Partielle Ordnung

The complexity of ecosystems urges that the evaluation process should avoid an aggregation of information. The reason is that although mathematical modelling has made enormous progress (object oriented programming) there is still no ecologically reasonable function of quality. The technique to compare chemicals for example, even if they are characterized by many properties, is based on the generalization of the concept of order and the method of visualization by the using Hasse diagrams. By the example of six chemicals the procedure will be explained and it will be shown that a high hazard potential of chemicals is related to different properties, which cause different ecotoxicological consequences.     

Chemische Reaktionen von Chlorvinylarsinverbindungen (Lewisite)

2-Chlorovinylarsine dichloride (Lewisite I) react by room temperature quickly with alcohols in an equilibrium reaction to yield 2-Chlorovinylarsine chloride ether and 2-Chlorovinylarsine bisether. The reactions are not quantitative. The ethyl- and propylether are not stable. The ether were identified with mass spectrometry.     

Effects of the 2008 flood on economic performance and food security in Yemen: a simulation analysis

Extreme weather events such as floods and droughts can have devastating consequences for individual well being and economic development, in particular in poor societies with limited availability of coping mechanisms. Combining a dynamic computable general equilibrium model of the Yemeni economy with a household‐level calorie consumption simulation model, this paper assesses the economy‐wide, agricultural and food security effects of the 2008 tropical storm and flash flood that hit the Hadramout and Al‐Mahrah governorates. The estimation results suggest that agricultural value added, farm household incomes and rural food security deteriorated long term in the flood‐affected areas. Due to economic spillover effects, significant income losses and increases in food insecurity also occurred in areas that were unaffected by flooding. This finding suggests that while most relief efforts are typically concentrated in directly affected areas, future efforts should also consider surrounding areas and indirectly affected people.     

Size-exclusion high performance liquid chromatography of the dodecameric and hexameric forms of hemocyanin from Callinectes sapidus

The relationship between the polymeric composition of hemocyanin and environmental conditions could be described more thoroughly if there were a simple method for separating the dodecameric and hexameric forms of the protein. Such a method for the separation of these two forms of hemocyanin from Callinectes sapidus Rathbun using size-exclusion high performance liquid chromatography has been developed. The method uses columns with an exclusion limit of 1x10⁶ daltons and monitors the binuclear copper moiety by its absorbance at 337 nm. The application of the method was demonstrated by obtaining the dodecamer to hexamer ratios for 20 hemocyanin samples from freshly caught adult intermolt male C. sapidus. The ratios ranged from 1.9:1 to 7.3:1 and appeared to be normally distributed. This variation in the polymeric composition of hemocyanin (much greater than that attributable to the reproducibility of the assay) is apparently occurring in nature, contrary to previous reports that have indicated the ratio to lie within a narrow band for a given species.New address effective May 1, 1992: Department of Chemistry, University of California, Irvine, California 92717, USA     

Bewertungsansatz von Umweltmonitoring-Informationssystemen in Ballungsräumen

Comprehensive data on environmental monitoring programs concerned with air pollutants like ozone (O₃), nitrogen dioxide (NO₂), nitrogen oxide (NO), carbon dioxide (CO₂) und carbon monoxide (CO), and occassionally suspended dust, benzene and other environmental chemicals, are available on the free Internet. As different monitoring information systems exist in most states or big cities of the Federal Republic of Germany, a comparison of these systems with their pros and cons is of great interest to the public. Environmental air pollutant monitoring systems in 16 states of Germany are listed and evaluated by applying 5 evaluation criteria for the differentiation of these systems. Different data-analysis methods will be applied, the Hasse diagram technique, a method derived from discrete mathematics and the partially Ordered Scalogram Analysis with Coordinates (POSAC) method, a multivariate statistical approach. The important objects, the so-called maximal or minimal objects, are detected in both methods. The Internet-based environmental monitoring systems of the states of Berlin, Bremen, Saxony-Anhalt, Baden-Wurttemberg are rated good in the evaluation approaches, whereas the information systems of the states of Brandenburg, North Rhine-Westphalia, Saxony received a rather poor ranking. The attributes of DA, way of data presentation on the Internet, and ME, type and length of measurements, were pointed out in the data-analysis methods. Multivariate explorative statistical methods offer a comprehensive tool for the graphical analysis of data-matrices. The ranking of objects is given in an effective and graphically comprehensible manner using the Hasse diagram technique. The choice and preference of the methods is problem-driven. A combination of these different methods is envisaged in the authors’ future research.     

