Fostering self-regulated learning of Grade 10 learners by means of participatory action research

Self-regulated learning (SRL) skills are crucial to improving learner achievement, to supporting effective lifelong learning, and to developing the capability to overcome learning difficulties arising from a disadvantaged environment. However, only a few South African studies address the development of SRL skills of secondary school learners. By means of participatory action research (PAR), this study aimed to foster SRL of Grade 10 learners in a selected secondary school in an  underprivileged urban environment. An intervention programme consisting of 10 action research cycles was implemented with 35 learners over the course of 10 weeks. The study implemented quantitative and qualitative data collection methods using a study skills inventory, learner diaries, weekly class discussions and interviews. A statistically significant improvement in learners’ SRL skills, time management, attitudes, motivation and certain cognitive strategies was observed and reported by learners. However, a key finding was that additional support was  needed to improve learners’ meta-cognitive skills.Keywords: meta-cognition; participatory action research; secondary school learners; self-regulated learning; study strategie

Empirical measures of symmetry of market sentiments

The analysis of asset return series of equity prices and stock indices is a well-researched problem tackled by economists, business and financial analysts in the last few decades. It has captured the fancy of financial economists, global and local portfolio investment consultants, foreign investment institutions and the trading man in the street. In this paper a strong case is made to follow a new approach for any investor to foray into an unknown stock market. This approach is the market sentiment approach. We introduce the concept of market sentiments, their definitions and different constructs one may propose vis-a-vis asset return series. We formulate several concepts of symmetry of market sentiments and propose empirical measures to validate such types of symmetric market sentiments. The efficacies of these measures are evaluated using extensive simulation studies and the efficient measures are identified. As an application, we explore the nature of absolute market sentiments that prevailed in weekly mean asset returns of two domestic companies registered in Botswana Stock Exchange during the trading period: 4 January 2016 to 30 December 2016. Our analysis indicates that both companies are characterised by the presence of complete symmetric absolute market sentiments

Uneven surface moisture as a driver of dune formation on ephemeral lake beds under conditions similar to the present day: A model-based assessment from the Makgadikgadi Basin, northern Botswana

An association between salt pans or dry lake beds and distinctive crescentic lake-floor sand mounds (1–10 m high, tens to hundreds of metres wide) is commonplace in desert systems. In the Makgadikgadi Basin of northern Botswana, a debate about the formative processes of these landforms has persisted despite numerous morphometric, sedimentary and geochronological analyses, with mound landforms variously inferred to be aeolian dunes, subaqueous dunes, spring mounds or shoreline remnants. We propose a new formative mechanism which draws on the interaction between uneven moisture distribution on the pan surface and mobile aeolian sediments. We use a numerical model (ViSTA), which couples vegetation and aeolian sand transport dynamics, together with optically stimulated luminescence (OSL) dating of a mound in the Makgadikgadi Basin to investigate the feasibility of this ‘sticky mound hypothesis’. We find that under a range of modelled environmental conditions, uneven moisture distribution on the pan surface can lead to the development and stabilization of crescentic aeolian dunes, with these dunes growing upwind from the point of initial deposition, corresponding with the chronological data gained from OSL dating of a mound feature. On removal of this moisture, the modelled dunes erode and dissipate. These findings suggest that the formative mechanism of the mounds could be dependent on the interaction between differential drying of the pan surface and the competence of the aeolian sediment transport system across the pan floor

Phenotypic profile of Mycobacterium tuberculosis-specific CD4 T-cell responses in people with advanced human immunodeficiency virus who develop tuberculosis-associated immune reconstitution inflammatory syndrome

BACKGROUND: Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a frequent complication of cotreatment for TB and human immunodeficiency virus (HIV)-1. We characterized Mycobacterium tuberculosis (Mtb)-specific CD4 T-cell phenotype and transcription factor profile associated with the development of TB-IRIS. METHODS: We examined the role of CD4 T-cell transcription factors in a murine model of mycobacterial IRIS. In humans, we used a longitudinal study design to compare the magnitude of antiretroviral therapy, activation, transcription factor profile, and cytotoxic potential of Mtb-specific CD4 T cells between TB-IRIS (n = 25) and appropriate non-IRIS control patients (n = 18) using flow cytometry. RESULTS: In the murine model, CD4 T-cell expression of Eomesodermin (Eomes), but not Tbet, was associated with experimentally induced IRIS. In patients, TB-IRIS onset was associated with the expansion of Mtb-specific IFNγ+CD4 T cells (P = .039). Patients with TB-IRIS had higher HLA-DR expression (P = .016), but no differences in the expression of T-bet or Eomes were observed. At TB-IRIS onset, Eomes+Tbet+Mtb-specific IFNγ+CD4+ T cells showed higher expression of granzyme B in patients with TB-IRIS (P = .026). CONCLUSIONS: Although the murine model of Mycobacterium avium complex-IRIS suggests that Eomes+CD4 T cells underly IRIS, TB-IRIS was not associated with Eomes expression in patients. Mycobacterium tuberculosis-specific IFNγ+CD4 T-cell responses in TB-IRIS patients are differentiated, highly activated, and potentially cytotoxic

Phasenverhalten von Polyethylen in Mischsystemen

The phase behavior of PE in mixed systems is studied in this thesis. Theoretical aspects: thermodynamics of polymer solutions, IPNs, polymerization-induced phase separation. PE in non-reactive systems: solvents, alkanes, mixed solvents. PE in reactive systems: polymerization with BPO, polymerization with DCPO, glass transition temperature, crystallinity.SIGLEAvailable from: <a href=http://ArchiMeD.uni-mainz.de/pub/2003/0051/diss.pdf target=NewWindow>http://ArchiMeD.uni-mainz.de/pub/2003/0051/diss.pdf</a> / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman