Salinity reduces the productivity of cucumber (Cucumis sativus L.) through osmotic and ionic effects. For given atmospheric conditions we hypothesize the existence of an optimal canopy structure at which water use efficiency is maximal and salt accumulation per unit of dry matter production is minimal. This canopy structure optimum can be predicted by integrating physiological processes over the canopy using a functional-structural plant model (FSPM). This model needs to represent the influence of osmotic stress on plant morphology and stomatal conductance, the accumulation of toxic ions and their dynamics in the different compartments of the system, and their toxic effects in the leaf. Experiments will be conducted to parameterize an extended cucumber FSPM. In in-silico experiments with the FSPM we attempt to identify which canopy structure could lead to maximum long-term water use efficiency with minimum ionic stress. The results from in-silico experiments will be evaluated by comparing different canopy structures in greenhouses. Finally, the FSPM will be used to investigate to which extent the improvement of individual mechanisms of salt tolerance like reduced sensitivity of stomatal conductance or leaf expansion can contribute to whole-plant salt tolerance.
In the last decades agricultural policy has gained increasingly in complexity. Nowadays it influences the food and agricultural sector from the global market down to the farm level. Widespread research questions, like the impact of the WTO negotiations on the farm structure, most often require comprehensive modeling frameworks. Thus, different types of models are utilized according to their comparative advantages and combined in a strategically useful way to more accurately represent micro and macro aspects of the food and agricultural sector. Consequently, in recent years we have seen an increase in the development and application of model linkages. Given this background, the overall objective of this subproject is a systematic sensitivity analysis of model linkages that gradually involves more and more characteristics of the linkage and the corresponding transfer of results between models. In addition, the project aims to answer the following specific question: How does structural change at the farm level influence aggregate supply and technical progress? Under which conditions is it possible to derive macro-relationships from micro-relationships? How does the aggregation level influence the model results and how can possible problems be overcome? This procedure is used to quantify the effects and to derive conditions for optimal interaction of the connected models. The analysis is based on the general equilibrium model GTAP (Global Trade Analysis Project) and the farm group model FARMIS (Farm Modelling Information System) which are employed in conjunction to analyze the effects of WTO negotiations on the farm level.
Organotin and especially butyltin compounds are used for a variety of applications, e.g. as biocides, stabilizers, catalysts and intermediates in chemical syntheses. Tributyltin (TBT) compounds exhibit the greatest toxicity of all organotins and have even been characterized as one of the most toxic groups of xenobiotics ever produced and deliberately introduced into the environment. TBT is not only used as an active biocidal compound in antifouling paints, which are designed to prevent marine and freshwater biota from settlement on ship hulls, harbour and offshore installations, but also as a biocide in wood preservatives, textiles, dispersion paints and agricultural pesticides. Additionally, it occurs as a by-product of mono- (MBT) and dibutyltin (DBT) compounds, which are used as UV stabilizer in many plastics and for other applications. Triphenyltin (TPT) compounds are also used as the active biocide in antifouling paints outside Europe and furthermore as an agricultural fungicide since the early 1960s to combat a range of fungal diseases in various crops, particularly potato blight, leaf spot and powdery mildew on sugar beet, peanuts and celery, other fungi on hop, brown rust on beans, grey moulds on onions, rice blast and coffee leaf rust. Although the use of TBT and TPT was regulated in many countries world-wide from restrictions for certain applications to a total ban, these compounds are still present in the environment. In the early 1970s the impact of TBT on nontarget organisms became apparent. Among the broad variety of malformations caused by TBT in aquatic animals, molluscs have been found to be an extremely sensitive group of invertebrates and no other pathological condition produced by TBT at relative low concentrations rivals that of the imposex phenomenon in prosobranch gastropods speaking in terms of sensitivity. TBT induces imposex in marine prosobranchs at concentrations as low as 0,5 ng TBT-Sn/L. Since 1993, for the littorinid snail Littorina littorea a second virilisation phenomenon, termed intersex, is known. In female specimens affected by intersex the pallial oviduct is transformed of towards a male morphology with a final supplanting of female organs by the corresponding male formations. Imposex and intersex are morphological alterations caused by a chronic exposure to ultra-trace concentrations of TBT. A biological effect monitoring offers the possibility to determine the degree of contamination with organotin compounds in the aquatic environment and especially in coastal waters without using any expensive analytical methods. Furthermore, the biological effect monitoring allows an assessment of the existing TBT pollution on the basis of biological effects. Such results are normally more relevant for the ecosystem than pure analytical data. usw.
