1. |
- Axell, Erik, et al.
(author)
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On the Optimal K-term Approximation of a Sparse Parameter Vector MMSE Estimate
- 2009
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In: Proceedings of the 2009 IEEE Workshop on Statistical Signal Processing (SSP'09). - : IEEE. - 9781424427093 ; , s. 245-248
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Conference paper (peer-reviewed)abstract
- This paper considers approximations of marginalization sums thatarise in Bayesian inference problems. Optimal approximations ofsuch marginalization sums, using a fixed number of terms, are analyzedfor a simple model. The model under study is motivated byrecent studies of linear regression problems with sparse parametervectors, and of the problem of discriminating signal-plus-noise samplesfrom noise-only samples. It is shown that for the model understudy, if only one term is retained in the marginalization sum, thenthis term should be the one with the largest a posteriori probability.By contrast, if more than one (but not all) terms are to be retained,then these should generally not be the ones corresponding tothe components with largest a posteriori probabilities.
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2. |
- Hirai, Hiroki, et al.
(author)
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Selective screening of secretory vesicle-associated proteins for autoantigens in type 1 diabetes: VAMP2 and NPY are new minor autoantigens
- 2008
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In: Clinical Immunology. - : Elsevier BV. - 1521-6616. ; 127:3, s. 366-374
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Journal article (peer-reviewed)abstract
- The four major autoantigens (IA-2, IA-2 beta, GAD65 and insulin) of type 1 diabetes are all associated with dense core or synaptic vesicles. This raised the possibility that other secretory vesicle-associated proteins might be targets of the autoimmune response in type 1 diabetes. To test this hypothesis 56 proteins, two-thirds of which are associated with secretory vesicles, were prepared by in vitro transcription/translation and screened for autoantibodies by liquid phase radioimmunoprecipitation. Two secretory vesicle-associated proteins, VAMP2 and NPY, were identified as new minor autoantigens with 21% and 9%, respectively, of 200 type 1 diabetes sera reacting positively. These findings add support to the hypothesis that secretory vesicle-associated proteins are particularly important, but not the exclusive, targets of the autoimmune response in type 1 diabetes. Selective screening of the human proteome offers a useful approach for identifying new autoantigens in autoimmune diseases.
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3. |
- Larsson, Bengt, et al.
(author)
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Molecular oxygen in the rho Ophiuchi cloud
- 2007
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In: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 466:3, s. 5-
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Journal article (peer-reviewed)abstract
- Context: Molecular oxygen, O2, has been expected historically to be an abundant component of the chemical species in molecular clouds and, as such, an important coolant of the dense interstellar medium. However, a number of attempts from both ground and from space have failed to detect O2 emission.Aims: The work described here uses heterodyne spectroscopy from space to search for molecular oxygen in the interstellar medium. Methods: The Odin satellite carries a 1.1 m sub-millimeter dish and a dedicated 119 GHz receiver for the ground state line of O2. Starting in 2002, the star forming molecular cloud core ρ Oph A was observed with Odin for 34 days during several observing runs.Results: We detect a spectral line at v_LSR =+3.5 km s-1 with Δ v_FWHM=1.5 km s-1, parameters which are also common to other species associated with ρ Oph A. This feature is identified as the O2 (NJ = 11 - 1_0) transition at 118 750.343 MHz.Conclusions: The abundance of molecular oxygen, relative to H{2} , is 5 × 10-8 averaged over the Odin beam. This abundance is consistently lower than previously reported upper limits.Based on observations with Odin, a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the National Technology Agency of Finland (Tekes) and Centre National d'Étude Spatiale (CNES). The Swedish Space Corporation has been the industrial prime contractor and also is operating the satellite. Appendix A is only available in electronic form at http://www.aanda.org
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4. |
- Larsson, Helena, et al.
(author)
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Children developing type 1 diabetes before 6 years of age have increased linear growth independent of HLA genotypes
- 2008
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In: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 51:9, s. 1623-1630
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Journal article (peer-reviewed)abstract
- Aims/hypothesis High birthweight and increased childhood growth are risk factors for type 1 diabetes. Relative birthweight is associated with HLA genotypes that confer a high risk of diabetes. Our aims were to test whether young children prior to clinical onset of type 1 diabetes have increased: (1) birthweight or birth length standard deviation scores (SDS), (2) height development SDS, or (3) BMI SDS during first 18 months of life and whether these parameters are related to HLA genotypes or mid-parental height (MPH). Methods Birthweight, birth length, weight and height were obtained from 58 type 1 diabetes children and 155 controls matched for HLA or not in the Diabetes Prediction in Skane study. Results Birth length SDS corrected for MPH was increased in children developing diabetes compared with all (p < , 0.048) and with non-HLA- (p < , 0.050) but not with HLA-matched controls. Children developing diabetes had increased height gain at 0 to 18 months of age (p < ; 0.005). Diabetic children were significantly taller from 6 to 18 months of age when correcting for MPH compared with non-HLA-matched as well as HLA-matched controls, but BMI was not increased. Conclusions/interpretation Birth length SDS was associated with diabetes risk HLA. When corrected for MPH, children developing diabetes were taller at birth than non-HLA- but not taller than HLA-matched controls. Diabetic children had increased MPH-corrected height up to 18 months of age compared with both HLA- and non-HLA-matched controls. High-risk HLA affects prenatal growth, but other factors may explain the increased postnatal linear growth in children developing diabetes.
