OPTIMAL LAND CONVERSION AND GROWTH WITH UNCERTAIN BIODIVERSITY COSTS

An important characteristic defining the threat of environmental crises is the uncertainty about their consequences for future welfare. Random processes governing ecosystem dynamics and adaptation to anthropogenic change are important sources of prevailing ecological uncertainty and contribute to the problem of how to balance economic development against natural resource conservation. The aim of this study is to examine optimal growth subject to non-linear dynamic environmental constraints. In a two-sector exogenous growth framework we model a stochastic environmental good, exhibiting uncertain ecological responses to environmental change, and describe the economic and environmental trade-offs that ensue for a risk-averse social planner. Allowing for ecological risk tends to slow economic growth if environmental impacts are assumed to increase exponentially as the rate of disturbance increases. Taken in isolation the effects of ecosystem resilience and ecological uncertainty on the rate of natural resource development are ambiguous and depend on normative parameters such as the social planner’s attitude to risk and rate of time preference.

„Ich brauche ein Titelbild für meine Mappe.“ Bildgestützte Internetrecherche und historisches Bildverstehen

Anke John thematisiert in ihrem Aufsatz “Ich brauche ein Titelbild für meine Mappe“. Bildgestützte Internetrecherche und historisches Bildverstehen. Das Hinterfragen von Bildern mit Hilfe des Internets als Teil des Geschichtsunterrichts. Sie stellt beispielhaft die Recherche über ein Bild dar, das einen Lehrbuchtext über die Judenverfolgung illustriert, und kommt so dem Fotografen und den Umständen der Aufnahme auf die Spur. Nach John täten sich für das Analysieren historischer Präsentationen mit dem Internet neue Wege auf und Quellen könnten im Geschichtsunterricht komplexer hinterfragt werden als bisher, was allerdings noch konkrete Vorgehensweisen für den Unterricht erfordere

Nutrient profile labelling: consumers’ perceptions in Germany and Belgium

Growing consumer interest in food and health has motivated the European food industry to provide more simple information on the nutritional composition of foods. In addition to the traditional back-of-pack nutrition table, simplified front-of-pack labels have been introduced by the food industry to allow consumers making better informed and healthier food choices. In this paper, consumers’ perceptions of simplified nutrition information, namely Guideline Daily Amount (GDA) and Traffic light (TL), in Germany and Belgium are explored. Surveys in Germany (147 respondents) and Belgium (128 respondents) were conducted in 2008. Data were analysed by means of descriptive statistics and regression analysis. In both countries, the GDA is the most widely used simplified nutrition label. Whereas most consumers in Belgium indicate a preference for the GDA, in Germany the Traffic light is favoured most. Regression analyses indicate that the predilection for the different labels is affected by sociodemographic characteristics and perceptions towards the respective labels. European nutrition policy makers should be aware of regional differences regarding the perception of simplified nutrition labels. The challenge for international food industries is therefore to raise awareness of the potential function of simplified labels in making informed and healthy food choices among different European consumer groups.Nutrient profile labelling, Nutrition policy, European food industry, Consumer survey., Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

Evolution of Plant Sucrose Uptake Transporters

In angiosperms, sucrose uptake transporters (SUTs) have important functions especially in vascular tissue. Here we explore the evolutionary origins of SUTs by analysis of angiosperm SUTs and homologous transporters in a vascular early land plant, Selaginella moellendorffii, and a non-vascular plant, the bryophyte Physcomitrella patens, the charophyte algae Chlorokybus atmosphyticus, several red algae and fission yeast, Schizosaccharomyces pombe. Plant SUTs cluster into three types by phylogenetic analysis. Previous studies using angiosperms had shown that types I and II are localized to the plasma membrane while type III SUTs are associated with vacuolar membrane. SUT homologs were not found in the chlorophyte algae Chlamydomonas reinhardtii and Volvox carterii. However, the characean algae Chlorokybus atmosphyticus contains a SUT homolog (CaSUT1) and phylogenetic analysis indicated that it is basal to all other streptophyte SUTs analyzed. SUTs are present in both red algae and S. pombe but they are less related to plant SUTs than CaSUT1. Both Selaginella and Physcomitrella encode type II and III SUTs suggesting that both plasma membrane and vacuolar sucrose transporter activities were present in early land plants. It is likely that SUT transporters are important for scavenging sucrose from the environment and intracellular compartments in charophyte and non-vascular plants. Type I SUTs were only found in eudicots and we conclude that they evolved from type III SUTs, possibly through loss of a vacuolar targeting sequence. Eudicots utilize type I SUTs for phloem (vascular tissue) loading while monocots use type II SUTs for phloem loading. We show that HvSUT1 from barley, a type II SUT, reverted the growth defect of the Arabidopsis atsuc2 (type I) mutant. This indicates that type I and II SUTs evolved similar (and interchangeable) phloem loading transporter capabilities independently

