Quantum Non-Demolition Test of Bipartite Complementarity

We present a quantum circuit that implements a non-demolition measurement of complementary single- and bi-partite properties of a two-qubit system: entanglement and single-partite visibility and predictability. The system must be in a pure state with real coefficients in the computational basis, which allows a direct operational interpretation of those properties. The circuit can be realized in many systems of interest to quantum information.Comment: 4 pages, 2 figure

Experimental Observation of Environment-induced Sudden Death of Entanglement

We demonstrate the difference between local, single-particle dynamics and global dynamics of entangled quantum systems coupled to independent environments. Using an all-optical experimental setup, we show that, while the environment-induced decay of each system is asymptotic, quantum entanglement may suddenly disappear. This "sudden death" constitutes yet another distinct and counter-intuitive trait of entanglement.Comment: 4 pages, 4 figure

A model for structural defects in nanomagnets

A model for describing structural pointlike defects in nanoscaled ferromagnetic materials is presented. Its details are explicitly developed whenever interacting with a vortex-like state comprised in a thin nanodisk. Among others, our model yields results for the vortex equilibrium position under the influence of several defects along with an external magnetic field in good qualitative agreement with experiments. We also discuss how such defects may affect the vortex motion, like its gyrotropic oscillation and dynamical polarization reversal.Comment: 8 pages, resubmitted to Journal of Applied Physic

Impact of biofilms in simulated drinking water and urban heat supply systems

Biofouling and biocorrosion were studied in drinking water and heating water systems by forming biofilms on steel and on polymethylmetacrylate. In the drinking water system, biofilm development was more significant on corroded surfaces, suggesting that in these conditions they were largely protected from disinfection, probably because of sheltering and chlorine demand by corrosion products. In the urban heat supply system, results suggest a higher biofilm activity at lower pH. Sulphate-reducing bacteria were detected in the urban heating biofilms, but little corrosion was observed on steel coupons. Results indicate that surface and bulk medium properties, as well as bacterial diversity are determinant parameters when studying biofouling and biocorrosion.Cirius – Danish Centre for International Cooperation and Mobility in Education and Trainin

The influence of surface material on the development of Desulfovibrio desulfuricans biofilms

Sulphate reducing bacteria have an important role in the sulphur cycle, and therefore in wastewater treatment systems. They are able to form biofilms on metallic surfaces, leading to fouling and corrosion problems. Additionally, hydrogen sulphide that is a product of their metabolism can cause serious health risks. In this study, sulphate reducing bacteria (SRB) biofilms were developed on stainless steel 304 and on polycarbonate in order to evaluate surface effect on biofilm formation. Results showed that the biofilm formed on stainless steel presented higher metabolic activity, confirmed by lactate and sulfate removals. Metal elements present in stainless steel may affect SRB activity. This can be the case of nickel that represents around 8% of stainless steel 304. Studies performed with suspended cultures of Desulfovibrio desulfuricans also showed that the presence of nickel in the media had a positive impact on bacterial activity

The influence of nickel on the adhesion ability of Desulfovibrio desulfuricans

The build-up of biofilms on metals surfaces may lead to severe corrosion, especially in the presence of sulphate-reducing bacteria (SRB). To prevent the deterioration of material caused by biofilms it is necessary to understand the processes governing biofilm development including mechanisms of cell adhesion. Additionally, corrosion of metallic surfaces due to bacteria may lead to the dissolution of metallic elements that may further affect adhesion and biofilm development. A study was carried out to evaluate how the presence of nickel in the substrata affects the adhesion ability of Desulfovibrio desulfuricans. The substrata tested were stainless steel 304 (SS), metallic nickel (Ni) and polymethylmetacrylate (PMMA), a non-metallic material used as control. The influence of nickel on SRB growth and its relation to adhesion was also checked. A statistically significant difference in the number of adhered cells to the materials tested was detected, with higher bacterial number on nickel, followed by SS and finally by PMMA. The higher number of SRB adhered to steel compared with PMMA may be explained by differences in hydrophobicity, in roughness and in the electron-acceptor character of the substrata. Additionally, bacterial growth was found to be positively affected by the presence of nickel as revealed by a significant increase in the specific growth rate of SRB in the presence of increased nickel concentrations.Programme Praxis XXI

The effect of dissolved stainless steel alloy elements on the activity and growth of SRB

Sulphate reducing bacteria have an important role in the sulphur cycle, and therefore in wastewater treatment systems. They are able to form biofilms on metallic surfaces, leading to fouling and corrosion problems. These bacteria are among the micro-organisms most frequently implicated in microbial corrosion of iron and ferrous alloys. Alloying elements added to steels for the improvement of their corrosion resistance such as molybdenum and nickel can be dissolved in bulk liquid during the corrosion processes and therefore available to the micro-organisms. That may affect bacterial metabolism and adhesion. In this study, suspended cultures of sulphate reducing bacteria (SRB) were subjected to several nickel concentrations in order to evaluate the effect of the dissolved metal on bacterial metabolism. Simultaneously, SRB biofilms were developed on stainless steel 304 and on polymethylmethacrylate (PMMA) in order to study surface effect on biofilm formation. Results showed that nickel (Ni) in all tested concentrations between 0.006 and 5 mg/L had a positive effect on the growth of Desuljovibrio desulfuricans. Additionally, biofilms formed on stainless steel presented higher metabolic activity, confirmed by sulphate removal and acetate concentration in the effluent stream. Metal elements present in stainless steel may affect SRB activity. This can be the case of nickel that represents around 8% of stainless steel 304 and that had a positive impact on suspended SRB cultures, under the tested concentrations

Prediction of genetic potential of common bean segregant populations for slow seed-coat darkening.

The objective of this study was to predict the genetic potential of common bean segregant populations for slow seed-coat darkening