Investigating physical science teachers' classroom use of language during teaching

A research report submitted to the Faculty of Science, University of Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the Master’s Degree in Science Education May 2016Studies have revealed that the teacher’s science classroom language plays a critical role in learners’ understanding of science concepts. The quality of the teacher’s science language impacts on the quality of learning. Learners encounter difficulties with the science classroom language irrespective of whether they are first or second language speakers of the language of instruction. The difficulty of the science language is mainly due to words having different meanings in science as compared to their everyday meanings, and also the foreignness of some science words (Oyoo, 2012). The language in science is therefore distinct from everyday language. In the South African context, the strategies to improve the quality of science education in secondary schools have not included the language. This study focus on the quality of the teachers’ science language in physical science classrooms. In this study data was collected by means of lesson observations of participant teachers followed by interview of one of the participant teacher. Two teachers participated in the study, and both teachers were from the same school. One teacher was teaching grade 10 physical science and the other teacher was teaching grade 11 physical science. Content analysis was used to analyse both lesson observation and interview transcripts. The findings from the lesson observation revealed that participant teachers overlooked explanation of some technical words as well as some non-technical words used in science context. The interview with one of the teachers showed an unawareness of the difficulty of the science language as he pointed that there was little difference between the science language and everyday language. The study recommends that there should be teacher development programmes dealing specifically with the language problem in science.M T 201

Frames in News Discourse on Nelson Mandela’s illness and Hospitalisation: A Study of Nigerian and Zimbabwean Newspapers

This study is a cross-national investigation in the use of frames in news coverage of an event which has international significance-the flashpoint of Nelson Mandela’s illness and hospitalization in South Africa. The study is anchored on the framing theory as espoused by Erving Goffman (1974). While studies examining frames in news coverage have gained significant ground in literature, there is paucity of studies examining news frames of events with health-cum-political undertones and how differences in national communication policies may influence frames in media discourse on such issues. To meet this gap, this present study analyses the news report of the illness and hospitalization of Nelson Mandela in leading newspapers in Nigeria and Zimbabwe. The study will also examine if major differences in frame choice emerged in the coverage between the countries. Qualitative content analysis methods will be employed in analyzing the coverage in the year 2013. The reliability of the inter-coded data will be tested using the Holsti’s index. The categories for measuring frames in the coverage are based on frames found in extant literatures. The expected contribution of this study would be an understanding of the congruence or disparity in the pattern of frames in the news coverage of similar events cross nationally. Understanding cross-national news discourse on the issue might be important for situating communication policy matters within health-cum-political contexts. Keywords: Frames, News, Discourse, Nelson Mandela, Illness and Hospitalization, Newspapers, Political, Policy, Cross-nationa

The challenge of integrated water resource management for improved rural livelihoods: Managing risk, mitigating drought and improving water productivity in the water scarce Limpopo Basin

The Challenge of Integrated Water Resource Management for Improved Rural Livelihoods: Managing Risk, Mitigating Drought and Improving Water Productivity in the Water Scarce Limpopo Basin: Integrated Water Resources Management (IWRM) is a systems approach to water management, based on the principle of managing the full water cycle. It is required, not only to balance water for food and nature, but also to unlock paths to sustainable development. A global hotspot area in terms of water for food and improved livelihoods is in the poverty stricken rural areas of water scarce semi-arid tropics, such as in the Limpopo basin. The improvement in resilience that the IWRM approach can impart to rural livelihood systems has been shown by a series of case studies in the Limpopo Basin

Bridging the gap between energy consumption and the indoor environmental quality of a 1960s-educational building

The fundamental purpose of a building has evolved from merely providing protection from external environmental climate to more emphasis on integrating building services through building regulations to provide the synergy of comfort, efficiency and safety to the indoor environment. This research recognizes the rising demand and increasing quality of indoor environmental quality (IEQ) in the modern society compared to the acceptable level of previous traditional buildings. Generally due to its varied operations, educational buildings, in this case University libraries have its own set of challenges and barriers such as minimizing damages and decay of books and maintaining indoor conditions with an oversight of providing good IEQ to occupants. This paper presents a detailed evaluation of a 1960s-educational library with 24-hour access at the University of Reading. Through in-situ measurements, modelling and simulations of the building’s energy consumption, IEQ parameters and occupancy patterns, investigations have been performed. Varied scenarios using the Integrated Environmental Solution (IES) software were also investigated. The findings illustrate that due to mixed façade configuration (i.e. sandstone and bricks) there is the unflinching need to balance aesthetics of the facade and functionality of a building to reduce excessive energy use via heating, without compromising on occupant comfort and well-being Although it is envisaged that refurbishing the library building will provide energy savings of up to 40%, this is farfetched and can only be achieved at the detriment of occupant comfort levels as evident in the simulation results, where these savings could not be realised. This paper further discusses the methods, scenarios, and results of ensuring good IEQ, comfort and energy efficiency are not been seen as mutually exclusive. This study forms part of ongoing research into the impact of educational buildings

