98 research outputs found
Generalized contact process on random environments
Spreading from a seed is studied by Monte Carlo simulation on a square
lattice with two types of sites affecting the rates of birth and death. These
systems exhibit a critical transition between survival and extinction. For
time- dependent background, this transition is equivalent to those found in
homogeneous systems (i.e. to directed percolation). For frozen backgrounds, the
appearance of Griffiths phase prevents the accurate analysis of this
transition. For long times in the subcritical region, spreading remains
localized in compact (rather than ramified) patches, and the average number of
occupied sites increases logarithmically in the surviving trials.Comment: 6 pages, 7 figure
Majority versus minority dynamics: Phase transition in an interacting two-state spin system
We introduce a simple model of opinion dynamics in which binary-state agents
evolve due to the influence of agents in a local neighborhood. In a single
update step, a fixed-size group is defined and all agents in the group adopt
the state of the local majority with probability p or that of the local
minority with probability 1-p. For group size G=3, there is a phase transition
at p_c=2/3 in all spatial dimensions. For p>p_c, the global majority quickly
predominates, while for p<p_c, the system is driven to a mixed state in which
the densities of agents in each state are equal. For p=p_c, the average
magnetization (the difference in the density of agents in the two states) is
conserved and the system obeys classical voter model dynamics. In one dimension
and within a Kirkwood decoupling scheme, the final magnetization in a
finite-length system has a non-trivial dependence on the initial magnetization
for all p.ne.p_c, in agreement with numerical results. At p_c, the exact 2-spin
correlation functions decay algebraically toward the value 1 and the system
coarsens as in the classical voter model.Comment: 11 pages, 3 figures, revtex4 2-column format; minor revisions for
publication in PR
Diagnosis Of Secondary Caries In Esthetic Restorations: Influence Of The Incidence Vertical Angle Of The X-ray Beam
The aim of this study was to evaluate the accuracy on the diagnosis of secondary caries-like lesions simulated on esthetic restorations of different materials, changing the incidence vertical angle (IVA) of the x-ray beam. Twenty human teeth received MOD inlay preparations. In the experimental group (n=10), a round cavity was made in the floor of the proximal box to simulate the caries-like lesion. All teeth were restored with 3 composite resins (Charisma, Filtek-Z250 and TPH-Spectrum) at 3 moments. Two radiographic images were acquired with 0° and 10° IVA. Ten observers evaluated the images using a 5-point confidence scale. Intra- and interobserver reliability was analyzed with the Interclass Correlation Coefficient and the diagnostic accuracy was evaluated using the area under the ROC curve (Az), Friedman test and Wilcoxon test (α=0.05). Higher accuracy values were obtained with 10° IVA (Az=0.66, Filtek- Z250>Az=0.56, TPH-Spectrum) compared to 0° (Az=0.55, Charisma>Az=0.37, TPH-Spectrum), though without statistically significant difference (p>0.05). The detection of secondary caries-like lesions simulated on esthetic restorations of different materials suffered no negative influence by changing the IVA of the x-ray beam.222129133Levin, L., Coval, M., Geiger, S.B., Cross-sectional radiographic survey of amalgam and resin-based composite posterior restorations (2007) Quintessence Int, 38, pp. 511-514Haak, R., Wicht, M.J., Hellmich, M., Noack, M.J., Detection of marginal defects of composite restorations with conventional and digital radiographs (2002) Eur J Oral Sci, 110, pp. 282-286Kirkevang, L.L., Vaeth, M., Wenzel, A., Prevalence and incidence of caries lesions in relation to placement and replacement of fillings: A longitudinal observational radiographic study of an adult Danish population (2009) Caries Res, 43, pp. 286-293Newman, B., Seow, W.K., Kazoullis, S., Ford, D., Holcombe, T., Clinical detection of caries in the primary dentition with and without bitewing radiography (2009) Austr Dent J, 54, pp. 23-30Anbiaee, N., Mohassel, A.R., Imanimoghaddam, M., Moazzami, S.M., A comparison of the accuracy of digital and conventional radiography in the diagnosis of recurrent caries (2010) Contemp Dent Pract, 11, pp. 25-32Nair, M.K., Tyndall, D.A., Ludlow, J.B., May, K., Ye, F., The effects of restorative material and location on the detection of simulated recurrent caries. A comparison of dental film, direct digital radiography and tuned aperture computed tomography (1998) Dentomaxillofac Radiol, 27, pp. 80-84van der Stelt, P.F., Ruttiman, U.E., Webber, R.L., Heemstra, P., In vitro study into the influence from x-ray beam angulation on the detection of artificial caries defects on interproximal radiographs (1989) Caries Res, 23, pp. 334-341Tveit, A.B., Espelid, I., Erickson, R.L., Glasspoole, E.A., Vertical angulation from X-ray beam and radiographic diagnosis of secondary caries (1991) Community Dent Oral Epidemiol, 19, pp. 333-335Akarslan, Z.Z., Akdevelioǧlu, M., Güngör, K., Erten, H., A comparison of the diagnostic accuracy of bitewing, periapical, unfiltered and filtered digital panoramic images for approximal caries detection in posterior teeth (2008) Dentomaxillofac Radiol, 37, pp. 458-463Sabbagh, J., Vreven, J., Leloup, G., Radiopacity of resin-based materials measured in film radiographs and storage phosphor plate (Digora) (2004) Oper Dent, 29, pp. 677-684Dental resin based restorative materials, 6 (10), pp. 1985-1985. , ISO:DP 4049, International standards organization (Draft Proposal), clauseMagalhães, C.S., Freitas, A.B., Moreira, A.N., Ferreira, E.F., Validity of staining and marginal ditching as criteria for diagnosis of secondary caries around occlusal amalgam restorations: An in vitro study (2009) Braz Dent J, 20, pp. 307-313Ergücü, Z., Türkün, L.S., Onem, E., Güneri, P., Comparative radiopacity of six flowable resin composites (2010) Oper