| 1. |
- Elks, Cathy E, et al.
(författare)
-
Thirty new loci for age at menarche identified by a meta-analysis of genome-wide association studies
- 2010
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:12, s. 1077-85
-
Tidskriftsartikel (refereegranskat)abstract
- To identify loci for age at menarche, we performed a meta-analysis of 32 genome-wide association studies in 87,802 women of European descent, with replication in up to 14,731 women. In addition to the known loci at LIN28B (P = 5.4 × 10⁻⁶⁰) and 9q31.2 (P = 2.2 × 10⁻³³), we identified 30 new menarche loci (all P < 5 × 10⁻⁸) and found suggestive evidence for a further 10 loci (P < 1.9 × 10⁻⁶). The new loci included four previously associated with body mass index (in or near FTO, SEC16B, TRA2B and TMEM18), three in or near other genes implicated in energy homeostasis (BSX, CRTC1 and MCHR2) and three in or near genes implicated in hormonal regulation (INHBA, PCSK2 and RXRG). Ingenuity and gene-set enrichment pathway analyses identified coenzyme A and fatty acid biosynthesis as biological processes related to menarche timing.
|
|
| 2. |
- Frazier-Wood, Alexis C., et al.
(författare)
-
Genetic variants associated with subjective well-being, depressive symptoms, and neuroticism identified through genome-wide analyses
- 2016
-
Ingår i: Nature Genetics. - : Nature Research (part of Springer Nature). - 1061-4036 .- 1546-1718. ; 48, s. 624-
-
Tidskriftsartikel (refereegranskat)abstract
- Very few genetic variants have been associated with depression and neuroticism, likely because of limitations on sample size in previous studies. Subjective well-being, a phenotype that is genetically correlated with both of these traits, has not yet been studied with genome-wide data. We conducted genome-wide association studies of three phenotypes: subjective well-being (n = 298,420), depressive symptoms (n = 161,460), and neuroticism (n = 170,911). We identify 3 variants associated with subjective well-being, 2 variants associated with depressive symptoms, and 11 variants associated with neuroticism, including 2 inversion polymorphisms. The two loci associated with depressive symptoms replicate in an independent depression sample. Joint analyses that exploit the high genetic correlations between the phenotypes (vertical bar(p) over cap vertical bar approximate to 0.8) strengthen the overall credibility of the findings and allow us to identify additional variants. Across our phenotypes, loci regulating expression in central nervous system and adrenal or pancreas tissues are strongly enriched for association.
|
|
| 3. |
- Gretarsdottir, Solveig, et al.
(författare)
-
Genome-wide association study identifies a sequence variant within the DAB2IP gene conferring susceptibility to abdominal aortic aneurysm
- 2010
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 42:8, s. 71-692
-
Tidskriftsartikel (refereegranskat)abstract
- We performed a genome-wide association study on 1,292 individuals with abdominal aortic aneurysms (AAAs) and 30,503 controls from Iceland and The Netherlands, with a follow-up of top markers in up to 3,267 individuals with AAAs and 7,451 controls. The A allele of rs7025486 on 9q33 was found to associate with AAA, with an odds ratio (OR) of 1.21 and P = 4.6 x 10(-10). In tests for association with other vascular diseases, we found that rs7025486[A] is associated with early onset myocardial infarction (OR = 1.18, P = 3.1 x 10(-5)), peripheral arterial disease (OR = 1.14, P = 3.9 x 10(-5)) and pulmonary embolism (OR = 1.20, P = 0.00030), but not with intracranial aneurysm or ischemic stroke. No association was observed between rs7025486[A] and common risk factors for arterial and venous diseases-that is, smoking, lipid levels, obesity, type 2 diabetes and hypertension. Rs7025486 is located within DAB2IP, which encodes an inhibitor of cell growth and survival.
|
|
| 4. |
- Ruderfer, Douglas M., et al.
(författare)
-
Mosaic copy number variation in schizophrenia
- 2013
-
Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 21:9, s. 1007-1011
-
Tidskriftsartikel (refereegranskat)abstract
- Recent reports suggest that somatic structural changes occur in the human genome, but how these genomic alterations might contribute to disease is unknown. Using samples collected as part of the International Schizophrenia Consortium (schizophrenia, n = 3518; control, n = 4238) recruited across multiple university research centers, we assessed single-nucleotide polymorphism genotyping arrays for evidence of chromosomal anomalies. Data from genotyping arrays on each individual were processed using Birdsuite and analyzed with PLINK. We validated potential chromosomal anomalies using custom nanostring probes and quantitative PCR. We estimate chromosomal alterations in the schizophrenia population to be 0.42%, which is not significantly different from controls (0.26%). We identified and validated a set of four extremely large (>10 Mb) chromosomal anomalies in subjects with schizophrenia, including a chromosome 8 trisomy and deletion of the q arm of chromosome 7. These data demonstrate that chromosomal anomalies are present at low frequency in blood cells of both control and schizophrenia subjects.
|
|
| 5. |
- Smith, Jennifer A, et al.
(författare)
-
Genome-wide association study identifies 74 loci associated with educational attainment
- 2016
-
Ingår i: Nature (London). - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 533:7604, s. 539-542
-
Tidskriftsartikel (refereegranskat)abstract
- Educational attainment is strongly influenced by social and other environmental factors, but genetic factors are estimated to account for at least 20% of the variation across individuals. Here we report the results of a genome-wide association study (GWAS) for educational attainment that extends our earlier discovery sample of 101,069 individuals to 293,723 individuals, and a replication study in an independent sample of 111,349 individuals from the UK Biobank. We identify 74 genome-wide significant loci associated with the number of years of schooling completed. Single-nucleotide polymorphisms associated with educational attainment are disproportionately found in genomic regions regulating gene expression in the fetal brain. Candidate genes are preferentially expressed in neural tissue, especially during the prenatal period, and enriched for biological pathways involved in neural development. Our findings demonstrate that, even for a behavioural phenotype that is mostly environmentally determined, a well-powered GWAS identifies replicable associated genetic variants that suggest biologically relevant pathways. Because educational attainment is measured in large numbers of individuals, it will continue to be useful as a proxy phenotype in efforts to characterize the genetic influences of related phenotypes, including cognition and neuropsychiatric diseases.
|
|
| 6. |
- Stacey, Simon N, et al.
(författare)
-
A germline variant in the TP53 polyadenylation signal confers cancer susceptibility.
