A teacher-researcher’s exploration of learner engagement with corrective feedback : an action research

Corrective feedback includes oral corrective feedback and written corrective feedback. Although a number of studies have examined the impact of student engagement with written corrective feedback in second language (L2) acquisition studies, student engagement with oral corrective feedback has been under-conceptualised and under-explored. In addition, there are a substantial number of studies that have investigated the effect of student engagement with corrective feedback for higher education, but only a few studies focus on primary and high schools. This research explores the types of oral corrective feedback that foster young students’ engagement in Chinese in the L2 classroom in an Australia context, thereby helping beginning Chinese L2 teachers to improve their teaching ability. In this study, the teacher-researcher completed two cycles of data collection using an action research design to explore the phenomena. Quantitative and qualitative research methods were both used to investigate young students’ engagement with oral corrective feedback. Data was collected through questionnaires, semi-structured interviews, focus group interviews, classroom observation and self-reflective journals. It was found that different types of oral corrective feedback may affect student engagement to varying degrees in the Chinese classrooms as a number of factors influence the effectiveness of corrective feedback. In addition, language proficiency level affected student engagement when the teacher-researcher implemented the different types of oral corrective feedback. Comparatively more explicit feedback types led to better student engagement for the advanced level students, while more implicit feedback could better engage the students with lower language proficiency. Several implications and recommendations were made at the end of this thesis, highlighting the importance of oral corrective feedback for young learners in the Chinese as second language classes

Inhibition of Subsets of G Protein-coupled Receptors by Empty Mutants of G Protein α Subunits in Go, G11, and G16

We previously reported that the xanthine nucleotide binding Goα mutant, GoαX, inhibited the activation of Gi-coupled receptors. We constructed similar mutations in G11α and G16α and characterized their nucleotide binding and receptor interaction. First, we found that G11αX and G16αX expressed in COS-7 cells bound xanthine 5'-O-(thiotriphosphate) instead of guanosine 5'-O-(thiotriphosphate). Second, we found that G11αX and G16αX interacted with βγ subunits in the presence of xanthine diphosphate. These experiments demonstrated that G11aαX and G16αX were xanthine nucleotide-binding proteins, similar to GoαX. Third, in COS-7 cells, both G11αX and G16αX inhibited the activation of Gq-coupled receptors, whereas only G16αX inhibited the activation of Gi-coupled receptors. Therefore, when in the nucleotide-free state, empty G11αX and G16αX appeared to retain the same receptor binding specificity as their wild-type counterparts. Finally, we found that GoαX, G11αX, and G16αX all inhibited the endogenous thrombin receptors and lysophosphatidic acid receptors in NIH3T3 cells, whereas G11αX and G16αX, but not GoαX, inhibited the activation of transfected m1 muscarinic receptor in these cells. We conclude that these empty G protein mutants of Goα, G11α, and G16α can act as dominant negative inhibitors against specific subsets of G protein-coupled receptors

Low-frequency Landau–Zener–Stückelberg interference in dissipative superconducting qubits

Landau–Zener–Stückelberg (LZS) interference of continuously driven superconducting qubits is studied. Going beyond the second order perturbation expansion, we find a time dependent stationary population evolution as well as unsymmetrical microwave driven Landau–Zener transitions, resulting from the nonresonant terms which are neglected in rotating-wave approximation. For the low-frequency driving, the qubit population at equi-librium is a periodical function of time, owing to the contribution of the nonresonant terms. In order to obtain the average population, it is found that the average approximation based on the perturbation approach can be applied to the low-frequency region. For the extremely low frequency which is much smaller than the decoherence rate, we develop noncoherence approximation by dividing the evolution into discrete time steps during which the co-herence is lost totally. These approximations present comprehensive analytical descriptions of LZS interference in most of parameter space of frequency and decoherence rate, agreeing well with those of the numerical simula-tions and providing a simple but integrated understanding to system dynamics. The application of our models to microwave cooling can obtain the minimal frequency to realize effective microwave cooling

Age of Information: Design and Analysis of Optimal Scheduling Algorithms

Abstract: Age of information is a newly proposed metric that captures delay from an application layer perspective. The age measures the amount of time that elapsed from the moment the mostly recently received update was generated until the present time. In this paper, we study an age minimization problem over a wireless broadcast network with many users, where only one user can be served at a time. We formulate a Markov decision process (MDP) to find dynamic transmission scheduling schemes, with the purpose of minimizing the long-run average age. While showing that an optimal scheduling algorithm for the MDP is a simple stationary switch-type, we propose a sequence of finite-state approximations for our infinite-state MDP and prove its convergence. We then propose both optimal off-line and online scheduling algorithms for the finite-approximate MDPs, depending on knowledge of time-varying arrivals.National Science Foundation (U.S.) (award CNS-1701964

Electromagnetically induced interference in a superconducting flux qubit

Interaction between quantum two-level systems (qubits) and electromagnetic fields can provide additional coupling channels to qubit states. In particular, the interwell relaxation or Rabi oscillations, resulting, respective-ly, from the multi- or single-mode interaction, can produce effective crossovers, leading to electromagnetically induced interference in microwave driven qubits. The environment is modeled by a multimode thermal bath, ge-nerating the interwell relaxation. Relaxation induced interference, independent of the tunnel coupling, provides deeper understanding to the interaction between the qubits and their environment. It also supplies a useful tool to characterize the relaxation strength as well as the characteristic frequency of the bath. In addition, we demon-strate the relaxation can generate population inversion in a strongly driving two-level system. On the other hand, different from Rabi oscillations, Rabi-oscillation-induced interference involves more complicated and modulated photon exchange thus offers an alternative means to manipulate the qubit, with more controllable parameters in-cluding the strength and position of the tunnel coupling. It also provides a testing ground for exploring nonlinear quantum phenomena and quantum state manipulation in qubits either with or without crossover structure

Optimal cooling of a driven artificial atom in dissipative environment

We study microwave-driven cooling in a superconducting flux qubit subjected to environment noises. For the weak decoherence, our analytical results agree well with the experimental observations and show that the microwave amplitude for optimal cooling should depend linearly on the dc flux detuning. With the decoherence stronger, more vibrational degrees of freedom (analogous with atomic physics) couple in, making the ordinary cooling method less effective or even fail. We propose an improved cooling method, which can eliminate the perturbation of additional vibrational degrees of freedom hence keep high efficiency, even under the strong decoherence. Furthermore, we point out that the decoherence can tune the frequency where microwave-driven Landau–Zener transition reaches maximum, displaying the feature of incoherent dynamics which is important for the optimal cooling of qubits and other quantum systems