Resumen Se presenta un balance de calor del Lago de Zapotlán que fue resuelto numéricamente mediante el método de Runge-Kutta de cuarto orden con un incremento de tiempo de un día. A semejanza de otros lagos tropicales, el presupuesto anual de calor es muy bajo. La temperatura del lago (correlacionada con la radiación atmosférica y la radiación de fondo), la acción del viento (correlacionada con la radiación solar), y los escurrimientos (correlacionados con la radiación atmosférica, la radiación de fondo, la precipitación sobre el lago y la temperatura del lago), producen el mezclado del lago durante las estaciones de invierno, primavera y verano. Pero en el inicio del otoño, al disminuir el flujo neto de calor superficial y terminar las lluvias, el hipolimnión se enfría levemente debido a que esta capa es ocupada por escurrimientos más fríos y más densos. Esta pequeña diferencia térmica provoca que la columna de agua se estratifique de manera inestable. Los episodios alternados de mezclado y estratificado afectan significativamente el ciclo de nutrientes y la dinámica de la cadena alimenticia del lago. | Abstract This paper presents a heat balance for Lake Zapotlán, which was solved numerically using the fourth-order Runge-Kutta method with a step size of one day. Like other tropical lakes, the annual heat budget of Lake Zapotlán is very low. Lake temperature (correlated with both atmospheric longwave radiation and water back radiation), wind strength (correlated with solar shortwave radiation, and runoffs (correlated with atmospheric longwave radiation, water back radiation, precipitation on lake and lake temperature) produce lake mixing during three seasons: winter, spring and summer. When fall begins, as the net surface heat flux diminishes and rainfall ends, the epilimnion is slightly cooled since this layer receives colder, denser runoff. This small difference in temperature causes the water column to stratify in an unstable manner. The alternating episodes of mixing and stratification significantly affect the nutrient cycle and the dynamics of the food chain.

Contaminated water and food are major causes of malnutrition and mortality in the developing world, particularly among children. Infants are most vulnerable to diarrheal illnesses when introduced to fluids and foods as they are weaned from breastfeeding to a mixed diet. There is scant literature about the role of nutrition professionals in addressing this problem. Considerable progress has been made in identifying strategies to prevent diarrhea in children. Strategies include implementing low-technology methods of sanitizing water, emphasizing the benefits of breastfeeding, protecting prepared foods from unclean environments, and educating and motivating food preparers. Resolution of water and food safety problems requires a collaborative interdisciplinary approach among health professionals and involvement of community leaders. Dietetic professionals have the training to empower individuals and communities with skills to create a safe water and food environment.

In the meat industry there are some processes like drying or storage of salted meat products in which the knowledge of water sorption phenomena in salted proteins could be very useful. The sorption and desorption of most salted products is a singular process with three differentiated steps: a(w) < 0.75, a(w) = 0.75 and a(w) > 0.75. SAFES methodology allows the analysis of different elements in a system: the components, phases and states of aggregation in the food during the process to understand the process stages with a suitable level of complexity. It also analyzes the transport functions, chemical reactions and the phenomena occurring during the processing of the product. The aim of this paper is to analyze the sorption phenomena of water in salted proteins using the SAFES methodology for the three different steps of the water desorption process. Salted pork meat isotherms at different three different salt concentrations and three various temperatures were analyzed in order to observe differences between them, in terms of mass transport, reactions, etc. With SAFES methodology, differences in the behaviour of the system, depending on the amount of NaCl added to the pork meat were observed. Differences in mass fluxes were found in relation to temperature and NaCl concentration.

The viscosity profiles of six commercially available food thickeners (Guarcol, Keltrol, Novartis, Nutricia, QuikThik, and Supercol) in water and raspberry cordial were studied in a strain-controlled rheometer at 20 °C. The thickened fluids exhibited a shear-thinning behaviour, and their viscosities were not significantly (p > 0.05) affected by holding time up to 24 h. Irrespective of the thickener and dispersing medium, the viscosity increased as the solids content was increased, as did density and yield stress. Rheological models that best fit the flow data of the thickeners in the dispersing media were recommended. At an assumed shear rate of about 50 s-1 for normal swallowing, predicted and experimental viscosities are not significantly (p > 0.05) different. The recommended models can be used to calculate the weights of the thickener and dispersing medium to achieve a known viscosity of the thickened fluids, match videofluoroscopy fluids and obtain objective classification of the thickened fluids.

Cofie, Olufunke O.; Drechsel, Pay., 'Water for food in the cities: The growing paradigm of irrigated peri-urban agriculture and its struggle in Sub-Saharan Africa', African Water Journal, vol. 1(1), pp.23-32, 2007

Riddell, 'WWF-FAO-IRRI global initiative to improve food security, enhance livelihoods and reduce water conflicts in irrigated rice - a concept note.', International Rice Commission Newsletter 56(2007): 87-93.