Apparently healthy preschool children (46 boys, 52 girls) aged 27-50 mo from low socioeconomic conditions who attended daycare centers in Santiago participated in a 14-mo long double-blind zinc supplementation trial. Unlike most previous studies, no additional inclusion criteria such as short stature or slow growth rate were considered. Subjects were pair matched according to sex and age and randomly assigned to two experimental groups: the supplemented group, which received 10 mg Zn/d, and the placebo group. Selected anthropometric, clinical, dietary, biochemical, and functional indexes were determined at the beginning of the study and after 6 and 14 mo of intervention. Actual dietary zinc intake was 66% of the recommended dietary allowance. Height gain after 14 mo was on average 0.5 cm higher in the supplemented group (P = 0.10). The response, however, was different between sexes. Boys from the supplemented group gained 0.9 cm more than those in the placebo group (P = 0.045). No effect was seen in girls. Although no significant differences were observed in the rest of the variables studied, trends (0.05 < P < 0.10) in the supplemented group compared with the placebo group for increased midarm muscle area in boys, improved response to tuberculin, and reduced rates of parasite reinfestation were noted. We conclude that in preschool children of low socioeconomic status, zinc is a limiting factor in the expression of growth potential.

This present study gives an estimation of the time and efficiency in the transformation of pine logs into boards for the manufacturing of pallets in the industry, Haro Madera. Here, the percentage of the wood used and the percentage of sawdust were determined. This was with a yield of 34.936% in the processing of the logs, 43.29% into square posts, and 15.08% in the direct transformation of the logs into boards. In order to determine the factors that affect the production of pine lumber, the wood was classified by its length, diameter, and shape where it was possible to determine its influence in the production into boards. This, therefore, proves that the qualitative factors are influential in the elaboration of the boards to construct pallets, in terms of time. Also, it was possible to determine that for the manufacture of an American type pallet, it took 10.24 minutes, while the European type pallet took 13.9 minutes. To determine the output per machine, a sampling was used. Here, specific observations were made, dividing working time and non-working time. Wood utilization percentage was low, the production line must be improved, and the logs from different plantations should be classified according to their diameter and shape.

This research was developed to determine the physical and mechanical properties of three forestry species such as: Piptocoma discolor (Kunth) Prusky (Pigüe), Iriartea deltoidea Ruiz & Pav. (Chonta) and Pouteria glomerata (Intachi); thus giving the suitable use to each specie according to their response to the tests. The tests were done at ESPOCH laboratories, using the lab from the irrigation experimental center of the Natural resources faculty for checking the physical properties of humidity and density. The lab from Material resistance of the mechanical Faculty was used to check the mechanical properties. This study is quite important due to the lack of information researched on all the specie properties. One example would be the Pigüe case, which has been used for fruit boxing, the same that presents better qualities than Intachi and it can be perfectly used in building poles and pillars even at decks because of its light, soft and easy-to-cut wood. The Intachi is an excellent kind of Wood used for floors and the Chonta used for bridges and outsides because of its hard and strong wood.