Cohomologies on almost complex manifolds and the ∂∂ˉ\partial \bar{\partial}-lemma

We study cohomologies on an almost complex manifold $(M, J)$, defined using the Nijenhuis-Lie derivations $\mathcal{L}_J$ and $\mathcal{L}_N$ induced from the almost complex structure $J$ and its Nijenhuis tensor $N$, regarded as vector-valued forms on $M$. We show how one of these, the $N$-cohomology $H^{\bullet}_N (M)$, can be used to distinguish non-isomorphic non-integrable almost complex structures on $M$. Another one, the $J$-cohomology $H^{\bullet}_J (M)$, is familiar in the integrable case but we extend its definition and applicability to the case of non-integrable almost complex structures. The $J$-cohomology encodes whether a complex manifold satisfies the $\partial \bar{\partial}$-lemma, and more generally in the non-integrable case the $J$-cohomology encodes whether $(M, J)$ satisfies the $\mathrm{d} \mathcal{L}_J$-lemma, which we introduce and motivate in this paper. We discuss several explicit examples in detail, including a non-integrable example. We also show that $H^k_J$ is finite-dimensional for compact integrable $(M, J)$, and use spectral sequences to establish partial results on the finite-dimensionality of $H^k_J$ in the compact non-integrable case.Comment: 23 pages. Version 3: one harmless sign error was corrected. Final version, to appear in "Asian Journal of Mathematics

Black Holes at the LHC: Progress since 2002

We review the recent noticeable progresses in black hole physics focusing on the up-coming super-collider, the LHC. We discuss the classical formation of black holes by particle collision, the greybody factors for higher dimensional rotating black holes, the deep implications of black hole physics to the `energy-distance' relation, the security issues of the LHC associated with black hole formation and the newly developed Monte-Carlo generators for black hole events.Comment: 6 pages, 10 figures, Plenary talk given at the 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY08), Seoul, Korea (June 16-21, 2008). To be published in the Conference Proceeding

Inflation in the nonminimal theory with `K(phi)R' term

A class of inflationary models with the nonminimal coupling term `K(phi)R' is considered. We show that the successful inflation can take place if the ratio between the square of the nonminimal coupling term and the potential for the scalar goes asymptotically constant.Comment: 3 pages, 1 figure, Talk given at 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY08), Seoul, Korea, 16-21 Jun 200

The effect of input frequency and linguistic complexity on the learning of bei2 constructions in Cantonese preschoolers

Thesis (B.Sc)--University of Hong Kong, 2005.Also available in print.A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2005.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

MODELING AND SIMULATION OF A LEAN SYSTEM. CASE STUDY OF A PAINT LINE IN A FURNITURE COMPANY

Since they were first developed, lean methodologies have grown in importance and scope and have been applied in both manufacturing and service. However, determining how to transform a common manufacturing company into a lean one, as well as how to evaluate the future company, are challenges for both researchers and manufacturers. This paper presents a case study of a lean manufacturing implementation for the paint line system in a furniture company. A systematic method for execution is shown. In addition, a simulation model is constructed to evaluate the new system in comparison with the MRP system. The new system promises much improvement in terms of a resource’s utility and the system’s productivity.Lean Techniques, Simulation Model, Paint Line, Furniture Company.

Differ in Socio-Cognitive Processes? Some Comparisons Between Paper and Video Triggered PBL

This paper investigates whether paper and video triggers stimulate different social and cognitive processes during PBL. The study focused on how medical students identified and described problems, and how they built shared cognitions that lead them to diagnose and solve problems. The results showed that students who used video triggers put more effort into communicating their understanding of the problem and relevant knowledge than students who used paper triggers. The findings contribute to discussions on how to evaluate the effectiveness of different PBL triggers in order to better integrate them into the curriculum

Dysphagia management of elderly in nursing home : skills and knowledge of frontline staff

Dysphagia is a common geriatric disorder among institutionalized elderly. Appropriate management on dysphagia is important to ensure the health and quality of life of elderly residents. This study investigated the knowledge and skills on dysphagia management of the frontline staff in Hong Kong nursing homes. A total of 243 staff, including health workers, care workers and care worker assistants, were recruited from 12 government-supported residential care homes. All participants completed the Questionnaire of Dysphagia Management to assess their knowledge. The feeding skills of 109 participants were assessed through observation while they were feeding the elderly. Results showed that the participants demonstrated inadequate knowledge on dysphagia management and inappropriate feeding behaviors. Areas of insufficient knowledge and the reason of staff’s unsatisfactory level of knowledge on dysphagia management were discussed. Developing an effective training protocol for frontline staff on dysphagia management was recommended in order to improve the standard of government-supported health care services for elderly.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

An analysis of the participation of an online educational discussion forum - the study of Hong Kong Cyber Campus Forum

Information technology is now widely used in the education sector, and online discussion forum has been regarded as a useful tool for education. A large number of online forums have been set up with an unexamined assumption that participants will learn through interacting with others in the forums. This paper reports a case study of the discussion forum of the Hong Kong Cyber Campus (www.hkcampus.net). It is the in one of the largest public educational discussion forums in Hong Kong set up jointly by local higher education institutions, to provide a venue for educators, teachers, students and parents to discuss about educational issues and the use of information technology for teaching and learning. The current study addresses the following issues: (1) What are the major objects of discussion in the forum? (2) How the structure of the forum may affect interactions between the different types of participants? (3) To what extent is online discussion conducive to conceptual learning of the participants? (4) What are the characteristics of the interactions of the participants in online forum? (5) How should the moderator act effectively to facilitate discussion? What kinds of moderator's messages will spark off more discussion? What kinds of messages tend to end the discussion? To address these research questions, we have conducted an analysis of the messages of the forum generated in its first twelve months from Feb.1999 to Feb.2000. Some of the findings are highlighted in this paper, namely: (1) The objects of discussion are mostly about everyday work and life of students and teachers; (2) The structure of the forum does affect the amount of interaction between different types of participants; (3) Online discussion affords gathering opinion, exchanging information and expressing feelings; (4) Online forum appears weak in resolving conflicting views. Participants seldom exhibit a change of their beliefs during the discussion. It also tends to polarize the discussion, lead the participants to extreme points of view. This is especially salient when the participants do not share a common experience of the issue. (5) The kind of moderator's messages that try to round up, make conclusion and provide authoritative information tend to terminate the discussion, while the expression of example/experience with open meaning tend to spark off more discussion.published_or_final_versio