On predicting the presence of birds in Eucalyptus forest types

We examine the relationship between the number of bird species and environment within 500 000 ha of eucalypt forests in south-eastern New South Wales, Australia. Birds were surveyed at 39 sites within 31 eucalypt communities, which were, in turn, scored by altitude, temperature, rainfall, basal areas of trees and levels of the nutrients nitrogen, phosphorus, potassium and magnesium in the eucalypt foliage.

Ninety bird species were recorded. Numbers per site, averaged over the whole sample period, ranged between 20 and 38 over all surveys, 24 and 42 in ‘summer’ (October to March) when migrant species were present, and 13 and 38 in ‘winter’ (April to September). A forward stepwise Poisson regression model was used to fit bird species richness to the environmental variables. Over all surveys and in ‘summer’, foliar magnesium and tree basal area (including the basal area of dead trees) were significantly (positive) correlated with the number of bird species. In ‘winter’ the correlations were with altitude and temperature (both negative), presumably the result of emigration of species that avoid cold weather, and tree basal area (positive).

The positive association of number of species over all surveys and in ‘summer’ with tree basal area, including dead trees, and foliar magnesium may index the level of forest maturity and productivity.

Forest management directed solely to timber production reduces the basal area and the number of dead trees and may thereby reduce bird species richness permanently.

A methodology is offered, based on the relationship between the physical environment and the more productive eucalypt communities, for determining forest areas containing the most species of birds.     

Application of a numerical algorithm to the selection of reserves in semi-arid New South Wales

An iterative analysis was used to identify the number and area of pastoral properties needed to contain the full range of natural environments (land systems) in part of western New South Wales. A minimum of 32 properties (3·1% of total number) and 7980 km² (5·7% of total area) was required to represent every land system at least once. Full representation required a greater overall number and area when the analysis began with properties already acquired for conservation. Excluding land systems atypical of the study area did not greatly reduce the number and area of properties required. Complete representation of land systems in each geographical subdivision in which they occur required a much greater overall number and area of properties than when the analysis was run for the study area as a whole. The algorithm used in this study produced very similar results to other iterative analyses applied to reserve selection in Australia.     

Effects of cement production on the elemental composition of soils in the neighborhood of two cement factories

The effects of cement production on the elemental composition of soils in the neighborhood of two cement factories in Nigeria have been investigated using the XRF and PIXE/RBS techniques. The concentration of 21 elements viz:-Mg, Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Pb, As, Zr, Rb and Br, were determined in about 30 samples. Calcium, P, S, Cr, Ni, Cu and Zn, were found to be relatively enriched in the soils of the cement factory premises. Calcium, a cement marker element, was found to be well correlated with Mg, S, Fe, Ni and Cu in the soils, and inversely proportional to the Si and Ti concentrations. From Ca/Si ratios and enrichment factors of the marker elements, it was found that soil contamination due to cement drops sharply with distance from the factories, and with increasing depth from the surface.     

Aqueous extracts from some muscles inhibit hemoglobin-mediated oxidation of cod muscle membrane lipids

It was evaluated whether trout hemoglobin (Hb)-mediated oxidation of minced washed cod muscle lipids could be prevented by an aqueous isolate from cod and some other muscle sources. Lipid hydroperoxides and painty odor developed approximately 4 days faster in washed than unwashed cod mince. When adding back an aqueous fraction (press juice) isolated from unwashed mince to washed mince at 2-6-fold dilutions, development of hydroperoxides and painty odor was either delayed or completely prevented. The inhibitory substances were heat stable, and their effect was slightly reduced at reduced pH. The <1 kDa fractions of whole and heated press juices were as inhibitory as the unfractionated press juices. Inhibition by the unheated, heated, and ultrafiltered (30 kDa) press juices was lost after dialysis. These findings implied the presence of one or more highly effective aqueous low molecular weight antioxidants in cod muscle press juice. The same antioxidative properties were found in heated haddock, dab, and winter flounder muscle press juices but not in heated herring and chicken muscle press juices. Unheated chicken press juice was however highly inhibitory.     

Positional effect on protein and oil content and composition of soybeans

Soybean (Glycine max [L.] Merr.) protein and oil qualities, with respect to monogastric nutrition, have been linked to the relative abundance of specific protein subunits and fatty acids, respectively. An analysis of field-grown soybean seeds by near-infrared spectroscopy revealed significant differences in their protein and oil contents as a function of nodal position. Seed proteins from the plant apex were high in protein and low in oil content, while those from the basal region exhibited an opposite pattern of accumulation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total seed proteins revealed that the beta-subunit of beta-conglycinin content was 4-fold higher in seeds from the apical nodes than in seeds from basal nodes. The glycinin A3 polypeptide content gradually increased in successively lower nodes from the top of the plant. Its accumulation was drastically reduced when nitrogen was applied at specific growth stages. Exogenous nitrogen did not alter the pattern of beta-subunit accumulation, but accrual of the acidic and basic polypeptides of glycinin was diminished. The remaining seed storage protein components were not influenced by nodal position or nitrogen application. Gas chromatographic analysis of fatty acids indicated that only oleic (18:0) and linoleic (18:2) acids showed variability in accumulation at different nodes. Neither the abundance nor the distribution of the fatty acids was altered by nitrogen application.     

