| 1. |
- Algesten, Grete, 1974-, et al.
(författare)
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Seasonal variation of CO2 saturation in the Gulf of Bothnia : Indications of marine net heterotrophy
- 2004
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Ingår i: Global Biogeochemical Cycles. - Washington, D.C : American Geophysical Union (AGU). - 0886-6236 .- 1944-9224. ; 18, s. 4021-4028
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Tidskriftsartikel (refereegranskat)abstract
- Seasonal variation of pCO2 and primary and bacterioplankton production were measured in the Gulf of Bothnia during an annual cycle. Surface water was supersaturated with CO2 on an annual basis, indicating net heterotrophy and a source of CO2 to the atmosphere. However, the Gulf of Bothnia oscillated between being a sink and a source of CO2 over the studied period, largely decided by temporal variation in bacterial respiration (BR) and primary production (PP) in the water column above the pycnocline. The calculated annual respiration-production balance (BR-PP) was very similar to the estimated CO2 emission from the Gulf of Bothnia, which indicates that these processes were major determinants of the exchange of CO2 between water and atmosphere. The southern basin (the Bothnian Sea) had a lower net release of CO2 to the atmosphere than the northern Bothnian Bay (7.1 and 9.7 mmol C m−2 d−1, respectively), due to higher primary production, which to a larger extent balanced respiration in this basin.
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| 2. |
- Fredin, Ola, 1972-
(författare)
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Mountain centered icefields in northern Scandinavia
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mountain centered glaciers have played a major role throughout the last three million years in the Scandinavian mountains. The climatic extremes, like the present warm interglacial or cold glacial maxima, are very short-lived compared to the periods of intermediate climate conditions, characterized by the persistence of mountain based glaciers and ice fields of regional size. These have persisted in the Scandinavian mountains for about 65% of the Quaternary. Mountain based glaciers thus had a profound impact on large-scale geomorphology, which is manifested in large-scale glacial landforms such as fjords, glacial lakes and U-shaped valleys in and close to the mountain range.Through a mapping of glacial landforms in the northern Scandinavian mountain range, in particular a striking set of lateral moraines, this thesis offers new insights into Weichselian stages predating the last glacial maximum. The aerial photograph mapping and field evidence yield evidence that these lateral moraines were overridden by glacier ice subsequent to their formation. The lateral moraines were dated using terrestrial cosmogenic nuclide techniques. Although the terrestrial cosmogenic nuclide signature of the moraines is inconclusive, an early Weichselian age is tentatively suggested through correlations with other landforms and stratigraphical archives in the region. The abundance and coherent spatial pattern of the lateral moraines also allow a spatial reconstruction of this ice field. The ice field was controlled by topography and had nunataks protruding also where it was thickest close to the elevation axis of the Scandinavian mountain range. Outlet glaciers discharged into the Norwegian fjords and major valleys in Sweden.The process by which mountain based glaciers grow into an ice sheet is a matter of debate. In this thesis, a feedback mechanism between debris on the ice surface and ice sheet growth is presented. In essence, the growth of glaciers and ice sheets may be accelerated by an abundance of debris in their ablation areas. This may occur when the debris cover on the glacier surface inhibits ablation, effectively increasing the glaciers mass balance. It is thus possible that a dirty ablation area may cause the glacier to advance further than a clean glacier under similar conditions. An ice free period of significant length allows soil production through weathering, frost shattering, and slope processes. As glaciers advance through this assemblage of sediments, significant amounts of debris end up on the surface due to both mass wastage and subglacial entrainment. Evidence that this chain of events may occur, is given by large expanses of hummocky moraine (local name Veiki moraine) in the northern Swedish lowlands. Because the Veiki moraine has been correlated with the first Weichselian advance following the Eemian, it implies a heavily debris charged ice sheet emanating from the mountain range and terminating in a stagnant fashion in the lowlands.
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| 3. |
- Jansson, Patrik, 1972, et al.
(författare)
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A Framework for Polytypic Programming on Terms, with an Application to Rewriting
- 2000
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Ingår i: Workshop on Generic Programming.
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Konferensbidrag (refereegranskat)abstract
- Rewriting is a typical example of a polytypic function. Given any value of a datatype (an algebra of terms), and rules to rewrite values of that datatype, we want a function that rewrites the value to normal form if the value is normalizable. This paper develops a polytypic rewriting function that uses the parallel innermost rewriting strategy. It improves upon our earlier work on polytypic rewriting in two fundamental ways. Firstly, the rewriting function uses a term interface that hides the polytypic part from the rest of the program. The term interface is a framework for polytypic programming on terms. This implies that the rewriting function is independent of the particular implementation of polytypism. We give several functions and laws on terms, which simplify calculating with programs. Secondly, the rewriting function is developed together with a correctness proof. We just present the result of the correctness proof, the proof itself is published elsewhere.
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| 4. |
- Jansson, Patrik, 1972, et al.
(författare)
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Polytypic Data Conversion Programs
- 2002
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Ingår i: Science of Computer Programming. - 0167-6423. ; 43:1, s. 35-75
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Tidskriftsartikel (refereegranskat)abstract
- Several generic programs for converting values from regular datatypes to some other format, together with their corresponding inverses, are constructed. Among the formats considered are shape plus contents, compact bit streams and pretty printed strings. The different data conversion programs are constructed using John Hughes arrow combinators along with a proof that printing (from a regular datatype to another format) followed by parsing (from that format back to the regular datatype) is the identity. The printers and parsers are described in PolyP, a polytypic extension of the functional language Haskell.
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| 5. |
- Woldegiorgis, Andreas, et al.
(författare)
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Nanowires for surface enlargement of narrow-bore fused-silica tubing
- 2004
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Ingår i: Electrophoresis. - : Wiley. - 0173-0835 .- 1522-2683. ; 25:21-22, s. 3660-3668
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Tidskriftsartikel (refereegranskat)abstract
- A method for preparation of silica nanowires with dimensions of d = 10-100 nm, 5-500 nm, is described. The nanostructured material is an integral part of the inner surface of narrow bore fused-silica capillary tubing. The wire preparation method is based on a decomposition of 2-chloro-1,1,2-trifluoroethyl methyl ether at elevated temperature and pressure. The silica bulk material is rearranged via a sustained silica-hydrogen fluoride chemistry, and reaction mechanisms for this process are proposed. The method is suitable for preparing long lengths of tubing with the modified surface. It is our belief that the texture of the capillary wall with its increased surface area is useful for applications such as microreactions, catalysis, and high-resolution pressure and/or electrodriven open-tubular liquid chromatography.
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