| 1. |
- Aourir, Nouria, et al.
(författare)
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Theoretical hyperfine structures of F-19 I and O-17 I
- 2018
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : American Physical Society. - 2469-9926 .- 2469-9934. ; 97:3
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Tidskriftsartikel (refereegranskat)abstract
- Multiconfiguration Hartree-Fock (MCHF) and multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations are performed for the 2p(5) P-2 degrees, 2p(4)(P-3)3s P-4, 2p(4)(P-3)3s P-2, and 2p(4)(P-3)3 p S-4 degrees states of F-19 I to determine their hyperfine constants. Several computing strategies are considered to investigate electron correlation and relativistic effects. High-order correlation contributions are included in MCHF calculations based on single and double multireference expansions. The largest components of the single reference MCHF wave functions are selected to define the multireference (MR) sets. In this scheme, relativistic corrections are evaluated in the Breit-Pauli approximation. A similar strategy is used for the calculation of MCDHF relativistic wave functions and hyperfine parameters. While correlation and relativistic corrections are found to be rather small for the ground state, we highlight large relativistic effects on the hyperfine constant A(3/2) of 2p(4)(P-3)3 p(4)S(degrees) and, to a lesser extent, on A(1/2) of 2p(4)(P-3)3s P-4. As expected for such a light system, electron correlation effects dominate over relativity in the calculation of the hyperfine interaction of all other levels considered. We also revisit the hyperfine constants of 2p(3)((4)(S))3s S-5 degrees and 2p(3)(S-4)3 p P-5 in O-17 using similar strategies. The results are found to be in excellent agreement with experiment.
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| 2. |
- Dimmler, Martin, et al.
(författare)
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On-line arithmetic for real-time control of microsystems
- 1999
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Ingår i: IEEE/ASME transactions on mechatronics. - Piscataway, NJ : IEEE Press. - 1083-4435 .- 1941-014X. ; 4:2, s. 213-217
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Tidskriftsartikel (refereegranskat)abstract
- The integration of microcontrollers within mechanical systems is a current trend. However, decreasing the size of the system and satisfying higher precision requirements make it necessary to reevaluate the common signal processing techniques for controller implementations, because limited controller size, computation speed, and power consumption become major topics. In this paper, we demonstrate that serial computations with the most significant digits first, that is, on-line arithmetic, offer an important potential for real-time control. They enable a combination of traditional functions, such as analog-to-digital converters and control data computations. This leads to very efficient controller implementations with small size, high speed, and low power consumption. After a brief description of the requirements and challenges of microsystem controller design, the use of on-line arithmetic for real-time control is proposed. A short introduction to on-line arithmetic is given and control-specific implementation guidelines are presented and finally applied to a simple test system.
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| 3. |
- Dimofte, T., et al.
(författare)
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Exact results for perturbative Chern-Simons theory with complex gauge group
- 2009
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Ingår i: Communications in Number Theory and Physics. - : International Press of Boston. - 1931-4523 .- 1931-4531. ; 3:2, s. 363-443
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Tidskriftsartikel (refereegranskat)abstract
- We develop several methods that allow us to compute all-loop partition functions in perturbative Chern-Simons theory with complex gauge group GC, sometimes in multiple ways. In the background of a non-abelian irreducible flat connection, perturbative GC invariants turn out to be interesting topological invariants, which are very different from the finite-type (Vassiliev) invariants usually studied in a theory with compact gauge group G and a trivial flat connection. We explore various aspects of these invariants and present an example where we compute them explicitly to high loop order. We also introduce a notion of "arithmetic topological quantum field theory" and conjecture (with supporting numerical evidence) that SL(2, C) Chern-Simons theory is an example of such a theory.
