| 1. |
- Ekstam, Börje, et al.
(författare)
-
Predicting risk habitats for the transmission of the small liver fluke, Dicrocoelium dendriticum to grazing ruminants.
- 2011
-
Ingår i: Geospatial Health. - Naples, Italy : Global Network for Geospatial Health. - 1827-1987 .- 1970-7096. ; 6:1, s. 125-131
-
Tidskriftsartikel (refereegranskat)abstract
- A multiple regression model was used to analyse if the structure of vegetation and soil patches in grazed units (pastures) can be used as explanatory variables to predict the prevalence of Dicrocoelium dendriticum, a common parasite of cattle and sheep, in grazing cattle stocks on the Baltic island of Öland in southern Sweden.The scale dependency was evaluated by comparing three levels of spatial resolution of patches. Prevalence data were obtained from slaughtered animals.Our models predict that the prevalence of D. dendriticum increases in grazed areas with woody vegetation, whereas moist and wet areas decrease parasite prevalence. The predictive power of the statistical models increased with increasing level of patch resolution. Approximately 42% of the variation in parasite prevalence (angular transformation) was explained by the areal proportion of vegetation types (4th-root-transformed).Based on the results obtained, we believe that our model strategy provides a rational and systematic tool to identify habitats that carry risk for D. dendriticum infection of ruminants, and that it can be applied to other parasites with similar life cycles such as Fasciola hepatica.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Abdelgadir, Mohanad, et al.
(författare)
-
Distribution of denitrifiers predicted by correlative niche modeling of changing environmental conditions and future climatic scenarios across the Baltic Sea
- 2023
-
Ingår i: Ecological Informatics. - : Elsevier. - 1574-9541 .- 1878-0512. ; 78
-
Tidskriftsartikel (refereegranskat)abstract
- Denitrifying microbial communities provide an important ecosystem function in aquatic systems. Yet, knowledge on predictive and modeling of these complex and changing communities is limited. The emergently challenging question of how the geographical distribution of denitrifiers responds to ongoing and future environmental change is not yet fully understood. In our study we use metadata-based correlative niche modeling to analyze the geographical distribution of selected putative denitrifiers in the genus Sphingomonas, Mycoplana, Shewanella, and Alteromonas at different predicted environmental conditions and future climatic scenarios across the Baltic Sea. Using the predictive power of an ensemble modeling approach and eight different machine-learning algorithms, habitat suitability and the distribution of the selected denitrifiers were evaluated using geophysical and bioclimatic variables, benthic conditions, and four Representative Concentration Pathway (RCP) trajectories of future global warming scenarios. All algorithms provided successful prediction capabilities both for variable importance, and for habitat suitability with Area Under the Curve (AUC) values between 0.89 and 1.00. Model findings revealed that salinity and nitrate concentrations significantly explained the variation in distribution of the selected denitrifiers. Rising temperatures of 0.8 to 1.8 °C at future RCP60–2050 trajectories are predicted to diminish or eliminate the bioclimatic suitable habitats for denitrifier distributions across the Baltic Sea. Multi-collated terrestrial and marine environmental variables contributed to the successful prediction of denitrifier distributions within the study area. The correlative niche modeling approach with high AUC values presented in the study allowed for accurate projections of the future distributions of the selected denitrifiers. The modeling approach can be used to improve our understanding of how ongoing and predicted future environmental changes may affect habitat suitability for organisms with denitrification capacity across the Baltic Sea.
|
|
| 5. |
|
|
| 6. |
- Alzhanova-Ericsson, Alla T., et al.
(författare)
-
Lecture attendance is a pivotal factor for improving prospective teachers’ academic performance in Teaching and Learning Mathematics
- 2017
-
Ingår i: Journal of Further and Higher Education. - : Routledge. - 0309-877X .- 0013-1326. ; 41:1, s. 1-15
-
Tidskriftsartikel (refereegranskat)abstract
- The value and importance of lectures in higher education is part of a modern education discourse worldwide. This study aims to estimate the importance of lectures for prospective teachers of kindergarten, preschool and early primary school. We analysed academic achievements of prospective teachers who had either mandatorily or voluntarily attended lectures in the subject of teaching and learning mathematics. Students’ examination grades in a maths course with mandatory or voluntary lecture attendance were analysed with a logistic model testing the association between lecture attendance requirement and grades. We show that mandatory lecture attendance (1) more than double the odds of students receiving a pass grade when their situated and tacit knowledge was examined and (2) quadrupled the odds of students achieving the highest grade (pass with distinction) when both their understanding of elementary mathematics and their situated and tacit knowledge of teaching and learning mathematics were examined. Our study provides evidence for a significant positive role of lecture attendance for students acquiring skills in Teaching and Learning Mathematics. While attending lectures students receive situated tacit knowledge of the subject which is otherwise difficult, if not impossible, for them to obtain in a different way. The observed improvement may have an additional positive effect in being a step towards overcoming a maths anxiety, which is otherwise relatively common among prospective teachers.
|
|
| 7. |
- Alzhanova-Ericsson, Alla T, PhD, 1954-, et al.
