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 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.
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.
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 world is currently experiencing a major biodiversity crisis due to human activities. A primary concern is the on-going and rapid biological consequences of global climate change. Climate change is impacting alpine landscapes at unprecedented rates, with severe impacts on landscape structure and catchment hydrodynamics, as well as temperature regimes of glacial-fed rivers. Most glaciers are expected to be dramatically reduced and many even gone by the year 2100, concomitantly with changes (timing and magnitude) in temperature and precipitation. These environmental changes are predicted to have strong impacts on the persistence and distribution of alpine organisms, their population structure and community assembly, and, ultimately, ecosystem functioning. However, how alpine biodiversity (aquatic macroinvertebrates in our case) will respond to these changes is poorly understood. Most previous studies predict the presence of species based on the distribution of putatively suitable habitats but ignore biotic traits, such as dispersal, and potential eco-evolutionary responses to such changes. Clearly, accurate predictions on species responses require integrative studies incorporating landscape dynamics with eco-evolutionary processes. The primary goal of the proposed research is to empirically test determinants of alpine macroinvertebrate responses to rapid environmental change mediated by glacial recession. Climate-induced glacial retreat is occurring rapidly and in a replicated fashion (i.e. over multiple catchments and continents), which provides a natural experiment for testing determinants of organismal and species diversity responses to climate change in alpine waters. The responses of alpine aquatic macroinvertebrates are highly important because of their known sensitivity (i.e. response rates) to environmental change and their fundamental role in ecosystem functioning. Using an integrative comparative and experimental approach, we will target the following main question: What are the roles of ecological and evolutionary processes in population level responses of macroinvertebrates to environmental change? The study will take advantage of rapid glacial recession (environmental change) to empirically examine spatio-temporal patterns in species distribution in nature, combined with experimental and population genetics approaches. The data generated will be used to explicitly address the role of eco-evolutionary processes (determinants) on population level responses for selected key species. Spatial and temporal variation in species distribution, phenotypic and genetic variation will be quantified for two stream macroinvertebrates (hemimetabolous mayfly Baetis alpinus, holometabolous caddisfly Allogamus uncatus), and measuring landscape features and physico-chemical parameters along longitudinal transects downstream of glaciers and selected side-slope tributaries (as potential stepping stones for dispersal and colonization).
Current and future global warming will cause the degradation of mountain permafrost, which may strongly influence the stability of permafrost slopes or rock walls with potentially hazardous consequences. Due to the strong heterogeneity of both the thermal regime and the ground composition of mountain permafrost, its response to atmospheric forcing can however be highly variable for different landforms and within short distances. The spatial distribution of ice and liquid water is important for determining the sensitivity of a specific permafrost occurrence to climate change because of their large influence on the pace of temperature changes (by effects of latent heat) and their importance for geotechnical properties of the ground. Detailed knowledge of the material properties and internal structures of frozen ground is therefore an important prerequisite to determine the sensitivity of permafrost to climate change. Except for the active layer ice and water contents and their temporal and spatial variability usually cannot be measured directly. Geophysical methods are sensitive for the ice and liquid water content in the ground. With the proposed collaboration, two similar but complementary approaches to quantify the composition of the ground based on 2D sections of geophysical data will be combined for an improved determination of ice and water contents in permafrost regions. The so-called 4-phase model (4PM) is based on two simple petrophysical relationships for electrical resistivity and seismic velocity and estimates volumetric fractions of ice, water, and air within the pore volume of a rock matrix by jointly using complementary data sets from electric and seismic measurements. Due to inherent ambiguities in the model it is still restricted to specific cases and often allows only a rough estimation of the phase fractions. Major drawbacks of the current 4PM comprise the unsatisfactory discrimination between rock and ice and its under-determinedness, requiring the prescription of the porosity and further parameters. The so-called RSANN model (developed and used by the host institution) uses the technique of simulated annealing (a Monte-Carlo-type stochastic simulation approach) as an optimization tool for the integration of electrical resistivity and P-wave velocity to derive 2D sections of porosity, water saturation and volumetric water content. The simulated annealing technique allows - due to its iterative procedure - more parameters to be predicted instead of being prescribed as in the 4PM. The objective of the proposed collaboration is to combine the advantages of the two algorithms (4PM and RSANN) to overcome the shortcomings of the 4PM in order to improve the reliability of the determined ice and liquid water contents. (...)