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| 4. |
- Talreja, Ramesh
(författare)
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On the role of damage mechanics in life prediction of composite structures
- 1998
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Ingår i: American Society of Mechanical Engineers. Aerospace Division. Publication AD. - 0733-4230. ; 56, s. 149-
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Tidskriftsartikel (refereegranskat)abstract
- Life prediction of composite structures is still heavy in empiricism. In order to reduce the burden of extensive data generation and proof testing, and to thereby reduce cost, resort must be made to predictive, physically based models. A field with this as a central objective, and with the capability to merge elements of materials science and mechanics, is damage mechanics. This paper will address how specifically damage mechanics may be able to render life prediction methodologies a scientific basis. First, we shall discuss the essential, sequential and interactive elements of a life prediction methodology relevant to composite structures, identifying the role of damage mechanics in such a scheme. We shall then outline a philosophy (conceptual structure) of an approach to life prediction. A simple scenario will then be treated to illustrate the ideas involved. Finally, the multiple ways by which damage mechanics can be implemented will be discussed. The limitations inherent in isolationist (pure) forms of damage mechanics will be discussed, laying bare the need for synergistic approaches. One such approach, and the progress made in achieving it, will then be described. The references cited below report related work by this author and his associates.
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| 5. |
- Amelina, Hanna, 1983-
(författare)
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Proteomics in biomarker research : Insights into the effects of aging and environment on biological systems
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Proteomics is the global analysis of proteins that covers a broad range of technologies aimed at determining the identity and quantity of proteins expressed in the cell, their three-dimensional structure and interaction partners. In contrast to genome, proteome reflects more accurately on the dynamic state of the cell, tissue, or an organism. Therefore much is expected from proteomics to yield better disease markers for early diagnosis and therapy monitoring, as well as biomarkers that would indicate environmental exposure or provide prediction of biological age. In this thesis, I have developed and applied robust and sensitive subproteomic approaches to study the effect of aging as well as and environmental pollution using different animal models. In the first part, a high-throughput proteomic method based on liquid chromatography coupled to 2-dimensional gel electrophoresis (LC/2-DE) was developed. The usefulness of this method has been demonstrated by applying it to the assessment of marine pollution in a field experiment. Next, I have utilized this subproteomic approach to study the effect of aging in mouse kidney of both genders. As a result, a protein expression signature of aging kidney was obtained, revealing gender-dependent alterations in proteome profiles of aging mouse kidney. In order to further reduce the dynamic range of protein expression and increase the sensitivity of proteomic analysis, I have applied a shotgun mass spectrometry-based proteomic approach using isobaric tags for relative and absolute quantification (iTRAQ) coupled to liquid chromatography and tandem mass spectrometry (LC-MS/MS) to study age-related differences in peroxisome-enriched fractions from mouse liver. Only eight proteins showed statistically significant difference in expression (p<0.05) with moderate folds. This study indicates that age-depended changes in the liver proteome are minimal, suggesting that its proteome is efficiently maintained until certain age. Finally, in the context of aging studies and the role of peroxisomes in aging, I have tested the utility of cell-penetrating peptides (CPPs) as agents for protein delivery into acatalasemic peroxisomes using yeast as a model. The results obtained suggest that CPPs may be suitable for the delivery of antioxidants to peroxisomes and in future could provide a tool for the protein therapy of age-related diseases.
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| 6. |
- Baburin, Aleksei, et al.
(författare)
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Age, Period and Cohort Effects On Alcohol Consumption In Estonia, 1996-2018
- 2021
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Ingår i: Alcohol and Alcoholism. - : Oxford University Press. - 0735-0414 .- 1464-3502. ; 56:4, s. 451-459
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To analyse the independent effects of age, period and cohort on estimated daily alcohol consumption in Estonia.METHODS: This study used data from nationally representative repeated cross-sectional surveys from 1996 to 2018 and included 11,717 men and 16,513 women aged 16-64 years in total. The dependent variables were consumption of total alcohol and consumption by types of beverages (beer, wine and strong liquor) presented as average daily consumption in grams of absolute alcohol. Mixed-effects negative binomial models stratified by sex were used for age-period-cohort analysis.RESULTS: Alcohol consumption was highest at ages 20-29 years for both men and women and declined in older ages. Significant period effects were found indicating that total alcohol consumption and consumption of different types of beverages had increased significantly since the 1990s for both men and women. Cohort trends differed for men and women. Men born in the 1990-2000s had significantly lower daily consumption compared to earlier cohorts, whereas the opposite was found for women.CONCLUSION: While age-related patterns of alcohol consumption are aligned with life course stages, alcohol use has increased over the study period. Although the total daily consumption among men is nearly four times higher than among women, the cohort trends suggest convergence of alcohol consumption patterns for men and women.
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