- 2011
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 43:11, s. 1098-103
-
Tidskriftsartikel (refereegranskat)abstract
- To identify new risk variants for cutaneous basal cell carcinoma, we performed a genome-wide association study of 16 million SNPs identified through whole-genome sequencing of 457 Icelanders. We imputed genotypes for 41,675 Illumina SNP chip-typed Icelanders and their relatives. In the discovery phase, the strongest signal came from rs78378222[C] (odds ratio (OR) = 2.36, P = 5.2 × 10(-17)), which has a frequency of 0.0192 in the Icelandic population. We then confirmed this association in non-Icelandic samples (OR = 1.75, P = 0.0060; overall OR = 2.16, P = 2.2 × 10(-20)). rs78378222 is in the 3' untranslated region of TP53 and changes the AATAAA polyadenylation signal to AATACA, resulting in impaired 3'-end processing of TP53 mRNA. Investigation of other tumor types identified associations of this SNP with prostate cancer (OR = 1.44, P = 2.4 × 10(-6)), glioma (OR = 2.35, P = 1.0 × 10(-5)) and colorectal adenoma (OR = 1.39, P = 1.6 × 10(-4)). However, we observed no effect for breast cancer, a common Li-Fraumeni syndrome tumor (OR = 1.06, P = 0.57, 95% confidence interval 0.88-1.27).
|
|
| 7. |
- Stolk, Lisette, et al.
(författare)
-
Meta-analyses identify 13 loci associated with age at menopause and highlight DNA repair and immune pathways
- 2012
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:3, s. 260-268
-
Tidskriftsartikel (refereegranskat)abstract
- To newly identify loci for age at natural menopause, we carried out a meta-analysis of 22 genome-wide association studies (GWAS) in 38,968 women of European descent, with replication in up to 14,435 women. In addition to four known loci, we identified 13 loci newly associated with age at natural menopause (at P < 5 × 10(-8)). Candidate genes located at these newly associated loci include genes implicated in DNA repair (EXO1, HELQ, UIMC1, FAM175A, FANCI, TLK1, POLG and PRIM1) and immune function (IL11, NLRP11 and PRRC2A (also known as BAT2)). Gene-set enrichment pathway analyses using the full GWAS data set identified exoDNase, NF-κB signaling and mitochondrial dysfunction as biological processes related to timing of menopause.
|
|
| 8. |
|
|
| 9. |
- Al-Abri, Ruqaiya, et al.
(författare)
-
Sub-Picosecond Carrier Dynamics Explored using Automated High-Throughput Studies of Doping Inhomogeneity within a Bayesian Framework
- 2023
-
Ingår i: Small. - 1613-6810. ; 19:33
-
Tidskriftsartikel (refereegranskat)abstract
- Bottom–up production of semiconductor nanomaterials is often accompanied by inhomogeneity resulting in a spread in electronic properties which may be influenced by the nanoparticle geometry, crystal quality, stoichiometry, or doping. Using photoluminescence spectroscopy of a population of more than 11 000 individual zinc-doped gallium arsenide nanowires, inhomogeneity is revealed in, and correlation between doping and nanowire diameter by use of a Bayesian statistical approach. Recombination of hot-carriers is shown to be responsible for the photoluminescence lineshape; by exploiting lifetime variation across the population, hot-carrier dynamics is revealed at the sub-picosecond timescale showing interband electronic dynamics. High-throughput spectroscopy together with a Bayesian approach are shown to provide unique insight in an inhomogeneous nanomaterial population, and can reveal electronic dynamics otherwise requiring complex pump-probe experiments in highly non-equilibrium conditions.
|
|
| 10. |
- Asplund, Fredrik, 1977-, et al.
(författare)
-
The genesis of public-private innovation ecosystems : Bias and challenges
- 2021
-
Ingår i: Technological forecasting & social change. - : Elsevier. - 0040-1625 .- 1873-5509. ; 162
-
Tidskriftsartikel (refereegranskat)abstract
- The emergence of technology increasingly depends on innovation ecosystems and frequently involves actors from both industry and academia. However, value creation may experience challenges due to bias formed during public-private innovation ecosystem genesis.This empirical study of bias in a new pan-European public-private initiative provides results regarding innovation ecosystems and the individuals typically active during their genesis: value creation is biased towards the selection of incumbent firms and complement challenges, and participation is biased towards engineers with knowledge of exploitation from multiple domains and researchers with knowledge of exploitation from single domains.This suggests that the implications of the loose coupling emphasised by the innovation ecosystems discourse and the knowledge of the different contexts in which firms capture value are more complex than previously acknowledged. The practical implications are that the ability of public innovation ecosystem leadership to act early on novel technology might be offset by the inability of involved firms to commit to bringing the technology to market and that individuals typically active during public-private innovation ecosystems genesis are not ideal for handling this challenge. In fact, increasingly connected public leadership could smother the innovation ecosystem unless well-connected and multidisciplinary researchers are brought in as brokers.
|
|
| 11. |
- Audouin, L., et al.
(författare)
-
Quantifying differences between computational results and measurements in the case of a large-scale well-confined fire scenario
- 2011
-
Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 1872-759X .- 0029-5493. ; 241:1, s. 18-31
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this work was to quantify comparisons between several computational results and measurements performed during a pool fire scenario in a well-confined compartment. This collaborative work was initiated under the framework of the OECD fire research program and involves the most frequently used fire models in the fire community, including field and zone models. The experimental scenario was conducted at the French Institut de Radioprotection et de Surete Nucleaire (IRSN) and deals with a full-scale liquid pool fire in a confined and mechanically ventilated compartment representative for nuclear plants. The practical use of different metric operators and their ability to report the capabilities of fire models are presented. The quantitative comparisons between measurements and numerical results obtained from "open" calculations concern six important quantities from a safety viewpoint: gas temperature, oxygen concentration, wall temperature, total heat flux, compartment pressure and ventilation flow rate during the whole fire duration. The results indicate that it is important to use more than one metric for the validation process in order to get information on the uncertainties associated with different aspects of fire safety. (C) 2010 Elsevier B.V. All rights reserved.
|
|
| 12. |
- Becker, Joel, et al.
