| 1. |
- Pinay, Gilles, et al.
(författare)
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Patterns of denitrification rates in European alluvial soils under various hydrological regimes
- 2007
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Ingår i: Freshwater Biology. - 0046-5070 .- 1365-2427. - 0046-5070 ; 52:2, s. 252-266
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Tidskriftsartikel (refereegranskat)abstract
- 1. Denitrification in floodplain soils is one of the main biological processes emitting and reducing nitrous oxide, a greenhouse gas, and the main process responsible for the buffering capacity of riparian zones against diffuse nitrate pollution. 2. The aim of this study was to measure denitrification rates under a wide range of current climatic conditions and hydrological regimes in Europe (from latitude 64 degrees N to latitude 42 degrees N and from longitude 2 degrees W to longitude 25 degrees E), in order to determine the response patterns of this microbial process under different climatic and hydrological conditions, and to identify denitrification proxies robust enough to be used at the European scale. 3. Denitrification activity was significant in all the floodplain soils studied whatever the latitude. However, we found an increase in rates of an order of magnitude from high to mid latitudes. Maximum rates (above 30 g N m(-2) month(-1)) were measured in the maritime conditions of the Trent floodplain. These rates are similar to mineralisation rates measured in alluvial soils and of the same order of magnitude as the amount of N stored in herbaceous plants in alluvial soils. 4. We used Multivariate Adaptative Regression Splines to relate the response variable denitrification with five relevant predictors, namely soil moisture, temperature, silt plus clay, nitrate content and herbaceous plant biomass. 5. Soil moisture, temperature, and nitrate were the three main control variables of microbial denitrification in alluvial soils in decreasing order of importance. 6. The model developed for denitrification with interaction effects outperformed a pure additive model. Soil moisture was involved in all interactions, emphasising its importance in predicting denitrification. 7. These results are discussed in the context of scenarios for future change in European hydrological regimes.
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| 2. |
- Beltran-Pardo, Eliana, et al.
(författare)
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Sequence analysis of the DNA-repair gene rad51 in the tardigrades Milnesium cf. tardigradum, Hypsibius dujardini and Macrobiotus cf. harmsworthi
- 2013
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Ingår i: Journal of limnology. - 1129-5767 .- 1723-8633. ; 72:s1, s. 80-91
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Tidskriftsartikel (refereegranskat)abstract
- Tardigrades are known for being resistant to extreme conditions, including tolerance to ionising and UV radiation in both the hydratedand the dehydrated state. It is known that these factors may cause damage to DNA. It has recently been shown that single and double DNAstrand breaks occur when tardigrades are maintained for a long time in the anhydrobiotic state. This may suggest that perhaps tardigrades rely on efficient DNA repair mechanisms. Among all proteins that comprise the DNA repair system, recombinases such as RecA or Rad51 have a very important function: DNA exchange activity. This enzyme is used in the homologous recombination and allows repair of thedamaged strand using homologous non-damaged strands as a template. In this study, Rad51 induction was evaluated by western blot in Milnesium cf. tardigradum, after exposure to gamma radiation. The Rad51 protein was highly induced by radiation, when compared to the control. The rad51 genes were searched in three tardigrades: Milnesium cf. tardigradum, Hypsibius dujardini and Macrobiotus cf. harmsworthi. The gene sequences were obtained by preparing and sequencing transcriptome libraries for H. dujardini and M. cf. harmsworthi and designing rad51 degenerate primers specific for M. cf. tardigradum. Comparison of Rad51 putative proteins from tardigrades with other organisms showed that they are highly similar to the corresponding sequence from the nematode Trichinella spiralis. A structure-based sequence alignment from tardigrades and other organisms revealed that putative Rad51 predicted proteins from tardigrades contain the expected motifs for these important recombinases. In a cladogram tree based on this alignment, tardigrades tend to cluster together suggesting that they have selective differences in these genes that make them diverge between species. Predicted Rad51 structures from tardigrades were also compared with crystalline structure of Rad51 in Saccharomyces cerevisiae. These results reveal that S. cerevisiae Rad51 structure is very similar to that of the three analysed tardigrades. On the other hand the predicted structure of Rad51 from M. cf. harmsworthi and H. dujardini are closer related to each other, than each of them to that of M. cf. tardigradum.