(författare)
-
Multidisciplinary and Multimodal Approaches in Teaching and Learning Mathematics, Music and Language Based on the Flipped Classroom Model
- 2020
-
Ingår i: The 5th International Scientific and Practical Conference <em>Languages and Contemporary Problems of Education </em>[Язык и актуальные проблемы образования]. - Moscow, Russia : The International Academy of Pedagogical Educational Sciences and Moscow State Regional University. - 9785604341186 ; , s. 182-192
-
Konferensbidrag (refereegranskat)abstract
- Digitalization and multidisciplinary approach are the new trends in Teaching and Learning theory and practice. The article lays emphasis on mathematics teaching and learning knowledge, based on Action Research Theory, New Learning Theory and Variation Theory. Preservice early elementary school teachers created audiovisual video films (AV) and Podcasts (PD) lessons integrating Mathematics, Music and Language during a university course in teacher education. These multidisciplinary lessons were used as intelligent tutors in a flipped classroom model. The lessons are dealing with proportionality, one of the most difficult items in elementary school mathematical curriculum. For explaining proportionality, the preservice teachers have used multiple representations such as manipulatives, fiction stories, videogame Minecraft, “Smash up” in tennis table, musical intervals, self-composed, self-written and self-performed songs about mathematical rules in easy to remember rap-style. Preservice teachers have shown their AV or PD lessons to elementary school students followed by joint discussions and exercisers in solving of mathematical problems. Preservice teachers analyzed their work in an essay-form report describing creation of their intelligent tutors for elementary school students’ knowledge development in mathematics, music and language, including pronunciation, explanation and understanding of mathematical terminology. The multipart flipped classroom approach promoted prospective teachers’ professional growth. For future analysis the described multipart flipped classroom model can be further developed in international collaboration.
|
|
| 8. |
- Asghar, Naveed, et al.
(författare)
-
Deep sequencing analysis of tick-borne encephalitis virus from questing ticks at natural foci reveals similarities between quasispecies pools of the virus
- 2017
-
Ingår i: Journal of General Virology. - : The Microbiology Society. - 0022-1317 .- 1465-2099. ; 98:3, s. 413-421
-
Tidskriftsartikel (refereegranskat)abstract
- Every year, tick-borne encephalitis virus (TBEV) causes severe central nervous system infection in 10 000 to 15 000 people in Europe and Asia. TBEV is maintained in the environment by an enzootic cycle that requires a tick vector and a vertebrate host, and the adaptation of TBEV to vertebrate and invertebrate environments is essential for TBEV persistence in nature. This adaptation is facilitated by the error-prone nature of the virus's RNA-dependent RNA polymerase, which generates genetically distinct virus variants called quasispecies. TBEV shows a focal geographical distribution pattern where each focus represents a TBEV hotspot. Here, we sequenced and characterized two TBEV genomes, JP-296 and JP-554, from questing Ixodes ricinus ticks at a TBEV focus in central Sweden. Phylogenetic analysis showed geographical clustering among the newly sequenced strains and three previously sequenced Scandinavian strains, Toro-2003, Saringe-2009 and Mandal-2009, which originated from the same ancestor. Among these five Scandinavian TBEV strains, only Mandal-2009 showed a large deletion within the 3' non-coding region (NCR), similar to the highly virulent TBEV strain Hypr. Deep sequencing of JP-296, JP-554 and Mandal-2009 revealed significantly high quasispecies diversity for JP-296 and JP-554, with intact 3' NCRs, compared to the low diversity in Mandal-2009, with a truncated 3' NCR. Single-nucleotide polymorphism analysis showed that 40% of the single-nucleotide polymorphisms were common between quasispecies populations of JP-296 and JP-554, indicating a putative mechanism for how TBEV persists and is maintained within its natural foci.
|
|
| 9. |
- Asghar, Naveed, 1983-, et al.
(författare)
-
Local landscape effects on population dynamics of Ixodes ricinus
- 2016
-
Ingår i: Geospatial health. - : Page Press Publications. - 1827-1987 .- 1970-7096. ; 11:3, s. 283-289
-
Tidskriftsartikel (refereegranskat)abstract
- Ixodes ricinus, a common tick in Europe, transmits severe tickborne pathogens (TBPs). In Sweden, both prevalence and incidence of tick-borne infections have increased during the last few decades, and a majority of the cases is reported from the area around Stockholm. Among ticks, transmission of TBPs involves co-feeding of susceptible larvae or nymphs with infected ticks on the same host. Seasonal synchrony of immature stages and total tick abundance are important factors for the probability of horizontal transmission of TBPs. We have studied the association between local landscape characteristics and population dynamics and the probability of co-occurrence of different life cycle stages of I. ricinus at different locations south of Stockholm, Sweden. We found significant spatiotemporal variation in tick activity patterns. Mean tick abundance varied with a tenfold difference among study sites. The probability of co-occurrence of larvae, nymphs and female adults was highest in June and decreased significantly with vegetation height. In addition, the amount of forest habitat and open water in the surrounding landscape of the study sites expressed significant negative effects on tick abundance and co-occurrence, indicating that environmental heterogeneity may increase the likelihood of good rodent habitats, which in turn, are suitable hosts for immature ticks.
