Meet the NumFOCUS Team

Board of Directors

Rosie Pongracz

Rosie Pongracz joins the board after three years as a member of the NumFOCUS Advisory Council representing IBM. She is an Engineer by training, builder by practice, and has expertise in full-stack technical marketing and sales. She obtained her degree from Carnegie Mellon in Electrical/Biomedical Engineering.

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Her current focus within the technology realm is all things data and AI, platform, and open source. She has launched over 50 products and companies and operated as a leader at both early-stage companies and large corporations. She is currently at IBM building data and AI MVPs for customers to transform their businesses.

Rosie Pongracz

Logan Kilpatrick

Logan currently leads advocacy at PathAI, a Boston based company using machine learning to improve cancer patient outcomes. Logan received his bachelor’s degree from Harvard University with a focus on Computer Science and is now a dual graduate student at Northwestern University’s School of Law and Harvard University.

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Prior to his election to the board, Logan has been serving as a member of the NumFOCUS Small Development Grants, Affiliated Projects Selection Committee, and is now co-president of the NumFOCUS Incubator. He is also currently serving as the Developer Community Advocate for the Julia Language, a NumFOCUS fiscally sponsored project, and was previously the Community Manager for the Julia Language. Logan is also on the Board of Directors at DEFNA, the organization behind DjangoCon US.

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Logan Kilpatrick

Lawrence Wilson Gray

Dr. Gray is the Head of Data Science at KPMG Spark, where he builds predictive products with machine learning and Python that are reinventing how Bookkeepers work.

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He teaches Data Science and Data Analytics at Georgetown University. He is also a frequent volunteer and committee member for PyData, PyCon, and NumFocus. He is a core contributor and maintainer for the open-source software Project, Yellowbrick. He earned his Ph.D. from Johns Hopkins University, School of Medicine in Cellular and Molecular Physiology.

Lawrence Wilson Gray

Andy Terrel

Andy Terrel received his PhD in computer science at the University of Chicago in 2010. His major emphasis of research has been on the automation of numerical methods on high performance computing resources.

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To this end, he has provided numerous contributions to a wide variety of open source projects, including the popular FEniCS project and SymPy. Dr. Terrel has held roles at universities, government laboratories, and several companies. In all of these roles, Dr. Terrel has been an expert in HPCcomputing as well as an advocate for the open source software movement. Dr. Terrel has served as chair and organizer of many scientific computing conferences including SciPy Conference, FEniCS Conference, HPC^3, and Scientific Software Days. He is an active contributor and reviewer to several scientific computing journals, in addition to being a past NumFOCUS Board Member.

Andy Terrel

Dr. Julie Hollek

Dr. Julie Hollek has been a long-time user and champion of Scientific Python and the ecosystem. She is the co-chair of the SciPy Conference and has volunteered with the conference for 10 years. She previously served on NumFOCUS’ Diversity & Inclusion in Scientific Computing (DISC) committee.

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Julie earned her Ph.D. in Astronomy from the University of Texas at Austin and was most recently the Director of Data Science at Mozilla. At Mozilla, she led teams that leveraged the SciPy stack, set strategic direction for the organization, and managed budgets. Prior to Mozilla, Julie built the Health Data Science team at Twitter and is a subject matter expert at the intersection where trust and safety meets data. Throughout her career, Julie has been committed to improving diversity, equity, inclusion, and belonging by community-building. She founded Neustar Women in Technology, supporting women technologists both internally and externally; was a PyLadies San Francisco organizer; and co-founded MozAPI, the Asian Pacific Islander employee resource group at Mozilla.

Dr. Julie Hollek

Mridul Seth

Mridul Seth is a scientific software developer at the European Spallation Source ERIC, where he focuses on creating tools for neutron science. Over the years, he has contributed to several NumFOCUS projects, including NetworkX, Econ-ARK, Scientific Python, and various initiatives within the open-source scientific ecosystem.

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Reflecting on NumFOCUS’s progress over the past decade, Mridul recognizes its significant achievements in gaining and maintaining a critical presence within the wider scientific open-source community. As a candidate for the administrative board, Mridul is committed to helping sustain this momentum and securing a robust future for NumFOCUS and its projects. He believes his expertise and collective networks within the ecosystem can support the organization in setting strategic plans. By joining the board, Mridul aims to leverage his experience and passion to further strengthen NumFOCUS and its impact on the scientific open-source community.
Mridul Seth

Technical Steering Committee

Tetsuo Koyama

A software engineer based in Japan, Tetsuo Koyama has a strong interest in scientific computing and visualization using computer graphics. As one of the primary developers of the PyVista project, he is deeply engaged in advancing open-source tools and technologies. His passion for open-source conference management and community support is reflected in his roles on the SciPy Conference management staff and as a volunteer for the NumFOCUS Election Committee.

