Changes in species richness and composition of boreal waterbird communities : a comparison between two time periods 25 years apart

Global measures of biodiversity indicate consistent decline, but trends reported for local communities are more varied. Therefore, we need better understanding of mechanisms that drive changes in diversity of local communities and of differences in temporal trends between components of local diversity, such as species richness and species turnover rate. Freshwater ecosystems are vulnerable to multiple stressors, and severe impacts on their biodiversity have been documented. We studied species richness and composition of local boreal waterbird communities in 1990/1991 and 2016 at 58 lakes distributed over six regions in Finland and Sweden. The study lakes represented not only local trophic gradients but also a latitudinal gradient in the boreal biome. While species richness tended to be lower in 2016 than in 1990/1991, species turnover was relatively high. Within foraging guilds, local species richness of diving ducks and surface feeding waterbirds decreased, whereas that of large herbivores increased. The number of species gained in local communities was higher in lakes with rich vegetation than in lakes with sparse vegetation. Conservation of boreal freshwater ecosystems would benefit from recognizing that large-scale environmental changes can affect local diversity via processes operating at finer scales.Peer reviewe

Recovering Whooper Swans do not cause a decline in Eurasian Wigeon via their grazing impact on habitat

Zusammenfassung: Wiedererstarken der Singschwäne-Populationen verursacht durch das Grasen im gleichen Habitat keinen Rückgang der PfeifenteThe Whooper Swan (Cygnus cygnus) is a good example of successful conservation, with rapidly growing numbers in Fennoscandia in recent decades. To the contrary, Eurasian Wigeon (Mareca penelope) shows a strong negative trend in breeding numbers, which raises conservation concerns. Previous research suggests a causal link between recent population trajectories of the two species. Both preferentially breed on wetlands with abundant horsetail (Equisetum spp.), a plant providing food for Whooper Swan and crucial feeding microhabitat for Eurasian Wigeon broods. We here test predictions based on the hypothesis that grazing on Equisetum by Whooper Swan reduces breeding habitat or breeding habitat quality for Eurasian Wigeon. We use data from 60 lakes in which waterfowl were counted in 1990-1991 and 2016, and Equisetum was mapped in 1990-1991 and 2013-2014. Lakes colonized by Whooper Swan typically had more abundant Equisetum vegetation in the past than lakes not colonized. Lake-specific decrease of Equisetum was not associated with colonization by Whooper Swan. The number of lakes occupied by Eurasian Wigeon decreased, but the decrease was not stronger on lakes colonized by Whooper Swan than on those that were not. Contrary to our prediction, current Eurasian Wigeon abundance was positively associated with Whooper Swan abundance. Moreover, Eurasian Wigeon did not decrease more on lakes from which Equisetum disappeared than on lakes in which there was still Equisetum left. This study does not support the idea that Whooper Swan affects Eurasian Wigeon negatively by grazing on Equisetum.Peer reviewe

Bacteria Penetrate the Inner Mucus Layer before Inflammation in the Dextran Sulfate Colitis Model

Protection of the large intestine with its enormous amount of commensal bacteria is a challenge that became easier to understand when we recently could describe that colon has an inner attached mucus layer devoid of bacteria (Johansson et al. (2008) Proc. Natl. Acad. Sci. USA 105, 15064-15069). The bacteria are thus kept at a distance from the epithelial cells and lack of this layer, as in Muc2-null mice, allow bacteria to contact the epithelium. This causes colitis and later on colon cancer, similar to the human disease Ulcerative Colitis, a disease that still lacks a pathogenetic explanation. Dextran Sulfate (DSS) in the drinking water is the most widely used animal model for experimental colitis. In this model, the inflammation is observed after 3-5 days, but early events explaining why DSS causes this has not been described.When mucus formed on top of colon explant cultures were exposed to 3% DSS, the thickness of the inner mucus layer decreased and became permeable to 2 microm fluorescent beads after 15 min. Both DSS and Dextran readily penetrated the mucus, but Dextran had no effect on thickness or permeability. When DSS was given in the drinking water to mice and the colon was stained for bacteria and the Muc2 mucin, bacteria were shown to penetrate the inner mucus layer and reach the epithelial cells already within 12 hours, long before any infiltration of inflammatory cells.DSS thus causes quick alterations in the inner colon mucus layer that makes it permeable to bacteria. The bacteria that reach the epithelial cells probably trigger an inflammatory reaction. These observations suggest that altered properties or lack of the inner colon mucus layer may be an initial event in the development of colitis

Om det inte är dyskalkyli - vad är det då? : En multimetodstudie av eleven i matematikproblem ur ett longitudinellt perspektiv

