| 1. |
- Andersson, Bo, Docent, 1965-, et al.
(författare)
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Developing M-Services : Lessons Learned From the Developers Perspective.
- 2007
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Ingår i: Communications of the Association for Information Systems. - : Association for Information Systems. - 1529-3181 .- 1529-3181. ; 20:38, s. 605-620
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Tidskriftsartikel (refereegranskat)abstract
- In recent years the Swedish Police Force (SPF) have encountered greater demands on availability and 24/7 services when dealing with errands that are regarded as low priority compared to regular police work, e.g. collecting tips from the public. One attempt to meet these increasing demands was the development of a mobile communications platform that allowed the public to communicate easily with the SPF using their own mobile phones by sending SMS and MMS. The focus of this paper is on the early phases of development of this m-service, in particular, on the specific technical issues such as interoperability and standards used by the actors on the scene affecting the development of mobile information systems. The learning experiences are as follows: First, mobile communication platforms have a large potential for contributing to the field of emergency management information systems since they can be based on open and nationally accepted standards. Second, global and national standards for sending multimedia messages are not always truly standardized. Operators and mobile phone manufacturers make minor alterations and interpretations of the standard and thereby some of the benefits found in standards disappear. Third, when developing mobile information systems we suggest and recommend that the analysis phase should be enhanced compared to traditional system development, and it should address the interoperability between mobile phones on one hand and operators on the other hand.
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| 2. |
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| 3. |
- Bring, Torun, et al.
(författare)
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Colour development in copper ruby alkali silicate glasses : Part 1. The impact of tin (II) oxide, time and temperature
- 2007
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Ingår i: Glass Technology, Eur J Glass Sci Technol A. - : Society of Glass Technology. ; 48:2, s. 101-108
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Tidskriftsartikel (refereegranskat)abstract
- The development of the red colour in copper ruby alkali silicate glasses has been studied by means of ultraviolet/visible spectroscopy, TEM and EXAFS. The results show that in both red and slightly overstruck, brownish glasses the colour is due to clusters of metallic copper. Before striking non-coloured glasses contain mainly cuprous ions, Cu+. Tin acts as a reducing agent but also has an accelerating effect on colour development.
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| 4. |
- Eriksson, Mattias, et al.
(författare)
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Fluorescence Fe II lines as traces of fast outflows of white dwarf winds
- 2007
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Ingår i: Baltic Astronomy. - 1392-0049. ; 16:01, s. 95-97
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Tidskriftsartikel (refereegranskat)abstract
- A set of equations are put into a code forming a procedure to derive intensities of fluorescence lilies based on both physical properties of the fluorescent plasma and its location relative to the origin of the pumping emission. In a first test, the code is applied to symbiotic stars, and effort is made to explain the circumstances under which the two known Fell channels pumped by C IV are activated. For the channel at 1548.204 angstrom, which is most frequently observed to be active, there is a good agreement between the results of the calculations and the observed Fell line strengths. Fluorescence lines resulting from pumping through the other channel at 1548.411 angstrom can occur, according to the results of the calculations, only in the systems where a fast outflow from the white dwarf wind is present. The evidences of the white dwarf winds are found in the literature for all the symbiotic systems in which observation of the Fell fluorescence lines from the w(2)D(3/2) level is reported.
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| 5. |
- Hansson, Lars-Anders, et al.
(författare)
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Escape from UV threats in zooplankton: A cocktail of behavior and protective pigmentation
- 2007
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 88:8, s. 1932-1939
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Tidskriftsartikel (refereegranskat)abstract
- In order to avoid environmental threats, organisms may respond by altering behavior or phenotype. Using experiments performed in high-latitude Siberia and in temperate Sweden, we show for the first time that, among freshwater crustacean zooplankton, the defense against threats from ultraviolet radiation (UV) is a system where phenotypic plasticity and behavioral escape mechanisms function as complementary traits. Freshwater copepods relied mainly on accumulating protective pigments when exposed to UV radiation, but Daphnia showed strong behavioral responses. Pigment levels for both Daphnia and copepods were generally higher at higher latitudes, mirroring different UV threat levels. When released from the UV threat, Daphnia rapidly reduced (within 10 days) their UV protecting pigmentation-by as much as 40%-suggesting a cost in maintaining UV protective pigmentation. The. evolutionary advantage of protective pigments is, likely, the ability to utilize the whole water column during daytime; conversely, since the amount of algal food is generally higher in surface waters, unpigmented individuals are restricted to a less preferred feeding habitat in deeper waters. Our main conclusion is that different zooplankton taxa, and similar taxa at different latitudes, use different mixes of behavior and pigments to respond to UV radiation.
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| 6. |
- Holst, Anders, et al.
