El objetivo de la investigación fue cuantificar el aporte que el agua hizo al valor de la producción agrícola bajo la modalidad de riego en México durante el periodo 1980-2017. Para tal fin, con base en la metodología econométrica, se estimó un modelo logarítmico hiperbólico o recíproco logarítmico, pertinente para una función producción cuando se considera solo un insumo mientras los demás permanecen constantes. La variable explicada fue el logaritmo natural del valor de la producción agrícola bajo riego al nivel nacional en pesos constantes de 2013, la variable explicativa fue la inversa del agua suministrada para riego en hectómetros cúbicos; ambas variables fueron I(0). Se comprobó que las regiones hidrológico-administrativas I, II, III, IV, VI, VII y VIII -estados del norte y del bajío del país- concentran el 89.4% del total de la superficie de riego nacional, regiones hidrológico-administrativas, que fueron altamente beneficiadas con las inversiones federales en los distritos y las unidades de riego. Durante el periodo analizado se detectaron dos cambios estructurales: 1) de 1980-1987; y 2) de 2009-2017. Se concluyó que el aporte del agua al valor de la producción bajo riego registró tendencia positiva, en 1980 fue de $0.39 m-3 y para 2017 de $1.92 m-3, para el periodo 1980-1987 de $0.39 m-3, para 1988-2008 de $1.11 m-3, para 2009-2017 de $1.74 m-3. Finalmente, el aporte promedio, del periodo considerado, del agua al valor de la producción bajo riego en México fue de $1.11 m-3. | Abstract The objective of the research was to quantify the contribution that water made to the value of agricultural production under the irrigation modality in Mexico during the period 1980-2017. For this purpose, based on the econometric methodology, a hyperbolic logarithmic or logarithmic reciprocal model was estimated, relevant for a production function when only one input is considered while the others remain constant. The variable explained was the natural logarithm of the value of irrigated agricultural production at the national level in constant pesos of 2013, the explanatory variable was the inverse of the water supplied for irrigation in cubic hectometers; both variables were I(0). It was found that the hydrological-administrative regions I, II, III, IV, VI, VII, and VIII -northern and Bajío states of the country- concentrate 89.4% of the total national irrigated area, hydrological-administrative regions that were highly benefited with federal investments in the irrigation districts and units. During the period analyzed, two structural changes were detected: 1) from 1980 to 1987; and 2) from 2009 to 2017. It was concluded that the contribution of water to the value of irrigated production registered a positive trend, it was $0.39 m-3 in 1980, $1.92 m-3 in 2017, $0.39 m-3 for the period 1980-1987, $1.11 m-3 for 1988-2008, $1.74 m-3 for 2009-2017. Finally, during the period considered, the average contribution of water to the value of irrigated production in Mexico was $1.11 m-3.

Phytoremediation of aquatic plants is a technology for the bioremediation of contaminated waters that is presented as an economical and effective alternative in the extraction of contaminants. Of the great diversity of Panamanian flora, Lemna Minor stands out for its capacity to retain heavy metals and as biomass for the generation of biogas. Due to this, a bio-treatment of wastewater is proposed for the mining industry, implementing phytoremediation to absorb the mercury (Hg) residues generated in its process and anaerobic co-digestion after the extraction of mercury for energy cogeneration. The bibliographic review on the mercury absorption capacity in Lemna Minor and the data collected in the laboratory allowed defining parameters, obtaining as results the reproduction rate of the plant PA=7.78 g/m^2/h , absorption rate of mercury per unit mass of Lemna C_Hglemna=0.28μg/(g h) and the yield for minimum methane production under heavy metal toxicity in Lemna, PBM=132 L/kg.S Extreme conditions of mercury concentrations found in mining regions of Asia of 103 μg/L were considered in which Posada & Arroyave Maya, 2006, verified that under these conditions the reproduction rate of Lemna Minor is not affected. Obtaining an area necessary for the treatment of these conditions of 15.21 hectáreas y un subproducto para la cogeneración de la planta mediante la implementación de codigestión anaeróbica de 156 228 L/h biogás. | La fitorremediación de plantas acuáticas es una tecnología para la biorremediación de aguas contaminadas que se presenta como una alternativa económica y eficaz en la extracción de contaminantes. De la gran diversidad de la flora panameña, se resalta la Lemna Minor por su capacidad de retención de metales pesados y como biomasa para la generación de biogás. Debido a esto, se propone un bio-tratamiento de aguas residuales para la industria minera, implementando la fitorremediación para absorber los residuos de mercurio (Hg) generados en su proceso y la codigestión anaeróbica posterior a la extracción de mercurio para la cogeneración de energía. La revisión bibliográfica sobre la capacidad de absorción de mercurio en la Lemna Minor y los datos recolectados en el laboratorio permitió definir parámetros, obteniendo como resultados la tasa de reproducción de la planta PA=7.78 g/m^2/h , tasa de absorción de mercurio por unidad de masa de Lemna C_Hglemna=0.28μg/(g h) y el rendimiento para la producción de metano mínimo bajo toxicidad de metales pesados en Lemna, PBM=132 L/kg.Se consideraron condiciones extremas de concentraciones de mercurio encontradas en regiones mineras de Asia de 103 μg/L en el que Posada & Arroyave Maya, 2006, comprobaron que bajo estas condiciones la tasa de reproducción de Lemna Minor no se ve afectada. Obteniendo un área necesaria para el tratamiento de estas condiciones de 15.21 hectáreas y un subproducto para la cogeneración de la planta mediante la implementación de codigestión anaeróbica de 156 228 L/h biogás.

