TY - JOUR A1 - Schlamann, Marc A1 - Voigt, Melanie A. A1 - Maderwald, Stefan A1 - Bitz, Andreas A1 - Kraff, Oliver A1 - Ladd, Susanne C. A1 - Ladd, Mark E. A1 - Forsting, Michael A1 - Wilhelm, Hans T1 - Exposure to high-field MRI does not affect cognitive function JF - Journal of Magnetic Resonance Imaging N2 - Purpose To assess potential cognitive deficits under the influence of static magnetic fields at various field strengths some studies already exist. These studies were not focused on attention as the most vulnerable cognitive function. Additionally, mostly no magnetic resonance imaging (MRI) sequences were performed. Materials and Methods In all, 25 right-handed men were enrolled in this study. All subjects underwent one MRI examination of 63 minutes at 1.5 T and one at 7 T within an interval of 10 to 30 days. The order of the examinations was randomized. Subjects were referred to six standardized neuropsychological tests strictly focused on attention immediately before and after each MRI examination. Differences in neuropsychological variables between the timepoints before and after each MRI examination were assessed and P-values were calculated Results Only six subtests revealed significant differences between pre- and post-MRI. In these tests the subjects achieved better results in post-MRI testing than in pre-MRI testing (P = 0.013–0.032). The other tests revealed no significant results. Conclusion The improvement in post-MRI testing is only explicable as a result of learning effects. MRI examinations, even in ultrahigh-field scanners, do not seem to have any persisting influence on the attention networks of human cognition immediately after exposure. Y1 - 2010 U6 - http://dx.doi.org/10.1002/jmri.22065 SN - 1522-2586 VL - 31 IS - 5 SP - 1061 EP - 1066 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Tippkötter, Nils A1 - Roikaew, Wipa A1 - Ulber, Roland A1 - Hoffmann, Alexander A1 - Denzler, Hans-Jörg A1 - Buchholz, Heinrich T1 - Paracoccus denitrificans for the effluent recycling during continuous denitrification of liquid food JF - Biotechnology Progress N2 - Nitrate is an undesirable component of several foods. A typical case of contamination with high nitrate contents is whey concentrate, containing nitrate in concentrations up to 25 l. The microbiological removal of nitrate by Paracoccus denitrificans under formation of harmless nitrogen in combination with a cell retention reactor is described here. Focus lies on the resource-conserving design of a microbal denitrification process. Two methods are compared. The application of polyvinyl alcohol-immobilized cells, which can be applied several times in whey feed, is compared with the implementation of a two step denitrification system. First, the whey concentrate's nitrate is removed by ion exchange and subsequently the eluent regenerated by microorganisms under their retention by crossflow filtration. Nitrite and nitrate concentrations were determined by reflectometric color measurement with a commercially available Reflectoquant® device. Correction factors for these media had to be determined. During the pilot development, bioreactors from 4 to 250 mg·L-1 and crossflow units with membrane areas from 0.02 to 0.80 m2 were examined. Based on the results of the pilot plants, a scaling for the exemplary process of denitrifying 1,000 tons per day is discussed. Y1 - 2010 U6 - http://dx.doi.org/10.1002/btpr.384 SN - 8756-7938 VL - 26 IS - 3 SP - 756 EP - 762 PB - Wiley CY - Hoboken, NJ ER - TY - JOUR A1 - Orzada, Stephan A1 - Maderwald, Stefan A1 - Poser, Benedikt Andreas A1 - Bitz, Andreas A1 - Quick, Harald H. A1 - Ladd, Mark E. T1 - RF excitation using time interleaved acquisition of modes (TIAMO) to address B1 inhomogeneity in high-field MRI JF - Magnetic Resonance in Medicine N2 - As the field strength and, therefore, the operational frequency in MRI is increased, the wavelength approaches the size of the human head/body, resulting in wave effects, which cause signal decreases and dropouts. Several multichannel approaches have been proposed to try to tackle these problems, including RF shimming, where each element in an array is driven by its own amplifier and modulated with a certain (constant) amplitude and phase relative to the other elements, and Transmit SENSE, where spatially tailored RF