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| 3. |
- Jönsson, Ingemar, 1959-, et al.
(författare)
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Tolerance to gamma-irradiation in eggs of the tardigrade Richtersius coronifer depends on stage of development
- 2013
-
Ingår i: Journal of limnology. - 1129-5767 .- 1723-8633. ; 72:s1, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- Tardigrades are known as one of the most radiation tolerant animals on Earth, and several studies on tolerance in adult tardigrades have been published. In contrast, very few studies on radiation tolerance of embryonic stages have been reported. Here we report a study on tolerance to gamma irradiation in eggs of the eutardigrade Richtersius coronifer. Irradiation of eggs collected directly from a natural substrate (moss) showed a clear dose-response, with a steep decline in hatchability at doses up to 0.4 kGy followed by a relatively constant hatchability around 25% up to 2 kGy, and a decline to ca. 5% at 4 kGy above which no eggs hatched. Analysis of the time required for eggs to hatch after irradiation (residual development time) showed that hatching of eggs after exposure to high doses of gamma radiation was associated with short residual development time. Since short residual development time means that the egg was irradiated at a late developmental stage, this suggests that eggs were more tolerant to radiation late in development. This was also confirmed in another experiment in which stage of development at irradiation was controlled. No eggs irradiated at the early developmental stage hatched, and only one egg at middle stage hatched, while eggs irradiated in the late stage hatched at a rate indistinguishable from controls. This suggests that the eggs are more sensitive to radiation in the early stages of development, or that tolerance to radiation is acquired only late in development, shortly before the eggs hatch, hypotheses that are not mutually exclusive. Our study emphasizes the importance of considering specific cell cycle phases and developmental stages in studies of tolerance to radiation in tardigrades, and the potential importance of embryonic studies in revealing the mechanisms behind the radiation tolerance of tardigrades and other cryptobiotic animals.
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| 4. |
- Suhonen, Riitta, et al.
(författare)
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Cross-cultural validity of the Individualised Care Scale – a Rasch model analysis
- 2013
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Ingår i: Journal of Clinical Nursing. - : Wiley-Blackwell. - 0962-1067 .- 1365-2702. ; 22:5-6, s. 648-660
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Tidskriftsartikel (refereegranskat)abstract
- Aims and objectives. The aim of this study was to investigate, using Rasch model analysis, the measurement invariance of the item ratings of the Individualised Care Scale. Background. Evidence of reliability is needed in cross-cultural comparative studies. To be used in different cultures and languages, the items must function the same way. Design. A methodological and comparative design. Methods. Secondary analysis of data, gathered in 2005–2006 from a cross-cultural survey using the Individualised Care Scale from Finnish, Greek, Swedish and English predischarge hospitalised orthopaedic and trauma patients (n = 1093), was used. The Rasch model, which produces calibrations (item locations and rank) and item fit statistics, was computed using the Winstep program. Results. The rank of average Individualised Care Scale item calibrations (−2·26–1·52) followed a generally similar trend (Infit ≤ 1·3), but slight differences in the item rank by country were found and some item misfit was identified within the same items. There was some variation in the order and location of some Individualised Care Scale items for individual countries, but the overall pattern of item calibration was generally corresponding. Conclusions. The Rasch model provided information about the appropriateness, sensitivity and item function in different cultures providing more in-depth information about the psychometric properties of the Individualised Care Scale instrument. Comparison of the four versions of the Individualised Care Scale – patient revealed general correspondence in the item calibration patterns although slight differences in the rank order of the items were found. Some items showed also a slight misfit. Based on these results, the phrasing and targeting of some items should be considered. Relevance to clinical practice. The Individualised Care Scale – Patient version can be used in cross-cultural studies for the measurement of patients’ perceptions of individualised care. Information obtained with the use of the Individualised Care Scale in clinical nursing practice is important, and valid measures are needed in evaluating patients’ assessment of individualised care, one indicator of care quality.
