New enzymes with potential for PET surface modification

This work describes newly isolated organisms and their potential to modify the surface of polyethylene terephthalate (PET). Out of the different screening processes, four bacterial and five fungal strains were isolated. A PET model substrate was synthesized (bis (benzoyloxyethyl) terephthalate) and used in the screening process, mimicking the polymer in its crucial properties and having the advantage of defined hydrolysis products. On this model substrate, extracellular enzyme preparations from the isolated microorganisms showed a maximum activity of 8.54 nkat/L. All enzyme preparations showed esterase activity on p-nitrophenyl-acetate while no activity was found on p-nitrophenyl decanoate or p-nitrophenyl palmitate. Increased hydrophilicity of PET fabrics after enzyme treatment was found based on rising height and water dissipation measurements

Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc

Borboletas (Lepidoptera: Hesperioidea e papilionoidea) de val de serra, região central do rio grande do sul, Brasil

The butterfly fauna of the Atlantic Forest Biome is reasonably well-known up to the southern limit of its distribution. However, there are knowledge gaps nearby the central region of Rio Grande do Sul State, whose forest areas are considered priorities for biological conservation. This study investigated the butterfly assemblage of a riparian fragment in an ecotone area between Mixed Ombrophilous Forest and Seasonal Decidous Forest, in Itaara municipality. From September 2005 to September 2006, after 105 net-hours through active search sampling, 877 butterflies were registered representing 104 species. Three more species were registered posteriorly, increasing total richness to 107. The most abundant species were the Nymphalidae Hermeuptychia hermes (Fabricius, 1775), Yphthimoides celmis (Godart, [1824]), Agraulis vanillae maculosa (Stichel, [1908]), Tegosa claudina (Eschscholtz, 1821) and Vanessa braziliensis (Moore, 1883). One new record for the State and four new ones for the central region were registered besides the southern endemic Papilionidae Euryades corethrus (Boisduval, 1836) and the Lycaenidae Arcas ducalis (Westwood, 1852), considered indicator of Atlantic forest preserved areas. Due to the representativeness of the registered fauna, it is suggested the increase of conservation efforts in the area and stimulation of new ecological studies with the local biodiversity