Women live longer than men because they have two X chromosomes in their
genomes and any defective gene in one X chromosome can be complemented by
the wild gene located in the second copy. Men have one copy of X
chromosome and almost empty Y chromosome which determines the male sex.
Thus, the problem is caused by the shrinking Y chromosome. Our simulations
have shown that Y chromosome shrinks because of the promiscuity of women.
We have used the Penna ageing model to analyze how the difference in
evolution of sex chromosomes depends on the strategy of reproduction. In
panmictic populations, when women (XX) can freely choose the men (XY) as a
partner for reproduction from the whole population, the Y chromosome
accumulates defects and eventually the only information it brings is a
male sex determination. As a result of shrinking Y chromosome the males
become hemizygous in respect to the X chromosome content and are
characterized by higher mortality, observed in the human populations. If
it is assumed in the model that the presence of the male is indispensable
at least during the pregnancy of his female partner and he cannot be
seduced by another female at least during the one reproduction cycle - the
Y chromosome preserves its content, does not shrink and the lifespan of
females and males is the same. Thus, Y chromosome shrinks not because of
existing in one copy, without the possibility of recombination, but
because it stays under weaker selection pressure; in panmictic populations
without the necessity of being faithful, a considerable fraction of males
is dispensable, they can be altruistic going to Iraq to fight for peace.
2. Prof. Janusz Holyst
Dr Agata Fronczak
Dr Piotr Fronczak
Faculty of Physics, Warsaw University of Technology
We will present the linear theory of nonequilibrium thermodynamics applied to
random networks with arbitrary degree distribution. Using the well-known
methods of nonequilibrium thermodynamics we identify thermodynamic forces
and their conjugated flows induced in networks as a result of single node degree
perturbation. The forces and the flows can be understood as a response of the
system to events, such as random removal of nodes or intentional attacks on
them. Finally, we show that cross effects such as thermodiffusion, or
thermoelectric phenomena, in which one force may not only give rise to its
own conjugated flow, but to many other flows, can be observed also in complex
networks.
3. Prof. Krzysztof Kulakowski
Faculty of Physics and Applied Computer Science,
AGH University of Science and Technology
A line is drawn from the Ising interaction through the Sznajd dynamics to the game theory and to the norm game, which is an example of adaptive thinking. In this game, the strategies are: to obey the norm or not and to punish those who break it or not. The punishment, the temptation, the punishment cost and the relaxation of vengeance are modeled by four parameters. New master equations are proposed. Their analysis reveals different phases and possible bifurcations in the system dynamics. Some conclusions are supported by the Monte Carlo simulations on a directed random network.
4. Prof. Ryszard Kutner
Department of Physics, University of Warsaw
Title: Multifractal Continuous-Time Random Walk on financial markets
We developed the Multifractal Continuous-Time Random Walk (MF-CTRW) formalism for the description of the multifractal structure of random intertransaction time-intervals, which we found when futures on USD/DEM foreign exchange rate (on FX market), the futures on DAX as well as WIG were intensively traded (archival data). In the frame of the MF-CTRW formalism we used the basic distribution, i.e. the Pausing-Time Distribution (PTD), in the form of the convolution (superstatistics), where its integral kernel is given by the stretched exponential function instead of the exponential one applied by the earlier versions of the Continuous-Time Random Walk (CTRW) formalism. Some more rafined but heuristic analytical predictions were also considered, which we call Heuristic Multifractal Continuous-Time Random Walk (HMF-CTRW) model. As a result we found that: (i) the spectrum of singularities is the left-sided and unlimited (i.e., we have to deal with spectrum of singularities which is unlimited for its right side) and (ii) the third-order phase transition was found which can be roughly interpreted as transition between the phase where high frequency trading is most visible to the phase defined by the low frequency trading. This is the first time when both considered properties were simultaneously observed on financial market.
5. Prof. Danuta Makowiec
Institute of Theoretical Physics and Astrophysics,
Gdansk Univeristy
Title: A network of cellular automata as the cardiac pacemaker
Cellular automata are discrete spatially extended systems which despite
their simplicity can reproduce significant features of reality. The
Greenberg-Hastings cellular automata are usually used to model the
excitable medium. We will demonstrate that a specially organized network (local rewiring
of diluted square lattice with preferences to highly connected nodes )
of cellular automata with cyclic inner dynamics (FIRING --> REFRACTORY
--> ACTIVITY --> FIRING ...., where time steps spent in each state,
timings, are stochastic) is a reliable approximation of the cardiac
pacemaker. The system self-organizes to the rhythmic evolution with the period
driven by timings. There is emerged a small group of neighboring
automata --- leading center, which initiates the system activity.
