On Fermionic Shadow Wave Functions for strongly-correlated multi-reference systems based on a single Slater determinant

We demonstrate that extending the Shadow Wave Function to fermionic systems facilitates to accurately calculate strongly-correlated multi-reference systems such as the stretched H2 molecule. This development considerably extends the scope of electronic structure calculations and enables to efficiently recover the static correlation energy using just a single Slater determinant.Comment: 6 pages, 2 figure

Contraception: answers of wives and husbands compared in a survey of Swiss couples

In a survey of Swiss couples, the husband-wife agreement on contraception (current use, and methods ever used) is high and husbands are generally as well informed on the use of contraceptive methods as their wives. The data indicate that the use of condoms may be underestimated in interviewing women only and that the contraceptive behaviour of a couple is related to the fertility preferences of both wife and husban

Cavity-enhanced optical Hall effect in two-dimensional free charge carrier gases detected at terahertz frequencies

The effect of a tunable, externally coupled Fabry-P\'{e}rot cavity to resonantly enhance the optical Hall effect signatures at terahertz frequencies produced by a traditional Drude-like two-dimensional electron gas is shown and discussed in this communication. As a result, the detection of optical Hall effect signatures at conveniently obtainable magnetic fields, for example by neodymium permanent magnets, is demonstrated. An AlInN/GaN-based high electron mobility transistor structure grown on a sapphire substrate is used for the experiment. The optical Hall effect signatures and their dispersions, which are governed by the frequency and the reflectance minima and maxima of the externally coupled Fabry-P\'{e}rot cavity, are presented and discussed. Tuning the externally coupled Fabry-P\'{e}rot cavity strongly modifies the optical Hall effect signatures, which provides a new degree of freedom for optical Hall effect experiments in addition to frequency, angle of incidence and magnetic field direction and strength

Meta-analysis of crop responses to conservation agriculture in sub-Saharan Africa

Conservation agriculture involves reduced or no-tillage, permanent soil cover and crop rotations to enhance soil fertility and crop yields. Conservation agriculture practices are increasingly promoted on smallholder farms in sub-Saharan Africa as a means to overcome continuing poor-profitability and soil degradation. In recent years a growing number of studies have been carried out in sub-Saharan Africa comparing conservation agriculture practices to conventional tillage-based practices. These studies have been conducted under a range of conditions (climate, soil, management, cropping system) gaining variable results on crop yield responses. The aim of this study is to compare and combine the results from different conservation agriculture experiments using meta-analysis in the hope of identifying patterns among study results, sources of disagreement among those results, or interesting relationships that may come to light in the context of the different studies

Multivalent 1,2,3‐Triazole‐Linked Carbohydrate Mimetics by Huisgen–Meldal‐Sharpless Cycloadditions of an Azidopyran

Starting from an enantiopure 3‐azido‐substituted pyran derivative and various oligo‐alkynes a series of multivalent 1,2,3‐triazole‐linked carbohydrate mimetics was synthesized. The copper‐catalyzed Huisgen–Meldal‐Sharpless cycloaddition (CuAAC) served as key coupling reaction. Cu/C in the presence of triethylamine proved to be a good catalytic system in most cases. Tri‐, tetra‐, hexa‐, and octavalent compounds with typical rigid or flexible core units were prepared. The most complex compound contains a C60‐fullerene center leading to a dodecavalent carbohydrate mimetic. Only a few of the multivalent target compounds could be converted into pure O‐sulfated derivatives that are required for their evaluation as L‐ and P‐selectin ligands. Nevertheless, preliminary experiments suggest that the dodecavalent C60‐derived compound may be a promising ligand of these biologically important proteins with IC50 values in the low nanomolar range

Effectiveness of proximal tibial tubercle transfer in patients with patella baja after total knee arthroplasty

PURPOSE Patella baja after total knee arthroplasty (TKA) is a common problem that is usually treated via proximal transfer of the tibial tubercle. As the long-term outcomes of this procedure are unclarified, this study aimed to investigate the changes in clinical function and radiographic patellar height during five years of follow-up. METHODS Sixty patients with patella baja after TKA who underwent proximalisation of the tibial tubercle were followed up for a mean of 71 months (range 21-153 months). The pre- and postoperative range of motion (ROM) and clinical scores (Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)) were compared. The radiographic patellar height was measured with the Caton-Deschamps index (CDI), Blackburne-Peel ratio (BP), and modified Insall-Salvati index (MIS). RESULTS Proximalisation of the tibial tubercle resulted in a significant improvement in the ROM from 80° to 88°. The KSS and WOMAC did not improve or even worsened after the intervention. The radiographic patellar height immediately after tibial tubercle transfer was not better than prior to the intervention (CDI 0.72 vs. 0.63, p = 0.72; BP 0.66 vs. 0.61, p = 0.72; MIS 1.59 vs. 1.55, p = 1.00) and further decreased significantly so that the mean final values were worse than the values in the native joint (CDI 0.59 vs. 0.78, p = 0.001; BP 0.58 vs. 0.74, p = 0.001; MIS 1.39 vs. 1.81, p < 0.001). CONCLUSION Proximalisation of the tibial tubercle in patients with patella baja after TKA does neither lead to significant improvements in the clinical outcome nor in the radiographic patellar height during long-term follow-up. LEVEL OF EVIDENCE III

Quantum critical dynamics of a S = 1/2 antiferromagnetic Heisenberg chain studied by 13C-NMR spectroscopy

We present a 13C-NMR study of the magnetic field driven transition to complete polarization of the S=1/2 antiferromagnetic Heisenberg chain system copper pyrazine dinitrate Cu(C_4H_4N_2)(NO_3)_2 (CuPzN). The static local magnetization as well as the low-frequency spin dynamics, probed via the nuclear spin-lattice relaxation rate 1/T_1, were explored from the low to the high field limit and at temperatures from the quantum regime (k_B T << J) up to the classical regime (k_B T >> J). The experimental data show very good agreement with quantum Monte Carlo calculations over the complete range of parameters investigated. Close to the critical field, as derived from static experiments, a pronounced maximum in 1/T_1 is found which we interpret as the finite-temperature manifestation of a diverging density of zero-energy magnetic excitations at the field-driven quantum critical point.Comment: 5 pages, 4 figure

Modeling and Simulation of Multi-Lane Traffic Flow

A most important aspect in the field of traffic modeling is the simulation of bottleneck situations. For their realistic description a macroscopic multi-lane model for uni-directional freeways including acceleration, deceleration, velocity fluctuations, overtaking and lane-changing maneuvers is systematically deduced from a gas-kinetic (Boltzmann-like) approach. The resulting equations contain corrections with respect to previous models. For efficient computer simulations, a reduced model delineating the coarse-grained temporal behavior is derived and applied to bottleneck situations.Comment: For related work see http://www.theo2.physik.uni-stuttgart.de/helbing.htm