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Notes: Infrared transmission spectra of silicon dioxide (SiO2) thin films (∼4500 A(ring)) prepared by plasma-enhanced chemical-vapor deposition have been quantitatively analyzed. The films were deposited at different substrate temperatures (30–450 °C) using tetraethoxysilane (TEOS)/He, TEOS/He/O2, and TEOS/O2 gas mixtures in a parallel-plate radio-frequency reactor. The infrared transmission fits prove to be very accurate showing evidence of deconvolution into three separated Gaussian profiles to account for the asymmetric line-shape feature of the infrared stretching peak between 950 and 1300 cm−1. The examination of the Fourier transform infrared spectroscopy spectra in the complete frequency range (400–4000 cm−1) and ex situ x-ray photoelectron spectroscopy spectra indicates that some extra structures originate from the incorporation of carbon and hydrogen impurities in the film. As the substrate deposition temperature is increased, impurities are gradually removed from the growing layer. Films deposited at high substrate temperatures reveal a better stoichiometry and present similar deconvolution bands regardless of the gas-phase composition; the corresponding frequencies are shifted to lower energies compared to thermal oxides. In addition, the intensity of the first Gaussian profile, associated with the low-energy asymmetry of the stretching peak, increases with the substrate deposition temperature while the intensity of the third Gaussian profile associated with the presence of the high-energy peak shoulder decreases. The vibrational properties of the film seem to be strongly related to the deposition conditions.

Notes: The phase shift between the pattern of light onto a photorefractive crystal and the resulting hologram at the very beginning of the recording process in two-wave mixing is analyzed and measured as a function of the applied electric field. These data allow one to compute the diffusion length of photoexcited charge carriers and to evaluate the actual electric field inside the crystal. A diffusion length of 0.14 μm is measured in a nominally undoped photorefractive Bi12TiO20 crystal using a 532 nm wavelength laser illumination, in agreement with results obtained from other methods. © 1997 American Institute of Physics.

Notes: The effects of NaCl and CaCl2 on the texture of olives, both treated and untreated with NaOH, at pH values lower than 4.0 were determined. Firmness of green olives declined as the pH decreased when calcium ions were not added. Calcium ions inhibited the softening rate of fresh and Spanish style green olives although this inhibitory effect depended on the pH. This firming action of calcium was higher at lower pH for fresh olives and at higher pH values for Spanish style green olives. The inhibitory effect of calcium on softening rate diminished as the concentration of cation increased. The presence of NaCl did not have any effect on the texture of either type of green olives. Lactic acid increased the softening rate of green olives by a higher proportion than acetic acid.

Notes: Sequence information was obtained on the variation of the ELA-DRB upstream regulatory region (URR) after polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) cloning and sequencing of ≈ 220 bp upstream of the first exon of horse DRB genes. The sequence of the proximal URR of equine DRB is composed of highly conserved sequence motifs, showing the presence of the W, X, Y, CAAT and TATA conserved boxes of major histocompatibility complex (MHC) class II promoters. Five different polymorphic horse DRB promoter sequences were detected in five horse breeds. The results demonstrate the existence of polymorphism in the nucleotide sequences of the ELA-DRB URR, located in the functionally important conserved consensus sequences, the X2 box, the Y box and the TATA box, while conservation were observed in X1 and CAAT boxes. The nucleotide diversity among horse URRs was intermediate between that seen within human and mouse DRB promoters, suggesting the existence of another important source of variability in ELA-DRB genes. In addition, phylogenetic comparisons, identity analysis and sequence organization suggested that the reported sequences would correspond to an expressed ELA-DRB locus. However, further information about the functional significance of these promoter polymorphisms will probably be acquired through expression studies on the different sequences.

Notes: Storage of ripe olives in liquids with high acetic acid content under anaerobic conditions led to glucose accumulation, low ethanol, and high chemical oxygen demand (COD). In contrast, low acid concentrations and anaerobic conditions produced a high level of ethanol and slightly lower COD while aerobic conditions produced low glucose, ethanol and COD. Surface color of ripe olives improved when storage liquids were used in the second washing of the darkening step. Firmness also increased with increasing proportion of storage liquids reuse, although olives from highly acidic media were softer than those stored in low acid media.

Notes: Fourteen isozymatk loci have been analyzed in 23 samples of populations belonging to genus Secale by starch gel electrophoresis. The allelic frequencies for these loci have also been estimated and used in calculating genetic identity values between populations. Isozymatic data agree with the hypothesis that there are four species in the genus Secale: S. cereale, S. montanum, S. silvestre, and S. vavilovii. The characteristics of growth and outbreeding habits, and the isozymatic variability along with the previously known cytogenetic data, maintain S. montanum as the probable ancestor of the other three species: two are self-pollinated and monomorphic for isozymes (S. silvestre and S. vavilovii) and the other is open-pollinated and variable (S. cereale) and dearly distinguishable by its genetic variability from the other two. Finally, from isozymatic data it is not possible to distinguish between populations belonging to S. montanum and populations, belonging to. S. cereale.

