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A BUSCA DAS TERRAS RARAS PARA O DESENVOLVIMENTO REGIONAL: A NOVA FRONTEIRA DO DESENVOLVIMENTO NO INDUSTRIAL Open

Ricardo Daher Oliveira, Denílson Paulo Souza dos Santos, G. Santana, Iasmim Mendes Paiva, Iasmin de Souza Muniz , et al. · 2025

Industry 4.0 represents a significant transformation in production systems, driven by technologies such as artificial intelligence, the Internet of Things, advanced robotics, and big data. At the core of this revolution are Rare Earth Elem…

Black hole mimickers: from theory to observation Open

Cosimo Bambi, Ram Brustein, Vítor Cardoso, Andrew Chael, Ulf Danielsson , et al. · 2025

The black hole paradigm, while remarkably successful, raises fundamental questions-both classical and quantum-about the nature of spacetime, horizons, and singularities. Black hole mimickers, horizonless ultra-compact objects, have emerged…

Mahakala: A Python-based Modular Ray-tracing and Radiative Transfer Algorithm for Curved Spacetimes Open

Aniket Sharma, Lia Medeiros, George N. Wong, Chi‐kwan Chan, Goni Halevi , et al. · 2025

We introduce Mahakala , a Python -based, modular, radiative ray-tracing code for curved spacetimes. We employ Google’s JAX framework for accelerated automatic differentiation, which can efficiently compute Christoffel symbols directly from…

Theoretical Foundation of Black Hole Image Reconstruction Using PRIMO Open

Dimitrios Psaltis, Feryal Özel, Lia Medeiros, Tod R. Lauer · 2025

A new image-reconstruction algorithm, Principal-component Interferometric Modeling ( PRIMO ), applied to the interferometric data of the M87 black hole collected with the Event Horizon Telescope (EHT), resulted in an image that reached the…

Esquizofrenia e diabetes mellitus: impactos metabólicos do tratamento psicofarmacológico Open

Yoel Raydel Marzán De la Rosa, Adriana Catarina de Souza Oliveira, Carine Costa dos Santos, Tiago Ramos Cim, Leandro Bittencourt de Oliveira , et al. · 2025

A esquizofrenia é um transtorno psiquiátrico crônico e grave, que demanda tratamento contínuo com antipsicóticos, os quais, apesar de eficazes no controle dos sintomas, estão associados a diversos efeitos metabólicos adversos. Dentre esses…

Transtorno de estresse agudo e estresse pós-traumático: Diferenças e diagnóstico Open

Guilherme Bennett Volpato, Maria Jessica Alves Pinheiro, R. Scherer, Vinicius Studzinski da Silva, Elisa Souza Dezan , et al. · 2025

O presente estudo revisou as abordagens diagnósticas e diferenças entre transtorno de estresse agudo e pós-traumático, utilizando uma abordagem de revisão integrativa. O objetivo foi compreender as distinções entre esses dois transtornos r…

Causas e tratamento do Autismo infantil: abordagens diagnósticas Open

Jussara da Silva Brito, Barbara Umehara Juck, Gabriela Cuoco de Melo, Luís Sousa, Lia Medeiros , et al. · 2025

O presente estudo revisou as causas e tratamento do autismo infantil, utilizando uma abordagem de revisão integrativa. O objetivo foi explorar os fatores que influenciam o surgimento do Transtorno do Espectro Autista (TEA) na infância, alé…

Measuring Black Hole Light Echoes with Very Long Baseline Interferometry Open

George N. Wong, Lia Medeiros, Alejandro Cárdenas-Avendaño, James M. Stone · 2024

Light passing near a black hole can follow multiple paths from an emission source to an observer due to strong gravitational lensing. Photons following different paths take different amounts of time to reach the observer, which produces an…

