Verhalten von Kupfer, Zink und Cadmium in einem stark belasteten Kalkboden

Near a brass foundry, the soil is severely polluted by the heavy metals cadmium, copper, and zinc which have been emitted for more than 80 years. Lime and clay present in the soil result in high pH and high adsorption capacity, leading to a small mobility of the metals. Therefore, the heavy-metal pollution is localized in the upper 25 cm of the soil. The enrichment of the metals in the topsoil substantially decreases biological decomposition rate and breakdown of the litter. The fertility of the soil is disturbed and the meagre vegetation on the site is strongly polluted.The three metals differ in their binding forms and their mobility. Cadmium is particularly adsorbed in the diffuse layer of the cation exchanger or associated with carbonates, which results in a relatively high plant availability. On the other hand, the exchangeable amounts of copper and zinc are small. Main binding forms of these metals are association with carbonates or iron oxides and especially in the case of copper the complexation by humic substances. In the soil solution, hydrated ions are the main species of cadmium and zinc, whereas copper is almost exclusively complexed by dissolved organic matter (DOC). As hydrated ions are preferentially taken up by plants, the availability of cadmium and zinc is greater than that of copper

Medical ethnobotany of the Yucatec Maya: Healers' consensus as a quantitative criterion

Medical Ethnobotany of the Yucatec Maya: Healers' Consensus as a Quantitative Criterion. Economic Botany 53(2):144-160, 1999. There is an urgent need to obtain information on the relative importance of a taxon used medicinally as compared to others within the same culture. This was achieved through a documentation of the current indigenous medical uses of 320 species in three Yucatec Maya communities during 18 months of fieldwork. The 1549 individual reports documented were divided into nine groups, which classify indigenous uses. The frequency of usage of the individual plants reported was employed in the analysis of the ethnobotanical importance of the respective taxa. Species cited more frequently in a group of indigenous uses are regarded to be of greater ethnobotanical importance than those cited only by a few informants. In order to obtain information on possible biological, pharmacological and toxicological effects of some particularly important species, the scientific literature on these taxa was evaluated systematically. The study is the basis for phytochemical and pharmacological evaluations of the traditional use

Zapotec and Mixe use of Tropical Habitats for securing medicinal plants in MéXico

Medicinal plants are essential in the medical systems of the Mixe and Zapotec. In this study ethno-ecological strategies, employed by the two neighboring Indian groups in Mexico, for obtaining medicinal plants are analyzed. The indigenous classification of the environment is notably different from the Western one and distinguishes six dissimilar principal "zones” or land use types. Most ethnomedically important species are cultivated in the "house garden” or gathered in the community or its immediate surroundings. The house garden, for example, contributes 31.8% and 26.2% of all medical taxa for the Mixe and Zapotec, respectively. These ethnobotanical data on the indigenous uses indicate that anthropogenic types of vegetation yield the largest percentage of medicinal tax

Subcellular immunocytochemical analysis detects the highest concentrations of glutathione in mitochondria and not in plastids

The tripeptide glutathione is a major antioxidant and redox buffer with multiple roles in plant metabolism. Glutathione biosynthesis is restricted to the cytosol and the plastids and the product is distributed to the various organelles by unknown mechanisms. In the present study immunogold cytochemistry based on anti-glutathione antisera and transmission electron microscopy was used to determine the relative concentration of glutathione in different organelles of Arabidopsis thaliana leaf and root cells. Glutathione-specific labelling was detected in all cellular compartments except the apoplast and the vacuole. The highest glutathione content was surprisingly not found in plastids, which have been described before as a major site of glutathione accumulation, but in mitochondria which lack the capacity for glutathione biosynthesis. Mitochondria of both leaf and root cells contained 7-fold and 4-fold, respectively, higher glutathione levels than plastids while the density of glutathione labelling in the cytosol, nuclei, and peroxisomes was intermediate. The accuracy of the glutathione labelling is supported by two observations. First, pre-adsorption of the anti-glutathione antisera with glutathione reduced the density of the gold particles in all organelles to background levels. Second, the overall glutathione-labelling density was reduced by about 90% in leaves of the glutathione-deficient Arabidopsis mutant pad2-1 and increased in transgenic plants with enhanced glutathione accumulation. Hence, there was a strong correlation between immunocytochemical and biochemical data of glutathione accumulation. Interestingly, the glutathione labelling of mitochondria in pad2-1 remained very similar to wild-type plants thus suggesting that the high mitochondrial glutathione content is maintained in a situation of permanent glutathione-deficiency at the expense of other glutathione pools. High and constant levels of glutathione in mitochondria appear to be particularly important in cell survival strategies and it is predicted that mitochondria must have highly competitive mitochondrial glutathione uptake systems. The present results underline the suggestion that subcellular glutathione concentrations are not controlled by a global mechanism but are controlled on an individual basis and it is therefore not possible to conclude from global biochemical glutathione analysis on the status of the various organellar pool

Medicinal Flora of the Popoluca, Mexico: A botanical systematical perspective

We studied the medicinal plants used by the Popoluca of the Sierra de Santa Marta (eastern Mexico). Using Moerman's method of regression analysis we determined which ethnomedically used taxa are over-represented in the Popolucan pharmacopoeia (e.g., Asteraceae) and which are underrepresented (e.g., Orchidaceae). Moerman et al. (1999) found high correlation between the holarctic pharmacopoeias and assumed that apart from the relatedness of the northern floras a "global pattern of human knowledge" may account for this finding. Although the Popoluca dwell in a habitat dominated by a neotropical flora but intermixed with important holarctic elements, they include considerably fewer neotropical taxa in their pharmacopoeia as one would expect if the historical transmitted knowledge were influencing their selection. This finding confirms the theory stated by Moerman et al. However, the Popoluca include some neotropical taxa in their pharmacopoeia and thus a moderate correlation exists between the Popolucan pharmacopoeia and the neotropical pharmacopoeia analysed by Moerman et al. We therefore conclude that apart from historically transmitted knowledge about specific taxa the "global pattern of human knowledge” addressed by Moerman et al. is largely based on "common selection criteria.

