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- Sutton, Mark A., et al.
(author)
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Dynamics of ammonia exchange with cut grassland : Synthesis of results and conclusions of the GRAMINAE Integrated Experiment
- 2009
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In: Biogeosciences. - Goettingen : Nicolaus Copernicus University Press. - 1726-4170 .- 1726-4189. ; 6:12, s. 2907-2934
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Journal article (peer-reviewed)abstract
- Improved data on biosphere-atmosphere exchange are fundamental to understanding the production and fate of ammonia (NH3) in the atmosphere. The GRAMINAE Integrated Experiment combined novel measurement and modelling approaches to provide the most comprehensive analysis of the interactions to date. Major intercomparisons of micrometeorological parameters and NH3 flux measurements using the aerodynamic gradient method and relaxed eddy accumulation (REA) were conducted. These showed close agreement, though the REA systems proved insufficiently precise to investigate vertical flux divergence. Grassland management had a large effect on fluxes: emissions increased after grass cutting (−50 to 700 ng m-2 s-1 NH3) and after N-fertilization (0 to 3800 ng m-2 s -1) compared with before the cut (−60 to 40 ng m-2 s -1). © Author(s) 2009.
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| 4. |
- Bohman, Irene, et al.
(author)
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The timing for winter-growing shredder species and leaf litter turnover rate in an oligotrophic lake, SE Sweden
- 2006
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In: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 556:1, s. 99-108
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Journal article (peer-reviewed)abstract
- Small freshwater systems often depend on allochthonous organic subsidies to sustain productivity. Benthic invertebrates consuming coarse detritus maintain the energy flow by conveying dead organic matter into prey items and increase the food availability for other consumers. Compared to lotic systems, the dynamics of coarse detritus decomposition has not received much attention in lakes. The objectives of this study were to investigate the seasonality of leaf litter turnover and the timing of abundance of potential shredder species in a typical oligotrophic boreal lake. Leaf litter was experimentally exposed in litterbags in the littoral zone in Lake Välen from autumn to late spring two consecutive years. The weight loss rate of leaf litter initially followed the same pattern during both winter periods, but was markedly influenced by freezing in late winter the second year. Further, the seasonal variation patterns in abundance in litterbags were quite different among the potential shredder species. Only the limnephilid caddis larvae showed a density variation pattern possible to connect to the weight loss of leaf litter in litterbags. Otherwise frequent detritivores such as Asellus aquaticus and Leptophlebia marginata displayed lowest density in litterbags during the main weight loss period. However, after the long ice period the second winter the remaining leaf litter seemed to be consumed by A. aquaticus. With increasing knowledge of the initial leaf breakdown process and the guild of shredders in lakes, the decomposition rate may also in this habitat become a useful instrument when evaluating the impact from perturbations on ecosystem function.
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| 5. |
- Edvinsson, Tomas, et al.
(author)
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Intramolecular charge-transfer tuning of perylenes : Spectroscopic features and performance in Dye-sensitized solar cells
- 2007
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In: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 111:42, s. 15137-15140
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Journal article (peer-reviewed)abstract
- Five novel perylene molecules with different intramolecular charge-transfer (ICT) characters have been synthesized. The relation between the ICT character for different donating groups and the results for their electro- and photochemical properties as well as their performance in nanostructured dye-sensitized solar cells (nDSC) are reported. With the stronger donors, we obtain a shift of the lowest unoccupied molecular orbital (LUMO) to more negative potential versus normal hydrogen electrode (NHE) as well as an increase the charge separation in the dye upon excitation. Ab initio calculations were used to analyze the effects on orbital energies and electron distribution with the different donors. Incorporating the dyes in nDSCs, we see a drastical improvement in the performance for the more polar dyes. In particular, we find a much improved photovoltage because of higher LUMO levels, allowing conduction band tuning in the TiO2 as well as a contribution from the permanent dipoles in the dyes. The photocurrent improves remarkably with increasing ICT character of the dyes. The external quantum efficiency reached over 70%, and the overall solar-to-electrical energy conversion efficiency was improved to almost 4% for the dye with highest ICT character, which can be compared with devices with the standard N719 dye (Ru(dcbPY)(2)(NCS)(2)) showing 6% under similar conditions. The performance is a significant improvement compared to previous reports for perylenes and lifts the performance from modest to promising. Initial stability tests show that the dye with the highest performance was spectrally stable after more than 2000 h of irradiation in a solar-cell device.
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| 8. |
- Graham, Ian, et al.
(author)
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European guidelines on cardiovascular disease prevention in clinical practice: full text. Fourth Joint Task Force of the European Society of Cardiology and other societies on cardiovascular disease prevention in clinical practice (constituted by representatives of nine societies and by invited experts).
- 2007
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In: European journal of cardiovascular prevention and rehabilitation : official journal of the European Society of Cardiology, Working Groups on Epidemiology & Prevention and Cardiac Rehabilitation and Exercise Physiology. - : Oxford University Press (OUP). - 1741-8267. ; 14 Suppl 2
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Journal article (peer-reviewed)abstract
- Other experts who contributed to parts of the guidelines: Edmond Walma, Tony Fitzgerald, Marie Therese Cooney, Alexandra Dudina European Society of Cardiology (ESC) Committee for Practice Guidelines (CPG): Alec Vahanian (Chairperson), John Camm, Raffaele De Caterina, Veronica Dean, Kenneth Dickstein, Christian Funck-Brentano, Gerasimos Filippatos, Irene Hellemans, Steen Dalby Kristensen, Keith McGregor, Udo Sechtem, Sigmund Silber, Michal Tendera, Petr Widimsky, Jose Luis Zamorano Document reviewers: Irene Hellemans (CPG Review Co-ordinator), Attila Altiner, Enzo Bonora, Paul N. Durrington, Robert Fagard, Simona Giampaoli, Harry Hemingway, Jan Hakansson, Sverre Erik Kjeldsen, Mogens Lytken Larsen, Giuseppe Mancia, Athanasios J. Manolis, Kristina Orth-Gomer, Terje Pedersen, Mike Rayner, Lars Ryden, Mario Sammut, Neil Schneiderman, Anton F. Stalenhoef, Lale Tokgözoglu, Olov Wiklund, Antonis Zampelas
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| 10. |
- Herrmann, Jan, et al.
(author)
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Hornsjöns biologi 2004-2005
- 2006
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Reports (other academic/artistic)abstract
- Det kan troligen sägas att en höjning av vattenståndet med ca 10 cm bör inte ha allvarligare konsekvenser för sjöns biologi. Möjligen kan erhållas viss positiv effekt; igenväxning kanske kan bromsas något, se avsnittet om Vegetation. Men det bör också framhållas att gäddans situation i sjön och dess vandringsmöjligheter och leksituation bör beaktas och utvecklas i samband med planerade åtgärder.Vissa av de biologiska parametrar som nu studerats i Hornsjön har förut gjorts studier av, nämligen vegetation (Wallsten 1979), plankton och bottenfauna (Berggren 1979), fåglar (Rodebrand 1979) samt fisk och plankton (Aspengren 1985, Troschke 1987). För dessa organismgrupper görs vissa jämförelser mellan 70-talet och 2004/2005, dvs oftast knappt 30 år. Vissa jämförelser har gjorts med nämnda publikationer. En mer omfattande analys avses göras i en planerad rapport om sjöns biologi. Där skall alla kända biologiska fakta sammanfattas och kommenteras.
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