| 1. |
- Kvarnström, Gun, 1951-
(författare)
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Visual screening of children in Sweden : epidemiological and methodological aspects
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to assess the vision screening system and ocular status in Sweden of today, yesterday and tomorrow and to compare the prevalence of ocular disease before and after screening and treatment with special focus on amblyopia.Screening has been defmed by the United States Commission of Chronic Illness (1957) as "the presumptive identification of unrecognized disease or defect by the application oftests, examinations or other procedures, which can be rapidly applied. Screening tests sort out apparently well persons who probably have a disease from those who probably do not". The screening system for eye disorders was introduced in the whole country in the beginning of 1970 and has not been evaluated in a greater area and for a longer period. Neither has an evaluation been done according to WHO's instructions. Amblyopia is the most common cause to visual impairment in one eye. The visual system is developing mostly in the first years of life and it is important to treat amblyopia in early childhood. The three first papers are retrospective studies and the fourth a prospective study. The study group in the first and second paper consisted of all children born 1982 in three Swedish cities from newborn until the age of 10 years. The children have been tested eight to nine times at the Child Health Care Centres and in school during this time. The sensitivity and specificity of visual screening were 92% and 97% respectively. The prevalence of ametropia was 7.7%, strabismus 3.1%, amblyopia ≤ 7 2.9% and organic lesions 0.2%. We compared the prevalence of amblyopia today with the time before screening was introduced in Sweden. This comparison shows that serious amblyopia has been reduced about 10 times with screening and treatment.Loss of vision in the non-amblyopic eye was investigated by studying patients with amblyopia at four visual rehabilitation centres. Approximately 1.2% of the people with amblyopia ≤ 0.3 will eventually become visually handicapped due to lesions in the better eye.Despite visual screening and treatment there are some children left with residual amblyopia. We investigated ways to improve the system by lowering the age for visual acuity examination from 4 to 3 years and at the same time two vision charts were compared. We found that the testability rate for 3-year-olds was almost the same for the Lea Symbol chart and the HVOT chart (82.8% and 84.8% respectively). Testability was about 10% higher at 4 years. The positive predictive value was lower at 3 years (58%) than has previously been found at 4 years (72%).Conclusion: In these studies we have found that screening is justified for the following reasons: visual screening is efficient in terms of sensitivity and specificity and many important ocular conditions are detected in this process; the prevalence of serious amblyopia is greatly reduced by screening and treatment; loss of vision in the non-amblyopic eye is a significant problem, which can be greatly reduced by screening and treatment, thereby saving expenses for the society.The following has been found regarding the design of visual screening: visual acuity testing is efficient in detecting visual disorders from 4 years and up; visual acuity can be tested at 3 years, but with lower positive predictive value; the most widely used charts in Sweden and internationally, the HVOT chart and the Lea Symbols chart perform equally well in visual acuity testing of 3-year-old and 4-year-old children.
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| 2. |
- Fraser, Magdalena
(författare)
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People of the Dolmens and Stone Cists : An archaeogenetic Investigation of Megalithic Graves from the Neolithic Period on Gotland
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The study of ancient genomics of pre-historic human remains has in recent years offered unprecedented knowledge regarding pre-historic migration and population structure on the European continent which has fundamentally altered the current views in the archaeological community. However, the merging of the two fields, archaeology and genetics, is still in its infancy and much work is still needed in order for these fields to integrate. In this thesis I explore how genetic analyses, in combination with contextual radiocarbon dating and isotopic analyses for diet and mobility can be used to investigate demographic events on a local and regional level. This is done through the investigation of people buried in five previously excavated megalithic tombs on the Island of Gotland dated to the Neolithic period. I present the genomic population structure and archaeological background for the pre-historic European reference data and show how this is used to investigate population continuity, demographic shifts, cultural duality, and admixture for local and regional contexts. I present new data and explore the Strontium-baseline for the Gotland biosphere which is used for the mobility analyses. I show that mitochondrial haplogroup data is especially useful in combination with isotopic data, and radiocarbon dating for investigation of demographic shifts on a larger scale. I also show that genomic data gives unique insights into the individuals’ life history which, together with the established demographic background allows for fine scale investigation of population demographic events within and between different archaeological contexts. Finally I show that the different Neolithic contexts on Gotland to a large extent involves immigration of new groups to the island, and that the contextual breaks seen in the archaeological record during the Neolithic period are connected with cultural and population demographic shifts. This dissertation demonstrates that genomic analyses, in combination with archaeology and isotopic analyses, as well as contextual osteological analyses and radiocarbon dating, present unique insights into the life history of the actual people who lived the lives we try to understand.