In Vivo und in vitro Verabreichung von Nahrungsmittelzusatzstoffen (Tartrazin, Gelborange, Amaranth, Benzoesaeure, Sorbinsaeure, Na-Disulfit, K-Disulfit, Glutamat) und von Nahrungsmitteln (Ei, Milch, Nuesse, Fisch, Rohkost, Fleisch, Mehlsorten) an Patienten mit Verdacht auf entsprechende Unvertraeglichkeiten. Symptome: Kopf- und Bauchschmerzen, Asthma, Rhinitis, Diarrhoe, Urticaria, anaphylaktischer Schock. Mit Hilfe der in vitro Provokationen werden Korrelationen zwischen Mediatorenprofilen und der klinischen Symptomatologie hergestellt. Ziel der Untersuchung: Etablierung eines validen, nicht invarsiven, den Patienten nicht gefaehrdenden diagnostischen Verfahrens zur Objektivierung der nahrungsmittelinduzierten pseudoallergischen Reaktionen.
Our long term activities aim at a functional understanding of alpine plant life. Overall our research shifted gradually from studying resource acquisition (e.g. photosynthesis) toward resource investment and questions of developement. As with treeline, sink activity seems to be the major determinant of growth. A common misconception associated with alpine plant life finds its expression in the use of the terms 'stress' and 'limitation'. See the critique in: Körner C (1998) Alpine plants: stressed or adapted? In: Press MC, Scholes JD, Barker MG (eds.) Physiological Plant Ecology. Blackwell Science , 297-311. Ongoing experimental work: The influence of photoperiod on growth and development in high elevation taxa (Ph.D. by Franziska Keller in cooperation with the Dept. of Geography, University of Fribourg). We test, whether and which species are responsive to earlier snow melt. It appears there exists a suite of different sensitivities, suggesting biodiversity shifts. We also tested the influence of nutrient addition on high elevation pioneer plants and run a longer term project on the interactive effect on sheep tramplng, nitrogen deposition and warming as part of the Swiss National Project NFP 48. A Europe-wide assessment of ground temperatures in alpine grassland is part of ALPNET (see associated organisations). The assessment provides a basis for comparing biodiversity in alpine biota from 69 to 37 degree of northern latitude. (Nagy et al. (2003) Ecological Studies, Vol. 167. 577 p. Springer, Berlin). A synthesis of research in functional ecology of alpine plants over the past 100 years was published in 1999.
The main objective of the project is to determine growth sensitivity, elasticity, and resilience of Douglas-fir provenances to climatic alterations, in particular drought events. To differentiate between the impact of site and genetics, samples from experiments will be analyzed, where identical provenances are planted at different sites. Major research scopes are: Investigating the impact of weather on intra-annual growth patterns We will determine how weather variations affect the provenances' growth. The focus will be on intra-annual variations in wood anatomy and density. A dendrometer study will complement the retrospective analyses to monitor changes in stem hydraulic status and to trace the seasonal timing of growth processes. Fitting genotype- and climate-sensitive growth models for a growth simulation system Retrospective inter-annual growth address long-term trends as well as the effect of distinct climate events on inter-annual growth responses. The goal is to build provenance- and climate-sensitive growth models that can be integrated into a growth simulation system. The assessment of growth responses to drought will be tested and interpreted against the results of the partner projects within the general research concept 'adaptation of forest trees to climatic change - diversity of drought responses in Douglas-fir provenances': P1 (genes), P2 (stable isotopes), and P4 (isoprenoids). A major contribution of our project is to provide the partner projects with research opportunities in the adult stands of the provenance experiments.
