| 1. |
- Edger, Patrick P., et al.
(författare)
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The butterfly plant arms-race escalated by gene and genome duplications
- 2015
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:27, s. 8362-8366
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Tidskriftsartikel (refereegranskat)abstract
- Coevolutionary interactions are thought to have spurred the evolution of key innovations and driven the diversification of much of life on Earth. However, the genetic and evolutionary basis of the innovations that facilitate such interactions remains poorly understood. We examined the coevolutionary interactions between plants (Brassicales) and butterflies (Pieridae), and uncovered evidence for an escalating evolutionary arms-race. Although gradual changes in trait complexity appear to have been facilitated by allelic turnover, key innovations are associated with gene and genome duplications. Furthermore, we show that the origins of both chemical defenses and of molecular counter adaptations were associated with shifts in diversification rates during the arms-race. These findings provide an important connection between the origins of biodiversity, coevolution, and the role of gene and genome duplications as a substrate for novel traits.
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| 2. |
- Betson, N. R., et al.
(författare)
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No diurnal variation in rate or carbon isotope composition of soil respiration in a boreal forest
- 2007
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Ingår i: Tree Physiology. - 0829-318X. ; 27:5, s. 749-756
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Tidskriftsartikel (refereegranskat)abstract
- Characterization of soil respiration rates and delta(13C) values of soil-respired CO2 are often based on measurements at a particular time of day. A study by Gower et al. (2001) in a boreal forest demonstrated diurnal patterns of soil CO2 flux using transparent measurement chambers that included the understory vegetation. It is unclear whether these diurnal patterns were solely the result of photosynthetic CO2 uptake during the day by the understory or whether there were underlying trends in soil respiration, perhaps driven by plant root allocation, as recently demonstrated in Mediterranean oak savannah. We undertook intensive sampling campaigns in a boreal Picea abies L. Karst. forest to investigate whether diurnal variations in soil respiration rate and stable carbon isotope ratio (delta C-13) exist in this ecosystem when no understory vegetation is present in the measurement chamber. Soil respiration rates and delta C-13 were measured on plots in which trees were either girdled (to terminate the fraction of soil respiration directly dependent on recent photosynthate from the trees), or not girdled, every 4 h over two 48-hour cycles during the growth season of 2004. Shoot photosynthesis and environmental parameters were measured concurrently. No diurnal patterns in soil respiration rates and delta C-13 were observed in either treatment, despite substantial variations in climatic conditions and shoot photosynthetic rates in non-girdled trees. Consequently, assessment of daily soil respiration rates and delta C-13 in boreal forest systems by single, instantaneous daily measurements does not appear to be confounded by substantial diurnal variation.
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| 3. |
- Bredie, W.L.P., et al.
(författare)
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Methods for artificial perception : Can machine replace man?
- 2006
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Ingår i: Developments in Food Science. - 0167-4501. ; 43:C, s. 617-618
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Tidskriftsartikel (refereegranskat)abstract
- The previous 'Scandinavian' Weurman Flavour Symposium held in Oslo, Norway, in 1987 had as the main themes chemistry, biotechnology, sensory science and data analysis in flavour research [1]. Since then, many advances have been made, however, when comparing with the Weurman Symposium in 2005, the subject areas and topics of research have not changed very much. Flavour scientists still work with identification of aroma and taste components in foods, their formation, stability and release as well as sensory and data analytical aspects. The knowledge about flavour components in foods and the understanding of the way we perceive them has though considerably expanded. Advances have also been made in the way one can analyse flavours in foods and beverages, and measure responses from and in human subjects. One can say that the toolbox with methods and techniques for flavour analysis has expanded remarkably offering many new possibilities to understand flavour from different perspectives and levels of details. The workshop presented some state-of-the-art applications of modern in vivo and in vitro flavour analysis as well as visual sensory assessments of meals made by machines equipped with sensors and artificial networks processing capability. Also, new ways of studying multisensory processes by stimulating sensory subjects with defined stimuli were discussed. Intelligent 'artificial perception' systems may replace some routine sensory analysis and monotonous production tasks in the future, but the development of such systems still require sensory assessments by humans. © 2006 Elsevier B.V. All rights reserved.
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| 4. |
- Cuni-Sanchez, Aida, et al.
(författare)
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High aboveground carbon stock of African tropical montane forests
- 2021
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 596:7873, s. 536-542
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Tidskriftsartikel (refereegranskat)abstract
- Tropical forests store 40–50 per cent of terrestrial vegetation carbon. However, spatial variations in aboveground live tree biomass carbon (AGC) stocks remain poorly understood, in particular in tropical montane forests. Owing to climatic and soil changes with increasing elevation, AGC stocks are lower in tropical montane forests compared with lowland forests. Here we assemble and analyse a dataset of structurally intact old-growth forests (AfriMont) spanning 44 montane sites in 12 African countries. We find that montane sites in the AfriMont plot network have a mean AGC stock of 149.4 megagrams of carbon per hectare (95% confidence interval 137.1–164.2), which is comparable to lowland forests in the African Tropical Rainforest Observation Network4 and about 70 per cent and 32 per cent higher than averages from plot networks in montane and lowland forests in the Neotropics, respectively. Notably, our results are two-thirds higher than the Intergovernmental Panel on Climate Change default values for these forests in Africa8. We find that the low stem density and high abundance of large trees of African lowland forests is mirrored in the montane forests sampled. This carbon store is endangered: we estimate that 0.8 million hectares of old-growth African montane forest have been lost since 2000. We provide country-specific montane forest AGC stock estimates modelled from our plot network to help to guide forest conservation and reforestation interventions. Our findings highlight the need for conserving these biodiverse and carbon-rich ecosystems.
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