Abstract
New media and social network sites (SNSs) currently play an important role in our society and in our daily practices (Boyd and Ellison 2008; Lister et al 2009; Watkins 2009; Papacharissi 2011). This necessarily affects the way we learn together, as explored in research spanning several areas. Regarding higher education, Facebook has an increasingly prominent position and is more widely investigated as an instructional tool in the college classroom than most SNSs (Tess 2013). From the perspective of teaching and learning, the Web 2.0 is seen as an enabler of a vision in which the student will find information potentially contradicting the knowledge acquired through the traditional formal learning process (Santos 2009). This feature leads to a continuous discussion of the facts, topics and subjects having an awareness of a common range of formal established knowledge shared in a given community and, at the same time, the joint reflection and debate within this same community. This new reality, in which the roles of the teacher and the student (or the roles of who teaches and who learns) become fuzzy, difficult to distinguish clearly, also brings the need for new ways to understand, describe, and explain the learning process and the ways in which it develops. In this paper we use the concept of social e-learning (Martins et al. 2012), building on the connectivist perspective (Siemens 2004, 2006, 2008). Social e-learning can be considered as a learning process whereby the Internet represents a space for participation, sharing, and collaboration, with new opportunities to create, share content, and interact with others (Bennett 2012) - an open door to build more open and flexible knowledge, where students build and rebuild their own path. A concrete format for its implementation is proposed and a genuine experience is presented and discussed. The social e-learning model presented in this article has been successfully applied in a training course in the field of business communication, held by Citeforma. Citeforma is a Portuguese vocational training centre, jointly managed by SITESE (a services workers and technicians union) and IEFP (the Portuguese Institute for Employment and Vocational Training).

Abstract

Abstract
In this paper, an agent-based model is proposed to improve market efficiency by using different Demand Response Programs (DRPs) in the day-ahead electricity market. To this end, both incentive-based and price-based DRPs are considered. On this basis, time of use, real time pricing, emergency demand response program, interruptible/curtailable services and critical peak pricing are investigated. The tariffs of the considered price-based programs and the amount of incentive in the incentive-based programs are optimized through the proposed model. Furthermore, a market power index, i.e., Share Weighted Average Lerner Index (SWALI) and the operation cost are used to evaluate the market efficiency and the market power. The proposed model optimizes the DRPs to improve the electricity market efficiency by using a multi-attribute decision-making approach. The results show that the market operator can mitigate the potential occurrence of market power in a power system by finding the optimal DRP.

Abstract
We propose and apply two methods for estimating phase discontinuities for two realistic scenarios on VLT and Keck. The methods use both phase diversity and a form of image sharpening. For the case of VLT, we simulate the 'low wind effect' (LWE) which is responsible for focal plane errors in low wind and good seeing conditions. We successfully estimate the LWE using both methods, and show that using both methods both independently and together yields promising results. We also show the use of single image phase diversity in the LWE estimation, and show that it too yields promising results. Finally, we simulate segmented piston effects on Keck/NIRC2 images and successfully recover the induced phase errors using single image phase diversity. We also show that on Keck we can estimate both the segmented piston errors and any Zernike modes affiliated with the non-common path.

Abstract

Abstract
An ungravity-inspired model is employed to examine the astrophysical parameters of white dwarf stars (WDs) using polytropic and degenerate gas approaches. Based on the observed properties such as mass, radius, and luminosity of selected WDs, namely, Sirius B and epsilon Reticulum, bounds on the characteristic length and scaling dimension of the ungravity (UG) model are estimated. The UG effect on the Chandrasekhar limit for WDs is shown. The UG model is examined in the study of ultramassive WDs, e.g., EUVE J1746-706. The UG-inspired model implies that a new location for some WDs on the Hertzsprung-Russell diagram is found.