The PAGES (Past Global Changes) project, including the PAGES International Project Office in Bern, is funded by the Swiss and U.S. National Science Foundations. The current four-year grant runs from 2006-2010. PAGES was founded in 1991 and works to coordinate international paleoscience research, communicate with the paleoscience community, and integrate past global change scientists from around the world into an international network OBJECTIVES AND METHODS: PAGES is a core project of the International Geosphere Biosphere Program (IGBP) and deals with the Earth's climatic and environmental history from the last few 100 years to several 100,000 years. The primary objective of PAGES is to improve our understanding of past climate and environmental change. SCIENTIFIC AREAS OF INTEREST: While PAGES itself is not a research institution, it helps to identify overarching issues in past global change science and ensure that they are addressed in a coherent manner. Four sets of questions of prime current interest will be targeted by PAGES during the coming years: 1. Climate Forcing and Sensitivity: What is the history of the main climate forcing factors (changes in solar irradiation due to changes in the Earth orbit, changes in solar irradiance due to variability in solar activity, variability of greenhouse gas concentration in the atmosphere, influence of volcanic activity, etc.) and the sensitivity of the climate system to these forcings? In what precise sequence have changes in forcings, surface climate, and ecological systems occurred? 2. Regional Climate Variability: How have global climate and the Earth's natural environment changed in the past? What are the main modes of variability that operated at different timescales, and how do they relate to each other and to the mean state of the climate system? 3. Earth System Dynamics: How have different parts of the Earth System interacted to produce climatic and environmental feedbacks on regional and global scale? What are the causes and thresholds of rapid transitions between quasi-stable climatic and environmental states, in particular on timescales that are relevant to society? How reversible are these changes? 4. Past Human-Climate-Ecosystem Interactions: To what extent and since when has human activity modified climate and the global/regional environment? How can human induced change be disentangled from natural responses to external forcing mechanisms and internal system dynamics? These questions are addressed through organized scientific activities under the umbrella of PAGES. The activities are carried out by the worldwide past global change community, the PAGES Scientific Steering Committee and the PAGES IPO, often in collaboration with other global change programs.
Climate models predict more frequent and more severe extreme events in Europe during the next decades. The potential impact of extended drought periods on agricultural production represents a key aspect in this context. Drought causes metabolic changes in cereals related to protein metabolism (alterations in protein synthesis and adaptation of the protein pattern, protein degradation). The relation of these changes to yield quantity and quality is not yet well understood. Plant exposure to various environmental stresses often leads to the synthesis of stress-inducible proteins with chaperonine functions, dehydrins or proteases. The relationship among the stress-inducible proteins is very important for the survival of plants during drought stress and for the subsequent recovery phase. One of the major signals to be considered during drought stress is the plant hormone abscisic acid (ABA). Drought triggers the production of ABA which induces various genes involved in a signaling cascade for the regulation of downstream biochemical protective mechanisms. Wheat (Triticum aestivum L.) is a widely cultivated crop plant with high sensitivity to water deprivation. In view of this, it is important for agricultural practice to understand the relation between the stress-inducible proteins and the growth of wheat varieties differing in their drought sensitivity. The comparison of selected wheat genotypes may be relevant for basic research on one hand (identification of mechanisms and of potentials in wheat lines differing in their drought tolerance) and may be relevant for agronomy on the other hand (selection of wheat lines for agronomic use in a changing climate). A team from the Bulgarian Academy of Sciences (leader: Professor Klimentina Demirevska-Kepova) and a team from the Institute of Plant Sciences of the University of Bern (leader: Prof. Urs Feller) will collaborate in this project. Successful interactions between the two institutions started several years ago. Initially the contacts were restricted to correspondence and the exchange of reprints. In 2002 a direct collaboration started, when Prof. Klimentina Demirevska-Kepova was as a guest researcher for three months at the Institute of Plant Sciences of the University of Bern. Antibodies previously raised by her team in Bulgaria were helpful tools for the joint experiments. This project will allow to intensify the interactions between the two institutions and to involve more scientists from the Bulgarian Academy of Sciences in this collaboration.
