1,721,476 research outputs found
Oribatid mites show that soil food web complexity and close aboveground-belowground linkages emerged in the early Paleozoic
No full textDispersal patterns of oribatid mites across habitats and seasons
No full textAbstract Oribatid mites are tiny arthropods that are common in all soils of the world; however, they also occur in microhabitats above the soil such as lichens, mosses, on the bark of trees and in suspended soils. For understanding oribatid mite community structure, it is important to know whether they are dispersal limited. The aim of this study was to investigate the importance of oribatid mite dispersal using Malaise traps to exclude sole passive wind-dispersal. Oribatid mite communities were collected over a 3-year period from five habitat types (coniferous forests, deciduous forests, mixed forests, meadows, bog/heathlands sites) and three seasons (spring, summer, autumn) in Sweden. Mites entered traps either by walking or by phoresy, i.e., by being attached to flying insects. We hypothesized (1) that oribatid mite communities in the traps differ between habitats, indicating habitat-limited dispersal, and (2) that oribatid mite communities differ among seasons suggesting that dispersal varies due to changing environmental conditions such as moisture or resource availability. The majority of the collected species were not typically soil-living species but rather from habitats such as trees, lichens and mosses (e.g., Carabodes labyrinthicus, Cymbaeremaeus cymba, Diapterobates humeralis and Phauloppia lucorum ) indicating that walking into the traps or entering them via phoresy are of greater importance for aboveground than for soil-living species. Overall, oribatid mite communities collected in the traps likely originated from the surrounding local habitat suggesting that long distance dispersal of oribatid mites is scarce. Significant differences among seasons indicate higher dispersal during warm and dry periods of the year. Notably, 16 species of oribatid mites collected in our study were sampled for the first time in Sweden. This study also demonstrates that Malaise traps are a meaningful tool to investigate spatial and temporal patterns of oribatid mite communities.Abstract Oribatid mites are tiny arthropods that are common in all soils of the world; however, they also occur in microhabitats above the soil such as lichens, mosses, on the bark of trees and in suspended soils. For understanding oribatid mite community structure, it is important to know whether they are dispersal limited. The aim of this study was to investigate the importance of oribatid mite dispersal using Malaise traps to exclude sole passive wind-dispersal. Oribatid mite communities were collected over a 3-year period from five habitat types (coniferous forests, deciduous forests, mixed forests, meadows, bog/heathlands sites) and three seasons (spring, summer, autumn) in Sweden. Mites entered traps either by walking or by phoresy, i.e., by being attached to flying insects. We hypothesized (1) that oribatid mite communities in the traps differ between habitats, indicating habitat-limited dispersal, and (2) that oribatid mite communities differ among seasons suggesting that dispersal varies due to changing environmental conditions such as moisture or resource availability. The majority of the collected species were not typically soil-living species but rather from habitats such as trees, lichens and mosses (e.g., Carabodes labyrinthicus, Cymbaeremaeus cymba, Diapterobates humeralis and Phauloppia lucorum ) indicating that walking into the traps or entering them via phoresy are of greater importance for aboveground than for soil-living species. Overall, oribatid mite communities collected in the traps likely originated from the surrounding local habitat suggesting that long distance dispersal of oribatid mites is scarce. Significant differences among seasons indicate higher dispersal during warm and dry periods of the year. Notably, 16 species of oribatid mites collected in our study were sampled for the first time in Sweden. This study also demonstrates that Malaise traps are a meaningful tool to investigate spatial and temporal patterns of oribatid mite communities
18th Workshop on Automotive Software Engineering (ASE’21)
No full textSoftware-based systems play an increasingly important role and enable most of the innovations in modern cars. This workshop deals with various topics related to the development of automotive software and discusses suitable methods, techniques, and tools necessary to master the most current challenges researchers and practitioners are facing
Evidence for Wolbachia in leafhoppers of the genus Eupteryx with intersexual morphotypes
No full textLeafhoppers (Hemiptera Cicadellidae Typhlocybinae) of the genus Eupteryx are important pests on medical and culinary herbs including sage (Salvia officinalis L., Lamiaceae), causing severe economic damage. Individuals of Eupteryx decemnotata Rey and Eupteryx melissae Curtis show a modified genital morphology at two geographically distant populations in Germany (Bonn and Gottingen). Typical female and male sexual characters are merged. In another species of Typhlocybinae a similar intersexual phenotype, representing feminized males, was explained by Wolbachia infection. We investigated E. decemnotata and E. melissae from both locations for infection by a molecular screening study (PCR) with three Wolbachia specific genes (16S rRNA, ftsZ, wsp). The screening strongly supports Wolbachia infections in both host species in Gottingen and in E. melissae from Bonn. Phylogenetic analyses of the ftsZ, wsp and the host-specific COI gene indicate a single infection in E. melissae, but infection with two different strains in E. decemnotata and host-mediated distribution of Wolbachia. Further, the data indicate horizontal Wolbachia transmission between these leafhopper species. This is the first study demonstrating the presence of Wolbachia in Eupteryx leaf-hoppers. Rapid spread of Wolbachia in Eupteryx populations can potentially threaten sage cultivations if morphologically modified individuals represent feminized males, thereby increasing the reproductive potential of infected populations. We discuss possible implications of Wolbachia infection inducing a feminoid phenotype for the population dynamics of leafhopper pests.Bundesprogramm Okologischer Landbau (BOL); University of Bon
A core calculus for dynamic delta-oriented programming
