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

Critical behavior of CrTe1-xSbx ferromagnet

The modified Arrott plots and Kouvel${\text -}$Fisher analysis are used to investigate the critical behavior of $CrTe_{1-x}Sb_{x}$ ferromagnetic material near its transition temperature $T_{c}$. The Ferro${\text -}$Paramagnetic transition is found to be a second${\text -}$order phase transition. For $x=0.2$, the critical exponents closely follow the Mean Field Model with the estimated values of the exponents: $\beta$ =0.60 $\pm$ 0.03, $\gamma$ =1.00 $\pm$ 0.03 and $\delta$ =2.67 $\pm$ 0.03. We also found with increasing Sb${\text -}$concentrations, the critical exponents significantly deviate from the mean field values and gradually shift towards the 3${\text -}$Dimensional behavior. The deviation may indicate changes in the spin configuration with increasing Sb concentrations

Selfconsistent hybridization expansions for static properties of the Anderson impurity model

By means of a projector-operator formalism we derive an approximation based on a self consistent hybridization expansion to study the ground state properties of the Anderson Impurity model. We applied the approximation to the general case of finite Coulomb repulsion $U$, extending previous work with the same formalism in the infinite-$U$ case. The treatment provides a very accurate calculation of the ground state energy and their related zero temperature properties in the case in which $U$ is large enough, but still finite, as compared with the rest of energy scales involved in the model. The results for the valence of the impurity are compared with exact results that we obtain from equations derived using the Bethe ansatz and with a perturbative approach. The magnetization and magnetic susceptibility is also compared with Bethe ansatz results. In order to do this comparison, we also show how to regularize the Bethe ansatz integral equations necessary to calculate the impurity valence, for arbitrary values of the parameters.Comment: 8 pages, 5 figure

A new integrable problem with a quartic integral in the dynamics of a rigid body

We consider the problem of motion of a rigid body about a fixed point under the action of an axisymmetric combination of potential and gyroscopic forces. We introduce a new integrable case, valid on zero level of the cyclic integral, that generalizes the known case of motion of a body in liquid due to Chaplygin and its subsequent generalization by Yehia. Apart from certain singular potential terms, the new case involves finite potential and gyroscopic forces, which admit physical interpretation as resulting from interaction of mass, magnetized parts and electric charges on the body with gravitational, electric and magnetic fields.Comment: This work will appear shortly in "Journal of Physics A: Mathematical and Theoretical

Effects of semiclassical spiral fluctuations on hole dynamics

We investigate the dynamics of a single hole coupled to the spiral fluctuations related to the magnetic ground states of the antiferromagnetic J_1-J_2-J_3 Heisenberg model on a square lattice. Using exact diagonalization on finite size clusters and the self consistent Born approximation in the thermodynamic limit we find, as a general feature, a strong reduction of the quasiparticle weight along the spiral phases of the magnetic phase diagram. For an important region of the Brillouin Zone the hole spectral functions are completely incoherent, whereas at low energies the spectral weight is redistributed on several irregular peaks. We find a characteristic value of the spiral pitch, Q=(0.7,0.7)\pi, for which the available phase space for hole scattering is maximum. We argue that this behavior is due to the non trivial interference of the magnon assisted and the free hopping mechanism for hole motion, characteristic of a hole coupled to semiclassical spiral fluctuations.Comment: 6 pages, 5 figure

Cl electrosorption on Ag(100): Lateral interactions and electrosorption valency from comparison of Monte Carlo simulations with chronocoulometry experiments

We present Monte Carlo Simulations using an equilibrium lattice-gas model for the electrosorption of Cl on Ag(100) single-crystal surfaces. Fitting the simulated isotherms to chronocoulometry experiments, we extract parameters such as the electrosorption valency gamma and the next-nearest-neighbor lateral interaction energy phi_nnn. Both coverage-dependent and coverage independent gamma were previously studied assuming a constant phi_nnn [I. Abou Hamad, Th. Wandlowski, G. Brown, P.A. Rikvold, J. Electroanal. Chem. 554-555 (2003) 211]. Here, a self-consistent, entirely electrostatic picture of the lateral interactions with a coverage-dependent phi_nnn is developed, and a relationship between phi_nnn and gamma is investigated for Cl on Ag(100).Comment: Accepted for publication in Electrochimica Acta, 10 pages, 7 figures, 2 tables and an appendi

Spin polaron in the J1-J2 Heisenberg model

We have studied the validity of the spin polaron picture in the frustrated J1-J2 Heisenberg model. For this purpose, we have computed the hole spectral functions for the Neel, collinear, and disordered phases of this model, by means of the self-consistent Born approximation and Lanczos exact diagonalization on finite-size clusters. We have found that the spin polaron quasiparticle excitation is always well defined for the magnetically ordered Neel and collinear phases, even in the vicinity of the magnetic quantum critical points, where the local magnetization vanishes. As a general feature, the effect of frustration is to increase the amplitude of the multimagnon states that build up the spin polaron wave function, leading to the reduction of the quasiparticle coherence. Based on Lanczos results, we discuss the validity of the spin polaron picture in the disordered phase.Comment: 9 pages, 12 figure

Pengaruh Penambahan Sumber Nitrogen Terhadap Hasil Fermentasi Nata De Coco

Nata de coco adalah makanan yang berasal dari hasil fermentasi air kelapa dengan bantuan bakteri Acetobacter xylinum. Nata ini dapat digunakan sebagai dessert dan kaya akan serat. Pembentukan nata sangat membutuhkan nutrisi nitrogen. Hal ini perlunya mengetahui jenis sumber nitrogen dan komposisi yang tepat dalam fermentasinya. Penelitian ini bertujuan mengetahui pengaruh perbedaan sumber nirogen (urea, ZA, amonium sulfat,dan yeast ekstrak) serta mencari komposisi agar diperoleh nata dengan sifat fisik terbaik. Penelitian dilakukan dalam dua tahap yaitu mencari sumber nitrogen dan dilanjutkan mencari komposisi yang tepat. Hasil penelitian menunjukkan bahwa urea memberikan hasil terbaik dalam menghasilkan nata de coco dengan yield sebanyak 87,36 %, tebal 8,6 mm dengan komposisi sebanyak 5 gr dalam 500 ml air kelapa. Penelitian ini dharapkan mampu memberikan informasi sumber ntrogen dan komposisi yang tepat agar memperoleh hasil terbaik nata de coco