Soil crusting and infiltration on steep slopes in northern Thailand

Predicting the rate at which rain infiltrates on steep slopes is very uncertain. There is no consistent information in the literature. We have therefore related infiltrability to slope gradient under field conditions by experimenting on a gravelly loamy soil occupying the upper half of a cultivated convex hill in northern Thailand. Fifteen 1 m × 1 m plots with slope gradients ranging from 16 to 63% were established, and simulated rain was allowed to fall on them at controlled rates and for fixed times. We obtained the following results. The surface fell 0.4–7.2 mm due to compaction and soil loss. The proportions of crust (0–40%) and embedded gravel (10–60%), the runoff coefficient (0.05–0.78 mm mm^?1), the mean sediment concentrations (0–5.6 g l^?1), and soil detachment (10–313 g m^?2) were more pronounced on the gentle slopes than on the steep ones. The steady final infiltration rate (1–107 mm hour^?1) increased sharply with increasing slope gradient. Microaggregates tended to behave like sand and become tightly packed on gentle slopes (packing crust). These results suggest that the vertical component of kinetic energy, which is greater on gentle slopes, has a dominant role. Nevertheless, the differences in compaction and in sediment concentration could not be ascribed to the vertical component of kinetic energy alone. On steep slopes the horizontal component of the kinetic energy is transformed into shear stress, hampering the development of crusts so that water can still infiltrate. On steeper slopes, the water film was thinner, thereby limiting the role of splash. We conclude that the relationship between slope gradient and infiltrability depends on the nature of the soil and must be examined in the light of surface crusting processes.     

Effect of harvesting and drying conditions on chlorophyll levels of soybean (Glycine max L. Merr)

Chlorophyll in soybean represents a downgrading factor for the crops. Five Brazilian cultivars were harvested between R(6) and R(8) stage of development (Fehr & Caviness scale) and dried at 25 degrees and 40 degrees C. The effect of maturity stages and two drying conditions after harvest were studied to achieve reduction of moisture and chlorophylls to acceptable levels. When seeds were dried at 25 degrees C, even harvesting at early stages of development such as R(6), the green pigments were almost degraded, and 16 ppm of chlorophyll were found at maximum, accompanied by loss of moisture. Moisture and chlorophyll declines as seed matures, but at intermediary stages (R(6)-R(7)), chlorophyll degrades first, so the rate of moisture loss should not be used to predict chlorophyll contents. At 40 degrees C, complete degradation of chlorophyll pigments is only achieved when seeds are swathed from R(7) stage up, otherwise the seed quality could be compromised. Slow drying allows almost complete removal of green pigments, even when seeds are swathed a few days before the physiological maturity stage.     

Enzyme-mediated solvent extraction of carotenoids from marigold flower (Tagetes erecta)

Marigold flowers are the most important source of carotenoids for application in the food industry. However, the extraction gives almost 50% losses of the carotenoids depending on conditions for silaging, drying, and solvent extraction. In the past decades, macerating enzymes have been successfully applied to improve the extraction yield of valued compounds from natural products. In this work, an alternative extraction process for carotenoids is proposed, consisting of a simultaneous enzymatic treatment and solvent extraction. The proposed process employs milled fresh flowers directly as raw material, eliminating the inefficient silage and drying operations as well as the generation of hard to deal with aqueous effluents present in traditional processes. The process developed was tested at the 80 L scale, where under optimal conditions a carotenoid recovery yield of 97% was obtained.     

防病促生枯萎病拮抗菌“98-Ⅰ”对4种枯萎病防治效果研究

经 8年系统试验研究从 330个细菌菌株中筛选出 1株防病促生枯萎病拮抗菌“98 Ⅰ” ,经鉴定属蜡质芽孢杆菌。该菌对黄瓜枯萎病、西瓜枯萎病、青椒枯萎病和番茄枯萎病 4种土传病害均有显著防治效果 ,其平皿孢子萌发抑制率分别为 79 2 %、75 1%、72 3%和 95 7% ,且该菌对多种蔬菜有促生和促进种子发芽功效。     

Model system for testing the efficacy of antioxidants in muscle foods

The objective of this research was to study the effect of the antioxidants, delta-tocopherol, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroquinone (TBHQ), and propyl gallate in a model system of lean muscle and canola oil and to compare the effects with those in minced herring. Two carrier solvents with different dielectric constants (epsilon), ethanol (epsilon = 24) and oil (epsilon= 2), were used. Oxidation was measured using thiobarbituric acid reactive substances (TBARS) and sensory analysis. In both the lean muscle-canola oil model system and in herring muscle, the hydrophilic antioxidants, propyl gallate and TBHQ, were more effective in providing oxidative stability than the lipophilic antioxidants, delta-tocopherol and BHT. The oxidative stability of a cod muscle-canola oil system in the presence of propyl gallate, and delta-tocopherol was not affected by the dielectric constant of the carrier solvent, while BHA was more effective as an antioxidant when added in the polar solvent ethanol.