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| 2. |
- Wang, Zhaoming, et al.
(författare)
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Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33
- 2014
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:24, s. 6616-6633
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10(-39); Region 3: rs2853677, P = 3.30 × 10(-36) and PConditional = 2.36 × 10(-8); Region 4: rs2736098, P = 3.87 × 10(-12) and PConditional = 5.19 × 10(-6), Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10(-6); and Region 6: rs10069690, P = 7.49 × 10(-15) and PConditional = 5.35 × 10(-7)) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10(-18) and PConditional = 7.06 × 10(-16)). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci.
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| 3. |
- Ahrné, Karin, et al.
(författare)
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Dagfjärilar i naturbetesmarker, kraftledningsgator, på hyggen och skogsbilvägar : betydelse för miljöövervakning
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ett förändrat och intensifierat jordbruk har bland annat lett till att naturbetesmarker och andra gräsmarksbiotoper minskat i odlingslandskapet. Detta har fått till följd att många arter knutna till öppna gräsmarker minskat, däribland fåglar, växter och dagfjärilar. Dagfjärilar svarar snabbt på förändringar både i miljön och klimatet och kan därför vara viktiga indikatorarter för miljöövervakning. I år startar en nationell övervakning av dagfjärilar med hjälp av volontärer och de senaste fem åren har dagfjärilar inventerats i ängs- och betesmarker inom den nationella inventeringen av landskapet (NILS). För att få en rättvisande bild av hur situationen ser ut för dagfjärilar i Sverige kan det vara viktigt att systematiskt inventera olika typer av miljöer, inte enbart ängs- och betesmarker eller känt artrika platser. I den här studien jämför vi artrikedom, individantal och artsammansättning av dagfjärilar (Rophalocera) och bastardsvärmare (Zyganidaea) i naturbetesmarker och tre typer av öppna biotoper i skogslandskapet; hyggen, kraftledningsgator och skogsbilvägar. Vi delar också in fjärilarna efter val av värdväxt och flygtid på säsongen för att se om det finns några skillnader mellan biotoperna vad gäller art- och individrikedom inom dessa grupper. Vi undersöker hur mängden skog och betesmark inom det omgivande landskapet påverkar dagfjärilsfaunan på de olika platserna och hur många inventeringstillfällen (3, 5 eller 7) som krävs för att få tillförlitliga data på artrikedomen på en plats. Våra resultat visar att artsammansättningen av fjärilar skiljer sig mellan biotoperna och att alla bidrar med unika arter och således kompletterar varandra. Kraftledningsgatorhade både fler fjärilsarter och individer än de övriga biotoperna och hyggen och skogsbilvägar var lika art- och individrika som betesmarkerna. Det är därför viktigt att övervaka flera typer av miljöer och även skogsbiotoper inom framtida dagfjärilsövervakning. Eftersom alla tre skogsbiotoperna hyser en stor mångfald av fjärilar kan det vara värt att anpassa skötseln av dessa miljöer för att gynna fjärilar. I kraftledningsgator och skogsbilvägar som är relativt beständiga miljöer och som redan idag sköts med ett visst intervall är detta fullt möjligt. Betydelsen av antal inventeringstillfällen beror på vilken frågeställning man har. Vill man jämföra artrikedomen i olika miljöer eller studera förändring i artrikedom mellan år kan det kanske räcka med tre besök, men vill man ha en mer heltäckande bild av artrikedomen på en plats kan det sju eller fler besök spridda över säsongen
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| 7. |
- Berg, Åke, et al.
(författare)
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Butterflies in semi-natural pastures and power-line corridors - effects of flower richness, management, and structural vegetation characteristics
- 2013
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 6, s. 639-657
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare the butterfly assemblages in semi-natural pastures and power-line corridors and to analyse the effects of vegetation height, occurrence of trees and shrubs and different flowering vascular plant groups on butterfly diversity and abundance. Twelve of 26 analysed butterfly species were more abundant in power-line corridors than in semi-natural pastures. Only one species preferred semi-natural pastures. In semi-natural pastures butterflies were most common in segments with tall vegetation, whereas butterflies in power-line corridors were most common in segments with vegetation of short or intermediate height. Short vegetation was sparser in power-line corridors (mean cover 4%) than in semi-natural pastures (33%), whereas tall vegetation was more common in power-line corridors (59%) than in semi-natural pastures (35%). The amount of flowers was the factor that affected the abundance of most species. Twenty-one of the 26 species showed positive associations with numbers of flowers of different families. Flowers of the plant families Apiaceae, Caryophyllaceae, Primulaceae, Rubiaceae, Scrophulariaceae, and Violaceae showed positive associations with the abundance of several butterfly species. Vegetation height seems to be a limiting factor in semi-natural pastures, and less intensive management (division of pastures into grazing pens, late season grazing, grazing every second year, or reduced grazing pressure) would benefit butterflies. In power-line corridors (dominated by tall vegetation) the opposite would be beneficial for butterflies, for example more frequent clearing of vegetation along the power-line trails combined with mowing of selected areas.
