Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Echeverría, Bolívar y Castro, Carlos, Sartre, los intelectuales y la política. Editorial Siglo X X I. Colección Mínima. México, 1968. Primera edición, 108 pp.

Treaties and Alliances of the World. Survey of International Treaties in Force and Communities of States. Keesing's Publications Ltd., Keynsham-Bristol, 1968, VIII, 158 pp.

Tebbel, John, Breve historia del periódico norteamericano. Trad. Enrique F. Gual. Barcelona, UTEHA, 1967, 291 pp. Ilus.

Turner, Frederick C., The Dynamic of Mexican Nationalism, The University of North Carolina Press, Chapel Hill, 1968.

Environmental assets are a source of social, economic and cultural progress in each country, however, they have deteriorated due to human overexploitation and there is widespread concern at the governmental and organizational level in their preservation. Environmental assets provide a variety of goods and services to society, the need to value them as an economic instrument allows to have tangible and monetary elements for adequate conservation plans. The objective of this study was to estimate the economic value of the Calakmul Biosphere Reserve, Campeche, Mexico. It was necessary to analyze factors and indicators of environmental assets of the reserve, study variables that affect the economic value, as well as identify and apply a method for valuation of the reserve. An analysis of institutions and regulations related to the administration, preservation and quantification of environmental assets was presented, where it was identified that there are no specific regulations for the valuation of natural areas as a whole. Regarding the methodological process of valuation of environmental assets, there is no single valuation method, however, the concept of Total Economic Value was applied, which involved direct and indirect uses related to environmental assets, for which, it was necessary to identify benefits that said assets represented and make their economic quantification. Although the value that is concluded with this intervention project is not absolute, it corresponds to a reference value and complies with elements that help to sensitize society in valuing natural resources and compromise the subsistence of future generations.

Beekeeping has stood out as an important economic activity for the Brazilian Northeast, contributing to the generation of family income and work for men in the fields. The objective of this study was to identify the main methods used for beekeeping in Campo Maior, Piauí to evaluate their strengths and weaknesses and improve the economic and agronomic viability. The study methodology involved a qualitative-quantitative approach using semi-structured interviews and forms with ten members of the Association of Campo Maior Beekeepers (APICAM) between July and August 2019. The data was analyzed through descriptive statistics and content analysis, and a SWOT analysis was used (strengths, opportunities, weaknesses and threats). Based on the data obtained, it was identified that beekeeping operations have an average of 2.5 workers, with most family-operated. The ranges of honey production between 251 and 1000 kg in year-1 are highlighted, depending on the productivity values of each hive. The main benefit APICAM members have in the market is higher value product due to superior sustainability and organic production. The main problems with beekeeping is limited management of production costs and fluctuations in the price of honey in the market. To enhance beekeeping in the region there is a need for public initiatives stimulating production and economic efficiency and promoting sustainable organic honey production.

In Mozambique, the province of Manica is a reference in the occurrence and exploitation of alluvial gold. This mineral is currently explored on an industrial and artisanal scale. The extraction of gold consists on the removal of rich and poor sediments. Poor sediments as well as processing waste are discarded on the surface, covering soils rich in minerals and nutrients, leaving these poor to practice farming. Currently, agricultural production in artisanal gold mining sites has been reduced. Thus, the objective of this work was to evaluate the chemical parameters of soils in the areas of mining in relation to fertility for agricultural production, namely pH, Hg, Zn, NPK, MO and CTC. The study was carried out in the localities of Cacárue, Mucurumadze and Penhalonga, where 10 soil sampling points were chosen randomly at depths 0-20 and 20-40 cm in each of the localities, which were then homogenized respectively. These depths were chosen considering that it is the region with the highest concentration of nutrients for food crops. A total of eight samples were collected in each site, four with a depth of 0-20 and four with a depth of 20-40 cm. The results showed that the levels of Nitrogen, Phosphorus and Potassium were low and the pH ranged from 3.99 in Penhalonga to 5.80 in Mucurumadze. These results showed that some of the areas can be reused for agriculture, but for specific crops after soil treatment. Mining ativities in these locations compromise the quality of the soil, with regard to the standards required for agricultural practice.

Irrigation is used as a management strategy in many regions around the world. However, due to the salinity characteristics of the semiarid region, this measure has become increasingly difficult due to the scarcity of good quality water with low levels of salts. One of the factors that can lead to salt stress are crops irrigated with water with high electrical conductivity, reflecting in a soil unfavorable to plant growth. Sunflower is a drought and salinity tolerant crop. In this context, the objective of this work was to evaluate the use of organic residue from marine macroalgae on the production of sunflower plants under two saline conditions (50 or 100 mM NaCl) and control group in substrates containing organic compound from algae or earthworm humus. The use of algae compost was more efficient than earthworm compost under control conditions. Under 50 mM salinity conditions, the results were similar to the use of humus. The use of this residue can be an alternative to commercial fertilizers under controlled conditions or with moderate salinity, minimizing production costs.

Despite the growth of the organic food market in Brazil, these foods remain restricted to a minor part of the population. In this scenario, the short circuits are presented as an alternative to the predominant food distribution model, which is characterized by impersonality and long distances. This paper aims to analyze the motivation of the organic products consumers and this market in Sorocaba (in the state of São Paulo). For this purpose, two methodological procedures were used: an online survey (quantitative approach) and semi-structured interviews (qualitative approach). As results, the consumers habits revealed two different positions: an appreciation of practicality and a search for diversity, both in products and in ways of purchasing them. Because of these choices the consumers alternate between short and long circuits possibilities.

Floodplains were the first deforested areas for agriculture use all over the world. In Brazil these areas can be restored by the growth of guanandi Calophyllum brasiliense, a slow-growing native forest species adapted to flooding. The aims of this study were to: (i) evaluate the taro, Colocasia esculenta, management under two agroforestry systems (AFS) (Simple and Biodiverse) in succession to a reforestation with guanandi, (ii) evaluate the contribution of macronutrients from the green manure Flemingia macrophylla and Sesbania virgata, both managed using pruning for green manure in the respective AFSs, and (iii) the effects on soil nutrients levels compared to monoculture of guanandi (control). The randomized block was designed with eight replication and 216.0 m² plots with four rows of six guanandi trees in each line. In the simple AFS (SAFS), the taro was intercropped with Flemingia and in the biodiverse AFS (BAFS), Sesbania, banana shrub (Musa sp.), edible palm (Euterpe edulis) and fourteen species of native trees were included. Production was evaluated in seasons with high rainfall and water scarcity. With floods the taro has produced around 15 Mg ha-1 of marketable corms in the SAFS and 9 Mg ha-1 in the BAFS, but the drought has made commercial production unfeasible, with no differences between cormels and corms planting. However, enough rhizomes were harvested for a new planting. Flemingia has accumulated 17 Mg ha-1 of fresh matter and Sesbania contributed with 2 Mg ha-1. Soil pH and macronutrient content, especially K, were significantly higher in AFSs areas compared to guanandi monoculture.