Se evaluó el efecto del ozono en fase acuosa para la desinfección de tomates (Lycopersicon esculentum Mill.) cultivar FA-180. Los tomates maduros fueron inoculados con Escherichia coli ATCC 25922 y posteriormente lavados con agua ozonizada bajo dos sistemas de agitación durante 15 y 30 min a concentraciones de ozono disuelto de 0,5 y 1,0 mg/L y se evaluó la concentración del microorganismo en los tomates tratados y no tratados. Se comprobó que el ozono en fase acuosa ejerce un marcado efecto en la desinfección de tomates contaminados, resultando el sistema de lavado con zaranda el más adecuado. Se recomienda una concentración de ozono disuelto de 1 mg/ L y un tiempo de tratamiento de 15 min para lograr un grado de desinfección satisfactorio en tomates maduros. | The aim of this study was to evaluate the effect of the ozoned water for the disinfection of tomatoes (Lycopersicon esculentum Mill.) FA-180. The ripened tomatoes were inoculated with Escherichia coli ATCC 25922 and washed with ozoned water under two systems of agitation during 15 and 30 min in concentrations of dissolved ozone of 0.5 and 1.0 mg/L, and it was evaluated the concentration of the microorganism in the treated and non treated tomatoes. It was demonstrated that ozone in aqueous phase has a marked effect in the disinfection of polluted tomatoes, and the washing system with a lab shaker was the more appropriated. A concentration of dissolved ozone of 1 mg/L and a time of treatment of 15 min are recommended to achieve a satisfactory disinfection in ripened tomatoes.

A banana é uma cultura de grande relevância econômica e socioambiental, com perdas significativas ocorrendo ao longo da cadeia de produção, especialmente na fase de pós-colheita. O uso de ozônio surge como uma alternativa promissora e segura aos tratamentos químicos convencionais para minimizar essas perdas. Este estudo teve como objetivo avaliar os modelos cinéticos da reação do ozônio em água em diferentes temperaturas e determinar a eficácia da imersão em água ozonizada no controle de Colletotrichum musae em bananas, além de analisar os impactos na qualidade do produto durante o armazenamento. Desta forma, foram testados cinco tratamentos na variedade de banana ‘Nanicão’: controle (sem imersão), imersão em água sem ozônio (dois e três ciclos), e imersão em água ozonizada (dois e três ciclos). Cada ciclo durou 15 minutos. Após o tratamento, os frutos foram armazenados por 9 dias a 25 °C e 75% UR. Os resultados mostraram que a maior concentração de ozônio e o tempo de meia-vida mais prolongado (117,6 minutos) foram alcançados a 15 °C. No entanto, na presença de bananas, a meia- vida foi drasticamente reduzida para apenas 0,9 minutos. Não houve efeito significativo do tratamento com água ozonizada no controle da antracnose ou na qualidade das frutas durante o armazenamento. Concluiu-se que, embora a meia- vida do ozônio seja maior a 15 °C, a matéria orgânica presente na banana reduz substancialmente esse tempo, e a imersão em água ozonizada não foi eficaz no controle de antracnose Palavras-chave: musa spp; ozônio; modelos cinéticos; saturação; decaimento; pós- colheita. | Banana is a crop of great economic and socio-environmental relevance, with significant losses occurring throughout the production chain, especially during the postharvest phase. The use of ozone arises as a promising and safe alternative to conventional chemical treatments to minimize these losses. This study aimed to evaluate the kinetic models of ozone reaction in water at different temperatures and to determine the effectiveness of immersion in ozonated water in controlling Colletotrichum musae in bananas, as well as to analyze the impacts on product quality during storage. For this, five treatments were tested on the 'Nanicão' banana variety: control (no immersion), immersion in water without ozone (two and three cycles), and immersion in ozonated water (two and three cycles). Each cycle lasted 15 minutes. After the treatment, the fruits