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| 8. |
- Berg, Åke, et al.
(författare)
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Butterfly distribution and abundance is affected by variation in the Swedish forest-farmland landscape
- 2011
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 144, s. 2819-2831
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Tidskriftsartikel (refereegranskat)abstract
- Remaining patches of semi-natural grasslands are hot spots for biodiversity in modern agricultural landscapes. In Sweden semi-natural pastures cover approximately 500,000 ha. However, power-line corridors, road verges and clear-cuts cover larger areas (in total about 2,000,000 ha), and these open, less intensively managed habitats are potentially important for species associated with taller vegetation and flower resources (e.g. pollinating insects). The aim of the present study was to evaluate the relative importance of semi-natural pastures and the other three open habitats for butterflies in 12 forest-farmland mosaic landscapes in south central Sweden. Species composition differed significantly between habitats in multivariate analyses. Power-line corridors and semi-natural pastures harbored several species that were disproportionally abundant in these habitats (13 and 8 species, respectively), and power-line corridors also harbored several species that were classified as typical in indicator species analyses. There were more butterfly species, higher abundances and a tendency for more individuals of red-listed species in power-line corridors than in the other three habitats. Effects of the surrounding landscape composition seemed to be weaker than that of the local habitat. However, species composition was significantly associated with landscape composition and species with intermediate and low mobility were more abundant in forested landscapes than in landscapes dominated by arable fields. Analyses of flying time and host plants for larvae suggest that early flying species and species associated with dwarf shrubs were more common in power-line corridors than in the other habitats. A landscape perspective, which takes several habitats into account, is needed for conservation of butterfly communities in forest-farmland landscapes. Power-line corridors and road verges offer possibilities for creating habitats that are suitable for pollinating insects through conservation-oriented management. (C) 2011 Elsevier Ltd. All rights reserved.
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| 11. |
- Jacobs, Kevin B, et al.
(författare)
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Detectable clonal mosaicism and its relationship to aging and cancer.
- 2012
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Ingår i: Nature Genetics. - New York : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 44:6, s. 651-658
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Tidskriftsartikel (refereegranskat)abstract
- In an analysis of 31,717 cancer cases and 26,136 cancer-free controls from 13 genome-wide association studies, we observed large chromosomal abnormalities in a subset of clones in DNA obtained from blood or buccal samples. We observed mosaic abnormalities, either aneuploidy or copy-neutral loss of heterozygosity, of >2 Mb in size in autosomes of 517 individuals (0.89%), with abnormal cell proportions of between 7% and 95%. In cancer-free individuals, frequency increased with age, from 0.23% under 50 years to 1.91% between 75 and 79 years (P = 4.8 × 10(-8)). Mosaic abnormalities were more frequent in individuals with solid tumors (0.97% versus 0.74% in cancer-free individuals; odds ratio (OR) = 1.25; P = 0.016), with stronger association with cases who had DNA collected before diagnosis or treatment (OR = 1.45; P = 0.0005). Detectable mosaicism was also more common in individuals for whom DNA was collected at least 1 year before diagnosis with leukemia compared to cancer-free individuals (OR = 35.4; P = 3.8 × 10(-11)). These findings underscore the time-dependent nature of somatic events in the etiology of cancer and potentially other late-onset diseases.
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| 12. |
- S. Sichani, Matin, et al.