Moreover, the dominant evolution is accompanied with other rhythms,
characterized by longer periods, presence of which can be seen as
sources of possible arrhythmia.
6. Dr Maria S. Magdon-Maksymowicz
Department of Mathematical Statistics,
AR Agricultural University
Prof. Andrzej Z. Maksymowicz
Faculty of Physics and Applied Computer Science,
AGH University of Science and Technology
Title: Population structure and dynamics for Penna model with age-modified mutation rate.
The population size n and its structure is governed by competition between birth and death rates. In a primitive approach, a constant death rate p=h, if smaller than birth rate b, leads to unlimited population growth. (For h>b the population is extinct.) To avoid infinite growth, Verhulst introduced concept of limited environmental capacity N so that the death rate p is controlled by population size n, p=n/N. This is the logistic model; Penna model may be seen as another mechanism of possible death due to bad mutations introduced to offsprings with mutation rate m. The net death rate p is therefore the sum of contributions of different origins: p = h + n/N + g, where g(m) stands for genetic death rate caused by bad mutations. In this paper we replace model parameter m by parent's age a modified value m(a) to account for the tendency of a bigger risk of bad mutations experienced by babies from older parents. Linear dependence m(a) = m(0) + p*a is proposed and so we have 2 model parameters, m(0) and p,
instead of a single value m. The slope p of m(a) dependence is scanned and m(0) is matched so that we recover the same population n as the one for the reference standard case p=0. The results of p>0 are discussed in terms of changes in population structure n(a,L) of age a and genome length L, then death ratio p and its relative components: h, n/N and g, are also different. (Genome length L is the deadly bit position which makes genetic death occur at a=L, and population individuals have L's with some upper limit Lm.) Main conclusions are: with increasing p, 1)maximum Lm increases, 2)mortality q(a) = 1 - n(a+1)/n(a) is bigger for items in the middle age, yet q(a) is smaller for the oldest one when a approaches Lm and 3)more
distinct deviation from the Gompertz exponential law of q(a) is reported.
7. Dr Krzysztof Malarz
Faculty of Physics and Applied Computer Science,
AGH University of Science and Technology
Title: Search for bottleneck effects in Penna ageing and Schulze language model
In reversible models like the Ising paramagnet above the Curie temperature, the equilibrium distribution is independent of the initial distribution. This is not always the case in systems with memory, for example if a small fraction of elements always remains at the initial states. In biology, at a ``bottlenec'' (see e.g. [1]) most of the population dies out e.g. due to an environmental catastrophe, and then the population grows back to about its old size. Immediately after this bottleneck, the distribution of genes then is an equilibrium distribution, which in general differs from both a random distribution and the case where all genomes are identical. Then, if the system has long-time memory, the final genetic distribution long after the bottleneck can be different from the one immediately before the bottleneck.
Such bottleneck effects in the Penna model [2] for biological ageing
and the Schulze model [3] for human languages is lacking [4].
[1] J. S. S'a Martins and S. Moss de Oliveira,
Int. J. Mod. Phys. C 9, 421 (1998); J. P. Radomski and
S. Moss de Oliveira, Int. J. Mod. Phys. C 11, 1297 (2000).
[2] T. J. P. Penna, J. Stat. Phys. 78, 1629 (1995).
[3] C. Schulze and D. Stauffer, Computing
in Science and Engineering 8, 86 (2006)
[4] K. Malarz and D. Stauffer, arXiv:q-bio/0609051
8. Prof. Andrzej Nowak
Department of Psychology, University of Warsaw
Title: Social factors in economic transition, the case of Poland
9. Prof. Dietrich Stauffer
Institute of Theoretical Physics,
Cologne University
Title: Computer simulations of demography of ageing
Life expectancy increases, and birthrate has fallen down, in most of the
world. Who then pays for the wodka during my retirement? Increasing
retirement age and immigration alleviate problems in Germany. Countries
like Poland with a more recent sharp drop in birth rates still have
some time to prepare for the problems of an ageing society. Ater the
year 2030 they can become increasingly serious.
10. Prof. Lukasz A. Turski
Center for Theoretical Physics of the Polish Academy of Sciences
Title: Gauge Field Theory of Waves in Solids with Topological Defects
Forty years ago I was working on the continuous theory of dislocations, and in that connection I I was invited to a lab i Germany where Dieter was working for a while. I never went there, for I was denier passport. When I finally met Dieter, years later, we were already working on very different topics. My talk on this meeting will be devoted to my recent work on the theory of dislocations (now called topological defects) which can be traced back to the loose ends left in the pre-historic theory of those defects and which shows how modern physics tools (gauge field theory etc) can be used to understand much better even the most classical issues like propagation of waves in solids.