pulses are used. In this article, a relatively inexpensive and easy to use imaging scheme for 7 Tesla imaging is proposed to mitigate signal voids due to B1 field inhomogeneity. Two time-interleaved images are acquired using a different excitation mode for each. By forming virtual receive elements, both images are reconstructed together using GRAPPA to achieve a more homogeneous image, with only small SNR and SAR penalty in head and body imaging at 7 Tesla. Y1 - 2010 U6 - http://dx.doi.org/10.1002/mrm.22527 SN - 1522-2594 VL - 64 IS - 2 SP - 327 EP - 333 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Ulber, Roland A1 - Poth, Sebastian A1 - Monzon, Magaly A1 - Tippkötter, Nils T1 - Prozessintegration von Hydrolyse und Fermentation von Cellulose- Faserstoff JF - Chemie Ingenieur Technik N2 - Ein viel versprechender erneuerbarer Rohstoff für die Produktion von Chemikalien und Treibstoffen ist Lignocellulose aus pflanzlicher Biomasse. Die darin enthaltenen Zucker können mittels enzymatischer Hydrolyse freigesetzt und fermentativ zu Ethanol umgesetzt werden. Ein interessanter Ansatz ist dabei die simultane Verzuckerung und Fermentation. Hefen und Enzyme haben mit 30 °C bzw. 50 °C zwar unterschiedliche Temperaturoptima, es konnte aber gezeigt werden, dass auch bei den niedrigeren Temperaturen eine Umsetzung der Cellulose zu Glucose erfolgt, wenn auch langsamer als bei optimalen Bedingungen. Außerdem konnte in Vorversuchen gezeigt werden, dass Ethanol in den zu erwartenden Konzentrationen keinen Einfluss auf die enzymatische Umsetzung hat. Y1 - 2010 U6 - http://dx.doi.org/10.1002/cite.200900103 SN - 1522-2640 N1 - Special Issue "Biokatalyse" VL - 82 IS - 1-2 SP - 135 EP - 139 ER - TY - JOUR A1 - Sieker, Tim A1 - Neuner, Andreas A1 - Dimitrova, Darina A1 - Tippkötter, Nils A1 - Bart, Hans-Jörg A1 - Heinzle, Elmar A1 - Ulber, Roland T1 - Grassilage als Rohstoff für die chemische Industrie JF - Chemie Ingenieur Technik N2 - Grassilage stellt einen nachwachsenden Rohstoff mit großem Potenzial dar. Neben Cellulose und Hemicellulose enthält sie auch organische Säuren, insbesondere Milchsäure. In einem Bioraffinerie-Projekt wird die Milchsäure aus der Silage isoliert und mit gentechnisch optimierten Stämmen zu L-Lysin weiterverarbeitet. Die Lignocellulose wird hydrolysiert und zu Ethanol fermentiert. Ein besonderes Augenmerk liegt auf der Integration der unterschiedlichen Prozesse sowie der einzelnen Prozessschritte zu einem Gesamtprozess, der sämtliche Inhaltsstoffe der Silage verwertet. Y1 - 2010 U6 - http://dx.doi.org/10.1002/cite.201000088 SN - 1522-2640 VL - 82 IS - 8, Special Issue: Industrielle Nutzung nachwachsender Rohstoffe SP - 1153 EP - 1159 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Aggeloussis, Nickos A1 - Giannakou, Erasmia A1 - Albracht, Kirsten A1 - Arampatzis, Adamantios T1 - Reproducibility of fascicle length and pennation angle of gastrocnemius medialis in human gait in vivo JF - Gait and Posture N2 - The purpose of the current study was to examine the reproducibility of fascicle length and pennation angle of gastrocnemius medialis while human walking. To the best of our knowledge, this is the first study of the reproducibility of fascicle length and pennation angle of gastrocnemius medialis in vivo during human gait. Twelve males performed 10 gait trials on a treadmill, in 2 separate days. B-mode ultrasonography, with the ultrasound probe firmly adjusted in the transverse and frontal planes using a special cast, was used to measure the fascicle length and the pennation angle of the gastrocnemius medialis (GM). A Vicon 624 system with three cameras operating at 120 Hz was also used to record the ankle and knee joint angles. The results showed that measurements of fascicle length and pennation angle showed high reproducibility during the gait cycle, both within the same day and between different days. Moreover, the root mean square differences between the repeated waveforms of both variables were very small, compared with their ranges (fascicle length: RMS = ∼3 mm, range: 38–63 mm; pennation angle: RMS = ∼1.5°, range: 22–32°). However, their reproducibility was lower compared to the joint angles. It was found that representative data have to be derived by a wide number of gait trials (fascicle length ∼six trials, pennation angle more than 