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Copyright of Revista Novedades en Población is the property of Universidad de La Habana, Centro de Estudios Demograficos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The so-called Fourth Industrial Revolution, a visible expression of current technological development, must be analyzed within the framework of the social relations of capitalist production, linked to the logic of the accumulation process and, specifically, to the development of the productive forces. This article aims to explain its relationship with the system of contradictions of capitalism, such as capital and labor, accumulation and consumption, development-destruction of productive forces. [ABSTRACT FROM AUTHOR]

Copyright of Revista Novedades en Población is the property of Universidad de La Habana, Centro de Estudios Demograficos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista ADM is the property of Asociacion Dental Mexicana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Novedades en Población is the property of Universidad de La Habana, Centro de Estudios Demograficos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Novedades en Población is the property of Universidad de La Habana, Centro de Estudios Demograficos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Avances is the property of Instituto de Informacion Cientifica y Tecnologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemical composition of essential oil of white basil, grown with different nitrogen levels it was studied by gas chromatography-flame ionization detector (GC/FID) and gas chromatography coupled to mass spectrometry (GC/MS). The extraction of the essential oil was carried out to samples of fresh and dry leaves, being obtained a significant decrease in the yield and in the content of certain compounds such as the eugenol in the dry samples. The results also show that soil enrichment with nitrogen doesn't have significant effect on the yield or the chemical composition of essential oil. [ABSTRACT FROM AUTHOR]

Copyright of Revista Novedades en Población is the property of Universidad de La Habana, Centro de Estudios Demograficos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The determination of the rate expressions of the acid hydrolysis of sugarcane bagasse using sulfuric acid, obtaining the approximate kinetic models is presented. For the experimental design to acid pretreatment a 2² factorial design was elaborated, varying the reaction temperature (175-185 °C) and the sulfuric acid concentration (0-1.25%). For acid pretreatment a 2³ factorial design was elaborated, varying the reaction temperature (175-195°C), ethanol concentration (10-30 %) and NaOH concentration (1.5-3.0%). For the determination of the rate expressions the differential method of data analysis is applied through of least squares technique. The values of activation energy in reactions of xylose liberation in the acid pretreatment and lignin liberation in basic are determined and compared with those reported in the literature. The influence of the acid concentration variation is studied, as well as the temperature variation through Arrhenius equation. [ABSTRACT FROM AUTHOR]

Copyright of TURyDES is the property of TURYDES and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the research is to analyze the behavior of the safety factor of the upstream slope in earth dams, given the variation in the speed of the transient flow associated with rapid release phenomena. Three case studies of earth dams are presented: La Ruda, Canasí and Jaruco, located in the Mayabeque province. For the execution of the models, the SEEP/W and SLOPE/W tools of the GeoStudio 2018 program are used and the Morgenstern-Price method is used to obtain the safety factor. The analysis is performed for the estimated characteristic curve and for the resulting hydraulic conductivity curve using the Fredlund & Xing method. The fundamental results show a reduction of the factor of safety associated with the speed of transient water flow for all the cases analyzed. [ABSTRACT FROM AUTHOR]

Introduction: Steel foundries are significant pollution sites with manual molding and demolding processes, therefore technology has moved on to molding using self-fragrance resins. In this paper, the Life Cycle Analysis (LCA) methodology is applied to evaluate the environmental impacts in a foundry process subject to this technological investment. Objetive: To evaluate the environmental impact of a technological proposal in the molding stage in a steel foundry. Materials and Methods: The input and output flows of the mixtures of sand, gases and solid waste in the traditional molding and chemical molding processes for the production of one ton of steel, as a functional unit, were evaluated and inventoried. SimaPro 8.0 software was used to obtain LCA results. Results and discussion: The results demonstrate the economic and environmental feasibility of chemical molding. In the analysis, it was verified that the return sand is the raw material with the greatest benefit to the impact categories, favoring from climate change to human health and limiting the formation of particles that affect health, ecosystems and natural resources. Conclusions: The LCA methodology quantifies the environmental impacts of steel production and justifies the economic-environmental feasibility of chemical molding, verifying that the return sand is the raw material with the greatest contribution to the impact categories and, as an avoided product that is recycled, favors in the new technology the environmental and damage categories. [ABSTRACT FROM AUTHOR]