Virtual social network-mediated English language learning in a Saudi tertiary EFL context : innovation and agency : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Applied Linguistics at Massey University, Palmerston North, New Zealand

The study explores the nature and roles of virtual social network (VSN) within a Saudi tertiary EFL (English as a foreign language) context, and the trajectory of the students’ experiences and perceptions of Twitter inside the classroom and of WhatsApp outside the classroom throughout a 12-week semester. The study draws on the three broad phases of Fullan’s change process (Fullan, 2001, 2007, 2016) for its underpinning theoretical framework and utilizes agency theory (van Lier, 2004, 2008, 2010) as an analytical tool for developing a deep understanding of the ways the innovative use of a VSN can aid students in and outside the classroom by allowing them to practice and collaborate in English learning. The study utilizes a mixed methods approach for data collection, divided into two stages; one designed to gather background information and another for a longitudinal study. The data collection instruments employed for the background stage included a questionnaire, interviews, and classroom scenarios, to gather data from 93 English language teacher trainees and 84 Preparatory Year Program (PYP) students from three different colleges at Qassim University (QU) in Saudi Arabia. The data collection instruments for the longitudinal study stage, which consisted of initial and post-project interviews, focus group participation, research log observations in and outside the classroom, and a post-project questionnaire, were employed to gather data from 25 PYP students throughout the 12-week semester. The study results revealed that VSN in the Saudi EFL context is divided into two types, private- and public-based, and that participants’ use and activity in each type varies depending on the platform affordances. It also suggests that, while students may have a positive attitude toward the use of a VSN in their daily lives, contextual constraints could mean that classroom use may fail to be sustained over a relatively long period of time. Within the study, although Twitter’s affordances in terms of anonymity and perceived newness initially motivated the students to exercise their agency in English learning, their anxiety, the teacher’s role, and the university infrastructure all played a crucial role in the failure of Twitter’s use to be sustained inside the classroom beyond the ninth week. However, WhatsApp’s implementation exhibited its sustainability by continuing even after the study ended and until the end of the semester. WhatsApp allowed the students to collaborate, practice what they were learning, develop autonomy, and transit from being passive to active learners, not only in English but also in other subjects. Finally, this thesis concludes by illustrating the value of interpreting the complex and dynamic nature of the innovation’s implementation process using agency theory from an ecological perspective. It also recommends ways in which teachers could implement VSN in the language classroom

Variational Optimal-Control Problems with Delayed Arguments on Time Scales

This article deals with variational optimal-control problems on time scales in the presence of delay in the state variables. The problem is considered on a time scale unifying the discrete, the continuous and the quantum cases. Two examples in the discrete and quantum cases are analyzed to illustrate our results.Comment: To apear in Advances in Difference Equation

Study and interpretation of the millimeter-wave spectrum of Venus

The effects of the Venus atmospheric constituents on its millimeter wavelength emission are investigated. Specifically, this research describes the methodology and the results of laboratory measurements which are used to calculate the opacity of some of the major absorbers in the Venus atmosphere. The pressure broadened absorption of gaseous SO2/CO2 and gaseous H2SO4/CO2 has been measured at millimeter wavelengths. We have also developed new formalisms for computing the absorptivities of these gases based on our laboratory work. The complex dielectric constant of liquid sulfuric acid has been measured and the expected opacity from the liquid sulfuric acid cloud layer found in the atmosphere of Venus has been evaluated. The partial pressure of gaseous H2SO4 has been measured which results in a more accurate estimate of the dissociation factor of H2SO4. A radiative transfer model has been developed in order to understand how each atmospheric constituent affects the millimeter wave emissions from Venus. Our results from the radiative transfer model are compared with recent observations of the micro-wave and millimeter wave emissions from Venus. Our main conclusion from this work is that gaseous H2SO4 is the most likely cause of the variation in the observed emission from Venus at 112 GHz

Understanding the variation in the millimeter-wave emission of Venus

Recent observations of the millimeter-wave emission from Venus at 112 GHz (2.6 mm) have shown significant variations in the continuum flux emission that may be attributed to the variability in the abundances of absorbing constituents in the Venus atmosphere. Such constituents include gaseous H2SO4, SO2, and liquid sulfuric acid (cloud condensates). Recently, Fahd and Steffes have shown that the effects of liquid H, SO4, and gaseous SO2 cannot completely account for this measured variability in the millimeter-wave emission of Venus. Thus, it is necessary to study the effect of gaseous H2SO4 on the millimeter-wave emission of Venus. This requires knowledge of the millimeter-wavelength (MMW) opacity of gaseous H2SO4, which unfortunately has never been determined for Venus-like conditions. We have measured the opacity of gaseous H2SO4 in a CO2 atmosphere at 550, 570, and 590 K, at 1 and 2 atm total pressure, and at a frequency of 94.1 GHz. Our results, in addition to previous centimeter-wavelength results are used to verify a modeling formalism for calculating the expected opacity of this gaseous mixture at other frequencies. This formalism is incorporated into a radiative transfer model to study the effect of gaseous H2SO4 on the MMW emission of Venus