| 1. |
- Brunström, Mats, 1960-
(författare)
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Matematiska resonemang i en lärandemiljö med dynamiska matematikprogram
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall problem that formed the basis for this thesis is that students get limited opportunity to develop their mathematical reasoning ability while, at the same time, there are dynamic mathematics software available which can be used to foster this ability. The aim of this thesis is to contribute to knowledge in this area by focusing on task design in a dynamic software environment and by studying the reasoning that emerges when students work on tasks in such an environment. To analyze students’ mathematical reasoning, a new analytical tool was developed in the form of an expanded version of Toulmin’s model.Results from one of the studies in this thesis show that exploratory tasks in a dynamic software environment can promote mathematical reasoning in which claims are formulated, examined and refined in a cyclic process. However, this reasoning often displayed a lack of the more conceptual, analytic and explanatory reasoning normally associated with mathematics. This result was partly confirmed by another of the studies. Hence, one key question in the thesis has been how to design tasks that promote conceptual and explanatory reasoning. Two articles in the thesis deal with task design. One of them suggests a model for task design with a focus on exploration, explanation, and generalization. This model aims, first, to promote semantic proof production and then, after the proof has been constructed, to encourage further generalizations. The other article dealing with task design concerns the design of prediction tasks to foster student reasoning about exponential functions. The research process pinpointed key didactical variables that proved crucial in designing these tasks.
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| 2. |
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| 3. |
- Engström, Arne, Docent, 1953-
(författare)
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Betydelsen av att klara matematiken i skolan
- 2017
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Ingår i: Skolhälsan. - : Riksföreningen för skolsköterskor. - 0284-284X. ; :4, s. 18-19
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 4. |
- Engström, Arne, Docent, 1953-
(författare)
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Elever med mycket låga prestationer i matematik : En pilotstudie av ämnesprovet i årskurs 3
- 2017
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Rapport (refereegranskat)abstract
- Låga prestationer i matematik är en av de europeiska utbildningssystemens stora utmaningar. Det råder stor samstämmighet om vikten av tidig upptäckt och insats för elever som är i riskzonen för att utveckla skolsvårigheter. Ett medel för detta är de nationella proven i matematik. I föreliggande rapport redogörs för en pilotstudie av elever med mycket låga prestationer på ämnesprovet i matematik för årskurs 3 i en utvald kommun. Elevernas resultat på ämnesprovet, könsskillnader samt förekomst av särskilt stöd inventeras i studien. Resultatet pekar på att situationen för elever som tidigt uppvisar mycket låga prestationer behöver uppmärksammas. De riskerar att misslyckas med att utveckla grundläggande färdigheter i skolan till en tillfredsställande nivå. Samtidigt reser studien också frågan om alla elever har förutsättningar att nå grundskolans kravnivå.
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| 5. |
- Engström, Arne, Docent, 1953-
(författare)
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Från dyskalkyli till låga prestationer i matematik : Arvet efter Olof Magne
- 2016
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Rapport (refereegranskat)abstract
- Matematiksvårigheter eller låga prestationer i matematik är en av de stora utmaningar som de europeiska utbildningssystemen står inför idag. Att misslyckas med skolmatematiken får stora konsekvenser för både elever och samhället.Den som kanske mer än någon annan kommit att personifiera den svenska forskningen om matematiksvårigheter är Olof Magne. Under 1950-talet arbetade han med de så kallade Göteborgsundersökningarna som omfattade 6000 folkskoleelever. Dessa följdes sedan upp av en serie interventionsstudier under 1960-talet riktade mot räknesvaga elever. Därefter påbörjade han arbetet med en kognitiv taxonomi för den elementära matematikundervisningen.De hypoteser som Magne ställde i Göteborgsundersökningarna följdes upp i det stora Medelsta-projektet. Här kan man följa utvecklingen av grundskolelevers matematikkunskaper under en period av 25 år. Den första studien i projektet gjordes 1977 och replikerades sedan vid två tillfällen 1986 och 2002.Syftet med föreliggande rapport är att beskriva och analysera Olof Magnes forskning inom området låga prestationer i matematik – vilka var frågorna, metoderna och resultatet samt var står vi idag? De frågor som restes i Magnes inledande studier för mer än 60 år sedan fortsätter att sysselsätta oss än idag.
