Feuerbrandbekämpfung im ökologischen Obstbau - Ergebnisse der Bekämpfungsversuche 2004

Beim Fachgespräch "Bekämpfung des Feuerbranderregers im Ökologischen Obstbau" am 06.03.2003 in Weinsberg wurde von den anwesenden Experten erhebliche Kenntnislücken zur Wirkungsweise und Wirksamkeit von im ökologischen Obstbau zur Feuerbrandbekämpfung eingesetzten Präparaten festgestellt. Es stand keine verlässliche Bekämpfungsstrategie zur Vermeidung von Blüteninfektionen durch den Feuerbranderreger Erwinia amylovora zur Verfügung. Deshalb wurde im Bundesprogramm ökologischer Landbau ein Forschungsprojekt zur Entwicklung einer Strategie zur Feuerbrandbekämpfung im ökologischen Obstbau genehmigt. Dieses Projekt wird am Lehrstuhl für Phytopathologie der Universität Konstanz in Zusammenarbeit mit der Fördergemeinschaft ökologischer Obstbau und dem Institut für biologischen Pflanzenschutz der BBA durchgeführt. Das Ziel dieses Projektes ist es, Präparate systematisch auf ihre Wirksamkeit und Wirkungsweise gegenüber dem Feuerbranderreger zu untersuchen und anhand der Ergebnisse eine verlässliche Bekämpfungsstrategie zu entwikkeln. Im ersten Versuchsjahr 2004 wurden an zwei Standorten in Süddeutschland 11 Präparate im Freiland geprüft

Feuerbrandbekämpfung im ökologischen Obstbau - Ergebnisse der Bekämpfungsversuche 2006

Seit dem Jahr 2004 läuft innerhalb des Bundesprogramms ökologischer Landbau ein Forschungsprojekt zur Entwicklung einer Strategie zur Feuerbrandbekämpfung im ökologischen Obstbau. Dieses Projekt wird am Lehrstuhl für Phytopathologie der Universität Konstanz in Zusammenarbeit mit der Fördergemeinschaft ökologischer Obstbau und dem Institut für biologischen Pflanzenschutz der BBA in Darmstadt durchgeführt. Ergebnisse aus 2004 und aus 2005 sind in den jeweiligen Dezemberausgaben der Mitteilungen nachzulesen (Ökoobstbau Mitteilungen 4/04 und 3/05, Anmerkung der Redaktion). In 2006 wurden vier Freilandversuche durchgeführt. An zwei Versuchstandorten (Darmstadt und Karsee) wurde der Erreger ausgebracht, so dass die Wirksamkeit von Blossom-Protect im Vergleich zu anderen Präparaten überprüft werden konnte. Hier wurde auch der Einfluss von Schwefelbehandlungen, die zur Schorfbekämpfung notwendig sind, auf die Wirksamkeit von Blossom-Protect untersucht. Zusätzlich wurde in zwei Praxisanlagen (Stetten und Lindau) der Einfluss der Behandlungen auf die Fruchtberostung untersucht

Spin correlations and Dzyaloshinskii-Moriya interaction in Cs2_2CuCl4_4

We report on electron spin resonance (ESR) studies of the spin relaxation in Cs$_2$CuCl$_4$. The main source of the ESR linewidth at temperatures $T \leq 150$ K is attributed to the uniform Dzyaloshinskii-Moriya interaction. The vector components of the Dzyaloshinskii-Moriya interaction are determined from the angular dependence of the ESR spectra using a high-temperature approximation. Both the angular and temperature dependence of the ESR linewidth have been analyzed using a self-consistent quantum-mechanical approach. In addition analytical expressions based on a quasi-classical picture for spin fluctuations are derived, which show good agreement with the quantum-approach for temperatures $T \geq 2J/k_{\rm B} \approx 15$ K. A small modulation of the ESR linewidth observed in the $ac$-plane is attributed to the anisotropic Zeeman interaction, which reflects the two magnetically nonequivalent Cu positions

