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1. On the K-theory of magnetic algebras: Iwatsuka case

Author

De Nittis, Giuseppe, Gomez, Jaime, and Ojito, Danilo Polo

Subjects
Mathematics - Operator Algebras, Mathematical Physics, Mathematics - K-Theory and Homology, Primary: 81R60, Secondary: 46L80, 81R60, 19K56
Abstract

In the tight-binding approximation, an Iwatsuka magnetic field is modeled by a function on $\mathbb{Z}^2$ with constant, but distinct values in the two parts of the lattice separated by a straight line of slope $\alpha\in [-\infty,\infty]$. In this paper, the $K$-theory of the magnetic $C^*$-algebras generated by an Iwatsuka magnetic field for any possible $\alpha$ is computed. One interesting aspect concerns the analysis of the behavior of the system in the transition from rational to irrational $\alpha$. It turns out that when $\alpha$ is irrational, the magnetic hull associated with the flux operator forms a Cantor set. On the other hand, for rational $\alpha$ this set coincides with the two-point compactification of $\mathbb{Z}$. This characterization, along with the use of the Pimsner-Voiculescu exact sequence, is the main ingredient for the computation of the $K$-theory. Once the $K$-theory is known, with the use of the index theory one can deduce the bulk-interface correspondence for tight-binding Hamiltonians subjected to an Iwatsuka magnetic field. Notably, it occurs that the topological quantization of the interface currents remains independent of the slope $\alpha$., Comment: 35 pages. Keywords: Magnetic algebras, Iwatsuka magnetic field, bulk-interface correspondence, $K$-theory

Published
2024

2. Almost 1-1 extensions of Furstenberg-Weiss type and test for amenability

Author

Cortez, María Isabel and Gómez, Jaime

Subjects
Mathematics - Dynamical Systems, Mathematics - Group Theory, 37B05, 37B10, 20E26
Abstract

Let $G$ be an infinite residually finite group. We show that for every minimal equicontinuous Cantor system $(Z,G)$ with a free orbit, and for every minimal extension $(Y,G)$ of $(Z,G)$, there exist a minimal almost 1-1 extension $(X,G)$ of $(Z,G)$ and a Borel equivariant map $\psi:Y\to X$ that induces an affine bijection $\psi^*$ between $M(Y,G)$ and $M(X,G)$, the spaces of invariant probability measures of $(Y,G)$ and $(X,G)$, respectively. If $Y$ is a Cantor set, then $(Y,G)$ and $(X,G)$ are Borel isomorphic, i.e., $\psi^*$ is also a homeomorphism. As an application, we show that the family of Toeplitz subshifts is a test for amenability for residually finite groups, i.e., a residually finite group $G$ is amenable if and only if every Toeplitz $G$-subshift has invariant probability measures., Comment: 19 pages. arXiv admin note: substantial text overlap with arXiv:2312.12562, We correct an error in the proof of Theorem 1. We have changed the title and the introduction, in order to emphasis the existence of Furstenberg-Weiss type almost 1-1 extensions that preserve measures

Published
2024

3. Almost automorphic systems have invariant measures

Author

Cortez, María Isabel and Gómez, Jaime

Subjects
Mathematics - Dynamical Systems, Mathematics - Group Theory, 37B05, 37B10
Abstract

Let $G$ be a non-amenable countable group. We show that every almost automorphic $G$-action on a compact Hausdorff space, with a maximal equicontinuous factor whose phase space is a Cantor set, admits invariant probability measures (this partially answers a question posed by Veech). In particular, every Toeplitz $G$-subshift has a non-empty space of invariant measures, meaning that this family of subshifts is not a test for amenability for countable groups. We prove that almost one-to-one extensions without measures ensure the existence of symbolic almost one-to-one extensions with equal characteristics. As a consequence, we obtain the most general result of this paper. Finally, as a corollary of our results, we deduce that the class of Toeplitz subshifts is not dense in the space of infinite transitive subshifts of $\Sigma^G$, unlike $G=\mathbb{Z}$., Comment: There is an error in theorem 14, which we believe cannot be corrected. We are working on a new version of this topic, which may take a little longer

Published
2023

4. Topo-isomorphisms of irregular Toeplitz subshifts for residually finite groups

Author

Gómez, Jaime

Subjects
Mathematics - Dynamical Systems, 37B05 (Primary) 37B10 (Secondary)
Abstract

For each countable residually finite group $G$, we present examples of irregular Toeplitz subshifts in $\{0,1\}^G$ that are topo-isomorphic extensions of its maximal equicontinuous factor. To achieve this, we first establish sufficient conditions for Toeplitz subshifts to have invariant probability measures as limit points of periodic invariant measures of $\{0,1\}^G$. Next, we demonstrate that the set of Toeplitz subshifts satisfying these conditions is non-empty. When the acting group $G$ is amenable, this construction provides non-regular extensions of totally disconnected metric compactifications of $G$ that are (Weyl) mean-quicontinuous dynamical systems., Comment: 23 pages, 4 figures

