| 1. |
- Wallensten, Anders, et al.
(författare)
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Surveillance of influenza A virus in migratory waterfowl in northern Europe
- 2007
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Ingår i: Emerging Infectious Diseases. - 1080-6040. - 1080-6040 ; 13:3, s. 404-411
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Tidskriftsartikel (refereegranskat)abstract
- We conducted large-scale, systematic sampling of influenza type A virus in migratory waterfowl (mostly mallards [Anas platyrhynchos]) at Ottenby Bird Observatory, southeast Sweden. As with previous studies, we found a higher prevalence in fall than spring, and among juveniles compared with adults. However, in contrast to other studies, we found that prevalence in spring was sometimes high (mean 4.0%, highest 9.5%). This finding raises the possibility that ducks are capable of perpetuating influenza A virus of different subtypes and subtype combinations throughout the year and from 1 year to the next. Isolation of the H5 and H7 subtypes was common, which suggests risk for transmission to sensitive domestic animals such as poultry. We argue that wild bird screening can function as a sentinel system, and we give an example of how it could have been used to forecast a remote and deadly outbreak of influenza A in poultry.
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| 2. |
- Järhult, Josef D., et al.
(författare)
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Environmental levels of the antiviral oseltamivir induce development of resistance mutation H274Y in influenza A/H1N1 virus in mallards.
- 2011
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Ingår i: PLoS ONE. - 1932-6203. ; 6:9, s. e24742
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Tidskriftsartikel (refereegranskat)abstract
- Oseltamivir (Tamiflu®) is the most widely used drug against influenza infections and is extensively stockpiled worldwide as part of pandemic preparedness plans. However, resistance is a growing problem and in 2008-2009, seasonal human influenza A/H1N1 virus strains in most parts of the world carried the mutation H274Y in the neuraminidase gene which causes resistance to the drug. The active metabolite of oseltamivir, oseltamivir carboxylate (OC), is poorly degraded in sewage treatment plants and surface water and has been detected in aquatic environments where the natural influenza reservoir, dabbling ducks, can be exposed to the substance. To assess if resistance can develop under these circumstances, we infected mallards with influenza A/H1N1 virus and exposed the birds to 80 ng/L, 1 µg/L and 80 µg/L of OC through their sole water source. By sequencing the neuraminidase gene from fecal samples, we found that H274Y occurred at 1 µg/L of OC and rapidly dominated the viral population at 80 µg/L. IC₅₀ for OC was increased from 2-4 nM in wild-type viruses to 400-700 nM in H274Y mutants as measured by a neuraminidase inhibition assay. This is consistent with the decrease in sensitivity to OC that has been noted among human clinical isolates carrying H274Y. Environmental OC levels have been measured to 58-293 ng/L during seasonal outbreaks and are expected to reach µg/L-levels during pandemics. Thus, resistance could be induced in influenza viruses circulating among wild ducks. As influenza viruses can cross species barriers, oseltamivir resistance could spread to human-adapted strains with pandemic potential disabling oseltamivir, a cornerstone in pandemic preparedness planning. We propose surveillance in wild birds as a measure to understand the resistance situation in nature and to monitor it over time. Strategies to lower environmental levels of OC include improved sewage treatment and, more importantly, a prudent use of antivirals.
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| 3. |
- Wallensten, Anders, et al.
(författare)
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Multiple gene segment reassortment between Eurasian and American lineages of influenza A virus (H6N2) in Guillemot (Uria aalge).
- 2005
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Ingår i: Archives of Virology. - 0304-8608. - 0304-8608 ; 150:8, s. 1685-92
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Tidskriftsartikel (refereegranskat)abstract
- Guillemots banded in the northern Baltic Sea were screened for influenza A virus (IAV). Three out of 26 sampled birds tested positive by RT-PCR. Two of these were characterized as subtype H6N2. Phylogenetic analyses showed that five gene segments belonged to the American avian lineage of IAVs, whereas three gene segments belonged to the Eurasian lineage. Our findings indicate that avian IAVs may have a taxonomically wider reservoir spectrum than previously known and we present the first report of a chimeric avian IAV with genes of American and Eurasian origin in Europe.
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| 4. |
- Deutschmann, Mats, 1964-, et al.
(författare)
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“Let’s Keep it Informal, Guys”
- 2008
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Ingår i: Tidskrift för lärarutbildning och forskning. - Umeå : The faculty board for teacher education. - ISSN 1404-7659. ; 15:2, s. 36-58
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Tidskriftsartikel (refereegranskat)abstract
- The paper explores the quantity and quality of communication produced by teachers in Internet courses of academic English, particularly during the initial stages of course activity. The courses are entirely conducted in virtual learning environments without physical meetings, and are part of the Bachelor programme (A–C level) of English at Mid Sweden University. The pedagogic design of the courses is based on collaborative learning, which presupposes a communicative environment with positive interdependence and interaction, where knowledge is shared by students questioning and challenging each other. Consequently, the teacher’s role in setting communicative norms which encourage an environment of high acceptance, where students feel that they can express their opinions freely, is of utmost importance. The results suggest that there are two important factors that affect student activity in the initial stages of an online course: how much the teacher communicates with the class and the manner in which he or she does so.