(författare)
-
Resource profile and user guide of the Polygenic Index Repository
- 2021
-
Ingår i: Nature Human Behaviour. - : Nature Research (part of Springer Nature). - 2397-3374. ; 51:6, s. 694-695
-
Tidskriftsartikel (refereegranskat)abstract
- Polygenic indexes (PGIs) are DNA-based predictors. Their value for research in many scientific disciplines is growing rapidly. As a resource for researchers, we used a consistent methodology to construct PGIs for 47 phenotypes in 11 datasets. To maximize the PGIs’ prediction accuracies, we constructed them using genome-wide association studies—some not previously published—from multiple data sources, including 23andMe and UK Biobank. We present a theoretical framework to help interpret analyses involving PGIs. A key insight is that a PGI can be understood as an unbiased but noisy measure of a latent variable we call the ‘additive SNP factor’. Regressions in which the true regressor is this factor but the PGI is used as its proxy therefore suffer from errors-in-variables bias. We derive an estimator that corrects for the bias, illustrate the correction, and make a Python tool for implementing it publicly available. © 2021, The Author(s), under exclusive licence to Springer Nature Limited.
|
|
| 13. |
|
|
| 14. |
- Bordogna, Marco Tito, et al.
(författare)
-
MUSCAT experiment : active free falling units for in situ measurements of temperature and density in the middle atmosphere
- 2013
-
Ingår i: European Space Agency. - ESTEC, Noordwijk, The Netherlands : ESA Communications. - 9789290922858 ; , s. 575-582
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The main scientific objective of the MUSCAT Experimentis to develop a technique to reconstruct temperatures and density profiles in the middle atmosphere using active spherical probes. The MUSCAT experiment was launched on May 9, 2013 on the REXUS-13 sounding rocket from Esrange, in northern Sweden. The experiment ejected four probes that collected raw GPS signal. The experiment design and preliminary results are presented here.
|
|
| 15. |
- Botha-le Roux, Shani, et al.
(författare)
-
Cardiovascular Profile of South African Adults with Low-Level Viremia during Antiretroviral Therapy
- 2022
-
Ingår i: Journal of Clinical Medicine. - : MDPI AG. - 2077-0383. ; 11:10
-
Tidskriftsartikel (refereegranskat)abstract
- Chronic inflammation is an HIV infection feature, contributing to elevated risk of cardiovascular disease among people with HIV, which can be induced by viral replication. A proportion of antiretroviral therapy (ART) recipients fail to achieve viral suppression, despite not meeting criteria for treatment failure, so-called low-level viremia (LLV). We investigated the relationship between LLV and an array of cardiovascular measures and biomarkers. South Africans with LLV (viral load = 50–999 copies/mL) and virological suppression (viral load <50 copies/mL) were selected from the EndoAfrica study (all receiving efavirenz-based ART) for cross-sectional comparison of vascular structure and function measures, as well as 21 plasma biomarkers related to cardiovascular risk and inflammation. Associations were investigated with univariate, multivariate, and binomial logistic regression analyses (having outcome measures above (cases) or below (controls) the 75th percentile). Among 208 participants, 95 (46%) had LLV, and 113 (54%) had viral suppression. The median age was 44 years, 73% were women, and the median ART duration was 4.5 years. Cardiovascular measures and biomarker levels were similar between these two categories. Cardiovascular function and structure measures were not associated with viremia status and having LLV did not increase the odds of having outcome measures above the 75th percentile. In this study among South African ART recipients, LLV did not associate with cardiovascular risk.
|
|
| 16. |
- Carlsson, Patrick, 1975-, et al.
(författare)
-
EPR and ab initio calculation study on the EI4 center in 4H and 6H-SiC
- 2010
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 82:23, s. 235203-
-
Tidskriftsartikel (refereegranskat)abstract
- We present new results from electron paramagnetic resonance (EPR) studies of the EI4 EPR center in 4H- and 6H-SiC. The EPR signal of the EI4 center was found to be drastically enhanced in electron-irradiated high-purity semi-insulating materials after annealing at 700-750°C. Strong EPR signals of the EI4 center with minimal interferences from other radiation-induced defects in irradiated high-purity semiinsulating materials allowed our more detailed study of the hyperfine (hf) structures. An additional large-splitting 29Si hf structure and 13C hf lines of the EI4 defect were observed. Comparing the data on the defect formation, the hf interactions and the annealing behavior obtained from EPR experiments and from ab initio supercell calculations of different carbon-vacancy related complexes, we suggest a complex between a carbon vacancy-carbon antisite and a carbon vacancy at the third neighbor site of the antisite in the neutral charge state, (VC-CSiVC)0, as a new defect model for the EI4 center.
|
|
| 17. |
- Carlsson, Patrick, 1975-, et al.
(författare)
-
Intrinsic Defects in HPSI 6H-SiC : an EPR Study
- 2009
-
Ingår i: Materials Science Forum, Vols. 600-603. - : Trans Tech Publications. ; , s. 381-384
-
Konferensbidrag (refereegranskat)abstract
- High-purity, semi-insulating 6H-SiC substrates grown by high-temperature chemical vapor deposition were studied by electron paramagnetic resonance (EPR). The carbon vacancy (VC), the carbon vacancy-antisite pair (VCCSi) and the divacancy (VCVSi) were found to be prominent defects. The (+|0) level of VC in 6H-SiC is estimated by photoexcitation EPR (photo-EPR) to be at ~ 1.47 eV above the valence band. The thermal activation energies as determined from the temperature dependence of the resistivity, Ea~0.6-0.7 eV and ~1.0-1.2 eV, were observed for two sets of samples and were suggested to be related to acceptor levels of VC, VCCSi and VCVSi. The annealing behavior of the intrinsic defects and the stability of the SI properties were studied up to 1600°C.
|
|
| 18. |
- Carlsson, Patrick, 1975-, et al.
(författare)
-
The EI4 EPR centre in 6H SiC
- 2010
-
Ingår i: Physica Scripta, Vol. T141. - : IOP Publishing. ; , s. 014013-
-
Konferensbidrag (refereegranskat)abstract
- We present the results of our recent electron paramagnetic resonance (EPR) studies of the EI4 EPR centre in electron-irradiated high-purity semi-insulating 6H SiC. Higher signal intensities and better resolution compared with previous studies have enabled a more detailed study of the hyperfine (hf) structure. Based on the observed hf structure due to the interaction with Si and C neighbours, the effective spin S = 1, the C-1h-symmetry and the annealing behaviour, we suggest a carbon vacancy-carbon antisite complex in the neutral charge state, VCVCCSi0, with the vacancies and the antisite in the basal plane, as a new defect model for the centre.
|
|
| 19. |
- Chau, Kénora, et al.
