Seminars

Seminar at 14:00 room U02-102

The presentation will be given by Kert Tamm, Researcher from Laboratory of Solid Mechanics 

"Modelling of mechanical waves in a myelinated axon"

Abstract: Experimental studies have demonstrated that the signals in nerves have not only electrical components but are accompanied by mechanical and thermal effects as well. A brief overview is given about the previously established model framework for describing a combined nerve signal composed of electrical, mechanical and thermal components propagating on an unmyelinated axon followed by a more recent work done to account for an influence a myelin sheath might have on a mechanical component of such a signal ensemble.

Seminar at 14:00 room U02-102

The presentation by Heiko Herrmann, Senior Researcher from Laboratory of Solid Mechanics 

"Fiber Concrete: Experiments, Analysis, Simulation"

Seminar at 14:00 room U02-102

The presentation by Jaan Janno, a Tenured Full Professor from Division of Mathematics 

"On inverse problems that use nonlocality of fractional derivatives"

Seminar at 14:00 

The presentation by Marko Vendelin, a Tenured Full Professor from Laboratory of Systems Biology 

"Biophysics of the heart: overview of our studies on intracellular processes and the links between them"

Abstract: A brief overview of the studies performed in the Laboratory of Systems Biology on heart bioenergetics, mechanics, and electrophysiology. In particular, we look into how mitochondria respond to changes in the energy demand of the heart, diffusion within the cell, and how disruption of energy transfer within the cell disturbs other processes. Examples from the earlier and current studies will be given and overall aim described.

Seminar at 14:00 in room U02-102.

The presentation by Jaan Kalda, Tenured Full Professor from the Division of Physics

ETAG grant COVSG22 "Modelling the spread of a virus over scale-free networks: a key to understanding the role of superspreaders by COVID-19 pandemics"

Seminar at 14:00 in room U02-102.

The presentation by Sadia Sadique, Early Stage Researcher at the Division of Mathematics

"A single far-field pattern determines the shape of scattering screens"

Abstract: Scattering of acoustic waves from thin object called screen leads to the mathematical description of Helmholtz equation with boundary condition. Similarly, scattering of one dimensional curved screen in two dimensional plane determines its shape uniquely.

Seminar at 14:00 in room U02-102.

The presentation by Riho Rästa, a doctoral student from NICPB

"Magnetic order in square cupola compounds A(BO)Cu4(PO4)4 (AB = PTi, SrTi, KNb)"

In the upcoming presentation on 20.01.2022 14:00 at U02-102 I will talk about our recent research on the newly discovered isostructural compounds A(BO)Cu4(PO4)4 (AB = PTi, SrTi, KNb). The structure consists of square cupolas of magnetic Cu2+ ions that produce quadrupole interaction which allows for the appearance of the magnetoelectric (ME) effect. The ME effect has many potential future applications. In order to reveal the underlying mechanism of how the magnetic environments form in these systems we present a 63,65Cu and 31P NMR study.

Seminar at 14:00 in room U02-102.

The presentation will be given by Marco Patriarca, Senior Researcher from NICPB
"Hubs, diversity, and noise in FitzHugh-Nagumo oscillator networks: Synchronization and Resonances."

Abstract: Using the stochastic FitzHugh-Nagumo equations to represent the oscillatory electrical behavior of β-cells, we develop a coupled oscillator network model with cubic lattice topology. The emergence of pacemakers or hubs in the system is shown to be a natural consequence of oscillator population diversity [1]; we study also the effect of adding noise and the combined effects of diversity on the global behavior of the oscillator network and its resonant response. [1] S. Scialla, A. Loppini, M. Patriarca, and E. Heinsalu, Phys. Rev. E 103, 052211 (2021)

A hybride-seminar was held at the Institute of Cybernetics on Tuesday, November 9, at 11 am

Speaker:
Dr Serge Dos Santos, Associate Professor Hab. Dir. Rech.
INSA Centre Val de Loire, Inserm iBrain, Blois, France
Vice-President of Academia NDT International
Director of the IIAV (2018-2022)

Title: "Acoustic Nonlinear Imaging within NDT 4.0 Using Prescriptive Signal and Data Analysis"

Room CYB101, Akadeemia street 21

Seminar at 14:00 in room U04-103.

