We organise various formats of popular science events, which gather between 100 and 800 guests. Some of our team’s members are scientists and engineers, while others are just science geeks and enthusiasts. But we are all volunteers who are passionate about science and believe in Ratio’s mission.

Liubomir Baburov

I have been fascinated by popular science since 2008. My interest in the field was awakened by the books of Richard Feynman and Richard Dawkins, which were also the impetus behind the establishment of the Ratio foundation back in 2012.

Nowadays, I am closely involved with the organisation of the NGO Evolutionary Look Association, and since 2018 I have had the luxury of focusing a bit more on our big events.

Meanwhile, my work experience is in the field of IT product management and business development. Since 2012 I have been serving as manager director of

Vassilena Valchanova

I have been actively exploring my interest in science and critical thinking since 2010. In 2012, I participated in the founding of Ratio. As a member of the NGO, I am in charge of promoting our events, establishing meaningful two-way communication with state and municipal institutions, and working with Ratio sponsors.

Outside of Ratio, I have over 10 years of work experience in the field of communications, marketing and PR. Over that period of time, I have taken on a variety of projects for different companies and participated in the organisation of a series of events with attendance from 100 to over 800 people.

Nikola Kerekov

I have been a part of organising Ratio since 2014. I am in charge of the selection of topics and the communication with speakers for almost all of the organisation’s events. I am also actively participating in programmes for international scientific exchanges, scientific congresses, conferences, and popular science events.

I hold a bachelor's degree in molecular biology and a master's degree in cell biology and pathology. I graduated with honours from Sofia University "St. Kliment Ohridski ”. At the end of 2015, I completed my PhD in immunology at the Institute of Microbiology at the Bulgarian Academy of Sciences.

I have 11 years of experience in research in the field of human autoimmunity, DNA vaccines, and the development of animal models of human diseases.

Petko Zhelyazov

I have been a part of the Ratio team since 2014, and in the last couple of years I have taken on the role of a host and moderator of our events.

I have studied several academic disciplines in the field of humanities and have a master's degree in european studies and international politics. My professional experience is in the field of corporate governance.

Most importantly, however, I am a proud husband, father of two children, and a passionate bibliophile.

Snezhana Yaneva

Since the beginning of 2018, I have been actively engaged with the promotion of the Ratio events and with the financial planning for the NGO. Besides pro-actively seeking new communication platforms, media outlets, and partners to reach audiences, I am also in charge of coordinating our volunteers.

I am in possession of a mathematics degree and a master's degree in finance, which I earned with honours from the University of National and World Economy (UNSS). My work experience is in the field of finance and marketing, and I am currently employed at Telenor as a market research analysts.

I have also had a book review blog in Bulgarian since 2016.

Dimitar Smilyanov

I have been a part of the Ratio organisation since 2015 and at this stage I am in charge of the technical support at our events.

Outside of Ratio, I work as a developer of web platforms and mobile applications, and I have previous experience in computer games development. Since 2017, I have also been a member of the Receipt Bank team.

Over the last 10 years, I have also been actively involved in organising events and volunteering for various organisations—OpenFest, RailsGirls Sofia, Begach.


Dana Tileva

I joined the Ratio team as a graphic designer in 2017. I am involved in the creation of the visual content for our small and big events alike, graphic facilitation during major events, and the production of all the press materials accompanying the work of the big R.

Outside of Ratio, I am a graphic designer at Receipt Bank, a graphic facilitator in 500 Markera, and a freelance designer. I am interested in calligraphy, animation, painting, and everything art related.

You can check out my stuff here

Nevena Niagolova

Since 2018, I have had the honour of doing graphic art for Ratio. I am an artist and designer who has also embarked on the path of architecture. In my work, I use a variety of different techniques and mediums and am constantly striving to learn something new.

Outside of Ratio, I spend my time working as an intern architect at RED Studio and as a freelance graphic and web designer. I also devote time to making art, animation, and games, as well as participating in exhibitions.

My website is and you can also find me on Instagram as @nevcheart.

Kremena Pehlivanova

Since the end of 2018, I help Ratio by eveloping some of our graphic design works. Professionally, I am a UI/UX designer. Over the last few years, I've mostly worked on studying, conceptualizing, prototyping, app usability tests in VR/AR, AI Chatbots and Voice Assistants, as well as mobile apps for iOS and Android. I also teach part time, on the subject of visual communication, as well as design everything from logos to book covers as a freelance designer.

Desislava Ivanova

I joined the design team in 2019. For a while, I worked as a graphic designer and recently I've started working on UI/UX.

I love travelling, learning about new cultures. I am also passionate about photography, fantasy, board games and cuisine.