Theoretical Foundation of Black Hole Image Reconstruction using PRIMO Open

Dimitrios Psaltis, Feryal Özel, Lia Medeiros, Tod R. Lauer · 2024

A new image-reconstruction algorithm, PRIMO, applied to the interferometric data of the M87 black hole collected with the Event Horizon Telescope (EHT), resulted in an image that reached the native resolution of the telescope array. PRIMO …

Mahakala: a Python-based Modular Ray-tracing and Radiative Transfer Algorithm for Curved Space-times Open

Aniket Sharma, Lia Medeiros, Chi‐kwan Chan, Goni Halevi, Patrick D. Mullen , et al. · 2023

We introduce Mahakala, a Python-based, modular, radiative ray-tracing code for curved space-times. We employ Google's JAX framework for accelerated automatic differentiation, which can efficiently compute Christoffel symbols directly from …

The Image of the M87 Black Hole Reconstructed with PRIMO Open

Lia Medeiros, Dimitrios Psaltis, Tod R. Lauer, Feryal Özel · 2023

We present a new reconstruction of the Event Horizon Telescope (EHT) image of the M87 black hole from the 2017 data set. We use PRIMO , a novel dictionary-learning-based algorithm that uses high-fidelity simulations of accreting black hole…

Principal-component Interferometric Modeling (PRIMO), an Algorithm for EHT Data. I. Reconstructing Images from Simulated EHT Observations Open

Lia Medeiros, Dimitrios Psaltis, Tod R. Lauer, Feryal Özel · 2023

The sparse interferometric coverage of the Event Horizon Telescope (EHT) poses a significant challenge for both reconstruction and model fitting of black hole images. PRIMO is a new principal components analysis-based algorithm for image r…

Principal-Component Interferometric Modeling (PRIMO), an Algorithm for EHT Data I: Reconstructing Images from Simulated EHT Observations Open

Lia Medeiros, Dimitrios Psaltis, Tod R. Lauer, Feryal Özel · 2022

The sparse interferometric coverage of the Event Horizon Telescope (EHT) poses a significant challenge for both reconstruction and model fitting of black-hole images. PRIMO is a new principal components analysis-based algorithm for image r…

A Red-noise Eigenbasis for the Reconstruction of Blobby Images Open

Pravita Hallur, Lia Medeiros, Tod R. Lauer · 2022

We demonstrate the use of an eigenbasis that is derived from principal component analysis (PCA) applied on an ensemble of random-noise images that have a “red” power spectrum; i.e., a spectrum that decreases smoothly from large to small sp…

Markov Chains for Horizons MARCH. I. Identifying Biases in Fitting Theoretical Models to Event Horizon Telescope Observations Open

Dimitrios Psaltis, Feryal Özel, Lia Medeiros, Pierre Christian, Junhan Kim , et al. · 2022

We introduce a new Markov Chain Monte Carlo (MCMC) algorithm with parallel tempering for fitting theoretical models of horizon-scale images of black holes to the interferometric data from the Event Horizon Telescope (EHT). The algorithm im…

The Variability of the Black Hole Image in M87 at the Dynamical Timescale Open

Kaushik Satapathy, Dimitrios Psaltis, Feryal Özel, Lia Medeiros, Sean Taylor Dougall , et al. · 2022

The black hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center of the M87 galaxy, this timescale (5–61 days) is comparable …

Brightness Asymmetry of Black Hole Images as a Probe of Observer Inclination Open

Lia Medeiros, Chi‐kwan Chan, Ramesh Narayan, Feryal Özel, Dimitrios Psaltis · 2022

The Event Horizon Telescope recently captured images of the supermassive black hole in the center of the M87 galaxy, which shows a ring-like emission structure with the south side only slightly brighter than the north side. This relatively…

The Variability of the Black-Hole Image in M87 at the Dynamical Time Scale Open

Kaushik Satapathy, Norbert Wex, Feryal Özel, Lia Medeiros, Sean Taylor Dougall , et al. · 2021

