The evolutionary origin of auditory receptors in Tettigonioidea: the complex tibial organ of Schizodactylidae

Audition in insects is of polyphyletic origin. Tympanal ears derived from proprioceptive or vibratory receptor organs, but many questions of the evolution of insect auditory systems are still open. Despite the rather typical bauplan of the insect body, e.g., with a fixed number of segments, tympanal ears evolved at very different places, but only ensiferans have ears at the foreleg tibia, located in the tibial organ. The homology and monophyly of ensiferan ears is controversial, and no precursor organ was unambiguously identified for auditory receptors. The latter can only be identified by comparative study of recent atympanate taxa. These atympanate taxa are poorly investigated. In this paper, we report the neuroanatomy of the tibial organ of Comicus calcaris (Irish 1986), an atympanate Schizodactylid (splay-footed cricket). This representative of a Gondwana relict group has a tripartite sensory organ, homologous to tettigoniid ears. A comparison with morphology-based cladistic phylogeny indicates that the tripartite neuronal organization present in the majority of Tettigonioidea presumably preceded evolution of a hearing sense in the Tettigonioidea. Furthermore, the absence of a tripartite organ in Grylloidea argues against a monophyletic origin and homology of the cricket and katydid ears. The tracheal attachment of sensory neurons typical for ears of Tettigonioidea is present in C. calcaris and may have facilitated cooption for auditory function. The functional auditory organ was presumably formed in evolution by successive non-neural modifications of trachea and tympana. This first investigation of the neuroanatomy of Schizodactylidae suggests a non-auditory chordotonal organ as the precursor for auditory receptors of related tympanate taxa and adds evidence for the phylogenetic position of the group.     

Sovereign financial disaster risk management: The case of Mexico

In 2006, Mexico became the first transition country to transfer part of its public-sector natural catastrophe risk to the international reinsurance and capital markets. The Mexican case is of considerable interest to highly exposed transition and developing countries, many of which are considering similar transactions. Risk financing instruments can assure governments of sufficient post-disaster capital to provide emergency response, disaster relief to the affected population and repair public infrastructure. The costs of financial instruments, however, can greatly exceed expected losses, and for this reason it is important to closely examine their benefits and alternatives. This paper analyzes the Mexican case from the perspective of the risk cedent (the Ministry of Finance and Public Credit), which was informed by analyses provided by the International Institute for Applied Systems Analysis (IIASA). The rationale for a government to insure its contingent liabilities is presented along with the fiscal, legal and institutional context of the Mexican transaction. Using publicly available data, the paper scrutinizes the choice the authorities faced between two different risk-transfer instruments: reinsurance and a catastrophe bond. Making use of IIASA's catastrophe simulation model (CATSIM), this financial risk management decision is analyzed within the context of a public investment decision.     

Impact of a NO₂-regenerated diesel particulate filter on PAH and NPAH emissions from an EURO IV heavy duty engine

In this study the emissions of polycyclic aromatic hydrocarbons (PAH) and their nitro-derivates (NPAH) from a modern heavy duty engine were analysed. Focus was on the effects of the aftertreatment system. It consisted of an oxidation catalyst coupled to a diesel particulate filter (DPF). In such systems the process of PAH and NPAH degradation may compete with the NPAH formation. Scope of the study was to explain to which extent modern DPF could support the formation of highly mutagenic NPAH by nitration of pre-existing PAH. It was found that the diesel trap reduced the total amount of PAH and NPAH emitted both at low load and high load. Nevertheless, at low load the lower temperatures and the higher NO(2) concentration furnished better conditions for PAH nitration while they were more adverse to NPAH degradation. These effects were NPAH-specific. For these reasons, some NPAH like 3-nitrophenanthrene were still efficiently degraded but others were newly formed. For instance emissions of the highly toxic 1-benzo(a)pyrene and 6-nitrobenzo(a)pyrene where increased by a factor 15 at low load and, even if in lower amount, were formed also at high load. The super-mutagen 1,6-dinitropyrene, which was not present in raw exhaust, could be found only after the DPF, indicating a new formation. In regard to emissions from the active regeneration mode, tremendous high emissions of 1-nitropyrene were reported. More accurate investigation of such a regeneration mode would be of great interest for the future.     

Reestablishing Naturally Functioning Dunes on Developed Coasts

Common beach management practices reduce the ecological values of coastal dunes. Mechanical beach cleaning eliminates incipient dunes, habitat for nesting birds, seed sources for pioneer dune colonizers and food for fauna, and artificially small, stabilized foredunes reduce the variability in microenvironments necessary for biodiversity. Recent initiatives for reducing coastal hazards, protecting nesting birds, and encouraging nature-based tourism provide incentive for the development of a restoration program for beaches and dunes that is compatible with human use. Suggested changes in management practice include restricting or rerouting pedestrian traffic, altering beach-cleaning procedures, using symbolic fences to allow for aeolian transport while preventing trampling of dunes, and eliminating or severely restricting exotic species. Landforms will be more natural in function and appearance but will be more dynamic, smaller and in a different position from those in natural areas. Research needs are specified for ecological, geomorphological, and attitudinal studies to support and inform restoration planning.     