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| 6. |
- Engström, Arne, Docent, 1953-
(författare)
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Semiotiska perspektiv i matematikdidaktik : En introduktion
- 2018
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Rapport (refereegranskat)abstract
- Semiotiska perspektiv i matematikdidaktik har fått en ökad uppmärksamhet under senare år. I flera länder finns en livaktig forskning på området. I Sverige är semiotiska perspektiv inom matematikdidaktiken ännu svagt utvecklad. Föreliggande rapport syftar till att introducera semiotiska perspektiv inom den matematikdidaktiska forskningen. Teoretiskt inspireras dessa perspektiv av Ferdinand de Saussures och Charles S. Peirce arbeten.Människor uttrycker matematiska tankar med hjälp av tecken av olika slag. Ett tecken står för någonting. Detta någonting är i matematik ett matematiskt objekt. Matematik kan uppfattas som en generalisering av tecken eller representationssystem. En väsentlig del av den moderna matematiken handlar om symbolisering. Det är inte främst en abstraktion av den direkta verkligheten, utan om en kedja av abstraktioner. Ett matematiskt objekt eller sakförhållande kan bara förstås och kommuniceras när det representeras och tolkas i någon form. Spänningsfältet mellan sakförhållandet, representationen och tolkningen gör därför semiotiska perspektiv mycket intressanta för matematikdidaktisk forskning.
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| 7. |
- Engström, Arne, 1953-
(författare)
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Specialpedagogiska frågeställningar i matematik
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Låga prestationer i matematik är en av de stora utmaningar som de europeiska utbildningssystemen står inför. Det är en fråga som inte bara handlar om undervisningens effektivitet utan också om att skapa ett rättvist utbildningssystem. Alla moderna utbildningssystem står inför ett antal grundläggande motsättningar, eller dilemman, som i egentlig mening inte kan lösas, men likväl måste hanteras. I en skola för alla är elevernas olikheter ett grundläggande dilemma. Den gamla skolans sätt att hantera olikheterna, genom särskiljning och segregerande lösningar, har vi lämnat bakom oss. De nya utmaningar som utbildningssystemet står inför måste hanteras på andra sätt.I rapporten introduceras några specialpedagogiska frågeställningar i matematik. Matematiken fungerar som ett kritiskt filter och systemindikator för ett skolsystem. Att misslyckas i matematik får ofta större och vidare konsekvenser än att misslyckas i andra ämnen. Låga prestationer betraktas i rapporten som ett socialt problemfält. Rapporten vänder sig såväl till lärarstuderande som till verksamma lärare, som önskar en lättillgänglig introduktion till frågeställningar som lärare i matematik, speciallärare eller specialpedagoger behöver orientera sig om och ta ställning till i sin yrkesutövning.
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| 8. |
- Fahlgren, Maria, 1966-
(författare)
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Designing for the integration of dynamic software environments in the teaching of mathematics
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerns the challenge of integrating dynamic software environments into the teaching of mathematics. It investigates particular aspects of the design of tasks which employ this type of computer-based system, with a focus on improvement, both of the tasks themselves and of the design process through which they are developed and refined.The thesis reports two research projects: a small initial one preceding a larger main project. The initial case study, involving two graduate students in mathematics, develops a task design model for geometrical locus problems. The main study constitutes the first iteration of a design-based study, conducted in collaboration with four upper-secondary school teachers and their classes. It seeks to identify task design characteristics that foster students’ mathematical reasoning and proficient use of software tools, and examines teachers’ organisation of ‘follow-up’ lessons.The findings concern three particular aspects: features of tasks and task environment relevant to developing a specific plan of action for a lesson; orchestration of a particular task environment to support the instrumental genesis of specific dynamic software tools; how to follow up students’ work on computer-based tasks in a whole-class discussion.
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| 9. |
- Fava, Cristiano, et al.
