ALBERT

Notes: Abstract Community level interactions were studied in non-axenic sequencing batch reactors (SBRs) being used to treat 2,4-dinitrophenol (DNP). Increasing the influent DNP concentrations from 1 to 10 µg ml−1 eliminated large predatory organisms such as rotifers and ciliated protozoa from the SBRs. Under steady-state conditions at a DNP concentration of 10 µg ml−1, supplemental additions of glucose enhanced DNP degradation and led to the establishment of a microbial community consisting of five species of bacteria and a variety of microflagellates. The bacteria and flagellates exhibited oscillating population dynamics in this system, possibly indicating predator-prey interactions between these two groups. Only two of the five bacteria isolated from this system could utilize glucose as a growth substrate, and one of these two species was the only organism that could mineralize DNP in the system. The other three bacteria could grow using metabolic by-products of one of the glucose-utilizing strains (Bacillus cereus) found in the reactors. Supplemental glucose additions increased the average size of bacterial floc particles to 172 µm, compared with 41 µm in SBRs not receiving glucose. It is theorized that the enhanced mineralization of DNP in this non-axenic system was attributable to increased community interactions resulting in increased bacterial flocculation in SBRs receiving supplemental glucose additions.

Notes: Adsorption isotherms of mechanically mixed and freeze-dried mixtures of NaCl/casein at solute percentages of 1, 5, 10, 15, and 20 (wet basis) were obtained over the aw range 0.23–0.927 at 20°C. Experimental isotherm values were compared to those calculated by a mass balance equation. The mechanically mixed samples sorbed additively as predicted by the mass balance equation below 0.755 aw, whereas the freeze-dried mixtures sorbed more water than predicted (positive interaction) below 0.755 aw, Both types of mixtures sorbed less water than predicted by the mass balance equation (negative interaction) above the saturation aw of the NaCl, 0.755.

Notes: The effects of concentration, type and level of ingredients, heat and freeze/thaw treatments on the water mobility of starch-based fat re-placers were investigated. Water mobility in the starch-based fat re-placer samples containing gums, proteins or emulsifiers was similar to that of samples without additional ingredients. Water mobility was not affected by heat treatment, but was increased by freeze/thaw treatments. Water mobility in the solute containing samples was lower than in samples without additional ingredients and changed only slightly after heat and freeze/thaw treatments.

Notes: Interactions between sucrose and casein were investigated by adsorption isotherms. Mechanically mixed and freeze-dried sucrose/casein mixtures at sucrose percentages of 1, 5, 10, 15 and 20% (wet basis) were compared to calculated isotherms using the mass balance equation, over the aw range 0.23–0.93 at 20°C. The mechanical mixtures did not exhibit solute/polymer interactions. The freeze-dried systems showed positive interaction (i.e., sorbed more water than calculated) for 1 and 5% sucrose at all aw values. For the 10, 15 and 20% sucrose mixtures, positive interaction continued below 0.86 aw; however, above 0.86 aw, no interaction was apparent. That is, experimental sorption values equaled calculated values.

Notes: Reduced ascorbic acid (RAA) content, total chlorophyll and green color retention, enzyme activities and texture changes were followed in broccoli spears packaged in polymeric film and nonpackaged during 96 hr storage (10°C). Concentrations within packages monitored by gas chromatography were (CO2,) 8% and (02) 10%. RAA retention, moisture content, total chlorophyll and color retention were greater in packaged broccoli. No differences were found between packaged and nonpackaged broccoli for ascorbate oxidase and peroxidase activities, or texture.

Notes: Single-pulse multiplex coherent anti-Stokes Raman scattering (CARS) was used to obtain vibrational spectra of 20%/80% liquid nitrogen/argon mixtures, shock compressed to several high-pressure/high-temperature states. A semiclassical model for CARS spectra was used to extract best fit vibrational frequencies, peak Raman susceptibilities, and Raman linewidths from the data. Up to a maximum single shock pressure of 17.1 GPa, the N2 vibrational frequency was found to increase monotonically with pressure. The vibrational frequencies measured in both the singly and doubly shocked N2/Ar mixtures correspond within experimental error to those for pure nitrogen at equivalent pressures and temperatures, implying that the influence of the interaction potential on the N2 vibrational frequency for the N2/Ar collision is not significantly different from that of a N2/N2 collision at these conditions. The transition intensity and linewidth data suggest that thermal equilibrium of the vibrational levels is attained in less than 10 ns at these shock pressures. Vibrational temperatures obtained were used to improve the potential function of argon used to calculate equation-of-state pressures and temperatures. The measured linewidths suggest that the nitrogen vibrational dephasing time decreased to about 1 ps at the highest pressure shock state.

Notes: Magnetization behavior in antiferromagnetically (AFM) coupled multilayer systems was calculated by using an atomic layer model. Comparisons with the experimental results obtained on sputtered Co/Cu multilayers reveal remarkable differences in the magnetization reversal and in the field dependence of the magnetoresistance. Kerr loops measured from both sides of the stack display strong vertical differences. At the lower side near the Fe seed layer the magnetization reversal is in good agreement with that of our calculations whereas near the surface in large portions of the stack the AFM coupling is destroyed or varied. These effects are presumably caused by magnetic short circuits at defects in the multilayer structure. Cross-section transmission electron microscopy reveals growth defects which seem to be responsible for the deviations from the calculated ideal behavior.

Notes: Abstract The North Shore Volcanic Group in northern Minnesota is part of the Middle Proterozoic Keweenawan sequence, one of the largest plateau lava provinces in the world. The primary geochemistry of the basalts suggests that volcanism occurred in an intracontinental rift environment. The subaerial lava flows, mainly amygdaloidal olivine tholeiites and tholeiites, have undergone low-grade metamorphism from zeolite to lower greenschist facies. On the basis of alteration phases replacing the primary magmatic minerals, infilling amygdales and veins, and replacing secondary minerals, the following zones have been distinguished: (1) thomsonite-scolecite-smectite, (2) heulandite-stilbite-smectite, (3) laumontitechlorite-albite, (4) laumontite-chlorite-albite ± prehnite ± pumpellyite and (5) epidote-chlorite-albite ± actinolite zone.In addition to the overall zonation based on mineral parageneses, zonations in the composition of the Ab content of the newly formed albite replacing primary Ca-rich plagioclase and of the newly formed mafic phyllosilicates are observed within the sequence and within single flows. Mafic phyllosilicates in the upper part of the sequence (mainly smectites and mixed-layer smectite/chlorites) display high Si and Ca + Na + K contents, whereas in the lower part of the sequence the amounts of Si and Ca + Na + K are markedly lower (mainly chlorites and mixed-layer chlorite/smectites). Similar zonations are observed within the individual flows. The albite content of the newly formed plagioclase is highest, and the Si and Ca + Na + K content of the phyllosilicates lowest in the amygdaloidal flow top while the opposite is true for the massive flow interior.The above features suggest that the overall pattern is one of burial-type metamorphism associated with extension in the rift setting. In detail, the mineral assemblages are controlled not only by the stratigraphic position but also by the flow morphology controlling permeability whose effect on the assemblages is most pronounced in the stratigraphically upper parts. This suggests that at the first stages of alteration (lowest grade) the patterns of fluid flow were important effects in controlling the assemblages. At greater burial depth, assemblages are more homogeneous, perhaps representative of a more even and pervasive flow pattern.Using the observed assemblages at face value to define grade and/or facies, different conditions would be assigned within the different morphological flow portions. Thus at low-grade metamorphic conditions it is essential to integrate assemblages from different morphological flow portions in order to define satisfactorily the overall metamorphic conditions.