| 1. |
- 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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| 2. |
- Bahr, Adam, et al.
(författare)
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Long-term changes in vegetation and soil chemistry in a calcareous and sandy semi-natural grassland
- 2012
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Ingår i: Flora: Morphology, Distribution, Functional Ecology of Plants. - : Elsevier BV. - 0367-2530. ; 207:5, s. 379-387
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Tidskriftsartikel (refereegranskat)abstract
- Calcicole plant species are vulnerable to acidification and fertilization, caused by deposition and changes in land use, since they are adapted to nutrient-poor calcareous conditions. In this study we used vegetation data (vascular plants, bryophytes and lichens) from 1964 and 1985 and stored soil samples from 1966 to investigate long-term soil chemistry and vegetation changes in a semi-natural, sandy calcareous grassland in southern Sweden. In the re-investigation in 2008 we found that increased decalcification due to acidification could not be verified. The plant community had changed from stress-tolerant calcareous grassland towards a community promoted by higher nutrient availability. Furthermore, the cover of species indicating calcareous conditions had decreased. A decline in the cover of species adapted to alkaline, phosphorus-poor conditions may be due to increased nutrient availability, but there were also indications that the vegetation had changed due to overgrowth by woody plants. This long-term impoverishment of the plant community highlights the need for appropriate management of calcareous grasslands, in order to limit the nutrients available in the soil and prevent overgrowth by shrubs and trees. (C) 2012 Published by Elsevier GmbH.
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| 3. |
- Dicksved, Johan, et al.
(författare)
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Susceptibility to Campylobacter Infection Is Associated with the Species Composition of the Human Fecal Microbiota
- 2014
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Ingår i: mBio. - 2161-2129 .- 2150-7511. ; 5:5, s. e01212-14-
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Tidskriftsartikel (refereegranskat)abstract
- The gut microbiota is essential for human health, but very little is known about how the composition of this ecosystem can influence and respond to bacterial infections. Here we address this by prospectively studying the gut microbiota composition before, during, and after natural Campylobacter infection in exposed poultry abattoir workers. The gut microbiota composition was analyzed with 16S amplicon sequencing of fecal samples from poultry abattoir workers during the peak season of Campylobacter infection in Sweden. The gut microbiota compositions were compared between individuals who became culture positive for Campylobacter and those who remained negative. Individuals who became Campylobacter positive had a significantly higher abundance of Bacteroides (P = 0.007) and Escherichia (P = 0.002) species than those who remained culture negative. Furthermore, this group had a significantly higher abundance of Phascolarctobacterium (P = 0.017) and Streptococcus (P = 0.034) sequences than the Campylobacter-negative group, which had an overrepresentation of Clostridiales (P = 0.017), unclassified Lachnospiraceae (P = 0.008), and Anaerovorax (P = 0.015) sequences. Intraindividual comparisons of the fecal microbiota compositions yielded small differences over time in Campylobacter-negative participants, but significant long-term changes were found in the Campylobacter-positive group (P < 0.005). The results suggest that the abundance of specific genera in the microbiota reduces resistance to Campylobacter colonization in humans and that Campylobacter infection can have long-term effects on the composition of the human fecal microbiota. IMPORTANCE Studies using mouse models have made important contributions to our understanding of the role of the gut microbiota in resistance to bacterial enteropathogen colonization. The relative abundances of Escherichia coli and Bacteroides species have been pointed out as important determinants of susceptibility to Gram-negative pathogens in general and Campylobacter infection in particular. In this study, we assessed the role of the human gut microbiota in resistance to Campylobacter colonization by studying abattoir workers that are heavily exposed to these bacteria. Individuals with a certain composition of the gut microbiota became culture positive for Campylobacter. As their microbiotas were characterized by high abundances of Bacteroides spp. and E. coli, well in line with the findings with mouse models, these bacterial species likely play an important role in colonization resistance also in humans.
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| 4. |
- Ellström, Carl, et al.
