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Nonextensivity and Tsallis Entropy in DNA Fragmentation Patterns by Ionizing Radiation
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作者 Carlos Antonio Marante Valdes Fidel Antonio Castro Smirnov +1 位作者 Oscar Rodriguez Hoyos Joao Dias de Toledo Arruda-Neto 《Journal of Modern Physics》 2012年第6期431-437,共7页
Nonextensive statistical mechanics as in Tsallis formalism was used in this study, along with the dynamical Hamiltonian rod-like DNA model and the maximum entropy criteria for Tsallis’ entropy, so as to obtain length... Nonextensive statistical mechanics as in Tsallis formalism was used in this study, along with the dynamical Hamiltonian rod-like DNA model and the maximum entropy criteria for Tsallis’ entropy, so as to obtain length distribution of plasmid fragments, after irradiation with very high doses, assuming that the system reaches metaequilibrium. By intensively working out the Grand Canonical Ensemble (used to take into account the variation of the number of base pairs) a simplified expression for Fragment Size Distribution Function (FSDF) was obtained. This expression is dependent on two parameters only, the Tsallis q value and the minimal length of the fragments. Results obtained from fittings to available experimental data were adequate and the characteristic behavior of the shortest fragments was clearly documented and reproduced by the model, a circumstance never verified from theoretical distributions. The results point to the existence of an entropy which characterizes fragmentation processes and depending only on the q entropic index. 展开更多
关键词 Nonextensive Statistics Tsallis Entropy DNA Fragment Distribution Theoretical Distribution Fragment Minimum Length DNA Data Analysis
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Uranium Metabolism Associated with Ontogenetic Growth of Birds—Case Studies with Broilers and Ducks
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作者 Joao Dias de Toledo Arruda-Neto Guacyara Tenorio Cavalcante +4 位作者 Guilherme de Paula Nogueira Tulio Eduardo Rodrigues Luiz Eduardo Correa Fonseca Mitiko Saiki Godofredo Camara Genofre 《Advances in Bioscience and Biotechnology》 2014年第9期768-776,共9页
Cobb broilers and domestic ducks, both one-day-old, were treated using ration doped with 20 ppm of uranyl nitrate. Uranium concentrations in the tibia (μg-U/g-bone) were measured by neutron activation analysis as fun... Cobb broilers and domestic ducks, both one-day-old, were treated using ration doped with 20 ppm of uranyl nitrate. Uranium concentrations in the tibia (μg-U/g-bone) were measured by neutron activation analysis as function of the animals’ age, from the neonatal period to maturity. Results show that Uranium and Calcium qualitatively follow the same metabolic pathway, and that adult ducks incorporate on average ten times more Uranium than broilers. Data interpretation shows that the Uranium clearance rate in broilers is substantially higher than that in ducks, suggesting that metabolic characteristics favoring Calcium retention in bone may hinder the elimination of Uranium in ducks. The need for further comparative biochemistry studies between Galliformes and Anseriformes is addressed. 展开更多
关键词 Cobb Broilers Domestic Ducks Uranium-Doped-Ration Uranium-Content in Bones U/Ca Metabolism Uranium Residence Times
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Global Warming and the Power-Laws of Ecology
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作者 Joao D.T.Arruda-Neto Maria C.Bittencourt-Oliveira +4 位作者 Alrenice C.Castro Tulio E.Rodrigues Joseph Harari Joel Mesa Godofredo C.Genofre 《Atmospheric and Climate Sciences》 2012年第1期8-13,共6页
A model based on Watson’s power law for the species-area relationship predicts that full global warming, projected up to the year 2050, could provoke the disappearance of roughly one-quarter of existing species. Here... A model based on Watson’s power law for the species-area relationship predicts that full global warming, projected up to the year 2050, could provoke the disappearance of roughly one-quarter of existing species. Here, an alternative approach is worked out, based on the combination of two ecology laws: Taylor and Watson’s power laws, where the former relates species variability with their mean abundance. Just how severely global warming would affect not only the number but the diversity of the surviving species is addressed by this approach, while at the same time giving indications for the post-disaster fate of the remaining species (extinction or recovery). 展开更多
关键词 Global Warming Species Extinction Ecology Power-Laws Species Variability Model
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