Erprobung und Bewertung eines neuen Geräts zur Unterstockpflege (SIEGWALD HS 1200) im ökologischen Weinbau

A new system for under-vine cultivation (SIEGWALD HS 1200) was tested over a period of two years in four farms with organic viticulture and compared with their customary systems. The SIEGWALD system has well proved its worth. The total costs were comparable to those of other systems. All tractors met the requirements of the SIEGWALD system. Vine trunks were not injured, except in one vineyard. Negative consequences for the fauna on the soil surface and for predatory mites (Typhlodromus pyri) in the canopy were not found

Investigation of planetary ionospheres

Feasibility of using radio sounding techniques to investigate ionospheric properties of planet

Lamb Shift of 3P and 4P states and the determination of α\alpha

The fine structure interval of P states in hydrogenlike systems can be determined theoretically with high precision, because the energy levels of P states are only slightly influenced by the structure of the nucleus. Therefore a measurement of the fine structure may serve as an excellent test of QED in bound systems or alternatively as a means of determining the fine structure constant $\alpha$ with very high precision. In this paper an improved analytic calculation of higher-order binding corrections to the one-loop self energy of 3P and 4P states in hydrogen-like systems with low nuclear charge number $Z$ is presented. A comparison of the analytic results to the extrapolated numerical data for high $Z$ ions serves as an independent test of the analytic evaluation. New theoretical values for the Lamb shift of the P states and for the fine structure splittings are given.Comment: 33 pages, LaTeX, 4 tables, 4 figure

Coordinate-space approach to the bound-electron self-energy: Self-Energy screening calculation

The self-energy screening correction is evaluated in a model in which the effect of the screening electron is represented as a first-order perturbation of the self energy by an effective potential. The effective potential is the Coulomb potential of the spherically averaged charge density of the screening electron. We evaluate the energy shift due to a $1s_{1/2}$, $2s_{1/2}$, $2p_{1/2}$, or $2p_{3/2}$ electron screening a $1s_{1/2}$, $2s_{1/2}$, $2p_{1/2}$, or $2p_{3/2}$ electron, for nuclear charge Z in the range $5 \le Z\le 92$. A detailed comparison with other calculations is made.Comment: 54 pages, 10 figures, 4 table

QED self-energy contribution to highly-excited atomic states

We present numerical values for the self-energy shifts predicted by QED (Quantum Electrodynamics) for hydrogenlike ions (nuclear charge $60 \le Z \le 110$) with an electron in an $n=3$, 4 or 5 level with high angular momentum ($5/2\le j \le 9/2$). Applications include predictions of precision transition energies and studies of the outer-shell structure of atoms and ions.Comment: 20 pages, 5 figure

Toward high-precision values of the self energy of non-S states in hydrogen and hydrogen-like ions

The method and status of a study to provide numerical, high-precision values of the self-energy level shift in hydrogen and hydrogen-like ions is described. Graphs of the self energy in hydrogen-like ions with nuclear charge number between 20 and 110 are given for a large number of states. The self-energy is the largest contribution of Quantum Electrodynamics (QED) to the energy levels of these atomic systems. These results greatly expand the number of levels for which the self energy is known with a controlled and high precision. Applications include the adjustment of the Rydberg constant and atomic calculations that take into account QED effects.Comment: Minor changes since previous versio

Electron Self Energy for Higher Excited S Levels

A nonperturbative numerical evaluation of the one-photon electron self energy for the 3S and 4S states with charge numbers Z=1 to 5 is described. The numerical results are in agreement with known terms in the expansion of the self energy in powers of Zalpha.Comment: 3 pages, RevTeX, to appear in Phys. Rev.

The s-process branching at 185W

The neutron capture cross section of the unstable nucleus 185W has been derived from experimental photoactivation data of the inverse reaction 186W(gamma,n)185W. The new result of sigma = (687 +- 110) mbarn confirms the theoretically predicted neutron capture cross section of 185W of sigma = 700 mbarn at kT = 30 keV. A neutron density in the classical s-process of n_n = (3.8 +0.9 -0.8} * 1e8 cm-3 is derived from the new data for the 185W branching. In a stellar s-process model one finds a significant overproduction of the residual s-only nucleus 186Os.Comment: ApJ, in pres

The economics of potato crop rotations in southern Manitoba

Non-Peer ReviewedRapid expansion of the potato industry in Manitoba has led to increased potato production in Manitoba. While the introduction of potatoes into current cropping systems may provide an opportunity for producers to increase the profitability of their farming operation, development of economically and environmentally sustainable production systems is key to the long-term success of the industry. Currently, little information is available about the economic and environmental impacts of such crop rotations with respect to potato production in Canada. Recognizing the importance of sustainable production systems, in 1998, a potato crop rotation study was established at Manitoba Crop Diversification Center (MCDC) at Carberry to develop recommendations for irrigated potato management in southern Manitoba. Six crop rotations ranging from two to four years in duration, and containing potatoes in combination with oilseed, cereal and/or legume crops, were included in this study. Each phase of each rotation was present in each year making a total of 18 treatments. This paper discusses the economic return of these six different crop rotations. The data with respect to all the production practices, including storage, transport and marketing for the period of 1998 to 2001 were collected and analyzed using a computer model developed for this purpose. Econometrics View software was used to develop this model, and the model takes into account the whole system for each rotation when analyzing the data. The preliminary results suggest that, for the period of 1999 through 2000, both potato-canola and potato-oat-wheat rotations appeared to be promising rotations. However, the poor potato yield of the potato-oatwheat rotation in 2001 resulted in low average net income for that rotation. The higher net benefit of the potato-canola rotation during the time period analyzed was primarily the result of a higher proportion of the tuber yield being of marketable size, not for higher gross tuber or canola yields. It is, however, difficult to make firm conclusions at this point of time as to which rotation will be most profitable in the long term. This is mainly because of the rotation treatments have only been in place since 1998 and, as such, observed differences among rotations may be a function not only of the rotation but also of environmental conditions and management within a given year