One of the big problems of the Swedish nine-year compulsory school is the large number of pupils who fail to achieve a satisfactory standard in mathematics. One explanation that has been increasingly considered over the last ten years is that the pupils have dyscalculia. Some research suggests that 6 per cent of compulsory school pupils suffer from this dysfunction, which would in that case make it one of the Swedish school’s greatest teaching problems. The purpose of this thesis is to examine this problem area from two aspects. First of all by examining the concept of dyscalculia by means of a review of the literature from 1992 onwards. The second perspective has as its starting point a case study where the purpose was to give a detailed picture of the pupil with mathematics problems. The latter part of the study was carried out over a six-year period when 200 pupils, 13 of them with particular mathematics problems, were studied in detail. A point of departure for the study was provided by a large database where as much information as possible was collected about pupils from Year 5 of the nine-year compulsory school to Year 2 of the three-year upper secondary school. The pupils were asked to fill in regular questionnaires and classroom observations were made of roughly 100 mathematics lessons, 40 of which were recorded on video. Finally there were in-depth interviews of the 13 pupils on two occasions, the final one being during Year 2 of the upper secondary school. The review of the research showed a series of dubious and indistinct circumstances surrounding the dyscalculia concept, and also ambiguity with regard to the diagnosis of dyscalculia. The conclusion of the review was that the concept of dyscalculia ought at present to be used with great caution, or perhaps not at all. Admittedly the review does not provide grounds for totally dismissing the dyscalculia concept, but as long as it remains impossible to determine the concept unambiguously, and I have not been able to do this in the course of this study, there are no good scientific grounds for using the term dyscalculia in practice. The empirical study shows the complexity of the problem area. Both the causes suggested by the pupils as the origin of the problem and the measures that helped them to obtain their mathematics grades form a complex pattern. The low work input of the pupils during mathematics lessons, an unsettled working environment, large classes, problems of stress and anxiety prior to tests, and obstructive gender patterns are among the causes suggested by the pupils as explanations of the occurrence of the mathematics problems. Good teachers, in other words teachers who can explain, set limits and give encouragement, were a significant factor in reversing the downward trend. Positive experiences of school changes, where the pupil felt that he or she could start again from the beginning, were also mentioned as significant by several pupils. Collaboration with fellow-pupils and the fact that the pupils themselves decided to get to grips with the problems were other important reasons for the change. The prospects of students with specific problems in mathematics nevertheless being able to leave compulsory school with satisfactory grades appear, however, from the results of this study, to be bright. All the pupils left the compulsory school with satisfactory mathematics grades and also completed mathematics studies at upper secondary school, despite major problems in the subject at intermediate school (age 10-13) stage. The study indicates the need for research closer to the actual practical situation and to the importance of emphasizing good examples in practice. As the students themselves emphasize discrete communication between them as significant in the subject of mathematics, this is also an important area for future research

Nestin : filament formation and expression in myogenesis and muscle disorders

NESTIN: FILAMENT FORMATION AND EXPRESSION IN MYOGENESIS ANDMUSCLE DISORDERS Gunnar Sjöberg Department of Cell and Molecular Biology, Karolinska InstitutetStockholm Intermediate filaments (IF), together with microfilaments and microtubules, arethe major components of the cytoskeleton of eukaryotic cells. In myogenic cells threeIF proteins are expressed; desmin, vimentin and nestin. The present investigationanalyzes filament assembly and expression of these IFs in myogenesis and musculardisorders, with special focus on the IF protein nestin. Nestin was shown to colocalize with desmin and vimentin throughout the cytoplasmof human fetal myoblasts and myotubes. This indicated a co-assembly of nestin withthe other IFs, and when a full length nestin construct was transfected into an IF-freecell line, nestin was unable to form filaments by itself. However, in occasionalcells expressing vimentin, and in cells previously transfected with a desmun construct,nestin is included in the respective IF network. In a yeast two-hybrid system, whereprotein-protein interactions are analyzed, nestin interacted strongly with vimentinand desmin, but weakly with itself. The inability of nestin to form homopolymersis therefore most likely due to an inability to form homodimers. Nestin has been shown to have a transient expression pattern in skeletal muscle development.To further characterize nestin expression in developing muscle, we analyzed limbbud and heart at different stages of development. In the developing limb bud of mice,nestin expression was detected early, at low levels, in undifferentiated mesenchymalcells, but as differentiation proceeded, nestin was upregulated in cells undergoingmyogenesis and downregulated in cells undergoing chondrogenesis. Nestin expressioncould be modified by the addition of growth factors affecting myogenic differentiation.A differential localization of nestin mRNA and protein was seen, where the mRNA waslocalized to the ends of the myofibers, while the protein was more uniformly distnbuted.In the developing heart, nestin expression was found in the atria and in a subsetof cells, with a subendocardiac location, in the ventricles. In the adult heart nestinis confined to a small population of cells, the type of which needs further characterlzatlon. Certain pathological disorders are known to be associated with a reexpression ofdevelopmentally downregulated proteins. This has shown to be useful in the pathologicaldiagnosis of these disorders. Nestin, having a tissue restricted and developmentallyregulated expression pattern, was analysed for expression in regenerative muscledisorders and rhabdomyosarcomas (RMS). In material from patients with muscular dystrophiesor myositis, nestin was detected in regenerating muscle fibers. In RMS, nestin wasshown to be expressed in all RMS also expressing desmin. In addition, one tumor,presumably a RMS, showed nestin, but not desmin expression, indicating that nestinmay be a more sensitive marker for RMS than desmin. Finally, nestin expression ina case of desminopathy was found and compared to expression of desmin and vimentin. In conclusion, nestin has been shown to be an obligate heterodimer in filament formation,and vimentin or desmin are the dimerizing partners in muscle cells. In the developingembryo nestin expression is restricted to certain tissues in a developmentally regulatedprogram. We have also shown that the reappearance of nestin expression can be ofpotential use in histopathological diagnosis of certain neuromuscular disorders . Keywords: Intermediate filament, nestin, desmin, vimentin, myogenesis neuromusculardisorders, rhabdomyosarcoma ISBN 91-628-2687-

