Konzeption und Evaluation eines computerunterstützten kooperativen Blockseminars zur Systematik der Blütenpflanzen

Der Einblick in die Systematik der Tiere und Pflanzen einschließlich Bestimmungsübungen gehört zur Biologie-Lehramtsausbildung vieler Hochschulen. In diesem Artikel wird ein computerunterstütztes Konzept vorgestellt, in dem Bestimmungsübungen und ein Überblick über das System der Blütenpflanzen mit Lehr- und Lernmethoden durchgeführt wurden, die sich an aktuellen Befunden der Kognitionspsychologie orientierten. Dies sind konkret die Vermittlung und Strukturierung des Inhaltsgebietes über ein Mind-Mapping-Verfahren, die Erarbeitung der Wissenseinheiten in Form des Gruppenpuzzle als kooperativer Lernform und die Freilandarbeit. Basis war die Selbstbestimmungstheorie von Deci & Ryan (1993). Letztere stellt die selbst bestimmte Tätigkeit als ein wichtiges Bedürfnis dar. Schwerpunkte dieses Ansatzes sind die Aspekte Autonomie erleben und Kompetenzerfahrung. Selbstbestimmte Formen der Handlungsregulation versprechen qualitativ hochwertige Lernergebnisse. Studierende des Blockseminars (n=31) wiesen höhere Werte im Hinblick auf die Skalen Interesse/Vergnügen, wahrgenommene Kompetenz und Anstrengung / Wichtigkeit auf, während Studierende der traditionellen Semester-Lehrveranstaltung (n=62) eine höhere Wahlfreiheit empfanden. Keine signifikanten Unterschiede ergaben sich bei der Skala Druck/Anpassung. Die Leistungen in der Akademischen Zwischenprüfung unterschieden sich nicht signifikant voneinander, allerdings wiesen die Studierenden aus dem Blockkurs weniger Fehler auf. Aus dieser Sicht bietet das Blockseminar vielerlei Vorteile. 25.02.2007 | Steffen SCHAAL & Christoph RANDLER (Ludwigsburg

Mutational analysis of the internal membrane proximal domain of the HIV glycoprotein C-terminus

AbstractThis study focuses on the long stretch of highly conserved amino acids in the membrane proximal part of the HIV-1 cytoplasmic tail (Env amino acids (aa) 706–718) upstream of the overlap with the tat and rev second coding exons. Changes in Env aa 713 and 715, although they did not affect Env function, abrogated replicative spread. Other amino acid substitutions, i.e., 706–712, 714 and 716, despite their conservation, did not result in defective replicative phenotypes even in primary peripheral blood lymphocytes. Our results point to their involvement in presently unrecognized essential Env functions pertinent only in in vivo. Interestingly, changes in the codons for residues 717–718 as well as some mutations in residues 714–716 abrogated Gag expression but still allowed expression of functional Env in a rev-independent manner. This could be due to the inactivation of a rev-regulated negative element within the respective nucleotide sequence (8354–8368)

A tudományos kommunikáció története a Journal des Scavans-tól az open access-ig

Background: The foamy viral genome encodes four central purine-rich elements localized in the integrase-coding region of pol. Previously, we have shown that the first two of these RNA elements (A and B) are required for protease dimerization and activation. The D element functions as internal polypurine tract during reverse transcription. Peters et al., described the third element (C) as essential for gag expression suggesting that it might serve as an RNA export element for the unspliced genomic transcript. Results: Here, we analysed env splicing and demonstrate that the described C element composed of three GAA repeats known to bind SR proteins regulates env splicing, thus balancing the amount of gag/pol mRNAs. Deletion of the C element effectively promotes a splice site switch from a newly identified env splice acceptor to the intrinsically strong downstream localised env 3′ splice acceptor permitting complete splicing of almost all LTR derived transcripts. We provide evidence that repression of this env splice acceptor is a prerequisite for gag expression. This repression is achieved by the C element, resulting in impaired branch point recognition and SF1/mBBP binding. Separating the branch point from the overlapping purine-rich C element, by insertion of only 20 nucleotides, liberated repression and fully restored splicing to the intrinsically strong env 3′ splice site. This indicated that the cis-acting element might repress splicing by blocking the recognition of essential splice site signals. Conclusions: The foamy viral purine-rich C element regulates splicing by suppressing the branch point recognition of the strongest env splice acceptor. It is essential for the formation of unspliced gag and singly spliced pol transcripts

