Development, Testing and Application of ACRE: An Agro-Economic Production Model on Regional Level

ACRE is an Agro-eConomic model for agricultural pRoduction on rEgional level. Based on an extension of Positive Mathematical Programming (PMP) this model was developed as a decision tool for politics with respect to questions of global change scenarios. The validity of the theoretical approach as well as the algorithms has been tested by calculations with empirical data. Currently, ACRE is applied in large interdisciplinary projects. This paper introduces the development of ACRE, from the theoretical framework to testing its validity and current application.mathematical programming, variant-activity, regional model, agricultural production model, interdisciplinary projects, Agribusiness, C61, Q15, E23, Q21,

Constraining the timing of deglaciation of the High Alps and rates of subglacial erosion with cosmogenic nuclides

THESIS ABSTRACTresearc

The influence of climate change, technological progress and political change on agricultural land use: calculated scenarios for the Upper Danube catchment area

Both climate and agricultural policy changes are commonly seen as important drivers for agricultural production. In this study, scenarios of climate and political change were calculated for the Upper Danube catchment area using the regional optimization model ACRE. Two political scenarios were calculated for the year 2020. One scenario assumes the continuation of the Common Agricultural Policy reform 2003 the other assumes a strong shift away from payments of the first pillar to payments of the second pillar of the CAP. Both scenarios were combined with four different scenarios of climate change and technological progress derived from ICCP SRES assumptions and the ACCELERATES project. The results of the scenario calculations were analysed with respect to their implications for the whole catchment area as well as for selected districts. Climate change and technological progress both cause small changes in agricultural land use: fodder crop area tends to be converted to cash crop area, and intensive grasslands tend to be converted into extensive grasslands. Climate change and technological progress increase crop productivity, and consequently, total gross margin increases. The impact of climate change might get stronger toward the end of the century which is beyond the scope of the investigations presented here. The impact of climate change might thus switch from bringing net benefits in the short to medium term to bringing net losses for the area investigated in the long run.global change, regional model, climate change, agricultural policy scenarios, agricultural land use, Agricultural and Food Policy, Environmental Economics and Policy, Land Economics/Use,

DIE EU-ÜBERGANGSREGELUNG ZUM HERKUNFTSSCHUTZ BEI AGRARPRODUKTEN UND LEBENSMITTELN AUS DEM BLICKWINKEL DER TRANSAKTIONS- UND DER INFORMATIONSÖKONOMIE

Seit mittlerweile 15 Jahren besteht mit der Verordnung (EWG) Nr. 2081/92 ein europaweites Schutzsystem für geografische Angaben bei Agrarprodukten und Lebensmitteln. Der Beitrag analysiert auf Grundlage Informationsökonomie und der Transaktionskostenansatzes diese Regelung. Die Analyse zeigt, dass trotz der Neuformulierung der Verordnung im Jahr 2006 weiterhin auf Seiten der Verbraucher die Gefahr der Irreführung besteht und die Regelung der deutschen Ernährungswirtschaft hohe Transaktionskosten verursacht. Ursächlich dafür verantwortlich ist der Kerngedanke der Verordnung, Namen solcher Produkte gegen missbräuchliche Verwendung im Wettbewerb zu schützen, die vom Wesen her als Original aufgrund eigener Geschichte, eigener Rezeptur bzw. besonderer Qualität anzusehen sind. Handlungsbedarf besteht daher sowohl für die durchführende Institution als auch für den Gesetzgeber.Geschützte Herkunftsangaben, Transaktionskosten, Informationsökonomie, Marketing,

Patch-Differentiation of Vegetation and Nutrient Cycling in an Extensive Pasture System

In extensive grazing systems, ‘patch-grazing’ may lead to the development of a mosaic structure consisting of short, frequently defoliated, and tall, infrequently defoliated patches. If spatial patterns of sward structure are stable over time, this may result in a long-term differentiation of botanical composition and matter fluxes between patch types within a pasture. Patch dynamics, botanical composition and topsoil nutrient concentrations of different patch types were investigated in a long-term grazing experiment in the Solling hills, Germany, where differentiated grazing intensities have been applied for 10 years. Continuously stocked beef cattle grazed to target sward heights of 6 or12 cm in a put-and-take system in replicated 1-ha paddocks. Time series of point-specific sward height measurements showed that patches were relatively stable within- and between-seasons. Botanical composition as well as soil phosphorus and potassium concentrations differed between short and tall patches. While grazing intensity influenced the frequency of short and tall patches within a pasture, differences between patch types were larger than those within the same patch type between different grazing intensities. The results highlight the importance of studying biodiversity as well as nutrient dynamics of extensive pastures in a patch-specific way. Through the development of pasture areas with different functionality, extensive grazing systems have the potential to maintain biodiversity while sustaining agricultural production