(författare)
-
Obesity and metabolic features associated with long-term developing diastolic dysfunction in an initially healthy population-based cohort
- 2018
-
Ingår i: Clinical Research in Cardiology. - : Springer Science and Business Media LLC. - 1861-0684 .- 1861-0692. ; 107:10, s. 887-896
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Diastolic dysfunction (DD) is increasingly common. However, its metabolic determinants are poorly known. This study aims to determine which metabolic and inflammatory features predict DD in initially healthy adults. Methods: We prospectively analyzed the association between metabolic features and DD in 728 initially healthy adults aged 30–60 from Eastern France enrolled in the STANISLAS population-based cohort. Clinical and biological cardiovascular features were collected at baseline (1994–1995). DD was assessed twenty years later (2011–2016) by echocardiography using current international guidelines. For replication purposes, 1463 subjects from the Malmö Preventive Project cohort were analyzed. Results: In the STANISLAS cohort, 191 subjects (26.2%) developed DD. In age-sex-adjusted logistic models, significant predictors of DD were body mass index (BMI, odds ratio for 1-standard-deviation increase (OR) 1.28, 95% CI 1.08–1.52), waist circumference (WC, OR 1.48, 95% CI 1.18–1.84), waist-hip ratio (OR 1.53, 95% CI 1.16–2.02), systolic blood pressure (OR 1.19, 95% CI 1.00–1.43) and triglycerides (TG, OR 1.18, 95% CI 1.00–1.40). Subjects with elevated WC (> 80th percentile) and TG (> 50th percentile) had a twofold higher DD risk (age-sex-adjusted odds ratio 2.00, 95% CI 1.20–3.31, P = 0.008), whereas no such interplay was observed for BMI. In the Malmö cohort, BMI was similarly associated with DD; participants with both elevated BMI and TG were at higher DD risk (age-sex-adjusted odds ratio 1.61, 95% CI 1.18–2.20, P = 0.002). Conclusions: Subjects with elevated WC and TG may have a higher long-term DD risk. Prevention targeting visceral obesity may help reduce the incidence of DD.
|
|
| 20. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
Approximate Databases : A support tool for approximate reasoning
- 2006
-
Ingår i: Journal of applied non-classical logics. - : Éditions Hermès-Lavoisier. - 1166-3081 .- 1958-5780. ; 16:1-2, s. 87-118
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes an experimental platform for approximate knowledge databases called the Approximate Knowledge Database (AKDB), based on a semantics inspired by rough sets. The implementation is based upon the use of a standard SQL database to store logical facts, augmented with several query interface layers implemented in JAVA through which extensional, intensional and local closed world nonmonotonic queries in the form of crisp or approximate logical formulas can be evaluated tractably. A graphical database design user interface is also provided which simplifies the design of databases, the entering of data and the construction of queries. The theory and semantics for AKDBs is presented in addition to application examples and details concerning the database implementation.
|
|
| 21. |
- Doherty, Patrick, et al.
(författare)
-
Towards a logical analysis of biochemical pathways
- 2004
-
Ingår i: Proceedings of the 9th European Conference on Logics in Artificial Intelligence (JELIA). - Berlin, Heidelberg : Springer. - 9783540232421 ; , s. 667-679
-
Konferensbidrag (refereegranskat)abstract
- Biochemical pathways or networks are generic representations used to model many different types of complex functional and physical interactions in biological systems. Models based on experimental results are often incomplete, e.g., reactions may be missing and only some products are observed. In such cases, one would like to reason about incomplete network representations and propose candidate hypotheses, which when represented as additional reactions, substrates, products, would complete the network and provide causal explanations for the existing observations. In this paper, we provide a logical model of biochemical pathways and show how abductive hypothesis generation may be used to provide additional information about incomplete pathways. Hypothesis generation is achieved using weakest and strongest necessary conditions which represent these incomplete biochemical pathways and explain observations about the functional and physical interactions being modeled. The techniques are demonstrated using metabolism and molecular synthesis examples.
|
|
| 22. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
Towards a Logical Analysis of Biochemical Reactions (Extended abstract)
- 2004
-
Ingår i: Proceedings of the 16th European Conference on Artificial Intelligence (ECAI). - Amsterdam : IOS Press. - 1586034529 ; , s. 997-998
-
Konferensbidrag (refereegranskat)abstract
- We provide a logical model of biochemical reactions and show how hypothesis generation using weakest sufficient and strongest necessary conditions may be used to provide additional information in the context of an incomplete model of metabolic pathways.
|
|
| 23. |
- Elmendorf, Sarah C., et al.
(författare)
-
Plot-scale evidence of tundra vegetation change and links to recent summer warming
- 2012
-
Ingår i: Nature Climate Change. - : Nature Publishing Group. - 1758-678X .- 1758-6798. ; 2:6, s. 453-457
-
Tidskriftsartikel (refereegranskat)abstract
- Temperature is increasing at unprecedented rates across most of the tundra biome. Remote-sensing data indicate that contemporary climate warming has already resulted in increased productivity over much of the Arctic, but plot-based evidence for vegetation transformation is not widespread. We analysed change in tundra vegetation surveyed between 1980 and 2010 in 158 plant communities spread across 46 locations.We found biome-wide trends of increased height of the plant canopy and maximum observed plant height for most vascular growth forms; increased abundance of litter; increased abundance of evergreen, low-growing and tall shrubs; and decreased abundance of bare ground. Intersite comparisons indicated an association between the degree of summer warming and change in vascular plant abundance, with shrubs, forbs and rushes increasing with warming. However, the association was dependent on the climate zone, the moisture regime and the presence of permafrost. Our data provide plot-scale evidence linking changes in vascular plant abundance to local summer warming in widely dispersed tundra locations across the globe.
|
|
| 24. |
- Ganna, Andrea, et al.