|
|
| 10. |
- Asghar, Naveed, 1983-
(författare)
-
Ticks and Tick-borne Encephalitis Virus : From Nature to Infection
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Vector-borne diseases are an increasing global threat to humans due to climate changes, elevating the risk of infections transmitted by mosquitos, ticks, and other arthropod vectors. Ixodes ricinus, a common tick in Europe, transmits dangerous tick-borne pathogens to humans. Tick-borne encephalitis (TBE) is a vector-borne disease caused by TBE virus (TBEV). Climate change has contributed to increased tick abundance and incidence of tick-borne diseases, and between 10,000 and 15,000 human TBE cases are reported annually in Europe and Asia. TBEV shows a patchy geographical distribution pattern where each patch represents a natural focus. In nature, TBEV is maintained within the tick-rodent enzootic cycle. Co-feeding is the main route for TBEV transmission from infected to uninfected ticks and for maintenance within the natural foci. The increasing number of TBE cases in Scandinavia highlights the importance of characterizing additional TBEV sequences and of identifying novel natural foci, and in this work we sequenced and phylogenetically characterized four TBEV strains: Saringe-2009 (from a blood-fed nymph), JP-296 (from a questing adult male), JP-554 (from a questing adult male), and Mandal-2009 (from a pool of questing nymphs, n = 10). Mandal-2009 represents a TBEV genome from a natural focus in southern Norway. Saringe-2009 is from a natural endemic focus in northern Stockholm, Sweden, and JP-296 and JP-554 originate from a natural focus “Torö” in southern Stockholm. In addition, we have studied the effect of different biotic and abiotic factors on population dynamics of I. ricinus in southern Stockholm and observed significant spatiotemporal variations in tick activity patterns. Seasonal synchrony of immature stages and total tick abundance are important factors for the probability of horizontal transmission of TBEV among co-feeding ticks. We found that the probability of co-occurrence of larvae, nymphs, and female adults was highest during early summer whereas increasing vegetation height and increasing amounts of forest and open water around the study sites had a significant negative effect on co-occurrence of larvae, nymphs, and female adults.The proximal part of the 3 ́non-coding region (3 ́NCR) of TBEV contains an internal poly(A) tract, and genomic analysis of Saringe-2009 revealed variability in the poly(A) tract indicating the existence of different variants within the TBEV pool of Saringe-2009. Like other RNA viruses, TBEV exists as swarms of unique variants called quasispecies. Because Saringe-2009 came from an engorged nymph that had been feeding on blood for >60 h, we propose that Saringe-2009 represents a putative shift in the TBEV pool when the virus switches from ectothermic/tick to endothermic/mammalian environments. We investigated the role of poly(A) tract variability in replication and virulence of TBEV by generating two infectious clones of the TBEV strain Toro-2003, one with a short/wild-type (A)3C(A)6 poly(A) tract and one with a long (A)3C(A)38 poly(A) tract. The infectious clone with the long poly(A) tract showed poor replication in cell culture but was more virulent in C57BL/6 mice than the wild-type clone. RNA folding predictions of the TBEV genomes suggested that insertion of a long poly(A) tract abolishes a stem loop structure at the beginning of the 3 ́NCR. Next generation sequencing (NGS) analysis of the TBEV genomes after passaging in cell culture and/or mouse brain revealed molecular determinants and quasispecies structure that might contribute to the observed differences in virulence. Our findings suggest that the long poly(A) tract imparts instability to the TBEV genome resulting in higher quasispecies diversity that in turn contributes to TBEV virulence. Phylogenetic analysis of Saringe-2009, JP-296, JP-554, and Mandal-2009 predicted a strong evolutionary relationship among the four strains. They clustered with Toro-2003, the first TBEV strain from Torö, demonstrating a Scandinavian clade. Except for the proximal part of the 3 ́NCR, TBEV is highly conserved in its genomic structure. Genomic analysis revealed that Mandal-2009 contains a truncated 3 ́NCR similar to the highly virulent strain Hypr, whereas JP-296 and JP-554 have a genomic organization identical to Toro-2003, the prototypic TBEV strain from the same natural focus. NGS revealed significantly higher quasispecies diversity for JP-296 and JP-554 compared to Mandal-2009. In addition, single nucleotide polymerphism (SNP) analysis showed that 40% of the SNPs were common between quasispecies populations of JP-296 and JP-554, indicating the persistence and maintenance of TBEV quasispecies within the natural focus.Taken together, these findings indicate the importance of environmental factors for the occurrence pattern of the different life-stages of the tick vector, which are important for the persistence of TBEV in nature. Our findings also show that the selection pressure exerted by specific host also affects the population structure of the TBEV quasispecies. In addition, our results further demonstrate that the evolution of quasispecies has effect on TBEV virulence in mice.
|
|