Observation of strong Kondo like features and co-tunnelling in superparamagnetic GdCl3 filled 1D nanomagnets

Filling of carbon nanotubes has been tailored over years to modify the exceptional properties of the 1-dimensional conductor for magnetic property based applications. Hence, such a system exploits the spin and charge property of the electron, analogous to a quantum conductor coupled to magnetic impurities, which poses an interesting scenario for the study of Kondo physics and related phenomena. We report on the electronic transport properties of MWNTs filled with GdCl3 nanomagnets, which clearly show the co-existence of Kondo correlation and cotunelling within the superparamagnetic limit. The Fermi liquid description of the Kondo effect and the interpolation scheme are fitted to the resistance-temperature dependence yielding the onset of the Kondo scattering temperature and a Kondo temperature for this nanocomposite, respectively. Cotunneling of conduction electrons interfering with a Kondo type interaction has been verified from the exponential decay of the intensity of the fano shaped nonzero bias anomalous conductance peaks, which also show strong resonant features observed only in GdCl3 filled MWNT devices. Hence, these features are explained in terms of magnetic coherence and spin-flip effects along with the competition between the Kondo effect and co-tunneling. This study raises a new possibility of tailoring magnetic interactions for spintronic applications in carbon nanotube systems

Observation of a superparamagnetic breakdown in gadolinium chloride filled double-walled carbon nanotubes

In this article, the magnetic properties of gadolinium chloride-filled double-walled carbon nanotubes (GdCl3@DWNTs) in the temperature range 2-300 K are explored. The temperature-dependent phonon frequencies of the G-band were studied from 80-300 K to investigate the effect of temperature on the magnetic ordering. Temperature-dependent susceptibility measurements show that the GdCl3@DWNTs sample has a pronounced superparamagnetic phase from 83 K. The temperature dependence of the G-band frequency for filled tubes exhibited a distinct difference compared to pristine nanotubes, where a sharp phonon hardening at low temperatures was observed. A correlation between the onset temperature of superparamagnetism and the abrupt G-band phonon hardening in the filled tubes was verified. GdCl3@DWNTs were characterized by a finite remnant magnetization at 300 K which decreased as the temperature was lowered because of the presence of the discontinuous magnetic nanoparticles, providing a superparamagnetic contribution characterized by an S-shaped non-saturating hysteresis loop at 2 K. Remarkably, the onset of superparamagnetism, marked by the bifurcation point, occurred at roughly the same temperature where the G-band phonon frequency showed a pronounced hardening at approximately 80 K, indicating a close correlation between phonon modes and spin clusters

Kondo effect and enhanced magnetic properties in gadolinium functionalized carbon nanotube supramolecular complex

We report on the enhancement of magnetic properties of multiwalled carbon nanotubes (MWNTs) functionalized with a gadolinium based supramolecular complex. By employing a newly developed synthesis technique we find that the functionalization method of the nanocomposite enhances the strength of magnetic interaction leading to a large effective moment of 15.79 μB and nonsuperparamagnetic behaviour unlike what has been previously reported. Saturating resistance at low temperatures is fitted with the numerical renormalization group formula verifying the Kondo effect for magnetic impurities on a metallic electron system. Magnetoresistance shows devices fabricated from aligned gadolinium functionalized MWNTs (Gd-Fctn-MWNTs) exhibit spin-valve switching behaviour of up to 8%. This study highlights the possibility of enhancing magnetic interactions in carbon systems through chemical modification, moreover we demonstrate the rich physics that might be useful for developing spin based quantum computing elements based on one-dimensional (1D) channels

In vitro antioxidant activity of crude extracts of Harpagophytum zeyheri and their anti-inflammatory and cytotoxicity activity compared with diclofenac