High scale impact in alignment and decoupling in two-Higgs doublet models

The two-Higgs doublet model (2HDM) provides an excellent benchmark to study physics beyond the Standard Model (SM). In this work we discuss how the behaviour of the model at high energy scales causes it to have a scalar with properties very similar to those of the SM -- which means the 2HDM can be seen to naturally favor a decoupling or alignment limit. For a type II 2HDM, we show that requiring the model to be theoretically valid up to a scale of 1 TeV, by studying the renormalization group equations (RGE) of the parameters of the model, causes a significant reduction in the allowed magnitude of the quartic couplings. This, combined with $B$-physics bounds, forces the model to be naturally decoupled. As a consequence, any non-decoupling limits in type II, like the wrong-sign scenario, are excluded. On the contrary, even with the very constraining limits for the Higgs couplings from the LHC, the type I model can deviate substantially from alignment. An RGE analysis similar to that made for type II shows, however, that requiring a single scalar to be heavier than about 500 GeV would be sufficient for the model to be decoupled. Finally, we show that not only a 2HDM where the lightest of the CP-even scalars is the 125 GeV one does not require new physics to be stable up to the Planck scale but this is also true when the heavy CP-even Higgs is the 125 GeV and the theory has no decoupling limit for the type I model.Comment: 28 pages, 19 figure

Emergence of a Dynamic Super-Structural Order Integrating Antiferroelectric and Antiferrodistortive Competing Instabilities in EuTiO3

Microscopic structural instabilities of EuTiO3 single crystal were investigated by synchrotron x-ray diffraction. Antiferrodistortive (AFD) oxygen octahedral rotational order was observed alongside Ti derived antiferroelectric (AFE) distortions. The competition between the two instabilities is reconciled through a cooperatively modulated structure allowing both to coexist. The electric and magnetic field effect on the modulated AFD order shows that the origin of large magnetoelectric coupling is based upon the dynamic equilibrium between the AFD - antiferromagnetic interactions versus the electric polarization - ferromagnetic interactions

Soil Heavy Metal(loid) Pollution and Phytoremediation Potential of Native Plants on a Former Gold Mine in Ghana

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Mass Balances of a Drained and a Rewetted Peatland: on Former Losses and Recent Gains

Drained peatlands are important sources of greenhouse gases and are rewetted to curb these emissions. We study one drained and one rewetted fen in terms of losses—and, after rewetting—gains of organic matter (OM), carbon (C), and peat thickness. We determined bulk density (BD) and ash/OM (and C/OM) ratios for 0.5 cm thick contiguous slices from peat monoliths to calculate losses. Whereas one site has lost 28.5 kg OM m−2 corresponding to annual emissions of ~10 t CO2 ha−1 a−1 over 50 years of effective drainage, the other site has lost 102 kg OM m−2, corresponding to an annual loss of ~30 t CO2 ha−1 a−1 for 30 years of intensive drainage and 6 t CO2 ha−1 a−1 during ~225 years of weak drainage before that. Height losses ranged from 43 to 162 cm. In the 20 years after rewetting, 2.12 kg C m−2 was accumulated, equaling an average annual uptake of ~0.4 kg CO2 m−2 a−1. The results indicate that rewetting can lead to carbon accumulation in fens. This sink function is only small compared with the high emissions that are avoided through rewetting

Interactions between co-expressed Arabidopsis sucrose transporters in the split-ubiquitin system

BACKGROUND: The Arabidopsis genome contains nine sucrose transporter paralogs falling into three clades: SUT1-like, SUT2 and SUT4. The carriers differ in their kinetic properties. Many transport proteins are known to exist as oligomers. The yeast-based split ubiquitin system can be used to analyze the ability of membrane proteins to interact. RESULTS: Promoter-GUS fusions were used to analyze the cellular expression of the three transporter genes in transgenic Arabidopsis plants. All three fusion genes are co-expressed in companion cells. Protein-protein interactions between Arabidopsis sucrose transporters were tested using the split ubiquitin system. Three paralogous sucrose transporters are capable of interacting as either homo- or heteromers. The interactions are specific, since a potassium channel and a glucose transporter did not show interaction with sucrose transporters. Also the biosynthetic and metabolizing enzymes, sucrose phosphate phosphatase and sucrose synthase, which were found to be at least in part bound to the plasma membrane, did not specifically interact with sucrose transporters. CONCLUSIONS: The split-ubiquitin system provides a powerful tool to detect potential interactions between plant membrane proteins by heterologous expression in yeast, and can be used to screen for interactions with membrane proteins as baits. Like other membrane proteins, the Arabidopsis sucrose transporters are able to form oligomers. The biochemical approaches are required to confirm the in planta interaction