Alexandra Lefebvre - Homepage

I am a postdoctoral researcher at IBENS (ENS) and LJLL (Sorbonne Université) with Amaury Lambert and Vincent Maréchal since October 2022. I work on clustering methods for longitudinal Next-Generation-Sequencing data applied to viral evolution.

Previously I was ATER (Attaché Temporaire d'Enseignement et de Recherche - contractual assistant professor) at Sorbonne Université in Laboratoire de Probabilités, Statistique et Modélisation (LPSM) among the team Modélisation aléatoire du vivant (Stochastics and Biology Group).

In January 2022, I defended my PhD thesis funded by La Ligue Contre le Cancer and supervised by Grégory Nuel (LPSM) and Patrick Benusiglio (APHP - Sorbonne Université). I worked on exact inference in probabilistic graphical models for statistical genetics and survival analysis with applications to the Lynch syndrome.

My PhD manuscript is available [here] and my CV [here].

Contact information

• Email: alexandra.lefebvre@math.cnrs.fr
• Address:
  1. Centre interdisciplinaire de recherche en biologie (CIRB)
  2. Collège de France, 11, place Marcelin-Berthelot, 75231 Paris Cedex 05.
  3. Bâtiment B, niveau 1, Bureau 104.

Main research topics

• Computational statistics
• Probabilistic graphical models (Bayesian networks, hidden Markov models, ...)
• Survival analysis
• Statistical genetics
• Cancer and viral genetics

Publications

• Patrick Benusiglio, Florence Coulet, Alexandra Lefebvre, Alex Duval and Grégory Nuel. Overcoming the challenges associated with universal screening for Lynch syndrome in colorectal and endometrial cancer. Genetics in Medicine (2020).
• Alexandra Lefebvre and Grégory Nuel. A sum-product algorithm with polynomials for computing exact derivatives of the likelihood in Bayesian networks. Proceedings of Machine Learning Research (2018).
• Grégory Nuel, Alexandra Lefebvre and Olivier Bouaziz. Computing individual risks based on family history in genetic diseases in the presence of competing risks. Computational and Mathematical Methods in Medicine (2017).

Teaching

Total : 235 hours

2022 - 2023

• Risk inference in genetic counseling, Master 1 in Genetic counseling, Université de Paris – Faculté de Santé – UFR de Médecine (lecture + practicals).

2021 - 2022

• Statistics with R, Master 2 in Statistics, Sorbonne Université (lecture - course refresher).
• Statistical modeling, Master 1 in Mathematics and applications, Sorbonne Université (practicals).
• Analysis of multivariate data, ISUP 1, 1st year students in the institut of Statistics, Sorbonne Université, equivalent of a 3rd year graduate programm (tutorials).
• Data sciences, Bachelor 1, Sorbonne Université (tutorials + practicals).

2018 - 2020

• Linear algebra & Introduction to probability, Bachelor 1, Sorbonne Université (tutorials).

Conferences and seminars

Invited talks (symposium, conferences, seminars and committees)

• Mathématiques et Informatique Appliquées seminar at AgroParisTech, INRAE, Université Paris-Saclay, France (2022)
• AI and data science for biology at i-Bio & SCAI, Sorbonne Université, Paris, France (2021)
• Interdisciplinary seminar at Institut supérieur du calcul et des données, Sorbonne Université, Paris, France (ISCD 2021)
• Young Statisticians and Probabilists, online (YSP 2021)
• PhD student seminar of LPSM, Sorbonne Université, France (2021 & 2019)
• Interplay between Oncology, Mathematics and Numerics : focus on pre-treatment studies, online (IbOMaN 2020)
• Comité Oncogénétique des tumeurs Digestives de l'Ile-de-France at Institut Curie, Paris, France (CODIF 2020)
• Séminaire Mathématiques pour la biologie at Institut de Mathématiques de Toulouse, France (2019)

Contributed talks

• International Society for Gastrointestinal Hereditary Tumours, USA (InSiGHT, 2022)
• Mathematics of Complex Systems in Biology and Medicine at Centre International de Rencontres Mathématiques, Marseille, France (CIRM, 2020)
• Rencontre des jeunes statisticiens, Porquerolles, France (RJS, 2019)
• Statistical Methods for Post-Genomic Data, Spain & France (SMPGD, 2019 & 2018)
• Probabilistic Graphical Models, Czech Republic (PGM, 2018)
• International Workshop on Applied Probability, Hungary (IWAP, 2018)
• Journées Francophones sur les Réseaux Bayésiens et les Modèles Graphiques Probabilistes, Toulouse, France (JFRB, 2018)
• GDR Statistique et Santé, Nantes, France (2018)
• European Mathematical Genetics Meeting, Italy (EMGM, 2018)
• Statistical Analysis of Multioutcome data, United Kingdom (SAM, 2017)

Posters and flash oral presentations

• Assises de génétique humaine et médicale, Tours, France (flash oral presentation, 2020)
• International Society for Gastrointestinal Hereditary Tumours, New Zealand (InSiGHT, 2019, not presenter)
• International Biometric Conference, Spain (IBC, 2018)
• Assises de génétique humaine et médicale, Nantes, France (2018)

Consulting

• Sept. 2018 - June 2019: Consulting mission at Carnot Institut for France Active (pioneer in social finance) for developing of a new predictive model based on Cox regression to assess the risk of default of a project.

Computer and Languages

• Programming: R & fundamentals in Python.
• Languages: French (mother tongue), English (fluent +), German (intermediate -).

Organization

• Jan. - June 2021: co-organizer of the monthly seminar Stochastics and Biology at LPSM.
• Sept. 2018 - August 2019: co-organizer of the weekly PhD student seminar at LPSM.