10 trials), to assure the reliability of the fascicle length and pennation angle in human gait. Y1 - 2010 U6 - http://dx.doi.org/10.1016/j.gaitpost.2009.08.249 SN - 0966-6362 VL - 31 IS - 1 SP - 73 EP - 77 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Arampatzis, Adamantios A1 - Peper, Andreas A1 - Bierbaum, Stefanie A1 - Albracht, Kirsten T1 - Plasticity of human Achilles tendon mechanical and morphological properties in response to cyclic strain JF - Journal of Biomechanics N2 - The purpose of the current study in combination with our previous published data (Arampatzis et al., 2007) was to examine the effects of a controlled modulation of strain magnitude and strain frequency applied to the Achilles tendon on the plasticity of tendon mechanical and morphological properties. Eleven male adults (23.9±2.2 yr) participated in the study. The participants exercised one leg at low magnitude tendon strain (2.97±0.47%), and the other leg at high tendon strain magnitude (4.72±1.08%) of similar frequency (0.5 Hz, 1 s loading, 1 s relaxation) and exercise volume (integral of the plantar flexion moment over time) for 14 weeks, 4 days per week, 5 sets per session. The exercise volume was similar to the intervention of our earlier study (0.17 Hz frequency; 3 s loading, 3 s relaxation) allowing a direct comparison of the results. Before and after the intervention ankle joint moment has been measured by a dynamometer, tendon–aponeurosis elongation by ultrasound and cross-sectional area of the Achilles tendon by magnet resonance images (MRI). We found a decrease in strain at a given tendon force, an increase in tendon–aponeurosis stiffness and tendon elastic modulus of the Achilles tendon only in the leg exercised at high strain magnitude. The cross-sectional area (CSA) of the Achilles tendon did not show any statistically significant (P>0.05) differences to the pre-exercise values in both legs. The results indicate a superior improvement in tendon properties (stiffness, elastic modulus and CSA) at the low frequency (0.17 Hz) compared to the high strain frequency (0.5 Hz) protocol. These findings provide evidence that the strain magnitude applied to the Achilles tendon should exceed the value, which occurs during habitual activities to trigger adaptational effects and that higher tendon strain duration per contraction leads to superior tendon adaptational responses. Y1 - 2010 U6 - http://dx.doi.org/10.1016/j.jbiomech.2010.08.014 SN - 0021-9290 VL - 43 IS - 16 SP - 3073 EP - 3079 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Vogt, C. A1 - Mottaghy, Darius A1 - Wolf, A. A1 - Rath, V. A1 - Pechnig, R. A1 - Clauser, C. T1 - Reducing temperature uncertainties by stochastic geothermal reservoir modelling JF - Geophysical Journal International N2 - Quantifying and minimizing uncertainty is vital for simulating technically and economically successful geothermal reservoirs. To this end, we apply a stochastic modelling sequence, a Monte Carlo study, based on (i) creating an ensemble of possible realizations of a reservoir model, (ii) forward simulation of fluid flow and heat transport, and (iii) constraining post-processing using observed state variables. To generate the ensemble, we use the stochastic algorithm of Sequential Gaussian Simulation and test its potential fitting rock properties, such as thermal conductivity and permeability, of a synthetic reference model and—performing a corresponding forward simulation—state variables such as temperature. The ensemble yields probability distributions of rock properties and state variables at any location inside the reservoir. In addition, we perform a constraining post-processing in order to minimize the uncertainty of the obtained distributions by conditioning the ensemble to observed state variables, in this case temperature. This constraining post-processing works particularly well on systems dominated by fluid flow. The stochastic modelling sequence is applied to a large, steady-state 3-D heat flow model of a reservoir in The Hague, Netherlands. The spatial thermal conductivity distribution is simulated stochastically based on available logging data. Errors of bottom-hole temperatures provide thresholds for the constraining technique performed afterwards. This reduce the temperature uncertainty for the proposed target