(författare)
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Exciton fine structure splitting in InP quantum dots in GaInP
- 2007
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 1361-648X .- 0953-8984. ; 19:29
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the electronic structure of excitons in InP quantum dots in GaInP. The exciton is theoretically expected to have four states. Two of the states are allowed to optically decay to the ground ( vacuum) state in the dipole approximation. We see these two lines in photoluminescence (PL) experiments and find that the splitting between the lines ( the fine structure splitting) is 150(+/- 30) mu eV. The lines were perpendicularly polarized. We verified that the lines arise from neutral excitons by using correlation spectroscopy. The theoretical calculations show that the polarization of the emission lines are along and perpendicular to the major axis of elongated dots. The fine structure splitting depends on the degree of elongation of the dots and is close to zero for dots of cylindrical symmetry, despite the influence of the piezoelectric polarization, which is included in the calculation.
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| 5. |
- Ellström, Carl, et al.
(författare)
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Investigations of InAs surface dots on InP
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:3
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Tidskriftsartikel (refereegranskat)abstract
- We have fabricated InAs dots on the surface of InP, determined their structure, and measured the optical transition energy. This energy was found to be in excellent agreement with theoretical calculations, where no free parameters have been used. The calculations were performed using eight-band k center dot p theory in the envelope function approximation. We conclude that this theory is adequate to describe quantum dots also when one of the confining materials is vacuum. (c) 2006 American Institute of Physics.
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| 6. |
- Fällman, Fredrik, et al.
(författare)
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Kina förändrar världen
- 2005
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Ingår i: Svenska dagbladet. - 1101-2412. ; :21 mars, s. 21-
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 7. |
- Hallqvist, Anders, et al.
(författare)
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The many faces of biographical learning
- 2012
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Ingår i: Studies in the Education of Adults. - 0266-0830 .- 1478-9833. ; 44:1, s. 70-84
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Tidskriftsartikel (refereegranskat)abstract
- Our aim in this article is to look for more diversity within the concept of biographical leaning. As a conceptual tool for investigating learning in life transitions, biographical learning has gained some recognition over recent years. The concept centres on people’s abilities and possibilities to cope with change in a rapidly changing environment. As transitions have become more common, ‘learning processes within transition’ has become an important area for educational research. The development of the concept of biographical learning is related to this trend, since biographical learning processes appear to be more explicitly triggered when a person’s life course is changing and people are faced with transitions in it. In this article, biographical learning will be discussed in relation to research on restructuring, job loss and enforced work transitions. The article will suggest that such transitions may be understood in terms of biographical learning, acknowledging that learning in work transitions is not only about ensuring one’s ‘professional competence’ or ‘employability’ but includes identity issues and decision-making that affect one’s biography. Alheit and Dausien portray biographical learning as a certain perspective on lifelong learning, suggesting a ‘shift in analytic perspective’ and a departure from the policy-focused view in which lifelong learning is framed by political and economic precepts. Acknowledging the inner tensions between the ‘instrumentalist’ and ‘emancipative’ power of lifelong learning, the authors place some confidence in the latter, calling for an outlook in which the learning individual ‘is taken more seriously’. There are empirical reasons for such a preference. Although traditional lifeworlds are eroding, people’s responses are not inevitably a ‘panic’ reaction. Instead, people cope with changes rather creatively by using different action strategies that affect both their own biography and the social world in which they live. The concept of biographical learning is regarded as useful in this context, firstly because it takes account both of social structures and of the individual’s subjectivity. Hence, it recognizes people’s sense of being able to control their own lives interacting with biographical and structural conditions. Even though life chances are unequally distributed and agency is always ‘bounded’, when people face transitions decisions must be made and actions taken that are affected by and affect their biography. Secondly, biographical learning could be considered valuable because its scope is wider than predominant lifelong learning policies and because its aim extends beyond instrumental skills and ‘employability’. Thirdly, biographical learning can be regarded as helpful because it includes not only formal and organized aspects of learning, but also ‘cognitive and reflexive dimensions of learning as much as the emotional, embodied, pre-reflexive and non-cognitive aspects of everyday learning processes and practices’. However, further investigations of the concept are called for, as pointed out by Alheit and Dausien. One possible development concerns challenging its somewhat uniform character. While Alheit has identified three current ‘biographical coping patterns’ (‘patchworking’, ‘networking’ and ‘designing’; Alheit, 1999, p. 75), further analysis will probably reveal new insights and perhaps lead to a more complex description of what biographical learning is. It seems reasonable to assume, for example, that there might be differences between more continuous and more disruptive versions of biographical learning. In order to encompass a wider spectrum of approaches, the aim of this paper is to analyse, explore and expand the notion of biographical learning and to suggest a number of different modes of such learning.
