Past Events

[Seminar] Growth estimates for \(p-\)harmonic Green functions on weighted \(R^n\) and metric spaces | Professor Jana Björn, Linköping University and OIST TSVP Visiting Scholar

2024-05-15
L4E48 and Zoom

Speaker: Professor Jana Björn, Linköping University and OIST TSVP Visiting Scholar

Title: The Dirichlet Problem and Boundary Regularity for Nonlinear Parabolic Equations

Abstract: As shown by Serrin in 1964, the growth at an isolated singularity of solutions to the elliptic equation div A(x, ∇u) = 0 in Rn (including p-harmonic functions with p > 1) is exactly determined by the dimension n and the parameter p associated with the equation. In this talk, I will discuss growth and integrability properties for p-harmonic Green functions and their gradients on weighted Rn, with a p-admissible weight, as well as on complete metric spaces equipped with a doubling measure supporting a p-Poincar´e inequality. In these situations, the dimension n is replaced by the local growth of the underlying measure near the isolated singularity, and the obtained growth and integrability exponents are sharp.

【Seminar】The Dirichlet problem and boundary regularity for nonlinear parabolic equations | Prof. Professor Anders Björn, Linköping University and OIST TSVP Visiting Scholar

2024-05-08
L4E48 and Zoom

Speaker:  Professor Anders Björn, Linkoping University and OIST TSVP Visiting Scholar

Title: The Dirichlet problem and boundary regularity for nonlinear parabolic equations    

Abstract: The p-parabolic equation \[ \partial_t u = \Delta_p u := \dvg(|\nabla u|^{p-2}\nabla u) \] is a nonlinear cousin of the classical heat equation. As such, it offers both difficulties and advantages compared with the heat equation. In the talk, we consider the Perron method for solving the Dirichlet problem for the p-parabolic equation in general bounded domains in $R^{n+1}$. Compared to space-time cylinders, such domains allow the space domain to change in time. Of particular interest will be boundary regularity for such domains, i.e. whether solutions attain their boundary data in a continuous way. Relations between regular boundary points and barriers will be discussed, as well as some peculiar examples and surprising phenomena related to boundary regularity. Towards the end I will discuss the same type of questions for two other nonlinear cousins of the heat equation, the porous medium equation \[ \partial_t u = \dvg(u^m) \] and the so-called normalized p-parabolic equation \[ \partial_t u = |\nabla u|^{2-p}\Delta_p u. \] The talk is based on collaborations with Jana Bj\"orn (Link\"oping), Ugo Gianazza (Pavia), Mikko Parviainen (Jyv\"askyl\"a) and Juhana Siljander (Jyv\"askyl\"a).

TSVP Talk: "What Can Quantum Field Theory Teach Us About Black Holes (And Vice Versa)?" by Nick Dorey

2024-04-25
L5D23 and zoom

TSVP Talk
Language: English (no interpretation). Target audience: General audience / everyone at OIST and beyond. Freely accessible to all OIST members and guests without registration (also via Zoom).

TSVP Talk: "Spectra of Complex Networks" by Izaak Neri

2024-04-11
L4E48 and zoom

TSVP Talk
Language: English (no interpretation). Target audience: General audience / everyone at OIST and beyond. Freely accessible to all OIST members and guests without registration (also via Zoom).

[Seminar] Flows and Topological Changes During Tissue Morphogenesis

2024-04-08
OIST Lab1 B503 Seminar Room

Speaker: Professor Luiza Angheluta-Bauer, Condensed Matter Physics, University of Oslo

Hosted by Professor Mahesh Bandi Nonlinear and Non-equilibrium Physics Unit

Abstract:

Collective structural arrangements and cell migration are important physical processes underlying tissue development and regeneration. Understanding the complexity of cell-cell interactions and the emergence of collective behaviors at the tissue scale presents formidable challenges both experimentally and theoretically.

In this talk, I will discuss recent theoretical work on the dynamical patterns that emerge at the tissue scale from localized rearrangements and topological defects. Using a multi-phase field model, we demonstrate that tissue fluidity stems from cell neighbor exchanges, serving as transient sources of vortical flow. This flow emerges from the relative dispersion of cells at a rate proportional to the frequency of rearrangements. Balancing collective migration with relative cell motion appears to be essential for maintaining tissue shape and fluidity. Using a cell-based model, we study the tissue's response to the presence of a vortex. While solid-like behavior tends toward conical shapes, localized fluidization triggers the transition to a tube, which is fundamental in biological tissues.

"Unraveling global change impacts to biodiversity and ecosystem services with interdisciplinary approaches" by Laura Dee (TSVP Seminar)

2024-03-26
L5D23

Seminar, as part of Thematic Program on Response Diversity
Language: English (no interpretation). Target audience: Students and Researchers from related fields.
Freely accessible to all OIST members and guests without registration (also via Zoom).

"How can we measure the diversity of ecological interactions in the real world?" by Fredric Windsor (TSVP Seminar)

2024-03-22
L5D23

Seminar, as part of Thematic Program on Response Diversity
Language: English (no interpretation). Target audience: Students and Researchers from related fields.
Freely accessible to all OIST members and guests without registration (also via Zoom).

Panel Discussion: Publishing Science in a Rapidly Changing Publishing Landscape (with TSVP visitors)

2024-03-15
L4E48

Seminar, as part of Thematic Program on Response Diversity
Language: English (no interpretation). Target audience: General audience / everyone at OIST and beyond. Freely accessible to all OIST members and guests without registration (also via Zoom).

TSVP Talk: "Recruiting, Developing, and Retaining Excellent Researchers in the Faculty of Science at the University of Zurich" by Owen Petchey

2024-03-14
L5D23 and zoom

Seminar, as part of Thematic Program on Response Diversity
Language: English (no interpretation). Target audience: General audience / everyone at OIST and beyond. Freely accessible to all OIST members and guests without registration (also via Zoom).

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