No full textDelta-oriented programming (DOP) is a flexible approach to the implementation of software product lines (SPLs). Delta-oriented SPLs consist of a code base (a set of delta modules encapsulating changes to object-oriented programs) and a product line declaration (providing the connection of the delta modules with the product features). In this paper, we present a core calculus that extends DOP with the capability to switch the implemented product configuration at runtime. A dynamic delta-oriented SPL is a delta-oriented SPL with a dynamic reconfiguration graph that specifies how to switch between different feature configurations. Dynamic DOP supports also (unanticipated) software evolution such that at runtime, the product line declaration, the code base and the dynamic reconfiguration graph can be changed in any (unanticipated) way that preserves the currently running product, which is essential when evolution affects existing features. The type system of our dynamic DOP core calculus ensures that the dynamic reconfigurations lead to type safe products and do not cause runtime type errors
Evidence for Wolbachia in leafhoppers of the genus Eupteryx with intersexual morphotypes
No full textLeafhoppers (Hemiptera Cicadellidae Typhlocybinae) of the genus Eupteryx are important pests on medical and culinary herbs including sage (Salvia officinalis L., Lamiaceae), causing severe economic damage. Individuals of Eupteryx decemnotata Rey and Eupteryx melissae Curtis show a modified genital morphology at two geographically distant populations in Germany (Bonn and Gottingen). Typical female and male sexual characters are merged. In another species of Typhlocybinae a similar intersexual phenotype, representing feminized males, was explained by Wolbachia infection. We investigated E. decemnotata and E. melissae from both locations for infection by a molecular screening study (PCR) with three Wolbachia specific genes (16S rRNA, ftsZ, wsp). The screening strongly supports Wolbachia infections in both host species in Gottingen and in E. melissae from Bonn. Phylogenetic analyses of the ftsZ, wsp and the host-specific COI gene indicate a single infection in E. melissae, but infection with two different strains in E. decemnotata and host-mediated distribution of Wolbachia. Further, the data indicate horizontal Wolbachia transmission between these leafhopper species. This is the first study demonstrating the presence of Wolbachia in Eupteryx leaf-hoppers. Rapid spread of Wolbachia in Eupteryx populations can potentially threaten sage cultivations if morphologically modified individuals represent feminized males, thereby increasing the reproductive potential of infected populations. We discuss possible implications of Wolbachia infection inducing a feminoid phenotype for the population dynamics of leafhopper pests.Bundesprogramm Okologischer Landbau (BOL); University of Bon
Arthropod colonization of land - Linking molecules and fossils in oribatid mites (Acari, Oribatida)
No full textTerrestrial fossils that document the early colonization of land are scarce for > 100 my after the Cambrian explosion. This raises the question whether life on land did not exist or just did not fossilize. With a molecular dating technique, we analyzed the origin of terrestrial chelicerate microarthropods (Acari, Oribatida) which have a fossil record since the Middle Devonian that is exceptional among soil animals. Our results suggest that oribatid mites originated in the Precambrian (571 +/- 37 mya) and that the radiation of basal groups coincides with the gap in the terrestrial fossil record between the Cambrian explosion and the earliest fossilized records of continental ecosystems. Further, they suggest that the colonization of land started via the interstitial, similar to 150 my earlier than the oldest fossils of terrestrial ecosystems. Overall, the results imply that omnivorous and detritivorous arthropods formed a major component in early terrestrial food webs, thereby facilitating the invasion of terrestrial habitats by later colonizers of higher trophic levels. (C) 2010 Elsevier Inc. All rights reserved.German Research Foundation (DFG); Darmstadt University of Technolog
Skill-Based Verification of Cyber-Physical Systems
No full textThis work has been accepted at the 23rd International Conference on Fundamental Approaches to Software Engineering, held as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The increase of complexity in modeling cyber-physical systems poses a challenge for formally ensuring their functional correctness. Lack of expert knowledge and scalability are two limiting factors that prohibit a seamless integration into today's software engineering processes. To address this challenge, we propose to adopt and formalize the notion of skill graphs, an abstract and easy-to-use modeling notion for representing automated vehicle driving maneuvers. For formally verifying that skill graphs are well-formed and comply with a given set of safety requirements, we incorporate hybrid programs into our formalization. Hybrid programs constitute a program notion for cyber-physical systems on the basis of differential dynamic logic, which enables deductive and compositional verification following the idea of Hoare-style reasoning. That is, simpler verified skill graphs can be combined to exhibit complex maneuvers while validity is retained (i.e., without the need of re-verification). To showcase the benefits of our theoretical considerations, we implemented our framework in an open-source tool named Skeditor and conducted a case study exhibiting an automatic vehicle follow mode
Tool Support for Correctness-by-Construction
No full textThis work was published in International Conference on Fundamental Approaches to Software Engineering 2019. We tackled a fundamental problem of missing tool support of the correctness-by-construction (CbC) methodology that was proposed by Dijsktra and Hall and revised to a light-weight and more amenable version by Kourie and Watson. Correctness-by-construction (CbC) is an incremental approach to create programs using a set of small, easily applicable refinement rules that guarantee the correctness of the program with regard to its pre- and postcondition specifications. Our goal was to implement a functional and user-friendly IDE, so that developers will adapt to the CbC approach and benefit from its advantages (e.g., defects can be easily tracked through the refinement structure of the program). The tool has a hybrid textual and graphical IDE that programmers can use to refine a specification to a correct implementation. The textual editor fits to programmers that want to stay in their familiar environment, while the graphical editor highlights the refinement structure of the program to give visual feedback if errors occur using KeY as verification backend. The tool was evaluated regarding feasibility and effort to develop correct programs. Here, slight benefits in comparison to a standard verification approach were discovered
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