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| 3. |
- Gustafsson, Barbro, 1954-
(författare)
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Undersökningar av sociovetenskapliga samtal i naturvetenskaplig utbildning
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis examines the potential of students’ group discussions in science education in the context of a communicative perspective on democracy and meaning-making. The group discussions in focus are about socioscientific issues (SSI), i.e. controversial and complex issues with scientific as well as sociological aspects. The philosophical works of John Dewey and Jürgen Habermas serve as the main theoretical underpinnings. Different types of empirical data were used for the qualitative analyses: policy documents, student teachers’ essays, student interviews and recorded group discussions between classmates.Attention is drawn to the twofold educational mission to ensure students’ subject knowledge and democratic growth, where the democracy aspect of this mission is in danger of being given secondary priority in science education. Deliberations about SSI are suggested as a possible way of bridging the gap between the two tasks. An ideal deliberation is characterised by democratic virtues such as sincerity, consideration, a critical review of what is otherwise taken for granted and an aspiration to seek agreement. SSIs facilitate theoretical, ethical and moral reflection and examine argumentation skills in a reflective and considerate way in order to lead to participation and the creation of meaning in mutual communication.Both the possibilities and shortcomings of deliberative-oriented group conversations were highlighted in the interviews with upper secondary school students involved in the socioscientific tasks. This then provided guidance for an extended study of SSI-deliberations among students, also from upper secondary school. An analysis tool, DEQUAL, was constructed in order to be in a position to assess their democratic and deliberative qualities.The overall results showed that students could maintain respectful and engaged conversations in which they jointly created and developed arguments. However, expressions of meaning-making in terms of insights and new-found experiences were scarce. Furthermore, the students seemed too eager to agree. Although the guidelines emphasised the importance of advancing various arguments, other students’ statements were rarely challenged. If SSI-conversations are to approach democratic and deliberative ideals and stimulate meaning-making, the participants must be prepared to exchange contrasting views. According to Habermas’ theory, when deliberating one relates to a subjective world of experiences, a social world of common agreements and an objective world of facts. Since both science and SSI contribute objective, factual dimensions, it is suggested that the deliberative idea might have a particular bearing on science education, since the conversations do not just revolve around personal opinions.It was concluded that the development of deliberative conversation skills requires careful, guided practice. It also became clear that the deliberative guidelines for seeking agreement and the teacher’s non-participation in the talks needed to be reviewed.
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| 4. |
- Herman, Stephanie, et al.