(författare)
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A genetic risk score for hypertension associates with the risk of ischemic stroke in a Swedish case-control study
- 2015
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Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 23, s. 969-974
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Tidskriftsartikel (refereegranskat)abstract
- Genetic risk scores (GRS), summing up the total effect of several single-nucleotide polymorphisms (SNPs) in genes associated with either coronary risk or cardiovascular risk factors, have been tested for association with ischemic stroke with conflicting results. Recently an association was found between a GRS based on 29 SNPs discovered by genome-wide association studies and hypertension. The aim of our study was to investigate the possible association of the same GRS with ischemic stroke on top of other ‘traditional risk factors’, also testing its potential improvement in indices of discrimination and reclassification, in a Swedish case–control study. Twenty-nine SNPs were genotyped in 3677 stroke cases and 2415 controls included in the Lund Stroke Register (LSR), the Malmö Diet and Cancer (MDC) study and the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). The analysis was conducted in the combined sample, and separately for the three studies. After adjustment for hypertension, diabetes mellitus and smoking habits, the GRS was associated with ischemic stroke in the combined sample (OR (95% CI) 1.086 (1.029–1.147) per SD increase in the GRS P=0.003) with similar trends in all three samples: LSR (1.050 (0.967–1.140); P=0.25), MDC (1.168 (1.060–1.288); P=0.002) and SAHLSIS (1.124 (0.997–1.267); P=0.055). Measures of risk discrimination and reclassification improved marginally using the GRS. A blood pressure GRS is independently associated with ischemic stroke risk in three Swedish case–control studies, however, the effect size is low and adds marginally to prediction of stroke on top of traditional risk factors including hypertension.
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| 10. |
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| 11. |
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| 12. |
- Olteanu, Lucian, 1956-
(författare)
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Framgångsrik kommunikation i matematikklassrummet
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The research for this thesis was done to examine, describe and understand the ways in which mathematical content (algebra) is communicated in classrooms. It also sought to identify the opportunities that allow successful classroom communication.The educational design research approach in this study was used to understand the connection between teaching, communication and students' learning. The empirical material consisted of video-recorded lessons, observations, students’ tests and teachers’ written reports of the instructions for lessons. The empirical material was analysed using concepts relating to variation theory, strong compositionality and research results found in mathematics education.Some important findings have been found in this thesis. Communicative success is linked to a hierarchic structure of communicative events with a strong compositionality. It is also linked to the discernment of the structure of algebraic objects. This structure is a relation between para- and proto-mathematical concepts and a form of composition with a semantic character. Teachers support successful classroom communication by using research results found in mathematics education to open up patterns of variation in the critical aspects of an object of learning. Similarity is a pattern identified in this study, and it is defined as the property of two or more expressions to adapt the same meaning. Teachers also support successful classroom communication through a systematic analysis of the parts of an object of learning, relations between parts, how to relate the parts to each other in different ways, the relation between the parts, the relation between the parts and the whole as well as the relation between different wholes. Through and around tasks, teachers and students are communicating successfully or not according to the opportunities provided in the classroom to work out the meaning of the whole by understanding the meaning of the simple parts, the semantic significance of a finite number of syntactic modes of composition, and by recognizing how the whole is made up out of simple parts. If the choice/construction of tasks is focused on what may vary and what stays invariant, students' opportunities to distinguish aspects that could lead to algebraic generalizations are improved. One of the values of this study is in the design of the project that contributes to integration of research results found in mathematics education, in teachers' practice. In addition, a value of the study lies in its operational definition of the concept of communication, which can be used to study successful communication. Communication is a collectively performed patterned activity in which an aspect that is critical for one or more students (A) is focused on by the action of the teacher or other students (B) so that A discerns the aspects focused on by B.
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| 13. |
- Pulit, SL, et al.
(författare)
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Loci associated with ischaemic stroke and its subtypes (SiGN): a genome-wide association study.
