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2,221 results on '"Alvarenga, P."'

1. Diophantine equations over the generalized Fibonacci sequences: exploring sums of powers

Author

Alvarenga, Roberto, Chaves, Ana Paula, Ramos, Maria Eduarda, Silva, Matheus, and Sosa, Marcos

Subjects
Mathematics - Number Theory
Abstract

Let (F_n)_{n} be the classical Fibonacci sequence. It is well-known that it satisfies F_{n}^2 + F_{n+1}^2 = F_{2n+1}. In this study, we explore generalizations of this Diophantine equation in several directions. First, we solve the Diophantine equation (F_{n}^{(k)})^2 + (F_{n+d}^{(k)})^2 = F_{m}^{(k)} over the k-generalized Fibonacci numbers for every k \geq 2, generalizing Chaves and Marques. Next, we solve F_{n}^{s} + F_{n+d}^{s} = F_m over the Fibonacci numbers for every s \geq 2, generalizing Luca and Oyono. Finally, we solve the Diophantine equation F_{n}^s + \cdots + F_{n+d}^s = F_m for d+1 < n and s \geq 2., Comment: 27 pages, comments are very welcome!

Published
2025

2. Fibonacci Numbers as Sums of Consecutive Terms in $k$-Generalized Fibonacci Sequence

Author

Alvarenga, Roberto, Chaves, Ana Paula, Ramos, Maria Eduarda, Silva, Matheus, and Sosa, Marcos

Subjects
Mathematics - Number Theory
Abstract

Let (F_n^{(k)})_{n\geq -(k-2)} be the k-generalized Fibonacci sequence, defined as the linear recurrence sequence whose first k terms are \(0, 0, \ldots, 0, 1\), and whose subsequent terms are determined by the sum of the preceding k terms. This article is devoted to investigating when the sum of consecutive numbers in the k-generalized Fibonacci sequence belongs to the Fibonacci sequence. Namely, given d,k \in \N, with k \geq 3, our main theorem states that there are at most finitely many n \in \N such that F_n^{(k)} + \cdots + F_{n+d}^{(k)} is a Fibonacci number. In particular, the intersection between the Fibonacci sequence and the k-generalized Fibonacci sequence is finite., Comment: Comments are welcome !

Published
2025

3. Hecke modifications of vector bundles

Author

Alvarenga, Roberto, Kaur, Inder, and Moço, Leonardo

Subjects
Mathematics - Algebraic Geometry
Abstract

Hecke modifications of vector bundles have played a significant role in several areas of mathematics. They appear in subjects ranging from number theory to complex geometry. This article intends to be a friendly introduction to the subject. We give an overview of how Hecke modifications appear in the literature, explain their origin and their importance in number theory and classical algebraic geometry. Moreover, we report the progress made in describing Hecke modifications explicitly and why these explicit descriptions are important. We describe all the Hecke modifications of the trivial rank $2$ vector bundle over a closed point of degree $5$ in the projective line, as well as all the vector bundles over a certain elliptic curve, which admit a rank $2$ and degree $0$ trace bundle as a Hecke modification. This result is not present in existing literature., Comment: Comments are welcome!

Published
2025

4. Beyond the Known: Enhancing Open Set Domain Adaptation with Unknown Exploration

Author

Silva, Lucas Fernando Alvarenga e, Santos, Samuel Felipe dos, Sebe, Nicu, and Almeida, Jurandy