location significantly from 25 to 12 K (full distribution width) in a depth of 2300 m. Assuming a Gaussian shape of the temperature distribution, the standard deviation is 1.8 K. To allow a more comprehensive approach to quantify uncertainty, we also implement the stochastic simulation of boundary conditions and demonstrate this for the basal specific heat flow in the reservoir of The Hague. As expected, this results in a larger distribution width and hence, a larger, but more realistic uncertainty estimate. However, applying the constraining post-processing the uncertainty is again reduced to the level of the post-processing without stochastic boundary simulation. Thus, constraining post-processing is a suitable tool for reducing uncertainty estimates by observed state variables. Y1 - 2010 U6 - http://dx.doi.org/10.1111/j.1365-246X.2009.04498.x SN - 1365-246X VL - 181 IS - 1 SP - 321 EP - 333 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Butenweg, Christoph A1 - Gellert, Christoph A1 - Schlundt, Andreas T1 - Nichtlinearer Erdbebennachweis von Gebäuden aus Kalksandsteinmauerwerk nach DIN EN 1998 JF - Mauerwerk : European journal of masonry N2 - Die Erdbebensicherheit von Gebäuden aus Kalksandsteinmauerwerk ist aktuell nach DIN 4149 mit linearen Verfahren nachzuweisen. Dies führt in der praktischen Anwendung zu großen Problemen, da selbst traditionell übliche Grundrisse teilweise nicht mehr ohne zusätzliche Maßnahmen nachweisbar sind. Zur Lösung dieser Problematik wurden von der deutschen Mauerwerksindustrie auf nationaler und europäischer Ebene Forschungsprojekte initiiert, deren Ergebnisse in Form von statisch nichtlinearen Verfahren Eingang in den Nationalen Anhang zur DIN EN 1998-1 [12] gefunden haben. Mit den Verfahren wird die Nachweissituation zukünftig grundlegend verbessert, da mit diesen die Tragwerksreserven wesentlich besser ausgenutzt werden können. Im Folgenden wird die Anwendung der Verfahren am Beispiel einer Reihenhauszeile aus Kalksandsteinmauerwerk demonstriert. Der Nachweis der Reihenhäuser wurde im Rahmen einer Zustimmung im Einzelfall, die vom Bundesverband Kalksandsteinindustrie eV in Hannover koordiniert wurde, durch unabhängige Gutachter und die Bauaufsicht eingehend geprüft und für richtig befunden. Die Durchführung des Nachweises erfolgte auf Grundlage eines an der RWTH Aachen entwickelten neuen Nachweiskonzeptes. Die baupraktische Anwendbarkeit und einfache Nachvollziehbarkeit dieses Konzepts ist durch eine softwaretechnische Umsetzung sichergestellt. Y1 - 2010 U6 - http://dx.doi.org/10.1002/dama.201000463 SN - 1432-3427 VL - 14 IS - 3 SP - 120 EP - 125 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Butenweg, Christoph A1 - Fäcke, Andreas A1 - Fehling, Ekkehard A1 - Gellert, Christoph A1 - Gierga, Michael A1 - Meyer, Udo A1 - Rütschlin, Andreas H. A1 - Stürz, Jochen T1 - Energieeffizient und erdbebensicher Bauen mit monolithischem Ziegelmauerwerk JF - Mauerwerk : European journal of masonry N2 - Moderne Bauwerke müssen heute eine hohe energetische Leistungsfähigkeit aufweisen und gleichzeitig alle einwirkenden Lasten sicher abtragen. Dies stellt insbesondere in Erdbebengebieten hohe Anforderungen an die verwendeten Baustoffe. Am baupraktischen Beispiel einer Doppelhaushälfte wird demonstriert, dass die Symbiose aus energieeffizientem und gleichzeitig erdbebensicherem Bauen in der höchsten deutschen Erdbebenzone mit monolithischem Ziegelmauerwerk gut realisierbar ist. Als Ziegelmauerwerk werden für die Außenwände wärmetechnisch optimierte Hochlochziegel verwendet, die sowohl die Anforderungen der Energieeinsparverordnung 2009 als auch die Anforderungen an Mauerwerkbaustoffe nach den aktuellen Erdbebennormen erfüllen. Der Erdbebennachweis der Doppelhaushälfte erfolgt mit einem nichtlinearen Nachweisverfahren, das für eine einfache praktische Anwendung programmtechnisch umgesetzt wurde. Für den Nachweis wurden aus zyklischen Schubwandversuchen ermittelte Last-Verformungskurven verwendet. Das gesamte in Deutschland noch nicht normativ geregelte Nachweiskonzept wurde im Rahmen einer Zustimmung im Einzelfall geprüft und genehmigt. Y1 - 2010 U6 - http://dx.doi.org/10.1002/dama.201000456 SN - 1432-3427 VL - 14 IS - 1 SP - 3 EP - 9 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Kirsch, Ansgar T1 - Experimental investigation