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INTRODUCTION
The aim of the SIJIMAT seminar is to bring together young researchers from the Centre de Recerca Matemàtica in order to promote the interaction between the different research areas present at the centre. Through informal talks of 45 minutes plus a 15 minutes discussion, PhD students and postdoctoral fellows will have the opportunity to learn about the research done by their colleagues.
All talks are expected to have an introductory section that helps non-expert participants understand the main questions and goals of the field in which the speaker works. A second section might introduce the main tools used by the speaker to tackle those questions. Finally, in the last section, the speaker will provide a brief summary of her current research project.
NEXT SESSION | 15/12/22
4D reconstruction of developmental trajectories using spherical harmonics
Date: Thursday 19th, January 2023.
Time: 12h
Place: Aula petita CRM.
Abstract: Normal organogenesis cannot be recapitulated in vitro for mammalian organs, unlike in species including Drosophila and zebrafish. Available 3D data in the form of ex vivo images only provide discrete snapshots of the development of an organ morphology. Here, we present a computer-based approach to recreate its continuous evolution in time and space from a set of 3D volumetric images. This method is based on the remapping of shape data into the space of the coefficients of a spherical harmonics expansion where a smooth interpolation over time is simpler. This approach had been tested on mouse limb buds and embryonic hearts. A key advantage of this method is that the resulting 4D trajectory can take advantage of all the available data while also being able to interpolate well through time intervals for which there are little or no data. This allows for a quantitative, data-driven 4D description of mouse limb morphogenesis.
SPEAKER
Giovanni Dalmasso
Postdoctoral Researcher at CRM
After getting my bachelor (2009) and master (2011) degrees in Mathematics for Engineering Sciences and Mathematical Engineering at the Polytechnic University of Turin I moved to the ETH of Zürich (Switzerland) in the Koumoutsakos lab where I completed my master thesis and worked as research assistant. Here I focused my research in swarming dynamics and collective behaviours using an agent-based modelling (ABM) approach on HPC frameworks based on reinforcement learning.
Afterwards (2012) I joined the Attinger lab at the Center of Environmental Research (UFZ) of Leipzig (Germany) where my main focus was to investigate the effects of the environment on T-lymphocyte cells differentiation. Additionally I was collaborating in the implementation of a computationally inexpensive sequential screening method able to reduce the number of parameters in environmental models.
In 2017 obtained my PhD in Biology at the University of Heidelberg working at the German Cancer Research Center (DKFZ) in the group of Anne Hamacher-Brady. My main project here consisted in using ABM to predict the role of mitochondria in the interplay of autophagy and apoptosis.
In 2017 I joined as PostDoc the Sharpe lab in Barcelona (Spain) at the Centre for Genomic Regulation (CRG) which later the same year moved to the European Molecular Biology Laboratory (EMBL). Here I was working on the development of a mathematical method based on the concept of spherical harmonics which has created the first ever continuous numerical description of morphogenesis of the limb bud over time and space. Additionally, I deepened my biological knowledge and started doing experiments. Specifically, I began to be interested and working on the understanding of the formation of the vasculature inside the limb using an in vitro approach.
As of November 2022, I work at the Centre de Recerca Matematica (Bellaterra, Barcelona) where I joined the group of Tomas Alarcon.
PAST SESSIONS
15/12/22 | Alfonso Garmendia (CRM) | Deformation Quantization
ABSTRACT: The goal of quantization is to associate a C*-algebra (a quantum space) to any Poisson manifold (a classical space) in a way that preserves the symmetries. This talk tries to convey the motivation and a summary on deformation quantization with examples.
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01/12/22 | Angelica Torres (CRM) | Algebraic Geometry and line reconstruction in Computer Vision
ABSTRACT: The 3D image reconstruction problem aims to create a 3D model of a scene or object starting from 2D images. This process is done in four stages: Feature identification in the images, point and line matching, camera estimation and triangulation, and construction of the 3D model. Stages two and three of the process deal mainly with geometric information that can be studied algebraically. This is precisely where Algebraic Geometry comes into play. In this talk I will introduce the 3D image reconstruction problem and the algebraic tools that allow to model the cameras and image features, I will also define the point and line Multiview varieties, and finally mention some algebraic results on the geometry of points and lines that can be reconstructed effectively.
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18/11/22 | Mar Giralt-Miron (UPC) | Chaotic dynamics, exponentially small phenomena and Celestial Mechanics
ABSTRACT: A fundamental problem in dynamical systems is to prove that a given model has chaotic dynamics. One of the methods employed to prove this type of motions is to verify the existence of transversal intersections between the stable and unstable manifolds of certain objects. Then, there exists a theorem (the Smale-Birkhoff homoclinic theorem) which ensures the existence of chaotic motions.
In this talk we present a method to analyze the distance and transversality between certain stable and unstable manifolds when a small perturbation is added to an integrable system. In particular, we consider the case where the distance between manifolds is exponentially small. This implies that this difference cannot be detected by expanding the manifolds into a series with respect to the small perturbation parameter. Therefore, classical perturbation theory cannot be applied.
Finally, we apply these techniques to a celestial mechanics problem. In particular, we study the Lagrange point L 3 in the restricted planar circular 3-body problem.
organizers
| Giovanni Dalmasso | CRM Postdoctoral Researcher | Cancer Modelling Lab |  |
| Gerard Farré | CRM Postdoctoral Researcher | Dynamical Systems | |
| Roser Homs | CRM Postdoctoral Researcher | Computational & Mathematical Biology | |
| Manuel Molano | CRM Postdoctoral Researcher | Computational Neuroscience | |
