Grade 7 teachers' and prospective teachers' content knowledge of geometry

The geometry content knowledge of Grade 7 teachers (n =18) and prospective teachers (n =100) was investigated, using the Van Hiele theory and acquisition scales of Gutiérrez, Jaime and Fortuny. Results indicated that both teacher and prospective teacher populations failed to reach the level of geometric thinking and degree of acquisition expected from successful teachers. The impact of teaching experience and different pre-service time frames (3 years vs 4 years) on the level of geometrical thought was also investigated. The conclusion was that teachers and prospective teachers do not have adequate control of the Grade 7 geometry subject-matter they have to teach. This holds implications both for pre-service and in-service teacher education as well as classroom practice. South African Journal of Education Vol.23(3) 2003: 199-20

Specific Localization of β-Arrestin2 in Myenteric Plexus of Mouse Gastrointestinal Tract

Abstract β-arrestin2 is a key molecule involved in signaling and internalization of activated G protein-coupled receptors including µ-opioid receptors (MOR). Previously we have shown that decreased expression of β-arrestin2 upon chronic morphine is associated with the development of opioid tolerance in the gastrointestinal tract. However, the localization of β-arrestin2 within the gastrointestinal wall is not known. In this study we found that β-arrestin2 is localized in the soma of a select group of neurons in the myenteric ganglia but not in smooth muscle. The density of β-arestin2 was significantly higher in the ileum than the colon. We identified four variants of β-arrestin2 in the ileum, with ARRB-005 and ARRB-013 being the most abundant. Further, the current study utilized multiple-labeling immunofluorescence to characterize the chemical coding of neurons expressing β-arrestin2 in the murine myenteric plexus and the co-localization of MOR1 and β-arrestin2. β-arrestin2 co-localized with choline acetyltransferase and calretinin. In contrast, β-arrestin2 neither co-localized with substance P, nitric oxide synthase nor calbindin. Genetic deletion of β-arrestin2 did not affect cholinergic neuron activation by nicotine in the isolated ileum (-log M EC50: wild type = 5.8 vs. β-arrestin2 knockout = 5.9). Our findings suggest specificity in the localization of β-arrestin2 in the myenteric plexus within MOR1-expressing neurons and provide a relation for direct intracellular crosstalk between MOR1 receptor activation and β-arrestin2 signaling in the myenteric neurons. β-arrestin2 deletion does not directly alter basal enteric cholinergic neuronal function

Neutron Halo Isomers in Stable Nuclei and their Possible Application for the Production of Low Energy, Pulsed, Polarized Neutron Beams of High Intensity and High Brilliance

We propose to search for neutron halo isomers populated via $\gamma$-capture in stable nuclei with mass numbers of about A=140-180 or A=40-60, where the $4s_{1/2}$ or $3s_{1/2}$ neutron shell model state reaches zero binding energy. These halo nuclei can be produced for the first time with new $\gamma$-beams of high intensity and small band width ($\le$ 0.1%) achievable via Compton back-scattering off brilliant electron beams thus offering a promising perspective to selectively populate these isomers with small separation energies of 1 eV to a few keV. Similar to single-neutron halo states for very light, extremely neutron-rich, radioactive nuclei \cite{hansen95,tanihata96,aumann00}, the low neutron separation energy and short-range nuclear force allows the neutron to tunnel far out into free space much beyond the nuclear core radius. This results in prolonged half lives of the isomers for the $\gamma$-decay back to the ground state in the 100 ps-$\mu$s range. Similar to the treatment of photodisintegration of the deuteron, the neutron release from the neutron halo isomer via a second, low-energy, intense photon beam has a known much larger cross section with a typical energy threshold behavior. In the second step, the neutrons can be released as a low-energy, pulsed, polarized neutron beam of high intensity and high brilliance, possibly being much superior to presently existing beams from reactors or spallation neutron sources.Comment: accepted for publication in Applied Physics

Technological pedagogical content knowledge in South African mathematics classrooms: A secondary analysis of SITES 2006 data

