On Geodesic Motion in Horava-Lifshitz Gravity

We propose an action for a free particle in Horava-Lifshitz gravity based on Foliation Preserving Diffeomorphisms. The action reduces to the usual relativistic action in the low energy limit and allows for subluminal and superluminal motions with upper and lower bounds on velocity respectively. We find that deviation from general relativity is governed by a position dependent coupling constant which also depends on the mass of the particle. As a result, light-like geodesics are not affected whereas massive particles follow geodesics that become mass dependent and hence the equivalence principle is violated. We make an exact study for geodesics in flat space and a qualitative analysis for those in a spherically symmetric curved background.Comment: 12 pages, Dedicated to Farhad Ardalan on his 70th birthda

On Special Berwald Metrics

In this paper, we study a class of Finsler metrics which contains the class of Berwald metrics as a special case. We prove that every Finsler metric in this class is a generalized Douglas-Weyl metric. Then we study isotropic flag curvature Finsler metrics in this class. Finally we show that on this class of Finsler metrics, the notion of Landsberg and weakly Landsberg curvature are equivalent

The role of task-supported language teaching in EFL learner’s writing performance and grammar gains

Recent research in SLA advocates the use of task as a useful class activity claiming that task approximates language use in the context of classroom to the way language is used in the real world. Framed under a cognitive framework to task-based language teaching, this study was set out to investigate whether task-based oriented activities bear any superiority to that of more traditional ones evident in PPP (Presentation-Practice-Production) model. Twenty eight female pre-intermediate participants studying English in one language school in Urmia, Iran, took part in the study. They participated in ten half-an-hour long sessions of instruction during which they were instructed four structural points: simple past, simple present, present continuous, and ‘There is/There are/How much/How many’ structures. PPP group received their treatment through conventional approach and task-based group, through task-oriented activities. The quantitative analysis performed on the post-test (consisting of a grammar recognition test and a writing activity) suggested that participants in the PPP group did significantly better in the grammar recognition section of the post-test. However, their counterparts in the task group gained better scores in the writing section of the test. Further findings and implications are discussed in the paper