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Convolutional neural networks (CNNs) can learn directly from raw data, resulting in exceptional performance across various research areas. However, factors present in non-controllable environments such as unlabeled datasets with varying levels of domain and category shift can reduce model accuracy. The Open Set Domain Adaptation (OSDA) is a challenging problem that arises when both of these issues occur together. Existing OSDA approaches in literature only align known classes or use supervised training to learn unknown classes as a single new category. In this work, we introduce a new approach to improve OSDA techniques by extracting a set of high-confidence unknown instances and using it as a hard constraint to tighten the classification boundaries. Specifically, we use a new loss constraint that is evaluated in three different ways: (1) using pristine negative instances directly; (2) using data augmentation techniques to create randomly transformed negatives; and (3) with generated synthetic negatives containing adversarial features. We analyze different strategies to improve the discriminator and the training of the Generative Adversarial Network (GAN) used to generate synthetic negatives. We conducted extensive experiments and analysis on OVANet using three widely-used public benchmarks, the Office-31, Office-Home, and VisDA datasets. We were able to achieve similar H-score to other state-of-the-art methods, while increasing the accuracy on unknown categories.

Published
2024

5. ConvBench: A Comprehensive Benchmark for 2D Convolution Primitive Evaluation

Author

Alvarenga, Lucas, Ferrari, Victor, Souza, Rafael, Pereira, Marcio, and Araujo, Guido

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Performance
Abstract

Convolution is a compute-intensive operation placed at the heart of Convolution Neural Networks (CNNs). It has led to the development of many high-performance algorithms, such as Im2col-GEMM, Winograd, and Direct-Convolution. However, the comparison of different convolution algorithms is an error-prone task as it requires specific data layouts and system resources. Failure to address these requirements might lead to unwanted time penalties. Thus, considering all processing steps within convolution algorithms is essential to comprehensively evaluate and fairly compare their performance. Furthermore, most known convolution benchmarking adopts ad-hoc testing suites with limited coverage and handmade operations. This paper proposes ConvBench, a primitive-level benchmark for the evaluation and comparison of convolution algorithms. It assesses 9243 convolution operations derived from 1097 real-world deep learning models, resulting in performance and execution breakdown graphs for a detailed evaluation. ConvBench capability is evaluated across the Sliced Convolution (SConv) algorithm. The experiments showed results faster than Im2col-GEMM in 93.6% of the convolutions. However, the use of ConvBench allowed the delving into the remaining 6.4% underperforming convolutions, uncovering a critical slowdown of 79.5% on average of SConv's packing step. This analysis underscores a potential source of optimization for SConv, opening up new paths for convolution designers to improve their algorithms., Comment: 5 pages, 3 figures, presented on MLArchSys workshop of ISCA'2024

Published
2024

8. Minas artisanal cheese as a reservoir of potentially probiotic Lacticaseibacillus paracasei GV17 and Lactococcus lactis GV103 and their functional properties and kinetic mechanisms

Author

Costa, Isabella Maciel, Miranda, Thaís Bajur Alves, Magalhães, Larissa Mirelle Mendes, Fafá, Sther Menezes, Costa, Taynan Jonatha Neves, Magalhães, Mariana Batista, Valente, Gustavo Lucas Costa, Gomes, José Erick Galindo, Assis, Débora Cristina Sampaio de, Vidal, Ana Maria Centola, Alvarenga, Verônica Ortiz, Souza, Marcelo Resende de, and Salotti-Souza, Bruna Maria

Published
2025
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14. Mexican Clinical Practice Guidelines for Adult Overweight and Obesity Management

Author

Chávez-Manzanera, Emma A., Vera-Zertuche, Juan M., Kaufer-Horwitz, Martha, Vázquez-Velázquez, Verónica, Flores-Lázaro, José R., Mireles-Zavala, Leonor, Calzada-León, Raúl, Garnica-Cuellar, Juan C., Sánchez-Muñoz, Verónica, Ramírez-Butanda, Eduardo, Hernández-González, Ricardo, Vargas-Martínez, María A., Laviada-Molina, Hugo, Violante-Ortíz, Rafael, Esquivias-Zavala, Héctor, García-García, Eduardo, Lavalle-González, Fernando J., Mancillas-Adame, Leonardo, López-Alvarenga, Juan C., Pérez-Hernández, Juan F., Soto-Fuentes, Erika V., Soriano-Cortés, Reina R., Goicoechea-Turcott, Eduardo W., Magallanes-Díaz, Gerardo, Herrera-Hernández, Miguel F., Barquera-Cervera, Simón, Vargas-Contreras, Edith, Díaz-Wionczek, Cybele B., Salmon, Morgan, Jesús, Dinorah Ramírez-De, Villaseñor-Díaz, Juan P., Peña, Javiera, Ramos-Rojas, José, Ávila-Oliver, Camila, Rada, Gabriel, Hussey, Brad, and Salas, Ximena Ramos

