Leonardo Ferreira

Dr. Leonardo Ferreira

Big Data Institute, University of Oxford, Oxford OX3 7LF, UK
orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2016 in Information Sciences
Verified
Journal Article
Closed access
Leonardo FerreiraLeonardo Ferreira
Leonardo Ferreira
Liang ZhaoLiang Zhao
Liang Zhao

23 January 2024 in The Astrophysical Journal
Verified
Journal Article
Open access
ABAsa F. L. Bluck
Asa F. L. Bluck
CCChristopher J. Conselice
Christopher J. Conselice
KOKatherine Ormerod
Katherine Ormerod
JPJoanna M. Piotrowska
Joanna M. Piotrowska
NANathan Adams
Nathan Adams
RMRoberto Maiolino
Roberto Maiolino
We present an analysis of the quenching of star formation in massive galaxies (M * > 109.5 M ⊙) within the first 0.5–3 Gyr of the Universe’s history utilizing JWST-CEERS data. We utilize a combination of advanced statistical methods to accurately constrain the intrinsic dependence of quenching in a multidimensional and intercorrelated parameter space. Specifically, we apply random forest classification, area statistics, and a partial correlation analysis to the JWST-CEERS data. First, we identify the key testable predictions from two state-of-the-art cosmological simulations (IllustrisTNG and EAGLE). Both simulations predict that quenching should be regulated by supermassive black hole mass in the early Universe. Furthermore, both simulations identify the stellar potential (ϕ *) as the optimal proxy for black hole mass in photometric data. In photometric observations, where we have no direct constraints on black hole masses, we find that the stellar potential is the most predictive parameter of massive galaxy quenching at all epochs from z = 0–8, exactly as predicted by simulations for this sample. The stellar potential outperforms stellar mass, galaxy size, galaxy density, and Sérsic index as a predictor of quiescence at all epochs probed in JWST-CEERS. Collectively, these results strongly imply a stable quenching mechanism operating throughout cosmic history, which is closely connected to the central gravitational potential in galaxies. This connection is explained in cosmological models via massive black holes forming and growing in deep potential wells, and subsequently quenching galaxies through a mix of ejective and preventative active galactic nucleus feedback.

12 August 2020 in Nature Communications
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Journal Article
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Leonardo FerreiraLeonardo Ferreira
Leonardo Ferreira
DODidier Augusto Vega Oliveros
Didier Augusto Vega Oliveros
MCMoshé Cotacallapa
Moshé Cotacallapa
MCManoel F. Cardoso
Manoel F. Cardoso
MQMarcos G. Quiles
Marcos G. Quiles
EMElbert E. N. Macau
Elbert E. N. Macau
The number of spatiotemporal data sets has increased rapidly in the last years, which demands robust and fast methods to extract information from this kind of data. Here, we propose a network-based model, called Chronnet, for spatiotemporal data analysis. The network construction process consists of dividing a geometric space into grid cells represented by nodes connected chronologically. Strong links in the network represent consecutive recurrent events between cells. The chronnet construction process is fast, making the model suitable to process large data sets. Using artificial and real data sets, we show how chronnets can capture data properties beyond simple statistics, like frequent patterns, spatial changes, outliers, and spatiotemporal clusters. Therefore, we conclude that chronnets represent a robust tool for the analysis of spatiotemporal data sets.

23 September 2024 in International Journal of Biometeorology
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Journal Article
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NFNicole Costa Resende Ferreira
Nicole Costa Resende Ferreira
RARafaella Resende Andrade
Rafaella Resende Andrade
Leonardo FerreiraLeonardo Ferreira
Leonardo Ferreira
Brazilian livestock provides a significant fraction of the food consumed globally, making the country one of the largest producers and exporters of meat, milk and eggs. However, current advances in the production of protein from Brazilian animal origin may be directly impacted by climate change and the resulting biophysical effects. Therefore, it is strategically consistent to develop measures to deal with the resulting environmental heat stress on domesticated animal species, especially the need in developing countries. This work aims to (1) evaluate the impacts of climate change on livestock (cattle-dairy, cattle-beef, goats, sheep, pigs, poultry-general) in different regions of Brazil and (2) discuss possible response strategies, associated with animal comfort and welfare. From our results, we can draw better strategies to mitigate the impacts of climate change on livestock production. The results presented show an increase of high heat stress in South and Southeast and an increase of extreme heat stress in North and Central-West areas of Brazil. The rise in extreme heat stress tends to occur mostly during spring and summer and tends to vary considering the different evaluated species. Within the evaluated species, the ones that seem to be more affected by climate changes are Poultry, pigs, cattle-beef and general (temperature-humidity index value). The differences between the results for the five geographic regions in Brazil suggests that different mitigation measures need to be considered to cope with future heat stress in livestock. To ensure the long-term success of Brazil's influence on the global market for proteins of animal origin, it must achieve sustainable production systems more intensively.

29 August 2017 in Physical Review E
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Journal Article
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LALuiz G. A. Alves
Luiz G. A. Alves
PWPeter B. Winter
Peter B. Winter
Leonardo FerreiraLeonardo Ferreira
Leonardo Ferreira
RBRenée M. Brielmann
Renée M. Brielmann
RMRichard I. Morimoto
Richard I. Morimoto
LALuís A. N. Amaral
Luís A. N. Amaral
Reduced motor control is one of the most frequent features associated with aging and disease. Nonlinear and fractal analyses have proved to be useful in investigating human physiological alterations with age and disease. Similar findings have not been established for any of the model organisms typically studied by biologists, though. If the physiology of a simpler model organism displays the same characteristics, this fact would open a new research window on the control mechanisms that organisms use to regulate physiological processes during aging and stress. Here, we use a recently introduced animal-tracking technology to simultaneously follow tens of Caenorhabdits elegans for several hours and use tools from fractal physiology to quantitatively evaluate the effects of aging and temperature stress on nematode motility. Similar to human physiological signals, scaling analysis reveals long-range correlations in numerous motility variables, fractal properties in behavioral shifts, and fluctuation dynamics over a wide range of timescales. These properties change as a result of a superposition of age and stress-related adaptive mechanisms that regulate motility.

28 September 2021 in Scientific Reports
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Journal Article
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Leonardo FerreiraLeonardo Ferreira
Leonardo Ferreira
IHInho Hong
Inho Hong
ARAlex Rutherford
Alex Rutherford
MCManuel Cebrian
Manuel Cebrian
Protest diffusion is a cascade process that can spread over different regions of the planet. The way and the extension that this phenomenon can occur is still not properly understood. Here, we empirically investigate this question using protest data from GDELT and ICEWS, two of the most extensive and longest-running data sets freely available. We divide the globe into grid cells and construct a temporal network for each data set where nodes represent cells and links are established between nodes if their protest events co-occur. We show that the temporal networks are small-world, indicating that the cells are directly linked or separated by a few steps on average. Furthermore, the average path lengths are decreasing through the years, which suggests that the world is becoming “smaller”. The persistent temporal hubs present in both data sets indicate that protests can spread faster through the hubs. This topological feature is consistent with the hypothesis that protests can quickly diffuse from one region to any other part of the globe.