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Search Results: 1 - 10 of 490767 matches for " R. S. Mendes "
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Comment on "Anomalous Spreading of Power-Law Quantum Wave Packets"
R. S. Mendes,C. Anteneodo
Physics , 2000,
Abstract: A family of wave packets with power law tails are employed to analyze the long time dependence of the corresponding probability density. The densities, associated to packets for free particles in the one-dimensional space, with sufficiently long tails decay asymptotically in time following a $t^{-\beta}$ law (with $\beta<1$), slower than the usual $t^{-1}$ one, including the particular case $(ln t)^2/t$ not correctly discussed in F. Lillo and R. N. Mantegna (Phys. Rev. Lett. 84, 1061 (2000)).
PET Oligomer Waste to Modify CAP Characteristics  [PDF]
L. C. Mendes, M. L. Dias, P. S. C. Pereira, L. M. R. Albuquerque
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.38082
Abstract: To develop an improved method of reusing poly(ethylene terephthalate) (PET) waste in the production chain, it was chemically modified with pentaerythritol (PENTE), resulting in PET/PENTE (60/40) oligomer. This was added to petroleum asphalt cement (CAP) in different proportions—5, 10 and 20 wt%—as a modifier of bitumen characteristics. The mixture was evaluated by thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), optical microscopy (OM) and the adhesion-peel test. The oligomer enhanced substantially the asphalt thermal stability-Tonset. OM images showed strong compatibility between components and PET’s amorphization. PET oligomer increased CAP’s wettability and the mixture presented cohesive fracture through the peel test. The mixture has excellent potential as paving material.
Nonlinear differential equations based on nonextensive Tsallis entropy and physical applications
R. S. Mendes,I. T. Pedron
Physics , 1999,
Abstract: A family of nonlinear ordinary differential equations with arbitrary order is obtained by using nonextensive concepts related to the Tsallis entropy. Applications of these equations are given here. In particular, a connection between Tsallis entropy and the one-dimensional correlated anomalous diffusion equation is established. It is also developed explicitly a WKB-like method for second order equations and it is applied to solve approximately a class of equations that contains as a special case the Thomas-Fermi equation for an atom. It is expected that the present ideas can be useful in the discussion of other nonlinear contexts.
Regularities in football goal distributions
L. C. Malacarne,R. S. Mendes
Physics , 2000, DOI: 10.1016/S0378-4371(00)00363-0
Abstract: Besides of complexities concerning to football championships, it is identified some regularities in them. These regularities refer to goal distributions by goal-players and by games. In particular, the goal distribution by goal-players it well adjusted by the Zipf-Mandelbrot law, suggesting a conection with an anomalous decay.
Symbolic sequences and Tsallis entropy
Ribeiro, H. V.;Lenzi, E. K.;Mendes, R. S.;Mendes, G. A.;da Silva, L. R.;
Brazilian Journal of Physics , 2009, DOI: 10.1590/S0103-97332009000400018
Abstract: we address this work to investigate symbolic sequences with long-range correlations by using computational simulation. we analyze sequences with two, three and four symbols that could be repeated l times, with the probability distribution p(l) ∝ 1/l μ. for these sequences, we verified that the usual entropy increases more slowly when the symbols are correlated and the tsallis entropy exhibits, for a suitable choice of q, a linear behavior. we also study the chain as a random walk-like process and observe a nonusual diffusive behavior depending on the values of the parameter μ.
Symbolic Sequences and Tsallis Entropy
H. V. Ribeiro,E. K. Lenzi,R. S. Mendes,G. A. Mendes,L. R. da Silva
Physics , 2010, DOI: 10.1590/S0103-97332009000400018
Abstract: We address this work to investigate symbolic sequences with long-range correlations by using computational simulation. We analyze sequences with two, three and four symbols that could be repeated $l$ times, with the probability distribution $p(l)\propto 1/ l^{\mu}$. For these sequences, we verified that the usual entropy increases more slowly when the symbols are correlated and the Tsallis entropy exhibits, for a suitable choice of $q$, a linear behavior. We also study the chain as a random walk-like process and observe a nonusual diffusive behavior depending on the values of the parameter $\mu$.
