| 1. |
- Moles, Angela T, et al.
(författare)
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Correlations between physical and chemical defences in plants : tradeoffs, syndromes, or just many different ways to skin a herbivorous cat?
- 2013
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Ingår i: New Phytologist. - : Wiley-Blackwell. - 0028-646X .- 1469-8137. ; 198:1, s. 252-263
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Tidskriftsartikel (refereegranskat)abstract
- Most plant species have a range of traits that deter herbivores. However, understanding of how different defences are related to one another is surprisingly weak. Many authors argue that defence traits trade off against one another, while others argue that they form coordinated defence syndromes. We collected a dataset of unprecedented taxonomic and geographic scope (261 species spanning 80 families, from 75 sites across the globe) to investigate relationships among four chemical and six physical defences. Five of the 45 pairwise correlations between defence traits were significant and three of these were tradeoffs. The relationship between species' overall chemical and physical defence levels was marginally nonsignificant (P=0.08), and remained nonsignificant after accounting for phylogeny, growth form and abundance. Neither categorical principal component analysis (PCA) nor hierarchical cluster analysis supported the idea that species displayed defence syndromes. Our results do not support arguments for tradeoffs or for coordinated defence syndromes. Rather, plants display a range of combinations of defence traits. We suggest this lack of consistent defence syndromes may be adaptive, resulting from selective pressure to deploy a different combination of defences to coexisting species.
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| 3. |
- Jaldemark, Jimmy, Docent, 1970-, et al.
(författare)
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Wearable technologies as a research tool for studying learning : The application of spy glasses in data collection of children's learning
- 2019. - 2
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Ingår i: Handbook of mobile teaching and learning. - : Springer. - 9789811327650
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Bokkapitel (refereegranskat)abstract
- This chapter discusses the potential that wearable technologies have for studying and understanding how people learn. In particular, the focus is on how spy glasses can be used as a tool for collecting data from educational situations. The chapter report from two different cases performed by the authors in which spy glasses were used, including considerations made from a methodological point of view. From the first case a conclusion is that spy-glass recording made it possible to closely follow teaching and learning during science labwork and find specific elements not found in video data from ordinary video cameras. The second case reports on valuable information about how the motivation for learning works in young children. Drawing further from these studies, the study elaborate on themes that arise as central to video research: ethics, technology and methodology as well as selection and analysis. The chapter discusses a transformation in how childhood is considered in relation to new technology. Here children are seen as more active and participatory in the shaping of their own childhoods. This can also result in developing new research methods in order to understand and visualise the child’s perspective, and using wearable technologies could certainly be one of these areas. In other words, it is a unique perspective when participants are co-creators of research studies. This implies important future work ahead, developing and applying wearable technologies for education and educational research.
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| 4. |
- Johansson, Helena, 1971-, et al.
(författare)
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Engineering students’ approach to studying mathematics and its influence on their achievement
- 2021
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Konferensbidrag (refereegranskat)abstract
- Previous research has addressed undergraduate students’ approaches to studying mathematics from various perspective, with differing results regarding influences on achievements. This study contributes to the fields understanding by examine if and how engineering students’ various approaches to studying mathematics, particularly a differential calculus course, affect their success on the course exam. Three questionnaires were distributed to the students and a logistic regression model showed that the habit to study regularly had a positive effect on exam results, whereas the strategy to imitate previous examples had a negative effect.
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| 5. |
- Moles, A. T., et al.
(författare)
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Putting plant resistance traits on the map : A test of the idea that plants are better defended at lower latitudes
- 2011
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 191:3, s. 777-788
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Tidskriftsartikel (refereegranskat)abstract
- It has long been believed that plant species from the tropics have higher levels of traits associated with resistance to herbivores than do species from higher latitudes. A meta-analysis recently showed that the published literature does not support this theory. However, the idea has never been tested using data gathered with consistent methods from a wide range of latitudes. • We quantified the relationship between latitude and a broad range of chemical and physical traits across 301 species from 75 sites world-wide. • Six putative resistance traits, including tannins, the concentration of lipids (an indicator of oils, waxes and resins), and leaf toughness were greater in high-latitude species. Six traits, including cyanide production and the presence of spines, were unrelated to latitude. Only ash content (an indicator of inorganic substances such as calcium oxalates and phytoliths) and the properties of species with delayed greening were higher in the tropics. • Our results do not support the hypothesis that tropical plants have higher levels of resistance traits than do plants from higher latitudes. If anything, plants have higher resistance toward the poles. The greater resistance traits of high-latitude species might be explained by the greater cost of losing a given amount of leaf tissue in low-productivity environments. © 2011 New Phytologist Trust.