The presentation will be given by Nele Reimets, a doctoral student from NICPB
"Developing analytical applications for parahydrogen hyperpolarization: urinary elimination pharmacokinetics of nicotine"

Pharmacokinetics (PK) is essential in modern drug development in order to understand the (bio)chemical processes that a drug undergoes in the body from its intake to excretion. To follow minute concnetrations of analytes in complex mixtures like urine or blood, exceptional resolution and sensitivity is desired. Nuclear magnetic resonance spectroscopy (NMR) is an attractive choice for PK for it offers straightforward data interpretation and quantitative analysis. However, pharmacologically active compounds and their metabolites in biofluids often appear in minute concentrations, well below the detection limit of NMR. To improve the NMR sensitivity parahydrogen (pH2) hyperpolarization (HP) has been adapted for measuring biofluids [1]. Recent progress in pH2 HP techniques allows multiscan experiments [2], [3] and to resolve complex spectra of urine with 2D spectroscopy [4]. By combining pH2 HP and 2D spectroscopy, it is possible to overcome the NMR sensitivity barrier and detect midnanomolar concentrations of a drug and a drug metabolite in a biofluid matrix [5]. In this presentation, I will discuss how pH2 HP can be applied in pharmacokinetics where precise quantitative and qualitative analysis is desired. As a proof of concept, we measured urine of humans exposed to nicotine and compared two common intake methods – smoking and absorption through skin by using a transdermal patch. We followed urinary elimination of nicotine, and its main metabolite cotinine, and determined their concentrations in urine during the onset and withdrawal from nicotine consumption. REFERENCES [1] I. Reile, N. Eshuis, N. K. J. Hermkens, B. J. A. van Weerdenburg, M. C. Feiters, F. P. J. T. Rutjes, M. Tessari, Analyst 2016, 141, 4001–4005. [2] N. Eshuis, R. L. E. G. Aspers, B. J. A. van Weerdenburg, M. C. Feiters, F. P. J. T. Rutjes, S. S. Wijmenga, M. Tessari, Angew. Chemie Int. Ed. 2015, 54, 14527–14530. [3] N. K. J. Hermkens, N. Eshuis, B. J. A. van Weerdenburg, M. C. Feiters, F. P. J. T. Rutjes, S. S. Wijmenga, M. Tessari, Anal. Chem. 2016, 88, 3406–3412. [4] L. Sellies, I. Reile, R. L. E. G. Aspers, M. C. Feiters, F. P. J. T. Rutjes, M. Tessari, Chem. Commun. 2019, 55, 7235–7238. [5] N. Reimets, K. Ausmees, S. Vija, I. Reile, Anal. Chem. 2021 93, 9480-9485.

Project title: Experiments in physics teaching and learning

In cooperation with Leibnic University Hannover (Germany), Tallinn University of Technology (Estonia), University of Latvia (Latvia)

Schedule

7. oktoober 2021

8. oktoober 2021

Full program in Tallinn

This project of the Baltic-German University Liaison Office is supported by the German Academic Exchange Service (DAAD) with funds from the Foreign Office of the Federal Republic Germany.

Seminar at 14:00 in room U02-102.

The presentation will be given by Riho Rästa, a doctoral student from NICPB

"Nuclear magnetic resonance of the square cupola compounds A(BO)Cu_4(PO_4)_4 (AB = BaTi, SrTi, PbTi, KNb)"

In the upcoming presentation on 30.09.2021 14:00 at U02-102 I will talk about the history and discovery of the magnetoelectric (ME) effect and I will explain the contributing conditions like broken space-time symmetry, spiral driven ordering and geometric frustration. Researchers in Japan (Kimura et al. [1]) have been successful in synthesizing new crystals that exhibit the ME effect in a previously unseen manner. The A(BO)Cu4(PO4)4 compunds comprise of magnetic Cu2+ ions that form so-called square cupola clusters. By cooling the compound we observe a phase shift under the temperature T = 10 K into an antiferromagnetic ordered state. In the overview I will first go through the main characteristics that have been found and then I will focus on the studies made using nuclear magnetic resonance techniques. I will introduce the two main articles, published by Islam et al. [2] and by our own team (Rästa et al. [3]). This will be the first presentation of two, in the next presentation I will talk about my current work involving the expansion of these studies.

References

[1] K. Kimura, P. Babkevich, M. Sera, M. Toyoda, K. Yamauchi, G. S. Tucker, J. Martius, T. Fennell, P. Manuel, D. D. Khalyavin, R. D. Johnson, T. Nakano, Y. Nozue, H. M. Rønnow, and T. Kimura. Magnetodielectric detection of magnetic quadrupole order in Ba(TiO)Cu4(PO4)4 with Cu4O12 square cupolas. Nature Communications, 7:13039, October 2016.