Published
2023

5. Stability of the Faber-Krahn inequality for the Short-time Fourier Transform

Author

Gómez, Jaime, Guerra, André, Ramos, João P. G., and Tilli, Paolo

Subjects
Mathematics - Classical Analysis and ODEs, Mathematics - Analysis of PDEs, Mathematics - Functional Analysis
Abstract

We prove a sharp quantitative version of the Faber--Krahn inequality for the short-time Fourier transform (STFT). To do so, we consider a deficit $\delta(f;\Omega)$ which measures by how much the STFT of a function $f\in L^2(\mathbb R)$ fails to be optimally concentrated on an arbitrary set $\Omega\subset \mathbb R^2$ of positive, finite measure. We then show that an optimal power of the deficit $\delta(f;\Omega)$ controls both the $L^2$-distance of $f$ to an appropriate class of Gaussians and the distance of $\Omega$ to a ball, through the Fraenkel asymmetry of $\Omega$. Our proof is completely quantitative and hence all constants are explicit. We also establish suitable generalizations of this result in the higher-dimensional context., Comment: 46 pages

Published
2023

6. Invariant measures of Toeplitz subshifts on non-amenable groups

Author

Bernales, Paulina Cecchi, Cortez, María Isabel, and Gómez, Jaime

Subjects
Mathematics - Dynamical Systems, 37B05, 37B10
Abstract

Let $G$ be a countable residually finite group (for instance $\mathbb{F}_2$) and let $\overleftarrow{G}$ be a totally disconnected metric compactification of $G$ equipped with the action of $G$ by left multiplication. For every $r\geq 1$ we construct a Toeplitz $G$-subshift $(X,\sigma,G)$, which is an almost one-to-one extension of $\overleftarrow{G}$, having $r$ ergodic measures $\nu_1, \cdots,\nu_r$ such that for every $1\leq i\leq r$ the measure-theoretic dynamical system $(X,\sigma,G,\nu_i)$ is isomorphic to $\overleftarrow{G}$ endowed with the Haar measure. The construction we propose is general (for amenable and non-amenable residually finite groups), however, we point out the differences and obstructions that could appear when the acting group is not amenable., Comment: 29 pages

Published
2023

8. Colombian surgical outcomes study insights on perioperative mortality rate, a main indicator of the lancet commission on global surgery – a prospective cohort study

