Abstract
In the last decades, the assurance of doctoral education's quality and their respective external quality assurance (QA) systems have been on the agenda of many European countries. Portugal is no exception, with doctoral education being envisaged by the national study programmes' accreditation system. This study aims to discuss both the forms assumed by the QA of doctoral education within the scope of a tightly regulated system, such as the Portuguese one, as well as the effects or impact of such a system in this education level. In trying to explore this impact, particular attention is given to the accreditation results (full accreditation, conditional accreditation and non-accreditation) of the doctoral programmes according to their scientific area and higher education sector (public and private). Overall it is possible to conclude that the Portuguese QA system has been contributing to the reorganisation of doctoral education, both by excluding programmes that do not meet a set of minimum quality criteria and by promoting the enhancement of the remaining programmes, through the enforcement of improvement measures. This reorganisation seems to differently affect doctoral programmes from distinct scientific areas as well as from private and public institutions.

Abstract
Although companies seek to export in order to meet the growing importance of international markets, vis-à-vis domestic markets, this chapter presents a case study of a company founded by two former high school teachers who started a beverage company in 2015 and quickly reached an early internationalization. The company produces alcoholic beverages and has won international awards regarding the quality of its product, which has given it an important status and opened the door to a process of rapid internationalization. This will be used to explore the theory of entrepreneurship and how two potential entrepreneurs, with employment difficulties in teaching, began with a project that gave birth to a born global firm.

Abstract
One of the current trends in the luxury market is the development of offers targeted to the millennial generation. In fact, this generation is seen as a potentiator of market growth, considering that the future of the luxury sector will depend on the capacity to reach this generation. This topic is particularly relevant for the marketing area, namely for the tourism sector. Another of the major trends for the tourism sector is the sustainability issue, with an emphasis on ecotourism. In this work we discuss the main contributions of the literature that allow to interlink the domains of luxury marketing, millennial generation, and ecotourism, proposing a set of hypotheses for future research. © 2019 AISTI.

Abstract
Some coronagraph masks can be turned into wave front sensing masks thanks to minor modification. For instance, one only has to divide by two the depth of the central well to convert the Roddier & Roddier coronograph into the Zernike wave front sensor (WFS). Physically, the opposition of phase in coronagrapy becomes a quadrature phase in wave front sensing. Here, we replicate this idea to the Four Quadrant Phase Mask (FQPM) coronagraph by introducing a sensor that we call the iQuad WFS, generated by a mask which has the same geometrical structure as the FQPM but with a modified differential piston. An optical and mathematical description of this new WFS is firstly provided showing its great elegance and the central role played by the Hilbert transform in its understanding. We then compare its performance criteria with two classical wave front sensors. We finally show the iQuad sensor has major similarities to the Pyramid sensor making it a wonderful theoretical object to improve our understanding of this sensor.

Abstract
We propose an adaptive secrecy scheme using polar codes with random frozen bits for a general wiretap channel, in which to protect the data from a potential eavesdropper, part or all of the frozen bits are randomly generated per message. To assess the secrecy level of the proposed scheme, three types of decoding strategies are evaluated: a matching decoder which knows the positions of all inserted bits inside the blocklength and tries to estimate them using the same decoding techniques, a blind decoder which treats all the frozen bits as the same value, and a random decoder which considers those dynamic bits as random at the receiver. Results are presented in terms of the system security gap, assuming an adaptive decoding strategy. It is shown that the system achieves combined secrecy and reliability. The proposed scheme does not assume knowledge of the eavesdropper's channel when defining the indices of information and frozen bits.

Abstract
Market cooperation in the electrical sector is crucial for competitiveness improvement. In the particular case of ancillary services, it was only carried out within a national context until the recent past. In the Iberian case, since the middle of 2014, a bilateral mechanism has allowed tertiary reserve sharing between the Portuguese and the Spanish Transmission System Operators (TSOs). This mechanism generates gains for the Portuguese electrical system. However, with a high level of cooperation, these gains could be improved. The Portuguese TSO is one of the most peripheral TSOs in Europe and, as such, it considerably benefits from market integration, in the various dimensions of the electrical sector. Hence, as a new contribution to earlier studies, this paper evaluates, from the Portuguese strategic perspective, what would happen to revenues when sharing replacement reserves without any restriction, considering a full integration of Europe's southwest countries in contrast to the traditional bilateral solution that is currently in place. The new methodology used in this paper is a cross-comparative evaluation between different bilateral combinations of TSOs' offers. A comprehensive study is presented and conclusions are duly drawn.