Among outpatients with MDD, melancholic features were less likely in Hispanic patients, but more likely in slightly younger patients and in men. Melancholic features were also related to a slightly shorter current episode. These findings are consistent with the notion that external socio-demographic factors do not play an important role in the pathophysiology of melancholic depression.

The water hyacinth (Eichhornia crassipes) has drawn attention as a plant capable of removing pollutants, including toxic metals, from water. We are interested in the capacity of the water hyacinth to remediate aquatic environments that have been contaminated with the lanthanide metal, europium (Eu(III)). Using scanning electron microscopy (SEM) we have been able to determine that Eu(III) is adsorbed onto the surface of the roots from water and that the highest concentration of Eu(III) is on the root hairs. X-ray absorption spectroscopy (XAS) techniques were used to speciate the Eu(III) adsorbed onto the surface of the roots. The XAS data for Eu-contaminated water hyacinth roots provides evidence of a Eu-oxygen environment and establishes that Eu(III) is coordinated to 10-11 oxygen atoms at a distance of 2.44 Å. This likely involves binding of Eu(III) to the root via carboxylate groups and hydration of Eu(III) at the root surface.

Research on student argumentation in chemistry laboratories has mainly focused on evaluating the quality of students’ arguments and analyzing the structure of such arguments (i.e. claims, evidence, and rationale). Despite...