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| 2. |
- Larson, Magnus, et al.
(författare)
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Analysis and modeling of field data on coastal morphological evolution over yearly and decadal time scales. Part 1: Background and linear techniques
- 2003
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Ingår i: Journal of Coastal Research. - 0749-0208. ; 19:4, s. 760-775
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Tidskriftsartikel (refereegranskat)abstract
- A number of statistical techniques to analyze and model coastal morphological evolution over yearly and decadal (i.e., long-term) time scales based on field data are presented. After a general introduction to long-term morphological modeling, mainly linear methods are discussed, whereas nonlinear methods are treated in a companion paper (SOUTHGATE et al., 2001). The theoretical background to the methods introduced is summarized and examples of field applications are given to illustrate each method. High-quality field data sets from different sites in the world, including Germany, The Netherlands, and United States, were employed in these examples. The analysis and modeling techniques used encompassed bulk statistics (mean, standard deviation, correlation etc), random sine functions, empirical orthogonal functions, canonical correlation analysis, and principal oscillation pattern analysis. Besides an evaluation of how suitable respective technique is for analyzing and modeling long-term morphological evolution, some general observations are presented regarding scales of morphological response as derived from the field applications. Data describing the evolution of both natural and anthropogenically affected coastal systems were studied. All methods investigated proved their usefulness for extracting characteristics of long-term morphological evolution, as well as for modeling this evolution, when applied under the right circumstances. However, more sophisticated techniques rely on more data in time and space, which is typically the limiting factor in the application of statistical methods as those presented here.
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| 3. |
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| 4. |
- Nilsson, M., et al.
(författare)
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Evolution of Human Calicivirus RNA in Vivo : Accumulation of Mutations in the Protruding P2 Domain of the Capsid Leads to Structural Changes and Possibly a New Phenotype
- 2003
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Ingår i: Journal of Virology. - 0022-538X .- 1098-5514. ; 77:24, s. 13117-13124
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Tidskriftsartikel (refereegranskat)abstract
- In the present study we report on evolution of calicivirus RNA from a patient with chronic diarrhea (i.e., lasting >2 years) and viral shedding. Partial sequencing of open reading frame 1 (ORF1) from 12 consecutive isolates revealed shedding of a genogroup II virus with relatively few nucleotide changes during a 1-year period. The entire capsid gene (ORF2) was also sequenced from the same isolates and found to contain 1,647 nucleotides encoding a protein of 548 amino acids with similarities to the Arg320 and Mx strains. Comparative sequence analysis of ORF2 revealed 32 amino acid changes during the year. It was notable that the vast majority of the cumulative amino acid changes (8 of 11) appeared within residues 279 to 405 located within the hypervariable domain (P2) of the capsid protein and hence were subject to immune pressure. An interesting and novel observation was that the accumulated amino acid changes in the P2 domain resulted in predicted structural changes, including disappearance of a helix structure, and thus a possible emergence of a new phenotype. FUT2 gene polymorphism characterization revealed that the patient is heterozygous at nucleotide 428 and thus Secretor+, a finding in accordance with the hypothesis of FUT2 gene polymorphism and calicivirus susceptibility. To our knowledge, this is the first report of RNA evolution of calicivirus in a single individual, and our data suggest an immunity-driven mechanism for viral evolution. We also report on chronic virus excretion, immunoglobulin treatment, and modification of clinical symptoms, our observations from these studies, together with the FUT2 gene characterization, may lead to a better understanding of calicivirus pathogenesis.
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| 5. |
- Hansbo, Peter, et al.
(författare)
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A simple nonconforming bilinear element for the elasticity problem
- 2001
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Ingår i: Trends in computational structural mechanics. - BARCELONA : INT CENTER NUMERICAL METHODS ENGINEERING. - 9788489925779 ; , s. 317-327
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We look at the mixed non-conforming Rannacher-Turek (RT) element from the point of view of discontinuous Galerkin methods. In the case of the elasticity operator, for which the RT element is not stable in that it does not (in general) fulfill a discrete horn's inequality, the discontinuous framework naturally suggests the appearance of (weakly consistent) stabilization terms. We thus obtain a modifed, stable and locking free, version of the RT element for the elasticity problem. We also give some implementation aspects of the element. Numerical results are included.