of the face stability of shallow tunnels in sand JF - Acta Geotechnica N2 - Various models have been proposed for the prediction of the necessary support pressure at the face of a shallow tunnel. To assess their quality, the collapse of a tunnel face was modelled with small-scale model tests at single gravity. The development of the failure mechanism and the support force at the face in dry sand were investigated. The observed displacement patterns show a negligible influence of overburden on the extent and evolution of the failure zone. The latter is significantly influenced, though, by the initial density of the sand: in dense sand a chimney-wedge-type collapse mechanism developed, which propagated towards the soil surface. Initially, loose sand did not show any discrete collapse mechanism. The necessary support force was neither influenced by the overburden nor the initial density. A comparison with quantitative predictions by several theoretical models showed that the measured necessary support pressure is overestimated by most of the models. Those by Vermeer/Ruse and Léca/Dormieux showed the best agreement to the measurements. Y1 - 2010 U6 - http://dx.doi.org/10.1007/s11440-010-0110-7 SN - 1861-1125 VL - 5 IS - 1 SP - 43 EP - 62 PB - Springer CY - Berlin ER - TY - JOUR A1 - Bolik, Andreas A1 - Linzbach, Meike T1 - Verluste und Zinsschranke in der Bilanzierung latenter Steuern JF - Deutsches Steuerrecht : DStR ; Wochenschrift & umfassende Datenbank für Steuerberater ; Steuerrecht, Wirtschaftsrecht, Betriebswirtschaft, Beruf ; Organ der Bundessteuerberaterkammer N2 - Latente Steuern stellen eine Schnittstelle zwischen handelsrechtlicher Rechnungslegung und Steuerrecht dar. Das Verhältnis von Handels- und Steuerrecht ist dabei keinesfalls stetig; vielmehr fordert die Dynamik des deutschen Steuerrechts in vielen Bereichen regelmäßige Anpassungen in der Bilanzierung in Handels- und Steuerbilanz. Dies gilt insbesondere für die Bilanzierung latenter Steuern im handelsrechtlichen Jahresabschluss, welche durch das BilMoG deutlich an Bedeutung gewonnen hat. Neben latenten Steuern auf temporäre Differenzen ist es nunmehr erforderlich, Verlustvorträge und die Folgen der Zinsschranke bei der Berechnung latenter Steuern zu berücksichtigen. Der nachfolgende Beitrag geht auf die Berücksichtigung von Verlust- und Zinsvorträgen und die Berücksichtigungsfähigkeit von EBITDA-Vorträgen bei der Berechnung latenter Steuern ein und beleuchtet dabei insbesondere auch praktische Fragestellungen. Y1 - 2010 SN - 0012-1347 VL - 48 IS - 31 SP - 1587 EP - 1590 PB - Beck CY - München ER - TY - JOUR A1 - Fellin, Wolfgang A1 - King, Julian A1 - Kirsch, Ansgar A1 - Oberguggenberger, Michael T1 - Uncertainty modelling and sensitivity analysis of tunnel face stability JF - Structural safety N2 - This paper proposes an approach to the choice and evaluation of engineering models with the aid of a typical application in geotechnics. An important issue in the construction of shallow tunnels, especially in weak ground conditions, is the tunnel face stability. Various theoretical and numerical models for predicting the necessary support pressure have been put forth in the literature. In this paper, we combine laboratory experiments performed at the University of Innsbruck with current methods of uncertainty and sensitivity analysis for assessing adequacy, predictive power and robustness of the models. The major issues are the handling of the twofold uncertainty of test results and of model predictions as well as the decision about what are the influential input parameters. Y1 - 2010 U6 - http://dx.doi.org/10.1016/j.strusafe.2010.06.001 SN - 0167-4730 VL - 32 IS - 6 SP - 402 EP - 410 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Fleischhaker, Robert A1 - Evers, Jörg A1 - Dey, Tarak N. T1 - Phase modulation induced by cooperative effects in electromagnetically induced transparency JF - Physical Review A - Atomic, molecular, and optical physics N2 - We analyze the influence of dipole-dipole interactions in an electromagnetically induced transparency set up for a density at the onset of cooperative effects. To this end, we include mean-field models for the influence of local-field corrections and radiation trapping into our calculation. We show both analytically and numerically that the