Ein Autorenwerkzeug zur Konfiguration von eLearning-Argumentationsframeworks

Argumentationsfertigkeiten sind essentiell in vielen Bereichen des Lebens. Dies gilt sowohl auf privater als auch auf geschäftlicher Ebene. Daher spielt die Ausbildung von Argumentations-fertigkeiten eine zentrale Rolle. Eine Möglichkeit, diese Ausbildung zu unterstützen, sind com-puterbasierte Argumentationssysteme, die sich jedoch oftmals als zu unflexibel für den Einsatz über Domänengrenzen hinweg herausgestellt haben. Dieser Beitrag beschreibt das für ver-schiedene Domänen speziell konfigurierbare LASAD Argumentationsframework und zeigt, dass komplexe Konfigurationsmechanismen durch entsprechende Hilfsmittel beherrschbar bleiben können

Identification, characterization and molecular adaptation of class I redox systems for the production of hydroxylated diterpenoids

Background De novo production of multi-hydroxylated diterpenoids is challenging due to the lack of efficient redox systems. Results In this study a new reductase/ferredoxin system from Streptomyces afghaniensis (AfR·Afx) was identified, which allowed the Escherichia coli-based production of the trihydroxylated diterpene cyclooctatin, a potent inhibitor of human lysophospholipase. This production system provides a 43-fold increase in cyclooctatin yield (15 mg/L) compared to the native producer. AfR·Afx is superior in activating the cylcooctatin-specific class I P450s CotB3/CotB4 compared to the conventional Pseudomonas putida derived PdR·Pdx model. To enhance the activity of the PdR·Pdx system, the molecular basis for these activity differences, was examined by molecular engineering. Conclusion We demonstrate that redox system engineering can boost and harmonize the catalytic efficiency of class I hydroxylase enzyme cascades. Enhancing CotB3/CotB4 activities also provided for identification of CotB3 substrate promiscuity and sinularcasbane D production, a functionalized diterpenoid originally isolated from the soft coral Sinularia sp

Computer-Supported Argumentation Learning: A Survey of Teachers, Researchers, and System Developers

Abstract. Argumentation is omnipresent in our lives and therefore an important skill to learn. While classic face-to-face argumentation and debate has advantages in helping people learn to argue better, it does not scale up, limited by teacher time and availability. Computer-supported argumentation (CSA) is a viable alternative in learning to argue, currently increasing in popularity. In this paper, we present results from a survey we conducted with experts on argu-mentation learning systems, one which provides a glimpse on future directions

Coarse graining methods for spin net and spin foam models

We undertake first steps in making a class of discrete models of quantum gravity, spin foams, accessible to a large scale analysis by numerical and computational methods. In particular, we apply Migdal-Kadanoff and Tensor Network Renormalization schemes to spin net and spin foam models based on finite Abelian groups and introduce `cutoff models' to probe the fate of gauge symmetries under various such approximated renormalization group flows. For the Tensor Network Renormalization analysis, a new Gauss constraint preserving algorithm is introduced to improve numerical stability and aid physical interpretation. We also describe the fixed point structure and establish an equivalence of certain models.Comment: 39 pages, 13 figures, 1 tabl

Phylogenetic and Evolutionary Patterns in Microbial Carotenoid Biosynthesis Are Revealed by Comparative Genomics

BACKGROUND: Carotenoids are multifunctional, taxonomically widespread and biotechnologically important pigments. Their biosynthesis serves as a model system for understanding the evolution of secondary metabolism. Microbial carotenoid diversity and evolution has hitherto been analyzed primarily from structural and biosynthetic perspectives, with the few phylogenetic analyses of microbial carotenoid biosynthetic proteins using either used limited datasets or lacking methodological rigor. Given the recent accumulation of microbial genome sequences, a reappraisal of microbial carotenoid biosynthetic diversity and evolution from the perspective of comparative genomics is warranted to validate and complement models of microbial carotenoid diversity and evolution based upon structural and biosynthetic data. METHODOLOGY/PRINCIPAL FINDINGS: Comparative genomics were used to identify and analyze in silico microbial carotenoid biosynthetic pathways. Four major phylogenetic lineages of carotenoid biosynthesis are suggested composed of: (i) Proteobacteria; (ii) Firmicutes; (iii) Chlorobi, Cyanobacteria and photosynthetic eukaryotes; and (iv) Archaea, Bacteroidetes and two separate sub-lineages of Actinobacteria. Using this phylogenetic framework, specific evolutionary mechanisms are proposed for carotenoid desaturase CrtI-family enzymes and carotenoid cyclases. Several phylogenetic lineage-specific evolutionary mechanisms are also suggested, including: (i) horizontal gene transfer; (ii) gene acquisition followed by differential gene loss; (iii) co-evolution with other biochemical structures such as proteorhodopsins; and (iv) positive selection. CONCLUSIONS/SIGNIFICANCE: Comparative genomics analyses of microbial carotenoid biosynthetic proteins indicate a much greater taxonomic diversity then that identified based on structural and biosynthetic data, and divides microbial carotenoid biosynthesis into several, well-supported phylogenetic lineages not evident previously. This phylogenetic framework is applicable to understanding the evolution of specific carotenoid biosynthetic proteins or the unique characteristics of carotenoid biosynthetic evolution in a specific phylogenetic lineage. Together, these analyses suggest a "bramble" model for microbial carotenoid biosynthesis whereby later biosynthetic steps exhibit greater evolutionary plasticity and reticulation compared to those closer to the biosynthetic "root". Structural diversification may be constrained ("trimmed") where selection is strong, but less so where selection is weaker. These analyses also highlight likely productive avenues for future research and bioprospecting by identifying both gaps in current knowledge and taxa which may particularly facilitate carotenoid diversification

CITUC: AUTOMATISIERTE LÖSUNGSBEWERTUNG IM E-LEARNING DURCH KOLLABORATIVES FILTERN

Kollaborative Filtertechniken spielen im heutigen Web 2.0 eine Schlüsselrolle. Während ihr Einsatzgebiet bislang überwiegend im E-Commerce Bereich zu finden ist, besitzen sie auch Einsatzpotenzial im E-Learning. Das in diesem Artikel beschriebene CITUC-System kombiniert kollaboratives Filtern mit Peer Reviews, um Systemfeedback zu studentischen Aufgabenlösungen zu geben. Das webbasierte System wurde mit Erfolg begleitend zum Übungsbetrieb bei einer Vorlesung an der Technischen Universität Clausthal eingesetzt und übertrug damit die Erwartungen aus einer vorherigen Laborstudie in die Praxis

An Architecture for Intelligent CSCL Argumentation Systems

Argumentation is a key research area within CSCL. Yet, while many empirical studies investigating the educational benefits of various forms of collaborative argumentation have been conducted, there has not been much work done towards developing generic and reusable software architectures for collaborative argumentation that have the potential to reduce the development time for argumentation learning systems. This paper proposes a general architecture for intelligently supported collaborative argumentation systems