Published
2024
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16. Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency

Author

Pluvinage, John V, Ngo, Thomas, Fouassier, Camille, McDonagh, Maura, Holmes, Brandon B, Bartley, Christopher M, Kondapavulur, Sravani, Hurabielle, Charlotte, Bodansky, Aaron, Pai, Vincent, Hinman, Sam, Aslanpour, Ava, Alvarenga, Bonny D, Zorn, Kelsey C, Zamecnik, Colin, McCann, Adrian, Asencor, Andoni I, Huynh, Trung, Browne, Weston, Tubati, Asritha, Haney, Michael S, Douglas, Vanja C, Louine, Martineau, Cree, Bruce AC, Hauser, Stephen L, Seeley, William, Baranzini, Sergio E, Wells, James A, Spudich, Serena, Farhadian, Shelli, Ramachandran, Prashanth S, Gillum, Leslie, Hales, Chadwick M, Zikherman, Julie, Anderson, Mark S, Yazdany, Jinoos, Smith, Bryan, Nath, Avindra, Suh, Gina, Flanagan, Eoin P, Green, Ari J, Green, Ralph, Gelfand, Jeffrey M, DeRisi, Joseph L, Pleasure, Samuel J, and Wilson, Michael R

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Neurosciences, Brain Disorders, Minority Health, Autoimmune Disease, Dietary Supplements, Women's Health, Biotechnology, Nutrition, Clinical Research, 2.1 Biological and endogenous factors, Neurological, Humans, Vitamin B 12 Deficiency, Vitamin B 12, Autoantibodies, Female, Receptors, Cell Surface, Antigens, CD, Middle Aged, Autoimmune Diseases, Blood-Brain Barrier, Male, Biological Sciences, Medical and Health Sciences, Medical biotechnology, Biomedical engineering
Abstract

Vitamin B12 is critical for hematopoiesis and myelination. Deficiency can cause neurologic deficits including loss of coordination and cognitive decline. However, diagnosis relies on measurement of vitamin B12 in the blood, which may not accurately reflect the concentration in the brain. Using programmable phage display, we identified an autoantibody targeting the transcobalamin receptor (CD320) in a patient with progressive tremor, ataxia, and scanning speech. Anti-CD320 impaired cellular uptake of cobalamin (B12) in vitro by depleting its target from the cell surface. Despite a normal serum concentration, B12 was nearly undetectable in her cerebrospinal fluid (CSF). Immunosuppressive treatment and high-dose systemic B12 supplementation were associated with increased B12 in the CSF and clinical improvement. Optofluidic screening enabled isolation of a patient-derived monoclonal antibody that impaired B12 transport across an in vitro model of the blood-brain barrier (BBB). Autoantibodies targeting the same epitope of CD320 were identified in seven other patients with neurologic deficits of unknown etiology, 6% of healthy controls, and 21.4% of a cohort of patients with neuropsychiatric lupus. In 132 paired serum and CSF samples, detection of anti-CD320 in the blood predicted B12 deficiency in the brain. However, these individuals did not display any hematologic signs of B12 deficiency despite systemic CD320 impairment. Using a genome-wide CRISPR screen, we found that the low-density lipoprotein receptor serves as an alternative B12 uptake pathway in hematopoietic cells. These findings dissect the tissue specificity of B12 transport and elucidate an autoimmune neurologic condition that may be amenable to immunomodulatory treatment and nutritional supplementation.

