513 research outputs found

    Molecular convergence by differential domain acquisition is a hallmark of chromosomal passenger complex evolution

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    The chromosomal passenger complex (CPC) is a heterotetrameric regulator of eukaryotic cell division, consisting of an Aurora-type kinase and a scaffold built of INCENP, Borealin, and Survivin. While most CPC components are conserved across eukaryotes, orthologs of the chromatin reader Survivin have previously only been found in animals and fungi, raising the question of how its essential role is carried out in other eukaryotes. By characterizing proteins that bind to the Arabidopsis Borealin ortholog, we identified BOREALIN RELATED INTERACTOR 1 and 2 (BORI1 and BORI2) as redundant Survivin-like proteins in the context of the CPC in plants. Loss of BORI function is lethal and a reduced expression of BORI s causes severe developmental defects. Similar to Survivin, we find that the BORIs bind to phosphorylated histone H3, relevant for correct CPC association with chromatin. However, this interaction is not mediated by a BIR domain as in previously recognized Survivin orthologs but by an FHA domain, a widely conserved phosphate-binding module. We find that the unifying criterion of Survivin-type proteins is a helix that facilitates complex formation with the other two scaffold components and that the addition of a phosphate-binding domain, necessary for concentration at the inner centromere, evolved in parallel in different eukaryotic groups. Using sensitive similarity searches, we find conservation of this helical domain between animals and plants and identify the missing CPC component in most eukaryotic supergroups. Interestingly, we also detect Survivin orthologs without a defined phosphate-binding domain, likely reflecting the situation in the last eukaryotic common ancestor. </jats:p

    The role of individual and social variables in task performance.

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    This paper reports on a data-based study in which we explored - as part of a larger-scale British-Hungarian research project - the effects of a number of affective and social variables on foreign language (L2) learners’ engagement in oral argumentative tasks. The assumption underlying the investigation was that students’ verbal behaviour in oral task situations is partly determined by a number of non-linguistic and non-cognitive factors whose examination may constitute a potentially fruitful extension of existing task-based research paradigms. The independent variables in the study included various aspects of L2 motivation and several factors characterizing the learner groups the participating students were members of (such as group cohesiveness and intermember relations), as well as the learners’ L2 proficiency and ‘willingness to communicate’ in their L1. The dependent variables involved objective measures of the students’ language output in two oral argumentative tasks (one in the learners’ L1, the other in their L2): the quantity of speech and the number of turns produced by the speakers. The results provide insights into the interrelationship of the multiple variables determining the learners’ task engagement, and suggest a multi-level construct whereby some independent variables only come into force when certain conditions have been met

    Self-Regulation in a Web-Based Course: A Case Study

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    Little is known about how successful students in Web-based courses self-regulate their learning. This descriptive case study used a social cognitive model of self-regulated learning (SRL) to investigate how six graduate students used and adapted traditional SRL strategies to complete tasks and cope with challenges in a Web-based technology course; it also explored motivational and environmental influences on strategy use. Primary data sources were three transcribed interviews with each of the students over the course of the semester, a transcribed interview with the course instructor, and the students’ reflective journals. Archived course documents, including transcripts of threaded discussions and student Web pages, were secondary data sources. Content analysis of the data indicated that these students used many traditional SRL strategies, but they also adapted planning, organization, environmental structuring, help seeking, monitoring, record keeping, and self-reflection strategies in ways that were unique to the Web-based learning environment. The data also suggested that important motivational influences on SRL strategy use—self-efficacy, goal orientation, interest, and attributions—were shaped largely by student successes in managing the technical and social environment of the course. Important environmental influences on SRL strategy use included instructor support, peer support, and course design. Implications for online course instructors and designers, and suggestions for future research are offered

    Adaptability, Engagement, and Degree Completion:A Longitudinal Investigation of University Students