- 2016
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Ingår i: The Lancet. Neurology. - 1474-4465. ; 15:2, s. 174-84
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Tidskriftsartikel (refereegranskat)abstract
- The discovery of disease-associated loci through genome-wide association studies (GWAS) is the leading genetic approach to the identification of novel biological pathways underlying diseases in humans. Until recently, GWAS in ischaemic stroke have been limited by small sample sizes and have yielded few loci associated with ischaemic stroke. We did a large-scale GWAS to identify additional susceptibility genes for stroke and its subtypes.To identify genetic loci associated with ischaemic stroke, we did a two-stage GWAS. In the first stage, we included 16851 cases with state-of-the-art phenotyping data and 32473 stroke-free controls. Cases were aged 16 to 104 years, recruited between 1989 and 2012, and subtypes of ischaemic stroke were recorded by centrally trained and certified investigators who used the web-based protocol, Causative Classification of Stroke (CCS). We constructed case-control strata by identifying samples that were genotyped on nearly identical arrays and were of similar genetic ancestral background. We cleaned and imputed data by use of dense imputation reference panels generated from whole-genome sequence data. We did genome-wide testing to identify stroke-associated loci within each stratum for each available phenotype, and we combined summary-level results using inverse variance-weighted fixed-effects meta-analysis. In the second stage, we did in-silico lookups of 1372 single nucleotide polymorphisms identified from the first stage GWAS in 20941 cases and 364736 unique stroke-free controls. The ischaemic stroke subtypes of these cases had previously been established with the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system, in accordance with local standards. Results from the two stages were then jointly analysed in a final meta-analysis.We identified a novel locus (G allele at rs12122341) at 1p13.2 near TSPAN2 that was associated with large artery atherosclerosis-related stroke (first stage odds ratio [OR] 1·21, 95% CI 1·13-1·30, p=4·50×10(-8); joint OR 1·19, 1·12-1·26, p=1·30×10(-9)). Our results also supported robust associations with ischaemic stroke for four other loci that have been reported in previous studies, including PITX2 (first stage OR 1·39, 1·29-1·49, p=3·26×10(-19); joint OR 1·37, 1·30-1·45, p=2·79×10(-32)) and ZFHX3 (first stage OR 1·19, 1·11-1·27, p=2·93×10(-7); joint OR 1·17, 1·11-1·23, p=2·29×10(-10)) for cardioembolic stroke, and HDAC9 (first stage OR 1·29, 1·18-1·42, p=3·50×10(-8); joint OR 1·24, 1·15-1·33, p=4·52×10(-9)) for large artery atherosclerosis stroke. The 12q24 locus near ALDH2, which has previously been associated with all ischaemic stroke but not with any specific subtype, exceeded genome-wide significance in the meta-analysis of small artery stroke (first stage OR 1·20, 1·12-1·28, p=6·82×10(-8); joint OR 1·17, 1·11-1·23, p=2·92×10(-9)). Other loci associated with stroke in previous studies, including NINJ2, were not confirmed.Our results suggest that all ischaemic stroke-related loci previously implicated by GWAS are subtype specific. We identified a novel gene associated with large artery atherosclerosis stroke susceptibility. Follow-up studies will be necessary to establish whether the locus near TSPAN2 can be a target for a novel therapeutic approach to stroke prevention. In view of the subtype-specificity of the associations detected, the rich phenotyping data available in the Stroke Genetics Network (SiGN) are likely to be crucial for further genetic discoveries related to ischaemic stroke.US National Institute of Neurological Disorders and Stroke, National Institutes of Health.
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| 14. |
- Stamm, Arne, et al.
(författare)
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Chemo- enzymatic pathways toward pinene- based renewable materials
- 2019
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Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 21:10, s. 2720-2731
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Tidskriftsartikel (refereegranskat)abstract
- Sobrerol methacrylate (SobMA) was synthesized and subsequently polymerized using different chemical and enzymatic routes. Sobrerol was enzymatically converted from -pinene in a small model scale by a Cytochrome P450 mutant from Bacillus megaterium. Conversion of sobrerol into SobMA was performed using both classical ester synthesis, i.e., acid chloride-reactions in organic solvents, and a more green approach, the benign lipase catalysis. Sobrerol was successfully esterified, leaving the tertiary alcohol and ene to be used for further chemistry. SobMA was polymerized into PSobMA using different radical polymerization techniques, including free radical (FR), controlled procedures (Reversible Addition Fragmentation chain-Transfer polymerization, (RAFT) and Atom Transfer Radical Polymerization (ATRP)) as well as by enzyme catalysis (horseradish peroxidase-mediated free radical polymerization). The resulting polymers showed high glass-transition temperatures (T-g) around 150 degrees C, and a thermal degradation onset above 200 degrees C. It was demonstrated that the T-g could be tailored by copolymerizing SobMa with appropriate methacrylate monomers and that the Flory-Fox equation could be used to predict the T-g. The versatility of PSobMA was further demonstrated by forming crosslinked thin films, either using the ene'-functionality for photochemically initiated thiol-ene'-chemistry, or reacting the tertiary hydroxyl-group with hexamethoxymethylmelamine, as readily used for thermally curing coatings systems.
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| 15. |
- Söderholm, M, et al.