Published
2024

17. Profiles of Quality in Three Distinct Early Childhood Programs Using the Brief Early Childhood Quality Inventory (BEQI)

Author

Abbie Raikes, Rebecca Sayre Mojgani, Jem Heinzel-Nelson Alvarenga Lima, Dawn Davis, Cecelia Cassell, Marcus Waldman, and Elsa Escalante

Abstract

Quality early childhood care and education (ECCE) is important for young children's holistic healthy development. As ECCE scales, contextually relevant and feasible measurement is needed to inform policy and programs on strengths and areas for improvement. However, few measures have been designed for use across diverse contexts. Drawing on principles of mixed methods design, this study reports on a new approach to ECCE quality measurement: the Brief Early Childhood Quality Inventory. Using data from the USA, Liberia, and Colombia, results indicate variation in the items perceived as highly relevant to each setting and in the characteristics of classrooms including the degree of child autonomy, the types of activities, and in child/educator interactions and dialogue. However, despite this variation, a small set of items indicate potential functionality as cross-country anchor items. Findings lend support to the idea that quality measures can have some common elements with room for adaptation within and across settings. Future work in this area should address the possibility that the significance of these practices for child development also varies across settings.

Published
2024
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26. Unlocking the Potential of Probiotics: A Comprehensive Review on Research, Production, and Regulation of Probiotics

Author

da Silva, Tales Fernando, Glória, Rafael de Assis, Americo, Monique Ferrary, Freitas, Andria dos Santos, de Jesus, Luis Claudio Lima, Barroso, Fernanda Alvarenga Lima, Laguna, Juliana Guimarães, Coelho-Rocha, Nina Dias, Tavares, Laisa Macedo, le Loir, Yves, Jan, Gwénaël, Guédon, Éric, and Azevedo, Vasco Ariston de Carvalho

Published
2024
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34. Holographic Ricci dark energy in Nonconservative Unimodular Gravity

Author

Alvarenga, Marcelo H., Fabris, Júlio C., Velten, Hermano, and Guimarães, Luiz Filipe

Subjects
General Relativity and Quantum Cosmology, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Theory
Abstract

The structure of unimodular gravity (UG) is invariant to a subclass of diffeomorphism, the transverse diffeomorphism, due to the unimodular condition ($\sqrt{-g}=\epsilon=cte$). Consequently, there is a freedom to define how the conservation laws of the energy-momentum tensor in unimodular gravity in the cosmological context. One of the main characteristics of the complete system of equations that describe cosmological dynamics in UG is that they form an underdetermined system if the usual conservation law of the energy-momentum tensor is not used in your structure, that is, it is necessary to insert extra information into the system to solve the complete set of equations. In this article, we propose the construction of a background cosmological model based on the description of a holographic dark energy component with a cutoff of the order of Ricci scalar in non-conservative UG. Although this choice is indeed a new addition of information to the cosmological system, the complete set of equations remains underdetermined, however, the new feature of this cosmological model is the appearance of an interaction between matter and dark energy. Indeed, this is a well-known characteristic of cosmological models in which we have holographic dark energy density. Consequently, we propose an ansatz to the interaction term $Q=\beta H \rho_{m}$, and obtain the cosmological parameters of our model. We found a viable universe model with similar characteristics to the $\Lambda \mathrm{CDM}$ model. We performed statistical analysis of the background model using the "Cosmic Chronometer" (CC) data for $H(z)$, and obtain as a result using Akaike Information Criterion (AIC), and the Bayesian Information Criterion (BIC) as model selection criteria that $\Lambda \mathrm{CDM}$ prevails as the best model. However, the proposed model is competitive when compared to the cosmological model $\omega\mathrm{CDM}$.

