| 1. |
- Callaghan, Terry, et al.
(författare)
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Multi-Decadal Changes in Tundra Environments and Ecosystems : Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF)
- 2011
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40:6, s. 705-716
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the responses of tundra systemsto global change has global implications. Most tundraregions lack sustained environmental monitoring and oneof the only ways to document multi-decadal change is toresample historic research sites. The International PolarYear (IPY) provided a unique opportunity for such researchthrough the Back to the Future (BTF) project (IPY project#512). This article synthesizes the results from 13 paperswithin this Ambio Special Issue. Abiotic changes includeglacial recession in the Altai Mountains, Russia; increasedsnow depth and hardness, permafrost warming, andincreased growing season length in sub-arctic Sweden;drying of ponds in Greenland; increased nutrient availabilityin Alaskan tundra ponds, and warming at mostlocations studied. Biotic changes ranged from relativelyminor plant community change at two sites in Greenland tomoderate change in the Yukon, and to dramatic increasesin shrub and tree density on Herschel Island, and in subarcticSweden. The population of geese tripled at one sitein northeast Greenland where biomass in non-grazed plotsdoubled. A model parameterized using results from a BTFstudy forecasts substantial declines in all snowbeds andincreases in shrub tundra on Niwot Ridge, Colorado overthe next century. In general, results support and provideimproved capacities for validating experimental manipulation,remote sensing, and modeling studies.
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| 2. |
- Jönsson, K. Ingemar, et al.
(författare)
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Tolerance to X-rays and Heavy Ions (Fe, He) in the Tardigrade Richtersius coronifer and the Bdelloid Rotifer Mniobia russeola
- 2017
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Ingår i: Astrobiology. - : Mary Ann Liebert Inc. - 1531-1074 .- 1557-8070. ; 17:2, s. 163-167
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to analyze tolerance to heavy ions in desiccated animals of the eutardigrade Richtersius coronifer and the bdelloid rotifer Mniobia russeola within the STARLIFE project. Both species were exposed to iron (Fe) and helium (He) ions at the Heavy Ion Medical Accelerator in Chiba (HIMAC) in Chiba, Japan, and to X-rays at the German Aerospace Center (DLR) in Cologne, Germany. Results show no effect of Fe and He on viability up to 7 days post-rehydration in both R. coronifer and M. russeola, while X-rays tended to reduce viability in R. coronifer at the highest doses. Mean egg production rate tended to decline with higher doses in R. coronifer for all radiation types, but the pattern was not statistically confirmed. In M. russeola, there was no such tendency for a dose response in egg production rate. These results confirm the previously reported high tolerance to high linear energy transfer (LET) radiation in tardigrades and show for the first time that bdelloid rotifers are also very tolerant to high-LET radiation. These animal phyla represent the most desiccation-and radiation-tolerant animals on Earth and provide excellent eukaryotic models for astrobiological research.
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| 3. |
- Nilsson, E. J. C., et al.
(författare)
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Evaluation of cryoanalysis as a tool for analyzing elemental distribution in live tardigrades using micro-PIXE
- 2014
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 332, s. 181-186
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Tidskriftsartikel (refereegranskat)abstract
- Although heavy on labor and equipment, thus not often applied, cryoanalysis of frozen hydrated biological specimens can provide information that better reflects the living state of the organism, compared with analysis in the freeze-dried state. In this paper we report a study where the cryoanalysis facility with cryosectioning capabilities at Materials Research Department, iThemba LABS, South Africa was employed to evaluate the usefulness of combining three ion beam analytical methods (mu PIXE, RBS and STIM) to analyze a biological target where a better elemental compositional description is needed - the tardigrade. Imaging as well as quantification results are of interest. In a previous study, the element composition and redistribution of elements in the desiccated and active states of two tardigrade species was investigated. This study included analysis of both whole and sectioned tardigrades, and the aim was to analyze each specimen twice; first frozen hydrated and later freeze-dried. The combination of the three analytical techniques proved useful: elements from C to Rb in the tardigrades could be determined and certain differences in distribution of elements between the frozen hydrated and the freeze-dried states were observed. RBS on frozen hydrated specimens provided knowledge of matrix elements.
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| 4. |
- Airey, John, 1963-, et al.