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| 5. |
- Persson, Anitha, et al.
(författare)
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Buffering effect of a prophyactic gel on dental plaque in institutionalised elderly
- 2007
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Ingår i: GERODONTOLOGY. - 0734-0664. ; 24:2, s. 98
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The effect of multiple daily applications of a prophylactic gel, with buffering substances, on plaque acidogenicity in elderly institutionalised individuals was evaluated. Background: Many elderly suffer from reduced salivary flow, poor oral hygiene and increased levels of cariogenic bacteria and are considered to be at an increased risk for coronal and root caries. Reinforcing the buffering capacity of dental plaque by the addition of substances such as bicarbonate and phosphates may decrease their caries activity. Materials and methods: Fourteen elderly, with subjective dry mouth, were treated for 16-day-periods at random with: (i) Profylin fluoride gel with buffering components; (ii) Profylin fluoride gel without buffering components and (iii) rinsing with water. Applications were made four times a day and each period was followed by a 2-week wash-out period. The plaque pH was registered after a carbohydrate challenge and the following were recorded before and after each test period: stimulated salivary secretion rate, buffer capacity, number Colony Farming Units (CFU) mutans streptococci, lactobacilli and a sample of Candida albicans on oral mucosa. Results: Eleven participants (mean age 76.6 years) fulfilled the study. Changes in plaque pH measurements, when calculated as area under the curve (AUC(6.2) and AUC(5.7)) values (pH x min), before and after each of the three treatments, showed no significant differences. A tendency to a higher plaque acidogenicity and amount of cariogenic microorganisms was found after the gel treatments. C. albicans was found in low levels. Conclusion: Frequent applications of the gel did not result in an improved neutralising effect in the elderly. This may be caused by a combination of several factors, such as the level of oral dryness of the individuals and low solubility, release and retention of the gel substances in plaque. Instead, an increased plaque acidogenicity was noted.
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| 6. |
- Sofrata, Abier H, et al.
(författare)
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Strong antibacterial effect of miswak against oral microorganisms associated with periodontitis and caries.
- 2008
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Ingår i: Journal of periodontology. - 0022-3492. ; 79:8, s. 1474-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The chewing stick (miswak) is used for oral hygiene in many parts of the world. In addition to the mechanical removal of plaque, an antibacterial effect has been postulated; however, tests of miswak extract from Salvadora persica (Arak) disclosed only low to moderate antibacterial effects. This may be attributable to the extraction process. Our aim was to test in vitro the antibacterial effect of miswak pieces, without extraction, on bacteria implicated in the etiology of periodontitis and caries. METHODS: Miswak pieces were standardized by size and weight (0.07 and 0.14 g) and tested against Streptococcus mutans, Lactobacillus acidophilus, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, and, as a reference, Haemophilus influenzae. The miswak pieces were tested in two ways: embedded in the agar plate or suspended above the agar plate. RESULTS: The inhibitory effect was most pronounced on P. gingivalis, A. actinomycetemcomitans, and H. influenzae, less on S. mutans, and least on L. acidophilus. Suspended miswak had comparable or stronger effects than miswak embedded in agar. The 0.14-g suspended miswak exhibited significantly greater inhibition on A. actinomycetemcomitans and H. influenzae than the 0.14-g miswak embedded in agar (P<0.01 and P<0.001, respectively). CONCLUSIONS: Miswak embedded in agar or suspended above the agar plate had strong antibacterial effects against all bacteria tested. The antibacterial effect of suspended miswak pieces suggests the presence of volatile active antibacterial compounds.
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| 7. |
- Bladh, Stina, et al.
(författare)
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Psychometric performance of a generic walking scale (Walk-12G) in Multiple Sclerosis and Parkinson's disease
- 2012
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Ingår i: Journal of Neurology. - Heidelberg : Springer Berlin/Heidelberg. - 0340-5354. ; 259:4, s. 729-738
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Tidskriftsartikel (refereegranskat)abstract
- Walking difficulties are common in neurological and other disorders, as well as among the elderly. There is a need for reliable and valid instruments for measuring walking difficulties in everyday life since existing gait tests are clinician rated and focus on situation specific capacity. The Walk-12G was adapted from the 12-item multiple sclerosis walking scale as a generic patient-reported rating scale for walking difficulties in everyday life. The aim of this study is to examine the psychometric properties of the Walk-12G in people with multiple sclerosis (MS) and Parkinson’s disease (PD). The Walk-12G was translated into Swedish and evaluated qualitatively among 25 people with and without various neurological and other conditions. Postal survey (MS, n = 199; PD, n = 189) and clinical (PD, n = 36) data were used to test its psychometric properties. Respondents considered the Walk-12G relevant and easy to use. Mean completion time was 3.5 min. Data completeness was good (<5% missing item responses) and tests of scaling assumptions supported summing item scores to a total score (corrected item-total correlations >0.6). Coefficient alpha and test–retest reliabilities were >0.9, and standard errors of measurement were 2.3–2.8. Construct validity was supported by correlations in accordance with a priori expectations. Results are similar to those with previous Walk-12G versions, indicating that scale adaptation was successful. Data suggest that the Walk-12G meets rating scale criteria for clinical trials, making it a valuable complement to available gait tests. Further studies involving other samples and application of modern psychometric methods are warranted to examine the scale in more detail.
