86 research outputs found
A Processual Perspective on Whole-Class-Scaffolding in Business Education
Context: Scaffolding is a form of process-adaptive learning support that is relevant in numerous contexts, including informal learning, workplace learning as well as school teaching. While scaffolding can be well conceptualised for individual learning situations (especially for tutoring situations), there is a difficulty in measuring process adaptivity in heterogeneous learning groups, such as school classes. Approach: In this paper, we develop a measurement method that targets the deep structure of teaching and learning in whole class settings. Processes of shared knowledge constructions are taken into account, since whole-class-scaffolding (WCS) means to shape and develop common or joint knowledge spaces rather than to scaffold a multitude of individual construction processes at the same time. To achieve a coding procedure for WCS interactions, we integrate scaffolding principles and principles of dialogic teaching and explicated a set of rules that can be correlated to the quality of WCS-episodes rated on distinct Likert scales. Results: The measurement method developed in the paper provides a solution to the problem of how to measure process-adaptive learning support that is not only related to individual learners, but is directed at a heterogeneous group of learners in which different support needs may be present simultaneously. The coding procedure systematically links scaffolding principles and principles of dialogic teaching and enables us to capture the dynamics of teaching and learning processes in larger group settings. In this respect, concepts such as joint- and common space, representing entities to which WCS refers, are operationalised. Conclusions: When methods for measuring the dynamics of teaching and learning processes are available, research on instructional support is no longer limited to global ratings of whole learning units. Furthermore, the codings allow for a more fine-grained analysis of trajectories of scaffolding interactions. Such an analysis reveals information about local specifics of WCS that can explain further learning differences between students and that can be used to derive implications for effective instructional techniques
A processual perspective on whole-class-scaffolding in business education
Context: Scaffolding is a form of process-adaptive learning support that is relevant in numerous contexts, including informal learning, workplace learning as well as school teaching. While scaffolding can be well conceptualised for individual learning situations (especially for tutoring situations), there is a difficulty in measuring process adaptivity in heterogeneous learning groups, such as school classes. Approach: In this paper, we develop a measurement method that targets the deep structure of teaching and learning in whole class settings. Processes of shared knowledge constructions are taken into account, since whole-class-scaffolding (WCS) means to shape and develop common or joint knowledge spaces rather than to scaffold a multitude of individual construction processes at the same time. To achieve a coding procedure for WCS interactions, we integrate scaffolding principles and principles of dialogic teaching and explicated a set of rules that can be correlated to the quality of WCS-episodes rated on distinct Likert scales. Results: The measurement method developed in the paper provides a solution to the problem of how to measure process-adaptive learning support that is not only related to individual learners, but is directed at a heterogeneous group of learners in which different support needs may be present simultaneously. The coding procedure systematically links scaffolding principles and principles of dialogic teaching and enables us to capture the dynamics of teaching and learning processes in larger group settings. In this respect, concepts such as joint- and common space, representing entities to which WCS refers, are operationalised. Conclusions: When methods for measuring the dynamics of teaching and learning processes are available, research on instructional support is no longer limited to global ratings of whole learning units. Furthermore, the codings allow for a more fine-grained analysis of trajectories of scaffolding interactions. Such an analysis reveals information about local specifics of WCS that can explain further learning differences between students and that can be used to derive implications for effective instructional techniques. (DIPF/Orig.