Subcellular immunocytochemical analysis detects the highest concentrations of glutathione in mitochondria and not in plastids

The tripeptide glutathione is a major antioxidant and redox buffer with multiple roles in plant metabolism. Glutathione biosynthesis is restricted to the cytosol and the plastids and the product is distributed to the various organelles by unknown mechanisms. In the present study immunogold cytochemistry based on anti-glutathione antisera and transmission electron microscopy was used to determine the relative concentration of glutathione in different organelles of Arabidopsis thaliana leaf and root cells. Glutathione-specific labelling was detected in all cellular compartments except the apoplast and the vacuole. The highest glutathione content was surprisingly not found in plastids, which have been described before as a major site of glutathione accumulation, but in mitochondria which lack the capacity for glutathione biosynthesis. Mitochondria of both leaf and root cells contained 7-fold and 4-fold, respectively, higher glutathione levels than plastids while the density of glutathione labelling in the cytosol, nuclei, and peroxisomes was intermediate. The accuracy of the glutathione labelling is supported by two observations. First, pre-adsorption of the anti-glutathione antisera with glutathione reduced the density of the gold particles in all organelles to background levels. Second, the overall glutathione-labelling density was reduced by about 90% in leaves of the glutathione-deficient Arabidopsis mutant pad2- 1 and increased in transgenic plants with enhanced glutathione accumulation. Hence, there was a strong correlation between immunocytochemical and biochemical data of glutathione accumulation. Interestingly, the glutathione labelling of mitochondria in pad2-1 remained very similar to wild-type plants thus suggesting that the high mitochondrial glutathione content is maintained in a situation of permanent glutathione-deficiency at the expense of other glutathione pools. High and constant levels of glutathione in mitochondria appear to be particularly important in cell survival strategies and it is predicted that mitochondria must have highly competitive mitochondrial glutathione uptake systems. The present results underline the suggestion that subcellular glutathione concentrations are not controlled by a global mechanism but are controlled on an individual basis and it is therefore not possible to conclude from global biochemical glutathione analysis on the status of the various organellar pools

Ceasefires as bargaining instruments in intrastate conflicts: ceasefire objectives and their effects on peace negotiations

All conflict settlements involve a ceasefire, but not all ceasefires help settle conflicts. Despite the multifaceted – and often critical – role of ceasefires in intrastate conflicts, we know surprisingly little about them. In particular, we lack a systematic understanding of how state and non-state actors use ceasefires as part of a larger military or political process. This thesis seeks to shed light on the use of ceasefires as bargaining instruments and on how they shape the trajectory of a conflict. It investigates when and why conflict party leaders use what types of ceasefires, and how this affects progress in peace negotiations. The thesis consists of four parts. Part one introduces the analytical framework that guides the theory building and discusses the literature and research design. Part two investigates when, how and why battlefield dynamics affect progress towards a negotiated conflict settlement. Part three shows how, over the course of a bargaining process, the strategic goal of conflict party leaders evolves, and how this evolving goal drives the design of a ceasefire. Part four summarizes the findings and discusses their implications for our understanding of ceasefires as an integral part of the transition from war to peace. The theoretical and empirical contributions of this thesis demonstrate how, far from interrupting the bargaining process, ceasefires can fulfill important bargaining functions that shift over the course of a conflict.Security and Global Affair

Strategic and internal communication with sub-focus on generations : a juxtaposition of Swiss business practice and international literature

The significance of effective strategic and internal communication and their multipliers of meaningful relationships and productive work climates within organizations, and ultimately overall organizational success, are omnipresent in the international literature. Contemporaneously, the ongoing demographic shift challenges internal communication departments to assess the implications of generation management on their discipline. Despite all the concurrent theoretical intelligence compiled in the literature, there is little research conducted on the actual implementation in business. It could be identified that the fundamental organizational strategy predominantly guides strategic and internal communication. This strategy is found to be not merely confined to internal communication professionals, but spreads over all hierarchical and functional levels in the organizational structure. The entire workforce in daily interaction shapes reality through both horizontal and vertical communication under the ultimate directive to enable the company to fulfill its fundamental mission. Beyond that, it became clear that normative theoretical communication concepts often fail at practical implementation because they consume to many resources, are too complex to realize, or are simply not practical, all of which hold true for segmenting after generations in internal communication on a strategic level

Chromatographic Methods and Transport of Chemicals in Soils

Transport of chemicals in soils and groundwater aquifers has become an increasingly important field in hydrology and soil science. Much progress in this field originates from the picture of the soil as a giant chromatography column. Therefore, one uses successfully concepts borrowed from chromatography theory. The applicability of such ideas for the description of the transport of chemicals in the field is reviewed