Quantum Corrections for Generalized Partition Functions
L. R. Evangelista,L. C. Malacarne,R. S. Mendes
Physics , 1998, DOI: 10.1016/S0378-4371(97)00617-1
Abstract: The classical limit for generalized partition functions is obtained using coherent states. In this framework it is presented a general procedure to obtain all the corrections to the classical limit. In particular, the first and second order quantum corrections are worked out explicitly, and the classical limit for the Tsallis thermostatistics is determined. The results of this work generalize the ones obtained by E. Wigner (Phys. Rev. 40 (1932) 749) for usual statistical mechanics.
q-exponential, Weibull, and q-Weibull distributions: an empirical analysis
S. Picoli Jr.,R. S. Mendes,L. C. Malacarne
Physics , 2003, DOI: 10.1016/S0378-4371(03)00071-2
Abstract: In a comparative study, the q-exponential and Weibull distributions are employed to investigate frequency distributions of basketball baskets, cyclone victims, brand-name drugs by retail sales, and highway length. In order to analyze the intermediate cases, a distribution, the q-Weibull one, which interpolates the q-exponential and Weibull ones, is introduced. It is verified that the basketball baskets distribution is well described by a q-exponential, whereas the cyclone victims and brand-name drugs by retail sales ones are better adjusted by a Weibull distribution. On the other hand, for highway length the q-exponential and Weibull distributions do not give satisfactory adjustment, being necessary to employ the q-Weibull distribution. Furthermore, the introduction of this interpolating distribution gives an illumination from the point of view of the stretched exponential against inverse power law (q-exponential with q > 1) controversy.
Identifying and modeling patterns of tetrapod vertebrate mortality rates in the Gulf of Mexico oil spill
F. J. Antonio,R. S. Mendes,S. M. Thomaz
Quantitative Biology , 2011, DOI: 10.1016/j.aquatox.2011.05.022
Abstract: The accidental oil spill in the Gulf of Mexico in 2010 has caused perceptible damage to marine and freshwater ecosystems. The large quantity of oil leaking at a constant rate and the long duration of the event caused an exponentially increasing mortality of vertebrates. Using data provided by NOAA and USFWS, we assessed the effects of this event on birds, sea turtles, and mammals. Mortality rates (measured as the number of carcasses recorded per day) were exponential for all three groups. Birds were the most affected group, as indicated by the steepest increase of mortality rates over time. For sea turtles and mammals, an exponential increase in mortality was observed after an initial delay. These exponential behaviors are consistent with a unified scenario for the mortality rate for tetrapod vertebrates. However, at least for mammals, pre-spill data seem to indicate that the growth in the mortality rate is not entirely a consequence of the spill.
Síndrome de Klippel-trenaunay: relato de um caso com envolvimento digestivo e revis o da literatura
M. Ferreira,S. Mendes,J. Torres,R. Ferreira
Jornal Português de Gastrenterologia , 2009,
Abstract: As les es vasculares s o uma causa comum de hemorragia gastrointestinal, podendo ocorrer isoladamente ou como parte de uma síndrome ou distúrbio sistémico. Os autores descrevem o caso clínico de uma paciente portadora da síndrome de Klippel-Trenaunay, anomalia vascular congénita rara, de etiologia n o esclarecida, e que se caracteriza pela tríade clínica de hemangiomas cutaneos, varicosidades e hipertrofia dos tecidos moles e ossos afectando geralmente um único membro. O envolvimento do tracto gastrointestinal é raro sendo a hemorragia digestiva baixa o sintoma mais frequente resultante do envolvimento do cólon por malforma es vasculares. A propósito do caso faz-se uma revis o da literatura no que respeita sobretudo ao diagnóstico e tratamento das complica es gastrointestinais. Vascular anomalies are a common cause of gastrointestinal hemorrhage; they can occur separately or as part of a syndrome. The authors describe the clinical case of a patient with the Klippel- Trenaunay syndrome (SKT), a rare, congenital vascular anomaly, of unknown etiology, characterized by the clinical triad of cutaneous hemangiomas, varicosities and hypertrophy of soft tissue and bones, usually affecting one extremity. Gastrointestinal involvement is rare; digestive hemorrhage is the most frequent symptom, as a result of colonic vascular malformations. The authors provide a literature review concerning the most relevant aspects of diagnosis and treatment of the gastrointestinal complications of this syndrome.
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