| 4961. |
- Johansson, Carl-Christer, et al.
(författare)
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Population pharmacokinetic modeling and deconvolution of enantioselective absorption of eflornithine in the rat.
- 2013
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Ingår i: Journal of pharmacokinetics and pharmacodynamics. - : Springer Science and Business Media LLC. - 1573-8744 .- 1567-567X. ; 40:1, s. 117-28
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Tidskriftsartikel (refereegranskat)abstract
- Enantioselective pharmacokinetics and absorption of eflornithine in the rat was investigated using population pharmacokinetic modeling and a modified deconvolution method. Bidirectional permeability of L- and D-eflornithine was investigated in Caco-2 cells. The rat was administered racemic eflornithine hydrochloride as a single oral dose [40-3,000 mg/kg bodyweight (BW)] or intravenously (IV) (100-2,700 mg/kg BW infused over 60-400 min). Serial arterial blood samples were collected and L- and D-eflornithine were quantitated with a previously published chiral bioanalysis method. The D:L concentration ratio was determined in rat faeces. Intravenous L-and D-eflornithine plasma concentration-time data was analyzed using population pharmacokinetic modeling and described with a 3-compartment pharmacokinetic model with saturable binding to one of the peripheral compartments. Oral plasma concentration-time data was analyzed using a modified deconvolution method accounting for nonlinearities in the eflornithine pharmacokinetics. Clearance was similar for both enantiomers (3.36 and 3.09 mL/min). Oral bioavailability was estimated by deconvolution at 30 and 59% for L- and D-eflornithine. The D:L concentration ratio in feces was 0.49 and the Caco-2 cell permeability was similar for both enantiomers (6-10 × 10(-8) cm/s) with no evident involvement of active transport or efflux. The results presented here suggest that the difference in the bioavailability between eflornithine enantiomers is caused by a stereoselective difference in extent rather than rate of absorption. The presented modified deconvolution method made it possible to account for the non-linear component in the suggested three-compartment pharmacokinetic model thus rapidly estimating eflornithine oral bioavailability.
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| 4962. |
- Johansson, Christian, 1985, et al.
(författare)
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Endoscopy on SL2-eigenvarieties
- 2024
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Ingår i: Journal fur die Reine und Angewandte Mathematik. - 1435-5345 .- 0075-4102. ; 2024:813, s. 1-79
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we study p -adic endoscopy on eigenvarieties for <> SL 2 \mathrm{SL}_{2} over totally real fields, taking a geometric perspective. We show that non-automorphic members of endoscopic L -packets of regular weight contribute eigenvectors to overconvergent cohomology at critically refined endoscopic points on the eigenvariety, and we precisely quantify this contribution. This gives a new perspective on and generalizes previous work of the second author. Our methods are geometric, and are based on showing that the <> SL 2 \mathrm{SL}_{2} -eigenvariety is locally a quotient of an eigenvariety for <> GL 2 \mathrm{GL}_{2}, which allows us to explicitly describe the local geometry of the <> SL 2 \mathrm{SL}_{2} -eigenvariety. In particular, we show that it often fails to be Gorenstein.
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| 4963. |
- Johansson, Christian, et al.
(författare)
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Extended eigenvarieties for overconvergent cohomology
- 2019
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Ingår i: Algebra & Number Theory. - : Mathematical Sciences Publishers. - 1937-0652 .- 1944-7833. ; 13:1, s. 93-158
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Tidskriftsartikel (refereegranskat)abstract
- Recently, Andreatta, Iovita and Pilloni constructed spaces of overconvergent modular forms in characteristic p, together with a natural extension of the Coleman-Mazur eigencurve over a compactified (adic) weight space Similar ideas have also been used by Liu, Wan and Xiao to study the boundary of the eigencurve. This all goes back to an idea of Coleman. In this article, we construct natural extensions of eigenvarieties for arbitrary reductive groups G over a number field which are split at all places above p. If G is GL(2)/Q, then we obtain a new construction of the extended eigencurve of Andreatta-Iovita-Pilloni. If G is an inner form of GL(2) associated to a definite quaternion algebra, our work gives a new perspective on some of the results of Liu-Wan-Xiao. We build our extended eigenvarieties following Hansen's construction using overconvergent cohomology. One key ingredient is a definition of locally analytic distribution modules which permits coefficients of characteristic p (and mixed characteristic). When G is GL(n) over a totally real or CM number field, we also construct a family of Galois representations over the reduced extended eigenvariety.
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| 4964. |
- Johansson, Christian, et al.
(författare)
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Irreducible components of extended eigenvarieties and interpolating Langlands functoriality
- 2019
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Ingår i: Mathematical Research Letters. - 1073-2780 .- 1945-001X. ; 26:1, s. 159-201
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Tidskriftsartikel (refereegranskat)abstract
- We study the basic geometry of a class of analytic adic spaces that arise in the study of the extended (or adic) eigenvarieties constructed by Andreatta-Iovita-Pilloni, Gulotta and the authors. We apply this to prove a general interpolation theorem for Langlands functoriality, which works for extended eigenvarieties and improves upon existing results in characteristic 0. As an application, we show that the characteristic p locus of the extended eigenvariety for GL(2)/F, where F/Q is a cyclic extension, contains non-ordinary components of dimension at least [F : Q].
