498 research outputs found
Commodity and Financial Networks in Regional Economics
The article discusses the relationship between commodity-production and financial network structures in the regional economy as dual conjugate systems. Material flows (raw materials, goods and so on) circulate in the commodity network as shown by Leontiev’s input-output balance model. Nonmaterial flows of property rights, money, and so on circulate in the financial network and reflect the movement of material objects in commodity networks. A network structure comprises closed and open circuits, which have fundamentally different characteristics: locally closed circuits meet local demand by supplying locally produced goods, thus ensuring self-reproduction of the local economy; open (or transit) circuits provide export-import flows. The article describes the mechanism of ‘internal’ money generation in closed circuits of commodity-production networks. The results of the theoretical study are illustrated by the calculations of closed and open circuit flows in the municipal economy model. Mutual settlements between the population and manufacturing enterprises are given in matrix form. It was found that the volume of the turnover in closed circuits of the municipal economic network model is about 28.5 % of the total turnover and can be provided by ‘internal’ non-inflationary money. The remaining 71.5 % of the total turnover correspond to the flows in the network’s open circuits providing export and import. The conclusion is made that in the innovation-driven economy, main attention should be given to the projects oriented towards domestic consumption rather than export supplies. The economy is based on internal production cycles in closed circuits. Thus, it is necessary to find the chains in the inter-industrial and inter-production relations which could become the basis of the production cycle. Money investments will complete such commodity chains and ‘launch’ the production cycle.The work has been prepared with the supprot of the Ural Federal University within the UrFU Program for the winners of the competition “Young Scientists of UrFU” No. 2.1.1.1-14/43
Phase-plane analysis of driven multi-lane exclusion models
We show how a fixed point based boundary-layer analysis technique can be used
to obtain the steady-state particle density profiles of driven exclusion
processes on two-lane systems with open boundaries. We have considered two
distinct two-lane systems. In the first, particles hop on the lanes in one
direction obeying exclusion principle and there is no exchange of particles
between the lanes. The hopping on one lane is affected by the particle
occupancies on the other, which thereby introduces an indirect interaction
among the lanes. Through a phase plane analysis of the boundary layer equation,
we show why the bulk density undergoes a sharp change as the interaction
between the lanes is increased. The second system involves one lane with driven
exclusion process and the other with biased diffusion of particles. In contrast
to the previous model, here there is a direct interaction between the lanes due
to particle exchange between them. In this model, we have looked at two
possible scenarios with constant (flat) and non-constant bulk profiles. The
fixed point based boundary layer method provides a new perspective on several
aspects including those related to maximal/minimal current phases,
possibilities of shocks under very restricted boundary conditions for the flat
profile but over a wide range of boundary conditions for the non-constant
profile.Comment: 13 pages, 17 figure
Analysis of segmental residual growth after progressive bone lengthening in congenital lower limb deformity
SummaryIntroductionThe issue of prognosis in limb length discrepancy in children affected by congenital abnormality remains a subject of concern. Therapeutic strategy must take length prediction into account, to adapt equalization techniques and the timing of treatment. Initial prognosis, however, may need revising after completion of one or several surgical interventions on the pathologic limb. The aim of this study was to determine the different types of growth response that a bone segment can present after progressive lengthening in case of congenital limb length discrepancy.Materials and methodsA series of 114 bone lengthenings with external fixator, performed in 36 girls and 50 boys with congenital lower limb length discrepancy, was retrospectively analyzed. Bone segment growth rates were measured before lengthening, during the first year after frame removal and finally over long-term follow-up, calculating the ratios of radiological bone length to the number of months between two measurements. Mean follow-up was 4.54±0.2 years.ResultsChanges in short- and long-term growth rate distinguished five patterns of bone behavior after lengthening, ranging from growth acceleration to total inhibition.DiscussionThese five residual growth patterns depended on certain factors causing acceleration or, on the contrary, slowing down of growth: age at the lengthening operation, percentage lengthening, and minimal period between two lengthenings. These criteria help optimize conditions for resumed growth after progressive segmental lengthening, avoiding conditions liable to induce slowing down or inhibition, and providing a planning aid in multi-step lengthening programs.Level of evidenceLevel IV. Retrospective study
Why spontaneous symmetry breaking disappears in a bridge system with PDE-friendly boundaries
We consider a driven diffusive system with two types of particles, A and B,
coupled at the ends to reservoirs with fixed particle densities. To define
stochastic dynamics that correspond to boundary reservoirs we introduce
projection measures. The stationary state is shown to be approached dynamically
through an infinite reflection of shocks from the boundaries. We argue that
spontaneous symmetry breaking observed in similar systems is due to placing
effective impurities at the boundaries and therefore does not occur in our
system. Monte-Carlo simulations confirm our results.Comment: 24 pages, 7 figure
On the Fibonacci universality classes in nonlinear fluctuating hydrodynamics
We present a lattice gas model that without fine tuning of parameters is
expected to exhibit the so far elusive modified Kardar-Parisi-Zhang (KPZ)
universality class. To this end, we review briefly how non-linear fluctuating
hydrodynamics in one dimension predicts that all dynamical universality classes
in its range of applicability belong to an infinite discrete family which we
call Fibonacci family since their dynamical exponents are the Kepler ratios
of neighbouring Fibonacci numbers , including
diffusion (), KPZ (), and the limiting ratio which is the
golden mean . Then we revisit the case of two
conservation laws to which the modified KPZ model belongs. We also derive
criteria on the macroscopic currents to lead to other non-KPZ universality
classes.Comment: 17 page
Far-from-equilibrium transport with constrained resources
The totally asymmetric simple exclusion process (TASEP) is a well studied
example of far-from-equilibrium dynamics. Here, we consider a TASEP with open
boundaries but impose a global constraint on the total number of particles. In
other words, the boundary reservoirs and the system must share a finite supply
of particles. Using simulations and analytic arguments, we obtain the average
particle density and current of the system, as a function of the boundary rates
and the total number of particles. Our findings are relevant to biological
transport problems if the availability of molecular motors becomes a
rate-limiting factor.Comment: 14 pages, 7 figures, uses iopart12.clo and iopart.cl
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