Notes: 1. Shallow lake ecosystems are normally dominated by submerged and emergent plants. Biological stabilising mechanisms help preserve this dominance. The systems may switch to dominance by phytoplankton, however, with loss of submerged plants. This process usually takes place against a background of increasing nutrient loadings but also requires additional switch mechanisms, which damage the plants or interfere with their stabilising mechanisms.2. The extent to which the details or even major features of this general model may change with geographical location are not clear. Manipulation of the fish community (biomanipulation) has often been used to clear the water of algae and restore the aquatic plants in northerly locations, but it is again not clear whether this is equally appropriate at lower latitudes.3. Eleven parallel experiments (collectively the International Mesocosm Experiment, IME) were carried out in six lakes in Finland, Sweden, England, the Netherlands and Spain in 1998 and 1999 to investigate the between-year and large-scale spatial variation in relationships between nutrient loading and zooplanktivorous fish on submerged plant and plankton communities in shallow lakes.4. Comparability of experiments in different locations was achieved to a high degree. Cross-laboratory comparisons of chemical analyses revealed some systematic differences between laboratories. These are unlikely to lead to major misinterpretations.5. Nutrient addition, overall, had its greatest effect on water chemistry then substantial effects on phytoplankton and zooplankton. Fish addition had its major effect on zooplankton and did not systematically change the water chemistry. There was no trend in the relative importance of fish effects with latitude, but nutrient addition affected more variables with decreasing latitude.6. The relative importance of top-down and bottom-up influences on the plankton differed in different locations and between years at the same location. The outcome of the experiments in different years was more predictable with decreasing latitude and this was attributed to more variable weather at higher latitudes that created more variable starting conditions for the experiments.

Notes: 1. Results are analysed from 11 experiments in which effects of fish addition and nutrient loading on shallow lakes were studied in mesocosms. The experiments, five in 1998, six in 1999, were carried out in six lakes, distributed from Finland to southern Spain, according to a standard protocol.2. Effects of the treatments on 29 standard chemical, phytoplankton and zooplankton variables are examined to assess the relative importance of bottom-up (nutrient enrichment) and top-down (fish predation) effects. For each year, the experiments in different locations are treated as replicates in a meta-analysis. Results of individual experiments are then compared in terms of the patterns of significant influences of nutrient addition and fish predation with these overall results (the baseline), and between years in the same location.3. The overall meta-analysis gave consistent results across the 2 years, with nutrient loading influencing all of the chemical variables, and on average 31% of primary producer and 39% of zooplankton variables. In contrast, fish influenced none of the chemical variables, 11% of the primary producer and 44% of the zooplankton variables. Nutrient effects on the system were thus about three times greater than fish effects, although fish effects were not inconsiderable.4. The relative importance of nutrients and fish in individual experiments often differed between years at the same location and effects deviated to varying degrees from the baseline. These deviations were treated as measures of consistency (predictability) of conclusions in repeat experiments. Consistency increased southwards and this is interpreted as a consequence of more variable annual weather northwards.5. The influence of nutrient loading was greater southwards and this was probably manifested through naturally greater annual macrophyte abundance in warmer locations in consequence of the longer plant growing-season. There was no trend in the relative importance of fish effects with latitude but this may partly be an artefact of the simple fish community used. These findings suggest that nutrient control should be a greater priority than biomanipulation in the restoration of eutrophicated shallow lakes in warm temperate regions.6. Starting conditions affected the outcome of experiments. High initial concentrations of total phosphorus and planktonic chlorophyll a concentration (created by local conditions prior to the experiment) led to de-emphasis of the importance of nutrient loading in the experiment.

Notes: 1. The impacts of nutrients (phosphorus and nitrogen) and planktivorous fish on phytoplankton composition and biomass were studied in six shallow, macrophyte-dominated lakes across Europe using mesocosm experiments.2. Phytoplankton biomass was more influenced by nutrients than by densities of planktivorous fish. Nutrient addition resulted in increased algal biomass at all locations. In some experiments, a decrease was noted at the highest nutrient loadings, corresponding to added concentrations of 1 mg L−1 P and 10 mg L−1 N.3. Chlorophyll a was a more precise parameter to quantify phytoplankton biomass than algal biovolume, with lower within-treatment variability.4. Higher densities of planktivorous fish shifted phytoplankton composition toward smaller algae (GALD 〈 50 μm). High nutrient loadings selected in favour of chlorophytes and cyanobacteria, while biovolumes of diatoms and dinophytes decreased. High temperatures also may increase the contribution of cyanobacteria to total phytoplankton biovolume in shallow lakes.