19,360 research outputs found

    Constraints to school effectiveness: what prevents poor schools from delivering results?

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    The poor state of quality education in South Africa is confirmed by the weak performance of South African students on international tests, even when compared to countries with comparatively poorer education systems. This paper aims to shed light on this issue through the use of the PIRLS 2006 dataset and education production function techniques. A unique feature of this dataset is that schools were able to choose the language in which the test was conducted. This provided a proxy for former school department, a feature that has not been captured in international survey datasets. A clear distinction between the historically black and the historically white, coloured and Indian school systems is needed in order to identify the different data generating processes at work. The regression model results reveal that family and student characteristics are undoubtedly important for performance within both school samples. At the level of the school, quite divergent school factors and classroom processes were found to have significant impacts on student performance across the two school systems. It is concluded that a lack of enabling conditions such as effective leadership, flexibility and autonomy, and a capable teaching force may contribute to certain school and classroom processes not playing a significant role in determining performance in the less affluent black school system.South Africa, Education, Education production function, Educational Achievement, Educational Inequality

    Guide Field Dependence of 3D X-Line Spreading During Collisionless Magnetic Reconnection

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    Theoretical arguments and large-scale two-fluid simulations are used to study the spreading of reconnection X-lines localized in the direction of the current as a func- tion of the strength of the out-of-plane (guide) magnetic field. It is found that the mech- anism causing the spreading is different for weak and strong guide fields. In the weak guide field limit, spreading is due to the motion of the current carriers, as has been pre- viously established. However, spreading for strong guide fields is bi-directional and is due to the excitation of Alfv\'en waves along the guide field. In general, we suggest that the X-line spreads bi-directionally with a speed governed by the faster of the two mecha- nisms for each direction. A prediction on the strength of the guide field at which the spread- ing mechanism changes is formulated and verified with three-dimensional simulations. Solar, magnetospheric, and laboratory applications are discussed.Comment: 9 pages, 6 figures, Submitted to JG

    Hot Routes: Developing a New Technique for the Spatial Analysis of Crime

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    The use of hotspot mapping techniques such as KDE to represent the geographical spread of linear events can be problematic. Network-constrained data (for example transport-related crime) require a different approach to visualize concentration. We propose a methodology called Hot Routes, which measures the risk distribution of crime along a linear network by calculating the rate of crimes per section of road. This method has been designed for everyday crime analysts, and requires only a Geographical Information System (GIS), and suitable data to calculate. A demonstration is provided using crime data collected from London bus routes

    A study of the usefulness of Skylab EREP data for earth resources studies in Australia

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    There are no author-identified significant results in this report

    Relative annoyance and loudness judgements of various simulated sonic boom waveforms

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    Effects of various simulated sonic boom waveforms on human subjective respons

    Idler-resonant femtosecond optical parametric oscillator with high mid-infra-red beam quality

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    We report an idler-resonant femtosecond optical parametric oscillator (OPO) with average output power of 520 mW, repetition-rate of 80 MHz, pulse duration of 90 fs and nearly diffraction-limited beam quality at ~2.4 µm

    Annoyance resulting from intrusion of aircraft sounds upon various activities

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    An experiment was conducted in which subjects were engaged in TV viewing, telephone listening, or reverie (no activity) for a 1/2-hour session. During the session, they were exposed to a series of recorded aircraft sounds at the rate of one flight every 2 minutes. Within each session, four levels of flyover noise, separated by dB increments, were presented several times in a Latin Square balanced sequence. The peak level of the noisiest flyover in any session was fixed at 95, 90, 85, 75, or 70 dBA. At the end of the test session, subjects recorded their responses to the aircraft sounds, using a bipolar scale which covered the range from very pleasant to extremely annoying. Responses to aircraft noises were found to be significantly affected by the particular activity in which the subjects were engaged. Not all subjects found the aircraft sounds to be annoying

    Effects of three activities on annoyance responses to recorded flyovers

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    Human subjects participated in an experiment in which they were engaged in TV viewing, telephone listening, or reverie (no activity) for a 1/2-hour session. During the session, they were exposed to a series of recorded aircraft sounds at the rate of one flight every 2 minutes. At each session, four levels of flyover noise, separated by 5 db increments were presented several times in a Latin Square balanced sequence. The peak levels of the noisiest flyover in any session was fixed at 95, 90, 85, 75, or 70 db. At the end of the test session, subjects recorded their responses to the aircraft sounds, using a bipolar scale which covered the range from very pleasant to extremely annoying. Responses to aircraft noises are found to be significantly affected by the particular activity in which the subjects are engaged

    Sheraton Inn| A marketing study

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