Prólogo

La presente obra de una manera acuciosa, analiza el tema en cuestión desde diferentes ópticas, aristas que corresponden a rubros que van de lo geográfico, cultural, antropológico, sociológico, económico, educativo, psicológico, pasando por lo político. Como es evidente, cuando se analiza un tema desde ópticas tan distintas, se pueden encontrar puntos de coincidencia, pero también distanciamientos, que son el resultado del análisis y las reflexiones al respecto.La sustentabilidad de los ecosistemas, el fenómeno del cambio climático, los problemas de escasez, contaminación y mal uso del agua; son algunas ideas que han marcado las discusiones alrededor del mundo desde los últimos años del siglo XX hasta nuestros días. Internacionalmente, algunos discursos se inscriben en reconocer la importancia del agua como un derecho fundamental del hombre, como es el caso de la Organización de las Naciones Unidas (ONU), el Banco Mundial (BM), los cuales consideran la importancia de la participación del sector privado en la prestación de servicios urbanos, o la visión de la Organización para la Cooperación y el Desarrollo Económico ( OCDE), que también resalta la importancia de hacer uso de los mercados y de sus instrumentos económicos para resolver la problemática de los recursos hídricos.Universidad Autónoma del Estado de México-Unidad Académica Profesional Chimalhuacá

The Effects of Marijuana Decriminalization on Youth

Research suggests that physical and psychological health problems, as well as the inability to perform well academically and professionally, can be attributed to marijuana use, especially when individuals start smoking or consuming at an early age. Cannabis is not a federally legal substance, thus no regulatory agency exists that assures marijuana and marijuana-laced products are efficient and safe for the public. The lack of this substance’s control has lead to the accidental consumption of marijuana edibles by children, which are a population of particular concern along with adolescents due to the drug’s greater negative effect on their developing brain. Opponents also fear that use and crime will incremently increase with legalization. Statistics, however, prove that these beliefs are erroneous. On the contrary, supporters agree that the legalization of marijuana will greatly benefit society, for example, by decreasing crime rates and allowing law enforcement officials to focus on protecting citizens from real dangers. This argument might be accurate. Studies show that in states where marijuana has been decriminalized, delinquency has declined. Although adults in four American states can legally use marijuana recreationally, the drug is far from being licit at the federal level

An Augmented Gravity Model: Factors that Affect the U.S. Sugar Imports from Western Hemisphere Countries

This study analyzes the main factors that affect sugar imports to the United States from western hemisphere producing countries. Important variables such as Free Trade Agreements, production capacity levels and the quota imposed by the United States to the imported sugar will be analyzed under the scope of the gravity model. The estimation of the model is carried out using an OLS analysis. The variables used to create a reliable single-commodity gravity model are: sugar production indicators, distances between the involved countries, population, import quotas, and a set of dummy variables such as FTA (Free Trade Agreements) and border, that augment the model in order to identify and capture the effects of transactional costs and productivity on the sugar industry. The main focus is to assess the extent in which the variables affect sugar imports by the United States. The participation of the United States on international trade makes it essential identifying the FTAs in which they are involved. Some of the FTAs are the North American Free Trade Agreement (NAFTA), The Dominican Republic and Central American Free Trade Agreement (CAFTA-DR), and individual FTAs. On the other hand, the major constraint to U.S. sugar imports are the tariff rate-quotas (TRQ), which are analyzed in order to determine the degree of the effect of this distortion on sugar trade. This research will demonstrate that although the existence of efficient sugar producers and, that FTAs suppose an increase of trade between countries, in the sugar industry, quotas have shown weighting more than any other factor in the U.S. sugar imports

Development and Calibration of a Multi-Zone Model to Predict the Distribution of Contaminant in a Residential Building Using CONTAM Software

The use of computer simulations is a powerful alternative in the Indoor Air Quality (IAQ) study due to the efficient performance and the amount of it is able to obtain. Multi-zone modeling is one of the most popular computing methods for IAQ study, thus can provide the knowledge of indoor airflow, temperature and contaminant concentration distributions. The study was conducted in TX Air House 1 using CONTAM software developed by U.S. National Institute of Standards and Technology (NIST) which is one of the most widely used airflow and indoor modeling program. The model was developed and calibrated to predict the contaminant distribution in residential buildings. In order to validate the results used in this work, statistical tools such as correlation coefficient, normalized mean square error and others were used to evaluate the accuracy of Indoor Air Quality (IAQ) prediction. Flow parameters and HVAC characteristics are the basis for the analysis and understanding of building airflow and tracer gas behavior. Dropping the number of individual flow parameters and tuning in on the HVAC characteristics during calibration, allowed to reduce the error and elevated the accuracy of the model, since the zones have similar airflow dynamics and tracer gas behavior. Wind speed and wind direction could have significant influences in the distribution of the contaminant. The slight variations over time, the small amount of cross contamination between zones, and the physical conditions such as the tightness of the building, were observed to not allow these factors to have a real influence on the distribution of the contaminant

Sidebranching induced by external noise in solutal dendritic growth

We have studied sidebranching induced by fluctuations in dendritic growth. The amplitude of sidebranching induced by internal (equilibrium) concentration fluctuations in the case of solidification with solutal diffusion is computed. This amplitude turns out to be significantly smaller than values reported in previous experiments.The effects of other possible sources of fluctuations (of an external origin)are examined by introducing non-conserved noise in a phase-field model. This reproduces the characteristics of sidebranching found in experiments. Results also show that sidebranching induced by external noise is qualitatively similar to that of internal noise, and it is only distinguished by its amplitude.Comment: 13 pages, 5 figure

Acaparamiento

Si se consideran algunos factores tales como: la densidad poblacional, disponibilidad hídrica, distribución del servicio, cobertura y consumo, es posible observar una importante tendencia a la baja, ello en cuanto a la provisión de agua se refiere, todo ello aunado a las dimensiones del espacio y número de utensilios, mostrarían, sin lugar a dudas un escenario de escasez.en un estudio relativamente cercano, la Comisión Nacional de Agua (CONAGUA, 2004), advierte que en el caso específico de la Ciudad de México, sus habitantes tienen una provisión media de agua (4094 metros cúbicos per cápita anuales).Universidad Autónoma del Estado de México. Unidad Académica Profesional Chimalhuacán