Gjesteforelesninger og seminarer - Side 7
The survival of green plants depends on the efficient use of photosynthesis in the leaves, where sunlight, water, and CO2 are transformed into sugar – the raw material, which builds up even the largest trees. The dissolved sugars are transported by osmosis through the sieve tubes of the phloem, a vascular system, which runs through the veins of the leaves and on through the stem, all the way down into the roots. The sugar production sites (mesophyll) are distributed over the entire leaf, and it is important for the functionality of the leaf that they are all able to export their sugars. For conifer needles the linear venation architecture makes this challenging, and they have an extra “transfusion tissue” that bridges between production and transport. We are currently studying this complex collection of interdigitated water -and sugar-carrying cells by micro X-ray tomography on intact needles and by network modelling, to understand the pathways for water and for sugars (running in opposite directions) with huge pressure differences (say 3 MPa) across tiny length scales (say 5 microns).
Thomas Bohr is Professor of Physics at the Physics Department of the Technical University of Denmark.
Diffusion and reactions are central to understanding life. However, studies often focus on dilute systems, while the interior of living cells is crowded with macromolecules that occupy about 20 % to 40 % of the cell volume, affecting virtually all intracellular processes [1]. In this talk, I will mainly focus on diffusion, emphasising the effects significant to crowded intracellular environments, such as polydispersity of crowders [2], macromolecular shapes, interactions [3], and softness [4]. We will also briefly discuss how reactions proceed under crowding, paying particular attention to enzymatic reactions [5] and the cooperativity of divalent binding [6].
Abstract (PDF)
Alexander Müller-Hermes will give a talk with title: Capacities of quantum channels
In 80s Weibel observed that K-theory is homotopy invariant on Fp-schemes up to p-torsion. His main tool was the action of the ring Witt vectors on nil-K-groups: NKi(R) = Ker(Ki(R[t]) → Ki(R)). We will revisit the proof and check that the same result holds for all finitary localizing invariants.
- Hva du ikke finner på EIOPAs sider
- Matematisk Institutt ved professor emeritus Erik Bølviken tilbyr et to-dagers etterutdanningskurs i Solvency II.
Stephen Hladky presents work in collaboration with Margery A. Barrand (both Department of Pharmacology, University of Cambridge).
Abstract: Extravascular fluxes of marker substances and some wastes are sufficiently fast that there is almost certain to be a component of flow augmenting their diffusion in the parenchyma. There have been two major proposals for how this flow is produced and where it is important. The evidence for the classical and glymphatic hypotheses will be reviewed. Extravascular, and in particular perivascular, routes for fluid movement out of the parenchyma to lymphatics may be important in the development of hydrocephalus.
I will explain how motivic homotopy theory can be used to attack problems regarding finite projective modules over smooth affine k-algebras. I will recall in particular the foundational theorem of Morel and Asok-Hoyois-Wendt, and the construction of the Barge-Morel Euler class. Time permitting, I will explain recent progress on Murthy's splitting conjecture.
C*-algebra seminar talk by Marco Matassa (OsloMet)
Financial risk arising from the increasing of life expectancy. This is all in a nutshell. To know more, come to the lecture: forecasting, modelling, quantification.
We combine a systematic approach for deriving general a posteriori
error estimates for convex minimization problems using convex duality relations with a recently derived generalized Marini formula. The resulting a posteriori error estimates are essentially constant-free and apply to a large class of variational problems including the p-Dirichlet problem, as well as degenerate minimization, obstacle and image de-noising problems.
For the p-Dirichlet problem, the a posteriori error bounds are equivalent to the classical residual type a posteriori error bounds and, hence, reliable and efficient.
Abstract (PDF)
José Carlos Nieto Borge is a marine physicist and associate professor at the Universidad de Alcalá de Henares, Spain.
We consider the linearized elasticity equations, discretized using multi-patch Isogeometric Analysis. To solve the resulting linear system, we choose the Dual-Primal Isogeometric Tearing and Interconnecting (IETI-DP) Method with a scaled Dirichlet preconditioner. We are interested in a convergence analysis. See more details below.
We will present the results of numerical experiments that demonstrate our theoretical findings.
Professor Elaine Cohen (University of Utah) kreeres til æresdoktor ved UiO. I den forbindelse vil hun holde en forelesning: Mathematics and Geometric Modeling: Similar Ingredients, Distinct Goals.
I will discuss the question in the title. This is joint work with Alex Degtyarev and Ilia Itenberg. This will be a talk involving very classical topics in algebraic geometry. I will try to make the talk accessible to students at master- and PhD level.
QOMBINE seminar by Daniel Stilck Franca (ENS Lyon)
C*-algebra seminar talk by Pinhas Grossman (University of New South Wales)
The simulation of multi-phase fluids has attained growing interest in the last decades. While for single-phase flow with the Navier-Stokes system the basic model is well understood, for multi-phase systems additional challenges by the necessity to track the transition zones or interfaces between different fluid components arise.
We propose to use a phase field as a smooth indicator function to describe this situation. Using phase-field models, one introduces a small layer of mixed fluids as a so-called diffuse interface. One benefit of phase-field models is, that they can naturally deal with topology changes and can easily be extended to cope with contact line dynamics.
This model allows for discussing the optimal control problem for two-phase flow. We introduce a thermodynamically consistent phase-field model for two-phase flow including a model for contact line dynamics and introduce an energy stable numerical scheme.
This scheme allows us to investigate the time-discrete (open loop) optimal control problem, where we investigate different control actions to steer a given distribution of phases towards the desired distribution. We derive the existence of solutions to the optimal control problem and provide first-order optimality conditions.
Hybrid format via Zoom possible on demand (contact timokoch at uio.no)