The complexation reactions between Tl+ and Pb2+ ions and crown ethers 12-crown-4(12C4), 15-crown-5 (15C5), benzo-15-crown-5 (B15C5), 18-crown-6 (18C6), dicyclohexyl-18-crown-6 (DC18C6) and aza-18-crown-6 (A18C6) were studied in 90% acetonitrile and 90% ethanol solutions at 25 °C, using an a.c. polarographic technique. The stoichiometry and stability of the complexes we...

Crown class, an ordinal tree-level mensuration attribute used extensively by foresters, is di#icult to ass ign in thefield because def ini t ions of individual classes are confounded by ambiguous references to the position the tree in the canopy and amount of light received by its crown. When crown class is decomposed into its two elements-crown position and crown light exposure--field assignme...

Crown roots are the main components of the fibrous root system in rice (Oryza sativa). WOX11, a WUSCHEL-related homeobox gene specifically expressed in the emerging crown root meristem, is a key regulator in crown root development. However, the nature of WOX11 function in crown root development has remained elusive. Here, we identified a rice AP2/ERF protein, ERF3, which interacts with WOX11 an...

This study demonstrates the spectral data for two triarylmethane dyes, malachite green (MG) and crystal violet (CV) at room temperature. Effects of micellar environment, and crown ether addition on the spectral behaviour of the dyes were studied using absorption spectroscopic method. The dye-anionic surfactant interactions in micellar media were investigated. The chosen surfactants with differe...

Individual crown condition of Eucalyptus gomphocephala was assessed using two classification models to understand changes in forest health through space and time. Using high resolution (0.5 m) digital multispectral imagery, predictor variables were derived from textural and spectral variance of all pixels inside the crown area. The results estimate crown condition as a surrogate for tree health...

In the title compound, [Na(2)(N(3))(2)(C(21)H(34)N(2)O(6))(2)]·2CHCl(3), the sodium cation is hepta-coordinated by five O atoms of the crown ether unit of the 1-hexyl-3-(2,3,5,6,8,9,11,12-octa-hydro-1,4,7,10,13-benzopenta-oxacyclo-penta-decin-15-yl)urea (L) ligand, the O atom of the urea group of the second, symmetry-related L ligand, and one N atom of the azide anion. The experimentally determ...

ECOSYSTEMS CAN BE MODELED AT MANY different hierarchical levels. The phenomenon being simulated has a context represented by the next higher level of ecosystem organization, as well as driving mechanisms represented by the next lower level of ecosystem organization. In this sense, the level at which mechanisms are represented in models of tree crowns depends on the crown attributes or processes...