[2] S. S. Islam, K. M. Ranjith, M. Baenitz, Y. Skourski, A. A. Tsirlin, and R. Nath. Frustration of square cupola in sr(tio)cu4(po4)4. Phys. Rev. B, 97:174432, May 2018.

[3] Riho Rästa, Ivo Heinmaa, Kenta Kimura, Tsuyoshi Kimura, and Raivo Stern. Magnetic structure of the square cupola compound ba(tio)cu4(po4)4. 101:054417.

Seminar at 14:00 in room U02-102.

The presentation will be given by Maris Eelsalu, Researcher at The Laboratory of Wave Engineering
"Sandy beach evolution in the low-energy microtidal Baltic Sea: attribution of changes to hydrometerological forcing"

The focus is on the evolution of two sandy beaches (Pirita and Russalka) in Tallinn Bay, northeastern Baltic Sea, that are about 3 km apart and oriented differently. A large proportion of annual wave energy flux is packed into a very few days in the year. The wind direction and thereby the direction of the wave fields of the strongest storms in the year determines which coastal areas are most affected. The response of the beaches to hydrometeorological conditions over 12 years, 2008–2020 based on annual high-resolution measurements using airborne and terrestrial laser scanning technology is quantified. The fastest sediment removal from the subaerial beach occurs during time periods with elevated water level and strong waves. Accretion occurs during periods when water level is less elevated. Even though annual variations in the sand volume of subaerial beach are significant, both beaches are stable but respond differently. A comparison of the link between volume changes of the beaches with the monthly average intensity of hydrometeorological drivers suggests a specific mechanism that supports one of the beaches. Sand that is removed from the higher part of Pirita beach and moved to the south and deposited in the shallow nearshore during elevated water levels and north-western storms is transported back to the north in very shallow water during periods of low water level and moderate south-western winds. This mechanism may implicitly stabilise the beaches under bi-directional wind regime.

Seminar at 14:00 in room U02-102

The presentation was given by Martin Laasmaa, Senior Researcher at the Laboratory of Systems Biology
"Investigating calcium handling proteins in heart cells by employing super-resolution imaging"

Heart failure, and cardiovascular disease in general, continue to be the leading cause of morbidity and mortality. Despite some advancements in cardiac research, the prevalence of cardiac diseases continues to grow as the population age. Thus, the already massive socioeconomic burden presented by cardiovascular disease is only expected to increase.
The heart cell's contraction is regulated through changes in intracellular calcium concentration, controlled by different calcium handling proteins. During heart diseases, function, arrangement, and quantity of these proteins are altered, resulting in reduced heart blood pumping capacity. However, in the past decades, advancements in optical microscopy have been made, making it a suitable tool for investigating the molecular mechanisms underlying these alterations. This talk will focus on studying ryanodine receptors, one of the most prominent calcium-handling proteins in heart cells, at nanoscale resolution using different super-resolution imaging methods.

Seminar at 14:00 in Zoom

The presentation was given by Heiko Herrmann, Senior Researcher at the Laboratory of Solid Mechanics
"Composites with inclusions: orientation averaging for rod-like and orthotropic inclusions"

Seminar at 14:00 in room U02-102

The presentation was given by:

1. Nataliia Kinash, Early Stage Researcher of the Department of Cybernetics
"Inverse problems for generalized subdiffusion equations"

2. Mart Ratas,Early Stage Researcher of the Department of Cybernetics
"Haar wavelet based numerical methods: employing adaptive grids"

Seminar at 14:00 in room U05-103

The presentation was given by Jüri Kurvits, Lecturer at the Division of Mathematics and Marina Kurvits (Tallinn University)
"Kuidas tudeng õpib ja mõtleb ning kuidas teda selles toetada?"

Seminar at 14:00 in room U02-102

The presentation was given by Kevin Parnell, Research Professor at the Laboratory of Wave Engineering
"Bridging gaps between coastal science and coastal management"

Seminar at 14:00 in room U02-102

The presentation was given by Kert Tamm, Researcher at the Laboratory of Solid Mechanics
"Mathematical Modelling of Nerve Signals"

Contemporary systems biology is using widely in silico modelling of biological processes. The fascinating problem of propagation of complex signals in nerve fibres can also be analysed in such a way. The complexity of this process is characterized by the ensemble of waves which is composed by electrical, mechanical and thermal signals in fibres. This reflects the physical complexity of physiological processes. In this talk it is argued how to build up a mathematical model by uniting the equations which govern single waves in structural elements of a fibre into a coupled system. As a proof of concept such a model is presented in which the process is triggered by an electrical impulse following the classical axon physiology. The discussion about modelling is going on concentrating upon the physiological properties biomembranes and bulk matter and what is the most important problem – the character of coupling forces. The numerical simulations help to analyze the coupling effects and causal mechanisms.