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| 4965. |
- Johansson, Christian, et al.
(författare)
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Local Langlands correspondence in rigid families
- 2020
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Ingår i: Pacific Journal of Mathematics. - : Mathematical Sciences Publishers. - 0030-8730 .- 1945-5844. ; 304:1, s. 65-102
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Tidskriftsartikel (refereegranskat)abstract
- We show that local-global compatibility (at split primes) away from p holds at all points of the p-adic eigenvariety of a definite n-variable unitary group. We do this by interpolating the local Langlands correspondence for GL(n) across the eigenvariety by considering the fibers of its defining coherent sheaf. We employ techniques of Chenevier and Scholze used in Scholze's proof of the local Langlands conjecture for GL(n).
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| 4966. |
- Johansson, Christian, 1985, et al.
(författare)
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PARALLEL WEIGHT 2 POINTS on HILBERT MODULAR EIGENVARIETIES and the PARITY CONJECTURE
- 2019
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Ingår i: Forum of Mathematics, Sigma. - : Cambridge University Press (CUP). - 2050-5094. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Let F be a totally real field and let p be an odd prime which is totally split in F. We define and study one-dimensional ‘partial’ eigenvarieties interpolating Hilbert modular forms over F with weight varying only at a single place v above p. For these eigenvarieties, we show that methods developed by Liu, Wan and Xiao apply and deduce that, over a boundary annulus in weight space of sufficiently small radius, the partial eigenvarieties decompose as a disjoint union of components which are finite over weight space. We apply this result to prove the parity version of the Bloch–Kato conjecture for finite slope Hilbert modular forms with trivial central character (with a technical assumption if [F : Q] is odd), by reducing to the case of parallel weight 2. As another consequence of our results on partial eigenvarieties, we show, still under the assumption that p is totally split in F, that the ‘full’ (dimension 1 + [F : Q]) cuspidal Hilbert modular eigenvariety has the property that many (all, if [F : Q] is even) irreducible components contain a classical point with noncritical slopes and parallel weight 2 (with some character at p whose conductor can be explicitly bounded), or any other algebraic weight.
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| 4967. |
- Johansson, Christian, et al.
(författare)
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Vox Populi, Vox Dei? Tacit collusion in politics
- 2023
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Ingår i: Economics & Politics. - : John Wiley & Sons. - 0954-1985 .- 1468-0343. ; 35:3, s. 752-72
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Tidskriftsartikel (refereegranskat)abstract
- We study competition between political parties in repeated elections with probabilistic voting. This model entails multiple equilibria, and we focus on cases where political collusion occurs. When parties hold different opinions on some policy, they may take different policy positions that do not coincide with the median voter's preferred policy platform. In contrast, when parties have a mutual understanding on a particular policy, their policy positions may converge (on some dimension) but not to the median voter's preferred policy. That is to say, parties can tacitly collude with one another, despite political competition. Collusion may collapse, for instance, after the entry of a new political party. This model rationalizes patterns in survey data from Sweden, where politicians on different sides of the political spectrum take different positions on economic policy but similar positions on refugee intake-diverging from the average voter's position, but only until the entry of a populist party.
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| 4968. |
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| 4969. |
- Johansson, Daniel, 1975
(författare)
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Economics vs. Physical-based Metrics for Relative Greenhouse Gas Valuations
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A range of alternatives to the Global Warming Potential (GWP) have been suggested in the scientific literature. One of these alternative metrics that has received significant attention is the cost-effective relative valuation of greenhouse gases. However, this metric is based on complex optimising integrated assessment models that are far from transparent to the general scientist or policymaker. Here we present a new analytic metric, the Cost-Effective Temperature Potential (CETP) which is based on an approximation of the cost-effective relative valuation. We show that this metric shares many similarities with the purely physical metric, Global Temperature change Potential (GTP), but that the CETP performs much better as an approximation to the cost-effective relative valuation.
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| 4970. |
- Johansson, Daniel, 1975, et al.
(författare)
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Equilibrium climate sensitivity in light of observations over the warming hiatus
- 2015
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Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 5:5, s. 449-453
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Tidskriftsartikel (refereegranskat)abstract
- A key uncertainty in projecting future climate change is the magnitude of equilibrium climate sensitivity (ECS), that is, the eventual increase in global annual average surface temperature in response to a doubling of atmospheric CO2 concentration. The lower bound of the likely range for ECS given in the IPCC Fifth Assessment Report (AR5; refs 1,2) was revised downwards to 1.5 degrees C, from 2 degrees C in its previous report(3), mainly as an effect of considering observations over the warming hiatus-the period of slowdown of global average temperature increase since the early 2000s. Here we analyse how estimates of ECS change as observations accumulate over time and estimate the contribution of potential causes to the hiatus. We find that including observations over the hiatus reduces the most likely value for ECS from 2.8 degrees C to 2.5 degrees C, but that the lower bound of the 90% range remains stable around 2 degrees C. We also find that the hiatus is primarily attributable to El Nino/Southern Oscillation-related variability and reduced solar forcing.
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