(författare)
-
Utilizing Twins as Controls for Non-Twin Case-Materials in Genome Wide Association Studies
- 2013
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12, s. e83101-
-
Tidskriftsartikel (refereegranskat)abstract
- Twin registries around the globe have collected DNA samples from large numbers of monozygotic and dizygotic twins. The twin sample collections are frequently used as controls in disease-specific studies together with non-twins. This approach is unbiased under the hypothesis that twins and singletons are comparable in terms of allele frequencies; i.e. there are no genetic variants associated with being a twin per se. To test this hypothesis we performed a genome-wide association study comparing the allele frequency of 572,352 single nucleotide polymorphisms (SNPs) in 1,413 monozygotic (MZ) and 5,451 dizygotic (DZ) twins with 3,720 healthy singletons. Twins and singletons have been genotyped using the same platform. SNPs showing association with being a twin at P-value < 1 × 10-5 were selected for replication analysis in 1,492 twins (463 MZ and 1,029 DZ) and 1,880 singletons from Finland. No SNPs reached genome-wide significance (P-value < 5 × 10-8) in the main analysis combining MZ and DZ twins. In a secondary analysis including only DZ twins two SNPs (rs2033541 close to ADAMTSL1 and rs4149283 close to ABCA1) were genome-wide significant after meta-analysis with the Finnish population. The estimated proportion of variance on the liability scale explained by all SNPs was 0.08 (P-value=0.003) when MZ and DZ were considered together and smaller for MZ (0.06, P-value=0.10) compared to DZ (0.09, P-value=0.003) when analyzed separately. In conclusion, twins and singletons can be used in genetic studies together with general population samples without introducing large bias. Further research is needed to explore genetic variances associated with DZ twinning.
|
|
| 25. |
|
|
| 26. |
- Gällström, Andreas, 1978-, et al.
(författare)
-
Influence of Cooling Rate after High Temperature Annealing on Deep Levels in High-Purity Semi-Insulating 4H-SiC
- 2007
-
Ingår i: Materials Science Forum, vol. 556-557. - : Trans Tech Publications. ; , s. 371-
-
Konferensbidrag (refereegranskat)abstract
- The influence of different cooling rates on deep levels in 4H-SiC after high temperature annealing has been investigated. The samples were heated from room temperature to 2300°C, followed by a 20 minutes anneal at this temperature. Different subsequent cooling sequences down to 1100°C were used. The samples have been investigated using photoluminescence (PL) and IV characteristics. The PL intensities of the silicon vacancy (VSi) and UD-2, were found to increase with a faster cooling rate.
|
|
| 27. |
- Hahn, S., et al.
(författare)
-
Contact-Less Electrical Defect Characterization of Semi-Insulating 6H-SiC Bulk Material
- 2009
-
Ingår i: Materials Science Forum Vols. 600-603. - : Trans Tech Publications. ; , s. 405-408
-
Konferensbidrag (refereegranskat)abstract
- The novel technique microwave detected photo induced current transient spectroscopy (MD-PICTS) was applied to semi-insulating 6H-SiC in order to investigate the properties of inherent defect levels. Defect spectra can be obtained in the similar way to conventional PICTS and DLTS. However, there is no need for contacting the samples, which allows for non-destructive and spatially resolved electrical characterization. This work is focused on the investigation of semi-insulating 6H-SiC grown under different C/Si-ratios. In the corresponding MD-PICTS spectra several shallow defect levels appear in the low temperature range. However the peak assignment needs further investigation. Additionally different trap reemission dynamics are obtained for higher temperatures, which are supposed to be due to different compensation effects.
|
|
| 28. |
- Halvorsen, Matthew, et al.
(författare)
-
Increased burden of ultra-rare structural variants localizing to boundaries of topologically associated domains in schizophrenia
- 2020
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 11:1, s. 1842-
-
Tidskriftsartikel (refereegranskat)abstract
- Despite considerable progress in schizophrenia genetics, most findings have been for large rare structural variants and common variants in well-imputed regions with few genes implicated from exome sequencing. Whole genome sequencing (WGS) can potentially provide a more complete enumeration of etiological genetic variation apart from the exome and regions of high linkage disequilibrium. We analyze high-coverage WGS data from 1162 Swedish schizophrenia cases and 936 ancestry-matched population controls. Our main objective is to evaluate the contribution to schizophrenia etiology from a variety of genetic variants accessible to WGS but not by previous technologies. Our results suggest that ultra-rare structural variants that affect the boundaries of topologically associated domains (TADs) increase risk for schizophrenia. Alterations in TAD boundaries may lead to dysregulation of gene expression. Future mechanistic studies will be needed to determine the precise functional effects of these variants on biology.
|
|
| 29. |
- Hellebuyck, Denis H., et al.
(författare)
-
Fire Behaviour of Less-Combustible Dielectric Liquids in a Nuclear Facility
- 2016
-
Ingår i: Fire Technology. - : Springer Science and Business Media LLC. - 0015-2684 .- 1572-8099. ; 52:2, s. 289-308
-
Tidskriftsartikel (refereegranskat)abstract
- Transformers, modulators and other high voltage electrical equipment are traditionally filled with mineral oil, which serves as a coolant and dielectric insulator. A rising trend is observed globally towards the adoption of less-combustible, bio-degradable transformer liquids at ever increasing voltages and power ratings. This paper presents a study of the fire behavior of five different dielectric transformer coolants: mineral oil, silicone liquid, synthetic ester, and two natural esters. Two types of tests were performed: comparative small-scale tests with two types of pans in the Cone Calorimeter (ISO 5660-1), and intermediate-scale pool fire experiments under the hood of an oxygen consumption calorimeter. The data obtained in this study are used in a fire engineering analysis of the evacuation and smoke removal from the 5900 m2 gallery in the planned European Spallation Source in Lund, Sweden. The comparative results indicate a wide range of fire properties for the tested liquids. The heat release rates calculated from the Cone Calorimeter experiments are reasonably consistent with tabulated values, except for the silicone liquid. The latter forms a crust on the liquid surface which significantly impedes combustion. Heat losses from the burning surface to cooler liquid below and pan boundaries have a significant effect on the burning behavior. These scale-dependent phenomena imply that great care should be taken in using small-scale burning data in a fire engineering analysis. Additional work is needed to gain a better understanding of the relation between small-scale tests and large-scale tests, and between the behavior of these liquids in pool fire experiments and that in real fires.
|
|
| 30. |
- Humphreys, Keith, et al.
