Widespread sewage pollution of the Indian River Lagoon system, Florida (USA) resolved by spatial analyses of macroalgal biogeochemistry.

The Indian River Lagoon (IRL) system, a poorly flushed 240 km long estuary in east-central Florida (USA), previously received 200 MLD of point source municipal wastewater that was largely mitigated by the mid-1990's. Since then, non-point source loads, including septic tank effluent, have become more important. Seventy sites were sampled for bloom-forming macroalgae and analyzed for δN, % nitrogen, % phosphorus, carbon:nitrogen, carbon:phosphorus, and nitrogen:phosphorus ratios.

Atmospheric nitrogen deposition from a remote source enriches macroalgae in coral reef ecosystems near Green Turtle Cay, Abacos, Bahamas.

Over the past several decades, the fixation of "new" nitrogen to the biosphere has doubled. For the early 21st century, the most significant rate increases in atmospheric nitrogen deposition are predicted for developing nations. Wet nitrogen deposition was assessed on the remote island of Green Turtle Cay, Bahamas in a dry and wet season from January to July 2000.

[How I explore...significance of ophthalmoscopy in patients with arterial hypertension].

The ocular fundus is the only examination which allows a simple and non invasive visualisation of the terminal vascular system. Feature analysis of fundus examination supposes a similar vascular state in the other organs and permits direct diagnostic, prognostic and therapeutic choices. This article will emphasize the value of an ophthalmoscopy examination in patients with arterial hypertension.

Technique for incorporating the density functional Hessian into the geometry optimization of biomolecules, solvated molecules, and large floppy molecules.

Traditional geometry optimization methods require the gradient of the potential surface, together with a Hessian which is often approximated. Approximation of the Hessian causes difficulties for large, floppy molecules, increasing the number of steps required to reach the minimum. In this article, the costly evaluation of the exact Hessian is avoided by expanding the density functional to second order in both the nuclear and electronic variables, and then searching for the minimum of the quadratic functional.