Callitriche cophocarpa — a new rich source of active phenolic compounds

This study was focused on the analysis of the contents (by HPLC-DAD) and antioxidant activity of phenolic compounds of aquatic higher plant Callitriche cophocarpa. The novelty of the work was: 1) the study of the species which is almost unknown in the context of investigations of bio-active compounds and, 2) the application of a unique L-band electron resonance spectroscopy (L-band EPR) to measure antioxidant activity of samples. The results were compared with those obtained for microalgae Chlorella and Spirulina which are widely distributed as the diet supplements. The obtained results are very promising with respect to the freeze-dried material of Callitriche, which revealed both high level of phenolic compounds (33 mg g^?1 dry weight) and antioxidant activity (0.14 g of reduced DPPH· g^?1 dry weight). An isoform of sinapic acid appeared to be the main fraction in this sample. The average content of the total phenolic compounds in Callitriche freeze-dried samples was ca. 43 or 25 times higher than in the case of the Chlorella or Spirulina samples, respectively. These samples showed also 16 times lower scavenging activity in relation to freeze-dried Callitriche material.      

Bonus or flat wage? An experiment into the principal-agent problem

We conduct a simple principal-agent experiment in order to find the effects of information asymmetry on compensation. Our aim is the analysis of the appropriate compensation and its impact on employee’s effort. Furthermore we want to compare the offered compensation and the supplied effort in the version without communication and we want to know whether the experimental observations are consistent with the theoretical considerations.The experimenters found out that compensations observed during the experiment were different from those suggested by the theory and although they were theoretically not enough to induce high effort, we could observe high performance supplied by the agents.     

A Quantum Version of Sanov's Theorem

We present a quantum version of Sanov's theorem focussing on a hypothesis testing aspect of the theorem: There exists a sequence of typical subspaces for a given set Ψ of stationary quantum product states asymptotically separating them from another fixed stationary product state. Analogously to the classical case, the separating rate on a logarithmic scale is equal to the infimum of the quantum relative entropy with respect to the quantum reference state over the set Ψ. While in the classical case the separating subsets can be chosen universally, in the sense that they depend only on the chosen set of i.i.d. processes, in the quantum case the choice of the separating subspaces depends additionally on the reference state.     

The effective sky temperature: an enigmatic concept

To properly simulate the condensation process and design a water recovery system from condensation of atmospheric water vapour on a surface maintained below the dew point by radiative heat loss from the surface to night sky, an accurate estimation of the effective sky temperature is required. To estimate the effective night sky temperature, an experimental system consisting of a series of metal plates embedded on a heat transfer panel, a weather station and a control system was used. The results obtained from theoretical analyses and preliminary experiments are presented and discussed. A special emphasis is given to a mathematical solution of the system of equations that need to be solved to obtain the effective sky temperature. It is shown that although the system of equations works well for the direct heat transfer problem, there is a serious difficulty to solve the inverse heat transfer problem to retrieve the desired parameters.     

Reporting behavior: a literature review of experimental studies

Central European Journal of Operations Research - The literature review focuses on reporting behavior under information (a)symmetry both from the perspective of behavioral management accounting and...     

The influence of face-to-face communication: a principal-agent experiment

The principal-agent problem is an interesting problem involved in many everyday relationships, such as the one between company owners and their delegates. Our experiment simulates such a relationship, whereby the task of participating pairs is to negotiate labor contracts. Our aim is to find the effects of face-to-face communication and negotiation on contract framing. We argue that including pre-play communication into the principal-agent problem leads to a significant improvement of agent’s effort and results in changes of the compensation scheme. We show that incentives are not the only possibility to induce high effort. We use content analysis of the video-taped negotiations to find some characteristics of the communication process.     

Typical Support and Sanov Large Deviations of Correlated States

Discrete stationary classical processes as well as quantum lattice states are asymptotically confined to their respective typical support, the exponential growth rate of which is given by the (maximal ergodic) entropy. In the iid case the distinguishability of typical supports can be asymptotically specified by means of the relative entropy, according to Sanov’s theorem. We give an extension to the correlated case, referring to the newly introduced class of HP-states.     

XPS characterization of YAlO3:Co single crystals

YAlO₃:Co (YAP:Co) single crystals have been obtained by the Czochralski method. The XPS spectra of YAP:Co annealed in reducing atmospheres: H₂, vacuum and vacuum plus H₂ are presented and discussed. As confirmed by magnetic measurements and the electron spectroscopy XPS the dopant concentration of Co is lower than a nominal one. The annealing processes removed colour centers due to relocation and some reduction of oxygen ions in the structure. The increased unit volume during the long annealing process may be caused by the change in some Co³⁺ ions into Co²⁺ ions. This explains the occurrence of the violet colour of the longtime annealed samples. The chemical shift analysis shows more ionic bond of Y–O than Al–O. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)