polarization contribution to the local field strongly modulates the phase of a weak pulse. We give an intuitive explanation for this local-field-induced phase modulation and demonstrate that it distinctively differs from the nonlinear self-phase-modulation that a strong pulse experiences in a Kerr medium. Y1 - 2010 U6 - http://dx.doi.org/10.1103/PhysRevA.82.013815 SN - 1050-2947 VL - 82 IS - 1 PB - AIP Publishing CY - Melville, NY ER - TY - JOUR A1 - Mottaghy, Darius A1 - Pechnig, Renate A1 - Taugs, Renate A1 - Kröger, Jens A1 - Thomsen, Claudia A1 - Hesse, Fabian A1 - Liebsch-Doerschner, Thomas T1 - Erstellung eines geothermischen Modells für Teile Hamburgs und anliegende Gebiete JF - BBR - Fachmagazin für Brunnen- und Leitungsbau Y1 - 2010 SN - 1611-1478 VL - 61 IS - 12 SP - 52 EP - 59 PB - WVGW Wirtschafts- u. Verl.Ges. Gas und Wasser CY - Bonn ER - TY - JOUR A1 - Butenweg, Christoph T1 - Bewertung der Erdbebensicherheit von bestehenden Bauwerken JF - Österreichische Ingenieur- und Architekten-Zeitschrift : ÖIAZ ; Zeitschr. d. ÖIAV / Österreichischer Ingenieur- und Architekten-Verein Y1 - 2010 SN - 0721-9415 VL - 155 IS - 1-3 und 4-6 SP - 11 EP - 17 PB - ÖAIV CY - Wien ER - TY - JOUR A1 - Fonti, Patrick A1 - von Arx, Georg A1 - García-González, Ignacio A1 - Eilmann, Britta A1 - Sass-Klaassen, Ute G. W. A1 - Gärtner, Holger A1 - Eckstein, Dieter T1 - Studying global change through investigation of the plastic responses of xylem anatomy in tree rings JF - New Phytologist N2 - Variability in xylem anatomy is of interest to plant scientists because of the role water transport plays in plant performance and survival. Insights into plant adjustments to changing environmental conditions have mainly been obtained through structural and functional comparative studies between taxa or within taxa on contrasting sites or along environmental gradients. Yet, a gap exists regarding the study of hydraulic adjustments in response to environmental changes over the lifetimes of plants. In trees, dated tree-ring series are often exploited to reconstruct dynamics in ecological conditions, and recent work in which wood-anatomical variables have been used in dendrochronology has produced promising results. Environmental signals identified in water-conducting cells carry novel information reflecting changes in regional conditions and are mostly related to short, sub-annual intervals. Although the idea of investigating environmental signals through wood anatomical time series goes back to the 1960s, it is only recently that low-cost computerized image-analysis systems have enabled increased scientific output in this field. We believe that the study of tree-ring anatomy is emerging as a promising approach in tree biology and climate change research, particularly if complemented by physiological and ecological studies. This contribution presents the rationale, the potential, and the methodological challenges of this innovative approach. Y1 - 2010 U6 - http://dx.doi.org/10.1111/j.1469-8137.2009.03030.x SN - 1469-8137 (Online) SN - 0028-646X (Print) VL - 185 IS - 1 SP - 42 EP - 53 PB - Wiley-Blackwell CY - Oxford ER - TY - JOUR A1 - Dobbertin, Matthias A1 - Eilmann, Britta A1 - Bleuler, Peter A1 - Giuggiola, Arnaud A1 - Graf Pannatier, Elisabeth A1 - Landolt, Werner A1 - Schleppi, Patrick A1 - Rigling, Andreas T1 - Effect of irrigation on needle morphology, shoot and stem growth in a drought-exposed Pinus sylvestris forest JF - Tree Physiology N2 - In Valais, Switzerland, Scots pines (Pinus sylvestris L.) are declining, mainly following drought. To assess the impact of drought on tree growth and survival, an irrigation experiment was initiated in 2003 in a mature pine forest, approximately doubling the annual precipitation. Tree crown transparency (lack of foliage) and leaf area index (LAI) were annually assessed. Seven irrigated and six control trees were felled in 2006, and needles, stem discs and branches were taken for growth analysis. Irrigation in 2004 and 2005, both with below-average precipitation, increased needle size, area and mass, stem growth and, with a 1-year delay, shoot length. This led to a relative decrease in tree crown transparency (−14%) and to an increase in stand LAI (+20%). Irrigation increased needle length by 70%, shoot length by 100% and ring width by 120%, regardless