(Table S1) Uranium and Thorium isotopes and U/Th ages of IODP Exp310 cores from offshore Tahiti

The timing of sea-level change provides important constraints on the mechanisms driving Earth's climate between glacial and interglacial states. Fossil corals constrain the timing of past sea level by their suitability for dating and their growth position close to sea level. The coral-derived age for the last deglaciation is consistent with climate change forced by Northern Hemisphere summer insolation (NHI), but the timing of the penultimate deglaciation is more controversial. We found, by means of uranium/thorium dating of fossil corals, that sea level during the penultimate deglaciation had risen to ~85 meters below the present sea level by 137,000 years ago, and that it fluctuated on a millennial time scale during deglaciation. This indicates that the penultimate deglaciation occurred earlier with respect to NHI than the last deglacial, beginning when NHI was at a minimum.

Water sorption into poly[(2-hydroxyethyl methacrylate)-co-(1-vinyl-2-pyrrolidone]at 310 K

Poly(2-hydroxyethyl methacrylate) and copolymers of 2-hydroxyethyl methacrylate (HEMA) and 1-vinyl-2-pyrrolidone (VP) in the form of cylindrical samples (approximate to8mm x 20mm) have been prepared and the sorption of water into these cylinders has been studied by the mass-uptake methods and by magnetic-resonance imaging. The equilibrium water contents for the cylinders were found to vary systematically with the copolymer composition. Diffusion of water into the cylinders was found to follow Fickian behaviour for cylinders with high HEMA contents, with the diffusion coefficients obtained from mass-uptake studies dependent on the copolymer composition, varying from 1.7 x 10(-11) m(2) s(-1) for poly(HEMA) to 2.0 x 10(-11) m(2) s(-1) for poly(HEMA-co-VP) with a composition of 1:1. However, NMR-imaging studies showed that, while the profiles of the water diffusion fronts for cylinders with high HEMA contents were Fickian, that for the 1:1 copolymer was not and indicated that the mechanism was Case III. The polymers which were rich in VP were characterized by a water-sorption process which follows Case-III behaviour. (C) 2003 Society of Chemical Industry.

Jornal da UNESP, 2015, ano XXX, n. 310

Jornal elaborado pela Assessoria de Comunicação e Imprensa da Reitoria da UNESP