THE ROLE OF WATER IN LANDSCAPE ECOLOGY AND IN CROP PRODUCTION

Water is an element of integration and interaction. Through its continuing cycles and re- newal water maintains a finely tuned harmony between local diversity and macroscale co- herence within natural evolution. Even a tentative review of the role of water in landscape ecology and in crop production clearly reveals that the holistic and dynamic character of nature's structure and functioning sharply contrasts and conflicts with the fragmented and static nature of the market induced industrial strategies and technologies. The causes and consequences of these gradually intensifying and accelerating conflicts are first outlined in a conceptual and historical framework then illustrated by indicative examples taken from recent studies on water related planning and policies in Hungary. A move towards reducing and preventing such conflicts seems to require, among many other things, the compilation of broadly conceived analytical studies on major water related prerequisites and consequences of various future scenarios. This can lead to a coherent set of matrices between the valued components of the region's water resources and the human activities affecting water balance and water quality. Problem-based and process-oriented internal and external integration of hydrological sciences - towards which significant contribu- tions have been already made during the last few years - seems to be the key element in the elaboration of such comprehensive informational basis on the role of water in nature and in society

Global Issues through ELT

Készült az ELTE Felsőoktatási Struktúraátalakítási Alapból támogatott programja keretében

Új típusú elágazott topológiájú polimerek = New types of polymers with branched topology

Szisztematikus alapkutatásokat folytattunk hiperelágazásos polimerek képződési körülményei és a képződött polimerek tulajdonságai közötti összefüggések felderítése érdekében a következő irányokban: 1. Hiperelágazásos polisztirol önojtásos módszerrel történő előállítása karbokationos polimerizációval és a reakciókörülmények hatása erre a folyamatra. 2. Csillag polimer előállítása két lépcsőben, egy reaktorban. 3. Elágazásos kopolimerek szintézise kváziélő atomátadásos gyökös polimerizá-cióval (ATRP) bifunkciós komonomer jelenlétében. 4. Hiperelágazásos és csillag polimerek előállítása AB2 inimerek felhasználásával. Univerzális gélpermeációs kromatográfiás (GPC) és fényszóródási detektálással, valamint 1H-NMR spektroszkópiával analizálva a kapott polimereket, megállapítottuk a reakcióparaméterek szerepét az önojtással képződő polisztirol szerkezeti paramétereire, amely lehetőséget biztosít az elágazások számának szabályozására. Izobutilén és sztirol szekvenciális adagolásával, majd a polisztirol szegmensek önojtásával új típusú, hiperelágazásos maggal rendelkező csillag poliizobutilént állítottunk elő. Kidolgoztuk mono- és bifunkciós kononomerek kváziélő atomátadásos gyökös kopolimerizációjával (ATRP) jól oldható hiperelágazásos polimerek előállítását. Új AB2 inimer karbokationos polimerizációjával és azt követő monomer adagolással új eljárást dolgoztunk ki csillag poliizobutilén előállítására. | Systematic fundamental research has been carried out by us on revealing the relationships between reaction conditions of the syntheses and the properties of the resulting hyperbranched polymers in the following directions: 1. Synthesis of hyperbranched polystyrene by self-grafting via carbocationic polymerization and the effect of reaction conditions on this process. 2. Preparation of star polymers by a two step one-pot reaction. 3. Synthesis of hyperbranched polymers by quasiliving atom transfer copolymerization (ATRP) with bifunctional monomers. 4. Preparation of hyperbranched and star polymers from AB2 inimers. Analysis of the resulting polymers obtained by self-grafting with gelpermeation chromatograpy (GPC) and 1H NMR revealed the role of reaction parameters on the structure of the branched macromolecules. New types of star polyisobutylene with hyperbranched core were obtained by the sequential addition of isobutylene and styrene followed by self-grafting of the polystyrene segments. A new method was developed by us via the atom transfer copolymerization of mono- and bifunctional monomers. A new process was successfully exploited for the synthesis of start polyisobutylene via carbocationic polymerization of a new AB2 inimer and subsequent monomer addition

A macroeconomics-inspired interpretation of the terrestrial water cycle

This article develops an approach that applies macroeconomic concepts to the interpretation of complex, water related natural processes. By translating and reinterpreting these processes into a language that is more accessible to a broader audience otherwise unaccustomed to its terms will likely help sharpen our understanding of the terrestrial water cycle. For economists, we describe climate-forming natural processes in a manner consistent with the fundamentals of the mainstream approach. For noneconomists, parallels from economically determined, relatively short-term observations can be applied conceptually to identify dynamics which occur over much longer and therefore more elusive natural occurrences, in particular considering the role of forests and how persistent land conversion over a millennium has shaped the earth's surface and impacted climate stability. The set of “supporting ecosystem services” highlighted in the Millennium Ecosystem Assessment (MEA) coincides with the ground phase of the terrestrial water cycle, taking the concept beyond the ecosystem service perspective and identifying it as a planetary service. Ecosystem and planetary services differ in the same way that microeconomic and macroeconomic perspectives do. The water cycle intensity of a geographical area may well be related to a rainfall multiplier that measures the ability of continental ecosystems to increase the amount of water moving across terrestrial surfaces and descending as rainfall through transpiration and deposition, and re-transpiration and re-deposition of the water content in the air that originally arrives from the oceans. Building upon the MEA's association of human wellbeing with ecosystem features, the rainfall multiplier serves as a physical indicator and measure of the natural basis of wellbeing creation