8 resultados para family ecological model

em Corvinus Research Archive - The institutional repository for the Corvinus University of Budapest


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Our aim was to approach an important and well-investigable phenomenon – connected to a relatively simple but real field situation – in such a way, that the results of field observations could be directly comparable with the predictions of a simulation model-system which uses a simple mathematical apparatus and to simultaneously gain such a hypothesis-system, which creates the theoretical opportunity for a later experimental series of studies. As a phenomenon of the study, we chose the seasonal coenological changes of aquatic and semiaquatic Heteroptera community. Based on the observed data, we developed such an ecological model-system, which is suitable for generating realistic patterns highly resembling to the observed temporal patterns, and by the help of which predictions can be given to alternative situations of climatic circumstances not experienced before (e.g. climate changes), and furthermore; which can simulate experimental circumstances. The stable coenological state-plane, which was constructed based on the principle of indirect ordination is suitable for unified handling of data series of monitoring and simulation, and also fits for their comparison. On the state-plane, such deviations of empirical and model-generated data can be observed and analysed, which could otherwise remain hidden.

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The Leontief input-output model is widely used to determine the ecological footprint of consumption in a region or a country. It is able to capture spillover environmental effects along the supply change, thus its popularity is increasing in ecology related economic research. These studies are static and the dynamic investigations are neglected. The dynamic Leontief model makes it possible to involve the capital and inventory investment in the footprint calculation that projects future growth of GDP and environmental impacts. We show a new calculation method to determine the effect of capital accumulation on ecological footprint. Keywords: Dynamic Leontief model, Dynamic ecological footprint, Environmental management, Allocation method

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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.

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A tanulmányban országok környezetterhelését és jóllétét vizsgáljuk. A környezetterhelést vizsgáló klasszikus I = PAT azonosság célszerű átrendezésével és továbbgondolásával két térképet szerkesztünk, amelyek egy véges, korlátozott erőforrású világban segítik a stratégiai döntéshozatalt. A térképek adatait a bruttó hazai termék, az ökológiai lábnyom, illetve a szubjektív jóllét mutatói szolgáltatják, ezek az információk a világ országaira ma már széles körben rendelkezésre állnak. Bemutatjuk a gazdasági tevékenység és a szubjektív jóllét kapcsolatát, s az erre épülő 12 stratégiát, majd a szűkös természeti erőforrásokkal számot vető újabb 12 stratégialehetőséget tárgyaljuk. A gazdasági tevékenységet, a környezeti korlátokat és az emberi boldogságot egyszerre szem előtt tartó modell alapján nyilvánvaló a makroszintű következtetés: napjainkban a gazdasági tevékenység, illetve az emberi jóllét dematerializációja szükséges és kívánatos célkitűzés /===/ The study examines countries' ecological footprint and welfare. Rearranging and developing the classic I = PAT equation, the author has devised two maps to assist strategic decision-making in a world of finite, limited resources. The data on the maps – GDP, ecological footprint, and subjective welfare indices – are all widely available all over the world. The relation between economic activity and subjective welfare is presented and twelve strategies built upon them, before discussing twelve further strategies based on scarce natural resources. Using a model that considers economic activity, environmental constraints and human happiness concurrently, it becomes obvious that dematerialization of economic activity and human welfare are a necessary and desirable objective.

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Climate change has a great impact on the build and the work of natural ecosystems. Disappearance of some population or growth of the number in some species can be already caused by little change in temperature. A Theoretical Ecosystem Growth Model was investigated in order to examine the effects of various climate patterns on the ecological equilibrium. The answers of the ecosystems which are given to the climate change could be described by means of global climate modelling and dynamic vegetation models. The examination of the operation of the ecosystems is only possible in huge centres on supercomputers because of the number and the complexity of the calculation. The number of the calculation could be decreased to the level of a PC by considering the temperature and the reproduction during the modelling of a theoretical ecosystem and several important theoretical questions could be answered.

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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.

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A vállalkozási tevékenység a munkahelyteremtés és a gazdasági növekedés egyik döntő tényezője. Ennek a jövőbeli kedvező alakulását a fiatalok mai attitűdjei határozzák meg. Ha be tudjuk azonosítani a legfontosabb tényezőket, amelyek a fiatalok vállalkozásindítási szándékát befolyásolják, el tudjuk dönteni azt is, mely területen lehet és érdemes beavatkozni annak érdekében, hogy minél több új, életképes vállalkozás szülessen. A cikk a GUESSS kutatási projekt magyarországi adatbázisának köszönhetően közel 6000 hallgató válaszait elemezve rendszerezi a felsőoktatásban résztvevők vállalkozásindítási szándékára ható legfontosabb tényezőcsoportokat. Első lépésben Ajzen tervezett magatartás elméletének alkalmazásával vizsgálja a vállalkozásindítási szándék alakítóit, majd további tényezők, így a felsőoktatási intézmények által nyújtott szolgáltatások, a családi háttér és a demográfiai jellemzők bevonásával igyekszik minél pontosabban leírni a szándék alakulását. _____ Entrepreneurial activity is a decisive factor in the dynamics of job creation and economic growth. The future level of this activity highly depends on the attitudes of today’s youth towards this. If the most important factors influencing attitudes are identified and the entrepreneurial intentions towards entrepreneurship are determined, the fields of intervention targeting the creation of as many new and viable enterprises as possible can be defined. This article aims to systematise the most important factor groups that influence the decisions of students studying in higher education in terms of start-up activities and is based on the Hungarian database of the GUESSS research project, containing almost 6000 respondents. Firstly, it tests Ajzen’s Theory of Planned Behavior. Then such factors as supportive services provided by higher education institutions, family background and demographic factors are analysed in order to improve the explanatory power of the model.

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It is crucial to understand the role that labor market positions might play in creating gender differences in work–life balance. One theoretical approach to understanding this relationship is the spillover theory. The spillover theory argues that an individual’s life domains are integrated; meaning that well-being can be transmitted between life domains. Based on data collected in Hungary in 2014, this paper shows that work-to-family spillover does not affect both genders the same way. The effect of work on family life tends to be more negative for women than for men. Two explanations have been formulated in order to understand this gender inequality. According to the findings of the analysis, gender is conditionally independent of spillover if financial status and flexibility of work are also incorporated into the analysis. This means that the relative disadvantage for women in terms of spillover can be attributed to their lower financial status and their relatively low access to flexible jobs. In other words, the gender inequalities in work-to-family spillover are deeply affected by individual labor market positions. The observation of the labor market’s effect on work–life balance is especially important in Hungary since Hungary has one of the least flexible labor arrangements in Europe. A marginal log-linear model, which is a method for categorical multivariate analysis, has been applied in this analysis.