Vädrets inverkan på föroreningshalter och depositioner i bakgrundsluft i Sverige.

Mätdata för EMEP-nätet har utvärderats för att visa vädrets påverkan på haltnivåer och depositioner. Studien har gjorts av hur transportriktningen inverkar på halter i luft och nederbörd, och hur nederbördsmängden inverkar på halter i nederbörden och på deponerade mängden av föroreningar. Vidare beskrivs vädersituation vintertid och sommartid som ger upphov till föroreningstransport och föroreningsbelastning i Skandinavien.Mätdata för EMEP-nätet har utvärderats för att visa vädrets påverkan på haltnivåer och depositioner. Studien har gjorts av hur transportriktningen inverkar på halter i luft och nederbörd, och hur nederbördsmängden inverkar på halter i nederbörden och på deponerade mängden av föroreningar. Vidare beskrivs vädersituation vintertid och sommartid som ger upphov till föroreningstransport och föroreningsbelastning i Skandinavien

Disciplined by tests

This article reports on a Swedish research project on the reintroduction of national tests in mathematics for nine- to ten-year-old pupils. Data were collected over a period of three years (2010-2012) by video recording test situations in different classrooms and by conducting video-stimulated recall interviews with children. The aim is to explore and analyse the testing situation and how it creates different positions for children. We conclude that discourses of testing, caring and competition, sometimes strengthening and sometimes shadowing each other and thereby, produce knowledge in children about success and failure in mathematics, positioning children as ‘winners’ or ‘losers’. The tests are interpreted as a technology – a form of disciplinary power that functions at the level of the body (Foucault, 1980).Vad gör testandet med eleven? En studie kring nationella prov i matemati

Disciplined by tests

This article reports on a Swedish research project on the reintroduction of national tests in mathematics for nine- to ten-year-old pupils. Data were collected over a period of three years (2010-2012) by video recording test situations in different classrooms and by conducting video-stimulated recall interviews with children. The aim is to explore and analyse the testing situation and how it creates different positions for children. We conclude that discourses of testing, caring and competition, sometimes strengthening and sometimes shadowing each other and thereby, produce knowledge in children about success and failure in mathematics, positioning children as ‘winners’ or ‘losers’. The tests are interpreted as a technology – a form of disciplinary power that functions at the level of the body (Foucault, 1980).Vad gör testandet med eleven? En studie kring nationella prov i matemati

Disciplined by tests

This article reports on a Swedish research project on the reintroduction of national tests in mathematics for nine- to ten-year-old pupils. Data were collected over a period of three years (2010-2012) by video recording test situations in different classrooms and by conducting video-stimulated recall interviews with children. The aim is to explore and analyse the testing situation and how it creates different positions for children. We conclude that discourses of testing, caring and competition, sometimes strengthening and sometimes shadowing each other and thereby, produce knowledge in children about success and failure in mathematics, positioning children as ‘winners’ or ‘losers’. The tests are interpreted as a technology – a form of disciplinary power that functions at the level of the body (Foucault, 1980).Vad gör testandet med eleven? En studie kring nationella prov i matemati