Investigation of mutants and substrates of the Arabidopsis SUMO conjugating system
SUMOylation is a posttranslational modification of proteins that is found in the eukaryotic kingdom, but not in bacteria or archeae. During this process, SUMO, the Small Ubiquitin related modifier protein, is covalently attached onto its targets via an enzymatic cascade. SUMOylation can prevent or induce other modifications of the substrate, can lead to conformational changes and generates or abolishes binding interfaces. SUMOylation can therefore change the localization, activity, interactions or life span of a protein. Although SUMOylation is vital in the model plant Arabidopsis thaliana (Saracco et al., 2007), only little is known about regulation and substrates of SUMO conjugation, as the temporary nature of this modification and the fact that only a small subset of substrate is modified at a given time, makes the study of SUMOylation in plants extremely difficult. In this work, several aspects of Arabidopsis SUMOylation are discussed: � An in vitro SUMOylation assay that utilizes plant recombinant proteins was developed. This system allows quick analysis of potential SUMOylation enzymes and substrates in vitro. � The features of a SUMO1 variant, SUMO1 Q90A, in which a conserved glutamine residue at position -4 from the carboxyl terminus is changed to alanine, were analyzed in vitro. It was shown that this mutant variant leads to increased conjugate stability towards Early in Short Days 4 (ESD4), a major SUMO protease of Arabidopsis. As SUMO1 Q90A did not differ during conjugation from the wild type SUMO1 in vitro, this variant might be a valuable tool for future experiments to generate SUMOylated proteins, which are easier to detect and to analyze due to increased stability. � Analysis of the potential SUMO ligases PIAS-LIKE1 (PIL1) and PIAS-LIKE2 (PIL2) indicated a slight contribution to bulk SUMO conjugation and only a minor role in flowering time regulation compared to the already well described SUMO ligase SIZ1, strengthening the importance of SIZ1 as major Arabidopsis SUMO ligase. � Plants with mutation in the SUMO protease ESD4 have growth defects with similarity to those of plants mutated in SIZ1. In contrast to siz1 mutants, however, the growth defect of esd4 mutants is not due to altered levels of the stress hormone salicylic acid. Furthermore, studies of the related SUMO protease Early in Short Days-Like1 (EL1) demonstrated that the latter enzyme does not localize to the nucleus if transiently expressed in Nicotiana benthamiana, and plays no obvious role in the regulation of flowering time, as el1 mutants flower at a time similar to wild type. However, an el1 mutation in the background of ecotype Wassilwskija might cause an altered tissue composition in the shoot. � Analysis of the type III effector protein Factor X of the plant pathogen Xanthomonas campestris (in cooperation with Prof. Ulla Bonas and Robert Szczesny, University Halle) indicated no in vitro activity of this protein as SUMO, Rub1 or Ubiquitin protease. The broad variety of aspects discussed in this work emphasizes the importance and complexity of Arabidopsis SUMOylation and indicates that the understanding of this modification in plants can only be achieved by further studies and identification of in vivo SUMO substrates. In future the SUMOylation assay system, developed in this work, and the described SUMO1 Q90A variant might help to accomplish these tasks
Thinking out of the Box! – Design-Thinking zur Digitalisierung in der kaufmännischen Berufsausbildung
Comparisons among the five ground-motion models developed using RESORCE for the prediction of response spectral accelerations due to earthquakes in Europe and the Middle East
This article presents comparisons among the five ground-motion models described in other articles within this special issue, in terms of data selection criteria, characteristics of the models and predicted peak ground and response spectral accelerations. Comparisons are also made with predictions from the Next Generation Attenuation (NGA) models to which the models presented here have similarities (e.g. a common master database has been used) but also differences (e.g. some models in this issue are nonparametric). As a result of the differing data selection criteria and derivation techniques the predicted median ground motions show considerable differences (up to a factor of two for certain scenarios), particularly for magnitudes and distances close to or beyond the range of the available observations. The predicted influence of style-of-faulting shows much variation among models whereas site amplification factors are more similar, with peak amplification at around 1s. These differences are greater than those among predictions from the NGA models. The models for aleatory variability (sigma), however, are similar and suggest that ground-motion variability from this region is slightly higher than that predicted by the NGA models, based primarily on data from California and Taiwan
