Thermal and mechanical properties of a DNA model with solvation barrier

We study the thermal and mechanical behavior of DNA denaturation in the frame of the mesoscopic Peyrard- Bishop-Dauxois model with the inclusion of solvent interaction. By analyzing the melting transition of a homogeneous A-T sequence, we are able to set suitable values of the parameters of the model and study the formation and stability of bubbles in the system. Then, we focus on the case of the P5 promoter sequence and use the Principal Component Analysis of the trajectories to extract the main information on the dynamical behavior of the system. We find that this analysis method gives an excellent agreement with previous biological results.Comment: Physical Review E (in press

Heating without heat: thermodynamics of passive energy filters between finite systems

Passive filters allowing the exchange of particles in a narrow band of energy are currently used in micro-refrigerators and energy transducers. In this letter, we analyze their thermal properties using linear irreversible thermodynamics and kinetic theory, and discuss a striking phenomenon: the possibility of increasing or decreasing simultaneously the temperatures of two systems without any supply of energy. This occurs when the filter induces a flow of particles whose energy is between the average energies of the two systems. Here we show that this selective transfer of particles does not need the action of any sort of Maxwell demon and can be carried out by passive filters without compromising the second law of thermodynamics. The phenomenon allows us to design cycles between two reservoirs at temperatures $T_1<T_2$ that are able to reach temperatures below $T_1$ or above $T_2$.Comment: 5 pages, 3 figure

A comparative analysis between two statistical deviation–based consensus measures in group decision making problems

The mean absolute deviation and the standard deviation, two statistical measures commonly used in quantifying variability, may become an interesting tool when defining consensus measures. Two consensus indexes which obtain the level of consensus in some problems of Group Decision Making are introduced in this paper by expanding the aforementioned statistical concepts. A comparative analysis reveals that the levels of consensus derived from these indexes are close to those obtained employing distance functions when a fuzzy preference relations frame is considered, so they turn out to be a useful tool in this context. In addition, these indexes are different from each other and with the distance functions considered. Thus, they are applicable tools in the calculation of consensus in our context and are different from those commonly used

Tender offers in South America: Are abnormal returns really high?

Different studies in developed capitalmarkets have found positive abnormalreturns of at least 15% during theannouncement date of a tender offer.Although there are almost no studiesfor South American stock markets,some studies reported positive abnormalreturns, ranging from 25% to50%, related to the announcement ofthe fi rst tender offer. In this study oneargues that estimated positive abnormalreturns in emerging markets arehigh because studies have assumed acompletely segmented capital marketby applying the market model with alocal stock market index. By allowingfor partial integration among fiveSouth American emerging markets,one shows that there are in factpositive abnormal returns previously,during, and after the announcementdate of the fi rst tender offer. However,the positive abnormal returnassociated to the announcementdate is in the order of 8%. A slightlyhigher abnormal return is obtainedusing a market model that accountsfor partial integration and downsiderisk. These results prompt towardsa lower positive abnormal return inthe sample of South American fi rmsstudied.Tender offer, abnormal return, emergingmarket.