582 research outputs found

    Anti-discrimination measures in education: A comparative policy analysis

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    Efforts to tackle discrimination in access to basic services have shown mixed results in different country settings. This study examines the positive and negative outcomes attributed to anti-discrimination measures adopted in different country contexts and analyses the factors contributing to these outcomes, with a specific focus on anti-discrimination measures in education. An analysis of trends in inequalities in human development is used to identify three countries that have seen positive change in reducing inequalities and three countries that have seen negative change. This is followed by a literature review exploring the factors that have contributed to the changes observed in these six cases. We find that reductions in inequalities have been achieved in those countries where targeted measures have gone alongside universal measures, where the constitution is used to generate an equity-focused political discourse, and where evidence on exclusion from education has been taken up politically

    Lithostratigraphy of the Palaeoproterozoic Hekpoort formation (Pretoria Group, Transvaal Supergroup), South Africa

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    The Palaeoproterozoic Hekpoort Formation of the Pretoria Group is a lava-dominated unit that has a basin-wide extent throughout the Transvaal sub-basin of South Africa. Additional correlative units may be present in the Kanye sub-basin of Botswana. The key characteristic of the formation is its general geochemical uniformity. Volcaniclastic and other sedimentary rocks are relatively rare throughout the succession but may be dominant in some locations. Hekpoort Formation outcrops are sporadic throughout the basin and mostly occur in the form of gentle hills and valleys, mainly encircling Archaean domes and the Palaeoproterozoic Bushveld Complex (BC). The unit is exposed in the western Pretoria Group basin, sitting unconformably either on the Timeball Hill Formation or Boshoek Formation, which is lenticular there, and on top of the Boshoek Formation in the east of the basin. The unit is unconformably overlain by the Dwaalheuwel Formation. The type-locality for the Hekpoort Formation is the Hekpoort farm (504 IQ Hekpoort), ca. 60 km to the west-southwest of Pretoria. However, no stratotype has ever been proposed. A lectostratotype, i.e., the Mooikloof area in Pretoria East, that can be enhanced by two reference stratotypes are proposed herein. The Hekpoort Formation was deposited in a cratonic subaerial setting, forming a large igneous province (LIP) in which short-termed localised ponds and small braided river systems existed. It therefore forms one of the major Palaeoproterozoic magmatic events on the Kaapvaal Craton.http://sajg.geoscienceworld.orgam2021Geolog

    Seismic detection of rockslides at regional scale: examples from the Eastern Alps and feasibility of kurtosis-based event location

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    Seismic records can provide detailed insight into the mechanisms of gravitational mass movements. Catastrophic events that generate long-period seismic radiation have been studied in detail, and monitoring systems have been developed for applications on a very local scale. Here we demonstrate that similar techniques can also be applied to regional seismic networks, which show great potential for real-time and large-scale monitoring and analysis of rockslide activity. This paper studies 19 moderate-sized to large rockslides in the Eastern Alps that were recorded by regional seismic networks within distances of a few tens of kilometers to more than 200&thinsp;km. We develop a simple and fully automatic processing chain that detects, locates, and classifies rockslides based on vertical-component seismic records. We show that a kurtosis-based onset picker is suitable to detect the very emergent onsets of rockslide signals and to locate the rockslides within a few kilometers from the true origin using a grid search and a 1-D seismic velocity model. Automatic discrimination between rockslides and local earthquakes is possible by a combination of characteristic parameters extracted from the seismic records, such as kurtosis or maximum-to-mean amplitude ratios. We attempt to relate the amplitude of the seismic records to the documented rockslide volume and reveal a potential power law in agreement with earlier studies. Since our approach is based on simplified methods we suggest and discuss how each step of the automatic processing could be expanded and improved to achieve more detailed results in the future.</p

    Structural and Dynamic Numerical Models of Rockslides in the Carpathians and the Alps

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    peer reviewedThe stability of rock slopes is often guided by the structural geology of the rocks composing the slope. In this work, we analyse the influence of structural characteristics, and of their seismic response, on large and deep-seated rock slope failure development. The study is focused on the Tamins and Fernpass rockslides in the Alps and on the Balta and Eagles Lake rockslides in the southeastern Carpathians. These case studies are compared with catastrophic rock slope failures with ascertained or very likely seismic origin in the Tien Shan Mountains. The main goal is to identify features allowing to identify seismically induced deformation modes based on the source zone rock structures. We will present examples of classical anti-dip slope and along-strike rock structures that hint at a possible/partial seismic origin, but we will also consider a series of mixed structural types, which are more difficult to be interpreted. This morpho-structural study is supported by distinct element numerical modelling results showing that seismic shaking typically induces deeper seated deformation in initially ‘stable’ rock slopes. In addition, for failures partially triggered by dynamic shaking, these studies can help identify the contribution of the seismic factor to slope movements. The identification of the partial seismic origin on the basis of the dynamic response of rock structures can be particularly interesting for case histories in less seismically active mountain regions (in comparison with the Andes, Tien Shan, Pamirs), such as in the Alps and the Carpathian Mountains
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