were stored for 9 days at 25°C and 75% RH. The results showed that the highest ozone concentration and the longest half-life (117.6 minutes) were achieved at 15°C. However, in the presence of bananas, the half-life was drastically reduced to just 0.9 minutes. There was no significant effect of ozonated water treatment on anthracnose control or fruit quality during storage. It was concluded that, although the ozone half-life is longer at 15°C, the organic matter present in bananas substantially reduces this time, and immersion in ozonated water was not effective in controlling anthracnose. Keywords: musa spp; ozone; kinetic models; saturation; decay; post-harvest. | Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Water when subjected to magnetic fields undergoes physicochemical changes and when used in agriculture has shown interesting effects on plant development and seed germination. The objective was to evaluate the effects of magnetized water under germination and dormancy of lettuce seeds (Lactuca sativa) in view of the scarcity of available data on the subject. The experiment was conducted at the Federal University of Uberlandia campus Monte Carmelo, under laboratory conditions. Genotypes UFU-125#2#2#1, UFU-206#1#6#1 and the commercial cultivar Grand Rapids were used in a completely randomized experimental design DIC, being a factorial scheme 2x3. Comprising deionized water, magnetized water and temperatures of twenty-thirty degrees Celsius with four replications. The treatments and repetitions were conducted in gerbox with germitest paper, and each gerbox received twenty five seeds, totaling two hundred seeds of each genotype. Daily evaluations were performed for seven consecutive days according to the Rules for Seed Analysis – RAS for data collection. At the end, the results were processed using the SISVAR software and subjected to analysis of variance, the means were compared by Tukey test at the level of 5 % probability. The magnetized water did not provide significant gains in relation to deionized water for the germination of lettuce seeds, and the treatments with deionized and magnetized water received the same averages when subjected to the test. For the treatments submitted to temperature of 30 °C there was no seed twinning in both cases. | Trabalho de Conclusão de Curso (Graduação) | A água quando submetida a campos magnéticos sofre alterações físico-químicas e quando utilizadas na agricultura tem demonstrado efeitos interessantes no desenvolvimento de plantas e na germinação de sementes. O objetivo foi avaliar os efeitos da água magnetizada sob a germinação e dormência de sementes de alface (Lactuca sativa) tendo em vista a escassez de dados disponíveis sobre o assunto. O experimento foi conduzido na Universidade Federal de Uberlândia campus Monte Carmelo, em condições de laboratório. Foram utilizados genótipos UFU-125#2#2#1, UFU-206#1#6#1 e a cultivar comercial Grand Rapids, em um delineamento experimental totalmente casualizado DIC, sendo um esquema fatorial 2x3. Compreendendo água deionizada, água magnetizada e temperaturas de vinte e trinta graus célsius com quatro repetições. Os tratamentos e repetições foram conduzidos em gerbox com papel germitest, sendo que cada gerbox recebeu vinte cinco sementes, totalizando duzentas sementes de cada genótipo. Foram realizadas avaliações diárias durante sete dias consecutivos de acordo com as Regras para Análise de Sementes – RAS para a coleta dos dados. Ao final, os resultados foram processados utilizando o software SISVAR e submetidos à análise de variância, as médias foram comparadas pelo teste de Tukey ao nível de 5 % de probabilidade. A água magnetizada não proporcionou ganhos significativos em relação a água deionizada para a germinação das sementes de alface, tendo os tratamentos com água deionizada e magnetizada recebido as mesmas médias quando submetidas ao teste. Para os tratamentos submetidos a temperatura de 30 °C não houve geminação de sementes em ambos os casos.

