| 1. |
|
|
| 2. |
- Cairns, D.M., et al.
(författare)
-
Influences of animal activity on treeline position and pattern: Implications for treeline responses to climate change
- 2007
-
Ingår i: Physical geography. - : Informa UK Limited. - 0272-3646 .- 1930-0557. ; 28:5, s. 419-433
-
Tidskriftsartikel (refereegranskat)abstract
- The alpine treeline is a potentially sensitive indicator of vegetation response to climate change. However, there is not a generally accepted single hypothesis that explains treeline position and pattern at multiple scales. Recently a set of five hypotheses has been proposed for treeline explanations (Körner, 2003b). The impacts of animals are not explicitly included in any of these hypotheses, however, they can and should be included. In this review we discuss Körner's five hypotheses and explain how animal activity can be included within them to make them more applicable to treeline environments experiencing a changing climate. We utilize the conceptual model proposed by Cairns and Moen (2004) as an organizing framework for the inclusion of animal activity with existing hypotheses. Finally we suggest that the equivocal nature of treeline response to climate change may be in part related to animal activity.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Charoenrat, Theppanya, et al.
(författare)
-
Oxygen-limited fed-batch process : an alternative control for Pichia pastoris recombinant protein processes
- 2005
-
Ingår i: Bioprocess and biosystems engineering (Print). - : Springer Science and Business Media LLC. - 1615-7591 .- 1615-7605. ; 27:6, s. 399-406
-
Tidskriftsartikel (refereegranskat)abstract
- An oxygen-limited fed-batch technique (OLFB) was compared to traditional methanol-limited fed-batch technique (MLFB) for the production of recombinant Thai Rosewood beta-glucosidase with Pichia pastoris. The degree of energy limitation, expressed as the relative rate of respiration (q(O)/q(O,max)), was kept similar in both the types of processes. Due to the higher driving force for oxygen transfer in the OLFB, the oxygen and methanol consumption rates were about 40% higher in the OLFB. The obligate aerobe P. pastoris responded to the severe oxygen limitation mainly by increased maintenance demand, measured as increased carbon dioxide production per methanol, but still somewhat higher cell density (5%) and higher product concentrations (16%) were obtained. The viability was similar, about 90-95%, in both process types, but the amount of total proteins released in the medium was much less in the OLFB processes resulting in substantially higher (64%) specific enzyme purity for input to the downstream processing.
|
|
| 7. |
- Moen, Jon, et al.
(författare)
-
Factors structuring the treeline ecotone in Fennoscandia
- 2008
-
Ingår i: Plant Ecology & Diversity. - : Taylor & Francis. - 1755-0874 .- 1755-1668. ; 1:1, s. 77-87
-
Tidskriftsartikel (refereegranskat)abstract
- Many hypotheses have been put forward to explain the structure and position of alpine treelines. The spatial complexity of the ecotone, ranging from sharp boundaries to networks of tree patches within a heath matrix, may explain why no consensus has been reached. In this paper, we discuss factors from abiotic disturbances to herbivory that may help understand the spatial structure of the alpine treeline ecotone in Fennoscandia. The ecotone is dominated by mountain birch (Betula pubescens ssp. tortuosa), and may show a wide range of spatial structures. We discuss the influence of topography, seed limitations, seedling establishment, growth limitations, abiotic disturbances and herbivory as structuring factors. All of these factors may operate, but their relative importance in space and time is unknown. There is a basic difference between factors that prevent the establishment of trees, and thus act on early life history stages, and factors that thin out a previously dense forest, and thus act on adult trees. Mortality caused directly or indirectly by geometrid moths may belong to the latter category. We suggest that seedling and sapling mortality is more important than seed limitation for the establishment of new individuals in the treeline ecotone. Important mortality factors may be abiotic disturbances, competition (or allelopathy) from field layer plants and herbivory. The relative role of these factors needs to be examined further.
|
|
| 8. |
|
|
