20 research outputs found
Charge self-consistent dynamical mean-field theory based on the full-potential linear muffin-tin orbital method: methodology and applications
Full charge self-consistence (CSC) over the electron density has been
implemented into the local density approximation plus dynamical mean-field
theory (LDA+DMFT) scheme based on a full-potential linear muffin-tin orbital
method (FP-LMTO). Computational details on the construction of the electron
density from the density matrix are provided. The method is tested on the
prototypical charge-transfer insulator NiO using a simple static Hartree-Fock
approximation as impurity solver. The spectral and ground state properties of
bcc Fe are then addressed, by means of the spin-polarized T-matrix fluctuation
exchange solver (SPTF). Finally the permanent magnet SmCo is studied using
multiple impurity solvers, SPTF and Hubbard I, as the strength of the local
Coulomb interaction on the Sm and Co sites are drastically different. The
developed CSC-DMFT method is shown to in general improve on materials
properties like magnetic moments, electronic structure and the materials
density.Comment: 10 pages, 5 figure
Sources of mycosporine-like amino acids in planktonic Chlorella-bearing ciliates (Ciliophora)
Mycosporine-like amino acids (MAAs) are a family of secondary metabolites known to protect organisms exposed to solar UV radiation. We tested their distribution among several planktonic ciliates bearing Chlorella isolated from an oligo-mesotrophic lake in Tyrol, Austria. In order to test the origin of these compounds, the MAAs were assessed by high performance liquid chromatography in both the ciliates and their symbiotic algae.Considering all Chlorella-bearing ciliates, we found: (i) seven different MAAs (mycosporine-glycine, palythine, asterina-330, shinorine, porphyra-334, usujirene, palythene); (ii) one to several MAAs per species and (iii) qualitative and quantitative seasonal changes in the MAAs (e.g. in Pelagodileptus trachelioides). In all species tested, concentrations of MAAs were always <1% of ciliate dry weight.Several MAAs were also identified in the Chlorella isolated from the ciliates, thus providing initial evidence for their symbiotic origin. In Uroleptus sp., however, we found evidence for a dietary source of MAAs.Our results suggest that accumulation of MAAs in Chlorella-bearing ciliates represents an additional benefit of this symbiosis and an adaptation for survival in sunlit, UV-exposed waters
Respiratory Rate and Assessment of Secondary Production in the Holothuroid Holothuria tubulosa (Echinodermata) from Mediterranean Seagrass Beds
Respiration in Holothuria tubulosa was investigated in individuals from the Posidonia oceanica meadow off Lacco Ameno (Ischia Island, Italy). Respiratory rates increase with increasing body weight and increasing sea water temperature. Oxygen consumption of an average individual (7g dw body wall) ranges from 0.409 (14 °C) to 1.300 (26 °C) mg O2· h-1. Data on population density, mean size of individuals, and annual sea water temperature variations allow an assessment of holothuroid production. Values of 45.65 and 13.75 kJ · m-2· y-1 were calculated for shallow (3 to 10 m) and deep (25 to 33 m) areas of the Posidonia meadow, respectively. Holothuroid production shows a bathymetric pattern similar to primary production of the Posidonia-epiphytes complex and the production of Posidonia litter.SCOPUS: NotDefined.jFLWNAinfo:eu-repo/semantics/publishe