BRAVO CELEDÓN, MARÍA LORETO
Thumbnail Image
Preferred name
BRAVO CELEDÓN, MARÍA LORETO
Official Name
BRAVO CELEDÓN, MARÍA LORETO
Main Affiliation
Email
bravo@udd.cl
ORCID
Scopus Author ID
8392203200

Research Output

2024 2024 2023 2023 2022 2022 2021 2021 2020 2020 2019 2019 2018 2018 2017 2017 2016 2016 0.0 0.0 0.5 0.5 1.0 1.0 1.5 1.5 2.0 2.0 2.5 2.5 3.0 3.0 3.5 3.5 4.0 4.0

Filters

13
Reset filters

Settings
Now showing 1 - 10 of 13
No Thumbnail Available
Publication

Abstract 5293: A molecular classification of gastric cancer in Chilean patients

2020 , Mauricio P. Pinto , Matias Muñoz-Medel , Miguel Cordova-Delgado , Ignacio N. Retamal , Gareth Owen , Maria Loreto Bravo , ARMISEN YAÑEZ, RICARDO AMADO , Marcelo Garrido , POLI HARLOWE, MARIA CECILIA BERTA

Abstract Objective: Incidence and mortality rates of gastric cancer (GC) are characterized by their geographical heterogeneity. In Chile, GC is the leading cause of cancer death. To date, GC patients' response to standard therapies remains limited. A molecular classification of GCs may deliver better stratifications. Herein, we obtained clinical data, protein expression and genetic profiles in a cohort of Chilean patients and present a molecular classification that correlated with overall survival (OS) rates. Methods: A total of 71 patients were included. Clinical data were obtained from medical records; protein expression was analyzed by a Tissue MicroArray. We also performed Next Generation Sequencing to assess p53 status (WT or Mut). Supervised clustering was used to generate a molecular classification. Kaplan-Meier method was used to calculate OS. Hazard ratio was calculated by Cox regression. Results: We defined 5 GC subgroups: Epstein-Barr virus+ (EBV, n=9; 13%), Microsatellite Instable (MSI, n=9; 13%), E-cadherin loss (EMT-like, n=12; 17%). The remaining patients (those MSS-/EBV-/not EMT-like) were classified either as p53 WT (n=21; 30%) or p53 Mutated (n=20; 28%). According to subgroups, 5-year survival rates were: MSI=77,8%; EBV=43.2%; p53WT=43.5%; p53Mut=25% and EMT-like=16.7%. Hazard ratios for p53Mut and EMT-like were 5.1 (IC 95%: 1.16-22.41; p=0.031) and 6.81 (IC 95%: 1.48-31.24; p=0.014), respectively against the MSI group used as reference. This association is maintained in a multivariate model using age, gender and stage. Conclusions: Our study defined 5 GC subgroups. These are associated to OS rates. EMT-like and p53Mut subgroups displayed poorer survival. Future studies should explore actionable targets in these subsets in order to improve their survival. Citation Format: Mauricio P. Pinto, Matias Muñoz-Medel, Miguel Cordova-Delgado, Ignacio N. Retamal, Gareth Owen, Maria Loreto Bravo, Ricardo Armisen, Marcelo Garrido. A molecular classification of gastric cancer in Chilean patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5293.

View
No Thumbnail Available
Publication

Consistency and trust in peer data exchange systems

2016 , LEOPOLDO BERTOSSI , BRAVO CELEDÓN, MARÍA LORETO

We propose and investigate a semantics for peer data exchange systems where different peers are related by data exchange constraints and trust relationships. These two elements plus the data at the peers' sites and their local integrity constraints are made compatible via a semantics that characterizes sets of solution instances for the peers. They are the intended – possibly virtual – instances for a peer that are obtained through a data repair semantics that we introduce and investigate. The semantically correct answers from a peer to a query, the so-called peer consistent answers, are defined as those answers that are invariant under all its different solution instances. We show that solution instances can be specified as the models of logic programs with a stable model semantics. The repair semantics is based on null values as used in SQL databases, and is also of independent interest for repairs of single databases with respect to integrity constraints.