Author

Pérez Rivera, Carlos J., Lozano-Suárez, Nicolás, Agudelo-Mendoza, Silvia Valentina, Bohórquez-Tarazona, Maria Paz, García-Zambrano, Laura, Lara-Espinosa, Daniela, Polania-Sandoval, Camilo Andres, Rojas-Serrano, Luisa Fernanda, Vargas-Cuéllar, María Paula, Velandia-Sánchez, Alejandro, Cabrera-Rivera, Paulo Andrés, Briceno-Ayala, Leonardo, Cruz-Reyes, Danna, Barrera Carvajal, Juan Guillermo, Cabrera-Vargas, Luis Felipe, Guevara, Oscar, Arce Polania, Laura Cristina, Buendía Barrios, Laura Natalia, Cristina Camargo Areyanes, María Isabel, Casas, Felipe, Alfaro, Valeria Cormane, García-Méndez, Juan P., Guerra, Bayron, Idarraga-Ayala, Sharon V., Abiyomaa, Akram Kadamani, Montoya, Christopher, Mosquera Paz, Manuel Santiago, Pineda, María Alejandra, Pinzón-Luna, Juliana, Bastidas, Isabella Roa, Roman Ortega, Carlos Fernando, Saavedra Henao, Juan D., SanJuan-Arias, Laura Carolina, Barreto, Vanessa, Corso, Julian, Maksoud-Garcia, Mariana, Mateus, Eliana Pineda, Zabaraín, Alejandra Vega, Mantilla-Sylvain, Fabien, Perez, Nicolas, Alzate-Ricaurte, Sergio, Bejarano, Monica, Caicedo Holguin, Isabella, García, Alberto Federico, Sanchez, Stefania Rodriguez, Santos, Felipe Bernal, Jaspe, Carlos Luna, Maria Camila Luna-Jaspe Roa, OLIVERA Bolívar, Maria Paula, Diaz, MariaFernanda Valdivieso, Agudelo, Yuli, Castillo-Aristizábal, Maria Paula, Hoyos Burgos, Juan Pablo, Maria Clara Mendoza Arango, Maria Clara, Gabriel Arroyave, Preciado, Felipe Buitrago, Cardona González, Lina María, Correa-Cote, Juan Camilo, Franco Arias, Karen Lorena, Llano Sierra, Juan Felipe, López, Gustavo, Mancero, Cesar, Parra, Sebastian, Gonzalez, Beatriz Ramirez, Daniela Sierra, Amaya Muñoz, Maria Camila, Blanco-Ramírez, Ashley, Camacho, Paul Anthony, Campillo, Jorge, Carvajal Mejia, Andrea Ximena, María Alejandra González Yamil, Osorno Villegas, Juan Carlos, Eduardo Rubio, Herrera, Santiago Sánchez, Herrera, Sebastian Sanchez, Agudelo, Tatiana, Andrade, Valentina, Pérez, Laura Arango, Ariza-Gutiérrez, Anibal, Jacobo Berrio, Torres, Natalia Cantillo, Chamorro-Rodríguez, Maria Valeria, Conde, Lucia, Feo Lee, Oscar Hernando, González Nieto, María Camila, Ibañez-Pintor, Laura Cecilia, Ochoa, Catalina, Ospina, Juan, Pérez-Ocampo, Juan José, Rojas, Esteban Portilla, Rey, Daniela Saaibi, Serrano, Eduardo, Solorza Velásquez, Sharon Michelle, Toro Cubides, Angélica María, Aguiar, Raúl, Beltrán Rincón, Diego Armando, Figueroa, Juan Sebastian, Figueroa-Casanova, Rafael, Gonzalez Mosos, Maria Fernanda, Marcia Gabriela Gómez, Osorno, Susana, Laura Palacio, Laura, Venegas, Jose, Caicedo Ramírez, Liliana Marcela, Cardona Gomez, Diana Catalina, Alejandro Fernandez Bolaños, Daniel, Fernández-Diago, Adriana, Olave Montaño, Victor David, Pastás, César, Amorocho, Silvia Marcela, Barbosa-Santibañez, Jorge, Baron, Vladimir, Cartagena-Alvarado, Alejandra, Castillo, Maria, Castillo-Florez, Maria Carolina, Dimian Mayorga, Omar David, Delgado-Nieto, Elena Leonor, Fajardo, Ernesto, Gomez Polania, Omar Leonardo, Gonzalez, Tania, Guzman Mesa, Daniel Felipe, Isaza-Restrepo, Andres, Leal, Jaime A., Medina, Camilo, Navarro-Alean, Jorge, Ocampo, Maria Antonia, Oliveros, Guillermo, Ortiz, Maria, Ortiz-Mahecha, Jorge I., Abaunza, Katherine Parra, Pulido Reyes, Felipe Antonio, Rivera-Rincón, Natalia, Carlos Alfonso Rodriguez Pinedo, Sanchez, Lizeth Rodriguez, Romero, Juan Javier, Sabogal Olarte, Juan Carlos, Salgado Tovar, Javier Mauricio, Torres, Guillermo Andrés, Vallejo, Linda, Vargas-Barato, Felipe, Vargas Patiño, Ana María, Villate León, Juan Pablo, Montañez Aldana, Miguel Angel, Norato, Chiara, Borda, Hugo Rojas, Núñez, Miguel Á Romero, Sánchez, Alejandro, López, Jose Támara, Támara P, Jose, Wilmer Fernando Botache Capera, Rojas, Rolando Medina, Juan Torres, Trujillo, Gina Catalina, Cubillos Saavedra, Gabriela Estefanía, Francisco García-Laverde, Naffah Enciso, Jussef Camilo, Betancur, Julian Arango, Cortés-Coronado, Adriana, Susana Sepúlveda Tamayo, Cardenas, Valentina Arboleda, García-Barrero, Luis Guillermo, Jhonatan Enrique Garzón-Galindo, Torres Parada, Lina Fernanda, Quintero, Alejandro Arias, Cano, David, Montoya Quintero, Kevin Fernando, Santiago Nieto Muñoz, Mejía, Paula Saza, Gomez Barrios, Jesus David, Jimeno, María Angélica, Restrepo Hernandez, Ghandi Ignacio, Rodríguez-Sequea, Adrian, Varón Cotes, Juan Carlos, Hanner Enrique Acevedo Reyes, Barandica Bolaño, Claudia Marcela, Sierra-Cote, Maria Camila, Angarita Vargas, Laura Daniela, Báez Ramírez, Alix Yurany, Rodriguez Suarez, Jose Armando, Sánchez, David Leonardo, Sandoval Rangel, Silvia Natalia, Hurtado, Edwin Ulloa, Hernández Almanza, Olga Esther, Martínez Zubiria, Rosalba Inmaculada, Muegues Salas, Angel Alexis, Becerra Cardona, Diego Alexander, Cárdenas