Teaching mathematics in informal settings is a relatively new phenomenon, but it has gained more attention due to the recent changes in the society. The aim of the present quantitative study was to compare the learning outcomes of Latvian and Swedish 12-year-olds when they visited a science centre mathematics-art exhibition originally designed in Estonia. The results showed that in general, prior knowledge of the exhibition contents was the strongest predictor of post-test results in both countries but that mathematical thinking skills and self-concept had a small added value in explaining the post-test results. The results of the study give some of the first pieces of evidence of the effectiveness of out-of-school mathematics teaching in a science exhibition context, providing a good basis for further studies.

For decades, particle physicists have been using open access archives of preprints, i.e. research papers shared before the submission to peer reviewed journals. With the shift to digital archives, this model has proved to be attractive to other disciplines: but can it be exported? In particle physics, archives do not only represent the medium of choice for the circulation of scientific knowledge, but they are central places to build a sense of belonging and to define one's role within the community.

Open Science may become the next scientific revolution, but still lingers in a pre-paradigmatic phase, characterised by the lack of established definitions and domains. Certainly, Open Science requires a new vision of the way to produce and share scientific knowledge, as well as new skills. Therefore, education plays a crucial role in supporting this cultural change along the path of science. This is the basic principle inspiring the collection of essays published in this issue of JCOM, which deals with many subjects ranging from open access to the public engagement in scientific research, from open data to the social function of preprint servers for the physicians' community. These are issues that go along with the targets of the FOSTER project (Facilitate Open Science Training for European Research) funded by the European Union, which has provided interesting food for thought in order to write this commentary.

The design, delivery and evaluation of JCOM Masterclasses has given us the opportunity to reflect on the audiences, training needs and training schemes available to people working at different levels and in different contexts to communicate STEM subjects to a diverse variety of people. Although not always widely available, short courses in the communication of science have been offered in a number of countries around the world over the past few years. We felt it is now time to open a discussion on the rationale, the methods and the objectives of such training programmes.

During the last decade universities have developed policies and infrastructures to support open access to publications but now it is time to move a step forward. There is an increasing demand for accessing data supporting the research results to validate and reproduce them. Therefore universities have to be prepared for this new challenge that goes beyond dissemination because it requires a strategy for managing research data within institutions. In this paper I will try to give some hints on how to deal with this challenge that can be framed in the new open science movement aimed at providing openness in all the whole cycle of research.

When entering the research world, Early Career Researchers (ECRs) may encounter difficulties building a good reputation for their research, its quality and the research results. Open access is the movement that could assist ECRs to: (a) widely disseminate their scholarly outputs, (b) demonstrate the research and societal impact of their work and, (c) organise online research portfolios that can be accessed by all researchers, as well as prospective employers.

This study addresses an open question about science bloggers' self-perceived roles as science communicators. Previous research has investigated the roles science journalists see themselves engaging in, but such research has failed to capture the experiences of science bloggers as a broad and diverse group that is yet often very different in their practices from professional journalists. In this study, a survey of over 600 science bloggers reveals that on the broadest level, science bloggers see themselves engaging most often as explainers of science and public intellectuals. Perceived communication role depends predominantly on occupation, science communication training, blog affiliation and gender.

The ever-changing nature of academic science communication discourse can make it challenging for those not intimately associated with the field ― scientists and science-communication practitioners or new-comers to the field such as graduate students ― to keep up with the research. This collection of articles provides a comprehensive overview of the subject and serves as a thorough reference book for students and practitioners of science communication.