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| 8. |
- Hallqvist, Anders
(författare)
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Work Transitions as Biographical Learning : Exploring the Dynamics of Job Loss
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, researchers have pointed out that individuals understand their lives to a great extent through narratives and narration. In the field of adult education this idea has been taken up for instance in the concept of biographical learning. This thesis discusses the concept of biographical learning in relation to a research project on job loss in mid-life, as it is experienced and handled by whitecollar workers in a Swedish context. While much of the previous research on job loss and unemployment has focused on causes and effects, coping strategies and job search behaviour, this study suggests that an enforced work transition can be thought of as a biographical learning process.It also suggests that a greater diversity in the learning concept can be attained by reconsidering the concept in the framework of a pragmatist’s view of action. Analysing narrative interviews with white-collar workers (n=23), the study finds diversity in biographical learning with respect to the relative weights and characters of creative action and reflexive identity work. Individual’s variety of engagement in a work transition has also been understood by theoretically describing the process as structured by particular choice junctures. The study finds that a job loss during particular circumstances furthers reconsiderations, novel career decisions and ‘horizontal’ career moves.Being a central part of biographical learning, reflexivity is used in moments of evaluation, when people tell stories about the transition. It should be discussed in the plural, as the variety of evaluations implies a variety of reflexive efforts. Furthermore, it emphasizes that a work transition is a relational project, pointing out the significance of strong ties and formal ties to people who consider ‘horizontal’ career moves during a work transition. Altogether, this suggests that practical, existential, rhetorical as well as relational issues are involved in work transitions and biographical learning. Keywords: biographical learning, work transition, job loss, adult learning, adult education, outplacement counselling.
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| 9. |
- Larsson, Staffan, 1947-, et al.
(författare)
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Vuxnas lärande - en profil vid Linköpings universitet
- 1999
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- En rapport som utgör ett underlag för filosofisk fakultets beslut om startegi för området vuxnas lärande, t. exstart av forskarskola, interkontinental master och andra synergier mellan olika grupper, som verkar på området.
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| 10. |
- Lindemann, Kristina, et al.
(författare)
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Serum lipids and endometrial cancer risk: results from the HUNT-II study.
- 2009
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Ingår i: International journal of cancer. Journal international du cancer. - : Wiley. - 1097-0215. ; 124:12, s. 2938-41
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is a major risk factor for endometrial cancer. Still, the association of obesity-related metabolic factors, such as serum lipids and lipoprotein levels, is unclear. We prospectively examined the association of serum levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol, non-high-density lipoprotein (non-HDL), and HDL cholesterol with endometrial cancer risk among 31,473 women. During 9 years of follow-up, 100 cases of endometrial cancer were identified by linkage to the Cancer Registry of Norway. There was a positive association of serum triglyceride levels with endometrial cancer risk. Comparing the highest to the lowest quartile of triglycerides, the age-adjusted hazard ratio was 2.34 (95% CI: 1.04-5.28), and further adjustment for body mass index attenuated the association (hazard ratio 1.79, 95% CI: 0.79-4.05). For total serum cholesterol, low-density lipoprotein cholesterol and HDL cholesterol there were no associations with endometrial cancer risk, either without or after adjustment for body mass index. Serum triglyceride levels were positively associated with the risk of endometrial cancer, and some of the association seems to be attributable to obesity. Apart from higher estrogen levels produced in adipose tissue, mechanisms more specifically related to triglycerides may also be involved in endometrial cancer. Further prospective studies on this subject are needed to better understand the association of blood lipids with endometrial cancer risk.
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