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    © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. University entry and the passage through university is a time of great change. The extent to which students are able to adjust to successfully navigate this change (adaptability) is likely to influence their academic outcomes. Prior research has identified a link between university students’ adaptability and academic achievement via behavioural engagement. The current longitudinal study extends this research by examining whether university students’ adaptability predicts degree completion via behavioural engagement. Undergraduate students (N = 186) were surveyed for their adaptability and behavioural engagement at degree commencement. Their completion status was extracted from the University Records System at the end of the degree. Findings showed that adaptability predicts both positive and negative behavioural engagement, and that negative (but not positive) behavioural engagement predicts degree completion. Adaptability was also found to influence degree completion indirectly via negative behavioural engagement. These findings hold important theoretical and practical implications for educators and researchers seeking to understand how students manage the transition to university and the extent to, and mechanisms by which students’ adaptability is associated with university degree completion

    Pleural aspergillosis complicated by recurrent pneumothorax: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Pneumothorax as the first symptom of pleural aspergillosis is rare.</p> <p>Case presentation</p> <p>A 31-year-old asthmatic Chinese man presented with recurrent spontaneous pneumothorax and underwent lobectomy due to persistent air leakage. Aspergillus was detected histopathologically in the visceral pleural cavity. He was treated with itraconazole at 200 mg a day, and nine months later he had no recurrent pneumothorax or aspergillus infection.</p> <p>Conclusion</p> <p>Recurrent pneumothorax may be a rare manifestation of aspergillus infection. Aspergillus species infection should be considered in the differential diagnosis of recurrent pneumothorax patients, particularly those with chronic lung disease.</p

    Enhancing Scientific Discovery Learning by Just-in-Time Prompts in a Simulation-Assisted Inquiry Environment

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    We investigated the effects of just-in-time guidance at various stages of inquiry learning by novice learners. Thirteen participants, randomly assigned to an intervention (n = 8) or control (n = 5) group, were observed as they learned about DC electric circuits using a web-based simulation. Just-in-time instructional prompts to observe, predict, explain, systematically test, collect evidence, and generate rules were strongly associated with diagnosing and correcting misconceptions, and constructing correct scientific concepts. Students’ repeated use of predictions, systematic testing, and evidence-coordinated reasoning often led to formulating new principles, generalizing from observed patterns, verifying comprehension, and experiencing “Aha!” moments. Just-in-time prompts helped learners manage embedded cognitive challenges in inquiry tasks, achieve a comprehensive understanding of the model represented in the simulation, and show significantly higher knowledge gain. Just-in-time prompts also promoted rejection of incorrect models of inquiry and construction of robust scientific mental models. The results suggest ways of customizing guidance to promote scientific learning within simulation environments

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    Using formative assessment to influence self- and co-regulated learning: the role of evaluative judgement

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    Recently, the concept of evaluative judgement has gained attention as a pedagogical approach to classroom formative assessment practices. Evaluative judgement is the capacity to be able to judge the work of oneself and that of others, which implies developing knowledge about one’s own assessment capability. A focus on evaluative judgement helps us to better understand what is the influence of assessment practices in the regulation of learning. In this paper, we link evaluative judgement to two self-regulated learning models (Zimmerman and Winne) and present a model on the effects on co-regulation of learning. The models help us to understand how students can be self-regulated through developing their evaluative judgement. The co-regulation model visualises how the learner can become more strategic in this process through teacher and peer assessment in which assessment knowledge and regulation strategies are shared with the learner. The connections we make here are crucial to strengthening our understanding of the influence of assessment practices on students’ learnin

    Supporting self-regulated learning

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    Self-regulated learning (SRL) competences are crucial for lifelong learning. Their cultivation requires the right balance between freedom and guidance during the learning processes. Current learning systems and approaches, such as personal learning environments, give overwhelming freedom, but also let weak learners alone. Other systems, such as learning management systems or adaptive systems, tend to institutionalise learners too much, which does not support the development of SRL competences. This chapter presents possibilities and approaches to support SRL by the use of technology. After discussing the theoretical background of SRL and related technologies, a formal framework is presented that describes the SRL process, related competences, and guidelines. Furthermore, a variety of methods is presented, how learners can be supported to learn in a self-regulated way
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