Seminar at 14:30 in room U02-102

The presentation was given by Gionni Marchetti , National Institute of Chemical Physics and Biophysics
"A Bayesian approach to Naming Game model"

We present a novel Bayesian approach to semiotic dynamics, which is a cognitive analogue of the naming game model restricted to two conventions. The one-shot learning that characterizes the agent dynamics in the basic naming game is replaced by a word-learning process, in which agents learn a new word by generalizing from the evidence garnered through pairwise-interactions with other agents. The principle underlying the model is that agents, like humans, can learn from a few positive examples and that such a process is modeled in a Bayesian probabilistic framework. We show that the model presents some analogies but also crucial differences with respect to the dynamics of the basic two-convention naming game model. The model introduced aims at providing a starting point for the construction of a general framework for studying the combined effects of cognitive and social dynamics.

Seminar at 14:30 in room U02-102

The presentation was given by Dmitri Kartofelev, Researcher at the Laboratory of Solid Mechanics
"Fractal geometry of music"

A general discussion on fractal geometry present in human composed music and its applications.

Seminar at 14:30 in room U02-102

The presentation was given by Gert Tamberg, Senior Lecturer at the Division of Mathematics
"Sampling operators"

Seminar at 14:30 in room U02-102

The presentation was given by Jaan Kalda, Professor at the Division of Physics
"Universal law for distribution of records"

It will be shown that almost all the ranking lists related to human achievements (e.g. seasonal bests of 100 meters running race) are described by a universal distribution law: numerically described achievement x is a linear function of ra – the rank r taken to a certain power a, with 0<a≤2. This linear law can be extrapolated to the values of r approaching zero, making it possible to estimate, what would be the result of the winner of the race if the selection base were to be much larger than it currently is. In the case of the 100 meters race, such an extrapolation results in x=9.48 seconds, implying that at the current level of technology (running shoes, dietary prescriptions, etc), this is the human limit.
It will be hypothesized that such a law is the result of a quasi-homogeneous distribution of humans over a "fitness space".

Seminar at 14:00 in room U02-102

The presentation was given by Jüri Majak, Professor at the Department of Mechanical and Industrial Engineering

Seminar at 14:00 in room U02-108

The presentation was given by Arvo Mere, Associate Professor Division of Physics
"Õppeainele e-toe loomine Moodle-keskkonnas"

Seminar at 16:00 in room CYB-B101

The presentation was given by Jüri Engelbrecht
"Pool sajandit mehaanikat"

Seminar at 14:00 in room U02-102

The presentation was given by Aleksei Tepljakov Research Scientist Department of Computer Systems
"On the Recent Developments in Fractional-order Modeling and Control and Virtual Reality in the Centre for Intelligent Systems"

Seminar at 14:00 in room U02-102

The presentation was given by Stephanie Rendon de la Torre Engineering physics PhD Student
"Multifractal and fractal complex networks: Estonian network of payments"

Seminar at 11:00 in room CYB-B101

The presentation was given by Dr. Robinson Hordoir Swedish Meteorological and Hydrological Institute (SMHI), Sweden
"Nemo-Nordic: A NEMO based ocean model for Baltic & North Seas, research and operational applications"

Nemo-Nordic, a Baltic & North Sea three-dimensional hydrodynamic is presented. This model is intended to come as a tool for both short term and long term simulations that can be used for ocean forecasting as well as process and climatic studies. A brief overview of the model and its research and operational capabilities shall be described by its main developer Dr. Robinson Hordoir, from the Swedish Meteorological and Hydrological Institute, Sweden.

Seminar at 14:00 in room CYB-B101

The presentation was given by Dušan Gabriel the Institute of Thermomechanics of the Czech Academy of Sciences
"Explicit contact-impact algorithm based on the bipenalty method"

Seminar at 10:00 in room CYB-B101

The presentation was given by:

1) Jaak Monbaliu, Department of Civil Engineering, Faculty of Engineering Science, University of Leuven, Belgium
"Climate REsilient coaST"

2) Hannes Tõnisson, Institute of Ecology, School of Natural Sciences, Tallinn University, Estonia
"Storminess, extreme storms and coastal processes - today, in the past and tomorrow"

3) Magnus Larson, Environmental Technology, Faculty of Engineering, Lund University, Sweden
"Modeling coastal evolution from an engineering perspective"