Block-Transitive Designs in Affine Spaces

This paper deals with block-transitive $t$-$(v,k,\lambda)$ designs in affine spaces for large $t$, with a focus on the important index $\lambda=1$ case. We prove that there are no non-trivial 5-$(v,k,1)$ designs admitting a block-transitive group of automorphisms that is of affine type. Moreover, we show that the corresponding non-existence result holds for 4-$(v,k,1)$ designs, except possibly when the group is one-dimensional affine. Our approach involves a consideration of the finite 2-homogeneous affine permutation groups.Comment: 10 pages; to appear in: "Designs, Codes and Cryptography

Uncertainty relations: An operational approach to the error-disturbance tradeoff

The notions of error and disturbance appearing in quantum uncertainty relations are often quantified by the discrepancy of a physical quantity from its ideal value. However, these real and ideal values are not the outcomes of simultaneous measurements, and comparing the values of unmeasured observables is not necessarily meaningful according to quantum theory. To overcome these conceptual difficulties, we take a different approach and define error and disturbance in an operational manner. In particular, we formulate both in terms of the probability that one can successfully distinguish the actual measurement device from the relevant hypothetical ideal by any experimental test whatsoever. This definition itself does not rely on the formalism of quantum theory, avoiding many of the conceptual difficulties of usual definitions. We then derive new Heisenberg-type uncertainty relations for both joint measurability and the error-disturbance tradeoff for arbitrary observables of finite-dimensional systems, as well as for the case of position and momentum. Our relations may be directly applied in information processing settings, for example to infer that devices which can faithfully transmit information regarding one observable do not leak any information about conjugate observables to the environment. We also show that Englert's wave-particle duality relation [PRL 77, 2154 (1996)] can be viewed as an error-disturbance uncertainty relation.Comment: v3: title change, accepted in Quantum; v2: 29 pages, 7 figures; improved definition of measurement error. v1: 26.1 pages, 6 figures; supersedes arXiv:1402.671

Distribution of Complex and Core Lipids within New Hyperthermophilic Members of the Archaea Domain

Core and complex lipids of several new hyperthermophilic archaeal isolates were analyzed. The organisms belong to the Sulfolobales,Archaeoglobus, Pyrobaculum, and Methanococcus. A detailed structural investigation of complex lipids of Pyrobaculum species is reported. The different lipid structures are of help for a rapid and simple phylogenetic classification of the new isolates. They are in agreement with the classification based on other features

A simplex of bound entangled multipartite qubit states

We construct a simplex for multipartite qubit states of even number n of qubits, which has the same geometry concerning separability, mixedness, kind of entanglement, amount of entanglement and nonlocality as the bipartite qubit states. We derive the entanglement of the class of states which can be described by only three real parameters with the help of a multipartite measure for all discrete systems. We prove that the bounds on this measure are optimal for the whole class of states and that it reveals that the states possess only n-partite entanglement and not e.g. bipartite entanglement. We then show that this n-partite entanglement can be increased by stochastic local operations and classical communication to the purest maximal entangled states. However, pure n-partite entanglement cannot be distilled, consequently all entangled states in the simplex are n-partite bound entangled. We study also Bell inequalities and find the same geometry as for bipartite qubits. Moreover, we show how the (hidden) nonlocality for all n-partite bound entangled states can be revealed.Comment: 11 pages, 4 figures; 2nd version changed considerably and a detailed derivation of the multipartite measure is include

Survey of laying hen husbandry in Switzerland

In Switzerland eggs have not been produced in battery cages since January 1992. During the 10 year period from 1981 farmers replaced their battery cages with deep litter, aviary and grid-floor systems and modified cages. However, the cages used to replace the conventional battery cages and most of the grid- floor systems did not fulfil the requirements of the Swiss Welfare Act and they were not permitted to be advertised or sold thereafter. Sixteen years after the ban on battery cages, the Federal Veterinary Office has undertaken a survey to determine how laying hens are kept in Switzerland and how the alternative systems have fared. The survey was carried out on 96 randomly chosen farms with at least 500 hen places to find out more about the housing conditions, management processes, status and performance of hens. The results show that aviaries are very common in Switzerland (65% of the laying hens) and that the laying performance in these systems is significantly higher than that in grid- floor systems and similar to that in battery cages. Provision of a protected outdoor area is a valuable benefit. To be successful with aviary systems it is necessary for pullets to spend the rearing period under similar housing condition