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- Abrandt Dahlgren, Madeleine, 1956-, et al.
(författare)
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Questioning to learn and learning to question : Structure and function of PBL scenarios in environmental science education.
- 2000
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Ingår i: Second International Conference on Problem-Based Learning in Higher Education,2000.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In problem-based learning, scenarios relating to real life are used as a point of departure for the learning process. Even though the importance of suitable cases or scenarios to bring about a fruitful learning process is emphasised in the literature, few studies focus on how they actually function in the learning process. This study focuses on how the scenarios used in a ten-week introductory course of a new four-year, undergraduate programme in environmental science functioned in terms of the structure and content of the questions they evoked. Data were gathered through diary notes from nine groups of students, comprising 5-8 students per group. The data were subjected to a qualitative analysis aimed at describing the structure and content of the questions generated by the groups. Five different kinds of questions were identified and labelled; A. Encyclopaedic, B. Meaning-oriented, C. Relational, D. Value-oriented and E. Solution-oriented. All scenarios generated questions pertaining to all five categories in all groups, but the emphasis varied. The results are discussed in relation to the design of scenarios, and in relation to students’ approaches to learning.
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| 3. |
- Abrandt Dahlgren, Madeleine, 1956-, et al.
(författare)
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Questioning to learn and learning to question : Structure and function of problem-based learning scenarios in environmental science education
- 2001
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Ingår i: Higher Education. - 0018-1560 .- 1573-174X. ; 41:3, s. 263-282
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Tidskriftsartikel (refereegranskat)abstract
- In problem-based learning, scenarios relating to real life are used as a point of departure for the learning process. Even though the importance of suitable cases or scenarios in bringing about a fruitful learning process is emphasised in the literature, few studies focus on how they actually function in the learning process. This study focuses on how the scenarios used in a ten-week introductory course of a new four-year undergraduate programme in environmental science functioned in terms of the structure and content of the questions they evoked. Data were gathered through diary notes from nine groups of students, comprising 5-8 students per group. The data were subjected to a qualitative analysis aimed at describing the structure and content of the questions generated by the groups. Five different kinds of questions were identified and labelled, encyclopaedic, meaning-oriented, relational, value-oriented and solution-oriented. All scenarios generated questions pertaining to all five categories in all groups, but the emphasis varied. The results are discussed in relation to the design of scenarios, and in relation to students' approaches to learning.
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| 6. |
- Hjelm, Olof, 1967-, et al.
(författare)
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Production of organically bound halogens by the litter-degrading fungus Lepista nuda
- 1999
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Ingår i: Soil Biology and Biochemistry. - 0038-0717 .- 1879-3428. ; 31:11, s. 1510-1515
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Tidskriftsartikel (refereegranskat)abstract
- The ability of Lepista nuda to produce organically bound halogens was tested both in a laboratory study of a pure culture and in a field study. It was found that L. nuda caused an increase in the total amount of organically bound halogens in the study of a pure culture, but possibly because of large variance between replicates, no such increase could be detected in the field study. In addition, in both the laboratory and the field studies, low-molecular-weight organohalogens such as chlorinated benzaldehydes were detected in all samples affected by the fungus and the amounts were 0.2–82 μg/g d.w. These low-molecular-weight compounds correspond to approximately 30% of the increase in organohalogens detected in the laboratory study. It is suggested that the low-molecular-weight organohalogens detected, most likely are produced de novo by L. nuda and that production of such compounds followed by an incorporation into high-molecular-weight compounds is an explanation for the increase in amounts in the laboratory study.
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| 7. |
- Johansson, Emma, 1971-, et al.
(författare)
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Organic chlorine in deciduous and coniferous forest soils in southern Sweden
- 2003
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Ingår i: Soil science. - : Ovid Technologies (Wolters Kluwer Health). - 0038-075X .- 1538-9243. ; 168:5, s. 347-355
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Tidskriftsartikel (refereegranskat)abstract
- The concentration of organic chlorine (Clorg) was determined in soil samples collected in the O-horizon in forest soils in southern Sweden to describe differences among stand types and elucidate the influence of chloride (Clinorg), pH, and organic carbon. The samples were collected within the Swedish National Survey of Forest Soils and Vegetation, with moraine as the dominating soil type and with granite and gneiss as bedrock. The concentration of organic chlorine (Clorg) found in the deciduous forest soils was significantly lower than that in the coniferous forest soils. The Clorg increased with Clinorg, organic carbon content, and decreasing pH but was most strongly correlated to Clinorg. Crosswise comparisons among the variables showed that the influence of Clinorg overrode the influence of pH and organic carbon. We concluded that the major driving force in the formation of Clorg in soils is deposition of Clinorg and that the difference among deciduous and coniferous stands is due primarily to a higher input of Clinorg in the canopy of coniferous trees as a result of a larger wet and dry deposition in coniferous compared with deciduous forests. The concentration of Clorg decreased significantly from June to August. This follows the pattern of chloride deposition in the region and gives further evidence that Clinorg is a driving force in the formation of Clorg in soil. The results of the present study gives further evidence that the turnover of Clorg is closely related to the turnover of Clinorg and that it is necessary to include Clorg in the assessment of the biogeochemical cycling of chlorine in the environment.
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| 8. |
- Johansson, Emma, 1971-, et al.
(författare)
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Spatial patterns of organic chlorine and chloride in Swedish forest soil
- 2003
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Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 52:2, s. 391-397
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Tidskriftsartikel (refereegranskat)abstract
- The concentration of organic carbon, organic chlorine and chloride was determined in Swedish forest soil in the southern part of Sweden and the spatial distribution of the variables were studied. The concentration of organically bound chlorine was positively correlated to the organic carbon content, which is in line with previous studies. However, the spatial distribution patterns strongly indicate that some other variable adds structure to the spatial distribution of organic chlorine. The distribution patterns for chloride strongly resembled the distribution of organic chlorine. The spatial distribution of chloride in soil depends on the deposition pattern which in turn depends on prevailing wind-direction, amount of precipitation and the distance from the sea. This suggests that the occurrence of organic chlorine in soil is influenced by the deposition of chloride of some variable that co-varies with chloride. Two clearly confined strata were found in the area: the concentrations of organic chlorine and chloride in the western area were significantly higher than in the eastern area. No such difference among the two areas was seen regarding the carbon content.
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| 9. |
- Karlsson, Susanne, 1967-, et al.
(författare)
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UV-light induced mineralization of organic matter bound chlorine in Lake BjΣn, Sweden - A laboratory study
- 2003
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Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 52:2, s. 463-469
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Tidskriftsartikel (refereegranskat)abstract
- Surface water and aqueous solutions of isolated organic matter from a humic rich lake in southern Sweden were exposed to artificial UV radiation to investigate the UV light induced influence on organic matter bound chlorine in natural systems. It was found that the photodegradation of organic matter bound chlorine was more pronounced than the photodegradation of organic carbon. After 120 h of irradiation of the isolated organic matter, only 35% of the initial organochlorine was still in the solution compared to about 70% of the dissolved organic carbon (DOC). A similar result was obtained for unfractionated surface water. Furthermore, our results indicate that the loss of organic chlorine was mainly due to a mineralization of organic chlorine into chloride ions. The total decrease of organic chlorine after 120 h was 32 ╡g Clorg l-1, of which the major part disappeared in the initial irradiation phase. A similar increase was observed in the chloride concentration (34 ╡g Cl- l-1).
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