Effects of Nutrients on Productivity and Morphology of Typha angustifolia x latifolia

The productivity of natural stands of cattails (Typha latifolia) has been correlated with the amounts of nutrients in the soil and water by Boyd and Hess (Ecology, 51: 296, 1970). The direct effects of varying levels of nitrogen (N), phosphorus (P) and potassium (K) on productivity were examined in our study by growing cattails in Hoagland\u27s nutrient solution. Concentrations of ¼, 1/16, and 1/64 the amount of N present in complete Hoagland\u27s solution (0.01Ml resulted in 63 percent, 48 percent and 26 percent of the dry weight of plants grown in complete solution. Rhizomes used to start plants contained considerable amounts of P and K since growth in solutions with no P or no K resulted in dry weights up to 37 percent of that of plants grown in complete solution. Nutrient availability also affected plant morphology . Reduced N increased root growth up to 75 percent greater than that of plants grown in complete solution

Geographic analysis of latent tuberculosis screening: A health system approach.

BackgroundNovel approaches are required to better focus latent tuberculosis infection (LTBI) efforts in low-prevalence regions. Geographic information systems, used within large health systems, may provide one such approach.MethodsA retrospective, cross-sectional design was used to integrate US Census and Duke Health System data between January 1, 2010 and October 31, 2017 and examine the relationships between LTBI screening and population tuberculosis risk (assessed using the surrogate measure of proportion of persons born in tuberculosis-endemic regions) by census tract.ResultsThe median proportion of Duke patients screened per census tract was 0.01 (range 0-0.1, interquartile range 0.01-0.03). The proportion of Duke patients screened within a census tract significantly but weakly correlated with the population risk. Furthermore, patients residing in census tracts with higher population tuberculosis risk were more likely to be screened with TST than with an IGRA (pConclusionThe weak correlation between patient proportion screened for LTBI and our surrogate marker of population tuberculosis risk suggests that LTBI screening efforts should be better targeted. This type of geography-based analysis may serve as an easily obtainable benchmark for LTBI screening in health systems with low tuberculosis prevalence