The genesis of Lofer cycles of the Dachstein Limestone, Northern Calcareous Alps, Austria

Peritidal carbonate platform Lofer cycles have been regarded as a record of sea-level oscillations driven by variations in the earth's orbit. Fresh analysis of a newly measured 700?m thick section from the Steinernes Meer is presented here. Estimation of stratigraphic completeness indicates that this sequence is only 0.75–9.5% complete, strongly suggesting that Milankovitch patterns are not preserved. Analysis of cycle thickness-frequency distributions reveals an exponential pattern, strongly suggestive of aperiodic, random deposition rather than periodic deposition in response to orbital forcing. Evidence for the importance of autocyclic processes (e.g. lateral migration of inter- to supratidal mudbanks and subtidal areas) and syn-sedimentary tectonic downfaulting events within this already active Late Triassic extensional zone is presented.     

Feto-amniotic shunting—report of the experience of four european centres

Few reports concerning intrauterine shunting are available. We investigated the impact of this method. In order to evaluate intrauterine shunting and the complication rate for different indications, we sent a questionnaire to all German-speaking level 3 centres. In four level 3 centres, 52 intrauterine catheters were inserted in 34 fetuses. The indications were uni- or bilateral hydrothorax in nine cases, cystic adenomatoid malformation of the lung in four cases, infravesical stenosis in 13 cases, and fetal ascites in eight cases. In three cases (6 per cent), difficulties occurred when the drain was inserted. In 15 cases (29 per cent), the function of the drain was reduced by dislocation or occlusion. The mortality rate caused by shunting was as high as eight per cent (four cases). The application of an intrauterine shunt currently represents a rarely performed ultrasound-guided therapeutic intervention in the fetus. In all cases, the indication for shunting is to avoid compression of normal tissue by cystic structures. A high complication rate restricts the application of drainage to selected cases.     

Molecular structures and associations of humic substances in the terrestrial environment

Here we show, for the first time, evidence of the primary molecular structures in humic substances (HS), the most abundant naturally occurring organic molecules on Earth, and their associations as mixtures in terrestrial systems. Multi-dimensional nuclear magnetic resonance (NMR) experiments show us that the major molecular structural components in the mixtures operationally defined as HS are aliphatic acids, ethers, esters and alcohols; aromatic lignin derived fragments; polysaccharides and polypeptides. By means of diffusion ordered spectroscopy, distinct diffusion coefficients consistent with relatively low molecular weight molecules were observed for all the components in the mixtures, and saccharides were the largest single class of component present. Liquid chromatography NMR confirmed that HS components can be easily separated and nuclear Overhauser effect (NOE) enhancements support the finding that the components are of relatively low molecular weight <~2,000 Da. The widely recognized properties of HS, i.e., characteristics indicative of crosslinked, macromolecular networks, can now be explained as aggregation of mixtures, most likely instigated by complexation with metal cations.     

Microbial in situ degradation of aromatic hydrocarbons in a contaminated aquifer monitored by carbon isotope fractionation

We present an approach for characterizing in situ microbial degradation using the 13C/12C isotope fractionation of contaminants as an indicator of biodegradation. The 13C/12C isotope fractionation of aromatic hydrocarbons was studied in anoxic laboratory soil percolation columns with toluene or o-xylene as the sole carbon and electron source, and sulfate as electron acceptor. After approximately 2 months' of incubation, the soil microbial community degraded 32 mg toluene l(-1) and 44 mg o-xylene l(-1) to less than 0.05 mg l(-1), generating a stable concentration gradient in the column. The 13C/12C isotope ratio in the residual non-degraded fraction of toluene and o-xylene increased significantly, corresponding to isotope fractionation factors (alphaC) of 1.0015 and 1.0011, respectively. When the extent of biodegradation in the soil column was calculated based on the measured isotope ratios (R(t)) and an isotope fractionation factor (alphaC=1.0017) obtained from a sulfate-reducing batch culture the theoretical residual substrate concentrations (C(t)) matched the measured toluene concentrations in the column. This indicated that a calculation of biodegradation based on isotope fractionation could work in systems like soil columns. In a field study, a polluted, anoxic aquifer was analyzed for BTEX and PAH contaminants. These compounds were found to exhibit a significant concentration gradient along an 800-m groundwater flow path downstream of the source of contamination. A distinct increase in the carbon isotope ratio (delta13C) was observed for the residual non-degraded toluene (7.2 per thousand ), o-xylene (8.1 per thousand ) and naphthalene fractions (1.2 per thousand ). Based on the isotope values and the laboratory-derived isotope fractionation factors for toluene and o-xylene, the extent to which the residual substrate fraction in the monitoring wells had been degraded by microorganisms was calculated. The results revealed significant biodegradation along the groundwater flow path. In the wells at the end of the plume, the bioavailable toluene and o-xylene fractions had been almost completely reduced by in situ microbial degradation. Although indane and indene showed decreasing concentrations downstream of the groundwater flow path, suggesting microbial degradation, their carbon isotope ratios remained constant. As the physical properties of these compounds are similar to those of BTEX compounds, the constant isotope values of indane and indene indicated that microbial degradation did not lead to isotope fractionation of all aromatic hydrocarbons. In addition, physical interaction with the aquifer material during the groundwater passage did not significantly alter the carbon isotope composition of aromatic hydrocarbons.