THE PARTITION-FUNCTION FOR AN ANYON-LIKE OSCILLATOR

We compute the partition function of an anyon-like harmonic oscillator. The well known results for both the bosonic and fermionic oscillators are then re-obtained as particular cases of our function. The technique we employ is a non-relativistic version of the Green function method used in the computation of one-loop effective actions of quantum field theory.

EVOLUTION OF ADENINE CLUSTERING IN 5S RIBOSOMAL-RNA

The frequency of adenine mononucleotides (A), dinucleotides (AA) and clusters, and the positions of clusters, were studied in 502 molecules of the 5S rRNA.All frequencies were reduced in the evolutive lines of vertebrates, plants and fungi, in parallel with increasing organismic complexity. No change was observed in invertebrates. All frequencies were increased in mitochondria, plastids and mycoplasmas. The presumed relatives to the ancestors of the organelles, Rhodobacteria alfa and Cyanobacteria, showed intermediate values, relative to the eubacterial averages. Firmibacterid showed very high number of cluster sites.Clusters were more frequent in single-stranded regions in all organisms. The routes of organelles and mycoplasmas accummulated clusters at faster rates in double-stranded regions. Rates of change were higher for AA and clusters than for A in plants, vertebrates and organeltes, higher for cluster sites and A in mycoplasmas, and higher for AA and A in fungi. These data indicated that selection pressures acted more strongly on adenine clustering than on adenine frequency.It is proposed that AA and clusters, as sites of lower informational content. have the property of tolerating positional variation in the sites of other molecules (or other regions of the same molecule) that interact with the adenines. This reasoning was consistent with the degrees of genic polymorphism. low in plants and vertebrates and high in invertebrates. In the eubacteria endosymbiontic or parasitic to eukaryotes, the more tolerant RNA would be better adapted to interactions with the homologous nucleus-derived ribosomal proteins: the intermediate values observed in their precursors were interpreted as preadaptive.Among other groups, only the Deinococcus-Thermus eubacteria showed excessive AA and cluster contents, possibly related to their peculiar tolerance to mutagens, and the Ciliates showed excessive AA contents, indicative of retention of primitive characters.

Clustering of rare earth in glasses, aluminum effect: experiments and modeling

Luminescent spectra of Eu3+-doped sol-gel glasses have been analyzed during the densification process and compared according to the presence or not of aluminum as a codoping ion. A transition temperature from hydrated to dehydroxyled environments has been found different for doped and codoped samples. However, only slight modifications have been displayed from luminescence measurements beyond this transition. To support the experimental analysis, molecular dynamics simulations have been performed to model the doped and codoped glass structures. Despite no evidence of rare earth clustering reduction due to aluminum has been found, the modeled structures have shown that the luminescent ions are mainly located in aluminum-rich domains. The synthesis of both experimental and numerical analyses has lead us to interpret the aluminum effect as responsible for differences in structure of the luminescent sites rather than for an effective dispersion of the rare earth ions. (C) 2004 Elsevier B.V. All rights reserved.

Structure, mobility and clustering of interstitial O in La2CuO4+delta in the limit of small delta

Anelastic spectra (elastic energy absorption as a function of temperature) are reported which provide evidence that excess O in La2CuO4+delta starts forming two different types of defects already at very low concentrations, where no phase separation or changes in the type of O intercalation are believed to occur. The absorption peak with the lowest activation enthalpy, H/k(B) = 5600 K, is visible at lowest values of delta and is attributed to the hopping of single interstitial O2- ions. The second process, with a slightly slower dynamics, appears at higher values of delta and soon becomes preponderant over the former process. The latter process is proposed to be due to stable pairs of O atoms and is put in connection with the formation of partially covalent bonds between interstitial and apical oxygen; such bonds would reduce the doping efficiency of excess O at increasing delta. The geometry of the interstitial O defect is discussed. O 1998 Published by Elsevier B.V. B.V. All rights reserved.

Comparative phylogeography of Trypanosoma cruzi TCIIc: New hosts, association with terrestrial ecotopes, and spatial clustering

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Insulator-to-metal transition driven by clustering of solitons in polyacetylene

It's believed that the simple Su-Schrieffer-Heeger Hamiltonian can not predict the insulator to metal transition of transpolyacetylene (t-PA). The soliton lattice configuration at a doping level y=6% still has a semiconductor gap. Disordered distributions of solitons close the gap, but the electronic states around the Fermi energy are localized. However, within the same framework, it is possible to show that a cluster of solitons can produce dramatic changes in the electronic structure, allowing an insulator-to-metal transition.

