A concept for quantitative characterization of the air balance in Bavarian forest soils

Site-specific descriptions of soil water balance and soil air balance are important for tree species selection in forestry. We present a concept for describing the soil air balance for Bavaria. It is an enhancement of an empirical multiple linear regression model that explains soil oxygen deficiency in terms of topographic, climate and soil parameters. We modelled numerous combinations of site conditions with the hydrologic model LWF-Brook 90 to determine an estimator for soil oxygen deficiency. This estimator reflects water logging that persists for a certain length of time. In a second step we will develop a new regression model and combine this information with topographical information about additional water fluxes in a GIS. We aim to combine both steps in order to describe the air balance of forest soils for the entirety of Bavaria.Da neben der Beschreibung des Wasserhaushaltes auch die Kenntnis über Luftmangel für die standortgerechte Baumartenwahl wichtig ist, wird ein Konzept für die bayernweite Beschreibung des Lufthaushaltes vorgestellt. Es ist eine Weiterentwicklung eines empirischen Regressionsmodells, das die Staunässe mittels Geländeparametern, Klima und Bodendaten abschätzt. Dazu wurden mit dem Wasserhaushaltsprogramm LWF-Brook 90 zahlreiche Kombinationen von Standortsfaktoren simuliert und eine Schätzgröße für Luftmangel ausgegeben. Diese Größe beschreibt die Einschränkung des Lufthaushaltes über einen längeren Zeitraum. In einem weiteren Schritt wird dieser deterministische Luftmangelparameter über ein neues Regressionsmodell abgeleitet und mit zusätzlichen topographischen Informationen über Zu- und Abflüsse in einem GIS kombiniert. Ziel ist es, für ganz Bayern den Lufthaushalt von Waldböden zu beschreiben

Elektrochemische Untersuchungen zur Porosität von Nanoschichten auf Kohlenstoff-Basis

Die Porosität unterschiedlich hergestellter Schichten auf Kohlenstoff-Basis wurde mit Hilfe der Zyklovoltammetrie untersucht und verglichen. Die Bestimmung der Porosität erfolgte zunächst anhand der Auflösestromdichte des metallischen Substrats, auf dem die verschiedenen Schichtsysteme abgeschieden wurden. Dazu wurde das Schicht/Substrat-System einem für das Substrat Eisen korrosiven Medium ausgesetzt und der Substrat-Auflösestrom durch die Poren hindurch elektrochemisch gemessen. Als Beschichtungsverfahren kamen Aufdampfen mit anschließendem Ionenbeschuss, Plasma-aktivierte Chemische Gasphasenabscheidung sowie die Gasphasenpolymerisation zum Einsatz. Alle diese Prozesse fanden unter Vakuumbedingungen statt, bei niedrigen, substratschonenden Temperaturen. Die erhaltenen Schichten wurden mit Hilfe der Raman-Spektroskopie, Sekundärionen-Massenspektrometrie, Rasterelektronen-Mikroskopie und eines Profilometers in ihren Eigenschaften wie Zusammensetzung, Struktur und Dicke charakterisiert. Anhand der gemessenen Stromdichte-Potenzial-Kurven konnte der Einfluss verschiedener Herstellungsparameter auf die Schichtporosität untersucht werden. Dabei zeigte sich, dass sich die Porosität der meisten untersuchten Schichtsysteme mit zunehmender Schichtdicke verringert, oberhalb einer bestimmten Dicke aber wieder zunimmt, bedingt durch Rissbildung aufgrund von intrinsischem Stress. Nur bei den Polymerschichten aus Poly(para-xylylen) nimmt die Porosität mit zunehmender Schichtdicke stetig ab und es konnten schließlich porenfreie Polymerfilme ab einer Dicke von 700 nm erhalten werden. Des weiteren konnte anhand der in den Zyklovoltammogrammen beobachteten Potenzial-verschiebungen ein Modell entwickelt werden, welches die Verschiebungen erklärt und zudem weitere, komplementäre Informationen über die Gestalt der Poren in der Schicht liefern kann

Phosphorylation of CREB affects its binding to high and low affinity sites

Cyclic AMP treatment of hepatoma cells leads to increased protein binding at the cyclic AMP response element (CRE) of the tyrosine aminotransferase (TAT) gene in vivo, as revealed by genomic footprinting, whereas no increase is observed at the CRE of the phosphoenolpyruvate carboxykinase (PEPCK) gene. Several criteria establish that the 43 kDa CREB protein is interacting with both of these sites. Two classes of CRE with different affinity for CREB are described. One class, including the TATCRE, is characterized by asymmetric and weak binding sites (CGTCA), whereas the second class containing symmetrical TGACGTCA sites shows a much higher binding affinity for CREB. Both classes show an increase in binding after phosphorylation of CREB by protein kinase A (PKA). An in vivo phosphorylation-dependent change in binding of CREB increases the occupancy of weak binding sites used for transactivation, such as the TATCRE, while high affinity sites may have constitutive binding of transcriptionally active and inactive CREB dimers, as demonstrated by in vivo footprinting at the PEPCK CRE. Thus, lower basal level and higher relative stimulation of transcription by cyclic AMP through low affinity CREs should result, allowing finely tuned control of gene activation

Unimagined Imaginary Parts in Heavy Quark Effective Field Theory

We argue that the imaginary parts of the anomalous dimensions in the multiparticle sectors of heavy quark effective field theory may be removed by a suitable redefinition of the multiparticle states. The connection between the imaginary parts of the anomalous dimensions and the interquark potential is pointed outComment: 14 Pages, LaTeX, HUTP-93/A009, IKDA 93/