Dent, 35, pp. 436-440Lasko, T.A., Bhagwat, J.G., Zou, K.H., Ohno-Machado, L., The use of receiver operating characteristic curves in biomedical informatics (2005) J Biomed Inform, 38, pp. 404-415Diniz, M.B., Rodrigues, J.A., Neuhaus, K.W., Cordeiro, R.C., Lussi, A., Influence of examiner's clinical experience on the reproducibility and accuracy of radiographic examination in detecting occlusal caries (2010) Clin Oral Investig, 14, pp. 515-523Zoellner, A., Diemer, B., Weber, H.P., Stassinakis, A., Gaengler, P., Histologic and radiographic assessment of caries-like lesions localized at the crown margin (2002) J Prosthet Dent, 88, pp. 54-59Ferreira, R.I., Haiter-Neto, F., Tabchoury, C.P., de Paiva, G.A., Bóscolo, F.N., Assessment of enamel demineralization using conventional, digital, and digitized radiography (2006) Braz Oral Res, 20, pp. 114-119Peker, I., Toraman Alkurt, M., Altunkaynak, B., Film tomography compared with film and digital bitewing radiography for proximal caries detection (2007) Dentomaxillofac Radiol, 36, pp. 495-49
Reaction Diffusion Models in One Dimension with Disorder
We study a large class of 1D reaction diffusion models with quenched disorder
using a real space renormalization group method (RSRG) which yields exact
results at large time. Particles (e.g. of several species) undergo diffusion
with random local bias (Sinai model) and react upon meeting. We obtain the
large time decay of the density of each specie, their associated universal
amplitudes, and the spatial distribution of particles. We also derive the
spectrum of exponents which characterize the convergence towards the asymptotic
states. For reactions with several asymptotic states, we analyze the dynamical
phase diagram and obtain the critical exponents at the transitions. We also
study persistence properties for single particles and for patterns. We compute
the decay exponents for the probability of no crossing of a given point by,
respectively, the single particle trajectories () or the thermally
averaged packets (). The generalized persistence exponents
associated to n crossings are also obtained. Specifying to the process or A with probabilities , we compute exactly the exponents
and characterizing the survival up to time t of a domain
without any merging or with mergings respectively, and and
characterizing the survival up to time t of a particle A without
any coalescence or with coalescences respectively.
obey hypergeometric equations and are numerically surprisingly close to pure
system exponents (though associated to a completely different diffusion
length). Additional disorder in the reaction rates, as well as some open
questions, are also discussed.Comment: 54 pages, Late
A Bayesian Modelling of Wildfires in Portugal
In the last decade wildfires became a serious problem in Portugal due to
different issues such as climatic characteristics and nature of Portuguese forest. In
order to analyse wildfire data, we employ beta regression for modelling the proportion
of burned forest area, under a Bayesian perspective. Our main goal is to find
out fire risk factors that influence the proportion of area burned and what may make
a forest type susceptible or resistant to fire. Then, we analyse wildfire data in Portugal
during 1990-1994 through Bayesian beta models t
Prevalence of potential drug-drug interactions in the intensive care unit of a Brazilian teaching hospital
The Brazilian Developments On The Regional Atmospheric Modeling System (brams 5.2): An Integrated Environmental Model Tuned For Tropical Areas
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We present a new version of the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS), in which different previous versions for weather, chemistry, and carbon cycle were unified in a single integrated modeling system software. This new version also has a new set of state-of-the-art physical parameterizations and greater computational parallel and memory usage efficiency. The description of the main model features includes several examples illustrating the quality of the transport scheme for scalars, radiative fluxes on surface, and model simulation of rainfall systems over South America at different spatial resolutions using a scale aware convective parameterization. Additionally, the simulation of the diurnal cycle of the convection and carbon dioxide concentration over the Amazon Basin, as well as carbon dioxide fluxes from biogenic processes over a large portion of South America, are shown. Atmospheric chemistry examples show the model performance in simulating near-surface carbon monoxide and ozone in the Amazon Basin and the megacity of Rio de Janeiro. For tracer transport and dispersion, the model capabilities to simulate the volcanic ash 3-D redistribution associated with the eruption of a Chilean volcano are demonstrated. The gain of computational efficiency is described in some detail. BRAMS has been applied for research and operational forecasting mainly in South America. Model results from the operational weather forecast of BRAMS on 5km grid spacing in the Center for Weather Forecasting and Climate Studies, INPE/Brazil, since 2013 are used to quantify the model skill of near-surface variables and rainfall. The scores show the reliability of BRAMS for the tropical and subtropical areas of South America. Requirements for keeping this modeling system competitive regarding both its functionalities and skills are discussed. Finally, we highlight the relevant contribution of this work to building a South American community of model developers. © Author(s) 2017.1011892222014/01563-1, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2014/01564-8, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2015/10206-0, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo306340/2011-9, Conselho Nacional de Desenvolvimento Científico e TecnológicoFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Evapotranspiração do feijoeiro irrigado em plantio direto sobre diferentes palhadas de culturas de cobertura
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