The Closed Loop Model by Regional Economics or How Big is the Ants’ Footprint?

The economy is communication between Man and Nature. It is an interaction-network between our outside and inside Nature, that is, the external Nature surrounding us and the internal nature expressing our human essence. Money is an institution of the society, an infrastructure that ensures division of labour, enables the flow of information and material between the participants. The concept of regional material and financial circular flow will be more important with the oncoming peak-oil and post-carbon era. We should describe in time the outlines of closed or semi-closed loops economy. The fundamentals of Input-Output will flourish once again; it could help us formulate the link between the efficiency and resiliency of a regional complex system.

The effect of climate change on the population of sycamore lace bug (Corythuca ciliata, Say) based on a simulation model with phenological response

Climate change affects on insect populations in many ways: it can cause a shift in geographical spread, abundance, or diversity, it can change the location, the timing and the magnitude of outbreaks of pests and it can define the phenological or even the genetic properties of the species. Long-time investigations of special insect populations, simulation models and scenario studies give us very important information about the response of the insects far away and near to our century. Getting to know the potential responses of insect populations to climate change makes us possible to evaluate the adaptation of pest management alternatives as well as to formulate our future management policy. In this paper we apply two simple models, in order to introduce a complex case study for a Sycamore lace bug population. We test how the model works in case the whether conditions are very different from those in our days. Thus, besides we can understand the processes that happen in present, we can analyze the effects of a possible climate change, as well.

An agro-ecological simulation model system

In this paper five different models, as five modules of a complex agro-ecosystem are investigated. The water and nutrient flow in soil is simulated by the nutrient-in-soil model while the biomass change according to the seasonal weather aspects, the nutrient content of soil and the biotic interactions amongst the other terms of the food web are simulated by the food web population dynamical model that is constructed for a piece of homogeneous field. The food web model is based on the nutrient-in-soil model and on the activity function evaluator model that expresses the effect of temperature. The numbers of individuals in all phenological phases of the different populations are given by the phenology model. The food web model is extended to an inhomogeneous piece of field by the spatial extension model. Finally, as an additional module, an application of the above models for multivariate state-planes, is given. The modules built into the system are closely connected to each other as they utilize each other’s outputs, nevertheless, they work separately, too. Some case studies are analysed and a summarized outlook is given.

Simulation modeling of phytoplankton dynamics in a large eutrophic river, Hungary – Danubian Phytoplankton Growth Model (DPGM)

Ecological models have often been used in order to answer questions that are in the limelight of recent researches such as the possible effects of climate change. The methodology of tactical models is a very useful tool comparison to those complex models requiring relatively large set of input parameters. In this study, a theoretical strategic model (TEGM ) was adapted to the field data on the basis of a 24-year long monitoring database of phytoplankton in the Danube River at the station of G¨od, Hungary (at 1669 river kilometer – hereafter referred to as “rkm”). The Danubian Phytoplankton Growth Model (DPGM) is able to describe the seasonal dynamics of phytoplankton biomass (mg L−1) based on daily temperature, but takes the availability of light into consideration as well. In order to improve fitting, the 24-year long database was split in two parts in accordance with environmental sustainability. The period of 1979–1990 has a higher level of nutrient excess compared with that of the 1991–2002. The authors assume that, in the above-mentioned periods, phytoplankton responded to temperature in two different ways, thus two submodels were developed, DPGM-sA and DPGMsB. Observed and simulated data correlated quite well. Findings suggest that linear temperature rise brings drastic change to phytoplankton only in case of high nutrient load and it is mostly realized through the increase of yearly total biomass.

A vállalatok nemzetköziesedésének dinamikája – egy kutatási modell (Dynamics of firm internationalization – a research model)

A tanulmány a nemzetköziesedés elméleti modelljeinek hiányosságaival szembesülve amellett érvel, hogy ahhoz, hogy megértsük a nemzetköziesedés időben zajló folyamatát, a vállalatok nemzetközi evolúcióját a kontextussal összefüggésben kell vizsgálni. A tanulmány a vállalatok nemzetköziesedésének folyamatát vizsgáló elméleti szakirodalomra építve egy olyan kutatási modellt vázol fel, amely alkalmas lehet a nemzetköziesedés dinamikájának empirikus vizsgálatához. A modell a belépés, diverzitás, ütem és szakasz koncepciók mentén operacionalizált nemzetköziesedés mintázata és a kontextus (környezet, vállalat, menedzsment) közötti kapcsolatot teremti meg. A vázolt kutatási modell empirikus alkalmazásával lehetővé válik a nemzetközivé válás folyamata során kialakuló komplex kapcsolatrendszer feltárása és megértése. ________ Addressing some of the limitations of the theoretical models of firm internationalization this paper argues that in order to understand the process of firm internationalization along time one should observe firms and their contextual environments as complex interacting processes. Drawing on the theoretical models of firm internationalization process this study proposes a research model that may be suitable for the empirical examination of the dynamics of internationalization. The proposed model builds a relationship between the pattern of firm internationalization operationalized via concepts such as entry, diversity, pace, phases and the context (environment, firm, management) of it. By analyzing the interaction between the multi-level processes that shape internationalization, one can explore the reasons behind the dynamic profile of firm internationalization.