| 1. |
- Schrader, J., et al.
(author)
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Cambial meristem dormancy in trees involves extensive remodelling of the transcriptome
- 2004
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In: The Plant Journal. - Malden : Wiley-Blackwell. - 0960-7412 .- 1365-313X. ; 40:2, s. 173-187
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Journal article (peer-reviewed)abstract
- The establishment of the dormant state in meristems involves considerable physiological and metabolic alterations necessary for surviving unfavourable growth conditions. However, a global molecular analysis of dormancy in meristems has been hampered by the difficulty in isolating meristem cells. We used cryosectioning to isolate purified cambial meristem cells from the woody plant Populus tremula during active growth and dormancy. These samples were used to generate meristem-specific cDNA libraries and for cDNA microarray experiments to define the global transcriptional changes underlying cambial dormancy. The results indicate a significant reduction in the complexity of the cambial transcriptome in the dormant state. Although cell division is terminated in the dormant cambium, the cell cycle machinery appears to be maintained in a skeletal state as suggested by the continued presence of transcripts for several cell cycle regulators. The downregulation of PttPIN1 and PttPIN2 transcripts explains the reduced basipetal polar auxin transport during dormancy. The induction of a member of the SINA family of ubiquitin ligases implicated in auxin signalling indicates a potential mechanism for modulation of auxin sensitivity during cambial dormancy. The metabolic alterations during dormancy are mirrored in the induction of genes involved in starch breakdown and the glyoxysomal cycle. Interestingly, the induction of RGA1 like gene suggests modification of gibberellin signalling in cambial dormancy. The induction of genes such as poplar orthologues of FIE and HAP2 indicates a potential role for these global regulators of transcription in orchestrating extensive changes in gene expression during dormancy.
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| 2. |
- Gavrilets, Sergey, et al.
(author)
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The evolution of female mate choice by sexual conflict
- 2001
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In: Proceedings of the Royal Society of London Series B. - London : The Roylal Society. - 0080-4649 .- 0962-8452 .- 1471-2954. ; 268:1466, s. 531-539
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Journal article (peer-reviewed)abstract
- Although empirical evidence has shown that many male traits have evolved via sexual selection by female mate choice, our understanding of the adaptive value of female mating preferences is still very incomplete. It has recently been suggested that female mate choice may result from females evolving resistance rather than attraction to males, but this has been disputed. Here, we develop a quantitative genetic model showing that sexual conflict over mating indeed results in the joint evolution of costly female mate choice and exaggerated male traits under a wide range of circumstances. In contrast to traditional explanations of costly female mate choice, which rely on indirect genetic benefits, our model shows that mate choice can be generated as a side–effect of females evolving to reduce the direct costs of mating.
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| 3. |
- Öhman, Marcus, et al.
(author)
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Reasons for slagging during stemwood pellet combustion and some measures for prevention
- 2004
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In: Biomass and Bioenergy. - Oxford : Pergamon Press. - 0961-9534 .- 1873-2909. ; 27:6, s. 597-605
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Journal article (peer-reviewed)abstract
- Ash related problems have more than occasionally been observed in pellet burners during the last years. These problems lead to reduced accessibility of the appliances and also bad publicity for the pellet market. The objectives of the present work were therefore to: (i) determine the critical levels of the problematic ash components in stemwood pellets regarding slagging, (ii) document the variations of these problematic elements in the outgoing pellets from two pellet-mills during one operational season, (iii) determine how frequently these elements exceed the critical levels, (iv) determine how different sub-processes in the pelletising process (especially the dryer) effect the slagging properties of the pellet, and if possible (v) suggest some measures for prevention. A significant number of wood pellets reported to be problematic and problem-free, regarding slagging in ordinary residential pellet burners, were collected from the Swedish market. The ash compositions of these fuels were analysed and the results compiled in a database. Partial Least-Squares Discriminant Analysis (PLS-DA) and F-tests were used to statistically identify both the critical ash components and the critical levels of these components that separated the two reported classes. In addition, chemical equilibrium model calculations were used to interpret the findings. The variations of these elements in the in-going raw material and in the produced pellets were determined during one season in two pellet mills equipped with exhaust gas dryers. The results showed that the problematic wood-pellets had a significantly higher amount of Si, but also Al and Fe, in the fuel ash. The critical level of Si (given as SiO2) was about 20-25 wt% of the fuel ash, i.e. pellets with levels in or over this range resulted in slagging problems in residential burners. This critical Si content was exceeded once and twice for the analysed samples in the two studied pellet mills. In one of the studied mills, this was because of contamination by sand of the raw material during storage and handling, and in the other mill the reason was found to be contamination of the raw material by elutriated particles from the dryer fuel. The major conclusion of the work is that both raw materials and drying fuels/processes should be carefully treated to avoid mineral contamination, and an additional cyclone separator could potentially also be used to improve the pellet quality.
