Abstract
There are a vast number of studies on the relationship between R&D and exports. However, the results are not always clear-cut. This study evaluates whether, in the case of a small, open and peripheral country in which exports are the engine of economic growth despite a noticeable laggardness in terms of R&D, the firms' R&D impacts on and/or is influenced by their exports, as well as whether the interrelation between R&D and exports impacts on the performance of firms. Using an unique dataset comprising all (more than 340 thousands) non-financial companies based in Portugal, over the period 2006-2012, estimations based on bivariate probit models, which provide the simultaneous estimation of the two decisions (R&D and exports), taking into account the correlation between the estimation errors of the equations for R&D and exports, confirm there is complementarity between R&D and exports, which means that engaging in R&D activities will increase the firm's probability of engaging in export activities. Additionally, engaging in export activities will also increase the probability of engaging in R&D. The results also provide support for the hypothesis that more productive firms self-select into exporting activities and also provide support for the learning-by-exporting hypothesis. Finally, based on a panel model we further found that R&D and exports have a positive effect on sales growth, which is enhanced when both activities occur simultaneously.

Abstract
Entrepreneurship has become a dynamic field of research in the last two decades. However, rural entrepreneurship' has been largely overlooked. It seems therefore timely to present a quantitative survey of the literature in this particular area. Based on 181 articles on rural entrepreneurship published in journals indexed in Scopus, we found that rural entrepreneurship is an essentially European concern, whose most prolific authors are affiliated with institutions in the UK and Spain. Organisational characteristics, policy measures and institutional frameworks and governance have attracted considerable attention in recent years, being considered emergent topics of research. In contrast, theory building has not attracted much research over the period in analysis, which suggests that the theoretical body of rural entrepreneurship is still incipient, hindering the establishment of its boundaries and of a suitable research agenda. Empirical literature on rural entrepreneurship has focused mainly on developed countries, most notably, the UK, the USA, Spain, Finland and Greece. Given the potential rural entrepreneurship represents for less developed and underdeveloped countries, more research on the topic targeting these countries is an imperative.

Abstract
The empirical literature focusing mainly on the USA suggests that class absenteeism undermines students' academic performance and that an enforced mandatory attendance policy may be beneficial. Based on a different cultural and economic context, and using data on 146 second-year management students enrolled in a macroeconomics course at an elite economics school in Portugal, it is shown that even when controlling for potential endogenous factors associated with attendance and academic performance, absenteeism considerably lowers the students' final grade (about 2 points in a 0-20-point grading scheme). In addition, it is established that a compulsory, though flexible, attendance policy contributes to improving students' academic performance.

Abstract
Although a myriad of important theoretical and empirical contributions on ageing populations exist, these are diffuse and lack an integrated vision of the distinct mechanisms through which ageing populations affect economic growth. This being the case, in this paper we survey the literature that provides insights regarding the ageing population and its effect on economic growth. In particular, we seek to uncover the main mechanisms by which ageing affects economic growth.

Abstract
Human capital is identified as one of the main determinants of economic growth and plays an important role in the technological progress of countries. Nevertheless, existing studies have to some extent neglected the importance of human capital in the growth process via the interaction it can have with a country's industrial specialization. Additionally, the emphasis is mainly placed on supply-side determinants, while demand-side factors are neglected, particularly the relevance of the processes of structural change. Thus, using a growth model which integrates variables from both the supply side and demand side, we assess the direct and indirect effects of human capital on economic growth, including in the latter the interaction of human capital with the industrial specialization of countries. Based on dynamic panel data estimations, we found that human capital and the countries' productive specialization dynamics are crucial factors for economic growth. Moreover, the interaction between human capital and structural change in high knowledge-intensive industries impacts significantly on economic growth. However, the sign of this effect depends on the type of country and the period of analysis. Specifically, over a longer time span (1960-2011) and for more highly developed (OECD) countries, the impact of the interaction between human capital and structural change is positive. When we also include transition and Mediterranean countries over a shorter time period (1990-2011), we find that human capital significantly and positively impacts on the countries' economic growth but the effect of human capital via specialization in high-tech and knowledge-intensive activities is negative. The latter result indicates that the lack of industrial structures able to properly integrate highly educated individuals into the productive system leads countries to experience disappointing economic returns.

Abstract
The commercialization of research done by universities and research institutes is seen as a key element of entrepreneurship, justifying a better understanding of the entrepreneurial process within those institutions. Despite efforts in recent decades, there remains a widespread ignorance about who are the individuals with a greater vocation for research and marketing of knowledge. Focusing on a relatively unexplored context - the field of life sciences in a moderate innovator country, Portugal - this study adds new empirical evidence to the precedents of academic entrepreneurship. The results, based on 247 responses, evidence that entrepreneurship (including patent production, consultancy work and creation of start-up companies) is still very incipient. The econometric analysis of the "Index of entrepreneurial activity," shows that: (1) the phenomenon of academic entrepreneurship is within everyone's reach, but embraced by very few; and (2) academic entrepreneurship feeds on the exchange of knowledge and resources among universities and research institutes and their socio-economic environment. Thus, to increase academic entrepreneurship in life science in Portugal, the mechanisms to facilitate the interactions between universities and the business community must be strengthened, promoting the development of business clusters with the integration of the academic world, which will enable the transformation of knowledge into market products and services.