Pedro Luiz Ramos

Pontificia Universidad Católica de Chile

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Francisco Louzada

Universidade de São Paulo

Stefano Rivella

University of Pennsylvania

Vera Tomazella

Universidade Federal de São Carlos

Robert W. Grady

Cornell University

Paulo H. Ferreira

Universidade Federal da Bahia

Diego C. Nascimento

University of Atacama

Eduardo Ramos

Brazilian Society of Computational and Applied Mathematics

Ella Guy

Cornell University

Sara Gardenghi

Children's Hospital of Philadelphia

Patricia J. Giardina

NewYork–Presbyterian Hospital

Cooperative Institutions

Universidade de São Paulo

Brazilian Society of Computational and Applied Mathematics

Universidade Federal de São Carlos

Cornell University

Universidade Brasil

Harvard University

Children's Cancer and Blood Foundation

Petrobras (Brazil)

Universidade do Porto

Children's Hospital of Philadelphia

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Macrophage Depletion Leads to Modification of Thalassemic Phenotype.

Blood (2009)

Pedro Luiz Ramos Ella Guy Nan Chen Robert W. Grady Barry S. Coller

Ineffective erythropoiesis

Extramedullary hematopoiesis

Red Cell

Beta thalassemia

10.1182/blood.v114.22.2023.2023

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Citations (1)

Some Computational Aspects to Find Accurate Estimates for the Parameters of the Generalized Gamma distribution

arXiv (Cornell University) (2017)

Jorge Alberto Achcar Pedro Luiz Ramos Edson Zangiacomí Martínez

In this paper, we discuss computational aspects to obtain accurate inferences for the parameters of the generalized gamma (GG) distribution. Usually, the solution of the maximum likelihood estimators (MLE) for the GG distribution have no stable behavior depending on large sample sizes and good initial values to be used in the iterative numerical algorithms. From a Bayesian approach, this problem remains, but now related to the choice of prior distributions for the parameters of this model. We presented some exploratory techniques to obtain good initial values to be used in the iterative procedures and also to elicited appropriate informative priors. Finally, our proposed methodology is also considered for data sets in the presence of censorship.

Inverse-gamma distribution

Generalized gamma distribution

Sample (material)

10.48550/arxiv.1707.08090

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Macrophages Regulate Stress Erythropoiesis Through Direct Cellular Interactions Associated With Integrin β1-Focal Adhesion Kinase Signaling

Blood (2013)

Bart J. Crielaard Carla Casu Pedro Luiz Ramos Sara Gardenghi Laura Breda

Ineffective erythropoiesis

Transferrin receptor

Erythroblast

10.1182/blood.v122.21.307.307

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The Generalized Weighted Lindley Distribution

arXiv (Cornell University) (2016)

Pedro Luiz Ramos Francisco Louzada

In this paper we proposed a new lifetime distribution namely generalized weighted Lindley (GLW) distribution. The GLW distribution is a straightforwardly generalization of the weighted Lindley distribution proposed by Ghitany et al. [A two-parameter weighted Lindley distribution and its applications to survival data, Mathematics and Computers in Simulation 81, (2011) p.1190-1201], which accommodates increasing, decreasing, decreasing-increasing-decreasing, bathtub, or unimodal hazard functions, making the GWL distribution a flexible model for reliability data. We provide a significant account of mathematical properties of the new distribution. Different estimation procedures are also presented such as, the maximum likelihood estimators, method of moments,the ordinary and weighted least-squares, percentile, maximum product of spacings and minimum distance estimators. The different estimators are compared by using extensive numerical simulations Finally, we analyze two data sets for illustrative purposes, proving that the GWL outperform several usual three parameters lifetime distributions.

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A new cure rate frailty regression model based on a weighted Lindley distribution applied to stomach cancer data

Statistical Methods & Applications (2022)

Alex L. Mota Eder Angelo Milani Jeremias Leão Pedro Luiz Ramos Paulo H. Ferreira

Censoring (clinical trials)

Statistical Inference

Stomach cancer

10.1007/s10260-022-00673-y

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Ineffective Erythropoiesis in β-Thalassemia Is Characterized by Increased Iron Absorption Mediated by down Regulation of Hepcidin and up Regulation of Ferroportin.

Blood (2006)

Sara Gardenghi Maria Franca Marongiu Pedro Luiz Ramos Ella Guy Laura Breda

Ineffective erythropoiesis

Ferroportin

HAMP

10.1182/blood.v108.11.1543.1543

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Bayesian analysis of the generalized gamma distribution using non-informative priors

Statistics (2017)

Pedro Luiz Ramos Jorge Alberto Achcar Fernando Antȏnio Moala Eduardo Ramos Francisco Louzada

The Generalized gamma (GG) distribution plays an important role in statistical analysis. For this distribution, we derive non-informative priors using formal rules, such as Jeffreys prior, maximal data information prior and reference priors. We have shown that these most popular formal rules with natural ordering of parameters, lead to priors with improper posteriors. This problem is overcome by considering a prior averaging approach discussed in Berger et al. [Overall objective priors. Bayesian Analysis. 2015;10(1):189–221]. The obtained hybrid Jeffreys-reference prior is invariant under one-to-one transformations and yields a proper posterior distribution. We obtained good frequentist properties of the proposed prior using a detailed simulation study. Finally, an analysis of the maximum annual discharge of the river Rhine at Lobith is presented.

Posterior predictive distribution

Inverse-gamma distribution

Generalized gamma distribution

10.1080/02331888.2017.1327532

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Citations (26)

Hfe Modulates the Response to Erythopoietic Stress In Wt Mice by Two Distinct Mechanisms

Blood (2010)

Pedro Luiz Ramos Ella Guy Robert W. Grady Maria de Sousa Stefano Rivella

Hereditary hemochromatosis

Phlebotomy

Ineffective erythropoiesis

Ferroportin

Transferrin receptor

10.1182/blood.v116.21.4251.4251

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The Frechet distribution: Estimation and Application an Overview

arXiv (Cornell University) (2018)

Pedro Luiz Ramos Francisco Louzada Eduardo Ramos Sanku Dey

In this article, we consider the problem of estimating the parameters of the Fr\'echet distribution from both frequentist and Bayesian points of view. First we briefly describe different frequentist approaches, namely, maximum likelihood, method of moments, percentile estimators, L-moments, ordinary and weighted least squares, maximum product of spacings, maximum goodness-of-fit estimators and compare them with respect to mean relative estimates, mean squared errors and the 95\% coverage probability of the asymptotic confidence intervals using extensive numerical simulations. Next, we consider the Bayesian inference approach using reference priors. The Metropolis-Hasting algorithm is used to draw Markov Chain Monte Carlo samples, and they have in turn been used to compute the Bayes estimates and also to construct the corresponding credible intervals. Five real data sets related to the minimum flow of water on Piracicaba river in Brazil are used to illustrate the applicability of the discussed procedures.

10.48550/arxiv.1801.05327

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Citations (2)

Comments on “The Exponentiated Inverted Weibull Distribution”

Applied Mathematics & Information Sciences (2016)

Pedro Luiz Ramos Francisco Louzada

Exponentiated Weibull distribution

10.18576/amis/100501

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Citations (1)