View
No Thumbnail Available
Publication

The social stratification of internal migration and daily mobility during the COVID-19 pandemic

2024 , Erick Elejalde , FERRES, LEONARDO ADRIÁN , NAVARRO, VÍCTOR , BRAVO CELEDÓN, MARÍA LORETO , Emilio Zagheni

This study leverages mobile data for 5.4 million users to unveil the complex dynamics of daily mobility and longer-term relocations in and from Santiago, Chile, during the COVID-19 pandemic, focusing on socioeconomic differentials. We estimated a relative increase in daily mobility, in 2020, for lower-income compared to higher-income regions. In contrast, longer-term relocation rose primarily among higher-income groups. These shifts indicate nuanced responses to the pandemic across socioeconomic classes. Compared to 2017, economic factors in 2020 had a stronger influence on the decision to relocate and the selection of destinations, suggesting transformations in mobility behaviors. Contrary to previously held beliefs, there was no evidence supporting a preference for rural over urban destinations, despite the surge in emigration from Santiago during the pandemic. This study enhances our understanding of how varying socioeconomic conditions interact with mobility decisions during crises and provides insights for policymakers aiming to enact fair and evidence-based measures in rapidly changing circumstances.

View
No Thumbnail Available
Publication

Shopping mall attraction and social mixing at a city scale

2018 , Mariano G. Beiró , BRAVO CELEDÓN, MARÍA LORETO , Diego Caro , Ciro Cattuto , FERRES, LEONARDO ADRIÁN , Eduardo Graells-Garrido

View
No Thumbnail Available
Publication

Breaking the breach in Latin America: A pilot study of mechanical thrombectomy in the public healthcare system in Chile

2020 , Rodrigo Rivera , Cristian Amudio , Enzo Brunetti , Pascual Catalan , Juan Gabriel Sordo , Lautaro Badilla , Daniel Echeverria , Juan Pablo Cruz , Hector Ojeda , BRAVO CELEDÓN, MARÍA LORETO , Fabian Bravo , Walter Gonzalez , Maria Luisa Orellana , Camila Pinto , Catalina Merino-Osorio , Monica Oportus , Alejandro Salazar , Raul G Nogueira

Background Mechanical Thrombectomy (MT) is the standard of care for treatment of large vessel occlusion stroke. Until the beginning of 2020 MT was not funded nor widely implemented at the public healthcare level in Chile. Objective To describe the results of a pilot program created to provide access to public MT in Santiago - Chile. Methods Analysis from a prospectively collected database of MT cases performed between September 2017 and September 2019 in one center. A stroke network was developed with a single MT capable stroke center and five primary stroke centers. The primary efficacy endpoint was the rate of functional independence (mRS 0-2) at 90 days. Successful reperfusion was defined as 2 b-3 according to the thrombolysis in cerebral infarction scale. Safety outcomes include the rates of symptomatic intracranial hemorrhage and 90-day mortality. Results A total of 100 patients were treated over the study period. Their mean age was 62.8 ± 11.8 years and median baseline National Institute of Health Stroke Scale (NIHSS) measurement was 17. Seventy-seven percent of the patients received intra venous thrombolysis. Successful reperfusion was achieved in 95% of the cases. NIHSS at 24 hours showed a median drop of 7 points from baseline (p < 0.00001) and 50% of the follow-up patients were functionally independent at 90 days. Symptomatic Intracerebral hemorrhage occurred in 5% of the patients and 90-day all case mortality was 11%. Conclusions We demonstrated the feasibility of a publicly funded MT program in Chile, with similar results as other international randomized control trials.