(författare)
-
The Genetic Structure of the Swedish Population
- 2011
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:8, s. e22547-
-
Tidskriftsartikel (refereegranskat)abstract
- Patterns of genetic diversity have previously been shown to mirror geography on a global scale and within continents and individual countries. Using genome-wide SNP data on 5174 Swedes with extensive geographical coverage, we analyzed the genetic structure of the Swedish population. We observed strong differences between the far northern counties and the remaining counties. The population of Dalarna county, in north middle Sweden, which borders southern Norway, also appears to differ markedly from other counties, possibly due to this county having more individuals with remote Finnish or Norwegian ancestry than other counties. An analysis of genetic differentiation (based on pairwise F(st)) indicated that the population of Sweden's southernmost counties are genetically closer to the HapMap CEU samples of Northern European ancestry than to the populations of Sweden's northernmost counties. In a comparison of extended homozygous segments, we detected a clear divide between southern and northern Sweden with small differences between the southern counties and considerably more segments in northern Sweden. Both the increased degree of homozygosity in the north and the large genetic differences between the south and the north may have arisen due to a small population in the north and the vast geographical distances between towns and villages in the north, in contrast to the more densely settled southern parts of Sweden. Our findings have implications for future genome-wide association studies (GWAS) with respect to the matching of cases and controls and the need for within-county matching. We have shown that genetic differences within a single country may be substantial, even when viewed on a European scale. Thus, population stratification needs to be accounted for, even within a country like Sweden, which is often perceived to be relatively homogenous and a favourable resource for genetic mapping, otherwise inferences based on genetic data may lead to false conclusions.
|
|
| 31. |
- Janzén, Erik, 1954-, et al.
(författare)
-
The Silicon vacancy in SiC
- 2009
-
Konferensbidrag (refereegranskat)abstract
- A model is presented for the silicon vacancy in SiC. The previously reported photoluminescence spectra in 4H and 6H SiC attributed to the silicon vacancy are in this model due to internal transitions in the negative charge state of the silicon vacancy. The magnetic resonance signals observed are due to the initial and final states of these transitions.
|
|
| 32. |
- Janzén, Erik, et al.
(författare)
-
The silicon vacancy in SiC
- 2009
-
Ingår i: Physica. B, Condensed matter. - : Elsevier. - 0921-4526 .- 1873-2135. ; 404:22, s. 4354-4358
-
Tidskriftsartikel (refereegranskat)abstract
- The isolated silicon vacancy is one of the basic intrinsic defects in SiC. We present new experimental data as well as new calculations on the silicon vacancy defect levels and a new model that explains the optical transitions and the magnetic resonance signals observed as occurring in the singly negative charge state of the silicon vacancy in 4H and 6H SiC.
|
|
| 33. |
- Johannesson, Magnus, et al.
(författare)
-
Meta-GWAS Accuracy and Power (MetaGAP) Calculator Shows that Hiding Heritability Is Partially Due to Imperfect Genetic Correlations across Studies
- 2017
-
Ingår i: PLoS Genetics. - : Public Library of Science. - 1553-7404 .- 1553-7390. ; 13:1, s. 1-23
-
Tidskriftsartikel (refereegranskat)abstract
- Large-scale genome-wide association results are typically obtained from a fixed-effects meta-analysis of GWAS summary statistics from multiple studies spanning different regions and/or time periods. This approach averages the estimated effects of genetic variants across studies. In case genetic effects are heterogeneous across studies, the statistical power of a GWAS and the predictive accuracy of polygenic scores are attenuated, contributing to the so-called ‘missing heritability’. Here, we describe the online Meta-GWAS Accuracy and Power (MetaGAP) calculator (available at www.devlaming.eu) which quantifies this attenuation based on a novel multi-study framework. By means of simulation studies, we show that under a wide range of genetic architectures, the statistical power and predictive accuracy provided by this calculator are accurate. We compare the predictions from the MetaGAP calculator with actual results obtained in the GWAS literature. Specifically, we use genomic-relatedness-matrix restricted maximum likelihood to estimate the SNP heritability and cross-study genetic correlation of height, BMI, years of education, and self-rated health in three large samples. These estimates are used as input parameters for the MetaGAP calculator. Results from the calculator suggest that cross-study heterogeneity has led to attenuation of statistical power and predictive accuracy in recent large-scale GWAS efforts on these traits (e.g., for years of education, we estimate a relative loss of 51–62% in the number of genome-wide significant loci and a relative loss in polygenic score R2of 36–38%). Hence, cross-study heterogeneity contributes to the missing heritability.
|
|
| 34. |
- Kobayashi, Masatake, et al.
(författare)
-
Machine Learning-Derived Echocardiographic Phenotypes Predict Heart Failure Incidence in Asymptomatic Individuals
- 2022
-
Ingår i: JACC: Cardiovascular Imaging. - : Elsevier BV. - 1876-7591 .- 1936-878X. ; 15:2, s. 193-208
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This study sought to identify homogenous echocardiographic phenotypes in community-based cohorts and assess their association with outcomes.BACKGROUND: Asymptomatic cardiac dysfunction leads to a high risk of long-term cardiovascular morbidity and mortality; however, better echocardiographic classification of asymptomatic individuals remains a challenge.METHODS: Echocardiographic phenotypes were identified using K-means clustering in the first generation of the STANISLAS (Yearly non-invasive follow-up of Health status of Lorraine insured inhabitants) cohort (N = 827; mean age: 60 ± 5 years; men: 48%), and their associations with vascular function and circulating biomarkers were also assessed. These phenotypes were externally validated in the Malmö Preventive Project cohort (N = 1,394; mean age: 67 ± 6 years; men: 70%), and their associations with the composite of cardiovascular mortality (CVM) or heart failure hospitalization (HFH) were assessed as well.RESULTS: Three echocardiographic phenotypes were identified as "mostly normal (MN)" (n = 334), "diastolic changes (D)" (n = 323), and "diastolic changes with structural remodeling (D/S)" (n = 170). The D and D/S phenotypes had similar ages, body mass indices, cardiovascular risk factors, vascular impairments, and diastolic function changes. The D phenotype consisted mainly of women and featured increased levels of inflammatory biomarkers, whereas the D/S phenotype, consisted predominantly of men, displayed the highest values of left ventricular mass, volume, and remodeling biomarkers. The phenotypes were predicted based on a simple algorithm including e', left ventricular mass and volume (e'VM algorithm). In the Malmö cohort, subgroups derived from e'VM algorithm were significantly associated with a higher risk of CVM and HFH (adjusted HR in the D phenotype = 1.87; 95% CI: 1.04 to 3.37; adjusted HR in the D/S phenotype = 3.02; 95% CI: 1.71 to 5.34).CONCLUSIONS: Among asymptomatic, middle-aged individuals, echocardiographic data-driven classification based on the simple e'VM algorithm identified profiles with different long-term HF risk. (4th Visit at 17 Years of Cohort STANISLAS-Stanislas Ancillary Study ESCIF [STANISLASV4]; NCT01391442).
|
|
| 35. |
- Lee, James J, et al.
