The effectiveness of quantum operations for eavesdropping on sealed messages

A quantum protocol is described which enables a user to send sealed messages and that allows for the detection of active eavesdroppers. We examine a class of eavesdropping strategies, those that make use of quantum operations, and we determine the information gain versus disturbance caused by these strategies. We demonstrate this tradeoff with an example and we compare this protocol to quantum key distribution, quantum direct communication, and quantum seal protocols.Comment: 10 pages, 2 figures. Third Feynman Festival, 25 -- 29 August 2006, University of Maryland, College Park, Maryland, U.S.

Fidelity of Quantum Interferometers

For a generic interferometer, the conditional probability density distribution, $p(\phi|m)$, for the phase $\phi$ given measurement outcome $m$, will generally have multiple peaks. Therefore, the phase sensitivity of an interferometer cannot be adequately characterized by the standard deviation, such as $\Delta\phi\sim 1/\sqrt{N}$ (the standard limit), or $\Delta\phi\sim 1/N$ (the Heisenberg limit). We propose an alternative measure of phase sensitivity--the fidelity of an interferometer--defined as the Shannon mutual information between the phase shift $\phi$\ and the measurement outcomes $m$. As an example application of interferometer fidelity, we consider a generic optical Mach-Zehnder interferometer, used as a sensor of a classical field. We find the surprising result that an entangled {\it N00N} state input leads to a lower fidelity than a Fock state input, for the same photon number.Comment: 4 pages, 3 figure

Screening for potential effects of endocrine-disrupting chemicals in peri-urban creeks and rivers in Melbourne, Australia using mosquitofish and recombinant receptor-reporter gene assays

Sexually mature male mosquitofish (Gambusia holbrooki) were collected from various sites around Melbourne in 2009 to evaluate the performance of gonopodial indices as a biomarker for endocrine disruption in Melbourne's waterways. The mosquitofish indices assessed were body length (BL), gonopodial length (GL)/BL ratio, ray 4:6 ratio and the absence or presence of hooks and serrae, and these varied between sites. The study was complemented by measurements of estrogenic, retinoid, thyroid and aryl hydrocarbon (AhR) receptor activities of the water. Male mosquitofish were 16.3-21.5 mm in length, and although there was a statistically significant positive relationship showing that bigger fish had longer gonopodia than small fish (r2 = 0.52, p < 0.001), there were few significant differences in GL/BL ratio of fish between sites. Measured estrogenic activity was mostly in the range 0.1-1.7 ng/L EEQ, with one site having much higher levels (similar to 12 ng/L EEQ). Aryl hydrocarbon (AhR) receptor activity was observed in all water samples (7-180 ng/L beta NF EQ), although there was no consistent pattern in the level of AhR activity observed, i.e., 'clean' sites were as likely to return a high AhR activity response as urban or wastewater treatment plant (WWTP)-impacted sites. There was no correlation between measurements of receptor actvity and gonopodial length (GL):BL ratio and BL. We conclude that the mosquitofish gonopodia only fulfills part of the criteria for biomarker selection for screening. The mosquitofish indices assessed were cheap and easy-to-perform procedures; however, there is no baseline data from the selected sites to evaluate whether differences in the morpholical indices observed at a site were a result of natural selection in the population or due to estrogenic exposure

Pre-service Teacher Beliefs on the Antecedents to Bullying: A Concept Mapping Study

In this study, researchers gathered Canadian pre-service teachers’ beliefs on the antecedents to bullying. Concept mapping (Kane & Trochim, 2007) was used to analyze the data. This study’s findings identified pre-service teachers to have accurate beliefs, inaccurate beliefs, and a lack of knowledge about the antecedents to bullying. Concept maps and accompanying factor-rating tables indicate that participants believe antecedents to bullying include family factors, abuse, instability and socio-economic factors, school and academic factors, interpersonal factors, and personal factors. Results may inform pre-service teachers’ knowledge, and indicate what information pre-service teachers need to be taught

Of combined electric arc coatings

The paper considers possibilities to increase the wear resistance for parts machines and mechanisms using combined electric arc coatings thanks to nitriding the coatings deposited. The possibility of controlling the properties of surfaces owing to choice with required characteristics electric arc coatings is shown. The influence of spray factors such as the flow rate and pressure of working gases, composition of combustion mixture, spraying distance, dispersion of the spray, properties of wire material, etc. on the properties of the coatings obtained has been investigated. The paper considers the use of pulse ion nitriding of arc-spray EAS (eelectric arc spraying) coatings from wire materials as one of the efficient ways to increase their performance characteristics.=В работе предложено повышать износостойкость деталей машин и механизмоа комбинированными ЭДН-покрытиями за счет азотирования напыленных покрытий. В работе исследование влияния факторов процесса элпектродугового напыления: расхода и давления рабочих газов, состава горючей смеси, дистанции напыления, дисперсности распыления, свойств материала проволоки и др. на свойства ЭДН-покрытий. В работе рассмотрен один из способов повышения эксплуатационных характеристик ЭДН-покрытий из проволочных материалов посредством использования импульсного ионного азотирования. В работе предложено повышать износостойкостьь и срок службы деталей машин и механизмоа при их упрочнении и реновации комбинированными ЭДН-покрытиями с высокой плотностью, прочностью сцепления и микротвердостью за счет управления параметрами электродугового напыления и процесса азотирования напыленных покрытий. В работе рассмотрена возможность обеспечивать необходимые свойства поверхностей с целью повышения ресурса деталей машин путем регулирования факторами ЭДН. В частности, регулируя скорость и температуру струи транспортирующего газа и частиц можно уменьшить диаметр капель, повысить плотность и снизить окисляемость покрытий. В работе исследование влияния факторов процесса напыления: расхода и давления рабочих газов, состава горючей смеси, дистанции напыления, дисперсности распыления, свойств материала проволоки и др. на свойства ЭДН-покрытий. В работе рассмотрен один из способов повышения эксплуатационных характеристик ЭДН-покрытий из проволочных материалов посредством использования ионного азотирования