Indigenous Development: Poverty, Democracy and Sustainability

The contributions included in this volume reflect both the challenges and opportunities of an incipient process of reflection and dialogue between indigenous peoples, governments and development agencies on a subject of vital importance for the approximately 40 million indigenous people of the hemisphere. In addition to the critical issues of poverty reduction, self-development, indigenous rights and secured access to land and natural resources, a common thread throughout this volume is the close interrelationship between sound and sustainable socioeconomic development and the preservation and strengthening of cultural identity. This volume contains the English translation of a selection of essays and presentations made during the International Seminar on Indigenous Development: Poverty, Democracy and Sustainability, organized on the occasion of the First General Assembly of the Fund for the Development of the Indigenous Peoples of Latin America and the Caribbean (Santa Cruz de la Sierra, Bolivia, May 22 and 23, 1995).Democracy, Afro Descendents & Indigenous Peoples, Culture & Arts, Poverty, indigenous peoples, poverty, democracy, sustainability, culture and arts

Electronic properties of graphene encapsulated with different two-dimensional atomic crystals.

Hexagonal boron nitride is the only substrate that has so far allowed graphene devices exhibiting micrometer-scale ballistic transport. Can other atomically flat crystals be used as substrates for making quality graphene heterostructures? Here we report on our search for alternative substrates. The devices fabricated by encapsulating graphene with molybdenum or tungsten disulfides and hBN are found to exhibit consistently high carrier mobilities of about 60 000 cm(2) V(-1) s(-1). In contrast, encapsulation with atomically flat layered oxides such as mica, bismuth strontium calcium copper oxide, and vanadium pentoxide results in exceptionally low quality of graphene devices with mobilities of ∼1000 cm(2) V(-1) s(-1). We attribute the difference mainly to self-cleansing that takes place at interfaces between graphene, hBN, and transition metal dichalcogenides. Surface contamination assembles into large pockets allowing the rest of the interface to become atomically clean. The cleansing process does not occur for graphene on atomically flat oxide substrates.This work was supported by the European Research Council, Graphene Flagship, Engineering and Physical Sciences Research Council (UK), the Royal Society, US Office of Naval Research, US Air Force Office of Scientific Research, US Army Research Office

Electronic Properties of Graphene Encapsulated with Different Two-Dimensional Atomic Crystals

Hexagonal boron nitride is the only substrate that has so far allowed graphene devices exhibiting micron-scale ballistic transport. Can other atomically flat crystals be used as substrates for making quality graphene heterostructures? Here we report on our search for alternative substrates. The devices fabricated by encapsulating graphene with molybdenum or tungsten disulphides and hBN are found to exhibit consistently high carrier mobilities of about 60,000 cm$^{2}$V$^{-1}$s$^{-1}$. In contrast, encapsulation with atomically flat layered oxides such as mica, bismuth strontium calcium copper oxide and vanadium pentoxide results in exceptionally low quality of graphene devices with mobilities of ~ 1,000 cm$^{2}$ V$^{-1}$s$^{-1}$. We attribute the difference mainly to self-cleansing that takes place at interfaces between graphene, hBN and transition metal dichalcogenides. Surface contamination assembles into large pockets allowing the rest of the interface to become atomically clean. The cleansing process does not occur for graphene on atomically flat oxide substrates.Comment: 19 pages, 11 figures, 1 table including Supporting Informatio

Exhumed hydrocarbon-seep authigenic carbonates from Zakynthos island (Greece): Concretions not archaeological remains

In Zakynthos Island (Greece), authigenic cementation of marine sediment has formed pipelike, disc and doughnut-shaped concretions. The concretions are mostly composed of authigenic ferroan dolomite accompanied by pyrite. Samples with >80% dolomite, have stable isotope compositions in two groups. The more indurated concretions have δ 18O around +4‰ and δ 13C values between -8 and -29‰ indicating dolomite forming from anaerobic oxidation of thermogenic methane (hydrocarbon seep), in the sulphate-methane transition zone. The outer surfaces of some concretions, and the less-cemented concretions, typically have slightly heavier isotopic compositions and may indicate that concretion growth progressed from the outer margin in the ambient microbially-modified marine pore fluids, inward toward the central conduit where the isotopic compositions were more heavily influenced by the seep fluid. Sr isotope data suggest the concretions are fossil features, possibly of Pliocene age and represent an exhumed hydrocarbon seep plumbing system. Exposure on the modern seabed in the shallow subtidal zone has caused confusion, as concretion morphology resembles archaeological stonework of the Hellenic period