(författare)
-
Gene discovery and polygenic prediction from a genome-wide association study of educational attainment in 1.1 million individuals.
- 2018
-
Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 50:8, s. 1112-1121
-
Tidskriftsartikel (refereegranskat)abstract
- Here we conducted a large-scale genetic association analysis of educational attainment in a sample of approximately 1.1million individuals and identify 1,271independent genome-wide-significant SNPs. For the SNPs taken together, we found evidence of heterogeneous effects across environments. The SNPs implicate genes involved in brain-development processes and neuron-to-neuron communication. In a separate analysis of the X chromosome, we identify 10independent genome-wide-significant SNPs and estimate a SNP heritability of around 0.3% in both men and women, consistent with partial dosage compensation. A joint (multi-phenotype) analysis of educational attainment and three related cognitive phenotypes generates polygenic scores that explain 11-13% of the variance in educational attainment and 7-10% of the variance in cognitive performance. This prediction accuracy substantially increases the utility of polygenic scores as tools in research.
|
|
| 36. |
- Magnusson, Martin, et al.
(författare)
-
Abductive Reasoning with Filtered Circumscription
- 2009
-
Ingår i: Proceedings of the <em>IJCAI-09 Workshop on Nonmonotonic Reasoning, Action and Change (NRAC)</em>. - Sydney : UTSePress. - 9780980284072
-
Konferensbidrag (refereegranskat)abstract
- For logical artificial intelligence to be truly useful,its methods must scale to problems of realistic size.An interruptible algorithm enables a logical agentto act in a timely manner to the best of its knowledge,given its reasoning so far. This seems necessaryto avoid analysis paralysis, trying to thinkof every potentiality, however unlikely, beforehand.These considerations prompt us to look for alternativereasoning mechanisms for filtered circumscription,a nonmonotonic reasoning formalism usede.g. by Temporal Action Logic and Event Calculus.We generalize Ginsberg’s circumscriptive theoremprover and describe an interruptible theoremprover based on abduction that has been used tounify planning and reasoning in a logical agent architecture.
|
|
| 37. |
|
|
| 38. |
- Magnusson, Martin, 1978-
(författare)
-
Deductive Planning and Composite Actions in Temporal Action Logic
- 2007
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Temporal Action Logic is a well established logical formalism for reasoning about action and change that has long been used as a formal specification language. Its first-order characterization and explicit time representation makes it a suitable target for automated theorem proving and the application of temporal constraint solvers. We introduce a translation from a subset of Temporal Action Logic to constraint logic programs that takes advantage of these characteristics to make the logic applicable, not just as a formal specification language, but in solving practical reasoning problems. Extensions are introduced that enable the generation of action sequences, thus paving the road for interesting applications in deductive planning. The use of qualitative temporal constraints makes it possible to follow a least commitment strategy and construct partially ordered plans. Furthermore, the logical language and logic program translation is extended with the notion of composite actions that can be used to formulate and execute scripted plans with conditional actions, non-deterministic choices, and loops. The resulting planner and reasoner is integrated with a graphical user interface in our autonomous helicopter research system and applied to logistics problems. Solution plans are synthesized together with monitoring constraints that trigger the generation of recovery actions in cases of execution failures.
|
|
| 39. |
- Magnusson, Martin, 1978-, et al.
(författare)
-
Deductive Planning with Inductive Loops
- 2008
-
Ingår i: Proceedings of the 11th International Conference on Principles of Knowledge Representation and Reasoning (KR). - Menlo Park, CA, USA : AAAI Press. - 9781577353843 ; , s. 528-534
-
Konferensbidrag (refereegranskat)abstract
- Agents plan to achieve and maintain goals. Maintenance that requires continuous action excludes the representation of plans as finite sequences of actions. If there is no upper bound on the number of actions, a simple list of actions would be infinitely long. Instead, a compact representation requires some form of looping construct. We look at a specific temporally extended maintenance goal, multiple target video surveillance, and formalize it in Temporal Action Logic. The logic's representation of time as the natural numbers suggests using mathematical induction to deductively plan to satisfy temporally extended goals. Such planning makes use of a sound and useful, but incomplete, induction rule that compactly represents the solution as a recursive fixpoint formula. Two heuristic rules overcome the problem of identifying a sufficiently strong induction hypothesis and enable an automated solution to the surveillance problem that satisfies the goal indefinitely.
|
|
| 40. |
- Magnusson, Martin, 1978-, et al.
(författare)
-
Deductive Planning with Temporal Constraints
- 2007
-
Ingår i: Commonsense 2007, the 8th International Symposium on Logical Formalizations of Commonsense Reasoning,2007. - Menlo Park, CA, USA : AAAI Press. - 9781577353140
-
Konferensbidrag (refereegranskat)abstract
- Temporal Action Logic is a well established logical formalism for reasoning about action and change using an explicit time representation that makes it suitable for applications that involve complex temporal reasoning. We take advantage of constraint satisfaction technology to facilitate such reasoning through temporal constraint networks. Extensions are introduced that make generation of action sequences possible, thus paving the road for interesting applications in deductive planning. The extended formalism is encoded as a logic program that is able to realize a least commitment strategy that generates partial order plans in the context of both qualitative and quantitative temporal constraints.
|
|
| 41. |
- Magnusson, Martin, 1978-, et al.
(författare)
-
Deductive Planning with Temporal Constraints using TAL
- 2006
-
Ingår i: Proceedings of the International Symposium on Practical Cognitive Agents and Robots (PCAR). - Claremont, Australia : UWA Press. - 1740521307 ; , s. 141-
-
Konferensbidrag (refereegranskat)abstract
- Temporal Action Logic is a well established logical formalism for reasoning about action and change using an explicit time representation that makes it suitable for applications that involve complex temporal reasoning. We take advantage of constraint satisfaction technology to facilitate such reasoning through temporal constraint networks. Extensions are introduced that make generation of action sequences possible, thus paving the road for interesting applications in deductive planning. The extended formalism is encoded as a logic program that is able to realize a least commitment strategy that generates partial order plans in the context of both qualitative and quantitative temporal constraints.
|
|
| 42. |
- Magnusson, Martin, 1978-, et al.