Comparisons among the five ground-motion models developed using RESORCE for the prediction of response spectral accelerations due to earthquakes in Europe and the Middle East
This article presents comparisons among the five ground-motion models described in other articles within this special issue, in terms of data selection criteria, characteristics of the models and predicted peak ground and response spectral accelerations. Comparisons are also made with predictions from the Next Generation Attenuation (NGA) models to which the models presented here have similarities (e.g. a common master database has been used) but also differences (e.g. some models in this issue are nonparametric). As a result of the differing data selection criteria and derivation techniques the predicted median ground motions show considerable differences (up to a factor of two for certain scenarios), particularly for magnitudes and distances close to or beyond the range of the available observations. The predicted influence of style-of-faulting shows much variation among models whereas site amplification factors are more similar, with peak amplification at around 1s. These differences are greater than those among predictions from the NGA models. The models for aleatory variability (sigma), however, are similar and suggest that ground-motion variability from this region is slightly higher than that predicted by the NGA models, based primarily on data from California and Taiwan
Distinct roles for Arabidopsis SUMO protease ESD4 and its closest homolog ELS1
SUMO conjugation affects a broad range of processes in Arabidopsis thaliana, including flower initiation, pathogen defense, and responses to cold, drought and salt stress. We investigated two sequence-related SUMO-specific proteases that are both widely expressed and show that they differ significantly in their properties. The closest homolog of SUMO protease ESD4, ESD4-LIKE SUMO PROTEASE 1 (ELS1, alternatively called AtULP1a) has SUMO-specific proteolytic activity, but is functionally distinct from ESD4, as shown by intracellular localization, mutant phenotype and heterologous expression in yeast mutants. Furthermore, we show that the growth defects caused by loss of ESD4 function are not due to increased synthesis of the stress signal salicylic acid, as was previously shown for a SUMO ligase, indicating that impairment of the SUMO system affects plant growth in different ways. Our results demonstrate that two A. thaliana SUMO proteases showing close sequence similarity have distinct in vivo functions
Arabidopsis thaliana SPF1 and SPF2 are nuclear-located ULP2-like SUMO proteases that act downstream of SIZ1 in plant development
Post-translational modifiers such as the small ubiquitin-like modifier (SUMO) peptide act as fast and reversible protein regulators. Functional characterization of the sumoylation machinery has determined the key regulatory role that SUMO plays in plant development. Unlike components of the SUMO conjugation pathway, SUMO proteases (ULPs) are encoded by a relatively large gene family and are potential sources of specificity within the pathway. This study reports a thorough comparative genomics and phylogenetic characterization of plant ULPs, revealing the presence of one ULP1-like and three ULP2-like SUMO protease subgroups within plant genomes. As representatives of an under-studied subgroup, Arabidopsis SPF1 and SPF2 were subjected to functional characterization. Loss-of-function mutants implicated both proteins with vegetative growth, flowering time, and seed size and yield. Mutants constitutively accumulated SUMO conjugates, and yeast complementation assays associated these proteins with the function of ScUlp2 but not ScUlp1. Fluorescence imaging placed both proteins in the plant cell nucleoplasm. Transcriptomics analysis indicated strong regulatory involvement in secondary metabolism, cell wall remodelling, and nitrate assimilation. Furthermore, developmental defects of the spf1-1 spf2-2 (spf1/2) double-mutant opposed those of the major E3 ligase siz1 mutant and, most significantly, developmental and transcriptomic characterization of the siz1 spf1/2 triple-mutant placed SIZ1 as epistatic to SPF1 and SPF2.We thank Mark Hochstrasser (Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA) for kindly providing the ulp1-ts yeast mutant strain. This research was funded by FEDER (through COMPETE), and by Fundacao para a Ciencia e Tecnologia (FCT), within the scope of project SUMOdulator (FCOMP-01-0124-FEDER-028459 and PTDC/BIA-PLA/3850/2012). PHC was supported by FCT (SFRH/BD/44484/2008). HA and FF were supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000007 and Norte-01-0145-FEDER-000008, respectively). The work was supported by FEDER through the COMPETE 2020-Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT, within the framework of projects 'Rede de Investigacao em Biodiversidade e Biologia Evolutiva' (POCI-01-0145-FEDER-006821) and 'Institute for Research and Innovation in Health Sciences' (POCI-01-0145-FEDER-007274). This research was also supported by a grant from the Spanish Ministerio de Ciencia y Tecnologia (AGL2016-75819-C2-1-R) and FEDER (PCQ, AGC, ERB)
- …