In-service mathematics teachers’ noticing of exemplary lessons: an exploratory study in China

Seed Fund of The Education University of Hong Kong, R4248: RG43/21-22R

Ethylene Response of Plum ACC Synthase 1 (ACS1) Promoter is Mediated through the Binding Site of Abscisic Acid Insensitive 5 (ABI5).

The enzyme 1-amino-cyclopropane-1-carboxylic acid synthase (ACS) participates in the ethylene biosynthesis pathways and it is tightly regulated transcriptionally and post-translationally. Notwithstanding its major role in climacteric fruit ripening, the transcriptional regulation of ACS during ripening is not fully understood. We studied fruit ripening in two Japanese plum cultivars, the climacteric Santa Rosa (SR) and its non-climacteric bud sport mutant, Sweet Miriam (SM). As the two cultivars show considerable difference in ACS expression, they provide a good system for the study of the transcriptional regulation of the gene. To investigate the differential transcriptional regulation of ACS1 genes in the SR and SM, their promoter region, which showed only minor sequence differences, was isolated and used to identify the binding of transcription factors interacting with specific ACS1 cis-acting elements. Three transcription factors (TFs), abscisic acid-insensitive 5 (ABI5), GLABRA 2 (GL2), and TCP2, showed specific binding to the ACS1 promoter. Synthetic DNA fragments containing multiple cis-acting elements of these TFs fused to β-glucuronidase (GUS), showed the ABI5 binding site mediated ethylene and abscisic acid (ABA) responses of the promoter. While TCP2 and GL2 showed constant and similar expression levels in SM and SR fruit during ripening, ABI5 expression in SM fruits was lower than in SR fruits during advanced fruit ripening states. Overall, the work demonstrates the complex transcriptional regulation of ACS1

Synchronization of time-delay systems with impulsive delay via an average impulsive estimation approach

We investigated synchronization of dynamic systems with mixed delays and delayed impulses. Using impulsive control method and the average impulsive interval approach, several Lyapunov sufficient conditions were given for ensuring synchronization in terms of impulsive perturbation and impulsive control, respectively. The derived conditions indicated that delays in continuous dynamical systems were flexible under impulsive perturbation and were not strictly dependent on the size of impulsive delays, and they may have a potential impact on synchronization of the considered system. In addition, applying the proposed concepts of average positive impulsive estimation and average impulsive estimation, we integrated the information in impulsive delay into the rate coefficient to eliminate the limitation of having the same threshold at each impulse point, while the impulsive delay maintained the synchronization effect. This was an improvement on the previous results obtained. Finally, we provided two numerical examples to illustrate the validity of our results

Automated road network extraction from high resolution multi-spectral imagery

ABSTRACT In this paper, a new approach to road network extraction from multi-spectral (MS) imagery is presented. The proposed approach begins with an image segmentation using a spectral clustering algorithm. This step focuses on the exploitation of the spectral information for feature extraction. The road cluster(s) is automatically identified using a fuzzy classifier based on a set of predefined membership functions for road surfaces and the corresponding normalized digital numbers in each multi-spectral band. A number of shape descriptors from the refined Angular Texture Signature are defined and used to reduce the misclassifications between roads and other spectrally similar objects such as parking lots, buildings or crop fields. An iterative and localized Radon transform is then performed on the classified and refined road pixels to extract road centerline segments. The detected road segments are further grouped to form the final road network, which is evaluated against a reference dataset. Our experiments on Ikonos MS, Quickbird MS, and color aerial imagery show that the proposed approach is effective in automating road network extraction from high resolution multi-spectral imagery. Results from two different evaluation schemes also indicated that the proposed approach has achieves a performance comparable to other methods

Fresh Perspectives on Motivation, Engagement, and Identity : An Introduction

The 13th International Congress on Mathematical Education [ICME-13] was organized in Hamburg, Germany in 2016. This chapter is the introduction to the book composed of the selected papers presented in the Topic Study Group 28 on “Affect, beliefs and identity in mathematics education”. After the conference, 33 reworked papers had been submitted for evaluation and, based on a peer-reviewing process, 15 chapters were judged to be suitable for inclusion in the book. These contributions were clustered as follows: a stand-alone overview chapter, followed by three sections under the headings of interest, motivation, and values; engagement and flow; and identity. To enrich and broaden the contents of the book even further, the book editors invited three established mathematics educators to each write a commentary and critique on one of the three clusters. Mathematics-related affect is a research area with a variety of theoretical approaches. The different sections of the book provide a rich and diverse spectrum of different approaches, exhibiting both chapters that build on extensive research in the field as well as interesting new openings to the directions less explored in mathematics education to this date. The commentary chapters and the final conclusion offer insightful reflections on this field of research.Peer reviewe

Multiple Bifurcations and Chaos in a Discrete Prey-Predator System with Generalized Holling III Functional Response

A prey-predator system with the strong Allee effect and generalized Holling type III functional response is presented and discretized. It is shown that the combined influences of Allee effect and step size have an important effect on the dynamics of the system. The existences of Flip and Neimark-Sacker bifurcations and strange attractors and chaotic bands are investigated by using the center manifold theorem and bifurcation theory and some numerical methods