(författare)
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Weyl product algebras and modulation spaces
- 2007
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Ingår i: Journal of Functional Analysis. - : Elsevier BV. - 0022-1236. ; 251:2, s. 463-491
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Tidskriftsartikel (refereegranskat)abstract
- We discuss algebraic properties of the Weyl product acting on modulation spaces. For a certain class of weight functions omega we prove that M-(omega)(p,q) is an algebra under the Weyl product if p epsilon [1, infinity] and 1 <= q <= min(p, p '). For the remaining cases P epsilon [1, infinity] and min(p, p ') < q <= infinity we show that the unweighted spaces M-p,M-q are not algebras under the Weyl product. (C) 2007 Elsevier Inc. All rights reserved.
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| 7. |
- Pommier, Thomas, et al.
(författare)
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Global patterns of diversity and community structure in marine bacterioplankton
- 2007
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Ingår i: Molecular Ecology. - : Blackwell Publishing Ltd. - 0962-1083 .- 1365-294X. ; 16:4, s. 867-880
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Tidskriftsartikel (refereegranskat)abstract
- Because of their small size, great abundance and easy dispersal, it is often assumed that marine planktonic microorganisms have a ubiquitous distribution that prevents any structured assembly into local communities. To challenge this view, marine bacterioplankton communities from coastal waters at nine locations distributed world-wide were examined through the use of comprehensive clone libraries of 16S ribosomal RNA genes, used as operational taxonomic units (OTU). Our survey and analyses show that there were marked differences in the composition and richness of OTUs between locations. Remarkably, the global marine bacterioplankton community showed a high degree of endemism, and conversely included few cosmopolitan OTUs. Our data were consistent with a latitudinal gradient of OTU richness. We observed a positive relationship between the relative OTU abundances and their range of occupation, i.e. cosmopolitans had the largest population sizes. Although OTU richness differed among locations, the distributions of the major taxonomic groups represented in the communities were analogous, and all local communities were similarly structured and dominated by a few OTUs showing variable taxonomic affiliations. The observed patterns of OTU richness indicate that similar evolutionary and ecological processes structured the communities. We conclude that marine bacterioplankton share many of the biogeographical and macroecological features of macroscopic organisms. The general processes behind those patterns are likely to be comparable across taxa and major global biomes.
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| 8. |
- Sitch, Stephen, et al.
(författare)
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Assessing the carbon balance of circumpolar Arctic tundra using remote sensing and process modeling
- 2007
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Ingår i: Ecological Applications. - : John Wiley & Sons. - 1051-0761 .- 1939-5582. ; 17:1, s. 213-234
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Tidskriftsartikel (refereegranskat)abstract
- This paper reviews the current status of using remote sensing and process-based modeling approaches to assess the contemporary and future circumpolar carbon balance of Arctic tundra, including the exchange of both carbon dioxide and methane with the atmosphere. Analyses based on remote sensing approaches that use a 20-year data record of satellite data indicate that tundra is greening in the Arctic, suggesting an increase in photosynthetic activity and net primary production. Modeling studies generally simulate a small net carbon sink for the distribution of Arctic tundra, a result that is within the uncertainty range of field-based estimates of net carbon exchange. Applications of processbased approaches for scenarios of future climate change generally indicate net carbon sequestration in Arctic tundra as enhanced vegetation production exceeds simulated increases in decomposition. However, methane emissions are likely to increase dramatically, in response to rising soil temperatures, over the next century. Key uncertainties in the response of Arctic ecosystems to climate change include uncertainties in future fire regimes and uncertainties relating to changes in the soil environment. These include the response of soil decomposition and respiration to warming and deepening of the soil active layer, uncertainties in precipitation and potential soil drying, and distribution of wetlands. While there are numerous uncertainties in the projections of process-based models, they generally indicate that Arctic tundra will be a small sink for carbon over the next century and that methane emissions will increase considerably, which implies that exchange of greenhouse gases between the atmosphere and Arctic tundra ecosystems is likely to contribute to climate warming.
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| 9. |
- Axelsson Olsson, Diana, et al.
(författare)
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Acanthamoeba-Campylobacter coculture as a novel method for enrichment of Campylobacter species
- 2007
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 73:21, s. 6864-6869
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we present a novel method to isolate and enrich low concentrations of Campylobacter pathogens. This method, Acanthamoeba-Campylobacter coculture (ACC), is based on the intracellular survival and multiplication of Campylobacter species in the free-living protozoan Acanthamoeba polyphaga. Four of the Campylobacter species relevant to humans and livestock, Campylobacter jejuni, C. coli, C. lari, and C. hyointestinalis, were effectively enriched by the coculture method, with growth rates comparable to those observed in other Campylobacter enrichment media. Studying six strains of C. jejuni isolated from different sources, we found that all of the strains could be enriched from an inoculum of fewer than 10 bacteria. The sensitivity of the ACC method was not negatively affected by the use of Campylobacter-selective antibiotics in the culture medium, but these were effective in suppressing the growth of seven different bacterial species added at a concentration of 10(4) CFU/ml of each species as deliberate contamination. The ACC method has advantages over other enrichment methods as it is not dependent on a microaerobic milieu and does not require the use of blood or other oxygen-quenching agents. Our study found the ACC method to be a promising tool for the enrichment of Campylobacter species, particularly from water samples with low bacterial concentrations.
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| 10. |
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