Santamaría, Fabio Hernán, Echeverri Castaño, Juan Daniel, Echeverri Uribe, Juan Sebastián, Gaitán Buitrago, María Helena, Galvis Valencia, Luis Felipe, Sabogal, Andrea Henao, López Atehortúa, David Felipe, Molina Uribe, Juan Manuel, Peñate Suárez, Edwin Enrique, Valencia, Heiller Torres, Salazar, Marcela Velásquez, Correa, Catalina, García, Hans, Leal, Juan Hernández, Muñoz Vargas, Paula Tatiana, Bolívar Sáenz, Dínimo José, Caicedo Medina, Camilo Andrés, Garcia Riaño, Camilo Andres, Gonzalez, Stephanye Carrillo, Gómez, Jaime Lorduy, Madrid, Carlos Torres, Villa, Walter Torres, Luengas Orozco, Juan Sebastian, Capriles, Camilo Avendaño, Blanco, Carolina Diaz, Brieva Hoyos, Maria Lucía, Cantillo Moreno, Paola Andrea, Granados Mendoza, Sofía Carolina, Vizcaino Lara, José Dario, Babativa Peñuela, Karla Lizeth, Jiménez Bahamón, Paula Andrea, Maldonado Rico, Jhonier Estiven, Martínez Cortes, Duvan Ernesto, Orjuela Aragón, José Alfredo, Castro Roa, Lizeth Daniela, Gallego, Julieth Sarmiento, Herazo Meza, Marta Maria, Hernández Castillo, Anlly Caterin, Rojas Moncada, Rosa Gabriela, Casanova Bermeo, Lucia Fernanda, Cortés Otero, Oscar Fernando, Pinilla, Nicolás Diaz, Herrera Delgado, Harrison Rene, Macías Segura, Simon Alberto, Muñoz Castrillón, David Ramiro, Nuñez Romero, Luis Ramiro, Polania Andrade, Cesar Andrés, Valdez Toro, Hector Alejandro, Cardozo Parrado, Ana María, Moros, Jose Gonzalo, Nieto, Paula Andrea, Patarroyo, Jorge Mario, Perilla Martínez, Jose Luis, Gutierrez, María del Pilar Torres, Benito Flórez, Erika Johana, Gómez, Mariana Vergel, Robayo Rodriguez, Diana Ximena, Salcedo Miranda, Diego Fernando, Triviño Cortés, Maria Alejandra, Sastre, William Baquero, Bonett, Juan Sebastian, Cortes, Eliana, Duque, Pedro Fernando, Gutierrez, Carlos Enrique, Echeverry, Piedad, Motta Amar, Andrés Felipe, Torres, Lorena, Bautista, Jeremias Carvajal, Figueroa Bohórquez, David Mauricio, Quintana, Manuel Latorre, Olivera Briñez, Diego Fernando, Quintero Contreras, Marcel Leonardo, Gamboa, Raúl Vera, Zapata, Mariana Arias, Benavides Caipe, Cristhian Daniel, Betancur Acevedo, Luisa Fernanda, Zuluaga, Valentina Botero, Figueroa-Espinoza, Vanessa, Londoño-Patiño, Arbey Leandro, Moncayo-Gonzalez, Santiago, Puerta Suárez, Laura Sofia, Vargas-Arboleda, Paula Camila, Gonzalez Cera, Lisbet Sofia, Toro, Katerine Henao, de Jesus Ortiz Pino, Leobardo, Vasquez Vargas, Sergio Andrés, Zuluaga, Lency Naranjo, Garzón, Jaime Chamorro, Franco Rodriguez, Adriana Paola, Acosta Alape, Nataly Johana, Arbelaez Mariño, Andrés Felipe, Mora Herrera, Juan José, Ayala Muñoz, Javier Felipe, Camacho Pinzon, Yeiny Carina, Cárdenas Chacón, José Francisco, Peña Arenas, Liliana Andrea, Rodriguez Camargo, Gustavo Adolfo, Sánchez Arango, Carlos Alberto, Bolaños Ñañez, Daniel Mauricio, Garcés-Palacios, Diana Sofía, Ñañez Pantoja, María Alejandra, Ortega-Valencia, Omar Alejandro, Gamboa Bernal, María Paula, Lotero Gómez, Juan David, Martínez-Gutiérrez, Juan Sebastián, Morales-Gómez, Daniel, Pardo-Jiménez, Lina, Fonseca Galindo, Leon Miguel, Garcia Ramirez, Angélica Maria, Saurith Ramirez, Juan David, Barrero Montoya, Ivan Ricardo, Espitia, Santiago Cadena, Rojas, Salomé Pallares, Zapata Berrio, Laura Camila, Benavides Rodríguez, Diana Andrea, Gonzalez, Juan Carlos, Idarraga, Sharon Valentina, Márquez Rodríguez, Óscar Eduardo, Marrugo Prieto, Ivi Yohana, Soledad Machado, Laura Vanessa, Luna, Rubén, Pulido, Nicolás Navarro, Nuñez Ricardo, Federico Javier, García López, Andrea Elena, Luque, Fernando Girón, Jaramillo, Nasly Patiño, Pedraza Alonso, Néstor Fabian, Acuña Acuña Rivera JY, Javier Yecid, Guevara Cruz, Oscar Alexander, Martínez Buitrago, Juan Sebastián, Oviedo, Nathalia Montoya, Santafe Guerrero, Marcia Roxana, Chaves Cortés, Juanita Carolina, Rincón Tello, Francisco Mauricio, Bejarano Ramirez, Diana Fernanda, Cortes Mejia, Nicolas Andres, Garzon Mesa, Camilo Ernesto, Pabon, Alejandra Moncada, Triviño Alvarez, Diego Rymel, Torres, Alonso Vera, Cote Martinez, Maria Alejandra, Machado Rodriguez, Juan Manuel, Martinez, Gonzalo Nuñez, Osuna, Laura Naranjo, Roldan Garay, Andres Felipe, Amado, Daniel, Camacho-Mackenzie, Jaime, Maria Ceballos Mora, Cifuentes-Navarrete, Sara, Donoso-Samper, Andrea, Ferro, Manuel A., Gómez-Cáceres, Juan C., Gómez-Galán, Sebastián, Leiva, Ana G., Lisarazo, Juan, López-Castaño, Maria G., Martínez-Gil, Sofía, Montoya, M.J., Niño-Basto, Santiago, Ortigoza-Espitia, Sergio Andrés, Páez, Gustavo, Ramos-Anaya, Jesús William, Rozo, María J., Umana, Juan P., Amar, Andres Motta, Barrera Vargas, Andrés Felipe, Maldonado Escalante, Javier Dario, Molina Marroquin, German Ricardo, Prada Lievano, Silvia Alejandra, Vargas-Cuellar, Maria Paula, Polanía-Sandoval, Camilo A., and Cabrera-Rivera, Paulo A.

