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Abstract

János Kornai was an early and influential critic of rational choice theory, who opposed its application to interdisciplinary questions. In this paper, we attempt to show that certain contemporary uses of rational choice theory are perfectly compatible with Kornai's critique of general equilibrium theory, as well as his broader vision of economics as a mode of understanding. To do so, we leverage the insights of several “ordinary language” philosophers to demonstrate that the utility of rational choice theory derives from its grammatical properties rather than the truth values of its axioms.

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Abstract  

Barium, lanthanum and cerium were determined by excitation using a 100 mCi241Am radioisotope source with the utilization of the K peaks.

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Different types of forest use significantly changed the structure and species composition of European temperate forests. Herbaceous species and seedlings are important parts of the forest ecosystem, thus it is necessary to understand the effects of stand characteristics on the species composition of the understory. In our study we assessed the main factors that affect the species composition of herb and tree seedling assemblages in Quercus petraea and Q. cerris dominated stands (age 50–150 years) in the Bükk Mountains, Hungary. The relationship between the studied assemblages and explanatory variables (tree species composition, stand structure, canopy closure and topography) were explored by Redundancy Analysis (RDA). The occurrence of herbaceous species was affected by canopy closure, stand structure (mean DBH and DBHcv of trees), topography and the density and diversity of shrub layers. Oak forest species were associated with more open stands with sparsely distributed large trees, while mesic forest species were positively associated with heterogeneous stand structure, low shrub density, and western exposure. Seedlings of trees and shrubs showed a dispersal limited phenomenon. The composition of seedlings was significantly influenced by the mean DBH of trees, the structural heterogeneity of the overstory, the tree species diversity and the density of shrub layers. However the seedlings of both dominant oak species required the same stand structure, sessile oak was able to regenerate almost exclusively in those stands where it was dominant in the overstory, which is significant for the management of the species. Generally, forest management affects species composition and structure of the overstory, accordingly it had direct and indirect effects on the understory community as well.

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Extending Blaschke and Lebesgue’s classical result in the Euclidean plane, it has been recently proved in spherical and the hyperbolic cases, as well, that Reuleaux triangles have the minimal area among convex domains of constant width D. We prove an essentially optimal stability version of this statement in each of the three types of surfaces of constant curvature. In addition, we summarize the fundamental properties of convex bodies of constant width in spaces of constant curvature, and provide a characterization in the hyperbolic case in terms of horospheres.

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Orvosi Hetilap
Authors:
Domonkos Pap
,
Ádám Vannay
, and
Attila Szabó J.

Absztrakt:

A vese filtrációs alapegységei a glomerulusok, melyek passzív hemodinamikai feladatukon túl komplex szabályozási mechanizmusokban is részt vesznek. Ezek közül fontosak az immunmediált folyamatok, amelyek a glomerularis homeostasis élettani biztosításán túl lokális szövetkárosító mechanizmusokat is elindíthatnak. Az immunológiai eredetű krónikus glomerularis betegségek gyakori okai a végstádiumú vesebetegség kialakulásának. Az immunrendszer kétélű kardként részt vesz a vese fiziológiás állapotának fenntartásában, de emellett meghatározó szerepe van a glomerularis károsodások kiváltásában. A nem megfelelően szabályozott, túlzott mértékű immunválasz felelős a glomerulonephritisek jelentős részéért, mely folyamat során károsodhat a glomerulusokat alkotó valamennyi strukturális és sejtes elem, beleértve a glomerularis bazálmembránt, a mesangialis és kapilláris-endothelsejteket, a podocytákat, valamint a parietalis epithelsejtréteget. Közleményünkben az egyes glomerularis komponenseknek, valamint a természetes és adaptív immunrendszernek a glomeruluskárosodásban betöltött szerepét foglaljuk össze. Orv Hetil. 2020; 161(24): 993–1001.

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Dry oak forests have one of the richest understory vegetation in Europe, but the environmental drivers of this community have been scarcely revealed. In this study, we assessed whether the amount of light, soil pH or stand heterogeneity affect primarily the species composition of this community. We investigaed 332 sampling plots in 40-165 year old managed and abandoned Quercus cerris and Q. petraea dominated forests in North Hungary. Presence-absence data of herbaceous species and seedlings of woody species were recorded in 28 subplots within each sampling plot. Stand structure, canopy openness and soil pH were also measured in each plot. The relationships between stand characteristics and the species assemblage were explored by redundancy analysis, while the individual responses of species and species groups were studied by generalized linear mixed models. Multivariate methods and individual species response analyses provided similar results, the amount of light and soil pH were equally important variables (both of them explained 2.8% of species variance), while stand heterogeneity had a bit lower, albeit still significant role in determining understory species composition (1.9% of species variance explained). Seedlings of woody species preferred shaded (half-shaded) conditions, while many herbaceous species were positively related to light. The effect of the three explanatory variables was hard to separate, since they influenced each other as well. Sessile oak seedlings and herbs typical of dry forests, forest edges, grasslands and acidic soil habitats preferred light rich habitats with homogeneous stand structure and low soil pH. Mesic forest herbs and seedlings of other woody species were related to relatively high soil pH, heterogeneous stand structure and closed canopy. These two understory types were clearly separated regarding composition. This study emphasizes the importance of heterogenous light conditions and mosaic, diverse forest structure (presence of homogeneous and heterogeneous forest patches) during forest management for the maintenance of understory biodiversity.

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