(författare)
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Comparison of Non-elliptic Contact Models : Towards Fast and Accurate Modelling of Wheel-Rail Contact
- 2012
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Ingår i: Proceeding of 9th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems. ; , s. 120-128
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Konferensbidrag (refereegranskat)abstract
- The demand to investigate and predict the surface deterioration phenomenain the wheel-rail interface necessitates fast and accurate contact modelling.During the past twenty years, there have been attempts to determine more realisticcontact patch and stress distributions using fast non-iterative methods.The main aim of the present work is to compare some of these state-of-theart,non-elliptic contact models available in the literature. This is consideredas the first step in introducing a fast and accurate non-elliptic contact modelthat can be used on-line with vehicle dynamics analysis. Three contact models,namely STRIPES, Kik-Piotrowski and Linder methods are implementedand compared in terms of contact patch prediction, as well as contact pressureand traction distributions. The paper also discusses the gaps to be filledin terms of contact model evaluation and the results indicate the need forbetter contact pressure and patch estimation in certain contact cases.
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| 13. |
- Sh. Sichani, Matin, et al.
(författare)
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Comparison of non-elliptic contact models : Towards fast and accurate modelling of wheel-rail contact
- 2014
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 314:1-2, s. 111-117
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Tidskriftsartikel (refereegranskat)abstract
- The demand to investigate and predict the surface deterioration phenomena in the wheel-rail interface necessitates fast and accurate contact modelling. During the past 20 years, there have been attempts to determine more realistic contact patch and stress distributions using fast simplified methods. The main aim of the present work is to compare some of these state-of-the-art, non-elliptic contact models available in the literature. This is considered as the first step to develop a fast and accurate non-elliptic contact model that can be used on-line with vehicle dynamics analysis. Three contact models, namely STRIPES, Kik-Piotrowski and Linder are implemented and compared in terms of contact patch prediction, as well as contact pressure and traction distributions. The evaluation of these models using CONTACT software indicate the need for improvement of contact patch and pressure estimation in certain contact cases.
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| 14. |
- Shahzamanian Sichani, Matin, et al.
(författare)
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A novel method to model wheel-rail normal contact in vehicle dynamics simulation
- 2014
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 52:12, s. 1752-1764
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Tidskriftsartikel (refereegranskat)abstract
- An approximate analytical method is proposed for calculating the contact patch and pressure distribution in the wheel-rail interface. The deformation of the surfaces in contact is approximated using the separation between them. This makes it possible to estimate the contact patch analytically. The contact pressure distribution in the rolling direction is assumed to be elliptic with its maximum calculated by applying Hertz' solution locally. The results are identical to Hertz's for elliptic cases. In non-elliptic cases good agreement is achieved in comparison to the more accurate but computationally expensive Kalker's variational method (CONTACT code). Compared to simplified non-elliptic contact methods based on virtual penetration, the calculated contact patch and pressure distribution are markedly improved. The computational cost of the proposed method is significantly lower than the more detailed methods, making it worthwhile to be applied to rolling contact in rail vehicle dynamics simulation. Such fast and accurate estimation of contact patch and pressure paves the way for on-line modelling of damage phenomena in dynamics simulation packages.
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| 15. |
- Shahzamanian Sichani, Matin, et al.
(författare)
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Non-Elliptic Wheel-Rail Contact Modelling in Vehicle Dynamics Simulation
- 2014
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Ingår i: The international Journal of railway technology. - 2049-5358 .- 2053-602X. ; 3:3, s. 77-94
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Tidskriftsartikel (refereegranskat)abstract
- An approximate rolling contact model is introduced for fast evaluation of the contactpatch and stress distribution in the wheel-rail interface, capable of being usedon-line with dynamics simulations. The normal part of the model is based on a novelapproach in which the surface deformations are approximated, resulting in accuratepatch and pressure estimation. The tangential part is based on an adaptation of FASTSIMalgorithm to non-elliptic patches. The new model is compared to the approximatemodel of Kik and Piotrowski and the results are evaluated using Kalker’s CONTACTcode. The comparison clearly shows that the new model is more accurate than Kikand Piotrowski’s in terms of contact patch and stress distribution as well as creepforce estimation.
