Complex marine trace fossils

Structurally elaborate burrow systems deserve special attention from ichnologists as the products of complex, variable behavior. Ichnogenera such as Zoophycos, Paleodictyon and Phymatoderma in some cases record deliberate restructuring of habitats, modulation of disturbances, and active control of food supplies. Thus they cannot be accommodated in the traditional ethologic classification of trace fossils.     

Human ecology and space age technology: Some predictions

Four predictions are made on the future of space age technologies in human and cultural ecology: first, remote sensing systems will generate a need for more fieldwork, not less; second, the services and skills of anthropologists will become essential to the interpretation of satellite data, especially as these relate to areas characterized by non-Western cultural practices; third, training in remote sensing and the use of geographic information systems will become a regular offering for anthropology students; and fourth, since these new systems and methods can be applied retrospectively to the re-analysis of earlier ethnographic works, space age technologies will be with us for some time to come.     

Divergence of mycorrhizal fungal communities in crop production systems

Mycorrhizal fungi are present in all arable soils and colonize nearly all crops and weed pests of crops. They may be involved as mutualists or pathogens of crops in well known but poorly understood phenomena such as crop rotation and green manure effects on soil productivity. Crop change effects on mycorrhizal fungal community parameters were evaluated in three field experiments. In Experiment 1, soybean (Glycine max (L.) Merr. cv. Douglas) was grown continuously or rotated with corn (Zea mays L.), milo (Sorghum bicolor (L.) Moench), or fescue (Festuca arundinacea Schreb cv. Johnstone) for two years, then soybean was grown on all plots. Continuous soybean plots were dominated byGigaspora spp., while rotated crops were dominated byGlomus spp. Differences in communities and community indices of continuous soybean and rotated plots were reduced after growing soybeans on rotated plots. In Experiment 2, a fescue sod was plowed and pearl millet (Pennisetum americanum Leeke) or crabgrass (Digitaria sanguinalis (L.) Scop.) grown. Both hosts resulted in great changes in populations of individual species, decreases in community dominance, and increases in community diversity and equitability. Crabgrass also resulted in reduced species richness. In Experiment 3, tobacco (Nicotiana tabacum L.) or fescue was planted on adjacent tracts of land with a long-term history of either fescue (30 yr) or sorghum-sudangrass (Sorghum bicolor (L.) Moench. ×S. sudanense (Piper) Staph.) (3 yr). The long-term cropping history had major effects on the mycorrhizal fungal communities which were related to the expression of mycorrhizal stunt disease of tobacco. Changes occurred in these communities in response to either current-season crop. These experiments suggest that crop rotation causes large changes in mycorrhizal fungal communities, that these changes may be involved in the rotation effect on soil productivity, and that design of cropping systems should take mycorrhizal fungal communities into consideration.     

Some Remarks on the Socio-Cultural Background of Restoration Ecology

Restoration ecology plays an important role in nature conservation policy in Europe today. It establishes the scientific basis for restoring ecosystems altered or destroyed by man to a more “natural” state. The goals of restoration ecology can generally be described in terms of increased biodiversity, enhanced water retention capacity, avoidance of soil erosion, etc. In practice, however, a discrepancy exists between the high ideals of restoration goals and reality, where one often encounters limiting factors. These limiting factors can include the conflict between different restoration goals, the unpredictability of restoration goals owing to long‐term effects and stochastic events, the insufficient social acceptance of landscape changes during restoration processes, and the use of restoration processes themselves (e.g., undisturbed succession, certain management measures like impoverishment of fertilized areas) as restoration goals in place of a certain resource quality (such as species composition, population sizes, water quality). Two examples from southern Germany show that restoration goals in European cultural landscapes can only be implemented successfully when they are integrated into the respective land use systems.     

Extraction of free amino acids from tomato leaves

Conditions for extraction of free amino acids from tomato leaves were examined. Two methods of sample preservation were also tested. Best results were obtained when samples were preserved by lyophilization and extracted by Soxhlet for 6 h at 40°C at a ratio of 1 g plant material/80 mL 80% (v/v) ethanol.     

Constant Pharmacologic Effect and Chronopharmacology: Theoretical Aspects

The theoretical drug infusion rates requisite to obtain a constant pharmacologic effect are determined taking into account chronopharmacologic phenomena. The introduction of chronopharmacology into pharmacokinetic theory leads to a clocktime-dependent infusion rate. The infusion modulation depends both on type of chronophenomenon, chronopharmacokinetics or chronestesy, and plasma clearance rate of the drug. In the presence of chronestesy of a biosystem the pharmacologic effect can be maintained constant only when plasma drug clearance is fast enough to allow an adequate modulation of the plasma drug concentration. Although the established equations proceed from theoretical concept they could be useful for programming drug delivery systems.