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| 8. |
- Lindahl, Britt, et al.
(författare)
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Socio-scientific Issues : A Way to Improve Students’ Interest and Learning?
- 2011
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Ingår i: US-China Education Review B. - David Publishing Company. - 2161-6248. ; 1:3, s. 342-347
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Tidskriftsartikel (refereegranskat)abstract
- According to many documents, there is a strong need to renew science education. One way could be to work with SSI (socio-scientific issues). This paper reports on both students' and teachers' experiences and learning when working with socio-scientific issues in science education in secondary school (aged from 13 to 16). The approach is multidimensional, as factors that influence cognition as well as motivation and the forming of attitudes are complex. Results suggest that SSI work forms are more important than personal factors for explaining outcomes. Relevant issues, autonomy and functioning group work seem to be important aspects of successful SSI work together with structure provided by the teacher, and information that challenges previous knowledge. In general, SSI seems to be most efficient for students, who believe that they learn from presenting and discussing their knowledge, focus on "the large picture", acknowledge own responsibility for learning, find school science personally relevant and are self-efficacious. It seems that the outcomes from SSI work are much in the hands of the teacher. This paper is a short summary of the first year and quantitative part of the project. Further results from the project will later be found in our homepage (http://www.sisc.se).
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| 9. |
- Collin, Betty, et al.
(författare)
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The origin of Vibrio cholerae influences uptake and persistence in the blue mussel Mytilus edulis
- 2012
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Ingår i: Journal of Shellfish Research. - 0730-8000. ; 31:1, s. 87-92
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Tidskriftsartikel (refereegranskat)abstract
- Vibrio cholerae may cause diarrheal diseases and wound infections, both of which have the potential to be fatal. Transmission to humans is often linked to consumption of contaminated shellfish/drinking water or dermal exposure to water (e.g. when swimming). In this study, we investigated whether different isolates of Vibrio cholerae differ in terms of accumulation, persistence, and viability when encountering blue mussels (Mytilus edulis). Mussel uptake and elimination of three different V. cholerae strains were compared: one fatal clinical non-O1/O139 isolate, one highly potent El Tor biotype, and one marine strain isolated from blue mussels. The results showed that the uptake of the marine strain was significantly higher than the clinical strain, but the elimination process of the marine strain was also more efficient. The El Tor strain was not at all ingested by the mussels. In addition, the survival of bacteria when incubated together with M. edulis hemocytes was tested in vitro. The viability of clinical strains was unaffected by the presence of hemocytes, and the marine strains were even more resistant and able to multiply. We conclude that the highly virulent El Tor biotype was not taken up by the mussels and could thereby escape the mussels' elimination process. The potentially fatal non-O1/O139 V. cholerae strain may accumulate in low numbers, but could be very persistent in mussels.
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| 10. |
- Dessborn, Lisa, et al.
(författare)
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Innate responses of mallard ducklings towards aerial, aquatic and terrestrial predators
- 2012
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Ingår i: Behaviour. - 0005-7959. ; 149:13-14, s. 1299-1317
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Tidskriftsartikel (refereegranskat)abstract
- Reproductive success in ducks is strongly influenced by predation on the breeding grounds. Ducklings are targeted by a range of terrestrial, aerial and aquatic predators, giving a strong selective advantage to individuals and broods that have effective ways to avoid predation. In experiments on naive mallard (Anas platyrhynchos) ducklings without an accompanying adult female we investigated the innate ability to identify and avoid threats at varying intensity from aerial, aquatic and terrestrial predators. Ducklings displayed increased vigilance in response to pre-recorded calls of predatory birds, representing a low level of threat. They did not react to visual and olfactory stimuli generated by motionless northern pike (Esox lucius). Neither did they show a strong response to caged American mink (Neovison vison) (visual and olfactory stimuli), although they avoided the area with the mink, indicating a certain level of recognition. High intensity threats were simulated by staging attacks from aerial (goshawk, Accipiter gentilis) and aquatic predators (northern pike). The aerial attack made ducklings dive and scatter under water, whereas the response to attack by pike was to run on the water and scatter in different directions. The lack of response to a ‘passive’ pike and the rather weak avoidance of mink indicate that olfactory cues are not as important in identifying a potential predatory threat by ducklings as are auditory cues. Visual cues appear to be of little importance unless they are combined with movement, and a clear response is only triggered when the intensity of predator threat is high. Mallard ducklings, thus, show an innate capacity to adjust anti-predator behaviour to different predator types and to threat intensity. Our study highlights the general trade-off between foraging needs and predator avoidance, but also second-order trade-offs in which innate avoidance behaviour towards one type of predator may increase predation risk from another.
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