Party politics at the water's edge:Contestation of military operations in Europe

This paper contributes to current debates on the politicization of international politics by examining party-political contestation of peace and security missions. It is guided by two inter-related questions, (a) to what extent deployment decisions are contested amongst political parties and (b) what drives such contestation. We examine data from a new data set on parliamentary votes on deployment decisions in France, Germany, Spain, and the United Kingdom and from the Chapel Hill Expert Survey. Against conventional wisdom and in an effort to address the often-overlooked role of political parties, we find that military deployments have been systematically contested amongst political parties across Europe. Further, we find that contestation is driven by the left/right axis, as opposed to newer cleavages captured here by the so-called gal/tan axis. We also find evidence that patterns of contestation depend on parties' positions in government or opposition, a factor we relate to bureaucratic and international pressures on the parties in office, and to political opportunities for opposition parties

The Party Politics of Legislative:Executive Relations in Security and Defence Policy

The move from territorial defence to ‘wars of choice’ has influenced the domestic politics of military interventions. This paper examines the extent to which both the substance and the procedure of military interventions are contested among political parties. Regarding the substance, our analysis of Chapel Hill Expert Survey data demonstrates that across European states political parties on the right are more supportive of military missions than those on the left. On the decision-making procedures, our case studies of Germany, France, Spain and the United Kingdom show that political parties on the left tend to favour strong parliamentary control whereas those on the right tend to prefer an unconstrained executive, although with differences across countries. These findings challenge the view that ‘politics stops at the water’s edge’ and contribute to a better understanding of how political parties and parliaments influence military interventions

Climate change and mixed forests: how do altered survival probabilities impact economically desirable species proportions of Norway spruce and European beech?

International audienceKey message Economic consequences of altered survival probabilities under climate change should be considered for regeneration planning in Southeast Germany. Findings suggest that species compositions of mixed stands obtained from continuous optimization may buffer but not completely mitigate economic consequences. Mixed stands of Norway spruce (Picea abiesL. Karst.) and European beech (Fagus sylvaticaL.) (considering biophysical interactions between tree species) were found to be more robust, against both perturbations in survival probabilities and economic input variables, compared to block mixtures (excluding biophysical interactions).ContextClimate change is expected to increase natural hazards in European forests. Uncertainty in expected tree mortality and resulting potential economic consequences complicate regeneration decisions.AimsThis study aims to analyze the economic consequences of altered survival probabilities for mixing Norway spruce (Picea abies L. Karst.) and European beech (Fagus sylvatica L.) under different climate change scenarios. We investigate whether management strategies such as species selection and type of mixture (mixed stands vs. block mixture) could mitigate adverse financial effects of climate change.MethodsThe bio-economic modelling approach combines a parametric survival model with modern portfolio theory. We estimate the economically optimal species mix under climate change, accounting for the biophysical and economic effects of tree mixtures. The approach is demonstrated using an example from Southeast Germany.ResultsThe optimal tree species mixtures under simulated climate change effects could buffer but not completely mitigate undesirable economic consequences. Even under optimally mixed forest stands, the risk-adjusted economic value decreased by 28%. Mixed stands economically outperform block mixtures for all climate scenarios.ConclusionOur results underline the importance of mixed stands to mitigate the economic consequences of climate change. Mechanistic bio-economic models help to understand consequences of uncertain input variables and to design purposeful adaptation strategies

A simple and effective method for the accurate extraction of kinetic parameters using differential Tafel plots

The practice of estimating the transfer coefficient (α) and the exchange current (i0) by arbitrarily placing a straight line on Tafel plots has led to high variance in these parameters between different research groups. Generating Tafel plots by finding kinetic current, ik from the conventional mass transfer correction method does not guarantee an accurate estimation of the α and i0. This is because a substantial difference in values of α and i0 can arise from only minor deviations in the calculated values of ik. These minor deviations are often not easy to recognise in polarisation curves and Tafel plots. Recalling the IUPAC definition of α , the Tafel plots can be alternatively represented as differential Tafel plots (DTPs) by taking the first order differential of Tafel plots with respect to overpotential. Without further complex processing of the existing raw data, many crucial observations can be made from DTP which is otherwise very difficult to observe from Tafel plots. These for example include a) many perfectly looking experimental linear Tafel plots (R2 > 0.999) can give rise to incorrect kinetic parameters b) substantial differences in values of α and i0 can arise when the limiting current (iL) is just off by 5% while performing the mass transfer correction c) irrespective of the magnitude of the double layer charging current (ic), the Tafel plots can still get significantly skewed when the ratio of i0/ic is small. Hence, in order to determine accurate values of α and i0, we show how the DTP approach can be applied to experimental polarisation curves having well defined iL, poorly defined iL and no iL at all

Modelling Dominant Tree Heights of Fagus sylvatica L. Using Function-on-Scalar Regression Based on Forest Inventory Data

European beech (Fagus sylvatica L.) is an important tree species throughout Europe but shifts in its suitable habitats are expected in the future due to climate change. Finding provenances that are still economically viable and ecologically resilient is an ongoing field of research. We modelled the dominant tree heights of European beech as a trait reflecting growth performance dependent on provenance, climate and soil conditions. We derived dominant tree heights from national forest inventory (NFI) data from six European countries spanning over large ecological gradients. We performed function-on-scalar regression using hierarchical generalized additive models (HGAM) to model both the global effects shared among all provenances and the effects specific to a particular provenance. By comparing predictions for a reference period of 1981-2010 and 2071-2100 in a RCP 8.5 scenario, we showed that changes in growth performance can be expected in the future. Dominant tree heights decreased in Southern and Central Europe but increased in Northern Europe by more than 10 m. Changes in growth performance were always accompanied by a change in beech provenances, assuming assisted migration without dispersal limitations. Our results support the concept of assisted migration for the building of resilient future forests and emphasize the use of genetic data for future growth predictions