How a Digital Educational Game can Promote Learning about Sustainability

Education for Sustainable Development (ESD) has become an essential issue for schools facing major challenges such as bridging the knowledge-action-gap. Interactive simulations could help to focus on action-oriented learning. As part of a design-based research (DBR) process, we investigated the learning potential of game elements within a digital educational game for ESD we are currently developing. The final game aims to convey specific aspects of ESD ranging from sustainable land use to personal power consumption. Seven groups of 2–3 secondary school students (9th and 10th grade, n = 18) played the educational game in an early prototype phase. Following the DBR approach, students were shown screenshots of specific game situations in subsequent group interviews to reveal their conceptions and conceptual developments regarding sustainability. To analyze the causes of possible learning processes, we used the retrospective query on the learning process and qualitative content analysis. The results indicate that the observed learning processes can be primarily traced back to feedback mechanisms and the visualization of processes that would be too complex and long-termed to be experienced by students in real-life. This is how a simulation game, which makes complex interrelations tangible, can contribute to ESD. The possibility to make decisions and act (digitally) within the game allowed students to experience immediate feedback and self-efficacy. Therefore, the easily accessible visualizations and the immediate feedback are essential elements for the final game. It appears however necessary to embed the game in well-structured reflective processes. The study also contributes to adaptive game-based learning as a growing branch of research in which game elements are adopted and adapted for learning based on learner characteristics and the thematic context

Perceived emotions of harmonic cadences

Harmonic cadences are chord progressions that play an important structural role in Western classical music – they demarcate musical phrases and contribute to the tonality. This study examines participants’ ratings of the perceived arousal and valence of a variety of harmonic cadences. Manipulations included the type of cadence (authentic, plagal, half, and deceptive), its mode (major or minor), its average pitch height (the transposition of the cadence), the presence of a single tetrad (a dissonant four-tone chord), and the mode (major or minor) of the cadence’s final chord. With the exception of average pitch height, the manipulations had only small effects on arousal. However, the perceived valence of major cadences was substantially higher than for minor cadences, and average pitch had a medium-sized positive effect. Plagal cadences, the inclusion of a tetrad, and ending on a minor chord all had weak negative effects for valence. The present findings are discussed in light of contemporary music theory and music psychology, as knowledge of how specific acoustic components and musical structures impact emotion perception in music is important for performance practice, and music-based therapies

Mobiles, ortsbezogenes Lernen in der Ernährungs- und Verbraucherbildung

Im MILE-Projekt werden digitale Technologien für mobile, ortsbezogene Lernangebote in der Ernährungs- und Verbraucherbildung (EVB) genutzt. Ziel ist es, mit sog. MILEGeogames Jugendliche für Themen der EVB zu sensibilisieren. Die im Projekt entwickelte MILE.Toolbox unterstützt Multiplikatoren bei der Erstellung von MILE-Geogames. Der Beitrag diskutiert das Potential des Ansatzes für die Ernährungs- und Verbraucherbildung. (DIPF/Orig.

Combining Active Learning and Reactive Control for Robot Grasping

peer reviewe

Limited complementarity between U1 snRNA and a retroviral 5′ splice site permits its attenuation via RNA secondary structure

Multiple types of regulation are used by cells and viruses to control alternative splicing. In murine leukemia virus, accessibility of the 5′ splice site (ss) is regulated by an upstream region, which can fold into a complex RNA stem–loop structure. The underlying sequence of the structure itself is negligible, since most of it could be functionally replaced by a simple heterologous RNA stem–loop preserving the wild-type splicing pattern. Increasing the RNA duplex formation between U1 snRNA and the 5′ss by a compensatory mutation in position +6 led to enhanced splicing. Interestingly, this mutation affects splicing only in the context of the secondary structure, arguing for a dynamic interplay between structure and primary 5′ss sequence. The reduced 5′ss accessibility could also be counteracted by recruiting a splicing enhancer domain via a modified MS2 phage coat protein to a single binding site at the tip of the simple RNA stem–loop. The mechanism of 5′ss attenuation was revealed using hyperstable U1 snRNA mutants, showing that restricted U1 snRNP access is the cause of retroviral alternative splicing

Mehr als eine Rechenmaschine. Computer im mathematisch-naturwissenschaftlichen Unterricht

Im mathematisch-naturwissenschaftlichen Unterricht kann der Computer verschiedene Funktionen als Werkzeug übernehmen. Er bietet beispielsweise die Möglichkeit, komplexe Berechnungen durchzuführen, abstrakte Sachverhalte zu veranschaulichen und mathematisch-naturwissenschaftliche Kontexte zu erforschen. Dabei ist der Computer in der Regel nicht nur Hilfsmittel, sondern auch Lerninhalt. Seine Nutzung muss ebenso erlernt werden wie die mathematischen oder naturwissenschaftlichen Fachinhalte. Unter anderem muss aus diesem Grund der Computereinsatz didaktisch-methodisch begründet und geplant sein, um Gefahren und Probleme der Computernutzung im Unterricht zu vermeiden. (DIPF/Orig.