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| 5. |
- Suhonen, Riitta, et al.
(författare)
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European orthopaedic and trauma patients' perceptions of nursing care : a comparative study
- 2009
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Ingår i: Journal of Clinical Nursing. - 0962-1067 .- 1365-2702. ; 18:20, s. 2818-2829
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To compare English, Finnish, Greek and Swedish orthopaedic and trauma patients' perceptions of nursing care received during hospitalisation. BACKGROUND: Patient perceptions are important when evaluating nursing care delivery. Evaluations usually take place sub-nationally though European citizens may be treated throughout the European Union. International comparative studies are possible because of the universal nature and philosophical roots of quality in nursing care. They are needed to assist in improving care outcomes. DESIGN: A cross-sectional, comparative study design was used. METHOD: The Schmidt Perception of Nursing Care Survey was used to obtain data from orthopaedic and trauma patients in acute hospitals in four countries: Finland (n = 425, response rate 85%), Greece (n = 315, 86%), Sweden (n = 218, 73%) and UK (n = 135, 85%). Data were first analysed using descriptive statistics, then between-country comparisons were computed inferentially using a one-way analysis of variance and a univariate analysis of covariance. RESULTS: Between-country differences were found in patients' perceptions of the nursing care received. Over the whole Schmidt Perception of Nursing Care Survey the Swedish and Finnish patients gave their care the highest assessments and the Greek patients the lowest. The same trend was seen in each of the four sub-scales: Seeing The Individual Patient, Explaining, Responding and Watching. Responding was given the highest assessments in each participating country and Seeing the Individual Patient the lowest except in Greece. CONCLUSIONS: Further research is needed to consider whether the between-country differences found are caused by differences between cultures, nursing practices, roles of healthcare personnel or patients in the different countries. The Schmidt Perception of Nursing Care Survey is suitable for the assessment of European orthopaedic and trauma patients' perceptions of nursing care received during hospitalisation. RELEVANCE TO CLINICAL PRACTICE: The results are useful in evaluating and developing nursing care in hospitals from different European countries.
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| 6. |
- Andersson, Jens A, et al.
(författare)
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User profiling for pre-fetching or caching in a catch-up TV network
- 2016
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Ingår i: 2016 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB). - 9781467390446
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Konferensbidrag (refereegranskat)abstract
- We investigate the potential of different pre-fetching and/or caching strategies for different user behaviour with respect to surfing or browsing in a catch-up-TV network. To this end we identify accounts and channels associated with strong or weak surfing or browsing respectively and study the distributions of hold times for the different types of behaviour. Finally we present results from a request prediction model and a caching simulation for the different types of behaviour and find that the results are relatively similar.
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| 7. |
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| 8. |
- Asher, Itay, et al.
(författare)
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The educative and scalable functions of authoring tools to support inquiry-based science learning
- 2010
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Konferensbidrag (refereegranskat)abstract
- Specialized authoring tools enable non-programmers to develop computer-based learning environments that reflect a particular task model. Large-scale implementation of novel but pedagogically sound environments is made possible if the resulting environments reflect the intended essential pedagogical features. We explore the balance between constraints and generativity through five teams' experiences with a specialized authoring tool, STOCHASMOS. We hope to spark a critical discussion of the role of specialized authoring tools in scalability. We also suggest that future research examine the educative function of these tools.
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| 9. |
- Beltran-Pardo, Eliana A., et al.