(författare)
-
Logical Agents for Language and Action
- 2008
-
Ingår i: 4th International Artificial Intelligence and Interactive Digital Entertainment Conference AIIDE 2008,2008. - Menlo Park, CA, USA : AAAI Press. - 9781577353911
-
Konferensbidrag (refereegranskat)
|
|
| 43. |
|
|
| 44. |
|
|
| 45. |
- Magnusson, Martin, 1978-, et al.
(författare)
-
Planning Speech Acts in a Logic of Action and Change
- 2009
-
Ingår i: The Swedish AI Society Workshop 2009, SAIS 2009. - : Linköping University Electronic Press, Linköpings universitet. ; , s. 39-48
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Cooperation is a complex task that necessarily involves communication and reasoning about others’ intentions and beliefs. Multi-agent communication languages aid designers of cooperating robots through standardized speech acts, sometimes including a formal semantics. But a more direct approach would be to have the robots plan both regular and communicative actions themselves. We show how two robots with heterogeneous capabilities can autonomously decide to cooperate when faced with a task that would otherwise be impossible. Request and inform speech acts are formulated in the same first-order logic of action and change as is used for regular actions. This is made possible by treating the contents of communicative actions as quoted formulas of the same language. The robot agents then use a natural deduction theorem prover to generate cooperative plans for an example scenario by reasoning directly with the axioms of the theory.
|
|
| 46. |
- Magnusson, Martin, 1978-, et al.
(författare)
-
Temporal Action Logic for Question Answering in an Adventure Game
- 2008
-
Ingår i: Artificial General Intelligence, AGI 2008. - Amsterdam, Netherlands : IOS Press. - 9781586038335 ; , s. 236-247
-
Konferensbidrag (refereegranskat)abstract
- Inhabiting the complex and dynamic environments of modern computer games with autonomous agents capable of intelligent timely behaviour is a significant research challenge. We illustrate this using Our own attempts to build a practical agent architecture on it logicist foundation. In the ANDI-Land adventure game concept players solve puzzles by eliciting information from computer characters through natural language question answering. While numerous challenges immediately presented themselves, they took on a form of concrete and accessible problems to solve, and we present some of our initial solutions. We conclude that games, due to their demand for human-like computer characters with robust and independent operation in large simulated worlds, might serve as excellent test beds for research towards artificial general intelligence.
|
|
| 47. |
- Magnusson, Patrik K. E., et al.
(författare)
-
One CNV Discordance in NRXN1 Observed Upon Genome-wide Screening in 38 Pairs of Adult Healthy Monozygotic Twins
- 2016
-
Ingår i: Twin Research and Human Genetics. - : Cambridge University Press (CUP). - 1832-4274 .- 1839-2628. ; 19:2, s. 97-103
-
Tidskriftsartikel (refereegranskat)abstract
- Monozygotic (MZ) twins stem from the same single fertilized egg and therefore share all their inherited genetic variation. This is one of the unequivocal facts on which genetic epidemiology and twin studies are based. To what extent this also implies that MZ twins share genotypes in adult tissues is not precisely established, but a common pragmatic assumption is that MZ twins are 100% genetically identical also in adult tissues. During the past decade, this view has been challenged by several reports, with observations of differences in post-zygotic copy number variations (CNVs) between members of the same MZ pair. In this study, we performed a systematic search for differences of CNVs within 38 adult MZ pairs who had been misclassified as dizygotic (DZ) twins by questionnaire-based assessment. Initial scoring by PennCNV suggested a total of 967 CNV discor dances. The within-pair correlation in number of CNVs detected was strongly dependent on confidence score filtering and reached a plateau of r = 0.8 when restricting to CNVs detected with confidence score larger than 50. The top-ranked discordances were subsequently selected for validation by quantitative polymerase chain reaction (qPCR), from which one single similar to 120kb deletion in NRXN1 on chromosome 2 (bp 51017111-51136802) was validated. Despite involving an exon, no sign of cognitive/mental consequences was apparent in the affected twin pair, potentially reflecting limited or lack of expression of the transcripts containing this exon in nerve/brain.
|
|
| 48. |
- Magnusson, Patrick, et al.
(författare)
-
Preliminary results from the RAIN mesospheric and stratospheric aerosol particle collection experiment launched on REXUS-11
- 2013
-
Ingår i: 21st ESA Symposium. - ESTEC, Noordwijk, The Netherlands : ESA Communications. - 9789290922858 ; , s. 511-517
-
Konferensbidrag (refereegranskat)abstract
- The RAIN (Rocket deployed Atmospheric probes conducting Independent measurements in Northern Sweden) experiment demonstrates a technique for collecting aerosol particles in the middle atmosphere using multiple probes ejected from a sounding rocket. Collection samples on each probe are exposed over varying height ranges between 80 and 22 km giving an altitude distribution profile of aerosol particles. The experiment was launched on board the REXUS-11 sounding rocket on November 16, 2012 from Esrange Space Centre. The experiment operated nominally and was recovered. Initial scanning electron microscopy analysis of the collection samples indicates that aerosols were collected during the fall, however detailed analysis over all height ranges is ongoing.
|
|
| 49. |
- Manchester, The Univ., et al.
(författare)
-
High-throughput spectroscopy of semiconductor nanowires in the presence of inhomogeneity
- 2021
-
Ingår i: - : SPIE. ; , s. 20-20
-
Konferensbidrag (refereegranskat)abstract
- Controllable doping in semiconductor nanowires is essential for development of optoelectronic devices. Despite great progress, a fundamental challenge remains in controlling the uniformity of doping, particularly in the presence of relatively high levels of geometrical inhomogeneity in bottom-up growth. A relatively high doping level of 1E18 cm-3 corresponds to just ~1000 activated dopants in a 2µm long, 50nm diameter nanowire. High-throughput photoluminescence spectroscopy enables the collection of doping distributions across many (>10k) nanowires, but geometric variation adds additional uncertainty to the modelling. We present an approach that uses large datasets of doping and emission intensity to infer both doping and diameter across a growth, and apply Bayesian methods to study the underlying distributions in Zn-doped aerotaxy-grown GaAs nanowires. This new big-data enabled approach provides a route to exploit inherent inhomogeneity to reveal fundamental recombination mechanisms.
|
|
| 50. |
|
|
