Prosopis laevigata es una especie con amplia distribución en zonas áridas del norte y centro de México; desde el punto de vista ambiental es muy útil pues previene los procesos de desertificación y erosión por su alta capacidad de retención del suelo, de mejoramiento de la fertilidad y de estabilizar la salinidad. Es fuente de alimento y refugio para la fauna silvestre y produce diversos bienes para el ser humano, por lo que ha sido sobreexplotada desde hace décadas en el país; por lo tanto, es ya necesario determinar zonas potenciales para su establecimiento. Para ello, se trabajó con la distribución potencial de esta especie en tres provincias fisiográficas. Se recabaron datos espaciales de avistamientos registrados en la Red Mundial de Información sobre Biodiversidad (REMIB) y se seleccionó el modelo de nicho ecológico BIOCLIM, que fue aplicado en el programa DIVA-GIS ver. 7.5. Se le validó con un análisis de área bajo la curva (ROC) y el estimador Kappa. Los resultados sugieren que P. laevigata puede crecer de manera óptima en 15 % de las provincias (70 632.08 km2) y los factores más limitantes que enfrenta son la estacionalidad de precipitación (9.25 %) y la temperatura (11.43 %). Los análisis ROC y Kappa indican que el modelo utilizado tiene un excelente desempeño y una alta probabilidad de acierto (ROC = 0.973; Kappa = 0.915), por lo que estas fórmulas son adecuadas para determinar áreas potenciales para el desarrollo de la especie.
Road tunnels have been a successful means of avoiding congestion in the city of Guanajuato.They are also used by pedestrians to reduce travel time and distance. However, exposure to elevated levels of carbon monoxide (CO) and particulate matter such as PM2.5 and PM10 from vehicle emissions, as well as the resuspension of particulate matter are risk factors for health. In the city of Guanajuato, the CO, PM2.5 and PM10 concentrations, wind speed and number of vehicles in three of the more polluted and most frequently used tunnels by pedestrians was monitored. To monitor the CO concentration, non-dispersive infrared radiation was used. The PM2.5 and PM10 concentrations were evaluated using a handheld analyzer with a high precision laser sensor (Aerocet-831). The mineralogy, chemical composition, and morphology of particulate matter were analyzed by XRD, XRF and SEM-EDS, respectively. The average CO concentration does not exceed 50 ppm for an exposure time of 30 minutes as recommended by the World Health Organization, however the average concentrations for PM10 in the three tunnels are above the permissible limit of 50 µg m -3 24-hour average for the air quality inside the tunnels. The high emission factors suggest the necessity of the implementation of a ventilation system inside the tunnels. The chemical composition of particulate matter corresponds to the mineral dust present.
This study employed the use of 16S rRNA gene sequence analysis to identify three of four native bacterial strains isolated from crude oil-contaminated site in Poza Rica, Veracruz, Mexico. The identified bacteria were Ochrobactrum intermedium, Pandoraea pnomenusa and Ochrobactrum sp., but SA2-09 strain was not identified. The ability of the isolates to degrade polycyclic aromatic hydrocarbons (PAHs) was evaluated at 31.61 and 54.52 mg/kg PAHs in soil, when used as crude oil in soil microcosm during 80 days of incubation at 30°C. The results demonstrated that O. intermedium biodegraded many PAHs, including the high molecular weight (HMW) PAHs fluoranthene (100% equivalent 0.24 mg/kg), benzo [b] fluoranthene (81.8% equal 0.18 mg/kg), Benzo[a]pyrene (87.0%, 0.20 mg/kg) and Benzo[g,h,i]perylene (52.7%, 0.39 mg/kg). P. pnomenusa had a degradation profile of HMW PAHs, which was similar to O. intermedium, while Ochrobactrum sp. and the strain SA-09 exhibited lower degradation rates of HMW.
En este documento se comenta el informe Captura de carbono en los suelos para un mejor manejo de la tierra[1] , en el que se analiza el potencial de los suelos agrícolas, forestales y de pastoreo para actuar como sumideros de carbono. Primero se revisa la dinámica actual de este elemento en los suelos y los factores que la regulan; posteriormente se proponen medidas de manejo para cada uso de suelo y finalmente se hace un análisis de las alternativas propuestas.
The historical contamination of soils by heavy metals shows little degradation and therefore they are considered as persistent bioaccumulative toxins, which represent a marked risk to human health ecosystems. In recent years, technologies have been developed to help alleviate the problem of contaminated soils. The methods developed have mainly focused on in situ remediation, among which electro remediation stands out for both organic and inorganic pollutants. The present work aims to analyze variables for the treatment of soils with heavy metals using electrochemical strategies with the application of commercial membranes. The analysis made it possible to determine the transition zone where the depletion of the counterion occurs in the diffusion layer of the cadmium and lead ion. The results of the limit current analysis in the membrane reflect the presence of a mixture of ions where the diffusion layer is altered by the mixture of ions present. The results suggest that the membrane presents fouling of complexing organic compounds in the diffusion layer and therefore behaves like a reactive membrane where the permeation channels and the fixed charge change their original function.
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