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| 4. |
- Wolf, Annett, et al.
(author)
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Storm damage and long-term mortality in a semi-natural, temperate deciduous forest
- 2004
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In: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 188:1-3, s. 197-210
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Journal article (peer-reviewed)abstract
- 1.Wind-damaged trees, following the severe storm of 1999, are compared with data from a 50-year monitoring of Draved Forest, Denmark, to assess differing causes of mortality through time in an unmanaged semi-natural forest. Species-specific mortality characteristics and the changing effects of tree size and growth rate (diameter increment) on mortality through time are also investigated.2.Storm was found to be the major mortality factor affecting large trees in this forest. For smaller trees, competition was an important cause of death, as trees that were found standing dead had a slower growth rate (diameter increment) than survivors.3.Individual species showed different mortality patterns. Betula died more often and Fagus less often than expected from their abundance. Betula, Fagus and Tilia were mainly wind-thrown, whereas for Alnus and Fraxinus, 50% of the mortality was observed as standing dead trees.4.Both wind and competition are important mortality factors in Draved Forest.
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| 5. |
- Moore, Jason W., 1971-
(author)
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Environmental crises and the metabolic rift in world-historical perspective
- 2000
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In: Organization & environment. - 1086-0266 .- 1552-7417. ; 13:2, s. 123-157
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Journal article (peer-reviewed)abstract
- This article proposes a new theoretical framework to study the dialectic of capital and nature over the longue durée of world capitalism. The author proposes that today’s global ecological crisis has its roots in the transition to capitalism during the long sixteenth century. The emergence of capitalism marked not only a decisive shift in the arenas of politics, economy, and society, but a fundamental reorganization of world ecology, characterized by a “metabolic rift,” a progressively deepening rupture in the nutrient cycling between the country and the city. Building upon the historical political economy of Marx, Foster, Arrighi, and Wallerstein, the author proposes a new research agenda organized around the concept of systemic cycles of agro-ecological transformation. This agenda aims at discerning the ways in which capitalism’s relationship to nature developed discontinuously over time as recurrent ecological crises have formed a decisive moment of world capitalist crisis, forcing successive waves of restructuring over long historical time.
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| 6. |
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| 7. |
- Ekström, Magnus, 1966-
(author)
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Quantifying spatial patterns of landscapes
- 2003
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In: Ambio. - 0044-7447 .- 1654-7209. ; 32:8, s. 573-576
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Journal article (peer-reviewed)abstract
- In this paper we discuss information theoretical landscape indices based on data from digitized maps in grid format: measures based on Shannon's entropy, e.g. the measures of diversity and contagion; and measures based on conditional entropy, e.g. a new index which can be seen as an alternative to the measure of contagion that does not have the disadvantage of being highly correlated to the measure of diversity. We also introduce a measurement on how much information Is contained in a coarse-scale map about a fine-scale map.
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| 8. |
- Lidestav, Gun, et al.