Efeito do desbaste seletivo sobre a divergência genética em progênies de Pinus caribaea Morelet var. bahamensis

The objective of this work was to study the effect of selective thinning on the genetic divergence in progenies of Pinus caribaea var. bahamensis, aiming to identify the most productive and divergent progenies for the use of improvement program. The test of progenies containing 119 progenies and two commercial controls were planted in March 1990, using 11 × 11 square lattice design, sextuple, partially balanced, disposed in lineal plots with six trees in the spacing of 3,0 × 3,0m. 13 years after planting thinning was realized (selection for DBH), with 50% selection intensity based on Multi-effect index, leaving three trees per plot in all the experiment. The evaluations were done at four situations: A (before the thinning); B (thinned trees); C (remaining trees after thinning) and D (one year after thinning). The analyzed traits were: height, diameter at breast height (DBH), volume, form of stem and wood density. The genetic divergence among the progenies was studied with aid of the canonical variables and of clustering of Tocher method, using the generalized distance matrix of Mahalanobis (D2) as estimate of the genetic similarity. The progenies were grouped in four groups in situation A, fourteen in the situation B, two in the situation C and three in the situation D. The selective thinning of the trees within of the progenies caused a change in the genetic divergence among the progenies, genetically homogenizing the progenies, as demonstrated by the generalized distances of Mahalanobis, clustering of Tocher' and canonical variables methods. The thinning made possible a high uniformity in respect to the relative contribution of the traits for the total genetic divergence. The techniques of clustering were efficient to identify groups of divergent progenies for the use hybridization and little divergent progenies for the use in backcross program.

Root trunk height as a risk factor for periodontal furcation involvement in maxillary first molars: an in vitro study.

The aim of this study was to correlate the root trunk height from the furcation openings on the buccal, mesial and distal surfaces to the cemento-enamel junction in upper first permanent molars in human beings with risk for periodontal disease progression. One hundred extracted maxillary first molars were used. Reference points and demarcations were determined from the entrance of the buccal (F1), mesial (F2) and distal (F3) furcations to the cemento-enamel junction in millimeters. The mean distances found were 3.50 mm, 4.44 mm and 4.26 mm for the buccal, mesial and distal furcations, respectively, in relation to the cemento-enamel junction. The statistical analyses were Student's t-test and Chi-square (X2). With periodontal disease progression, the buccal furcation presents a greater compromising risk due to its proximity to the cemento-enamel junction, while the mesial furcation is the most distant, comprising a lesser risk.

Orientation, building height and sky view factor as energy efficiency design parameters

The energy efficiency of buildings should be a goal at the pre-design phase, though the importance of the design variables is often neglected even during the design process. Highlighting the relevance of these design variables, this research studies the relationships of building location variables with the electrical energy consumption of residential units. The following building design parameters are considered: orientation, story height and sky view factor (SVF). The consideration of the SVF as a location variable contributes to the originality of this research. Data of electrical energy consumption and users' profiles were collected and several variables were considered for the development of an Artificial Neural Network model. This model allows the determination of the relative importance of each variable. The results show that the apartments' orientation is the most important design variable for the energy consumption, although the story height and the sky view factor play a fundamental role in that consumption too. We pointed out that building heights above twenty-four meters do not optimize the energy efficiency of the apartments and also that an increasing SVF can influence the energy consumption of an apartment according to their orientation.

Land use image classification through optimum-path forest clustering

Land use classification has been paramount in the last years, since we can identify illegal land use and also to monitor deforesting areas. Although one can find several research works in the literature that address this problem, we propose here the land use recognition by means of Optimum-Path Forest Clustering (OPF), which has never been applied to this context up to date. Experiments among Optimum-Path Forest, Mean Shift and K-Means demonstrated the robustness of OPF for automatic land use classification of images obtained by CBERS-2B and Ikonos-2 satellites. © 2011 IEEE.

Spatial clustering applied to health area

The significant volume of work accidents in the cities causes an expressive loss to society. The development of Spatial Data Mining technologies presents a new perspective for the extraction of knowledge from the correlation between conventional and spatial attributes. One of the most important techniques of the Spatial Data Mining is the Spatial Clustering, which clusters similar spatial objects to find a distribution of patterns, taking into account the geographical position of the objects. Applying this technique to the health area, will provide information that can contribute towards the planning of more adequate strategies for the prevention of work accidents. The original contribution of this work is to present an application of tools developed for Spatial Clustering which supply a set of graphic resources that have helped to discover knowledge and support for management in the work accidents area. © 2011 IEEE.