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Ariella Riva Ritvo-Slifka, President
Ariella Riva Ritvo-Slifka, PhD


Dr. Ariella Riva Ritvo-Slifka is Alan Slifka’s widow and a philanthropist in her own right. Alan was her life partner, mentor, closest friend and beloved husband. Their visions aligned closely and they complemented one another as they worked, alongside their board and staff, to heal the world.

Dr. Ritvo-Slifka has been the president of the Alan B. Slifka Foundation since 2007 and its chairwoman since 2011. She has been active in biomedical, coexistence and Jewish philanthropic organizations for over 20 years. Dr. Ritvo-Slifka’s professional background is in autism research, clinical practice and teaching. She is an assistant clinical professor at the Child Study Center at Yale University School of Medicine.

Her rigorous scientific background and emphasis on data-oriented results, coupled with Mr. Slifka’s vision, were instrumental in fostering the Foundation’s strategic approach to its mission.

 Sarah Silver, Executive Director Sarah Silver

Executive Director

Sarah Silver is a social-change professional who designs, executes and manages strategies and initiatives for mission-driven organizations. The Foundation’s executive director since 2002, Sarah shares its commitment to inclusive, shared societies. Sarah brought to the Foundation two decades of experience in journalism, public policy and civil society. She was a news documentary producer for Peter Jennings Reports and ABC News Productions and one of her documentaries received an honorable mention at the Banff Film Festival. She served as press secretary to U.S. Congressman Mike Synar (D-OK); associate director for media relations at the Natural Resources Defense Council; and, press secretary for the Committee to Protect Journalists. Sarah developed and delivered a curriculum on media relations training to civil society organizations in the emerging democracies of the former Soviet Union. The media relations manual she wrote for the project has been translated into thirty languages. She has served on the board of American Forests, the Jewish Women’s Fund of Colorado and several committees of her local Sierra Club.

 Rachel Markowitz, Chief Financial Officer Rachelle Markowitz

Chief Financial Officer

Rachelle Markowitz is the Chief Financial Officer of the Alan B. Slifka Foundation and serves as the foundation’s treasurer.  A dear friend of the Slifka family, Rachelle has worked in the Slifka Family Office for 15 years.  She oversees the foundation’s finance, accounting, banking, and investment functions and is also in charge of human resources, benefits, and facilities. Rachelle feels fortunate to work for a private charitable foundation where she is able to partner her financial skills with her desire to do tikkun olam – trying to make the world we live in a better place.  

 Allison Sole, Program Officer Allison Sole

Director of Biomedical Programs

Allison brings nearly 15 years of experience in the philanthropic sector to her role at the Alan B. Slifka Foundation, where she is director of biomedical programs with a current focus on sarcoma. Prior to completing a yearlong project at Google, Allison served as inaugural deputy director of 21/64, a division of the Andrea and Charles Bronfman Philanthropies specializing in intergenerational family philanthropy.  There she consulted and presented to family foundations and related entities and developed original resources to facilitate philanthropic conversations. Her interest and commitment to the next generation began when she was a psychoeducational counselor for youth. She parlayed this interest to the Arnold P. Gold Foundation for Humanism in Medicine, a public philanthropy dedicated to instilling the value of patient-centered care in doctors-in-training and where she was a Programs Director. She is thrilled to be back working among a community of dedicated medical researchers and practitioners, those seeking a cure for bone and soft-tissue sarcomas.

 Michal Strisover, Program Officer Michal Strisover

Program Officer, Israel

Michal has been with the Slifka Foundation since 2004. She has worked both in the US office and in Israel and currently serves as the Israel Program Officer. Michal brings to her work expertise in international relations and peace and development studies.  She lives in Modi'in, Israel with her husband David and their three children.

 Sharon LeWinter, Executive Assistant Sharon LeWinter

Executive Assistant to Riva Ariella Ritvo-Slifka and the Alan B. Slifka Foundation

Sharon LeWinter is the Executive Assistant at the Alan B. Slifka Foundation. Prior to joining the Slifka Foundation, Sharon was Executive Assistant to the Chief Executive Officer, as well as the Chief Services Officer of JASA (Jewish Association for Services for the Aged). Before that she worked at UJA-Federation of New York. Her roles there encompassed support for the Senior Vice President for Fundraising, and assistant to the Executive Director of Philanthropy Advisors, a consulting arm for family foundations. Sharon’s introduction to philanthropy began at the Ciba Educational Foundation which merged into the Novartis US Foundation, a philanthropic arm of Novartis Corporation, a pharmaceuticals firm.

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