Erfgoed in interessante tijden

In de jaren negentig van de vorige eeuw vonden twee ontwikkelingen plaats die het denken over de relatie tussen erfgoed en ruimte hebben gestimuleerd. De eerste was een hernieuwde groei van de belangstelling voor historische landschappen. Die belangstelling had al een paar keer eerder, in de jaren twintig/dertig, in de jaren zeventig en in de jaren negentig van de vorige eeuw, perioden van groei meegemaakt. In de jaren twintig en dertig werd het landschap ‘ontdekt’ en werden de eerste beschermingsmaatregelen getroffen.2 In de jaren zeventig maakte de belangstelling voor het landschap deel uit van een veel bredere bewustwording van de bedreigingen waaraan de omgeving blootstond; het waren ook de jaren van het opkomende milieubesef. In deze jaren zien we bijvoorbeeld de proef om Nationale Landschapsparken te stichten – nog altijd de enige serieuze poging om in Nederland historische landschappen te beschermen – en de Relatienota.3 De Nationale Landschappen hebben het, zoals bekend, niet gehaald

Unconditional Security of Three State Quantum Key Distribution Protocols

Quantum key distribution (QKD) protocols are cryptographic techniques with security based only on the laws of quantum mechanics. Two prominent QKD schemes are the BB84 and B92 protocols that use four and two quantum states, respectively. In 2000, Phoenix et al. proposed a new family of three state protocols that offers advantages over the previous schemes. Until now, an error rate threshold for security of the symmetric trine spherical code QKD protocol has only been shown for the trivial intercept/resend eavesdropping strategy. In this paper, we prove the unconditional security of the trine spherical code QKD protocol, demonstrating its security up to a bit error rate of 9.81%. We also discuss on how this proof applies to a version of the trine spherical code QKD protocol where the error rate is evaluated from the number of inconclusive events.Comment: 4 pages, published versio

Dairy farmers can change: results of a five-year national mastitis control program in The Netherlands

Over the years, much effort has been put into mastitis control programs. To further improve such programs, we need to understand farmers’ knowledge, attitude and behavior regarding udder health, and the way this can be influenced by mastitis control programs. This study aimed to explore the effect of a Dutch national mastitis control program on farmers’ knowledge, attitude and behavior regarding mastitis. In this study, 204 randomly selected dairy farmers completed a survey on attitude, knowledge and behavior regarding mastitis before the start of the national mastitis control program (2004) and in the final year of the program (2009). Statistical analyses show that, compared to 2004, the attitude, knowledge and behavior of the participating farmers changed significantly. Farmers’ satisfaction level and problem level of BMSCC changed; farmers were satisfied with on average 156,000 cells/ml in 2004 compared to 150,000 cells/ml in 2009, and perceived a problem at 285,000 cells/ml in 2004 compared to 271,000 cells/ml in 2009. More farmers perceived that they had sufficient knowledge about the control of mastitis (34% in 2004 vs. 53% in 2009), and they focused more often on udder health characteristics when selecting bulls (46% vs. 61%). Specific mastitis control measures have increased significantly during the program. The use of milking gloves increased from 15% to 46%, the use of a standardized mastitis treatment protocol increased from 7% to 34% and cubicles are cleaned more often (2.28 vs. 2.51 times/day)

Generalized Entropies

We study an entropy measure for quantum systems that generalizes the von Neumann entropy as well as its classical counterpart, the Gibbs or Shannon entropy. The entropy measure is based on hypothesis testing and has an elegant formulation as a semidefinite program, a type of convex optimization. After establishing a few basic properties, we prove upper and lower bounds in terms of the smooth entropies, a family of entropy measures that is used to characterize a wide range of operational quantities. From the formulation as a semidefinite program, we also prove a result on decomposition of hypothesis tests, which leads to a chain rule for the entropy.Comment: 21 page

Spherical Code Key Distribution Protocols for Qubits

Recently spherical codes were introduced as potentially more capable ensembles for quantum key distribution. Here we develop specific key creation protocols for the two qubit-based spherical codes, the trine and tetrahedron, and analyze them in the context of a suitably-tailored intercept/resend attack, both in standard form, and a ``gentler'' version whose back-action on the quantum state is weaker. When compared to the standard unbiased basis protocols, BB84 and six-state, two distinct advantages are found. First, they offer improved tolerance of eavesdropping, the trine besting its counterpart BB84 and the tetrahedron the six-state protocol. Second, the key error rate may be computed from the sift rate of the protocol itself, removing the need to sacrifice key bits for this purpose. This simplifies the protocol and improves the overall key rate.Comment: 4 pages revtex, 2 figures; clarified security analysis. Final version for publicatio

Історія Гамаліївського Харлампієва монастиря

Стаття присвячена історії Гамаліївського Харлампієвого монастиря та ансамблю його пам’яток.Статья посвящена истории Гамалеевского Харлампиева монастыря и ансамблю его памятников.I his article deals with a short history of Gamaliivskyi Kharlampievyi monastery and a band of its sights since its foundation up to hour

Minimal Informationally Complete Measurements for Pure States

We consider measurements, described by a positive-operator-valued measure (POVM), whose outcome probabilities determine an arbitrary pure state of a D-dimensional quantum system. We call such a measurement a pure-state informationally complete (PSI-complete) POVM. We show that a measurement with 2D-1 outcomes cannot be PSI-complete, and then we construct a POVM with 2D outcomes that suffices, thus showing that a minimal PSI-complete POVM has 2D outcomes. We also consider PSI-complete POVMs that have only rank-one POVM elements and construct an example with 3D-2 outcomes, which is a generalization of the tetrahedral measurement for a qubit. The question of the minimal number of elements in a rank-one PSI-complete POVM is left open.Comment: 2 figures, submitted for the Asher Peres festschrif