The black-hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center of the M87 galaxy, this timescale (5-61 days) is comparable …

Gravitational Test beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole Open

Dimitrios Psaltis, Lia Medeiros, Pierre Christian, Feryal Özel, Kazunori Akiyama , et al. · 2020

The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new and clean gravitational test of the black-hole metric in t…

Markov Chains for Horizons (MARCH). I. Identifying Biases in Fitting Theoretical Models to Event Horizon Telescope Observations Open

Dimitrios Psaltis, Feryal Özel, Lia Medeiros, Pierre Christian, Junhan Kim , et al. · 2020

We introduce a new Markov Chain Monte Carlo (MCMC) algorithm with parallel tempering for fitting theoretical models of horizon-scale images of black holes to the interferometric data from the Event Horizon Telescope (EHT). The algorithm im…

Discretization and Filtering Effects on Black Hole Images Obtained with the Event Horizon Telescope Open

Dimitrios Psaltis, Lia Medeiros, Tod R. Lauer, Chi Kwan Chan, Feryal Özel · 2020

Interferometers, such as the Event Horizon Telescope (EHT), do not directly observe the images of sources but rather measure their Fourier components at discrete spatial frequencies up to a maximum value set by the longest baseline in the …

Gravitational Test beyond the First Post-Newtonian Order with the EHT Open

Lia Medeiros · 2020

Modeling Variability in Black Hole Images Open

Lia Medeiros · 2019

The Event Horizon Telescope (EHT), a mm-wavelength very long baseline interferometer (VLBI), aims to take the first ever resolved images of black holes at event horizon scales. Interferometers detect the complex Fourier components (visibil…

GRay2: A General Purpose Geodesic Integrator for Kerr Spacetimes Open

Chi‐kwan Chan, Lia Medeiros, Feryal Özel, Dimitrios Psaltis · 2018

Fast and accurate integration of geodesics in Kerr spacetimes is an important tool in modeling the orbits of stars and the transport of radiation in the vicinities of black holes. Most existing integration algorithms employ Boyer–Lindquist…

A Model for Anisotropic Interstellar Scattering and its Application to Sgr A* Open

Dimitrios Psaltis, Geoffrey C. Bower, Lia Medeiros, Michael D. Johnson, Lindy Blackburn , et al. · 2018

Scattering in the ionized interstellar medium is commonly observed to be anisotropic, with theories of magnetohydrodynamic (MHD) turbulence explaining the anisotropy through a preferred magnetic field direction throughout the scattering re…

GRMHD Simulations of Visibility Amplitude Variability for Event Horizon Telescope Images of Sgr A* Open

Lia Medeiros, Chi‐kwan Chan, Feryal Özel, Dimitrios Psaltis, Junhan Kim , et al. · 2018

The Event Horizon Telescope will generate horizon scale images of the black hole in the center of the Milky Way, Sgr A*. Image reconstruction using interferometric visibilities rests on the assumption of a stationary image. We explore the …

Variability in GRMHD Simulations of Sgr : Implications for EHT Closure Phase Observations Open

Lia Medeiros, Chi‐kwan Chan, Feryal Özel, Dimitrios Psaltis, Junhan Kim , et al. · 2017

Closure phases along different baseline triangles carry a large amount of information regarding the structures of the images of black holes in interferometric observations with the Event Horizon Telescope. We use long time span, high caden…

FAST VARIABILITY AND MILLIMETER/IR FLARES IN GRMHD MODELS OF Sgr A* FROM STRONG-FIELD GRAVITATIONAL LENSING Open

Chi‐kwan Chan, Dimitrios Psaltis, Feryal Özel, Lia Medeiros, Daniel P. Marrone , et al. · 2015

We explore the variability properties of long, high-cadence general relativistic magnetohydrodynamic (GRMHD) simulations across the electromagnetic spectrum using an efficient, GPU-based radiative transfer algorithm. We focus on both stand…

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