leaching of a silver-containing polymetallic (Mn-Fe-Pb) sulfide under three different cyanidation procedures: (1) conventional leaching, (2) ultrasound-assisted leaching, and (3) leaching of a sample pretreated in alkaline media. In all cases, leaching results in the build-up of Pb compounds (oxides/hydroxides) on the surface of the minerals, suggesting a mechanism in which Pb is first leached by hydroxide and cyanide and later is re-adsorbed as an external layer on the m...

To identify characteristics of reproductive health in a group of teenagers pregnant. DESIGN: Transversal descriptive study. Materil AND METHODS: 400 edolescentes randomly chosen (13-18 years), gestation to term, without mental nor physical alterations, performing one interview previously validated. RESULTS: Mean age 17 ± 1.56 (13-18) years, menarche 13 ± 1.7 (8-18) years, first sexual intercourse 15 ± 1.34 years, with the father of the newborn (75.2%) 2.75% rape (11 cases). Reason for first intercourse: shared with partner (43.7%), then referring fear 18%, shame 14.7%, repentance 10% desire. 87% reported sexual partners, 13% from 2 to 5. 54.5% had no prior information about sexuality, only 6% knew their fertile period, 45% the process of fertility. 27% do not know any method of family planning: 78% know about AIDS and 20.7% ignore about other STDs. CONCLUSIONS: Adolescents with poor k...

To identify characteristics of reproductive health in a group of teenagers pregnant. DESIGN: Transversal descriptive study. Materil AND METHODS: 400 edolescentes randomly chosen (13-18 years), gestation to term, without mental nor physical alterations, performing one interview previously validated. RESULTS: Mean age 17 ± 1.56 (13-18) years, menarche 13 ± 1.7 (8-18) years, first sexual intercourse 15 ± 1.34 years, with the father of the newborn (75.2%) 2.75% rape (11 cases). Reason for first intercourse: shared with partner (43.7%), then referring fear 18%, shame 14.7%, repentance 10% desire. 87% reported sexual partners, 13% from 2 to 5. 54.5% had no prior information about sexuality, only 6% knew their fertile period, 45% the process of fertility. 27% do not know any method of family planning: 78% know about AIDS and 20.7% ignore about other STDs. CONCLUSIONS: Adolescents with poor k...