Light Collimation and Focussing by a Thin Flat Metallic Slab

We present experimental and theoretical work showing that a flat metallic slab can collimate and focus light impinging on the slab from a punctual source. The effect is optimised when the radiation is around the bulk, not at the surface, plasma frequency. And the smaller the imaginary part of the permittivity is, the better the collimation. Experiments for Ag in the visible as well as calculations are presented. We also discuss the interesting case of the Aluminium whose imaginary part of the permittivity is very small at the plasma frequency in UV radiation. Generalization to other materials and radiations are also discussed.Comment: 6 pages, 3 figures. To be published on Optics Lette

Episodic liquidity crises: cooperative and predatory trading,”

ABSTRACT We describe how episodic illiquidity arises from a breakdown in cooperation between market participants. We first solve a one-period trading game in continuous-time, using an asset pricing equation that accounts for the price impact of trading. Then, in a multi-period framework, we describe an equilibrium in which traders cooperate most of the time through repeated interaction and provide 'apparent liquidity' to each other. Cooperation breaks down when the stakes are high, leading to predatory trading and episodic illiquidity. Equilibrium strategies involving cooperation across markets lead to less frequent episodic illiquidity, but cause contagion when cooperation breaks down. * Bruce Ian Carlin, Miguel Sousa Lobo, and S. Viswanathan are from the Fuqua School of Business at Duke University. The authors would like to than

Non-Standard Errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants

UV-ABSORPTION MECHANISMS OF Ni 2+ -BINDING BOVINE SERUM ALBUMIN

Interactions proteins-metalic ions are a major concern in various emerging fields like bionanotchnology and material sciences.Nickel is known to be an essential element for the living organisms those deficiences cause allergic reactions, dermatitis, asthma, and also can induce carcinogenesis. Although it is known that binds to albumin, his physiological role is not complete established. Certainly, this role must be connected to the intimate physical and electrochemical features of the binding process. We present any new results concerning the binding process of Ni 2+ on BSA, according to the UV absorbance spectrum structure of th

Comparative study on decontamination treatment of paper-based materials in corona discharge and HF cold plasma

Documents decontamination using dry methods, less invasive than the wet ones implying toxic nocuous substances for cellulose-based materials, has been the object of numerous studies. In recent years mixed researchers teams have been studying the possibility of one-step document decontamination performed by a dry treatment, the risks of repeated wet manipulation thus being reduced. Among physical methods appropriate to this end, high-frequency cold plasma and corona effect can be mentioned. Our studies were carried out on samples taken from ancient books with no cultural heritage value. The decontamination efficiency and the impact on paper of the two types of treatments were determined by: microbiological analysis, scanning electron microscopy, FTIR, chromatic alterations and gloss determination. The above-mentioned procedures eliminate the use of chemical conservation substances, nocuous for the paper support. At the same time the health risk for conservators, restorers, archivists or archive’s users is removed

Comparative study on decontamination treatment of paper-based materials in corona discharge and HF cold plasma

Documents decontamination using dry methods, less invasive than the wet ones implying toxic nocuous substances for cellulose-based materials, has been the object of numerous studies. In recent years mixed researchers teams have been studying the possibility of one-step document decontamination performed by a dry treatment, the risks of repeated wet manipulation thus being reduced. Among physical methods appropriate to this end, high-frequency cold plasma and corona effect can be mentioned. Our studies were carried out on samples taken from ancient books with no cultural heritage value. The decontamination efficiency and the impact on paper of the two types of treatments were determined by: microbiological analysis, scanning electron microscopy, FTIR, chromatic alterations and gloss determination. The above-mentioned procedures eliminate the use of chemical conservation substances, nocuous for the paper support. At the same time the health risk for conservators, restorers, archivists or archive’s users is removed