(författare)
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Unpacking the Hertzsprung-Russell Diagram : A Social Semiotic Analysis of the Disciplinary and Pedagogical Affordances of a Central Resource in Astronomy
- 2019
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Ingår i: Designs for Learning. - Stockholm : Stockholm University Press. - 1654-7608 .- 2001-7480. ; 11:1, s. 99-107
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we are interested in the relationship between disciplinary knowledge and its representation. We carry out a social semiotic analysis of a central tool used in astronomy—the Hertzsprung-Russell (H-R) diagram—in order to highlight its disciplinary and pedagogical affordances. The H-R diagram that we know today combines many layers of astronomical knowledge, whilst still retaining some rather quirky traces of its historical roots. Our analysis shows how these ‘layers of knowledge’ and ‘historical anomalies’ have resulted in a number of counterintuitive aspects within the diagram that have successively lowered its pedagogical affordance. We claim that these counterintuitive aspects give rise to potential barriers to student disciplinary learning. Using our analysis as a case study, we generalise our findings, suggesting four types of barrier to understanding that are potentially at work when students meet disciplinary-specific semiotic resources for the first time. We finish the paper by making some general suggestions about the wider use of our analysis method and ways of dealing with any barriers to learning identified. In the specific case of the H-R diagram, we suggest that lecturers should explicitly tease out its disciplinary affordances by the use of ‘unpacked’ resources that have a higher pedagogical affordance.
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| 5. |
- Eriksson, Urban
(författare)
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The Spiral of Teaching and Learning in Physics and Astronomy
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- When students start to learn physics and astronomy, they immediately are confronted with a multitude of representations packed with disciplinary information. This information is embedded in these representations and the students need to learn to discern the relevant information. This is not straightforward, and requires a lot of teaching and practice before being mastered. It carries many similarities to learning a new language – the language of physics, astronomy, or other sciences. However, it all starts with disciplinary discernment from those representations, something that has been shown to be challenging for students. Often the teacher who knows the representations and their appresented meaning—their disciplinary affordances—assumes that the students discern the same things in those representations as the teacher does. Research has shown that this is not the case and such assumptions leads to educational problems for the students and make learning physics or astronomy unnecessary difficult, or even inaccessible to the students. The students need be given the opportunity to develop their competency in discerning disciplinary-specific relevant aspects from representations; a competency referred to as Reading the Sky in an astronomy context, and described by the Anatomy of Disciplinary Discernment (Eriksson, 2014a; Eriksson et al., 2014b). Furthermore, physics and astronomy are subjects aiming to describe the real multidimensional world, hence involve a substantial amount of spatial thinking. The students need to learn to extrapolate three-dimensionality in their minds from two-dimensional representations, which have been shown to be challenging to students. Unfortunately, this competency is often taken for granted and rarely addressed in teaching (Eriksson et al., 2014c). In this talk we present a model in which we identify and describe the critical competencies needed to “read” disciplinary-specific representations; it concerns not only disciplinary discernment but also spatial thinking and disciplinary knowledge. These are combined into the Spiral of Teaching and Learning (STL), a new and powerful model for optimizing teaching and learning science (Eriksson, 2014a; Eriksson, 2015). We discuss consequences and possibilities when applying the STL model and give an example of how this model can be used in teaching and learning astronomy.
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| 6. |
- Linder, Cedric, et al.
(författare)
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The overlooked challenge of learning to extrapolate three-dimensionality
- 2013
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Ingår i: Book of Abstracts. - : Charles University.
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Konferensbidrag (refereegranskat)abstract
- Learning astronomy has many learning challenges due to the highly diverse, conceptual, and theoretical thinking used in the discipline. One taken for granted challenge is the learning to extrapolate three-dimensionality. Although we have the ability to see our surroundings in threedimensional terms, beyond a distance of about 200m this ability quickly becomes very limited. So, when looking up at the night sky, learning to discern critical features that are embedded in dimensionality does not come easily. There have been several articles addressing how fruitful 3D simulations are for astronomy education, but they do not address what students discern, nor the nature of that discernment. Taking the concept of discernment to be about noticing something and assigning meaning to it, our research question is: In terms of dimensionality, what do astronomy/physics students and professors discern when engaging with a simulated video flythrough of our Galaxy and beyond?A web-based questionnaire was designed using links to video clips drawn from a well-regarded simulation-video of travel through our galaxy and beyond. 137 physics and astronomy university students and teaching professors, who were drawn from nine countries, completed the questionnaire. The descriptions provided by them were used to formulate six categories of discernment in relation to multidimensionality. These results are used to make the case that astronomy learning that aims at developing the ability to extrapolate three-dimensionality needs to be grounded in the creation of meaningful motion parallax experiences. Teaching and learning implications are discussed.
