Abstract
In this paper it is presented a usability evaluation of an entertainment platform, well-known, YouTube. The main aim is to study how people with intellectual disabilities interact with the layout and uses their search field option. We intended to observe and analyze performance and satisfaction but also if the interface can give them autonomy on the search option. The results show that participants had a good experience with the interface, however cannot be autonomy with the search option.

Abstract
This paper presents a study on the evolution of digital skills of a group of people with intellectual disabilities, when performing tasks such as painting, making puzzles, playing games, or word search. For the effect, we compare results in two assessment moments: in the first one, the group with intellectual disabilities had little or no experience as regards as performing universal tasks (selection, manipulation and navigation) and with the Web; in the second one, the group had some experience obtained within the 6 months after the first assessment moment. We aimed at evaluating the evolution of their digital skills by comparing the two assessment moments through the following usability variables: successful conclusion of activities, type of difficulties found, errors, satisfaction, motivation and autonomy indicators. The results revealed that participants showed learning skills when performing all the three universal tasks (namely: selection, manipulation and navigation) which is indicated by the number of participants that was able to conclude the activities, also confirmed by the prominent results of the second assessment moment. When it comes to errors, they made more errors in the first assessment moment, in general. When handling the input devices the participants had a better performance with the mouse than the keyboard. On the other hand, they improved their keyboard handling. However, it was observed that it is not a device that they can be autonomous with due to their reading/writing difficulties, which itself represents a didactic challenge when it comes to the very presentation of appropriate methodologies and techniques that may help them overcome such problem.

Abstract
This is the first research that aim to analyze the practice of Sexting in Portugal. The goals of this study included comparing the differences between the Sexting dimensions and independent factors (gender, age, literacy qualifications, profession, residence, marital status, existence of a stable relationship, most used media, place of frequent use of the media, most commonly used technological device, security perception of communication technology, number of text messages sent per day, recipients of text messages) and corroborating the existence of correlations between the Sexting dimensions. The study sample consisted of 301 individuals aged between 18 and 52 years (158 adults and 143 young adults) and included both females (169) and males (132). The instruments used included a translated and adapted version of the Sex and Tech Survey, created by The National Campaign to Prevent Teen and Unplanned Pregnancy, and the elaboration of 7 social and demographic questions and 6 questions about media consumption and daily technology use. The results showed that environment exposure was higher in males as well as in the group of individuals of both sexes who sent approximately 76-90 written messages per day. By contrast, positive emotions and the development of greater interest in Sexting were higher in women. Positive emotions were higher in young adults, students of both sexes and unemployed persons.

Abstract
There is a trend towards the use of Virtual Reality (VR) environments and its evolution has promoted new interaction approaches so there is a need for studying a number of factors that can have impact on its usability. This paper studies the impact of the body position on the usability of VR environments. For the effect, a case study was undertaken based on a bicycle ride that considers two body positions: riding the bicycle seated with the feet on the pedals and hands in the handlebar; and standing with the feet on the ground and the hands on the handlebar. On both cases they had control over the bicycle (steer and brakes). These two body positions were considered as they will allow studying in detail the impact of the different body positions: the first condition mimics the real body position of the depicted scenario while the second condition tests an alternate body position. Results regarding the system's effectiveness have shown an 100% success rate as all participants concluded the task successfully and there were no dropouts. The efficiency results have revealed that the more the participants used the VE the less the number of errors they made and that the completion time differences between the tested conditions were insignificant (> 0.5 seconds). As for satisfaction, participants reported a preference towards the standing position. Furthermore, results reveal that body position has impact on the users' performance but it does not necessarily affect their satisfaction over the virtual experience. © 2016 ACM.

Abstract
Equipment such as head-mounted displays are now available for the average consumer at affordable prices. This promotes the usage of this equipment for content consumption and demonstrations, thus it becomes important to establish the best practices for using this technology, namely guidelines in what concerns the recommended exposure time. Therefore, the purpose of this work is to study the impact of the exposure time on the feeling of presence while watching 360 degrees video using an head-mounted display. The independent variables of the study are the exposure time to the stimuli and gender of participants. There were tested four different exposure times: 1 minute, 3 minutes, 5 minutes and 7 minutes. For measuring presence, it was a Portuguese version of the Igroup Presence Questionnaire (IPQ) which considers also 3 presence subscales: spatial presence, realism and involvement. The results have revealed that there are few statistically significant differences for the given exposure times at the level of the sense of presence, apart from spatial presence and realism subscales, which consistently increased with exposure time for male participants and slightly decreased for female ones. Men always needed longer exposure times (> 1 minute) to report the highest scores, while women had the opposite behaviour, frequently reporting maximum scores for the shortest experiences.

Abstract
Novel input modalities such as touch, tangibles or gestures try to exploit human's innate skills rather than imposing new learning processes. However, no work has been reported that systematically evaluates how these interfaces influence users' performance, that is, assesses if one interface can be more or less appropriate for interaction regarding: (1) different age groups; and (2) different basic tasks, as content insertion or manipulation. This work presents itself as an exploratory evaluation about whether or not the users' efficiency is indeed influenced by different input modalities and age. We conducted a usability evaluation with 60 subjects to understand how different interfaces may influence the speed and accuracy of three specific age groups (children, young adults and older-adults) when dealing with a basic content insertion task. Four input modalities were considered to perform the task (keyboard, touch, tangibles and gestures) and the methodology was based on usability testing (speed, accuracy and user preference). Overall, results show that there is a statistically significant difference in speed of task completion between the age groups, and there may be indications that the type of interface that is used can indeed influence efficiency in insertion tasks, and not so much other factors like age. Also, the study raises new issues regarding the "old" mouse input versus the "new" input modalities. © 2016 ACM.