(författare)
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Integration of magnetic resonance imaging and protein and metabolite CSF measurements to enable early diagnosis of secondary progressive multiple sclerosis
- 2018
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Ingår i: Theranostics. - : Ivyspring International Publisher. - 1838-7640. ; 8:16, s. 4477-4490
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Tidskriftsartikel (refereegranskat)abstract
- Molecular networks in neurological diseases are complex. Despite this fact, contemporary biomarkers are in most cases interpreted in isolation, leading to a significant loss of information and power. We present an analytical approach to scrutinize and combine information from biomarkers originating from multiple sources with the aim of discovering a condensed set of biomarkers that in combination could distinguish the progressive degenerative phenotype of multiple sclerosis (SPMS) from the relapsing-remitting phenotype (RRMS). Methods: Clinical and magnetic resonance imaging (MRI) data were integrated with data from protein and metabolite measurements of cerebrospinal fluid, and a method was developed to sift through all the variables to establish a small set of highly informative measurements. This prospective study included 16 SPMS patients, 30 RRMS patients and 10 controls. Protein concentrations were quantitated with multiplexed fluorescent bead-based immunoassays and ELISA. The metabolome was recorded using liquid chromatography-mass spectrometry. Clinical follow-up data of the SPMS patients were used to assess disease progression and development of disability. Results: Eleven variables were in combination able to distinguish SPMS from RRMS patients with high confidence superior to any single measurement. The identified variables consisted of three MRI variables: the size of the spinal cord and the third ventricle and the total number of T1 hypointense lesions; six proteins: galectin-9, monocyte chemoattractant protein-1 (MCP-1), transforming growth factor alpha (TGF-alpha), tumor necrosis factor alpha (TNF-alpha), soluble CD40L (sCD40L) and platelet-derived growth factor AA (PDGF-AA); and two metabolites: 20 beta-dihydrocortisol (20 beta-DHF) and indolepyruvate. The proteins myelin basic protein (MBP) and macrophage-derived chemokine (MDC), as well as the metabolites 20 beta-DHF and 5,6-dihydroxyprostaglandin F1a (5,6-DH-PGF1), were identified as potential biomarkers of disability progression. Conclusion: Our study demonstrates, in a limited but well-defined and data-rich cohort, the importance and value of combining multiple biomarkers to aid diagnostics and track disease progression.
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| 5. |
- Johansson, Björn
(författare)
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A Study of Some Temporal Properties of the Human Visual Evoked Potential, and Their Relation to Binocular Function
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As disturbed binocular functions in small children may lead to severe amblyopia it is of interest to detect it as early as possible. Most tests for binocular functions, however, demand active cooperation and may be unreliable in children up to 4-5 years of age. This study therefore aims to employ visual evoked potentials (VEP) to enable the examiner to evaluate the binocular function in a subject without need of active cooperation from the subject.Initially we studied the relation of suprathreshold contrast to the latency of the transient pattern VEP (tpVEP). Although suprathreshold contrast independently influenced the tpVEP latency, interindividual variation was too large to suggest tpVEP as a possible method for objectively measuring contrast sensitivity in a subject.The tpVEP latency in normal and microstrabismic adult subjects was examined. It was significantly shorter with binocular viewing in normals, but not in the microstrabismic group.Contrast sensitivity and tpVEP latency was examined in adults, both with normal binocularity and with microstrabismus, using both luminance (black-and-white) contrast and colour contrast patterns. The tpVEP latency to colour contrast, like that to luminance contrast, is shorter in normal subjects who view the stimulus binocularly. Interindividual variation or overlap between the normal and microstrabismic groups did not improve with colour contrast.The most significant features of the tpVEP are amplitude and latency. Depending on stimulus conditions, the response may show variations in configuration, amplitude and, to a lesser degree, latency. To decrease the influence of such variations steady-state VEP (ssVEP) can be used. The stimulus is presented in a fast repetitive manner, yielding a VEP response shaped as a continuous curve. The frequency components of this curve can be analysed using Fast Fourier Analysis.Fast Fourier analysis of ssVEP in children aged 8-15 years with normal binocularity and with microstrabismus showed that the power of the second harmonic (the double frequency of stimulus frequency) of the response with binocular viewing was larger than with monocular viewing, both in normals and microstrabismic subjects. For higher stimulus frequencies, microstrabismic subjects showed a significantly lower power of the second harmonic compared with subjects with normal binocularity, when the stimulus was presented binocularly.Finally, Fast Fourier analysed ssVEP in pre-school children aged 4-5 years was studied. A normal group was compared with a group with microstrabismus and a group with significant amblyopia. Amblyopic subjects had significant interocular differences in the first harmonic. We confirmed the significant difference found between microstrabismic subjects and subjects with normal binocularity regarding the second harmonic’s power with higher temporal frequency binocular stimulation, although at a slightly lower frequency than for older children. A low power of the second harmonic in the ssVEP to a binocular stimulus with high temporal frequency is a strong indicator of disturbed binocular function.
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| 6. |
- Lidar, Malena, 1973-
(författare)
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Erfarenhet och sociokulturella resurser : Analyser av elevers lärande i naturorienterande undervisning
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contributes to the knowledge about the role of sociocultural resources in students’ learning in Science Education. In the analyses, both individual experiences and situation are taken into account. Different sociocultural resources – the teacher, artefacts and texts – that students encounter in educational settings are focused with the aim to study what role they play for which meaning making is made possible and relevant. To study these encounters, a pragmatist approach called practical epistemology analysis – i.e. an analysis of what students use as relevant information, valid questions and relevant attentiveness – is used and advanced. The empirical material consists of video recordings from Science Education classrooms in Swedish compulsory school. The first paper is an introduction to the line of work subsequently performed. In the second paper, a method for analysing the role of teaching for students’ meaning making – epistemological moves analysis – is developed and illustrated. This method focuses on those actions of the teacher that have a function of influencing what direction students’ learning takes. In the third paper, the practical epistemology approach is applied in order to clarify, within a sociocultural understanding of learning, the role of the interplay between students’ prior experiences and the use of artefacts in students’ meaning making. In the fourth paper, the practical epistemology approach is applied as a method for investigating the role of instructional texts in laboratory settings for students’ meaning making. The thesis shows how individual continuity can be understood and analysed within a sociocultural perspective on learning. The developed methods make it possible to study learning as constituted in action without ascribing teachers, artefacts or texts a pre-determined meaning prior to their use in a practice. The results show that the way sociocultural resources are made intelligible by the students shapes the conditions for further meaning making.
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| 7. |
- Lindahl, Camilla, 1969-
(författare)
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Tecken av betydelse : En studie av dialog i ett multimodalt, teckenspråkigt tvåspråkigt NO-klassrum.
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ett gemensamt meningsskapande i skolans naturvetenskapliga klassrum förutsätter en interaktion som i allt högre grad kommer att präglas av ett naturvetenskapligt språkbruk. Utvecklingen av ett naturvetenskapligt ämnesspråk innebär ofta en stor utmaning för flerspråkiga elever som lär sig naturvetenskap på sitt andraspråk och vars behov av stöttning därför är särskilt stort. Denna studie utforskar döva och hörselskadade elevers lärande naturvetenskap i ett tvåspråkigt NO-klassrum där meningsskapandet sker genom svenskt teckenspråk och skriven svenska. Avhandlingens övergripande frågor är hur svenskt teckenspråk och svenska används i dialogen och hur dessa språk, i interaktion med andra modaliteter, bidrar till meningsskapandet i naturvetenskap. En grupp på två lärare och åtta elever, alla döva och teckenspråkig tvåspråkiga, filmades i totalt sjutton NO-lektioner. Klassrumskommunikation i denna teckenspråkigt tvåspråkiga miljö med naturvetenskapliga artefakter som modeller, tabeller och övrig naturvetenskaplig utrustning analyseras sedan från ett multimodalt socialsemiotiskt perspektiv där språk och modaliteter diskuteras som potentiella resurser i meningsskapandet. Resultaten visar en komplex dialog där språk och modaliteter hela tiden växlar på ett sätt som starkt bidrar till att driva dialogen framåt. Vidare framstår det visuella-gestuella teckenspråket som en kraftfull modalitet. I synnerhet spelar avbildande tecken en framträdande roll i dialogen och i det naturvetenskapliga meningsskapandet. Språkväxlingar i den teckenspråkiga dialogen sker dynamiskt i form av sömlösa och spontana växlingar men utnyttjas även som pedagogiskt verktyg. Teckenspråkets kontextbundenhet kräver dessutom ibland tvärspråkliga resonemang på metanivå där oklarheter såväl som likheter och skillnader mellan olika språkliga uttryck kan redas ut. Resultaten uppmärksammar också lärarnas viktiga roll för att stötta eleverna i det naturvetenskapliga meningsskapandet liksom för utvecklingen av ett naturvetenskapligt språk. I diskussionen lyfts behovet av pedagogiska strategier som stärker stöttningen av döva och hörselskadade elevers teckenspråkiga tvåspråkiga meningsskapande i naturvetenskap.
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