Einfluss der Futterleguminosenart, deren Saatzeit und Nutzung auf die Nachfrucht Winterweizen

The preceding crop effect of fodder legumes concerning sowing date, type of legume and utilization were conducted in field trials at two sites in Upper Bavaria in 2012- 2013. All in all, seven types of clover in pure stands or clover/grass leys were grown one main production year. Sowing dates were undersowings in triticale in spring, stubble seeds after harvest of preceding crop triticale and spring seed in the main production year. Utilization variants were mulching or cutting without organic fertilization in the subsequent crop winter wheat. Mulching of fodder legumes resulted in higher yields and mostly higher baking quality (crude protein content, wet gluten content and baking volume) of the succeeding wheat. Earlier sowings leaded mostly to higher yields and higher baking quality. At species level, a mixture of white clover and black medic showed highest yield as well as highest crude protein and wet gluten contents. It is concluded, that fodder legume management strongly affected the preceding crop effect

Vergleich verschiedener Arten und Saatzeiten bei Futterleguminosen

Sowing date of fodder legumes and type of legume may influence yield and preceding crop effect. Field trials were conducted at two sites in Upper Bavaria in 2010-2012. Seven types of clover in pure stands or clover/grass leys were compared for one main production year. Sowing dates were undersowing triticale in spring, stubble seeds after harvest of preceding crop triticale and spring seed in the main production year. Dry matter and crude protein yields were strongly affected by sowing date and by type of clover. Earlier sowings lead to higher yield of fodder legumes. Crude protein yield for clover/grass ley dominated by lucerne, red and white clover undersown in triticale was nearly twice as high as for spring seed in the main production year. Among this clover/grass ley, red clover in pure stands achieved highest yields at species level

Change of quasiparticle dispersion in crossing T_c in the underdoped cuprates

One of the most remarkable properties of the high-temperature superconductors is a pseudogap regime appearing in the underdoped cuprates above the superconducting transition temperature T_c. The pseudogap continously develops out of the superconducting gap. In this paper, we demonstrate by means of a detailed comparison between theory and experiment that the characteristic change of quasiparticle dispersion in crossing T_c in the underdoped cuprates can be understood as being due to phase fluctuations of the superconducting order parameter. In particular, we show that within a phase fluctuation model the characteristic back-turning BCS bands disappear above T_c whereas the gap remains open. Furthermore, the pseudogap rather has a U-shape instead of the characteristic V-shape of a d_{x^2-y^2}-wave pairing symmetry and starts closing from the nodal k=(pi/2,pi/2) directions, whereas it rather fills in at the anti-nodal k=(pi,0) regions, yielding further support to the phase fluctuation scenario.Comment: 6 pages, 4 eps-figure

Topological equivalence of holomorphic foliation germs of rank 1 with isolated singularity in the Poincar/'e domain

We show that the topological equivalence class of holomorphic foliation germs of rank 1 with an isolated singularity of Poincaré type is determined by the topological equivalence class of the real intersection foliation of the (suitably normalized) foliation germ with a sphere centered in the singularity. We use this Reconstruction Theorem to completely classify topological equivalence classes of plane holomorphic foliation germs of Poincaré type and discuss a conjecture on the classification in dimension ≥3

Phase-fluctuation induced reduction of the kinetic energy at the superconducting transition

Recent reflectivity measurements provide evidence for a "violation" of the in-plane optical integral in the underdoped high-T_c compound Bi_2Sr_2CaCu_2O_{8+\delta} up to frequencies much higher than expected by standard BCS theory. The sum rule violation may be related to a loss of in-plane kinetic energy at the superconducting transition. Here, we show that a model based on phase fluctuations of the superconducting order parameter can account for this change of in-plane kinetic energy at T_c. The change is due to a transition from a phase-incoherent Cooper-pair motion in the pseudogap regime above T_c to a phase-coherent motion at T_c.Comment: 5 pages, 3 eps-figure

Exact ground states for the four-electron problem in a two-dimensional finite Hubbard square system

We present exact explicit analytical results describing the exact ground state of four electrons in a two dimensional square Hubbard cluster containing 16 sites taken with periodic boundary conditions. The presented procedure, which works for arbitrary even particle number and lattice sites, is based on explicitly given symmetry adapted base vectors constructed in r-space. The Hamiltonian acting on these states generates a closed system of 85 linear equations providing by its minimum eigenvalue the exact ground state of the system. The presented results, described with the aim to generate further creative developments, not only show how the ground state can be exactly obtained and what kind of contributions enter in its construction, but emphasize further characteristics of the spectrum. On this line i) possible explications are found regarding why weak coupling expansions often provide a good approximation for the Hubbard model at intermediate couplings, or ii) explicitly given low lying energy states of the kinetic energy, avoiding double occupancy, suggest new roots for pairing mechanism attracting decrease in the kinetic energy, as emphasized by kinetic energy driven superconductivity theories.Comment: 37 pages, 18 figure

Ab initio screening methodology applied to the search for new permanent magnetic materials

In this paper a computational high-throughput screening (HTS) approach to the search for alternative permanent magnetic materials is presented. Systems considered for a start are binary intermetallic compounds composed of rare-earth (RE) and transition metal (TM) elements. With the tight-binding-linear muffin-tin-orbital-atomic-sphere-approximation (TBLMTO-ASA) method of density functional theory (DFT) a variety of RE–TM intermetallic phases is investigated and their magnetic properties are obtained at rather low computational costs. Next, interstitial elements such as boron, carbon and nitrogen in these phases are considered. For promising candidate phases with high and stable spontaneous ferromagnetic polarization, the calculated local magnetic moments and exchange coupling parameters, as obtained from TB-LMTO-ASA calculations, are then used for Monte Carlo simulations to identify candidates with sufficiently high Curie temperatures (Tc). Finally, magnetocrystalline anisotropy constants (K1) of the most promising candidate phases are calculated with accurate, potential-shape-unrestricted DFT calculations using the Vienna ab initio simulation package. The computational HTS procedure is illustrated by results for a selection of hard-magnetic RE–TM phases like RETM5, RE2TM17 and RE2TM14B

Pair Phase Fluctuations and the Pseudogap

The single-particle density of states and the tunneling conductance are studied for a two-dimensional BCS-like Hamiltonian with a d_{x^2-y^2}-gap and phase fluctuations. The latter are treated by a classical Monte Carlo simulation of an XY model. Comparison of our results with recent scanning tunneling spectra of Bi-based high-T_c cuprates supports the idea that the pseudogap behavior observed in these experiments can be understood as arising from phase fluctuations of a d_{x^2-y^2} pairing gap whose amplitude forms on an energy scale set by T_c^{MF} well above the actual superconducting transition.Comment: 5 pages, 6 eps-figure