Published
2024
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10. MELD 3.0 adequately predicts mortality and renal replacement therapy requirements in patients with alcohol-associated hepatitis

Author

Díaz, Luis Antonio, Fuentes-López, Eduardo, Ayares, Gustavo, Idalsoaga, Francisco, Arnold, Jorge, Valverde, María Ayala, Perez, Diego, Gómez, Jaime, Escarate, Rodrigo, Villalón, Alejandro, Ramírez, Carolina A., Hernandez-Tejero, Maria, Zhang, Wei, Qian, Steve, Simonetto, Douglas A., Ahn, Joseph C., Buryska, Seth, Dunn, Winston, Mehta, Heer, Agrawal, Rohit, Cabezas, Joaquín, García-Carrera, Inés, Cuyàs, Berta, Poca, Maria, Soriano, German, Sarin, Shiv K., Maiwall, Rakhi, Jalal, Prasun K., Abdulsada, Saba, Higuera-de-la-Tijera, Fátima, Kulkarni, Anand V., Rao, P. Nagaraja, Salazar, Patricia Guerra, Skladaný, Lubomir, Bystrianska, Natália, Clemente-Sanchez, Ana, Villaseca-Gómez, Clara, Haider, Tehseen, Chacko, Kristina R., Romero, Gustavo A., Pollarsky, Florencia D., Restrepo, Juan Carlos, Castro-Sanchez, Susana, Toro, Luis G., Yaquich, Pamela, Mendizabal, Manuel, Garrido, Maria Laura, Marciano, Sebastián, Dirchwolf, Melisa, Vargas, Victor, Jiménez, César, Louvet, Alexandre, García-Tsao, Guadalupe, Roblero, Juan Pablo, Abraldes, Juan G., Shah, Vijay H., Kamath, Patrick S., Arrese, Marco, Singal, Ashwani K., Bataller, Ramon, and Arab, Juan Pablo

Published
2023
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14. The Impact of Mental Health on Postoperative Outcomes for Adolescents Undergoing Posterior Spinal Fusion for Idiopathic Scoliosis at a Tertiary Care Children’s Hospital in an Underserved Region

Author

Alvandi, Leila, primary, Segal, Kathryn R., additional, Debasitis, Alexandria J., additional, Xavier, Jorden L., additional, Gjonbalaj, Edina, additional, Ge, David, additional, Gomez, Jaime A., additional, Schulz, Jacob F., additional, and Fornari, Eric D., additional

Published
2024
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15. Comorbidity burden in terms of disability in patients with osteoarthritis in Mexico. The IMPACTAR registry

Author

Vega-Morales, David, Esquivel-Valerio, Jorge Antonio, Vázquez-Fuentes, Brenda Roxana, Díaz-Borjón, Alejandro, Arce-Salinas, César Alejandro, Álvarez-Hernández, Everardo, Torres-Roldán, José Fernando, Aguilera-Zepeda, José Manuel, Toledo-Infanson, Víctor, Alcántar-Luna, Ernesto, Aldrete-Velasco, Jorge Antonio, Martínez Hernández, José Luis, Gutiérrez-Gómez, Jaime José, and Espinosa-Morales, Rolando

Published
2021
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26. Wavelet Time Shift Properties Integration with Support Vector Machines

Author

Gomez, Jaime, Melgar, Ignacio, and Seijas, Juan

Subjects
Computer Science - Information Retrieval, Computer Science - Neural and Evolutionary Computing
Abstract

This paper presents a short evaluation about the integration of information derived from wavelet non-linear-time-invariant (non-LTI) projection properties using Support Vector Machines (SVM). These properties may give additional information for a classifier trying to detect known patterns hidden by noise. In the experiments we present a simple electromagnetic pulsed signal recognition scheme, where some improvement is achieved with respect to previous work. SVMs are used as a tool for information integration, exploiting some unique properties not easily found in neural networks., Comment: 11 pages

