Quantum Cloning, Eavesdropping and Bell's inequality

We analyze various eavesdropping strategies on a quantum cryptographic channel. We present the optimal strategy for an eavesdropper restricted to a two-dimensional probe, interacting on-line with each transmitted signal. The link between safety of the transmission and the violation of Bell's inequality is discussed. We also use a quantum copying machine for eavesdropping and for broadcasting quantum information.Comment: LaTex, 13 pages, with 6 Postscript figure

Nonlinear quantum state transformation of spin-1/2

A non-linear quantum state transformation is presented. The transformation, which operates on pairs of spin-1/2, can be used to distinguish optimally between two non-orthogonal states. Similar transformations applied locally on each component of an entangled pair of spin-1/2 can be used to transform a mixed nonlocal state into a quasi-pure maximally entangled singlet state. In both cases the transformation makes use of the basic building block of the quantum computer, namely the quantum-XOR gate.Comment: 12 pages, LaTeX, amssym, epsfig (2 figures included

Die infektiöse Spondylitis

Zusammenfasung: Bei der infektiösen Spondylitis handelt es sich in der Regel um eine Osteomyelitis von 2benachbarten Wirbelkörpern unter Beteiligung der Zwischenwirbelscheibe (Spondylodiszitis). Am häufigsten ist die Lendenwirbelsäule betroffen, gefolgt von der Brustwirbelsäule. Die Symptome der infektiösen Spondylitis sind unspezifisch, was nicht selten zu einer Verzögerung von einigen Wochen bis zur Diagnosestellung führt. Die infektiöse Spondylitis kann durch eine Vielzahl von Erregern bedingt sein, die überwiegend auf hämatogenem Weg die Wirbelsäule erreichen. Der häufigste Erreger ist Staphyloccocus aureus. Die Spondylitis ist zudem die häufigste skelettale Manifestation der Tuberkulose. Wie bei anderen Formen der Osteomyelitis ist die Kenntnis des Erregers für die Wahl einer adäquaten Therapie entscheidend, weshalb eine mikrobiologische Diagnose auf jeden Fall angestrebt werden sollte. Die Mehrheit der Fälle kann konservativ mit antibiotischer Therapie geheilt werde

Unambiguous state discrimination in quantum cryptography with weak coherent states

The use of linearly independent signal states in realistic implementations of quantum key distribution (QKD) enables an eavesdropper to perform unambiguous state discrimination. We explore quantitatively the limits for secure QKD imposed by this fact taking into account that the receiver can monitor to some extend the photon number statistics of the signals even with todays standard detection schemes. We compare our attack to the beamsplitting attack and show that security against beamsplitting attack does not necessarily imply security against the attack considered here.Comment: 10 pages, 6 figures, updated version with added discussion of beamsplitting attac

An Adaptive Threshold in Mammalian Neocortical Evolution

Expansion of the neocortex is a hallmark of human evolution. However, it remains an open question what adaptive mechanisms facilitated its expansion. Here we show, using gyrencephaly index (GI) and other physiological and life-history data for 102 mammalian species, that gyrencephaly is an ancestral mammalian trait. We provide evidence that the evolution of a highly folded neocortex, as observed in humans, requires the traversal of a threshold of 10^9 neurons, and that species above and below the threshold exhibit a bimodal distribution of physiological and life-history traits, establishing two phenotypic groups. We identify, using discrete mathematical models, proliferative divisions of progenitors in the basal compartment of the developing neocortex as evolutionarily necessary and sufficient for generating a fourteen-fold increase in daily prenatal neuron production and thus traversal of the neuronal threshold. We demonstrate that length of neurogenic period, rather than any novel progenitor-type, is sufficient to distinguish cortical neuron number between species within the same phenotypic group.Comment: Currently under review; 38 pages, 5 Figures, 13 Supplementary Figures, 2 Table

The potential negative impact of antibiotic pack on antibiotic stewardship in primary care in Switzerland: a modelling study.

BACKGROUND: In Switzerland, oral antibiotics are dispensed in packs rather than by exact pill-count. We investigated whether available packs support compliance with recommended primary care treatment regimens for common infections in children and adults. METHODS: Hospital-based guidelines for oral community -based treatment of acute otitis media, sinusitis, tonsillopharyngitis, community-acquired pneumonia and afebrile urinary tract infection were identified in 2017 in an iterative process by contacting hospital pharmacists and infectious diseases specialists. Furthermore, newly available national guidelines published in 2019 were reviewed. Available pack sizes for recommended solid, dispersible and liquid antibiotic formulations were retrieved from the Swiss pharmaceutical register and compared with recommended regimens to determine optimal (no leftovers) and adequate (optimal +/- one dose) matches. RESULTS: A large variety of recommended regimens were identified. For adults, optimal and adequate packs were available for 25/70 (36%) and 8/70 (11%) regimens, respectively. Pack-regimen matching was better for WHO Watch (optimal: 15/24, 63%) than Access antibiotics (optimal: 7/39, 18%). For the four paediatric weight-examples and 42 regimens involving child-appropriate formulations, optimal and adequate packs were available for only 14/168 (8%) and 27/168 (16%), respectively. Matching was better for older children with higher body and for longer treatment courses > 7 days. CONCLUSIONS: Fixed antibiotic packs often do not match recommended treatment regimens, especially for children, potentially resulting in longer than necessary treatments and leftover doses in the community. As part of national stewardship, a move to an exact pill-count system, including for child-appropriate solid formulations, should be considered