The semantics of untrustworthiness

We offer a formal treatment of the semantics of both complete and incomplete mistrustful or distrustful information transmissions. The semantics of such relations is analysed in view of rules that define the behaviour of a receiving agent. We justify this approach in view of human agent communications and secure system design. We further specify some properties of such relations

Noise and Bell's inequality

From the beginning of quantum mechanics, there has been a discussion about the concept of reality, as exemplified by the EPR paradox. To many, the idea of the paradox and the possibility of local hidden variables was dismissed by the Bell inequality. Yet, there remains considerable evidence that this inequality can be violated even by classical systems, so that experiments showing quantum behavior and the violation of the inequality must be questioned. Here, we demonstrate that classical optical polarization experiments based upon noise in the system can be shown to violate the Bell inequality.Comment: Fluctuation and Noise Letters, in pres

Moduli Stacks of Vector Bundles and Frobenius Morphisms

We describe the action of the different Frobenius morphisms on the cohomology ring of the moduli stack of algebraic vector bundles of fixed rank and determinant on an algebraic curve over a finite field in characteristic p and analyse special situations like vector bundles on the projective line and relations with infinite Grassmannians.Comment: 19 page

Bovine brucellosis: A study of the serological aspects of the disease

A study of bovine brucellosis was carried out on a herd of mixed vaccination history with a view to evaluating the various methods of diagnosis used under field conditions in Great Britain. It was shown that the milk ring and whey agglutination tests were largely negative in calfhood-vaccinated brucella-free animals (85.1% and 96.1% respectively). In animals vaccinated as adults or repeat vaccinated, the milk ring test appears to be valueless as an indicator of field infection because of the very high percentage of falsely positive results (47.7%). The whey agglutination test was shown to be as valuable in these cattle as in calfhood-vaccinated cows, provided that the level of significance of whey agglutinins was taken as 1:10. The whey agglutinin titres appear to be influenced by the stage of lactations and there is a rise in the percentage of positives with advancing gestation. It is suggested that the milk ring and whey agglutination tests on them are of little value in the detection of infected animals since these are detected more readily by repeat serum agglutination test alone, but they are valuable as moderators in cases where the serum agglutination test gave doubtful results. The results of the vaginal mucus agglutination test indicate that tis value is very similar to that of the whey agglutination test in that it does not help significantly in the detection of infected animals but does serve to indicate absence of brucella infection in animals giving doubtful serum agglutinin titres. Over-age vaccination of cattle with Br.abortus S19 diminishes the value of the serum agglutination test to a considerable degree. The vaccinal serum agglutinin titre persists much longer in adult-vaccinated animals than in calfhood-vaccinated stock. There is a marked tendency for the serum titres of adult and also of calfhood-vaccinated animals, born and vaccinated in an infected environment, to show fluctuation of serum titres. One result of this fluctuation is that, on occasions, non-infected animals may show higher titres than animals known to be infected with Br.abortus. It is suggested that the too rigid application of the accepted criteria to the interpretation of serum agglutinin titres of adult-vaccinated cows may cause the disposal of many cows which may never constitute any danger for the rest of the herd. The examination of milk and vaginal mucus samples may be of real value in this situation. The results of cultural and biological examination of milk, vaginal mucus, post-partum and autopsy specimens indicated that the time and expense involved in these tests, purely for the diagnosis of brucella infection, is not proportionate to their value. However, where maximum safety is required their use may be justified. (Abstract shortened by ProQuest.)

Imaging Spin Reorientation Transitions in Consecutive Atomic Co layers

By means of spin-polarized low-energy electron microscopy (SPLEEM) we show that the magnetic easy-axis of one to three atomic-layer thick cobalt films on ruthenium crystals changes its orientation twice during deposition: one-monolayer and three-monolayer thick films are magnetized in-plane, while two-monolayer films are magnetized out-of-plane, with a Curie temperature well above room temperature. Fully-relativistic calculations based on the Screened Korringa-Kohn-Rostoker (SKKR) method demonstrate that only for two-monolayer cobalt films the interplay between strain, surface and interface effects leads to perpendicular magnetization.Comment: 5 pages, 4 figures. Presented at the 2005 ECOSS conference in Berlin, and at the 2005 Fall meeting of the MRS. Accepted for publication at Phys. Rev. Lett., after minor change