DSpace Community:
https://dspace.lboro.ac.uk/2134/80
2017-03-29T17:09:26Z
2017-03-29T17:09:26Z
Ising model – an analysis, from opinions to neuronal states
Kusmartsev, Vassili F.
Zhang, Wu
Kusmartseva, Anna F.
Balanov, Alexander G.
Janson, Natalia B.
Kusmartsev, F.V.
https://dspace.lboro.ac.uk/2134/24569
2017-03-29T14:06:15Z
2017-01-01T00:00:00Z
Title: Ising model – an analysis, from opinions to neuronal states
Authors: Kusmartsev, Vassili F.; Zhang, Wu; Kusmartseva, Anna F.; Balanov, Alexander G.; Janson, Natalia B.; Kusmartsev, F.V.
Abstract: Here we have developed a mathematical model of a random
neuron network with two types of neurons: inhibitory and excitatory. Every
neuron was modelled as a functional cell with three states, parallel to
hyperpolarised, neutral and depolarised states in vivo. These either induce
a signal or not into their postsynaptic partners. First a system including just
one network was simulated numerically using the software developed in
Python.
Our simulations show that under physiological initial conditions, the
neurons in the network all switch off, irrespective of the initial distribution
of states. However, with increased inhibitory connections beyond 85%,
spontaneous oscillations arise in the system. This raises the question
whether there exist pathologies where the increased amount of inhibitory
connections leads to uncontrolled neural activity. There has been
preliminary evidence elsewhere that this may be the case in autism and
down syndrome [1-4].
At the next stage we numerically studied two mutually coupled networks
through mean field interactions. We find that via a small range of coupling
constants between the networks, pulses of activity in one network are
transferred to the other. However, for high enough coupling there appears a
very sudden change in behaviour. This leads to both networks oscillating
independent of the pulses applied. These uncontrolled oscillations may also
be applied to neural pathologies, where unconnected neuronal systems in
the brain may interact via their electromagnetic fields. Any mutations or
diseases that increase how brain regions interact can induce this
pathological activity resonance.
Our simulations provided some interesting insight into neuronal behaviour,
in particular factors that lead to emergent phenomena in dynamics of neural
networks. This can be tied to pathologies, such as autism, Down's syndrome,
the synchronisation seen in parkinson's and the desynchronisation seen in
epilepsy. The model is very general and also can be applied to describe
social network and social pathologies.
Description: This is a conference paper for ENEC 2016.
2017-01-01T00:00:00Z
Electric-field distribution in a quantum superlattice with an injecting contact: exact solution [original Russian text]
Maksimenko, V.A.
Makarov, V.V.
Koronovskii, Alexey A.
Hramov, Alexander E.
Venckevicius, R.
Valusis, G.
Balanov, Alexander G.
Kusmartsev, F.V.
Alekseev, K.N.
https://dspace.lboro.ac.uk/2134/24568
2017-03-29T13:19:55Z
2016-01-01T00:00:00Z
Title: Electric-field distribution in a quantum superlattice with an injecting contact: exact solution [original Russian text]
Authors: Maksimenko, V.A.; Makarov, V.V.; Koronovskii, Alexey A.; Hramov, Alexander E.; Venckevicius, R.; Valusis, G.; Balanov, Alexander G.; Kusmartsev, F.V.; Alekseev, K.N.
Abstract: A very simple model describing steady-state electron transport along a quantum superlattice of a finite length taking into account an arbitrary electrical characteristic of the injecting contact is considered. In the singleminiband approximation, exact formulas for the spatial distribution of the electric field in the superlattice are derived for different types of contact. Conditions under which the field is uniform are identified. Analytical expressions for the current–voltage characteristics are obtained. In the context of the developed theory, the possibility of attaining uniform-field conditions in a diode structure with a natural silicon-carbide superlattice is discussed.
Description: The text in the file to download is the original article in Russian. Russian Text © V.A. Maksimenko, V.V. Makarov, A.A. Koronovskii, A.E. Hramov, R. Venckevičius, G. Valušis, A.G. Balanov, F.V. Kusmartsev, K.N. Alekseev, 2016, published in Pis’ma v Zhurnal Eksperimental’noi i Teoreticheskoi Fiziki, 2016, Vol. 103, No. 7, pp. 527–532.
2016-01-01T00:00:00Z
Rough path properties for local time of symmetric α stable process
Wang, Qingfeng
Zhao, Huaizhong
https://dspace.lboro.ac.uk/2134/24537
2017-03-24T14:58:06Z
2017-01-01T00:00:00Z
Title: Rough path properties for local time of symmetric α stable process
Authors: Wang, Qingfeng; Zhao, Huaizhong
Abstract: In this paper, we first prove that the local time associated with symmetric α-stable processes is of bounded p-variation for any View the MathML source partly based on Barlow’s estimation of the modulus of the local time of such processes. The fact that the local time is of bounded p-variation for any View the MathML source enables us to define the integral of the local time View the MathML source as a Young integral for less smooth functions being of bounded q-variation with View the MathML source. When View the MathML source, Young’s integration theory is no longer applicable. However, rough path theory is useful in this case. The main purpose of this paper is to establish a rough path theory for the integration with respect to the local times of symmetric α-stable processes for View the MathML source.
Description: This paper is closed access until 20th March 2018.
2017-01-01T00:00:00Z
Solubilization of phenols by multimolecular aggregates formed by low molecular weight hyperbranched polyglycidol
Olea, Andres F.
Acevedo, Betsabe
Ossandon, Luis
Worrall, David R.
https://dspace.lboro.ac.uk/2134/24523
2017-03-24T10:48:39Z
2017-01-01T00:00:00Z
Title: Solubilization of phenols by multimolecular aggregates formed by low molecular weight hyperbranched polyglycidol
Authors: Olea, Andres F.; Acevedo, Betsabe; Ossandon, Luis; Worrall, David R.
Abstract: Hyperbranched polymers have been proposed as potential carriers or host compartments for controlled drug delivery. In this work the solubilization of alkylphenols into aggregates formed by hyperbranched polyglycidol HPG and its ester derivative has been studied. HPG17 was synthesized by ring-opening polymerization of glycidol, and then the ester HPG4-RBr13 has been obtained by reaction of hPG17 with 2-bromo isobutyryl bromide. The critical aggregate concentration CAC and micropolarity of aggregates were determined by using pyrene as fluorescence probe. CAC values obtained are 2.5mM and 0.25mM, for HPG17 and HPG4-RBr13, respectively. Our results indicate that the hydrophobic effect is larger for HPG4-RBr13, and that their aggregates are more hydrophobic, than for HPG17. In addition, their sizes and sizes distribution were determined by DLS.The partition of phenols between the micellar and aqueous phase was studied by using the pseudo-phase model, and the results show that the partition coefficients increases with increasing length of the side alkyl chain, and are larger for HPG4-RBr13 micelles than for HPG17 micelles.
Description: This paper is closed access until 16th February 2018.
2017-01-01T00:00:00Z