Effect of sampling effort and sampling frequency on the composition of the planktonic crustacean assemblage: a case study of the river Danube

Although numerous studies have focused on the seasonal dynamics of riverine zooplankton, little is known about its short-term variation. In order to examine the effects of sampling frequency and sampling effort, microcrustacean samples were collected at daily intervals between 13 June and 21 July of 2007 in a parapotamal side arm of the river Danube, Hungary. Samples were also taken at biweekly intervals from November 2006 to May 2008. After presenting the community dynamics, the effect of sampling effort was evaluated with two different methods; the minimal sample size was also estimated. We introduced a single index (potential dynamic information loss; to determine the potential loss of information when sampling frequency is reduced. The formula was calculated for the total abundance, densities of the dominant taxa, adult/larva ratios of copepods and for two different diversity measures. Results suggest that abundances may experience notable fluctuations even within 1 week, as do diversities and adult/larva ratios.

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.

Arrow-Debreu-modell és a Kornai-kritika harminc év után = The Arrow-Debreu Model and Kornai s critique, thirty years after

Több mint harminc év telt el Kornai János Anti-equilibrium című könyvének megjelenése óta. Ez volt az első mű a nemzetközi irodalomban, amely átfogóan bírálta az általános egyensúlyelméletet, mégpedig Debreu értékelméletén és az Arrow-Debreu modellen keresztül. A kritikára legélesebben Frank H. Hahn reagált, amire Kornai - fenntartva korábbi bírálatainak többségét - a közelmúltban megjelent önéletrajzában tért vissza. E cikkben elmélettörténeti előzményekkel együtt rekonstruáljuk a Kornai-Hahn-vita főbb pontjait, és megvizsgáljuk a kritikák és riposztok érvényességét. Látni fogjuk, hogy a legújabb közgazdasági elméletek nem mindenben igazolták Hahn ellenvetéseit. _______________ More than thirty years have passed since János Kornai s book Anti-Equilibrium appeared. This was the first work in international literature to criticize comprehensively the general theory of equilibrium, moreover through the value theory of Debreu and the Arrow-Debreu Model. The sharpest reaction to the criticism came from Frank H. Hahn, and Kornai returned to this in his recent autobiography. This article reconstructs the main points in the Kornai-Hahn debate, including its antecedents in the history of theory, and examines the validity of the criticisms and ripostes. It will be seen that Hahn s objections have not been endorsed in every respect by the latest economic theories.