A study of possible temporal and latitudinal variations in the properties of the solar tachocline

Temporal variations of the structure and the rotation rate of the solar tachocline region are studied using helioseismic data from the Global Oscillation Network Group (GONG) and the Michelson Doppler Imager (MDI) obtained during the period 1995--2000. We do not find any significant temporal variation in the depth of the convection zone, the position of the tachocline or the extent of overshoot below the convection zone. No systematic variation in any other properties of the tachocline, like width, etc., is found either. Possibility of periodic variations in these properties is also investigated. Time-averaged results show that the tachocline is prolate with a variation by about 0.02R_sun in its position. The depth of the convection zone or the extent of overshoot does not show any significant variation with latitude.Comment: To appear in MNRA

On the magnetic field required for driving the observed angular-velocity variations in the solar convection zone

A putative temporally varying circulation-free magnetic-field configuration is inferred in an equatorial segment of the solar convection zone from the helioseismologically inferred angular-velocity variation, assuming that the predominant dynamics is angular acceleration produced by the azimuthal Maxwell stress exerted by a field whose surface values are consistent with photospheric line-of-sight measurements.Comment: to appear in MNRA

Letter, H. B. Gough to Dudley Brainard [August 8, 1947]

Letter, H. B. Gough to Dudley Brainardhttps://repository.stcloudstate.edu/brainard-letters/1104/thumbnail.jp

Review of meteoroid-bumper interaction studies at McGill University

Experimental investigation of meteoroid-bumper impact, debris cloud expansion, and second surface pressure loadin

Alternative perspectives on orality, literacy and education: a view from South Africa.

The question of the 'great divide' between orality and literacy has been critically addressed by various scholars of literacy, including social literacy theorists. This paper uses the notions of primary and secondary discourse across both oral and literate contexts to examine this 'divide'. Using evidence from the oral tradition of the Xhosa, it is shown that 'traditional' societies have well-established primary and secondary discourse types. Against this understanding, the issue of 'access' to Western academic literacy is examined. It is argued that within the changing context of South African society and as a direct result of former apartheid policies, individuals may have failed to acquire the cultural capital of both oral secondary and literate secondary discourse types. The literate secondary discourse practices of Xhosa-speaking students at univer¬sity are explored through an analysis of student writing. This paper then reports on several projects which attempt to address some of the concerns of academic staff with respect to student writing. In particular, this section argues for a broadening of the notion of 'academic literacy' and suggests some ways in which texts derived from the oral tradition may be used to develop awareness of secondary discourse types

Applying linguistics: Developing cognitive skills through multimedia

This paper examines the effectiveness of linguistic analysis in developing scientific thinking skills and scientific attitudes. It reports on a project established at a South Africa university in South Africa which engaged students in the analysis of code-mixed data. Students who participated in the project showed gains in being able to analyze linguistic data using problem solving skills. While transfer of such skills to mainstream science teaching was not investigated, the study confirms the effectiveness of linguistic analysis in engaging students in the activities associated with the development of skills for science

Modular Quantum Memories Using Passive Linear Optics and Coherent Feedback

In this paper, we show that quantum memory for qudit states encoded in a single photon pulsed optical field has a conceptually simple modular realization using only passive linear optics and coherent feedback. We exploit the idea that two decaying optical cavities can be coupled in a coherent feedback configuration to create an internal mode of the coupled system which is isolated and decoherence-free for the purpose of qubit storage. The qubit memory can then be switched between writing/read-out mode and storage mode simply by varying the routing of certain freely propagating optical fields in the network. It is then shown that the qubit memories can be interconnected with one another to form a qudit quantum memory. We explain each of the phase of writing, storage, and read-out for this modular quantum memory scheme. The results point a way towards modular architectures for complex compound quantum memories