Determinación de sodio en agua por fotometría de llama | Melián, Cecilia. Centro Universitario de Estudios Medioambientales. Cátedra de Química Biológica. Facultad de Ciencias Médicas de la UNR; Argentina

The objective of this research is to analyze the literature on rural water access and supply in Mexico and Brazil, considering existing systems; to propose improvement recommendations in these areas. Different methodologies were used to review the literature, such as searching various scientific databases, the use of the SCIMAGO ranking, the adoption of the Newcastle Ottawa scale, the PRISMA guidelines, and the STROBE verification. The time periods spanned key remote eras ending today. The results highlight that Latin American nations such as Brazil and Mexico have water systems that need greater commitment from the public sector. It is recommended to involve the social sector in the development of community management schemes to find a solution to the changing water demand and supply. In addition, it is necessary to delve in future research into the issue of water supply, for its improvement in the nations analyzed. | El objetivo de esta investigación es analizar la literatura sobre el acceso y suministro de agua rural en México y Brasil considerando los sistemas existentes para proponer recomendaciones de mejora en estos rubros. Se utilizaron diferentes metodologías para la revisión de la literatura, como la búsqueda en diversas bases de datos científicas, el empleo del ranking SCIMAGO, la adopción de la escala Newcastle Ottawa, las pautas de PRISMA y la verificación STROBE. Los periodos de tiempo abarcaron épocas remotas clave que finalizan en la actualidad: 1994-2020. Los resultados destacan que naciones latinoamericanas como Brasil y México tienen sistemas de agua que necesitan un mayor compromiso para mejorar por parte del sector público. Se recomienda hacer partícipe al sector social en el desarrollo de esquemas de gestión comunitaria para encontrar una solución a la demanda y oferta de agua cambiantes. Además, es menester en próximas investigaciones profundizar en el tema del abastecimiento del agua para su mejora en las naciones analizadas.

The aim of this study was to assess the quality of drinking water used for poultry on farms owned by producers from the free market in San Roque (Corrientes, Argentina). Water samples from wells were analyzed in situ for temperature, pH, and conductivity parameters. Laboratory analyses were performed for Calcium, Magnesium, Sodium, Potassium, Chlorides, Sulfates, and Nitrates. To assess microbiological quality, coliform bacteria and total mesophilic aerobes were determined. From a physicochemical perspective, 100% of the sampled farms had water sources of intermediate quality, which is considered acceptable for poultry drinking. The only parameter that could pose issues is pH, as only one establishment had water of intermediate quality for this variable, while the rest were not deemed suitable. In the studied area, the levels of total bacteria varied between establishments, and it was found that 100% of the farms had contamination levels exceeding acceptable limits. The results indicate that the use of these waters is not recommended for drinking by poultry in the farms of the free market producers in San Roque locality, as they are not bacteriologically suitable for consumption. From a physicochemical standpoint, only the pH parameter did not meet the standards in 95% of the evaluated farms. | El objetivo de este estudio fue determinar la calidad de las aguas utilizadas para la bebida de aves de consumo interno o familiar en granjas de productores de la feria franca de la localidad de San Roque (Corrientes, Argentina). Se utilizaron muestras de agua de perforaciones determinándose in situ: temperatura, pH, conductividad, mientras que en el laboratorio se realizaron determinaciones de Calcio, Magnesio, Sodio, Potasio, Cloruros, Sulfatos y Nitratos. Y para analizar la calidad microbiológica se determinaron bacterias coliformes y aerobios mesófilos totales. Desde el punto de vista físico químico el 100% de las granjas muestreadas presentaron fuentes de agua de calidad intermedia y recomendable para ser usadas como aguas de bebida para las aves. Sin embargo, el pH fue el único parámetro que podría causar inconvenientes ya que sólo un establecimiento tuvo aguas de calidad intermedia en esta variable y el resto presentaron valores no recomendables. En la zona estudiada, los niveles de bacterias totales variaron entre los establecimientos, y se encontró que en el 100% de las granjas los niveles de contaminación superaban los límites tolerables. Los resultados obtenidos nos permiten concluir que el uso de estas aguas no es recomendable para la bebida de aves de consumo interno o familiar en granjas de productores de la feria franca de la Localidad de San Roque debido a que desde el punto de vista bacteriológico no son aptas para el consumo. Desde el punto de vista físico químico, sólo el pH es el parámetro que no se ajusta a los estándares en un 95% de las granjas evaluadas.