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5. |
- Larsson, Niklas, et al.
(author)
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Continuous flow hollow fiber liquid-phase microextraction and monitoring of NSAID pharmaceuticals in a sewage treatment plant effluent
- 2009
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In: Analytical Methods. - : Royal Society of Chemistry (RSC). - 1759-9660 .- 1759-9679. ; 1:1, s. 59-67
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Journal article (peer-reviewed)abstract
- A method for simultaneous extraction and quantification Of four non-steroidal anti-inflammatory drugs (NSAIDs) based on continuous flow hollow fiber liquid-phase microextraction (CFHF-LPME) was developed. The effect of sample flow rate, acceptor flow rate, type of acceptor flow (continuous, semi-continuous or forward-backward), type of supported liquid membrane and sample volume was studied. The extraction of the final method was linear over an environmentally relevant concentration range and yielded high enrichment factors (720-940 times) in reagent water and (270-800 times) in sewage water for all analytes within 45 min. Repeatability was best (RSD 6-15%) during the first 30 min of extraction. The optimised method was used to monitor the occurrence and fate of the four NSAIDs in a Swedish sewage treatment plant (STP) effluent, which is discharged into a system of ponds before release into a river, during the period May-September 2008. All four analytes were detected at concentrations up to 0.92 mu g L-1 ketoprofen, 0.08 mu g L-1 naproxen, 0.43 mu g L-1 diclofenac and 0.25 mu g L-1 ibuprofen. A concentration drop during the summer was observed. For diclofenac and ketoprofen significant removal in the primary recipient pond system was observed. The presence of the studied pharmaceuticals in STP effluent together with concern about their environmental effects makes monitoring of their occurrence and knowledge of their environmental fate important. The proposed method provides a basis for automation of extraction towards on-site extraction using CFHF-LPME.
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7. |
- Lindehammer, Sabina, et al.
(author)
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Temporal trends of HLA genotype frequencies of type 1 diabetes patients in Sweden from 1986 to 2005 suggest altered risk
- 2008
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In: Acta Diabetologica. - : Springer Science and Business Media LLC. - 0940-5429 .- 1432-5233. ; 45:4, s. 231-5
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Journal article (peer-reviewed)abstract
- The aim of this study was to compare the frequency of human leukocyte antigen (HLA) genotypes in 1-18-year-old patients with type 1 diabetes newly diagnosed in 1986-1987 (n = 430), 1996-2000 (n = 342) and in 2003-2005 (n = 171). We tested the hypothesis that the HLA DQ genotype distribution changes over time. Swedish type 1 diabetes patients and controls were typed for HLA using polymerase chain reaction amplification and allele specific probes for DQ A1* and B1* alleles. The most common type 1 diabetes HLA DQA1*-B1*genotype 0501-0201/0301-0302 was 36% (153/430) in 1986-1987 and 37% (127/342) in 1996-2000, but decreased to 19% (33/171) in 2003-2005 (P \ 0.0001). The 0501-0201/0501-0201 genotype increased from 1% in 1986-1987 to 7% in 1996-2000 (P = 0.0047) and to 5% in 2003-2005 (P > 0.05). This study in 1-18-year-old Swedish type 1 diabetes patients supports the notion that there is a temporal change in HLA risk.
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9. |
- Abidin, Aysajan, et al.
(author)
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Special Properties of Strongly Universal2 Hash Functions Important in Quantum Cryptography
- 2009
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In: AIP Conference Proceedings, ISSN 0094-243X, Foundations of Probability and Physics—5, Växjö, augusti 2008. - New York : American Institute of Physics. ; , s. 289-293
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Conference paper (peer-reviewed)abstract
- Secure message authentication is an important part of Quantum Key Distribution. In this paper we analyze special properties of a Strongly Universal2 hash function family, an understanding of which is important in the security analysis of the authentication used in Quantum Cryptography. We answer the following question: How much of Alices message does Eve need to influence so that the message along with its tag will give her enough information to create the correct tag for her message?
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10. |
- Abidin, Aysajan, et al.
(author)
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Vulnerability of "A Novel Protocol-Authentication Algorithm Ruling out a Man-in-the-Middle Attack in Quantum Cryptography"
- 2009
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In: International Journal of Quantum Information. - 0219-7499. ; 7:5, s. 1047-1052
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Journal article (peer-reviewed)abstract
- In this paper, we review and comment on "A novel protocol-authentication algorithm ruling out a man-in-the-middle attack in quantum cryptography" [M. Peev et al., Int. J. Quant. Inf. 3 (2005) 225]. In particular, we point out that the proposed primitive is not secure when used in a generic protocol, and needs additional authenticating properties of the surrounding quantum-cryptographic protocol.
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