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| 6. |
- Kalhori, S., et al.
(författare)
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Resonant ion-pair formation in electron collisions with rovibrationally cold H-3(+)
- 2004
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 69:2, s. 022713-
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Tidskriftsartikel (refereegranskat)abstract
- Experimental and theoretical cross sections for the resonant ion-pair formation (RIP) in electron collisions with rovibrationally cold H-3(+) ions are presented. Absolute cross sections for the RIP process producing H- ions are measured for center-of-mass energies between 2-20 eV using the CRYRING, heavy-ion storage ring. Theoretical cross sections are obtained using wave-packet propagation on both one- and two-dimensional models of relevant diabatic-potential energy surfaces and couplings of H-3(+) and H-3.
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| 7. |
- Larson, Jonas, et al.
(författare)
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Dynamics of a Raman coupled model: entanglement and quantum computation
- 2004
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Ingår i: Journal of Modern Optics. - 0950-0340 .- 1362-3044. ; 51:11, s. 1691-1704
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of a Raman coupled three-level Lambda atom with two quantized cavity modes is studied in the large detuning case; i.e. when the upper atomic level can be adiabatically eliminated. Particularly the situation when the two modes are prepared in initial coherent or squeezed states, with a large average number of photons, is investigated. It is found that the atom, after specific interaction times, disentangles from the two modes, leaving them, in certain cases, in entangled Schrodinger cat states. These disentanglement times can be controlled by adjusting the ratio between average numbers of photons in the two modes. It is also shown how this effective model may be used for implementing quantum information processing. Especially it is demonstrated how to generate various entangled states, such as EPR and GHZ states, and quantum logic operations, such as the control-not and the phase gate.
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| 8. |
- Liu, Y. Q., et al.
(författare)
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Eddy-current computations using adaptive grids and edge elements
- 2002
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Ingår i: IEEE transactions on magnetics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9464 .- 1941-0069. ; 38:2, s. 449-452
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented from eddy-current computations using adaptive techniques, based on rigorous a posteriori error estimates. The adaptivity restores the quadratic convergence with grid size of the magnetic energy, despite singularities occurring at corners. A new procedure is introduced to satisfy the solvability condition for the curl-curl equation. The methods are applied to a model of a hydrogenerator, with anisotropic conductivity and permeability. The ungauged formulation with both vector and scalar potentials gives very significant improvements in rate of convergence for this problem. Reasons for the improved convergence are discussed.
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| 9. |
- Vasan, Ramachandran S, et al.
(författare)
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Relations of serum aldosterone to cardiac structure : gender-related differences in the Framingham Heart Study.
- 2004
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Ingår i: Hypertension. - 1524-4563. ; 43:5, s. 957-62
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Tidskriftsartikel (refereegranskat)abstract
- Aldosterone is associated with myocardial fibrosis in experimental studies and with left ventricular remodeling in heart failure patients. We hypothesized that aldosterone influences ventricular remodeling in people without congestive heart failure in the community. We examined the relations between serum aldosterone and echocardiographic left ventricular measurements in 2820 Framingham Study subjects (mean age 57 years, 58% women, 88% white) free of myocardial infarction and overt heart failure. Serum aldosterone levels were higher in women compared with men. In linear regression models (adjusted for age, systolic blood pressure, weight, height, diabetes, heart rate, hypertension treatment, and ethnicity), left ventricular wall thickness and relative wall thickness were positively related, and left ventricular diastolic dimensions were inversely related to serum aldosterone in women (P<0.05 for all), but not in men (P>0.20 for all). There was no effect modification of the relations observed in women by menopausal status. The gender-related differences in relations of serum aldosterone to relative wall thickness were consistent across subgroups defined on the basis of sex-specific median values of systolic blood pressure and body mass index. Fractional shortening, left ventricular mass, and left atrial dimensions were not related to serum aldosterone in either sex. In conclusion, in our community-based sample of individuals free of myocardial infarction and heart failure, serum aldosterone was positively associated with a left ventricular geometric pattern suggestive of concentric remodeling (increased left ventricular wall thickness and relative wall thickness but decreased internal dimensions) in women but not in men. Additional investigations are warranted to confirm these findings.
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