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- Vlemmings, Wouter, 1974
(author)
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Magnetic fields around AGB stars and Planetary Nebulae
- 2014
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In: Proceedings of the International Astronomical Union. - 1743-9213 .- 1743-9221. ; 9:S302, s. 389-397
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Journal article (peer-reviewed)abstract
- Stars with a mass up to a few solar masses are one of the main contributors to the enrichment of the interstellar medium in dust and heavy elements. However, while significant progress has been made, the process of the mass-loss responsible for this enrichment is still not exactly known and forces beyond radiation pressure might be required. Often, the mass lost in the last phases of the stars life will become a spectacular planetary nebula. The shaping process of often strongly a-spherical PNe is equally elusive. Both binaries and magnetic fields have been suggested to be possible agents although a combination of both might also be a natural explanation. Here I review the current evidence for magnetic fields around AGB and post-AGB stars pre-Planetary Nebulae and PNe themselves. Magnetic fields appear to be ubiquitous in the envelopes of apparently single stars, challenging current ideas on its origin, although we have found that binary companions could easily be hidden from view. There are also strong indications of magnetically collimated outflows from post-AGB/pre-PNe objects supporting a significant role in shaping the circumstellar envelope. © International Astronomical Union 2014.
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| 4. |
- Hebelka, Hanna, 1977, et al.
(author)
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Loading of the Spine in Low Back Pain Patients Does Not Induce MRI Changes in Modic Lesions: A Prospective Clinical Study
- 2022
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In: Diagnostics (Basel). - : MDPI AG. - 2075-4418. ; 12:8
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Journal article (peer-reviewed)abstract
- Modic changes (MCs) are gaining increased interest as potential generators of low back pain (LBP). The current aim was to investigate possible spinal loading effects on the MRI signal in MCs in patients with LBP. Supine lumbar MRIs were performed and immediately repeated with axial loading in 100 LBP patients. A total of 43 patients (23 male, mean age 45.7 years) had MCs. Each Modic was outlined on all sagittal T2-weighted images (>25% affected vertebrae). For reference, regions of interest were placed in both vertebrae without Modic and in Modic-free tissue in vertebrae with Modic. The Modic signal intensity, normalized to cerebrospinal fluid, and Modic volume were compared between MRIs with and without spinal loading. Of the 94 MCs, 36.2% (n = 34) were type I, 58.5% (n = 55) were type II, and 5.3% (n = 5) were type III. No differences in Modic volume (mean 0.046 cm3; p = 0.25) between the MRIs with and without spinal loading were found. In addition, no significant changes in Modic signal were induced by loading (mean 1.5% difference; p = 0.308). Loading increased the signal in the reference regions of interest in vertebrae both with Modic (mean 5.5%; p = 0.002) and without (mean 3.5%; SD 0.09; p = 0.02). To conclude, MRIs performed with and without spinal loading showed no change in either volume or signal of MCs, suggesting that most MCs are not instantaneously influenced by biomechanical load.
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| 5. |
- Naumann, Clemens, et al.
(author)
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Ethene/nitrous oxide mixtures as green propellant to substitute hydrazine : Reaction mechanism validation
- 2020
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In: International Journal of Energetic Materials and Chemical Propulsion. - 2150-766X. ; 19:1, s. 65-71
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Journal article (peer-reviewed)abstract
- Reaction mechanism validation for nitrogen-diluted ethane/nitrous oxide mixtures at stoichiometric conditions has been performed using ignition delay time measurements at p = 1, 4, and 16 bar as well as laminar flame speed measurements at p = 1 and 3 bar. The predictive capability of the public domain mechanism GRI 3.0 was improved considerably by adapting some reactions within the nitrogen subsystem and optimizing the most sensitive reactions with respect to selected optimization targets (i.e., ignition delay time and selected laminar flame speed measurements) within the published error bounds.
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| 7. |
- Zhu, Huiming, et al.
(author)
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Bayesian multivariate monitoring models for process mean vectors based on multistage predictive distributions
- 2011
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In: Hunan Daxue Xuebao (Ziran Kexue Ban). - 1674-2974. ; 38:3, s. 82-86
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Journal article (peer-reviewed)abstract
- The aim of this paper is to utilize sample information in different stages and solve the parameter uncertainty risk in statistical process control. This paper introduces a reference prior distribution for the parameters in quality models, and constructs the warning lines and action lines to monitor the mean vectors change according to the predictive distribution as well as the relationship between the multivariate t distribution and F distribution. When the current stage is under control, the parametric posterior distribution is considered to be their priori distribution in the next stage, in which the sequential Bayesian mean vector control method is established.
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| 8. |
- Baskaran, Karthikeyan, et al.