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| 6. |
- Sandström, Jennie
(författare)
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Phytoplankton response to a changing climate in lakes in northern Sweden
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a climate change perspective, increased air temperatures are already a reality and are expected to increase even more in the future, especially in areas at high latitudes. The present thesis therefore addresses the influence of climate change on the physical properties and the phytoplankton communities of typical small and oligotrophic lakes in northern Sweden (62-64˚N). In the first part of the study, we found a significant trend (10 lakes from 1916 to 2010) of ice break-ups occurring increasingly earlier. The timing of ice break-up was strongly influenced by the April air temperature indicating that expected increases in air temperature in the future will also result in an earlier ice break-up. We also used concentrations of chlorophyll a (chl a) as estimations of phytoplankton biomass and discovered a positive relationship between surface water temperature and concentrations of chl a in Lake Remmaren (from 1991 to 2008). The second part of the thesis focuses on climatic conditions and cyanobacteria abundance in three small, oligotrophic lakes in northern Sweden; Lake Remmaren, Lake S. Bergsjön and Lake Gransjön. The concentration and relative abundance of cyanobacteria differ between 2011 and 2012, with different climatic conditions. The "warm" year of 2011 had higher concentrations and relative abundance of cyanobacteria than the "cold" year of 2012. Trends in increasing surface water temperatures as well as increasing abundance of cyanobacteria in August were found in Lake Remmaren (from 1988 to 2011). The direct or indirect effects of warming had a positive effect on the cyanobacteria abundance, since nutrients (Tot N and Tot P) did not display an increasing trend in Lake Remmaren. An analysis on the composition of phytoplankton species in Lake Remmaren, Lake S. Bergsjön and Lake Gransjön revealed that the cyanobacteria Merismopedia sp. was more common in 2011 than 2012. If different cyanobacteria become more common in oligotrophic lakes in the future, the functioning of lake ecosystems may be impacted. Small zooplankton eats small phytoplankton and if smaller phytoplankton species, e.g. cyanobacteria, increase at the expense of other phytoplankton groups, an extra step in the food chain might be added. Less energy might be transferred to the upper levels because many cyanobacteria contain toxic compounds and are less edible than other phytoplankton groups. An increase of toxic containing cyanobacteria in lakes can also make lakes less attractive for recreational purposes in the future.
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| 9. |
- von Zeipel, Hugo, et al.
(författare)
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Fruit removal in the forest herb Actaea spicata depends on local context of fruits sharing the same dispersers
- 2007
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Ingår i: International journal of plant sciences. - : University of Chicago Press. - 1058-5893 .- 1537-5315. ; 168:6, s. 855-860
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Tidskriftsartikel (refereegranskat)abstract
- Heterospecific effects from neighboring plants on fruit removal are rarely examined. In this study we recorded removal of fruits of four species from experimental plots. The main study species, the forest herb Actaea spicata, has berries attractive to rodents. We tested for effects from a larger-scale context (plant abundance) and a smaller scale (number of fruits aggregated including several species with fleshy as well as dry fruits). Fruit removal varied among sites. Fleshy-fruited species removal was correlated within sites. Fruit removal was higher within than outside Actaea populations but was unrelated to plant abundances among existing populations. The small-scale context treatment yielded clear results. Removal of Actaea fruits was higher from large aggregations of fruits, and it was the number of fruits rather than species identity that affected removal. Presence of both fleshy and dry fruits increased removal. This study provides experimental evidence of heterospecific effects on fruit removal, and we conclude that the species included in the study attract the same dispersers and that the small-scale biotic context is important. We suggest the existence of dispersal hot spots related to the fruit presence overlaid by an unexplained variation among sites.
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