(författare)
-
Sequence analysis of the DNA-repair gene rad51 in the tardigrades Milnesium cf. tardigradum, Hypsibius dujardini and Macrobiotus cf. harmsworthi
- 2013
-
Ingår i: Journal of limnology. - : PAGEPress Publications. - 1129-5767 .- 1723-8633. ; 72, s. 80-91
-
Tidskriftsartikel (refereegranskat)abstract
- Tardigrades are known for being resistant to extreme conditions, including tolerance to ionising and UV radiation in both the hydrated and the dehydrated state. It is known that these factors may cause damage to DNA. It has recently been shown that single and double DNA strand breaks occur when tardigrades are maintained for a long time in the anhydrobiotic state. This may suggest that perhaps tardigrades rely on efficient DNA repair mechanisms. Among all proteins that comprise the DNA repair system, recombinases such as RecA or Rad51 have a very important function: DNA exchange activity. This enzyme is used in the homologous recombination and allows repair of the damaged strand using homologous non-damaged strands as a template. In this study, Rad51 induction was evaluated by western blot in Milnesium cf. tardigradum, after exposure to gamma radiation. The Rad51 protein was highly induced by radiation, when compared to the control. The rad51 genes were searched in three tardigrades: Milnesium cf. tardigradum, Hypsibius dujardini and Macrobiotus cf. harmsworthi. The gene sequences were obtained by preparing and sequencing transcriptome libraries for H. dujardini and M. cf. harmsworthi and designing rad51 degenerate primers specific for M. cf. tardigradum. Comparison of Rad51 putative proteins from tardigrades with other organisms showed that they are highly similar to the corresponding sequence from the nematode Trichinella spiralis. A structure-based sequence alignment from tardigrades and other organisms revealed that putative Rad51 predicted proteins from tardigrades contain the expected motifs for these important recombinases. In a cladogram tree based on this alignment, tardigrades tend to cluster together suggesting that they have selective differences in these genes that make them diverge between species. Predicted Rad51 structures from tardigrades were also compared with crystalline structure of Rad51 in Saccharomyces cerevisiae. These results reveal that S. cerevisiae Rad51 structure is very similar to that of the three analysed tardigrades. On the other hand the predicted structure of Rad51 from M. cf. harmsworthi and H. dujardini are closer related to each other, than each of them to that of M. cf. tardigradum.
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| 10. |
- Jönsson, Ingemar, et al.
(författare)
-
Tolerance to gamma-irradiation in eggs of the tardigrade Richtersius coronifer depends on stage of development
- 2013
-
Ingår i: Journal of limnology. - : PAGEPress Publications. - 1129-5767 .- 1723-8633. ; 72, s. 73-79
-
Tidskriftsartikel (refereegranskat)abstract
- Tardigrades are known as one of the most radiation tolerant animals on Earth, and several studies on tolerance in adult tardigrades have been published. In contrast, very few studies on radiation tolerance of embryonic stages have been reported. Here we report a study on tolerance to gamma irradiation in eggs of the eutardigrade Richtersius coronifer. Irradiation of eggs collected directly from a natural substrate (moss) showed a clear dose-response, with a steep decline in hatchability at doses up to 0.4 kGy followed by a relatively constant hatchability around 25% up to 2 kGy, and a decline to ca. 5% at 4 kGy above which no eggs hatched. Analysis of the time required for eggs to hatch after irradiation (residual development time) showed that hatching of eggs after exposure to high doses of gamma radiation was associated with short residual development time. Since short residual development time means that the egg was irradiated at a late developmental stage, this suggests that eggs were more tolerant to radiation late in development. This was also confirmed in another experiment in which stage of development at irradiation was controlled. No eggs irradiated at the early developmental stage hatched, and only one egg at middle stage hatched, while eggs irradiated in the late stage hatched at a rate indistinguishable from controls. This suggests that the eggs are more sensitive to radiation in the early stages of development, or that tolerance to radiation is acquired only late in development, shortly before the eggs hatch, hypotheses that are not mutually exclusive. Our study emphasizes the importance of considering specific cell cycle phases and developmental stages in studies of tolerance to radiation in tardigrades, and the potential importance of embryonic studies in revealing the mechanisms behind the radiation tolerance of tardigrades and other cryptobiotic animals.
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