Tetsuo Koyama

Juan Nunez-Iglesias

Juan Nunez-Iglesias has been an active contributor to scientific open source since 2012, serving on the steering councils of two NumFOCUS-sponsored projects, scikit-image and napari. His dedication to open-source sustainability has been a focus for several years, highlighted by his co-organization of the “Funding Open Source” birds-of-a-feather session at SciPy 2019.
Juan Nunez-Iglesias

Jacob Schreiber

Jacob Schreiber brings over a decade of experience in the open-source ecosystem, combining technical expertise with a deep commitment to community-driven software development. As a core developer for scikit-learn and the creator of several widely-used software packages, including apricot, pomegranate, tangermeme, and ledidi, Jacob’s contributions span general-purpose tools and specialized software for the genomics community.

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Many of these projects have been bolstered by NumFOCUS Small Development Grants, with the resulting features playing a pivotal role in their success. His efforts have earned him recognition, including the Stanford Open Science Innovator Award, and he has shared his work through dozens of talks at conferences such as PyData, ODSC, and SciPy. Additionally, Jacob has translated research-focused projects like tfmodisco-lite and bpnet-lite into user-friendly production code.
Jacob Schreiber

Eloisa Elias

Eloisa Elias is a passionate advocate for open-source software and its potential to advance humanity by making powerful tools accessible to everyone, regardless of their background. A data scientist and community leader, she has built and led six inclusive data science communities with over 9,500 members, including PyData Seattle, PyLadies Seattle, and Seattle Spark + AI.

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Through these initiatives, she promotes diversity, inclusion, and education in technology, collaborating with nonprofit organizations, governments, and enterprises. Eloisa has organized 146 world-class events for the open-source community, raising over $1.4 million and providing 730 scholarship grants to increase participation among women and minorities. Her vision is to elevate open-source software to global prominence, enabling equal access to transformative tools. Deeply grateful for the opportunity to serve, Eloisa is committed to leading with integrity, innovation, and a dedication to the open-source community.

Eloisa Elias

Sanket Verma

Sanket Verma has been an integral part of the NumFOCUS and PyData community for over eight years, championing the growth of PyData culture across India. As the leader of PyData Delhi, he organized India’s first PyData conference in 2017, which catalyzed the formation of numerous PyData chapters across the country.

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Since then, he has co-chaired six PyData conferences (Delhi and Global), organized over 40 meetups, and raised more than $300,000 to support NumFOCUS projects, earning the NumFOCUS Community Leadership Award in 2022. Currently, Sanket leads open-source initiatives for Zarr, a NumFOCUS-sponsored project, and serves on the SPEC and OSSci steering committees. His extensive experience spans governance, infrastructure support, contributor engagement, and event organization, equipping him to address the challenges of the open-source ecosystem and advance its growth effectively.

Sanket Verma

Wolf Vollprecht

Wolf Vollprecht has been deeply engaged in open-source projects, driven by a passion for scientific curiosity and the belief in the transformative impact of open source, open science, and open knowledge. Committed to maximizing the efficiency and impact of open-source funding, Wolf has contributed significantly to the NumFOCUS community by establishing the PackagingCon conference and serving as a core member of conda-forge for the past four years.

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Drawing from his experience as CTO at QuantStack, a small open-source consulting business, and as founder and CEO of the startup prefix.dev, Wolf brings a wealth of expertise to advancing the open-source ecosystem.

Wolf Vollprecht

Sophia Yang

Sophia Yang is the Head of Developer Relations at Mistral AI, where she oversees developer education, ecosystem partnerships, and community engagement. A passionate advocate for the open-source Python and AI community, Sophia has contributed to numerous open-source projects and frequently speaks at events promoting open-source initiatives.

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Her longstanding commitment to NumFOCUS includes serving on the steering committee for the HoloViz project, participating in the project incubator team and small development grants review committee, and co-chairing SciPy tutorials and PyData Global. Dedicated to fostering community growth and learning, Sophia is eager to continue advancing open-source and supporting NumFOCUS’s mission.

Sophia Yang

NumFOCUS Staff

Leah Silen

Leah Silen has been with NumFOCUS from its beginning, working with the founding board members to write the application for NumFOCUS’s nonprofit status. Before joining NumFOCUS, she worked in the nonprofit sector as a Public Relations and Program Director with a focus on community relations and fundraising. Leah has also volunteered and sat on several boards of nonprofit organizations.