(författare)
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Exome array analysis of ischaemic stroke : results from a southern Swedish study
- 2016
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Ingår i: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 23:12, s. 1722-1728
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Genome-wide association (GWA) studies have identified a few risk loci for ischaemic stroke, but these variants explain only a small part of the genetic contribution to the disease. Coding variants associated with amino acid substitutions or premature termination of protein synthesis could have a large effect on disease risk. We performed an exome array analysis for ischaemic stroke.METHODS: Patients with ischaemic stroke (n = 2385) and control subjects (n = 6077) from three Swedish studies were genotyped with the Illumina HumanOmniExpressExome BeadChip. Single-variant association analysis and gene-based tests were performed of exome variants with minor allele frequency of < 5%. A separate GWA analysis was also performed, based on 700 000 genotyped common markers and subsequent imputation.RESULTS: No exome variant or gene was significantly associated with all ischaemic stroke after Bonferroni correction (all P > 1.8 × 10(-6) for single-variant and >4.15 × 10(-6) for gene-based analysis). The strongest association in single-variant analysis was found for a missense variant in the DNAH11 gene (rs143362381; P = 5.01 × 10(-6) ). In gene-based tests, the strongest association was for the ZBTB20 gene (P = 7.9 × 10(-5) ). The GWA analysis showed that the sample was homogenous (median genomic inflation factor = 1.006). No genome-wide significant association with overall ischaemic stroke risk was found. However, previously reported associations for the PITX2 and ZFHX3 gene loci with cardioembolic stroke subtype were replicated (P = 7 × 10(-15) and 6 × 10(-3) ).CONCLUSIONS: This exome array analysis did not identify any single variants or genes reaching the pre-defined significance level for association with ischaemic stroke. Further studies on exome variants should be performed in even larger, well-defined and subtyped samples.
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| 16. |
- Söderholm, Martin, et al.
(författare)
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Incidence of stroke and stroke subtypes in chronic obstructive pulmonary disease.
- 2016
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Ingår i: European Journal of Epidemiology. - : Springer Science and Business Media LLC. - 1573-7284 .- 0393-2990. ; 31:2, s. 159-168
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Tidskriftsartikel (refereegranskat)abstract
- It is uncertain whether the incidence of stroke is increased in patients with chronic obstructive pulmonary disease (COPD), and whether COPD is associated with all subtypes of stroke (i.e. ischemic stroke, intracerebral haemorrhage and subarachnoid haemorrhage). We evaluated the association between COPD and incidence of stroke in a nation-wide cohort study. All individuals between 40 and 84 years of age, hospitalised for COPD between 1987 and 2003 in Sweden were identified in the Swedish hospital discharge register. For each COPD patient (n = 103,419), one reference individual was randomly selected from the general population matched for year of birth, sex and county of residence. After excluding subjects with prior stroke, incidence rates during 10 years follow-up were calculated. Hazard ratios (HR) for stroke comparing COPD patients with reference subjects were estimated using Cox regression adjusting for demographics and comorbidities. Incidence of all-cause stroke (n events = 17,402) was significantly increased in COPD patients compared to reference individuals (HR 1.24, 95 % CI 1.19-1.28), especially during the first 2 years after COPD diagnosis (HR 1.46, 1.37-1.55). Incidences of ischemic stroke (HR 1.20, 1.15-1.25), intracerebral haemorrhage (HR 1.29, 1.16-1.43) and subarachnoid haemorrhage (HR 1.46, 1.16-1.85) were all increased in COPD patients. Incidences of all stroke subtypes are increased in COPD, especially during the first years after COPD diagnosis. The association was independent of several comorbidities, although residual confounding from smoking and hypertension cannot be excluded. A global evaluation of stroke risk factors seems warranted in patients with COPD.
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| 17. |
- van Bommel, Jorryt, 1974-, et al.
(författare)
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Capturing, Managing and Analyzing Teachers' Informal Professional Development on Social Media
- 2018
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Rapport (refereegranskat)abstract
- Teachers’ professional discussions have now expanded onto different platforms on social media. Collecting such digital open accessible data from social media brings new challenges for educational researchers. Teachers’ discussions on Facebook are the focus of this study and the methodological issues coming from capturing, managing and analyzing our data are explored.Different social media generate different types of data and the difference between dialogical and monological communication becomes clear. Further, the issue of anonymity requires special attention, as one has to redefine what can be considered public information. As the data is relatively easy to gather, it can result in large quantities and a stratified sample of the data is suggested, both for qualitative and generalizable results.This report aims to convey our findings but also raises some unresolved questions, for instance concerning the use of different modalities or future technological development.
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