Untersuchungen zur Lipoxygenase-vermittelten chemischen Verteidigung: Oxylipine aus Diatomeen und dem Moos "Physcomitrella patens"

Chemische Verteidigungsstrategien der Diatomeen (Kieselalgen) werden als neuer Aspekt der Diatomeen/Kopepoden-Interaktion diskutiert, da eine diatomeenreiche maternale Ernährung die Embyrogenese von Kopepoden inhibieren kann. Nach Zellverletzung bilden Diatomeen aus C20-/C16-Polyenfettsäuren Lipoxygenase-vermittelt alpha,beta,gamma,delta-ungesättigte Aldehyde, die als teratogene Substanzen in Laborexperimenten identifiziert wurden. Um die ökologische Relevanz dieser Oxylipine zu untersuchen, wurde eine leistungsfähige GC-MS Analytik entwickelt, die eine in situ Derivatisierung mit Pentafluorobenzylhydroxylamin sowie eine zuverlässige Quantifizierung in Freilandversuchen erlaubt. In einem kombinierten Ansatz aus klassischen Fütterungsversuchen und chemisch analytischen Messungen wurde das Küstengewässer vor Roscoff (Bretagne, Frankreich) beprobt, um einen Überblick des Nahrungseinflusses auf die Eiablage und den Schlupferfolg von Calanus helgolandicus zu erhalten. Des weiteren wurde die Lipoxygenasechemie im Rahmen einer Reihenuntersuchungen an 51 Diatomeenarten und exemplarisch an dem genetisch zugänglichen Modelorganismus Physcomitrella patens untersucht

Assessment for problem-based learning

When designing a new educational unit on organisational behaviour, special attention was paid to the constructive alignment of the assessment procedure with the learning outcomes and educational concept. In order to optimise the fit with the principles and philosophy of problem-based learning, the assessment was designed to support the process of constructive, collaborative, contextual and self-directed learning. In a final two-hour session, each problembased learning team is required to analyse a case study and report their diagnosis and suggested interventions in a case study paper with an accompanying set of PowerPoint™ slides. Design and delivery of this innovative approach to summative team performance assessment are reported and results show that students appreciate the educational value of the approach and consider it enhances their conceptual skills and competence in contributing to constructive teamwork.Keywords: assessment design, assessment for learning, assessment mix, assessment session, constructive alignment, problem-based learning (PBL

Untersuchungen zur Lipoxygenase-vermittelten chemischen Verteidigung: Oxylipine aus Diatomeen und dem Moos "Physcomitrella patens"

Chemische Verteidigungsstrategien der Diatomeen (Kieselalgen) werden als neuer Aspekt der Diatomeen/Kopepoden-Interaktion diskutiert, da eine diatomeenreiche maternale Ernährung die Embyrogenese von Kopepoden inhibieren kann. Nach Zellverletzung bilden Diatomeen aus C20-/C16-Polyenfettsäuren Lipoxygenase-vermittelt alpha,beta,gamma,delta-ungesättigte Aldehyde, die als teratogene Substanzen in Laborexperimenten identifiziert wurden. Um die ökologische Relevanz dieser Oxylipine zu untersuchen, wurde eine leistungsfähige GC-MS Analytik entwickelt, die eine in situ Derivatisierung mit Pentafluorobenzylhydroxylamin sowie eine zuverlässige Quantifizierung in Freilandversuchen erlaubt. In einem kombinierten Ansatz aus klassischen Fütterungsversuchen und chemisch analytischen Messungen wurde das Küstengewässer vor Roscoff (Bretagne, Frankreich) beprobt, um einen Überblick des Nahrungseinflusses auf die Eiablage und den Schlupferfolg von Calanus helgolandicus zu erhalten. Des weiteren wurde die Lipoxygenasechemie im Rahmen einer Reihenuntersuchungen an 51 Diatomeenarten und exemplarisch an dem genetisch zugänglichen Modelorganismus Physcomitrella patens untersucht

Quantification of Dissolved and Particulate Polyunsaturated Aldehydes in the Adriatic Sea

Polyunsaturated aldehydes (PUA) are supposed to play critical roles in chemically-mediated plankton interactions. Laboratory studies suggest that they act as mediators of chemical defense and chemical communication. PUA are oxylipins containing an α,β,γ,δ–unsaturated aldehyde structure element and are mainly found in diatoms. We present here a detailed surface mapping of PUA during a spring bloom of the diatom Skeletonema marinoi in the Adriatic Sea. We monitored dissolved PUA, as well as particulate PUA, which are produced by phytoplankton after cell disintegration. Our survey revealed a patchy distribution of PUA and shows that at most stations S. marinoi is the major contributor to the overall PUA. Our data also suggest that lysis of a diatom bloom can contribute significantly to the dissolved PUA concentrations and that other producers, which are smaller in cell size compared to diatoms, have to be taken into account as well if the total PUA content of marine samples is considered. The analyses of samples collected in deeper water suggests that diatom contribution to PUA decreases with depth, while smaller-sized unidentified organisms take place as dominant contributors to the PUA concentrations

Problem-based learning in the first or second language: Does it make a difference?

Problem-based learning (PBL) is the key didactic approach in the curriculum of the Stenden Hotel Management School. Real-world problems are used to activate prior knowledge and to trigger a learning process aimed at expanding and elaborating students’ understanding and competences. Since the hotel school accommodates an international student population, the entire programme uses English as the medium for communication. For approximately 90% of our students, English is a second language. This paper reports on the effectiveness of using the mother tongue (language 1) in collaborative learning, as opposed to using the student’s second language. We did so by asking a group of 12 students, who all have Dutch as their first language to perform all PBL activities in English as they usually do. At a later stage, the same group was asked to do a similar task in Dutch. PBL sessions were videotaped in our PBL lab, transcribed and analysed. Utterances of students were divided into the following categories: (1) statements, (2) constructive statements, (3) arguments, (4) questions, (5) confirmations, (6) negations, and (7) source utterances. The utterance analysis was limited to the first five steps in a seven-step approach. The findings in this small-scale pilot show – in line with earlier research – that students mainly communicate factual statements, hardly ask questions, and seldom confirm each other’s contributions when using their second language. However, when the first language was used, scores were more positive. Further research should show whether or not this is a structural finding. It was a surprise to notice that the English session contained nine minutes of “reading from paper” out of 32 minutes of reporting. In the Dutch session “reading from paper/tablet/phone” was absent.Keywords: problem-based learning, second language, collaborative learning, verbal interactions, utterance analysis, Englishmedium educatio

A review of research about the psychology of hospitality management in three leading hospitality journals

This article reviewed research articles published in three leading hospitality journals — Cornell Hospitality Quarterly, International Journal of Hospitality Management and Journal of Hospitality and Tourism Research. Sixty published issues (20 issues per journal) with a total of 539 articles were reviewed. The key objective of this review was to identify articles which dealt with the psychology of hospitality management and to analyse key features of those articles. Findings of a content analysis show that approximately 40% of published articles dealt with psychological topics. The most frequently researched psychological issues were clustered into three main categories: customer behaviour, employee behaviour and managerial behaviour. For the analysed psychological articles, most were authored by two or three authors, mostly academics. The most common type of research approach was testing causal models. The majority of articles employed quantitative research designs and analyses. Key implications of this study include the call for stronger diversity in hospitality psychological research and methodological approaches, better linkages between research and practice, as well as the incorporation of hospitality psychology in hospitality management curricula