Leah Silen
Executive Director

Jim Weiss

Jim Weiss joined NumFOCUS in 2017, bringing over seven years of event management experience to the organization. Prior to joining NumFOCUS, Jim worked in Washington, D.C., coordinating congressional hearings for the U.S. House of Representatives and managing events for the U.S. Air Force. Jim hails from Pennsylvania and graduated from Lafayette College.

Jim Weiss
Director of Events and Resources

Tomara Youngblood

Tomara joined NumFOCUS in 2022 as the Events Manager. Before joining NumFOCUS, she worked in municipal and non-profit recreation and event management for over 17 years. Tomara is a graduate of the University of North Texas.

Tomara Youngblood
Events Manager

Patricia Rameau

Patricia Rameau is an Events Manager at NumFOCUS. With seven years of experience in higher education, she excels at building relationships, fostering alumni engagement, and spearheading fundraising initiatives. Patricia has managed six alumni chapters across the globe and successfully hosted over 100 events. In her free time, she enjoys trying new restaurants, binge-watching thriller movies, and spending quality time with family and friends. Known for her friendly and creative approach, Patricia brings enthusiasm and expertise to every event she undertakes.

Patricia Rameau
Events Manager

Nolan Fortman

Nolan joined NumFOCUS in October of 2022. He has a background in Software Sales beginning his career at Oracle before joining Placer.ai which is a startup leveraging ML & AI for mobile location intelligence. Nolan is a graduate of the University of Wisconsin-Madison.

Nolan Fortman
Director of Business Development

MK

MK joined NumFOCUS in July 2024 as the Project Resource Mobilization Lead. With eight years of experience in business development, proposal management, social impact, and nonprofit organizational capacity building, he is excited to contribute to the growing NumFOCUS fundraising team. In addition to his role at NumFOCUS, MK is a certified fitness coach, teaching group fitness in the Washington, DC metro area. He holds a B.A. in Political Science from Sam Houston State University and an M.A. in Sustainable Development, International Policy, and Management from the SIT Graduate Institute.

MK
Project Resource Mobilization Lead

Nicole Foster

Nicole joined NumFOCUS in 2019 as Executive Operations Administrator. Before joining NumFOCUS she worked as an Executive Coordinator and an Administrative Manager. Nicole has a variety of experience, including client services, vendor management, project management, accounting, and legal compliance.

Nicole Foster
Director of Operations

Claudia Alverado

Claudia Alvarado
Operations Coordinator

Addo Davies

Addo Davies
IT DevOps Coordinator

Miriam Mueller

Miriam Mueller joined NumFocus in June 2023 as the Finance Director. Miriam is a 25+ year veteran of nonprofit work, and has worked in nonprofit finance, operations, fundraising, and technology. They are joining NumFocus after two years as a finance and operations director and a decade of owning an accounting firm where they worked with nonprofits and entrepreneurs of all types. Miriam holds a Masters Degree in Medieval History from Columbia University in New York.

Miriam Mueller
Finance Director

Chervonne Rogers

Chervonne Rogers joined NumFOCUS in November 2023 as the Bookkeeper. Chervonne has 20+ years of experience in the accounting field and has worked in different fields within operations, finance and accounting in several industries. Chervonne has a Bachelor of Science in Business Administration with a concentration in Accounting from Regent University in VA and 15+ years of experience directly in bookkeeping. As much as she loves to work, she also loves being a sports mom and a fur-baby mom.

Chervonne Rogers
Bookkeeper

Savannah Simons

Prior to joining NumFOCUS in October 2022, Savannah managed multiple clients for a bookkeeping firm. Savannah has a Bachelor of Science in Business Administration from Eastern Oregon University along with multiple years of bookkeeping experience. Savannah enjoys working with numbers and in her spare she likes to spend time with her dogs.

Savannah Simons
Project Finance Specialist

Lynn Brubaker

​Lynn Brubaker graduated with a Bachelor of Science Business Administration.  Before joining NumFOCUS, she worked at a hedge fund as an Office Manager.

