Equilibrium states of a test particle coupled to finite size heat baths

We report on numerical simulations of the dynamics of a test particle coupled to competing Boltzmann heat baths of finite size. After discussing some features of the single bath case, we show that the presence of two heat baths further constraints the conditions necessary for the test particle to thermalize with the heat baths. We find that thermalization is a spectral property in which the oscillators of the bath with frequencies in the range of the test particle characteristic frequency determine its degree of thermalization. We also find an unexpected frequency shift of the test particle response with respect to the spectra of the two heat baths. Finally, we discuss implications of our results for the study of high-frequency nanomechanical resonators through cold damping cooling techniques, and for engineering reservoirs capable of mitigating the back-action on a mechanical system.Comment: Strongly related to arXiV:0810.3251 (appeared in European Physical Journal B 61, 271 (2008

Soil carbon sequestration rates under Mediterranean woody crops using recommended management practices : A meta-analysis

This work was supported by the projects: CARBOLIVAR (P11-RNM-7186) funded by Consejería de Innovación, Ciencia y Empresa of Junta de Andalucía and GEISpain project (CGL2014‐52838‐C2‐1‐R) funded by Ministerio de Economía y Competitividad, both including European Union ERDF funds. This work was also supported by the FPU 2012 grant program of the Ministerio de Educación, Cultura y Deporte of Spain. Dr. Roberto Garcia-Ruiz and Eduardo Aguilera gratefully acknowledge support by the Sustainable Farm Systems project (SSHRC 895-2011-1020) funded by the Canadian Social Sciences and Humanities Research Council.Peer reviewedPostprin

A new table of permutation codes

Permutation codes (or permutation arrays) have received considerable interest in recent years, partly motivated by a potential application to powerline communication. Powerline communication is the transmission of data over the electricity distribution system. This environment is rather hostile to communication and the requirements are such that permutation codes may be suitable. The problem addressed in this study is the construction of permutation codes with a specified length and minimum Hamming distance, and with as many codewords (permutations) as possible. A number of techniques are used including construction by automorphism group and several variations of clique search based on vertex degrees. Many significant improvements are obtained to the size of the best known code

La physique naïve: un essai d'ontologie

The project of a naive physics has been the subject of attention in recent years above all in the artificial intelligence field, in connection with work on common-sense reasoning, perceptual representation and robotics. The idea of a theory of the common-sense world is however much older than this, having its roots not least in the work of phenomenologists and Gestalt psychologists such as Kohler, Husserl, Schapp and Gibson. This paper seeks to show how contemporary naive physicists can profit from a knowledge of these historical roots of their discipline, which are shown to imply above all a critique of the set-theory-based models of reality typically presupposed by contemporary work in common-sense ontology

On the status of Dusky-legged Guan Penelope obscura Temminck, 1815 (Aves: Cracidae) in Paraguay

Despite repeated references to the species in Paraguay, the status of the Dusky-legged Guan Penelope obscura in the country has been the subject of much debate. In an attempt to clarify the available data, a thorough review of literature records is provided and details of new and previously unpublished records that confirm that the nominate subspecies is present in Paraguay are given. With the species limits in the obscura complex poorly defined, we provide a brief discussion of the potential importance of Paraguayan populations for the conservation of the species.A pesar de repetidas referencias sobre la presencia de la especie en Paraguay, el estado de Penelope obscura sigue siendo debatido. Para aclarar los datos disponibles se provee una revisión de la literatura junto con datos de registros inéditos modernos que comprueban la presencia de la especie en Paraguay. Los limites de especies adentro del complejo obscura no están bien definidos, y por eso incluimos una discusión breve e la importancia potencial de las poblaciones Paraguayas para la conservación de la especie

Phylogenetic Signal Dissection Identifies the Root of Starfishes

Relationships within the class Asteroidea have remained controversial for almost 100 years and, despite many attempts to resolve this problem using molecular data, no consensus has yet emerged. Using two nuclear genes and a taxon sampling covering the major asteroid clades we show that non-phylogenetic signal created by three factors - Long Branch Attraction, compositional heterogeneity and the use of poorly fitting models of evolution – have confounded accurate estimation of phylogenetic relationships. To overcome the effect of this non-phylogenetic signal we analyse the data using non-homogeneous models, site stripping and the creation of subpartitions aimed to reduce or amplify the systematic error, and calculate Bayes Factor support for a selection of previously suggested topological arrangements of asteroid orders. We show that most of the previous alternative hypotheses are not supported in the most reliable data partitions, including the previously suggested placement of either Forcipulatida or Paxillosida as sister group to the other major branches. The best-supported solution places Velatida as the sister group to other asteroids, and the implications of this finding for the morphological evolution of asteroids are presented