Published
2005

27. Sub-Optimum Signal Linear Detector Using Wavelets and Support Vector Machines

Author

Gomez, Jaime, Melgar, Ignacio, Seijas, Juan, and Andina, Diego

Subjects
Computer Science - Information Retrieval, Computer Science - Neural and Evolutionary Computing
Abstract

The problem of known signal detection in Additive White Gaussian Noise is considered. In previous work, a new detection scheme was introduced by the authors, and it was demonstrated that optimum performance cannot be reached in a real implementation. In this paper we analyse Support Vector Machines (SVM) as an alternative, evaluating the results in terms of Probability of detection curves for a fixed Probability of false alarm., Comment: 6 pages

Published
2005

28. Upgrading Pulse Detection with Time Shift Properties Using Wavelets and Support Vector Machines

Author

Gomez, Jaime, Melgar, Ignacio, and Seijas, Juan

Subjects
Computer Science - Information Retrieval, Computer Science - Neural and Evolutionary Computing
Abstract

Current approaches in pulse detection use domain transformations so as to concentrate frequency related information that can be distinguishable from noise. In real cases we do not know when the pulse will begin, so we need a time search process in which time windows are scheduled and analysed. Each window can contain the pulsed signal (either complete or incomplete) and / or noise. In this paper a simple search process will be introduced, allowing the algorithm to process more information, upgrading the capabilities in terms of probability of detection (Pd) and probability of false alarm (Pfa)., Comment: 6 pages

Published
2005

29. Optimum Signal Linear Detector in the Discrete Wavelet Transform-Domain

Author

Melgar, Ignacio, Gomez, Jaime, and Seijas, Juan

Subjects
Computer Science - Information Theory, Computer Science - Information Retrieval
Abstract

The problem of known signal detection in Additive White Gaussian Noise is considered. In this paper a new detection algorithm based on Discrete Wavelet Transform pre-processing and threshold comparison is introduced. Current approaches described in [7] use the maximum value obtained in the wavelet domain for decision. Here, we use all available information in the wavelet domain with excellent results. Detector performance is presented in Probability of detection curves for a fixed probability of false alarm., Comment: 6 pages

Published
2005

30. O-6 EXPLORING THE IMPACT OF INFECTIONS IN PATIENTS WITH ALCOHOL- ASSOCIATED HEPATITIS IN LATIN AMERICA

Author

Díaz, Luis Antonio, Idalsoaga, Francisco, Ayares, Gustavo, Arnold, Jorge, Maldonado, Katherine, Ayala, María, Perez, Diego, Gomez, Jaime, Escarate, Rodrigo, Fuentes, Eduardo, Roblero, Juan Pablo, Norero, Blanca, Lazarte, Raul, Velarde, José Antonio, Jacobo, Janett, Córdova, Jacqueline, Higuera-de-la-Tijera, Fátima, Varela, Jesús, Mejía, Scherezada, Silva, Rita, Melo, Cristina, Araujo, Roberta C., Pereira, Gustavo Henrique, Couto, Claudia, Bessone, Fernando, Tanno, Mario, Romero, Gustavo, Mendizabal, Manuel, Marciano, Sebastián, Gomez, Gonzalo, Dirchwolf, Melisa, Montes, Pedro, Guerra, Patricia, Ramos, Geraldine, Restrepo, Juan Carlos, Carrera, Enrique, Brahmania, Mayur, Singal, Ashwani, Bataller, Ramón, Shah, Vijay, Kamath, Patrick S., Arrese, Marco, and Arab, Juan Pablo

Published
2024
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38. Evaluation of the main technology valuation methods applied to intellectual property.

Author

Araujo Cavalcanti, Lucas, Lepratte, Leandro, Del Carmena Messina Scolaro, María, Bustos Gomez, Jaime, and de Souza Andrade, Herlandí

Abstract

Copyright of GeSec: Revista de Gestao e Secretariado is the property of Sindicato das Secretarias e Secretarios do Estado de Sao Paulo (SINSESP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2023
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39. O-25 ASSESSMENT OF MODELS FOR PREDICTING RESPONSE TO CORTICOIDS TREATMENT IN ALCOHOL-ASSOCIATED HEPATITIS: A GLOBAL COHORT STUDY