Published
2024

35. How VADER is your AI? Towards a definition of artificial intelligence systems appropriate for regulation

Author

Bezerra, Leonardo C. T., Brownlee, Alexander E. I., Alvarenga, Luana Ferraz, Moioli, Renan Cipriano, and Batista, Thais Vasconcelos

Subjects
Computer Science - Artificial Intelligence, I.2.0
Abstract

Artificial intelligence (AI) has driven many information and communication technology (ICT) breakthroughs. Nonetheless, the scope of ICT systems has expanded far beyond AI since the Turing test proposal. Critically, recent AI regulation proposals adopt AI definitions affecting ICT techniques, approaches, and systems that are not AI. In some cases, even works from mathematics, statistics, and engineering would be affected. Worryingly, AI misdefinitions are observed from Western societies to the Global South. In this paper, we propose a framework to score how validated as appropriately-defined for regulation (VADER) an AI definition is. Our online, publicly-available VADER framework scores the coverage of premises that should underlie AI definitions for regulation, which aim to (i) reproduce principles observed in other successful technology regulations, and (ii) include all AI techniques and approaches while excluding non-AI works. Regarding the latter, our score is based on a dataset of representative AI, non-AI ICT, and non-ICT examples. We demonstrate our contribution by reviewing the AI regulation proposals of key players, namely the United States, United Kingdom, European Union, and Brazil. Importantly, none of the proposals assessed achieve the appropriateness score, ranging from a revision need to a concrete risk to ICT systems and works from other fields.

Published
2024

39. Over 400 food resources from Brazil: evidence-based records of wild edible mushrooms

Author

Drewinski, Mariana P., Corrêa-Santos, Marina Pires, Lima, Vitor X., Lima, Felipe T., Palacio, Melissa, Borges, Maria Eduarda A., Trierveiler-Pereira, Larissa, Magnago, Altielys C., Furtado, Ariadne N. M., Lenz, Alexandre R., Silva-Filho, Alexandre G. S., Nascimento, Cristiano C., Alvarenga, Renato L. M., Gibertoni, Tatiana B., Oliveira, Jadson J. S., Baltazar, Juliano M., Neves, Maria Alice, Vargas-Isla, Ruby, Ishikawa, Noemia K., and Menolli, Jr., Nelson

Published
2024
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41. Strategic interventions in clinical randomized trials for metabolic dysfunction-associated steatotic liver disease (MASLD) and obesity in the pediatric population: a systematic review with meta-analysis and bibliometric analysis

Author

Omaña-Guzmán, Isabel, Rosas-Diaz, Marisol, Martínez-López, Yoscelina Estrella, Perez-Navarro, L. Monserrat, Diaz-Badillo, Alvaro, Alanis, Anthony, Bustamante, Alejandra, Castillo-Ruiz, Octelina, del Toro-Cisneros, Noemi, Esquivel-Hernandez, Diego Armando, Garcia-Villalobos, Gloria, Garibay-Nieto, Nayely, Garcia-Oropesa, Esperanza Milagros, Hernandez-Martinez, Juan Carlos, Lopez-Sosa, Elena Beatriz, Maldonado, Carlos, Martinez, David, Membreno, Joshua, Moctezuma-Chavez, Oscar Omar, Munguia-Cisneros, Claudia X., Nava-González, Edna J., Perales-Torres, Adriana L., Pérez-García, Adolfo, Rivera-Marrero, Hector, Valdez, Alisha, Vázquez-Chávez, Alfonso Alejandro, Ramirez-Pfeiffer, Carlos, Carter, Kathleen V., Tapia, Beatriz, Vela, Leonel, and Lopez-Alvarenga, Juan Carlos

Published
2024
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44. Strategies for crowdsourcing hearing health information: a comparative study of educational programs and volunteer-based campaigns on Wikimedia