Current climate research is challenged by questions on (i) the characteristics of natural climate variability, (ii) the discrimination from anthropogenic forcing, and (iii) ecological, societal and economic risks. Insight into regional climate change is critically important: Instrumental data and high resolution climate reconstructions show that regional climatic trends and extremes strongly exceed changes reported at hemispheric or global scales. Seasonal to annual, quantitative, regional multi-proxy climate reconstructions are fundamental to assess natural (i.e. pre-anthropogenic), forced and stochastic climate variability. Accurate reconstruction with quantified uncertainties of the 'baseline climate' is the precondition for evaluating the sensitivity of the Earth System to different forcing factors, and validating the results of global and regional, past and future climate modelling. In consequence, one of the hotspots of the international research agenda is to assess natural climate variability of the last 1000 years which encompass the 'Medieval Warm Period' and the 'Little Ice Age'. Among the most fundamental conclusions of recent work is the finding that the structure of past climate change in Europe is very different for each of the four seasons of the year. Most significant are deviations during fall, winter and spring, precisely during the seasons that are poorly or not recorded in natural climate archives. Thus new cold-season proxies are critically important and need to be explored. This is where our project and the new equipment come in. The innovation and novelty of our research is that, besides the classic lake-sediment proxies, Chrysophyte stomatocysts (microfossils produced by 'golden algae') are used for quantitative temperature reconstruction. Recent pioneering work has shown that stomatocysts in Alpine lakes are among the very few proxies and the only 'terrestrial' microfossils that allow quantitative winter/spring temperature reconstructions. This information is unique and has a great potential to evolve into the key parameter for cold-season climate reconstructions. Primary target archive for our research is Lake Silvaplana, a lake with 3500 years of varved sediments. High-quality analysis of stomatocysts requires scanning electron microscopy (acquisition of equipment subject to this proposal). International cutting-edge research calls for continuous, high resolution (annual) sampling. Consequently our research plan has two goals: (i) to optimize the efficiency of data collection with automated image acquisition and off-line image analysis, and (ii) to produce annual winter/spring temperature series for the last 1000 years.
In den zurückliegenden 1.5 Jahren des Projektes konzentrierten sich die Arbeiten auf das erste bereits fertiggestellte vertikale Seismometer-Array des ICDP-GONAF-Observatoriums auf der Tuzla Halbinsel im Südosten Istanbuls. Aufgrund des verbesserten Signal-Rausch-Verhältnisses an den Bohrlochseismometern im Vergleich zu den Oberflächenstationen war es möglich, deutlich mehr M kleiner als 0 Mikrobeben zu detektieren. Diese Messdaten stellten die Grundlage für die bereits durchgeführten seismologischen Studien dar. In der hier beantragten Verlängerung werden wir unsere Erdbebendatenbank für das östliche Marmarameer fortlaufend erweitern, indem wir die im Sommer 2014 fertig gestellten Seismometer-Arrays auf der Armutlu-Halbinsel in die Detektionsalgorithmen integrieren, sowie dann auch weitere vier GONAF-Bohrlocharrays, deren Fertigstellung bis Frühjahr 2015 geplant ist. Es wurden verschiedene Methoden zur Bestimmung oberflächennaher Eigenschaften des Tuzla-Standortes, wie z.B. seismische Geschwindigkeiten und Dämpfung, angewendet und angepasst. Dieselben Methoden werden auf die neuen GONAF-Stationen übertragen, um zu verifizieren, ob die Beobachtungen in Tuzla standortspezifisch, oder auch für andere geologische Formationen repräsentativ sind. Die dann erstmals durchgeführte vergleichende Analyse unterschiedlicher Standorte in der Region wird neue Einblicke geben, um die Auswerteverfahren für die Korrektur von Standort-Effekten weiterzuentwickeln. Dies ist z.B. für eine genaue Abschätzung von Erdbeben-Quellparametern essentiell. Darüber hinaus planen wir, Processing-Methoden des Vertical-Seismic Profiling einzusetzen, um die Zweige der Nordanatolischen Verwerfungszone unterhalb des östlichen Marmarameeres abzubilden (passive fault-zone imaging). Dabei wird die lokale Seismizität genutzt, die in kleiner als 20 km Epizentralentfernung von den GONAF-Stationen in Tiefen von 5 bis 20 km auftritt und an den verschiedenen Tiefenstockwerken der GONAF-Arrays registriert wird. Schließlich werden Wellenformen-Registrierungen von erstmals in 300m Tiefe eingesetzten 3-Komponenten 1Hz MARK Seismometern ausgewertet, unter Anderem um verstärkt S-Wellen-Eigenschaften der Region zu untersuchen.
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