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| 7. |
- Eriksson, Urban, et al.
(författare)
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Who needs 3D when the Universe is flat?
- 2014
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Ingår i: Science Education. - : Wiley. - 0036-8326 .- 1098-237X. ; 98:3, s. 412-442
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Tidskriftsartikel (refereegranskat)abstract
- An overlooked feature in astronomy education is the need for students to learn to extrapolate three-dimensionality and the challenges that this may involve. Discerning critical features in the night sky that are embedded in dimensionality is a long-term learning process. Several articles have addressed the usefulness of three-dimensional (3D) simulations in astronomy education, but they have neither addressed what students discern nor the nature of that discernment. A Web-based questionnaire was designed using links to video clips drawn from a simulation video of travel through our galaxy and beyond. The questionnaire was completed by 137 participants from nine countries across a broad span of astronomy education. The descriptions provided by the participants were analyzed using hermeneutics in combination with a constant comparative approach to formulate six categories of discernment in relation to multidimensionality. These results are used to make the case that the ability to extrapolate three-dimensionality calls for the creation of meaningful motion parallax experiences.
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| 8. |
- Hansson, Lena, et al.
(författare)
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Att utgå från frågor och situationer i förskolans vardag : vilket naturvetenskapligt innehåll kan det leda till?
- 2014
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Ingår i: NorDiNaNordic Studies in Science Education. - 1504-4556. ; 10:1, s. 77-89
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Tidskriftsartikel (refereegranskat)abstract
- Identifying and building on children’s questions and everyday situations is often discussed as a basis for science learning in preschool. With a starting point in such questions and situations, children should be given the opportunity to investigate and search for answers. What questions and situations do preschool teachers identify as possible bases for science learning? What science content is present? To what extent are the questions possible to investigate for children and preschool teachers through experiments and observations or theoretical studies? The paper presents children’s questions and everyday situations that might form the basis for science learning, as identified by preschool teachers taking part in a science in-service training course. Based on a content analysis, we discuss possibilities and difficulties that preschool teachers may face in their practice when they try to use these questions and situations as a basis for science learning.
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| 9. |
- Hansson, Lena, et al.
(författare)
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Working with the nature of science in physics class : Turning 'ordinary' classroom situations into nature of science learning situations
- 2016
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Ingår i: Physics Education. - : IOP Publishing. - 0031-9120 .- 1361-6552. ; 51:5
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Tidskriftsartikel (refereegranskat)abstract
- In the science education research field there is a large body of literature on the 'nature of science' (NOS). NOS captures issues about what characterizes the research process as well as the scientific knowledge. Here we, in line with a broad body of literature, use a wide definition of NOS including also e.g. socio-cultural aspects. It is argued that NOS issues, for a number of reasons, should be included in the teaching of science/physics. Research shows that NOS should be taught explicitly. There are plenty of suggestions on specific and separate NOS activities, but the necessity of discussing NOS issues in connection to specific science/physics content and to laboratory work, is also highlighted. In this article we draw on this body of literature on NOS and science teaching, and discuss how classroom situations in secondary physics classes could be turned into NOS-learning situations. The discussed situations have been suggested by secondary teachers, during in-service teacher training, as situations from every-day physics teaching, from which NOS could be highlighted.
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| 10. |
- Pendrill, Ann-Marie, et al.
(författare)
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Motion on an inclined plane and the nature of science
- 2014
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Ingår i: Physics Education. - : IOP Publishing Ltd.. - 0031-9120 .- 1361-6552. ; 49:2, s. 180-186
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Tidskriftsartikel (refereegranskat)abstract
- Friction is an important phenomenon in everyday life. All children are familiar with playground slides, which may thus be a good starting point for investigating friction. Motion on an inclined plane is a standard physics example. This paper presents an investigation of friction by a group of 11-yearolds. How did they plan their investigations? What aspects of friction could they discern? What understanding of the nature of science was revealed—and developed—during their investigation and subsequent discussion with the teacher?
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