Author

Idalsoaga, Francisco, primary, Díaz, Luis Antonio, additional, Ayares, Gustavo, additional, Arnold, Jorge, additional, Dunn, Winston, additional, Li, Yanming, additional, Singal, Ashwani, additional, Simonetto, Doug, additional, Ayala-Valverde, María, additional, Perez, Diego, additional, Gomez, Jaime, additional, Escarate, Rodrigo, additional, Fuentes-López, Eduardo, additional, Ramirez, Carolina A, additional, Morales-Arraez, Dalia, additional, Zhang, Wei, additional, Qian, Steve, additional, Ahn, Joseph, additional, Buryska, Seth, additional, Mehta, Heer, additional, Waleed, Muhammad, additional, Stefanescu, Horia, additional, Horhat, Adelina, additional, Bumbu, Andreea, additional, Attar, Bashar, additional, Grawal, Rohit, additional, Cabezas, Joaquín, additional, García-Carrera, Inés, additional, Cuyàs, Berta, additional, Poca, Maria, additional, Pastor, German Soriano, additional, Sarin, Shiv K, additional, Maiwall, Rakhi, additional, Jalal, Prasun K, additional, Tijera, María Fátima Higuera-De La, additional, Kulkarni, Anand, additional, Rao P, Nagaraja, additional, Salazar, Patricia Guerra, additional, Skladaný, Lubomir, additional, Bystrianska, Natália, additional, Prado, Veronica, additional, Clemente-Sanchez, Ana, additional, Rincón, Diego, additional, Haider, Tehseen, additional, Chacko, Kristina R, additional, Romero, Gustavo A, additional, Pollarsky, Florencia D, additional, Restrepo, Juan Carlos, additional, Toro, Luis G, additional, Yaquich, Pamela, additional, Mendizabal, Manuel, additional, Garrido, Maria Laura, additional, Marciano, Sebastian, additional, Dirchwolf, Melisa, additional, Vargas, Victor, additional, Jimenez, Cesar, additional, García-Tsao, Guadalupe, additional, Ortiz, Guillermo, additional, Abraldes, Juan G, additional, Kamath, Patrick, additional, Arrese, Marco, additional, Shah, Vijay, additional, Bataller, Ramon, additional, and Arab, Juan Pablo, additional

Published
2023
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40. OP-5 ALCOHOL-ASSOCIATED HEPATITIS IN LATIN AMERICA: RESULTS FROM THE AH-LATIN STUDY

Author

Díaz, Luis Antonio, primary, Arnold, Jorge, additional, Idalsoaga, Francisco, additional, Ayares, Gustavo, additional, Ayala-Valverde, María, additional, Perez, Diego, additional, Gomez, Jaime, additional, Escarate, Rodrigo, additional, Roblero, Juan Pablo, additional, Norero, Blanca, additional, Velarde, José Antonio, additional, Jacobo, Janett, additional, Varela, Jesús, additional, Loza, Scherezada Mejía, additional, Córdova, Jacqueline, additional, Silva, Rita, additional, Rocha, Cristina Melo, additional, Araujo, Roberta C., additional, Pereira, Gustavo Henrique, additional, Couto, Claudia, additional, Bessone, Fernando, additional, Tanno, Mario, additional, Romero, Gustavo, additional, Mendizabal, Manuel, additional, Marciano, Sebastián, additional, Dirchwolf, Melisa, additional, Montes, Pedro, additional, Salazar, Patricia Guerra, additional, Ramos, Geraldine, additional, Restrepo, Juan Carlos, additional, Díaz, Gabriel, additional, Toro, Luis Guillermo, additional, Carrera, Enrique, additional, Mayur, Brahmania, additional, Ashwani, Singal, additional, Ramon, Bataller, additional, Vijay, Shah, additional, Patrick S., Kamath, additional, Arrese, Marco, additional, and Arab, Juan Pablo, additional

Published
2023
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43. Experimental Prompt Fission Neutron Spectra Comparisons for the 235,238U(n, f) and 239Pu(n, f) Reactions.

Author

Devlin, Matthew, Kelly, Keegan J., Gomez, Jaime A., O'Donnell, John M., Neudecker, Denise, Haight, Robert C., Bennett, Eames, Fotiades, Nikolaos, Ullmann, John, Wu, Ching-Yen, Henderson, Jack, Henderson, Roger, and Buckner, Matthew Q.

Subjects
FISSION neutrons, NEUTRON spectroscopy, NUCLEAR reactions, PLUTONIUM isotopes, FISSION products
Abstract

The Chi-Nu project to measure prompt fission neutron energy spectra for the major actinides has now completed two measurements, for neutron-induced fission of 239Pu and 235U for incident neutron energies from 1 to 20 MeV, and has almost completed the prompt fission neutron spectrum measurement for 238U. In addition, similar data have been taken for spontaneous fission in some other isotopes, and a measurement of fission neutron spectra from 240Pu(n, f) is in progress. These measurements are done at the same facility, with the same equipment and analyzed in a similar way. A useful way to look at such data is to examine ratios of the prompt fission neutron spectra among actinides, as some of the experimental uncertainties involved in these data are the same from isotope to isotope, making the ratios of fission neutron spectra less dependent on the experimental and analysis details. We discuss here the ratios of prompt fission neutron spectra between 239Pu(n, f) and 235U(n, f) , as well as the evolution of the mean fission neutron energy for 239Pu(n, f) and 235,238U(n, f) with increasing incident neutron energy. [ABSTRACT FROM AUTHOR]

Published
2023
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44. Experimental Prompt Fission Neutron Spectra Comparisons for the 235,238U(n, f) and 239Pu(n, f) Reactions

