Quantifying the melt distribution and crustal structure across ridge-axis discontinuities is essential for understanding the relationship between magmatic, tectonic and petrologic segmentation of mid-ocean-ridge spreading centres. The geometry and continuity of magma bodies beneath features such as overlapping spreading centres can strongly influence the composition of erupted lavas and may give insight into the underlying pattern of mantle flow. Here we present three-dimensional images of seismic reflectivity beneath a mid-ocean ridge to investigate the nature of melt distribution across a ridge-axis discontinuity. Reflectivity slices through the 9 degrees 03' N overlapping spreading centre on East Pacific Rise suggest that it has a robust magma supply, with melt bodies underlying both limbs and ponding of melt beneath large areas of the overlap basin. The geometry of melt distribution beneath this offset is inconsistent with large-scale, crustal redistribution of melt away from centres of upwelling. The complex distribution of melt seems instead to be caused by a combination of vertical melt transport from the underlying mantle and subsequent focusing of melt beneath a magma freezing boundary in the mid-crust.

The kinetics of chlorophyll degradation and visual green color loss in pureed green peas with 80% moisture (w/w) were determined at 70, 80 and 90 C. The Ϫa value from a tristimulus colorimeter was chosen as the physical property and a technique based on fractional conversion was developed in the determination of kinetic parameters of visual green color loss. The degradation of chlorophyll a, chlorophyll b and greenness followed a first order reaction and the temperature dependence of these reactions indicated an Arrhenius relationship. The activation energies were 19.5, 17.1 and 18.2 kcal/mol, respectively.

Fractional conversion (ƒ) takes into account the nonzero texture property upon prolonged heating. This was applied as an alternate technique for reanalyzing texture degradation kinetics based on published data which indicated that the softening of vegetables followed a dual mechanism first order kinetic model. The plot of the logarithm of 1-ƒ vs heating time was linear through log cycles indicating the reaction was first order with a single rate constant and the substrate b was better characterized by the equilibrium (or maximum retainable) texture property. A possible explanation was developed for negative activation energies which had been reported for the second mechanism with some vegetables.

The determination of melt distribution in the crust and the nature of the crust-mantle boundary (the 'Moho') is fundamental to the understanding of crustal accretion processes at oceanic spreading centres. Upper-crustal magma chambers have been imaged beneath fast- and intermediate-spreading centres but it has been difficult to image structures beneath these magma sills. Using three-dimensional seismic reflection images, here we report the presence of Moho reflections beneath a crustal magma chamber at the 9 degrees 03' N overlapping spreading centre, East Pacific Rise. Our observations highlight the formation of the Moho at zero-aged crust. Over a distance of less than 7 km along the ridge crest, a rapid increase in two-way travel time of seismic waves between the magma chamber and Moho reflections is observed, which we suggest is due to a melt anomaly in the lower crust. The amplitude versus offset variation of reflections from the magma chamber shows a coincident region of higher melt fraction overlying this anomalous region, supporting the conclusion of additional melt at depth.

The degradation kinetics of (-)-epigallocatechin gallate (EGCG) as a function of pH (4 to 7) and dissolved oxygen concentration (0 to 7.59 mg/L) in citrate buffer solutions were determined. EGCG degradation followed a pseudofirst order kinetic model, regardless of the conditions when the fractional conversion technique was applied for data reductions. The rate constant increased log-linearly with respect to both pH and dissolved oxygen concentration. The temperature dependence of the rate constant was adequately modeled by the Arrhenius equation with an average activation energy of 18.7 ± 1 kcal/mol. A mathematical model that relates the rate constant to temperature, pH, and dissolved oxygen concentration was developed and validated. These results can help predict losses of EGCG during processing and/or storage.