Bewertung der Umweltrelevanz von Arzneistoffen

Aim The aim of this work was to investigate, which human and veterinary pharmaceuticals are of high ecological relevance due to the input into the environment as well as with regard to the effects and behaviour in the environment. Furthermore, the state of knowledge concerning the ecologically relevant substances and the need of research was evaluated. Methods A two-step approach considering the criteria quantity of sold pharmaceuticals, concentrations, effects and fate in the environment was developed to identify the pharmaceuticals of potential ecological relevance. In a second step the identified individual substances and groups of substances were considered in more detail concerning metabolism, environmental behaviour and ecological effects. Results In a first step 29 out of approximate 2,700 licensed human pharmaceuticals and seven substances as well as three substance groups used in veterinary medicine were identified as potentially ecologically relevant. The detailed assessment in a second step lead to the conclusion, that of the human pharmaceuticals 9 substances as well as two substance groups concerning the environmental behaviour and seven substances concerning the effects are of high environmental relevance. Concerning the environmental behaviour six out of seven veterinary pharmaceuticals as well as three substance groups and only three substances concerning the ecological effects were classified as relevant for the environment. Discussion By means of the presented method it was possible to limit the scope of a wide spectrum of pharmaceuticals, so that a detailed assessment of only relevant active agents was possible. Nevertheless, it is a precondition that investigations concerning the occurrence, fate and effects of the individual compounds in the environment have been already carried out and published in the literature. Conclusions The method is suitable for a comprehensive assessment of the ecological relevance of pharmaceuticals, but for a lot of human and veterinary pharmaceuticals the data available in the literature are insufficient. Recommendations For a final extensive assessment of the environmental relevance for some of the human and veterinary pharmaceuticals more studies are necessary. Especially data concerning the environmental behaviour in water and soils, data from long-term-studies for the assessment of ecological effects and data concerning metabolites and mixtures of pharmaceutical compounds are lacking.     

A unique strategy of host colony exploitation in a parasitic ant: workers of<Emphasis Type="Italic"> Polyrhachis lama</Emphasis> rear their brood in neighbouring host nests

The formicine ant Polyrhachis lama is a social parasite, exploiting its ponerine host ant species Diacamma sp. In most social parasitic associations, the parasitic species are closely related to their host species group, evolving directly from independent ancestors of the host species. However, in the Polyrhachis lama–Diacamma sp. association, the associated species belong to different ant subfamilies. Based on preliminary field surveys, we had presumed that P. lama might have given up its reproductive division of labour, i.e. workers would be able to produce males as well as workers and females parthenogenetically. In this study, this hypothesis was disproved: Polyrhachis lama workers cannot be fertilized and are only able to produce males. In the host–parasite association originating from nests possessing a P. lama queen, workers penetrate surrounding Diacamma sp. nests, carrying brood for rearing within these satellite nests. In this peculiar way, a single P. lama colony is able to exploit several Diacamma sp. colonies simultaneously.     

Nematodentest

For the assessment of contaminated and remediated soils and substrates, and the estimation of chronic toxicity of soil contaminations, an ecotoxicological test was developed using the terrestrial nematodePanagrellus redivivus. The population dynamics expressed by the reproduction factor (VF) allows an estimation of soil quality within seven days. Due to the rapid generation time ofPanagrellus (< 5 d), the short test duration is considered to be sufficient. The suitability of this test duration is considered to be sufficient. The suitability of this test was evaluated by investigating soils which had been contaminated using applications of specific pollutants (lindane and PCB 52).     

Umwelterziehung im Chemieunterricht

Für den schulischen Chemieunterricht wurde die neue Konzeption für einen sonderabfallfreien Experimentalunterricht entwickelt, der ohne methodische Einschränkungen realisierbar ist und keine wesentlichen stofflichen Beschränkungen erfordert. Durch die konsequent praktizierte Handlungsorientierung wird er den Forderungen nach einer effektiven Umwelterzichung in besonderer Weise gerecht.     

Biodegradation of petroleum hydrocarbon vapors: laboratory studies on rates and kinetics in unsaturated alluvial sand

Predictions of natural attenuation of volatile organic compounds (VOCs) in the unsaturated zone rely critically on information about microbial biodegradation kinetics. This study aims at determining kinetic rate laws for the aerobic biodegradation of a mixture of 12 volatile petroleum hydrocarbons and methyl tert-butyl ether (MTBE) in unsaturated alluvial sand. Laboratory column and batch experiments were performed at room temperature under aerobic conditions, and a reactive transport model for VOC vapors in soil gas coupled to Monod-type degradation kinetics was used for data interpretation. In the column experiment, an acclimatization of 23 days took place before steady-state diffusive vapor transport through the horizontal column was achieved. Monod kinetic parameters Ks and vmax could be derived from the concentration profiles of toluene, m-xylene, n-octane, and n-hexane, because substrate saturation was approached with these compounds under the experimental conditions. The removal of cyclic alkanes, isooctane, and 1,2,4-trimethylbenzene followed first-order kinetics over the whole concentration range applied. MTBE, n-pentane, and chlorofluorocarbons (CFCs) were not visibly degraded. Batch experiments suggested first-order disappearance rate laws for all VOCs except n-octane, which decreased following zero-order kinetics in live batch experiments. For many compounds including MTBE, disappearance rates in abiotic batch experiments were as high as in live batches indicating sorption. It was concluded that the column approach is preferable for determining biodegradation rate parameters to be used in risk assessment models.