In situ evidence for renitrification in the Arctic lower stratosphere during the polar aura validation experiment (PAVE)

In-situ measurements of nitric acid (HNO3), ozone (O3), and nitrous oxide (N2O) were made from the NASA DC-8 during the Polar Aura Validation Experiment in January/February 2005. In the lower stratosphere (9–12.5 km, potential temperature 300–350 K) characteristic compact relationships were observed between all three gases. The ratio HNO3/O3 averaged 3.5 (±0.7) ppt/ppb. Samples with enhanced HNO3/O3 (\u3e4.0) were most abundant under the edge of the Arctic Polar vortex in airmasses with enhanced mixing ratios of both gases (\u3e400 ppb O3 and \u3e2000 ppt HNO3) and reduced mixing ratios of N2O (\u3c305 ppb), indicating air from higher levels in the stratosphere. Relationships to N2O in the anomalous samples under the vortex edge indicate that increases in HNO3/O3 reflect renitrification at DC-8 flight levels, with no indication of significant O3 loss. Renitrified air was only observed at potential temperatures above 340 K, and was most abundant on the PAVE flights on 27 and 29 January

A crystal base for the genetic code

The quantum enveloping algebra U_q(sl(2) \oplus sl(2)) in the limit q \to 0 is proposed as a symmetry algebra for the genetic code. In this approach the triplets of nucleotids or codons in the DNA chain are classified in crystal bases, tensor product of U_{q \to 0}(sl(2) \oplus sl(2)) representations. Such a construction might be compared to the baryon classification from quark building blocks in elementary particles physics, one of the main differences standing in the property of a crystal base to provide a natural order in the state constituents, this order being crucial in the codon. Then an operator ensuring the correspondence codon/amino-acid can be constructed out of the above algebra. It will be called the reading operator, and be such that two codons relative to the same (resp. different) amino-acid(s) acquire the same (resp. different) eigenvalue(s).Comment: LaTeX-2e document, package amsfonts, 11 page