Symmetry Scheme for Amino Acid Codons

Group theoretical concepts are invoked in a specific model to explain how only twenty amino acids occur in nature out of a possible sixty four. The methods we use enable us to justify the occurrence of the recently discovered twenty first amino acid selenocysteine, and also enables us to predict the possible existence of two more, as yet undiscovered amino acids.Comment: 18 pages which include 4 figures & 3 table

Lie Superalgebras and the Multiplet Structure of the Genetic Code II: Branching Schemes

Continuing our attempt to explain the degeneracy of the genetic code using basic classical Lie superalgebras, we present the branching schemes for the typical codon representations (typical 64-dimensional irreducible representations) of basic classical Lie superalgebras and find three schemes that do reproduce the degeneracies of the standard code, based on the orthosymplectic algebra osp(5|2) and differing only in details of the symmetry breaking pattern during the last step.Comment: 34 pages, 9 tables, LaTe

Performance of peat biofilters treating ethyl acetate and toluene mixtures under non-steady-state conditions

[Abstract] This paper presents the response of peat biofilters to loading changes corresponding to industrial practices such as overnight and weekend shutdowns, intermittent emission or inlet concentration peaks. Three laboratory-scale reactors fed with air contaminated with ethyl acetate, toluene or a 1:1 mixture of ethyl acetate and toluene were operated under 65 g m-3 h-1 inlet load and 60 s EBRT during 16 h/day, 5 days/week. Dynamic behavior after feed resumption after night and weekend closures showed a 1-2 h period of transient response to recover stable CO2 production values. No increase in VOC emission was observed, except for biofilters treating toluene for which a transient peak in VOC emission during 4-8 h after weekend closures was detected. More stressful conditions such as intermittent emissions (2 h-on/ 2 h-off, 16 h/day, 5 days/week), or inlet concentration peaks (40-min, 50% increase) were successfully handled in the biofilter treating only ethyl acetate; but deterioration in the operation was observed in presence of toluene. The system performance after 15-days starvation period was fully recovered in less than 8 h of re-acclimation period. Living and dead cells monitoring results are also presented