This article reports on a secondary data analysis conducted on the South African mathematics teachers’ dataset of the Second Information Technology in Education Study (SITES 2006). The sample consisted of a stratified sample of 640 mathematics teachers from 504 randomly selected computer-using and non–computer-using schools that completed the SITES 2006 teachers’ questionnaire, which investigated their pedagogical use of Information Communication Technology (ICT). The purpose of the current investigation was to investigate the level of Technological Pedagogical Content Knowledge (TPACK) of mathematics teachers, and how TPACK attributes contribute towards more effective Grade 8 mathematics teaching in South African schools, using the TPACK conceptual framework. The findings are presented according to the three clusters identified through the association between the main variables of the TPACK model and other variables on the SITES 2006 teachers’ questionnaire: (1) impact of ICT use, (2) teacher practices and (3) barriers. A Cramér V of between 0.3 and 0.4 was considered to signal a medium effect that tended towards practically significant association, and a Cramér V of 0.4 or larger was considered to signal a large effect with practically significant association. The results indicate that the TPACK of mathematics teachers contributes towards more effective Grade 8 mathematics teaching in South African schools

Quality education

This book investigates the intersections between education, social justice, gendered violence and human rights in South African schools and universities. The rich and multifarious tapestry of scholarship and literature emanating from South African classrooms provides a fascinating lens through which we can understand the complex consequences of the economies of education, social justice imperatives, gendered violence on the lives of women and children, and marginalised communities. The scholarship in the book challenges readers to imagine alternative futures predicated on the transformational capacity of a democratic South Africa. Contributors to this volume examine the many ways in which social justice and gendered violence mirrors, expresses, projects and articulates the larger phenomenon of human rights violations in Africa and how, in turn, the discourse of human rights informs the ways in which we articulate, interrogate, conceptualise, enact and interpret quality education. The book also wrestles with the linguistic contradictions and ambiguities in the articulation of quality education in public and private spaces. This book is essential reading for scholars seeking solid grounding in exploring quality education, the instances of epistemic disobedience, the political implications of place and power, and human rights in theory and practice

Quality education

This book investigates the intersections between education, social justice, gendered violence and human rights in South African schools and universities. The rich and multifarious tapestry of scholarship and literature emanating from South African classrooms provides a fascinating lens through which we can understand the complex consequences of the economies of education, social justice imperatives, gendered violence on the lives of women and children, and marginalised communities. The scholarship in the book challenges readers to imagine alternative futures predicated on the transformational capacity of a democratic South Africa. Contributors to this volume examine the many ways in which social justice and gendered violence mirrors, expresses, projects and articulates the larger phenomenon of human rights violations in Africa and how, in turn, the discourse of human rights informs the ways in which we articulate, interrogate, conceptualise, enact and interpret quality education. The book also wrestles with the linguistic contradictions and ambiguities in the articulation of quality education in public and private spaces. This book is essential reading for scholars seeking solid grounding in exploring quality education, the instances of epistemic disobedience, the political implications of place and power, and human rights in theory and practice

Extraction and Inhibition of Enzymatic Activity of Botulinum Neurotoxins/A1, /A2, and /A3 by a Panel of Monoclonal Anti-BoNT/A Antibodies

Botulinum neurotoxins (BoNTs) are extremely potent toxins that are capable of causing death or respiratory failure leading to long-term intensive care. Treatment includes serotype-specific antitoxins, which must be administered early in the course of the intoxication. Rapidly determining human exposure to BoNT is an important public health goal. In previous work, our laboratory focused on developing Endopep-MS, a mass spectrometry-based endopeptidase method for detecting and differentiating BoNT/A–G serotypes in buffer and BoNT/A, /B, /E, and /F in clinical samples. We have previously reported the effectiveness of antibody-capture to purify and concentrate BoNTs from complex matrices, such as clinical samples. Because some antibodies inhibit or neutralize the activity of BoNT, the choice of antibody with which to extract the toxin is critical. In this work, we evaluated a panel of 16 anti-BoNT/A monoclonal antibodies (mAbs) for their ability to inhibit the in vitro activity of BoNT/A1, /A2, and /A3 complex as well as the recombinant LC of A1. We also evaluated the same antibody panel for the ability to extract BoNT/A1, /A2, and /A3. Among the mAbs, there were significant differences in extraction efficiency, ability to extract BoNT/A subtypes, and inhibitory effect on BoNT catalytic activity. The mAbs binding the C-terminal portion of the BoNT/A heavy chain had optimal properties for use in the Endopep-MS assay

Perspectives in visual imaging for marine biology and ecology: from acquisition to understanding

Durden J, Schoening T, Althaus F, et al. Perspectives in Visual Imaging for Marine Biology and Ecology: From Acquisition to Understanding. In: Hughes RN, Hughes DJ, Smith IP, Dale AC, eds. Oceanography and Marine Biology: An Annual Review. 54. Boca Raton: CRC Press; 2016: 1-72