Lynn Brubaker
Project Finance Manager

Arliss Collins

Arliss Collins joined NumFOCUS in 2020 as the Open Source Developer Advocate.  Before joining NumFOCUS she worked as the Data & Metrics Analyst for the Mozilla Foundation as well as the Participation Coordinator for the Mozilla Science Lab.  She brings with her experience in open source advocacy, data science and community engagement. Arliss has a degree in Engineering from Queen’s University, Canada

Arliss Collins
Open Source Developer Advocate

Kari Hall

Kari joined NumFOCUS in 2024 as an Advocacy Coordinator. She has worked in higher education and the non-profit sector for over a decade. Kari graduated from Augustana University with a Bachelor of Arts degree and from Hawai’i Pacific University with a Master of Arts degree. She is a Ph.D. candidate and lives in the beautiful Black Hills of South Dakota. Kari is a lifelong learner and enjoys working with people, research, and data. In her free time she enjoys cooking and exploring the forest with her husband, two boys, and their Irish Setters.
Kari Hall
Advocacy Coordinator

Kamila Stepniowska

Kamila joined NumFOCUS in 2023 as the Projects DEI Coordinator. She has more than decade experience in tech, as entrepreneur, educational programs manager and community builder in Europe and the US. Kamila specialised in AI. In previous years she has been creating B2B, machine learning education programs with deepsense.ai, supporting diversity as COO at Geek Girls Carrots, the Women Who Code Seattle Evangelist, Advisor at She’s Coding, SheWorx Steering Committee members. She brings her experience in DEI, community building and sociology.

Kamila Stepniowska
Projects DEI Coordinator

Kelby Lorenz

Kelby joined NumFOCUS in 2023 as the Digital Marketing Specialist. With nearly a decade of experience behind him in marketing, advertising, PR, and user experience, he is excited to be a part of the NumFOCUS team! In addition to his work here, he also supports his community theatre with their marketing needs, and is a freelance photographer. He has a B.A. in Advertising and Public Relations from Lindenwood University and an M.A. in Communication from Drury University.

Kelby Lorenz
Digital Marketing Specialist

Donovan DelValle

Donovan DelValle (they/them) joined NumFOCUS in 2022 as an Events Intern, and as of 2023 has been hired full-time as the Marketing & Events Coordinator. They received their Bachelor’s in Music Education from New York University in 2021 and have since branched into the events and communications field. They have a background in event planning and working with first-generation students from the Upward Bound program and have aimed to pivot their education and communication skills into a new career in digital marketing, event coordination, and community building.

Donovan DelValle
Marketing Coordinator

Jon Starr

Jonathan joined NumFOCUS in 2023 as Program Manager for the Open-Source Science initiative. He brings experience in science-based open-source projects, science communication and engagement non-profits, and business management and operations. Secondary to NumFOCUS, Jonathan continues to work to enable open science as a core contributor to several open-source projects.

Jon Starr
Program Manager - OSSci

Advisory Council

Matt Greenwood

Matt Greenwood is Chief Innovation Officer and Managing Director at Two Sigma Investments.

Matt Greenwood joined Two Sigma Investments in November 2003. As part of his responsibilities, Matt sets vision and direction for a number of engineering and modeling teams.

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Prior to joining the firm, Matt worked at Entrisphere, Inc. where he served as Lead Developer and Manager for a number of systems on the network element. Prior to that, Matt worked at Bell Labs, in the Operating Systems Group, and for IBM Research, where he was responsible for a number of early efforts in tablet computing and distributed computing. Matt earned a bachelor’s and master’s degrees in mathematics from Oxford University, and a master’s degree in Theoretical Physics from the Weizmann Institute of Science in Israel. Matt also holds a PhD in mathematics from Columbia University, where he taught for a number of years.
Matt Greenwood

Travis Oliphant

Dr. Oliphant has a Ph.D. in Biomedical Engineering from the Mayo Clinic, and M.S. and B.S. degrees in Electrical Engineering (and Math) from Brigham Young University.

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Travis has worked extensively with Python for numerical and scientific programming since 1997, and was the primary developer of the NumPy package and the author of the definitive Guide to NumPy. He is also the primary founding author of the SciPy package. During his academic career, he has worked in the fields of satellite remote sensing, Magnetic Resonance Imaging (MRI), Ultrasound, elastography, and general inverse problems. He was an Assistant Professor of Electrical and Computer Engineering at Brigham Young University from 2001 to 2007 where he taught courses in probability theory, electromagnetics, inverse problems, and signal processing. In addition, he directed the BYU Biomedical Imaging Lab, and performed research on scanning impedance imaging. He has done consulting work since 1997 in laser scattering off of semiconductors, sparse matrix calculations for search engines, and mesh transformations for fluid dynamics. Dr. Oliphant served as President of Enthought from 2007 until 2011, where he oversaw the establishment of additional satellite offices in New York City, Belgium, Cambridge UK, and Mumbai, India. During this time, he worked with Fortune 50 companies such as Shell, J.P. Morgan, and Proctor and Gamble in all aspects of the contractual relationship – from contracts to training to code architecture and code development. He also served on the Board of Directors for Enthought from 2008 until 2011, and during that time, formed strong connections with J.P. Morgan technical leadership staff and other industry leaders.
Travis Oliphant

Gabriela de Queiroz

Gabriela de Queiroz is a Principal Cloud Advocate Manager at Microsoft. She leads and manages the Global AI/ML/Data team in Education Advocacy.

