oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 211 )

2018 ( 379 )

2017 ( 396 )

2016 ( 432 )

Custom range...

Search Results: 1 - 10 of 218109 matches for " Nilton Jr. L. Rascon "
All listed articles are free for downloading (OA Articles)
Page 1 /218109
Display every page Item
Geoestatística no estudo de modelagem temporal da precipita??o
Almeida, André Q. de;Ribeiro, Aristides;Paiva, Yhasmin G.;Rascon, Nilton Jr. L.;Lima, Evaldo P.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2011, DOI: 10.1590/S1415-43662011000400004
Abstract: geostatistics analysis is a powerful tool which has been used in studies of spatial dependence. with respect to the temporal dependence, few analysis are performed with this kind of methodology. in this study, the geostatistics technique was used to adjust a model to a series of temporal values of precipitation and its performance to predict data was also evaluated. the study was carried out at the rio itapemirim basin in a series of monthly precipitation from 1940 to 2006. the adjusted model was compared to the box and jenkins model. the best geostatistics model adjusted was the one which used with 96 neighbors in the prediction and mean relative absolute error of 80.46. geostatistics methodology showed better results for estimating the monthly precipitation in relation to the sarima model (2,1,1)(0,1,1)12.
Geoestatística no estudo de modelagem temporal da precipita o Geostatistics in the temporal modeling study of precipitation
André Q. de Almeida,Aristides Ribeiro,Yhasmin G. Paiva,Nilton Jr. L. Rascon
Revista Brasileira de Engenharia Agrícola e Ambiental , 2011,
Abstract: A análise geoestatística é uma poderosa ferramenta utilizada em estudos de dependência espacial. No que tange à dependência temporal, poucas s o as análises realizadas com essa metodologia. Neste trabalho foi utilizada a técnica de geoestatística para ajustar um modelo de série temporal de precipita o, cujo poder é avaliado em predizer valores futuros. O estudo foi realizado na Bacia do Rio Itapemirim em uma série de precipita o mensal de 1940 a 2006. O modelo geoestatístico foi comparado com um modelo de séries temporais de Box e Jenkins. O modelo geoestatístico ajustado foi aquele com 96 vizinhos utilizados na previs o e erro relativo absoluto médio de 80,46. A metodologia de geoestatistica apresentou melhores resultados na estima o da precipita o mensal, em rela o ao modelo SARIMA (2,1,1)(0,1,1)12. Geostatistics analysis is a powerful tool which has been used in studies of spatial dependence. With respect to the temporal dependence, few analysis are performed with this kind of methodology. In this study, the geostatistics technique was used to adjust a model to a series of temporal values of precipitation and its performance to predict data was also evaluated. The study was carried out at the Rio Itapemirim Basin in a series of monthly precipitation from 1940 to 2006. The adjusted model was compared to the Box and Jenkins model. The best geostatistics model adjusted was the one which used with 96 neighbors in the prediction and mean relative absolute error of 80.46. Geostatistics methodology showed better results for estimating the monthly precipitation in relation to the SARIMA model (2,1,1)(0,1,1)12.
Determina o do tempo térmico para o desenvolvimento de mudas de eucalipto na fase de enraizamento Determination of thermal time for the development of eucalyptus seedlings during rooting phase
Aline S. de Oliveira,Antonio J. Steidle Neto,Aristides Ribeiro,Nilton Jr. L. Rascon
Revista Brasileira de Engenharia Agrícola e Ambiental , 2012, DOI: 10.1590/s1415-43662012001100011
Abstract: O gênero Eucalyptus possui destaque em plantios florestais comerciais em virtude de apresentar crescimento rápido e ser adaptado às condi es climáticas do Brasil. Dentre as fases de maior importancia para produ o de mudas de eucalipto via propaga o vegetativa, destaca-se a de enraizamento em raz o das exigências hídricas, nutricionais e de manejo, passíveis de comprometer a qualidade das mudas na crescente demanda silvicultural brasileira. Realizou-se esta pesquisa objetivando-se determinar a soma térmica para o enraizamento de estacas clonais de eucalipto (Eucalyptus grandis x E. urophylla) e gerar equa es de estimativa para o acúmulo de biomassa na mesma fase de produ o, com base no conceito de graus-dia (tempo térmico). O trabalho foi conduzido em casa de vegeta o climatizada no viveiro de pesquisas do Departamento de Engenharia Florestal, da Universidade Federal de Vi osa, Minas Gerais. No início do enraizamento a média da biomassa fresca das mudas foi de 0,76 ± 0,17 g e da biomassa seca de 0,17 ± 0,04 g. Ao final do enraizamento a média da biomassa fresca e seca das mudas foi de 1,49 ± 0,43 g e 0,21 ± 0,06 g, respectivamente. Para o enraizamento das estacas de eucalipto foram necessários 316,42 graus-dia acumulados. The genus Eucalyptus is important in commercial forest plantations due to its rapid growth and ability to adapt to Brazilian climatic conditions. Among the most important stages for production of eucalyptus seedlings, through vegetative propagation, rooting is highlighted due to its requirements for water, nutrients and management which may compromise the quality of seedlings growing demand in Brazilian silviculture. This study aimed to determine the thermal sum to the rooting of clonal cuttings of eucalyptus (Eucalyptus grandis x E. urophylla) and generate equations to estimate the biomass accumulation in the same stage of production, based on the concept of degree-days (thermal time). The study was conducted in an acclimatized greenhouse in the Seedling Nursery of the Department of Forestry, Universidade Federal de Vi osa, Minas Gerais State, Brazil. At the start of rooting, the mean fresh weight of seedlings was 0.76 ± 0.17 g and the dry biomass was 0.17 ± 0.04 g. At the end of rooting, the means of fresh and dry biomass of seedlings were 1.49 ± 0.43 g and 0.21 ± 0.06 g, respectively. For rooting of eucalyptus seedlings 316.42 degree-days were necessary.
Endocsopic Decompression of Intermetatarsal Nerve (EDIN) for the Treatment of Morton’s Entrapment— Multicenter Retrospective Review  [PDF]
Stephen L. Barrett, Eduard Rabat, Maria Buitrago, Vincent P. Rascon, P. David Applegate
Open Journal of Orthopedics (OJO) , 2012, DOI: 10.4236/ojo.2012.22004
Abstract: Background: The authors present the results of a four surgeon, multicenter study of endoscopic decompression for the treatment of Civinini-Morton’s entrapment of 193 interspaces. Methods: A retrospective review of 193 interspaces, which were decompressed by four different surgeons. Results: The overall success rate was high, with 92% of patients reporting a good or fair outcome. Higher success rates were reported in the 3rd interspace decompression group (95%) compared to the 2nd interspace decompression group (85%). Complications reported were minimal, with only seven cases requiring a revision with traditional neurectomy. No revisions were required in the 3rd interspace decompression group. Five of the revisions were in the 2nd interspace decompression group, with the remaining two revisions in the combined 2nd/3rd interspace decompression group. Conclusions: Endoscopic decompression for the treatment of Civinnini-Morton’s entrapment is a safe and efficacious method of treatment of this nerve entrapment, with very low complication rates and rapid return to normal activity.
Perturbation Theory for Classical Solids
C. Rascon,L. Mederos,G. Navascues
Physics , 1996, DOI: 10.1103/PhysRevLett.77.2249
Abstract: The first well founded perturbation theory for classical solid systems is presented. Theoretical approaches to thermodynamic and structural properties of the hard-sphere solid provide us with the reference system. The traditional difficulties of all previous approaches are overcome. The perturbation is a first order term in an expansion of the Helmholtz free energy functional instead of an additive {\it ad hoc} term and the proper solid reference structure is used instead of some kind of mapping into the fluid structure at some effective density. As the theory reduces to the usual liquid perturbation theory in the uniform limit, it can describe consistently the complete phase diagram. Excellent results are obtained when applied to different model systems.
Solid-to-solid isostructural transition in the hard sphere/attractive Yukawa system
C. Rascon,L. Mederos,G. Navascues
Physics , 1995, DOI: 10.1063/1.469944