Luminescence dating methods using quartz may suffer from i) incomplete optical resetting (bleaching) of the latent signal at deposition, ii) limited saturation dose and,thus, limited time range using UV-A or blue emissions. The project objectives first consists in exploring and separating OSL emissions from quartz of different sensitivity to light and to isolate components suited for specific dating applications with the Linear Modulation technique. Rapid environmental change with or without human impact will be dated more precisely and more reliably using this sophisticated technique. Secondly it is tried to extend the upper dating limit by using orange-red TL emissions (RTL) from quartz extracted from heated samples (e.g., crustal xenoliths from volcanic eruptions) and from sediments which are too old for conventional OSL dating. Both approaches require fundamental research into the luminescence characteristics of (dose-saturated) quartz crystals from different geological origin (granitic, hydrothermal, sedimentary). Objectives in order: 1. Sampling and refining pure quartz from different geological and petrographic environments and from a well-studied last glacial loess section (Nussloch). 2. Investigating basic luminescence characteristics from different quartz of different origin, with focus on OSL components (LM-OSL) and red TL emissions (RTL). 3. Testing improved techniques (LM-OSL) to recognize incomplete or inhomogeneous signal resetting at deposition and to precisely determine the true burial dose. 4. Extending the upper limit of luminescence dating through use of RTL emissions from heated and from sedimentary quartz. 5. Improving and ensuring of dose rate calculations using different low-level methods including modeling of disequilibrium and spatial non-homogeneity if applicable. 6. Comparing dating results from loess with independent chronologies and other high resolution records of rapid climate change.
Global climate change in cryogenic regions has dominated the research agenda recently, as investigators seek ways of identifying the hazards to infrastructure in cold regions to establish distinct uncertainties through a risk based consideration of sensitivity and consequences and thereby mitigate the risk of permafrost degradation. The latest IPCC report states that temperature increased at the top of the permafrost layer in the Arctic by up to 3 C since the 1980s. The permafrost base has been thawing at rates of up to 0.04 m/yr, permafrost degradation is causing changes in land surface characteristics and drainage systems and snow cover has decreased in most regions. This has been greatest at lower elevations, e.g. in Switzerland. Melting massive ice or degrading permafrost is becoming increasingly susceptible to causing initiation of slope instabilities and debris flows, having caused the 1997 Val Pola debris flows in the Italian Alps. Recent instabilities in the Vallée du Du Durnand in Valais and the Bérard Rock Glacier in France, both in 2006, emphasise the growing concern. Clear risks were also identified in Turtmanntal, Val d'Anniviers and Mattertal, where some rock glacier features indicated formation of crevasses and depressions at critical positions in the landform and increased risk of failure through the body of the mountain permafrost. Knowledge of the evolving thermal state and internal structure, as well as the response of permafrost soils to a gradual warming cycle, is necessary. This project focuses on the variations of geotechnical response of Alpine permafrost with time and temperature. The time effects are important, since a rock glacier will flow or creep downhill. Landforms have changed in the smaller rock glaciers in the West Alps, where these are particularly sensitive to warming scenarios. Clearly this may lead to instability. The specific goals are: o to investigate artificially frozen soils in the laboratory to understand the relative influences of stresses, soil-ice content, particle size and shape, strain rate and temperature on the strength and stiffness, particularly within the thawing zone, o to obtain equivalent strength and stiffness data from stored (and future) cored samples of Alpine Permafrost and to compare with those from artificial frozen soil, o to establish relationships between key parameters for both artificial and real mountain permafrost, o to test an existing constitutive law to represent the thermo-hydro-mechanical behaviour of Alpine permafrost, o to obtain relevant parameters for future input to the constitutive model and subsequent numerical analysis of the test data.
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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