of crown transparency. Crown transparency correlated positively with mean needle size, shoot length and ring width and negatively with specific leaf area. Trees with high crown transparency (low growth, short needles) experienced similar increases in needle mass and growth with irrigation than trees with low transparency (high growth, long needles), indicating that seemingly declining trees were able to ‘recover’ when water supply became sufficient. A simple drought index before and during the irrigation explained most of the variation found in the parameters for both irrigated and control trees. Y1 - 2010 U6 - http://dx.doi.org/10.1093/treephys/tpp123 SN - 1758-4469 (Online) SN - 0829-318X (Print) VL - 30 IS - 3 SP - 346 EP - 360 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Eilmann, Britta A1 - Buchmann, Nina A1 - Siegwolf, Rolf A1 - Saurer, Matthias A1 - Cherubini, Paolo A1 - Rigling, Andreas T1 - Fast response of Scots pine to improved water availability reflected in tree-ring width and δ13C JF - Plant, Cell and Environment N2 - Drought-induced forest decline, like the Scots pine mortality in inner-Alpine valleys, will gain in importance as the frequency and severity of drought events are expected to increase. To understand how chronic drought affects tree growth and tree-ring δ13C values, we studied mature Scots pine in an irrigation experiment in an inner-Alpine valley. Tree growth and isotope analyses were carried out at the annual and seasonal scale. At the seasonal scale, maximum δ13C values were measured after the hottest and driest period of the year, and were associated with decreasing growth rates. Inter-annual δ13C values in early- and latewood showed a strong correlation with annual climatic conditions and an immediate decrease as a response to irrigation. This indicates a tight coupling between wood formation and the freshly produced assimilates for trees exposed to chronic drought. This rapid appearance of the isotopic signal is a strong indication for an immediate and direct transfer of newly synthesized assimilates for biomass production. The fast appearance and the distinct isotopic signal suggest a low availability of old stored carbohydrates. If this was a sign for C-storage depletion, an increasing mortality could be expected when stressors increase the need for carbohydrate for defence, repair or regeneration. Y1 - 2010 U6 - http://dx.doi.org/10.1111/j.1365-3040.2010.02153.x SN - 1365-3040 (Online) SN - 0140-7791 (Print) VL - 33 IS - 8 SP - 1351 EP - 1360 PB - Wiley-Blackwell CY - Oxford ER - TY - JOUR A1 - Egli, Simon A1 - Ayer, François A1 - Peter, Martina A1 - Eilmann, Britta A1 - Rigling, Andreas T1 - Is forest mushroom productivity driven by tree growth? Results from a thinning experiment JF - Annals of Forest Science N2 - • Most of the edible forest mushrooms are mycorrhizal and depend on carbohydrates produced by the associated trees. Fruiting patterns of these fungi are not yet fully understood since climatic factors alone do not completely explain mushroom occurrence. • The objective of this study was to retrospectively find out if changing tree growth following an increment thinning has influenced the diversity patterns and productivity of associated forest mushrooms in the fungus reserve La Chanéaz, Switzerland. • The results reveal a clear temporal relationship between the thinning, the growth reaction of trees and the reaction of the fungal community, especially for the ectomycorrhizal species. The tree-ring width of the formerly suppressed beech trees and the fruit body number increased after thinning, leading to a significantly positive correlation between fruit body numbers and tree-ring width. • Fruit body production was influenced by previous annual tree growth, the best accordance was found between fruit body production and the tree-ring width two years previously. • The results support the hypothesis that ectomycorrhizal fruit body production must be linked with the growth of the associated host trees. Moreover, the findings indicate the importance of including mycorrhizal fungi as important players when discussing a tree as a carbon source or sink. Y1 - 2010 U6 - http://dx.doi.org/10.1051/forest/2010011 SN - 1286-4560 (Print) SN - 1297-966X (Online) VL - 67 IS - 5 SP - 509 PB - Springer CY - Paris ER -