Abstract: A thermodynamically consistent density functional-perturbation theory is used to study the isostructural solid-to-solid transition which takes place in the hard sphere/attractive Yukawa system when the Yukawa tail is sufficiently short-ranged. A comparison with results for the square well potential allows us to study the effect of the attractive potential form on the solid-solid transition. Reasonable agreement with simulations is found for the main transition properties as well as for the phase diagram evolution with the the range of the attractive potential.
Theoretical Approach to the Correlations of a Hard-Sphere Crystal
C. Rascon,L. Mederos,G. Navascues
Physics , 1996, DOI: 10.1103/PhysRevE.54.1261
Abstract: We present the first theoretical approach to the angular-average of the two-body correlation function $\tilde g(r)$ for simple solids. It is based on three sum rules for $\tilde g(r)$: the compressibility and virial equations and the normalization. We apply the theory to determine this correlation function for the case of the FCC solid phase of hard spheres. The agreement with simulation data is excellent over all the density range. The application to other simple systems is discussed. The approach opens a new route to perturbation theories for simple solids.
Equation of State of the Hard-Sphere Crystal
C. Rascon,L. Mederos,G. Navascues
Physics , 1996, DOI: 10.1103/PhysRevE.53.5698
Abstract: A new approach to the averaged two-particle distribution function of a crystalline phase is presented. It includes an indirect check of the merit of the Gaussian approximation for the local density and a new way to inferring values of the thermodynamic variables from simulation data. The equation of state and the compressibility of the hard-sphere FCC crystal is computed from Tarazona free energy density functional [Phys. Rev. A {\bf 31}, 2672 (1985)]. They are in excellent agreement with simulation results over the physical range of densities up to almost close packing. We also include the comparison with the results obtained by two other functional approaches which are also excellent.
Stereotactic biopsy for intracranial lesions: clinical-pathological compatibility in 60 patients
Silva, Eduardo Urbano da;Vasconcellos, Lucas Perez de;Lara Jr., Nilton Alves;Veiga, José Carlos Esteves;Lancellotti, Carmen Lúcia Penteado;Shiozawa, Pedro;
Arquivos de Neuro-Psiquiatria , 2009, DOI: 10.1590/S0004-282X2009000600019
Abstract: objective: image guided stereotactic biopsy (sb) provides cerebral tissue samples for histological analysis from minimal lesions or those that are located in deep regions, being crucial in the elaboration of therapeutic strategies, as well as the prevention of unnecessary neurosurgical interventions. method: sixty patients with central nervous lesions underwent sb from november 1999 to march 2008. they were followed up to 65 months. preoperative diagnosis was based on clinical presentation and neuro-radiological features, pathologic diagnosis, clinical outcome. the compatibility of these findings with the pathologic diagnosis was analyzed. results: considering diagnosis confirmation when inflammatory hypothesis were made, our accuracy was of 76%, with 94% of those cases having clinic-pathological correspondence after an average of 65.2 months of follow up. considering diagnosis confirmation with the preoperative hypothesis of neoplasm, our accuracy was of 69% with 90% of these cases having clinic-pathological correspondence after an average of 47.3 months of follow-up. morbidity rate was of 5% and mortality was zero. the diagnosis rate was 95%. conclusion: stereotactic biopsy represents a safe and precise method for diagnosis. anatomic and histopathological analyses have high compatibility with long-term clinical outcome.
Carbocations on zeolites: quo vadis?
Mota, Claudio J. A;Rosenbach Jr, Nilton;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011000700002
Abstract: the nature of carbocations on the zeolite surface is discussed in this account, highlighting experimental and theoretical studies. the adsorption of alkylhalides over metal-exchanged zeolites has been used to study the equilibrium between covalent alkoxides and ionic carbocations. theoretical calculations indicated that the carbocations are minima (intermediates) on the potential energy surface and stabilized by hydrogen bonds with the framework oxygen atoms. the results indicate that zeolites behave like solid solvents, stabilizing the formation of ionic species.
Page 1 /218109
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.