View
No Thumbnail Available
Publication

Query rewriting for semantic query optimization in spatial databases

2019 , Eduardo Mella , M. Andrea Rodríguez , BRAVO CELEDÓN, MARÍA LORETO , Diego Gatica

View
No Thumbnail Available
Publication

Linking physical violence to women’s mobility in Chile

2023 , CONTRERAS GÓMEZ, HUGO ALEJANDRO , CANDIA VALLEJOS, CRISTIAN ESTEBAN , TRONCOSO OLCHEVSKAIA, RODRIGO VLADISLAV , FERRES, LEONARDO ADRIÁN , BRAVO CELEDÓN, MARÍA LORETO , Bruno Lepri , RODRÍGUEZ SICKERT, CARLOS ANDRÉS

Despite increased global attention on violence against women, understanding the factors that lead to women becoming victims remains a critical challenge. Notably, the impact of domestic violence on women’s mobility—a critical determinant of their social and economic independence—has remained largely unexplored. This study bridges this gap, employing police records to quantify physical and psychological domestic violence, while leveraging mobile phone data to proxy women’s mobility. Our analyses reveal a negative correlation between physical violence and female mobility, an association that withstands robustness checks, including controls for economic independence variables like education, employment, and occupational segregation, bootstrapping of the data set, and applying a generalized propensity score matching identification strategy. The study emphasizes the potential causal role of physical violence on decreased female mobility, asserting the value of interdisciplinary research in exploring such multifaceted social phenomena to open avenues for preventive measures. The implications of this research extend into the realm of public policy and intervention development, offering new strategies to combat and ultimately eradicate domestic violence against women, thereby contributing to wider efforts toward gender equity.

View
No Thumbnail Available
Publication

The effect of Pokémon Go on the pulse of the city: a natural experiment

2017 , Eduardo Graells-garrido , FERRES, LEONARDO ADRIÁN , Diego Caro , BRAVO CELEDÓN, MARÍA LORETO

View
No Thumbnail Available
Publication

Evaluation of home detection algorithms on mobile phone data using individual-level ground truth

2021 , Luca Pappalardo , FERRES, LEONARDO ADRIÁN , Manuel Sacasa , Ciro Cattuto , BRAVO CELEDÓN, MARÍA LORETO

Inferring mobile phone users’ home location, i.e., assigning a location in space to a user based on data generated by the mobile phone network, is a central task in leveraging mobile phone data to study social and urban phenomena. Despite its widespread use, home detection relies on assumptions that are difficult to check without ground truth, i.e., where the individual who owns the device resides. In this paper, we present a dataset that comprises the mobile phone activity of sixty-five participants for whom the geographical coordinates of their residence location are known. The mobile phone activity refers to Call Detail Records (CDRs), eXtended Detail Records (XDRs), and Control Plane Records (CPRs), which vary in their temporal granularity and differ in the data generation mechanism. We provide an unprecedented evaluation of the accuracy of home detection algorithms and quantify the amount of data needed for each stream to carry out successful home detection for each stream. Our work is useful for researchers and practitioners to minimize data requests and maximize the accuracy of the home antenna location.

View
No Thumbnail Available
Publication

A dataset to assess mobility changes in Chile following local quarantines

2023 , Luca Pappalardo , Giuliano Cornacchia , Navarro Aranguiz, Víctor , BRAVO CELEDÓN, MARÍA LORETO , FERRES, LEONARDO ADRIÁN

Fighting the COVID-19 pandemic, most countries have implemented non-pharmaceutical interventions like wearing masks, physical distancing, lockdown, and travel restrictions. Because of their economic and logistical effects, tracking mobility changes during quarantines is crucial in assessing their efficacy and predicting the virus spread. Unlike many other heavily affected countries, Chile implemented quarantines at a more localized level, shutting down small administrative zones, rather than the whole country or large regions. Given the non-obvious effects of these localized quarantines, tracking mobility becomes even more critical in Chile. To assess the impact on human mobility of the localized quarantines, we analyze a mobile phone dataset made available by Telefónica Chile, which comprises 31 billion eXtended Detail Records and 5.4 million users covering the period February 26th to September 20th, 2020. From these records, we derive three epidemiologically relevant metrics describing the mobility within and between comunas. The datasets made available may be useful to understand the effect of localized quarantines in containing the COVID-19 pandemic.

View