Lack of lecturer clarity during instruction: Possible reason for poor throughput?

In South Africa, students’ academic success in tertiary environments  is generally low, despite governmental or institutional interventions. This article, underpinned by the General  Model of Instructional Communication by  McCroskey, Valencic and Richmond (2004), explores participant lecturers’ perceptions of lecturer clarity during instruction, and their students’. A mixed methods case study was conducted, with a convenience sample of seven lecturers, interviewed and observed in situ. Questionnaires were completed by 252 first year students at a South African university of technology.  Content and statistical analysis of the data revealed that a mismatch existed between lecturers’ perceptions of their own instructional clarity and their students’. The high percentage of students who felt lost during a lecture suggests a high level of instructional dissonance (Evans, 2005) which might account for a less-than desirable academic throughput. We recommend that institutions quality assure lecturers’ oral, written, content and process clarity prior to and during appointment.

Herbicide Control of Tall Larkspurs on Mountain Rangeland

Tall larkspurs kill more cattle on mountain rangelands than any other plant or disease. Tall larkspurs are principal components of tall forb communities and occur in patches associated with snow drifts in mountain big sagebrush, aspen and subalpine plant communities. Controlling larkspur patches can substantially reduce cattle deaths (3). Larkspur will never be eradicated, but if its density could be reduced to where a cow could not eat enough larkspur, fast enough, death losses can be reduced

Sensory augmentation with distal touch: The tactile helmet project

The Tactile Helmet is designed to augment a wearer's senses with a long range sense of touch. Tactile specialist animals such as rats and mice are capable of rapidly acquiring detailed information about their environment from their whiskers by using task-sensitive strategies. Providing similar information about the nearby environment, in tactile form, to a human operator could prove invaluable for search and rescue operations, or for partially-sighted people. Two key aspects of the Tactile Helmet are sensory augmentation, and active sensing. A haptic display is used to provide the user with ultrasonic range information. This can be interpreted in addition to, rather than instead of, visual or auditory information. Active sensing systems "are purposive and information-seeking sensory systems, involving task specific control of the sensory apparatus" [1]. The integration of an accelerometer allows the device to actively gate the delivery of sensory information to the user, depending on their movement. Here we describe the hardware, sensory transduction and characterisation of the Tactile Helmet device, before outlining potential use cases and benefits of the system. © 2013 Springer-Verlag Berlin Heidelberg

Whiskered texture classification with uncertain contact pose geometry

Tactile sensing can be an important source of information for robots, and texture discrimination in particular is useful in object recognition and terrain identification. Whisker based tactile sensing has recently been shown to be a promising approach for mobile robots, using simple sensors and many classification approaches. However these approaches have often been tested in limited environments, and have not been compared against one another in a controlled way. A wide range of whisker-object contact poses are possible on a mobile robot, and the effect such contact variability has on sensing has not been properly investigated. We present a novel, carefully controlled study of simple surface texture classifiers on a large set of varied pose conditions that mimic those encountered by mobile robots. Namely, single brief whisker contacts with textured surfaces at a range of surface orientations and contact speeds. Results show that different classifiers are appropriate for different settings, with spectral template and feature based approaches performing best in surface texture, and contact speed estimation, respectively. The results may be used to inform selection of classifiers in tasks such as tactile SLAM

CrunchBot : a mobile whiskered robot platform

CrunchBot is a robot platform for developing models of tactile perception and navigation. We present the architecture of CrunchBot, and show why tactile navigation is difficult. We give novel real-time performance results from components of a tactile navigation system and a description of how they may be integrated at a systems level. Components include floor surface classification, radial distance estimation and navigation. We show how tactile-only navigation differs fundamentally from navigation tasks using vision or laser sensors, in that the assumptions about the data preclude standard algorithms (such as extended Kalman Filters) and require brute-force methods

First order phase transition with a logarithmic singularity in a model with absorbing states

Recently, Lipowski [cond-mat/0002378] investigated a stochastic lattice model which exhibits a discontinuous transition from an active phase into infinitely many absorbing states. Since the transition is accompanied by an apparent power-law singularity, it was conjectured that the model may combine features of first- and second-order phase transitions. In the present work it is shown that this singularity emerges as an artifact of the definition of the model in terms of products. Instead of a power law, we find a logarithmic singularity at the transition. Moreover, we generalize the model in such a way that the second-order phase transition becomes accessible. As expected, this transition belongs to the universality class of directed percolation.Comment: revtex, 4 pages, 5 eps figure

The interpretive approach to religious education : challenging Thompson's interpretation

In a recent book chapter, Matthew Thompson makes some criticisms of my work, including the interpretive approach to religious education and the research and activity of Warwick Religions and Education Research Unit. Against the background of a discussion of religious education in the public sphere, my response challenges Thompson’s account, commenting on his own position in relation to dialogical approaches to religious education. The article rehearses my long held view that the ideal form of religious education in fully state funded schools of a liberal democracy should be ‘secular’ but not ‘secularist’; there should be no implication of an axiomatic secular humanist interpretation of religions

Boron Fullerenes: A First-Principles Study

A family of unusually stable boron cages was identified and examined using first-principles local density functional method. The structure of the fullerenes is similar to that of the B12 icosahedron and consists of six crossing double-rings. The energetically most stable fullerene is made up of 180 boron atoms. A connection between the fullerene family and its precursors, boron sheets, is made. We show that the most stable boron sheets are not necessarily precursors of very stable boron cages. Our finding is a step forward in the understanding of the structure of the recently produced boron nanotubes.Comment: 10 pages, 4 figures, 1 tabl

Equilibrium Properties of A Monomer-Monomer Catalytic Reaction on A One-Dimensional Chain

We study the equilibrium properties of a lattice-gas model of an $A + B \to 0$ catalytic reaction on a one-dimensional chain in contact with a reservoir for the particles. The particles of species $A$ and $B$ are in thermal contact with their vapor phases acting as reservoirs, i.e., they may adsorb onto empty lattice sites and may desorb from the lattice. If adsorbed $A$ and $B$ particles appear at neighboring lattice sites they instantaneously react and both desorb. For this model of a catalytic reaction in the adsorption-controlled limit, we derive analytically the expression of the pressure and present exact results for the mean densities of particles and for the compressibilities of the adsorbate as function of the chemical potentials of the two species.Comment: 19 pages, 5 figures, submitted to Phys. Rev.

Numerical Solutions of ideal two-fluid equations very closed to the event horizon of Schwarzschild black hole

The 3+1 formalism of Thorne, Price and Macdonald has been used to derive the linear two-fluid equations describing transverse and longitudinal waves propagating in the two-fluid ideal collisionless plasmas surrounding a Schwarzschild black hole. The plasma is assumed to be falling in radial direction toward the event horizon. The relativistic two-fluid equations have been reformulate, in analogy with the special relativistic formulation as explained in an earlier paper, to take account of relativistic effects due to the event horizon. Here a WKB approximation is used to derive the local dispersion relation for these waves and solved numerically for the wave number k.Comment: 16 pages, 15 figures. arXiv admin note: text overlap with arXiv:0902.3766, arXiv:0807.459