A fully relativistic radial fall

Radial fall has historically played a momentous role. It is one of the most classical problems, the solutions of which represent the level of understanding of gravitation in a given epoch. A {\it gedankenexperiment} in a modern frame is given by a small body, like a compact star or a solar mass black hole, captured by a supermassive black hole. The mass of the small body itself and the emission of gravitational radiation cause the departure from the geodesic path due to the back-action, that is the self-force. For radial fall, as any other non-adiabatic motion, the instantaneous identity of the radiated energy and the loss of orbital energy cannot be imposed and provide the perturbed trajectory. In the first part of this letter, we present the effects due to the self-force computed on the geodesic trajectory in the background field. Compared to the latter trajectory, in the Regge-Wheeler, harmonic and all others smoothly related gauges, a far observer concludes that the self-force pushes inward (not outward) the falling body, with a strength proportional to the mass of the small body for a given large mass; further, the same observer notes an higher value of the maximal coordinate velocity, this value being reached earlier on during infall. In the second part of this letter, we implement a self-consistent approach for which the trajectory is iteratively corrected by the self-force, this time computed on osculating geodesics. Finally, we compare the motion driven by the self-force without and with self-consistent orbital evolution. Subtle differences are noticeable, even if self-force effects have hardly the time to accumulate in such a short orbit.Comment: To appear in Int. J. Geom. Meth. Mod. Phy

Precision Study of Positronium: Testing Bound State QED Theory

As an unstable light pure leptonic system, positronium is a very specific probe atom to test bound state QED. In contrast to ordinary QED for free leptons, the bound state QED theory is not so well understood and bound state approaches deserve highly accurate tests. We present a brief overview of precision studies of positronium paying special attention to uncertainties of theory as well as comparison of theory and experiment. We also consider in detail advantages and disadvantages of positronium tests compared to other QED experiments.Comment: A talk presented at Workshop on Positronium Physics (ETH Zurich, May 30-31, 2003

Relativistic Hydrodynamics for Heavy--Ion Collisions -- I. General Aspects and Expansion into Vacuum

We present algorithms to solve relativistic hydrodynamics in 3+1--dimensional situations without apparent symmetry to simplify the solution. In simulations of heavy--ion collisions, these numerical schemes have to deal with the physical vacuum and with equations of state with a first order phase transition between hadron matter and a quark--gluon plasma. We investigate their performance for the one--dimensional expansion of baryon-free nuclear matter into the vacuum, which is an analytically solvable test problem that incorporates both the aspect of the vacuum as well as that of a phase transition in the equation of state. The dependence of the lifetime of the mixed phase on the initial energy density is discussed.Comment: 31 pages, 16 uuencoded figure

Scientific, institutional and personal rivalries among Soviet geographers in the late Stalin era

Scientific, institutional and personal rivalries between three key centres of geographical research and scholarship (the Academy of Sciences Institute of Geography and the Faculties of Geography at Moscow and Leningrad State Universities) are surveyed for the period from 1945 to the early 1950s. It is argued that the debates and rivalries between members of the three institutions appear to have been motivated by a variety of scientific, ideological, institutional and personal factors, but that genuine scientific disagreements were at least as important as political and ideological factors in influencing the course of the debates and in determining their final outcome

Flux Modulations seen by the Muon Veto of the GERDA Experiment

The GERDA experiment at LNGS of INFN is equipped with an active muon veto. The main part of the system is a water Cherenkov veto with 66~PMTs in the water tank surrounding the GERDA cryostat. The muon flux recorded by this veto shows a seasonal modulation. Two effects have been identified which are caused by secondary muons from the CNGS neutrino beam (2.2 %) and a temperature modulation of the atmosphere (1.4 %). A mean cosmic muon rate of $I^0_{\mu} = (3.477 \pm 0.002_{\textrm{stat}} \pm 0.067_{\textrm{sys}}) \times 10^{-4}$/(s$\cdot$m$^2$) was found in good agreement with other experiments at LNGS at a depth of 3500~meter water equivalent.Comment: 7 pages, 6 figure

Leptin protects mice from starvation-induced lymphoid atrophy and increases thymic cellularity in ob/ob mice.

Published versio

Spin correlations and Dzyaloshinskii-Moriya interaction in Cs 2CuCl4

We report on electron spin resonance (ESR) studies of the spin relaxation in Cs2CuCl4. The main source of the ESR linewidth at temperatures T≤150 K is attributed to the uniform Dzyaloshinskii-Moriya interaction. The vector components of the Dzyaloshinskii-Moriya interaction are determined from the angular dependence of the ESR spectra using a high-temperature approximation. Both the angular and temperature dependencies of the ESR linewidth have been analyzed using a self-consistent quantum-mechanical approach. In addition, analytical expressions based on a quasiclassical picture for spin fluctuations are derived, which show good agreement with the quantum-approach for temperatures T≥2J/kB≈15 K. A small modulation of the ESR linewidth observed in the ac plane is attributed to the anisotropic Zeeman interaction, which reflects the two magnetically nonequivalent Cu positions. © 2013 American Physical Society