Homology fibrations and "group-completion" revisited

We give a proof of the Jardine-Tillmann generalized group completion theorem. It is much in the spirit of the original homology fibration approach by McDuff and Segal, but follows a modern treatment of homotopy colimits, using as little simplicial technology as possible. We compare simplicial and topological definitions of homology fibrations.Comment: 13 page

Quantum states prepared by realistic entanglement swapping

Entanglement swapping between photon pairs is a fundamental building block in schemes using quantum relays or quantum repeaters to overcome the range limits of long-distance quantum key distribution. We develop a closed-form solution for the actual quantum states prepared by realistic entanglement swapping, which takes into account experimental deficiencies due to inefficient detectors, detector dark counts, and multiphoton-pair contributions of parametric down-conversion sources. We investigate how the entanglement present in the final state of the remaining modes is affected by the real-world imperfections. To test the predictions of our theory, comparison with previously published experimental entanglement swapping is provided.Comment: 44 pages, 7 figures, Published with minor changes in Phys. Rev.

Homotopy exponents for large H-spaces

We show that H-spaces with finitely generated cohomology, as an algebra or as an algebra over the Steenrod algebra, have homotopy exponents at all primes. This provides a positive answer to a question of Stanley.Comment: 4 page

Set-up and first operation of a plasma oven for treatment of low level radioactive wastes

An experimental device for plasma treatment of low and intermediate level radioactive waste was built and tested in several design variations. The laboratory device is designed with the intention to study the general effects and difficulties in a plasma incineration set-up for the further future development of a larger scale pilot plant. The key part of the device consists of a novel microwave plasma torch driven by 200 W electric power, and operating at atmospheric pressure. It is a specific design characteristic of the torch that a high peak temperature can be reached with a low power input compared to other plasma torches. Experiments have been carried out to analyze the effect of the plasma on materials typical for operational low-level wastes. In some preliminary cold tests the behavior of stable volatile species e. g., caesium was investigated by TXRF measurements of material collected from the oven walls and the filtered off-gas. The results help in improving and scaling up the existing design and in understanding the effects for a pilot plant, especially for the off-gas collection and treatment

Results of the Prospective Data Collection of 111 Births

Objectives: Does the incidence and/or indication(s) for emergency cesarean section differ if the pregnant woman has an immigrant background (IB)? Does a lack of language proficiency (communication problems) and a low acculturation level result in a longer decision-to-delivery interval (D-D interval)? Are neonates born to women with IB by emergency cesarean section in a poorer condition post delivery? Patient cohorts and method: Standardized interviews were carried out before or immediately after delivery in three Berlin obstetric hospitals. Questions were asked about the sociodemographic background and care aspects as well as about immigration and level of acculturation. Collected data were linked to information obtained from the expectant motherʼs antenatal records and to care data and perinatal data routinely recorded by the hospitals. Data was analyzed using regression models which adjusted for age, parity, and socio-economic status. Results: The total patient population consisted of 7100 women (rate of response: 89.6%); of these women, 111 required emergency cesarean section (50 women without IB, 61 immigrant women). Risk factors such as late first antenatal check-up, gestational diabetes, pregnancy-induced hypertension, fetal macrosomia, smoking, and weight gain were similar in both patient cohorts. The incidence of and indications for emergency cesarean section and the D-D interval were similar for both groups. Limited German language proficiency and low levels of acculturation among immigrant women did not prolong the D-D interval. There were no statistically relevant differences between immigrant and non-immigrant cohorts with regard to adverse neonatal conditions (5-minute Apgar score ≤ 7, umbilical cord arterial pH < 7.00) or with regard to immediate transfer of the neonate to a pediatric clinic following emergency cesarean section. Conclusion: The factor “immigrant background” did not affect the indication or obstetric outcome following emergency cesarean section

Flux creep in the quasi-1D superconducting carbide Sc3CoC4

The superconducting flux dynamic of the transition metal carbide Sc3CoC4 which exhibits a quasi-one-dimensional structure is studied. Besides zero-field-cooling (zfc), field-cooling (fc) and magnetization measurements, especially flux creep relaxation experiments are performed. The relaxation rates S = dM/dlnt are determined at selected temperatures below the transition temperature Tc in two magnetic fields of 50 Oe and 100 Oe just above Hc1. The resulting supercurrent dependence on the mean activation energy is analyzed according to the collective pinning theory which predicts U ∼ ((j/jc)-μ –1). The calculated μ-values differ in the high and low temperature region. The μ-values below about 2.5 K are ≈ 0.5 - 0.68 depending slightly on the applied magnetic field whereas at higher temperatures the μ-values are ≈ 0.22 - 0.34. These results might indicate a transition between different types of vortex pinning around 2.5 K changing from single vortex creep at higher temperatures to collective creep of vortex bundles at lower temperatures