BACKGROUND : This study evaluated the in vitro antioxidant activity and comparison of anti-inflammatory and cytotoxic activity of Harpagopytum zeyheri with diclofenac. METHODS : In vitro assays were conducted using water, ethanol, and ethyl acetate extracts of H.zeyheri. The antioxidant activity was evaluated using the 2,2′-diphenyl-1-picrylhydrazy (DPPH) and 2,2′- azino-bis (3- ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. The anti-inflammatory activity was determined by measuring the inhibition of nitric oxide (NO) on lipopolysaccharide (LPS)-induced RAW 264.7 mouse macrophages as well as cytokine (TNF-α and IL-10) expression on LPS-induced U937 human macrophages. For cytotoxicity, cell viability was determined using the 3-(4, 5-dimethylthiazol- 2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. RESULTS : The ethyl acetate extract had the lowest IC50 values in the DPPH (5.91 μg/ml) and ABTS (20.5 μg/ml) assay compared to other extracts. Furthermore, the ethyl acetate extracts effectively inhibited NO and TNF-α and proved to be comparable to diclofenac at some concentrations. All extracts of H. zeyheri displayed dose-dependent activity and were associated with low levels of human-IL-10 expression compared to quercetin. Furthermore, all extracts displayed low toxicity relative to diclofenac. CONCLUSIONS : These findings show that H. zeyheri has significant antioxidant activity. Additionally, similarities exist in the inflammatory activity of H. zeyheri to diclofenac at some concentrations as well as low toxicity in comparison to diclofenac.This manuscript is part of a PhD project supported by a grant (Grant: RB/58/ 16) from the Research Board of the National University of Science and Technology, Zimbabwe and Higherlife Foundation Delta Philanthropies Doctoral Fellowship (NCU56422B).https://bmccomplementmedtherapies.biomedcentral.com/am2022Paraclinical Science

Identification of groundnut (Arachis hypogaea) SSR markers suitable for multiple resistance traits QTL mapping in African germplasm

AbstractBackgroundThis study aimed to identify and select informative Simple Sequence Repeat (SSR) markers that may be linked to resistance to important groundnut diseases such as Early Leaf Spot, Groundnut Rosette Disease, rust and aflatoxin contamination. To this end, 799 markers were screened across 16 farmer preferred and other cultivated African groundnut varieties that are routinely used in groundnut improvement, some with known resistance traits.ResultsThe SSR markers amplified 817 loci and were graded on a scale of 1 to 4 according to successful amplification and ease of scoring of amplified alleles. Of these, 376 markers exhibited Polymorphic Information Content (PIC) values ranging from 0.06 to 0.86, with 1476 alleles detected at an average of 3.7 alleles per locus. The remaining 423 markers were either monomorphic or did not work well. The best performing polymorphic markers were subsequently used to construct a dissimilarity matrix that indicated the relatedness of the varieties in order to aid selection of appropriately diverse parents for groundnut improvement. The closest related varieties were MGV5 and ICGV-SM 90704 and most distant were Chalimbana and 47–10. The mean dissimilarity value was 0.51, ranging from 0.34 to 0.66.DiscussionOf the 376 informative markers identified in this study, 139 (37%) have previously been mapped to the Arachis genome and can now be employed in Quantitative Trait Loci (QTL) mapping and the additional 237 markers identified can be used to improve the efficiency of introgression of resistance to multiple important biotic constraints into farmer-preferred varieties of Sub-Saharan Africa

Tuning Magnetic Properties of a Carbon Nanotube-Lanthanide Hybrid Molecular Complex through Controlled Functionalization

Molecular magnets attached to carbon nanotubes (CNT) are being studied as potential candidates for developing spintronic and quantum technologies. However, the functionalization routes used to develop these hybrid systems can drastically affect their respective physiochemical properties. Due to the complexity of this systems, little work has been directed at establishing the correlation between the degree of functionalization and the magnetic character. Here, we demonstrate the chemical functionalization degree associated with molecular magnet loading can be utilized for controlled tuning the magnetic properties of a CNT-lanthanide hybrid complex. CNT functionalization degree was evaluated by interpreting minor Raman phonon modes in relation to the controlled reaction conditions. These findings were exploited in attaching a rare-earth-based molecular magnet (Gd-DTPA) to the CNTs. Inductively coupled plasma mass spectrometry, time-of-flight secondary ion mass spectrometry and super conducting quantum interference device (SQUID) measurements were used to elucidate the variation of magnetic character across the samples. This controlled Gd-DTPA loading on the CNT surface has led to a significant change in the nanotube intrinsic diamagnetism, showing antiferromagnetic coupling with increase in the Weiss temperature with respect to increased loading. This indicates that synthesis of a highly correlated spin system for developing novel spintronic technologies can be realized through a carbon-based hybrid material