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| 16. |
- Shahzamanian Sichani, Matin
(författare)
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Wheel-rail contact modelling in vehicle dynamics simulation
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The wheel-rail contact is at the core of all research related to vehicle-track interaction. This tiny interface governs the dynamic performance of rail vehicles through the loads it transmits and, like any high stress concentration zone, it is subjected to serious damage phenomena. Thus, a clear understanding of the rolling contact between wheel and rail is key to realistic vehicle dynamic simulation and damage analyses.In a multi-body-system simulation package, the essentially demanding contact problem should be evaluated in about every millisecond. Hence, a rigorous treatment of the contact is highly time consuming. Simplifying assumptions are, therefore, made to accelerate the simulation process. This gives rise to a trade-off between accuracy and computational efficiency of the contact models in use.Historically, Hertz contact solution is used since it is of closed-form. However, some of its underlying assumptions may be violated quite often in wheel-rail contact. The assumption of constant relative curvature which leads to an elliptic contact patch is of this kind. Fast non-elliptic contact models are proposed by others to lift this assumption while avoiding the tedious numerical procedures. These models are accompanied by a simplified approach to treat tangential tractions arising from creepages and spin.In this thesis, in addition to a literature survey presented, three of these fast non-elliptic contact models are evaluated and compared to each other in terms of contact patch, pressure and traction distributions as well as the creep forces. Based on the conclusions drawn from this evaluation, a new method is proposed which results in more accurate contact patch and pressure distribution estimation while maintaining the same computational efficiency. The experience gained through this Licentiate work illuminates future research directions among which, improving tangential contact results and treating conformal contacts are given higher priority.
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| 17. |
- Sichani, Martin Sh., et al.
(författare)
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A fast non-elliptic contact model for application to rail vehicle dynamics simulation
- 2014
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Konferensbidrag (refereegranskat)abstract
- An approximate rolling contact model is introduced for fast evaluation of the contact patch and stress distribution in the wheel-rail interface, capable of being used on-line with dynamics simulations. The normal part of the model is based on a novel approach in which the surface deformations are approximated, resulting in accurate patch and pressure estimation. The tangential part is based on an adaptation of the FASTSIM algorithm to non-elliptic patches. The new model is compared to the approximate model of Kik and Piotrowski and the results are evaluated using the rigorous solution of Kalker's CONTACT code. The comparison clearly shows the new model to be more accurate than Kik-Piotrowski's in terms of contact patch and stress distribution as well as creep force estimation.
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| 18. |
- Sträng, Roger, 1952-
(författare)
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En flerstämmig kulturanalys : Om värden, värderingar och motiv i skolors vardagsarbete
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to design and develop a polyphonic reanalysis instrument for analysis of school cultures, as a part of the efforts to understand and develop schools as organizations. The purpose of the new instrument is to achieve an extended possibility to highlight the values and motives underlying a school´s everyday work from the actors´ micro-oriented perspective. The concept of school culture refers to Gunnar Berg and his school development strategy of scope for action, which in turn can be understood as an empirically grounded development of Gerhard Arfwedson´s concept of school codex. The new instrument is intended to complement these two existing and long-established analytical instruments. School development is an ambiguous concept, open to different explanation and interpretation, depending on the choice of perspectives and approaches. Christopher Hodgkinson emphasizes the difficulty in conceptualizing a discussion of the motives and values held by members of an organization. It is all about subjective concepts, the meanings of which vary, depending on the situation and the context in which they are observed. A central issue in organizations is how to reconcile the organization’s nomothetic and idiographic aspirations and structures. In school organizations the problem can be understood as the dialectical interaction between institutional and organizational values. In order to provide the kind of empirical knowledge of school development that is called for, an analytical tool is required that can capture both individual and organizational and institutional aspects of the school's everyday work. My empirical evidence is drawn from cultural analysis of schools in three municipalities and municipal districts. In the reanalysis, the emerging common features were lack of continuity in school leadership and the expectations of school leaders as educational leaders to participate more actively in the everyday work. The frequent changes of directors, was by many perceived as an inhibiting and counterproductive obstacle to sustainable school improvement. The results also showed significant differences in the schools' organizational structures of formal and informal decision-making. Knowledge of the underlying patterns that affect the school's everyday work can probably be used to make the organization more transparent and malleable. The dialectical interplay between the organization and its nomothetic-idiographic aspirations differs from school to school. The driving forces in the members’ collective action clarify the relationship between the organization and its members' goals. In-depth knowledge of actors' behavior and attitudes in the context of this interaction increases the possibility of real school development on pedagogical terms to the pupils' benefit. In conclusion: The polyphonic culture assay is still an underdeveloped area. Access to the polyphonic school culture will hopefully be the starting-point for the challenge to increase new and exciting empirical knowledge of the daily work at school.
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