Author

Morata, Thais C., Zucki, Fernanda, Arrigo, Adriano Jorge, Cruz, Priscila Carvalho, Gong, Wei, Matos, Hector Gabriel Corrale de, Montilha, Alexandre Alberto Pascotto, Peschanski, João Alexandre, Cardoso, Maria Julia, Lacerda, Adriana Bender Moreira, Berberian, Ana Paula, Araujo, Eliene Silva, Luders, Débora, Duarte, Josilene Luciene, Jacob, Regina Tangerino de Souza, Chadha, Shelly, Mietchen, Daniel, Rasberry, Lane, Alvarenga, Katia de Freitas, and Jacob, Lilian Cassia Bornia

Published
2024
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45. Building a Portuguese coalition for biodiversity genomics

Author

Marques, João P., Alves, Paulo C., Amorim, Isabel R., Lopes, Ricardo J., Moura, Monica, Myers, Eugene, Sim-sim, Manuela, Sousa-Santos, Carla, Alves, M. Judite, Borges, Paulo A. V., Brown, Thomas, Carneiro, Miguel, Carrapato, Carlos, Ceríaco, Luís M. P., Ciofi, Claúdio, da Silva, Luís P., Diedericks, Genevieve, Diroma, Maria Angela, Farelo, Liliana, Formenti, Giulio, Gil, Fátima, Grilo, Miguel, Iannucci, Alessio, Leitão, Henrique G., Máguas, Cristina, Mc Cartney, Ann M., Mendes, Sofia L., Moreno, João M., Morselli, Marco, Mouton, Alice, Natali, Chiara, Pereira, Fernando, Rego, Rúben M. C., Resendes, Roberto, Roxo, Guilherme, Svardal, Hannes, Trindade, Helena, Vicente, Sara, Winkler, Sylke, Alvarenga, Marcela, Amaral, Andreia J., Antunes, Agostinho, Campos, Paula F., Canário, Adelino V. M., Castilho, Rita, Castro, L. Filipe C., Crottini, Angelica, Cunha, Mónica V., Espregueira Themudo, Gonçalo, Esteves, Pedro J., Faria, Rui, Rodríguez Fernandes, Carlos, Ledoux, Jean-Baptiste, Louro, Bruno, Magalhaes, Sara, Paulo, Octávio S., Pearson, Gareth, Pimenta, João, Pina-Martins, Francisco, Santos, Teresa L., Serrão, Ester, Melo-Ferreira, José, and Sousa, Vítor C.

Published
2024
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50. To be or not to B27 positive: implications for the phenotypes of axial spondyloarthritis outcomes. Data from a large multiracial cohort from the Brazilian Registry of Spondyloarthritis

Author

Resende, Gustavo Gomes, Saad, Carla Goncalves Schahin, Marques, Claudia Diniz Lopes, Ribeiro, Sandra Lúcia Euzébio, de Oliveira Gavi, Maria Bernadete Renoldi, Yazbek, Michel Alexandre, de Oliveira Marinho, Adriana, de Cássia Menin, Rita, Ochtrop, Manuella Lima Gomes, Soares, Andressa Miozzo, Cavalcanti, Nara Gualberto, Carneiro, Jamille Nascimento, Werner de Castro, Glaucio Ricardo, Fernandes, José Mauro Carneiro, da Cruz Ribeiro E Souza, Elziane, de Menezes Alvarenga, Corina Quental, de Abreu Vieira, Rejane Maria Rodrigues, Machado, Natalia Pereira, Ximenes, Antônio Carlos, Gazzeta, Morgana Ohira, de Albuquerque, Cleandro Pires, Skare, Thelma Larocca, Waldemar Keiserman, Mauro, Kohem, Charles Lubianca, Benacon, Gabriel Sarkis, Rocha, Vítor Florêncio Santos, da Cruz Lage, Ricardo, Malheiro, Olivio Brito, Golebiovski, Rywka Tenenbaum Medeiros, Oliveira, Thauana Luiza, Duque, Ruben Horst, Londe, Ana Carolina, de Medeiros Pinheiro, Marcelo, and Sampaio-Barros, Percival Degrava

Published
2024
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