(author)
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Introducing gender in studies on management behaviour among non-industrial private forest owners
- 2000
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In: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 15:3, s. 378-386
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Journal article (peer-reviewed)abstract
- The genderization of non-industrial private forest (NIPF) ownership creates different conditions for male and female forest owners. To compare male and female forest management behaviour and to examine whether observed differences should be understood in terms of gender, data from the Swedish National Board of Forestry's interview inquiry were used. Differences in frequency of harvesting and silvicultural operations were examined by binary logistic regression and differences in harvesting volume were tested by a multiple regression analysis. In all analyses sex of the owner was introduced as one of the explanatory variables. The sex of the owner was found to have a significant effect on the frequency of harvesting, cleaning and supplementary planting, but not on planting and mechanized scarification. In the cases when the sex of the owner was a significant factor, the degree of activity among the female owners was found to be lower. Results regarding harvested volumes did not expose ally significant differences in harvesting management strategies between male and female owners.
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| 9. |
- Lövgren, Mattias, et al.
(author)
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The PRC-barrel domain of the ribosome maturation protein RimM mediates binding to ribosomal protein S19 in the 30S ribosomal subunits
- 2004
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In: RNA. - : Cold Spring Harbor Laboratory Press (CSHL). - 1355-8382 .- 1469-9001. ; 10:11, s. 1798-1812
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Journal article (peer-reviewed)abstract
- The RimM protein in Escherichia coli is associated with free 30S ribosomal subunits but not with 70S ribosomes. A DeltarimM mutant is defective in 30S maturation and accumulates 17S rRNA. To study the interaction of RimM with the 30S and its involvement in 30S maturation, RimM amino acid substitution mutants were constructed. A mutant RimM (RimM-YY-->AA), containing alanine substitutions for two adjacent tyrosines within the PRC beta-barrel domain, showed a reduced binding to 30S and an accumulation of 17S rRNA compared to wild-type RimM. The (RimM-YY-->AA) and DeltarimM mutants had significantly lower amounts of polysomes and also reduced levels of 30S relative to 50S compared to a wild-type strain. A mutation in rpsS, which encodes r-protein S19, suppressed the polysome- and 16S rRNA processing deficiencies of the RimM-YY-->AA but not that of the DeltarimM mutant. A mutation in rpsM, which encodes r-protein S13, suppressed the polysome deficiency of both rimM mutants. Suppressor mutations, found in either helices 31 or 33b of 16S rRNA, improved growth of both the RimM-YY-->AA and DeltarimM mutants. However, they suppressed the 16S rRNA processing deficiency of the RimM-YY-->AA mutant more efficiently than that of the DeltarimM mutant. Helices 31 and 33b are known to interact with S13 and S19, respectively, and S13 is known to interact with S19. A GST-RimM but not a GST-RimM(YY-->AA) protein bound strongly to S19 in 30S. Thus, RimM likely facilitates maturation of the region of the head of 30S that contains S13 and S19 as well as helices 31 and 33b.
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| 10. |
- Moore, Jason W., 1971-
(author)
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Nature and the transition from feudalism to capitalism
- 2003
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In: Review: A Journal of the Fernand Braudel Center. - 0147-9032. ; 26:2, s. 97-172
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Journal article (peer-reviewed)abstract
- An epochal transformation of nature-society relations was inscribed in the transition from feudalism to capitalism. This article advances three central propositions. First, the origins of today’s global ecological crisis are found in the emergence of the capitalist world-economy in the “long” sixteenth century - not in industrialization, population growth, or market expansion, as the conventional wisdom would have it. Secondly, the crisis of feudalism was a general crisis not only of medieval Europe’s political economy, but in equal measure an expression of feudalism’s underlying ecological contradictions. Thirdly, the rise of capitalism effected a radical recomposition of world ecology. As early as the sixteenth century, we can see how the emergent logic of capital, which at once implies endless expansion and seeks to flatten socio-ecological diversity, undermined the possibilities for a sustainable relation between nature and society. Capitalism thus differed radically from feudalism and all other precapitalist formations. Where earlier ecological crises had been local, capitalism globalized them. From this standpoint, the origins of capitalism may shed light on today’s ecological crises.
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