Author

Devlin, Matthew, primary, Kelly, Keegan J., additional, Gomez, Jaime A., additional, O’Donnell, John M., additional, Neudecker, Denise, additional, Haight, Robert C., additional, Bennett, Eames, additional, Fotiades, Nikolaos, additional, Ullmann, John, additional, Wu, Ching-Yen, additional, Henderson, Jack, additional, Henderson, Roger, additional, and Buckner, Matthew Q., additional

Published
2023
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46. Prompt Fission Neutron Spectra for Neutron-Induced Fission of 239Pu and 235U

Author

Devlin Matthew, Gomez Jaime A., Kelly Keegan J., O'Donnell John M., Haight Robert C., Taddeucci Terry N., Neudecker Denise, Wu Ching-Yen, Henderson Jack, White Morgan C., Bucher Brian, Buckner Matthew Q., Lee Hye Young, Mosby Shea M., Ullmann John L., Fotiades Nikolaos, and Henderson Roger A.

Subjects
Physics, QC1-999
Abstract

We report the current results of a large effort to accurately measure the Prompt Fission Neutron Spectra (PFNS) for neutron-induced fission of 235U and 239Pu for incident neutrons with energies from 1 to 20 MeV. The Chi-Nu experiment at the Los Alamos Neutron Science Center used an unmoderated, white spectrum of neutrons to induce fission in actinide samples that were placed inside a parallel plate avalanche counter to provide a fast fission signal. A double time-of-flight technique was used to determine the incoming and outgoing neutron energies. Two neutron detector arrays, one with 54 liquid scintillators and another with 22 lithium glass detectors, were used to detect the outgoing neutrons and measure the PFNS distributions over a wide range in outgoing neutron energy, from below 100 keV to 10 MeV. Extensive Monte Carlo modeling was used to understand the experiment response and extract the PFNS. Systematic errors and uncertainties in the method have been examined and quantified. A summary of these results for incoming energies from 1 to 5 MeV is presented here.

Published
2020
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47. Observations of poorly-known features of the 239Pu and 235U prompt fission neutron spectra

Author

Kelly Keegan J., Gomez Jaime A., O'Donnell John M., Devlin Matthew, Haight Robert C., Taddeucci Terry N., Mosby Shea M., Lee Hye Young, Neudecker Denise, Kawano Toshihiko, Lovell Amy E., Talou Patrick, White Morgan C, Ching-Yen Wu, Henderson Roger A., Henderson Jack, and Buckner Matthew Q.

Subjects
Physics, QC1-999
Abstract

Prompt fission neutron spectrum (PFNS) evaluations use provide nuclear data for the PFNS across a wide range of incident and outgoing neutron energies. However, experimental data underlying the evaluation are sparse, inconsistent, and incomplete with respect to the desired incident and outgoing energy coverage. As such, evaluations sometimes predict features of the PFNS, such those relating to multi-chance fission and pre-equilibrium pre-fission neutron emission, without any experimental validation. The Chi-Nu experiment at Los Alamos National Laboratory has recently obtained high-precision results for the 239Pu and 235U PFNS which, for the first time in both cases, have shed light on multi-chance fission and pre-equilibrium contributions to the observed fission neutron spectrum. In addition to providing the first experimental data on some of these fission properties, the angular coverage of the Chi-Nu experiment allows for the extraction of angular distributions of pre-equilibrium pre-fission neutrons. PFNS results of multi-chance fission and pre-equilibrium pre-fission neutron emission are discussed in this proceedings in terms of the observed neutron spectrum and the average PFNS energies.

Published
2020
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48. Experiments with neutron induced neutron emission from U-235, Pu-239, and graphite

Author

Danon Yaron, Blain Ezekiel, Mohindroo Kumar, Devlin Matt, J.Kelly Keegan, Gomez Jaime, and O'Donnell John

Subjects
Physics, QC1-999
Abstract

A neutron induced neutron emission experiment was conducted as the Los Alamos Neutron Science Center (LANSCE) facility at Los Alamos National Laboratory (LANL). In this experiment, a sample was placed in a well collimated neutron beam and was surrounded by an array of 28 fast neutron detectors (EJ-309). The experiment was performed with a neutron flight path of 21.5 m from the source to the sample, and 1 m from the sample to the detectors. The neutron emission from the sample was measured as a function of neutron time of flight covering an incident energy range from 0.7- 20 MeV. The samples included U-235, Pu-239, carbon (graphite), and blanks that matched the encapsulation of the sample. The measured samples were constantly cycled in and out of the neutron beam. This type of experiment measures neutron emission from all reactions occurring in the sample such as fission and elastic and inelastic scattering. Similar to the methodology previously developed at RPI [1], the measurements were compared with detailed simulations of the experiment using different cross section evaluations for the sample. The observed differences can be attributed to the evaluated neutron cross section and angular distributions. The carbon sample was used as a reference to validate both the experiment and simulation methodology and showed good agreement between experiments and simulations. A review of the experimental setup, analysis methods, and some of the results will be presented.

Published
2020
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