The idea of the university initially emerged as a form of transmission of knowledge, culture and values. It was later that the purpose of this search for knowledge through research emerged, and it is now impossible to understand the university without this research aspect (Flander et al. 2020). This change came from Humboldt's University idea. He understood the work of a lecturer as a nexus from teaching and research (Paulsson y Macheridis, 2022). Nowadays, higher education has three missions within society. The first one is the education for the labour market insertion through the teaching part, the second one is the research with the aim to build up the life of everyone and the third one is to transfer knowledge to society. It is for this reason why not only do lecturers investigate their own field but also, they have to be able to transmit this knowledge to the society and to their students (Hordósy y Mclean, 2022).

In order to define this union, different perceptions of university faculty staff are found: 1) those who are skeptical of this relationship; 2) those who claim that there is no such union; 3) those who perceive it as a symbiotic relationship, in which research is used as a teaching tool (Tesouro et al., 2014). This is why it is often questioned whether good researchers make good teachers and vice versa (Paulsson and Macheridis, 2022). 

Even though nowadays many universities in Europe follow Humboldt’s idea, there are preferences related to the focus of activity towards teaching or towards research (Paulsson y Macheridis, 2022). These preferences tend to be a function of how organizations evaluate academic work. Part of the problem with this duality might be that teaching is often seen as a secondary task in the academic profession (Lankveld et al., 2017). 

On the other hand, some researchers have analysed the non-relation between these two dimensions, arguing that it is not worth their while to try to transfer what people research to what they teach (Ulla y Tarrayo, 2021). For this reason, some authors have spoken about the barriers in the academic career that prevent the realization of this union. These barriers might be identified as three factors: the first relates to time, dedication and commitment; the second relates to personality characteristics; and the third focuses on the incentives to pursue a career in academia (Pinchado et al., 2019). 

Despite the large number of studies that we find in this regard, there is no clear idea of the benefits that this union can bring to higher education. This is why the aim of this research is to address the concept of a university teaching career by focusing on the link between research and teaching.

In order to respond to the general objective of this study, a systematic review was chosen as the research method. This method is characterized as a process of searching for information by which a rigorous and transparent literature review is carried out, allowing it to be repeated and updated (Newman and Gough, 2020). The information was obtained using the PRISMA method (Urrútia and Bonfill, 2010). The selected documents respond to the following search formula ("teaching" AND "researching") AND "nexus" AND "higher education", and a time limit set from 2015 to the time of the study (April 2022). This research was carried out in three international databases relevant to the topic of study: Web Of Science (WoS), Scopus and Educational Resources Information Center (ERIC). The last phase of the process, which pertains to the complete analysis of the articles, was carried out using an Excel spreadsheet. A content analysis (Flores-Kanter and Medrano, 2019) of the texts was carried out, indicating the year, authors, countries and methodological approach (quantitative, qualitative or mixed), and the information was classified deductively according to the categories that emerged from the bibliographic search. These categories are: arguments in favour, proposals for a nexus, arguments against and barriers to its implementation. A fifth category was also detected inductively, which refers to the demographic differences that influence the conception of this union. The inclusion criteria are: 1)Focusing on linking teaching and research by university faculty staff, 2) Focus on higher education 3) Written in English, Spanish or Catalan 4) Documents published between 2015 and 2022 5) Open access. And the exclusion criteria are: 1) It does not focus on the linking of teaching and research by university faculty staff, 2) focus on other levels of education, 3) Written in other languages, 4) Documents published before 2015, 5) Non-open access.

Despite the fact that the teaching-research nexus has been studied through the years, there is not an agreement of how to make both activities something in common. However, this requires a transformation in the way of understanding the union or even a change of outlook in the institutions or in the agencies that evaluate these professionals (Paulsson and Macheridis, 2022). The consideration of these functions as two connected activities is defended by understanding research as a fundamental point for the search for knowledge, while teaching becomes an essential means for its dissemination (Paulsson and Macheridis, 2022). In this sense, the literature on research-teaching nexus might explore how staff see their different, often divergent and potentially competing roles, or analyses the impact of different curricula and approaches on student outcomes and perceptions. In the same way, the relationship between the two activities makes sense as long as it is understood that the main driving force that links teaching and research is knowledge, so that research builds knowledge and teaching transmits it (Hordósy and Mclean, 2022). This is why the institutions should somehow encourage this union, or even try to connect the subjects taught by the faculty staff with their interest in research, perhaps in this way teaching will be something motivating and not simply a work obligation. For this reason, it could be proposed to use research as a means of teaching by using some methodologies that facilitate this. Thus, it would be necessary to change the faculty staff's thinking about teaching and ways of teaching, so that it is considered from an approach centered on student learning. (Pinchado et al., 2019)

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