A vertebrate crossveinless 2 homologue modulates BMP activity and neural crest cell migration

Previous work has revealed that proteins that bind to bone morphogenetic proteins (BMPs) and inhibit their signalling have a crucial role in the spatial and temporal regulation of cell differentiation and cell migration by BMPs. We have identified a chick homologue of crossveinless 2, a Drosophila gene that was identified in genetic studies as a promoter of BMP-like signalling. Chick Cv-2 has a conserved structure of five cysteine-rich repeats similar to those found in several BMP antagonists, and a C-terminal Von Willebrand type D domain. Cv-2 is expressed in the chick embryo in a number of tissues at sites at which elevated BMP signalling is required. One such site of expression is premigratory neural crest, in which at trunk levels threshold levels of BMP activity are required to initiate cell migration. We show that, when overexpressed, Cv-2 can weakly antagonise BMP4 activity in Xenopus embryos, but that in other in vitro assays Cv-2 can increase the activity of co-expressed BMP4. Furthermore, we find that increased expression of Cv-2 causes premature onset of trunk neural crest cell migration in the chick embryo, indicative of Cv-2 acting to promote BMP activity at an endogenous site of expression. We therefore propose that BMP signalling is modulated both by antagonists and by Cv-2 that acts to elevate BMP activity

Inferring surface time of Minke whales from inter-surfacing interval data using a hidden Markov model

Surfacing rate data of Minke whales is an important factor used in the abundance estimates of Minke whale (Balaenoptera acutorostrata) stocks, both in aerial and vessel based surveys. Today, most abundance estimates of Minke whales rely on VHF-transmitters data rather than visual data. Visual data collected from land has the advantage of being relatively cheap to collect, which allows data to be collected from a larger number of individuals while causing no effect on the surfacing rates of the animals being studied, hence limiting biases. In this study, individual follows of Minke whales were conducted from a land-based station in Faxaflói bay, Iceland, and data on inter-breath intervals (IBI) were collected. Two distinct dive types were present within the surfacing data, which we defined as regular dives and deep dives. Those emerged from two different biological processes: whales spending time at the surface and whales engaging in foraging activities. A hidden Markov model was used to identify and define the density distribution of IBI as the observation state of these two hidden diving processes. Regular dives had a mean surfacing interval of 43 seconds (SD=44.8) and deep dives had a mean surfacing interval of 155 seconds (SD=115.1). The transition probabilities between the two dive types were estimated, from which the relative proportion spent in each dive type could be inferred. Minke whales perform regular dives during 62% and deep dives during 38% of their time. The relative proportions spent in each dive type can be used as estimates of how much time a whale will be typically at the surface available to be detected during cue counting surveys and to estimate the odds that a whale is in a long dive and therefore unlikely to be detected. Data was also collected from commercial whalewatching boats in the same bay, and were analysed together with the land based data to measure the effect of whalewatching boat interaction on Minke whale surface intervals. The proportion of time spent in deep dives decreased from 38% to 14% during interactions with whalewatching boats, while regular dives increased from 62% to 86%. The inter-surfacing interval used in abundance estimates of Minke whales in the North Atlantic today is derived from VHF-transmitter data and is about 77 seconds. Our mean values of surface intervals lies below and above this mean, which raises the question if a single mean value of surfacing interval can be used to make reliable abundance estimates of Minke whales, as both the dive type and the presence of vessels is likely to affect this value

“Når man er tvunget ud i det, er det egentlig meget godt” Lektionsstudier og lærerarbejde – erfaringer fra et EVU-projekt

I denne artikel præsenteres en række resultater fra et naturfagligt udviklingsprojekt. Pro-jektet har i tre sjællandske kommuner arbejdet med at løfte læreres undervisningskompetencer i naturfagene. Vi viser i artiklen at det vi kalder en “de-privatisering af klasserummet” og ændring af lærerkulturen, er en nødvendighed for kompetenceudvikling understøttet af metoden lektionsstudier samt relevante stilladseringsværktøjer der kan rammesætte udviklingen af undervisningskompeten-cer – i dette tilfælde et såkaldt P-CKema. Desuden peger projektets empiri på at projekter der søger at udvikle undervisningskompetence i skolen, er komplekse og har brug for støtte og samarbejde mellem skolens strategiske, taktiske og didaktiske niveauer

Pesticide residues in food from Asia on the Norwegian market and the importance of efficient screening methods for pesticides

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Long-term follow-up study of work status among patients with work-related mental disorders referred to departments of occupational medicine in Denmark

OBJECTIVES: To describe the 5 year work status in patients referred for suspected work-related common mental disorders. To develop a prognostic model.DESIGN: Register-based nationwide longitudinal follow-up study.SETTING: All departments of occupational medicine in Denmark.PARTICIPANTS: 17 822 patients aged 18-67 years, seen for the first time at a Department of Occupational Medicine in Denmark from 2000 to 2013 and diagnosed with stress, depression, post-traumatic stress disorder, anxiety or other mental disorders.INTERVENTIONS: All patients were seen for diagnostic assessment and causal evaluation of the work-relatedness of their disorders. Some departments offered patients with stress disorders psychological treatment, which, however, was not organised according to patient selection or type of treatment.PRIMARY AND SECONDARY OUTCOME MEASURES: Register data were collected for 5 year periods before and after the patients' first assessment at a department. Weekly percentages of patients are presented according to work status. The outcome in the prognostic model was a high Work Participation Score (ie, working&gt;75% of potential work weeks/year) at 5 year follow-up.RESULTS: For all subgroups of patients, a high proportion were working (&gt;75%) 1-5 years before assessment, and all experienced a large reduction in work status at time of assessment. At 1 year follow-up, almost 60% of patients with stress were working, whereas in the other patient subgroups, less than 40% were working. In the following years, practically no increase was observed in the percentage of patients working in any of the subgroups. Based on these 5 year follow-up data, we developed a work participation model with only moderate discrimination and calibration.CONCLUSIONS: In Denmark, not all return to previous work status 5 years after a referral due to a suspected work-related common mental disorder. We developed a prognostic model with only moderate discrimination and calibration for long-term work participation after suggested work-related common mental disorders.</p

Unfolding principles for student peer feedback:A comparative analysis across higher education contexts

In this paper we conceptualize formative peer feedback principles by analyzing and comparing six empirical examples of formative peer feedback in a set of international STEM (science, technology, engineering, and mathematics) contexts. By discussing how these different approaches to peer feedback unfold in practice, we aim to facilitate the bridging of the gap between theory and practice in implementing peer feedback in Higher Education. As a group of researchers and teaching practitioners from six Higher Education institutions, we discussed, analyzed, and synthesized practical examples of peer feedback in STEM that cover a breadth of settings, aims, and forms. The analysis and comparison of these examples illustrate how principles in peer feedback emerge in practice. We discuss how the context in peer feedback influences its practical implementation, particularly with regard to its purpose and aims, the development and use of assessment criteria, and embedding and supporting the initiatives into the teaching and learning activities.peerReviewe