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 were determined by monitorin...

Complexity in ecological systems has challenged forest simulation modelers for years, resulting in a number of approaches with varying degrees of success. Arguments in favor of hierarchical modeling are made, especially for considering a complex environmental issue like widespread eastern hemlock regeneration failure. We present the philosophy and basic framework for the NORTHern Woodland Dynam...

The dynamics of root and hypocotyl colonization, and the gene expression patterns of several fungal virulence factors and plant defense factors have been analyzed and compared in the interaction of two Fusarium oxysporum f. sp. phaseoli strains displaying clear differences in virulence, with a susceptible common bean cultivar. The growth of the two strains on the root surface and the colonizati...

Competition for shared resources has long been viewed as an important structuring agent in natural communities (Gause 1934; Strong 1980). Generally defined as the simultaneous use of limited resources by two or more organisms, competition can negatively impact population growth rates and influence community-level processes such as predation and/or how species respond to disturbances (Roughgarde...

The development of blood cells has long served as a model system to study the generation of diverse mature cells from multipotent progenitors. The article by Org et al (2015) reveals how transcription factor competition on primed DNA templates may contribute to embryonic blood cell specification during the early stages of mesoderm development. The study not only provides new insights into the f...

spatial pattern of trees can possibly indicate stand history, population dynamics, and species competition. this research was investigated in the chahartagh forest reserve, ardal region, chaharmehal and bakhtiari province, central zagros forest, and southwest iranian state. in this study 53 hectare of the study area was selected and perfect inventory.  information includes the position and kind...

We show how, in general equilibrium models featuring increasing returns, imperfect competition and endogenous markups, changes in the scale of economic activity affect income distribution across factors. Whenever Þnal goods are gross-substitutes (grosscomplements), a scale expansion raises (lowers) the relative reward of the scarce factor or the factor used intensively in the sector characteriz...