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Previously she was a Program Director working on Open Source, Data & AI Technologies at IBM. She is the founder of AI Inclusive, a global organization that is helping increase the representation and participation of gender minorities in Artificial Intelligence. She is also the founder of R-Ladies, a worldwide organization for promoting diversity in the R community with more than 200 chapters in 55+ countries. She has worked in several startups and where she built teams, developed statistical models, and employed a variety of techniques to derive insights and drive data-centric decisions.

Gabriela de Queiroz

Peter Wang

Peter has been developing commercial scientific computing and visualization software for nearly 20 years. He has extensive experience in software design and development across a broad range of areas, including 3D graphics, geophysics, large data simulation and visualization, financial risk modeling, and medical imaging.

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Peter’s interests in the fundamentals of vector computing and interactive visualization led him to co-found Anaconda (formerly Continuum Analytics). As CTO at Anaconda, Peter leads the open source and community innovation group.

As a creator of the PyData community and conferences, he devotes time and energy to growing the Python data science community and advocating and teaching Python at conferences around the world. Peter holds a BA in Physics from Cornell University.

Peter Wang

Michael Zargham

Dr. Zargham is the founder and Chief Engineer at BlockScience, as well as a core member of the Metagovernance Project. He holds a PhD in Electrical and Systems Engineering from the University of Pennsylvania with a focus on Optimal Dynamic Resource Allocation Policies.

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Zargham has over 15 years of experience designing algorithmic policies in a wide range of domains (including adtech, fintech, and cyberphysical systems). His ongoing focus is optimization and control of socio-technical infrastructures with an emphasis on participatory governance. Zargham’s research focus is on Generalized Dynamical Systems with special attention to systems whose state spaces contain non-numerical data; he is the architect of the open source python package cadCAD (complex adaptive dynamics computer-aided design) and has contributed to SourceCred, Gitcoin, Filecoin, The Graph and many other public protocols. In addition to designing mechanisms at BlockScience, he contributes to the discourse on digital commons with attention to the oversight of algorithms by humans subjected to decisions by those algorithms as part of the Metagovernance Project.

Michael Zargham

Nathan Epstein

Nathan Epstein is a software engineer and data scientist at Holocene Advisors, LP. He works in quantitative investment research following earlier roles at Bloomberg and Wealthsimple. He has published academic research, authored open source software, and delivered talks at various global conferences and meet-ups. 

Nathan Epstein

Amanda Casari

Amanda Casari is a Staff Developer Relations Engineer in Google’s Open Source Programs Office, where she leads the Contributor Experience and Open Source + AI teams.

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She is an engineer and researcher who has worked in many technical disciplines for over 20 years, including developer relations, product management, data science, complexity science, and robotics. Amanda was named an External Faculty member of the Vermont Complex Systems Center in 2021 and co-authored Feature Engineering for Machine Learning Principles and Techniques for Data Scientists for O’Reilly. Her community work includes Open Source Stories, a community-led effort with the goal of making the people of open source and their lived experiences more visible. Amanda is persistently fascinated by complexity, the differences between the systems we aim to create and the ones that emerge, and pie.

Amanda Casari

Jeremy Tanner

Jeremy Tanner’s NumFOCUS / PyData journey started 10 years ago while working at Continuum Analytics (Now Anaconda). After that, more startups; making code review, communication, bare-metal provisioning / management, and secure connection easier. He now works on open source programs at NVIDIA, accelerating Python in the NumFOCUS cinematic universe and beyond.

Jeremy Tanner

Neal Richardson

Neal Richardson is VP of Engineering at Posit and a member of the Apache Software Foundation. He is a maintainer of Apache Arrow, along with many other projects in the R ecosystem. He holds a Ph.D. in Political Science from the University of California, Berkeley.

Neal Richardson

Tim Bonnemann

Tim Bonnemann

Ruben Di Battista

Ruben Di Battista