On pairwise Lindelöf spaces

In this paper we define pairwise Lindelöf spaces and study their properties and their relations with other topological spaces. We also study certain  conditions by which a bitopological space will reduce to a single topology. Several examples are discussed and many well known theorems are generalized concerning Lindelöf spaces.En este artículo se definen espacios p-Lindelöf y se estudian sus propiedades y relaciones con otros tipos de espacios topológicos. También se estudian ciertas condiciones bajo las cuales un espacio biotipológico (con dos topologías) se reduce a uno con una sola topología. Se discuten varios ejemplos y se generalizan varios teoremas sobre espacios de Lindelöf

Agricultural Mitigation Strategies to Reduce the Impact of Romaine Lettuce Contamination

Background: Leafy greens, particularly romaine lettuce, are often associated with outbreaks due to their susceptibility to contamination from various environmental sources. This study aimed to evaluate the presence of E. coli, Salmonella, copper, nickel, zinc, and manganese in irrigation water, lettuce leaves, and agricultural soil in the Litani River Basin (LRB), Lebanon. Method: Samples were collected from five demonstration plots employing different agricultural practices. Heavy metal concentrations were determined using atomic absorption spectrometry, while E. coli and Salmonella testing were conducted through conventional culturing techniques. The impact of E. coli contamination on seed germination and the interaction effects between E. coli and heavy metals were also examined. The study also compared the effectiveness of various irrigation systems in reducing bacterial contamination. Results: The results demonstrated that contamination levels varied significantly across the plots and irrigation types. This variation underscores the necessity of site-specific mitigation strategies to enhance food safety. Our findings highlight the importance of selecting appropriate irrigation methods and implementing tailored agricultural practices to minimize the risk of contamination. Conclusion: This research provides valuable insights for optimizing agricultural practices in the LRB to ensure food safety and environmental sustainability

Significant Correlation of Species Longevity with DNA Double Strand Break-Recognition but not with Telomere Length

The identification of the cellular mechanisms responsible for the wide differences in species lifespan remains one of the major unsolved problems of the biology of aging. We measured the capacity of nuclear protein to recognize DNA double strand breaks (DSB) and telomere length of skin fibroblasts derived from mammalian species that exhibit wide differences in longevity. Our results indicate DNA DSB recognition increases exponentially with longevity. Further, an analysis of the level of Ku80 protein in human, cow, and mouse suggests that Ku levels vary dramatically between species and these levels are strongly correlated with longevity. In contrast mean telomere length appears to decrease with increasing longevity of the species, although not significantly. These findings suggest that an enhanced ability to bind to DNA-ends may be important for longevity. A number of possible roles for increased levels of Ku and DNA-PKcs are discussed