(author)
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Stability of fixation in diabetes patients with and without clinically significant macular edema
- 2014
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Conference paper (peer-reviewed)abstract
- Purpose - Eye diseases affecting central vision impair fixation and interfere with day-to-day tasks such as reading. Diabetic retinopathy and clinically significant macular edema (CSME) are leading causes of visual impairment in diabetes patients. The aim of this study is to find whether diabetic patients with CSME have poorer fixation stability compared to patients without CSME, by analyzing the fundus images obtained from the Laser Scanning Digital Camera (LSDC).Methods - Two hundred underserved, diabetic patients were screened for diabetic retinopathy at the Eastmont Wellness Center within the EyePACS telemedicine network, using LSDC. One eye of each patient who had diabetic retinopathy was included in this study. Non-mydriatic color fundus photos were classified for presence of CSME by two independent, certified EyePACS graders. The first 50 patients (25 males & 25 females) with CSME were selected and 50 (27 males & 23 females) diabetic patients without CSME were selected as controls. Mean age was 59 (±9) years for patients with CSME and was 55 (±10) years for patients without CSME. The subjects included 53% Hispanics, 26% African Americans and 21% other. A series of 20 images (36 deg field, 1024 X 1024 pixels, and 850 nm) were acquired at 11 fps. Eye positions were obtained by selecting a region of interest in the first image of each series and aligning the remaining images to that region by cross-correlation. The bi-contour ellipse area (BCEA) and the standard deviation of the Euclidean distance (SDED) were used to quantify fixation stability.Results - The fixation stability for patients with CSME was significantly worse than for those without CSME (t test: p < 0.001, 0.007 for BCEA and SDED, respectively). The mean fixation stability obtained by the BCEA metric was 2.74 (±0.40) log(minArc2) and 2.34 (±0.42) log(minArc2) for patients with and without CSME, respectively. For SDED the mean was 48.4 (±28.8) microns and 34.6 (±20.4) microns for patients with and without CSME, respectively. The correlation with age was not significant for either group (R2 = 0.052, 0.011).Conclusions - Diabetic patients with CSME had poorer fixation stability than patients without CSME for both metrics. Fixation stability is a potential tool for assessing macular function and could be used for tracking the treatment and progression of macular edema.The LSDC images provide one method to quantify fixation stability rapidly.
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| 11. |
- Hendil-Forssell, Peter, 1983-, et al.
(author)
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Engineering the esterase/acyltransferase from Mycobacterium smegmatis : extended substrate scope for amide synthesis in water
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Other publication (other academic/artistic)abstract
- Some esterases/lipases display high acyl transfer activity, favoring alcoholysis over hydrolysis, which make them valuable catalysts for synthesis reactions in aqueous media. An esterase from Mycobacterium smegmatis, MsAcT, has been characterized as an efficient catalyst for ester synthesis in water. The acyl donor specificity for MsAcT was however found to be very narrow and the enzyme displayed no activity towards esters with larger acyl group than butyrate. With rational engineering, the narrow acyl donor specificity of wild type MsAcT enzyme was altered and variants displaying extended substrate scope were generated. A double mutant, T93A/F154A, could accommodate methyl nonanoate as substrate, i.e. five carbons longer acyl group as compared to wild type, without compromising the acyl transfer capabilities. With similar selectivity towards a broad range of acyl donors (propionate to nonanoate) this is a more applicable catalyst than the wild type. Furthermore, the T93A/F154A variant was an efficient catalyst for synthesis of N-benzylhexanamide in water using methyl hexanoate as acyl donor, which is not a substrate for the wild type enzyme. The conversion reached 81% and the enzyme variant could potentially be used to produce amides in water with a wide variety of acyl donors.
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| 12. |
- Hinnfors, Jonas, 1956
(author)
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Kan Juholt ena ett vilset S?
- 2011
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In: Svenska Dagbladet/Brännpunkt. ; :25 mars 2011
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Other publication (other academic/artistic)
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| 13. |
- Spasenić, Jelena, 1979-
(author)
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The Significance of Serbia’s Recent War-Ridden Past for Young People’s Identity Perceptions
- 2015
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In: Glasnik Etnografskog Instituta SANU. - 0350-0861 .- 2334-8259. ; 63:2, s. 317-336
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Journal article (peer-reviewed)abstract
- How do we ethnographically chart the ways in which a recent war-ridden past features in everyday identifications of young adults, who have little or no direct experience of that past? One way is to treat this question as a matter of how everyday knowledge is constituted and transferred between individuals, as well as how historical legacies, cultural and political models enter their life-worlds, what they think and know, and who they are. These inquiries stood at the core of the study I con- ducted among two high-school classes between 2007 and 2009 in Novi Sad. This article will shed light on my main conclu- sions and problematize the notion of collective confrontation with the past. My contention is that arguments for collective confrontation with the past, together with official policies in- formed by this discourse, need to take into account social psy- chological mechanisms of identity construction in order to avoid the assumption that knowledge and moral insight can be mapped onto people’s minds.
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