1,987 research outputs found

    School Library Development Initiatives in a Democratic South Africa: Roles of the Various Stakeholders

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    Equitable resource allocation and provision is critical in all schools including those in the disadvantaged rural communities to improve learner outcomes and the quality of education irrespective of the educational paradigm. With a wide variety of educational resources in a school environment, quality of education and learner achievement can be entrenched and improved. However, the majority of the schools in poor and developing countries are still characterised by an inferior quality education and poor learner outcomes owing to an array of contextual realities and factors – amongst them high poverty levels and lack of adequate educational facilities and resources in schools. The aim of this conceptual article is to highlight the roles various stakeholders can play to advance and champion effective development of libraries in all South African schools in the post-apartheid era. Based on the literature review, the study highlights roles various stakeholders can play to champion and advance effective library development initiatives in all schools. The study recommends that a cohort of distinct stakeholders need to play their roles actively for all schools to have an effective library and information services (LIS) to enable teachers and learners to have equitable access to information for curriculum and non-curriculum related activities

    Transcending existing frontiers to achieve selected sustainable development goals: The role of community libraries in South Africa

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    Globally, extreme poverty remains an enormous socioeconomic and multifaceted challenge, which has a ripple effect on other factors that affect the quality of life of citizens. Continuing and expanding on the Millennium Development Goals (MDGs), the United Nations (UN) developed the Sustainable Development Goals (SDGs aimed at improving the livelihood of citizens by entrenching human development particularly in poor and developing countries. This is a conceptual paper based on the document analysis or literature review. The article is aimed at analysing information sources and highlights new frontiers community libraries can play in assisting the general South African public to be aware of the good intentions of the SDGs and to mobilise them to strategically work towards achieving them. As hubs for knowledge economy, community libraries need to transcend their existing frontiers to entrench socioeconomic development and transformation in South Africa to improve quality of life of the citizens

    Extended supersymmetric sigma models in AdS_4 from projective superspace

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    There exist two superspace approaches to describe N=2 supersymmetric nonlinear sigma models in four-dimensional anti-de Sitter (AdS_4) space: (i) in terms of N=1 AdS chiral superfields, as developed in arXiv:1105.3111 and arXiv:1108.5290; and (ii) in terms of N=2 polar supermultiplets using the AdS projective-superspace techniques developed in arXiv:0807.3368. The virtue of the approach (i) is that it makes manifest the geometric properties of the N=2 supersymmetric sigma-models in AdS_4. The target space must be a non-compact hyperkahler manifold endowed with a Killing vector field which generates an SO(2) group of rotations on the two-sphere of complex structures. The power of the approach (ii) is that it allows us, in principle, to generate hyperkahler metrics as well as to address the problem of deformations of such metrics. Here we show how to relate the formulation (ii) to (i) by integrating out an infinite number of N=1 AdS auxiliary superfields and performing a superfield duality transformation. We also develop a novel description of the most general N=2 supersymmetric nonlinear sigma-model in AdS_4 in terms of chiral superfields on three-dimensional N=2 flat superspace without central charge. This superspace naturally originates from a conformally flat realization for the four-dimensional N=2 AdS superspace that makes use of Poincare coordinates for AdS_4. This novel formulation allows us to uncover several interesting geometric results.Comment: 88 pages; v3: typos corrected, version published in JHE

    Steps in the bacterial flagellar motor

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    The bacterial flagellar motor is a highly efficient rotary machine used by many bacteria to propel themselves. It has recently been shown that at low speeds its rotation proceeds in steps [Sowa et al. (2005) Nature 437, 916--919]. Here we propose a simple physical model that accounts for this stepping behavior as a random walk in a tilted corrugated potential that combines torque and contact forces. We argue that the absolute angular position of the rotor is crucial for understanding step properties, and show this hypothesis to be consistent with the available data, in particular the observation that backward steps are smaller on average than forward steps. Our model also predicts a sublinear torque-speed relationship at low torque, and a peak in rotor diffusion as a function of torque

    Primed Infusion with Delayed Equilibrium of Gd.DTPA for Enhanced Imaging of Small Pulmonary Metastases.

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    To use primed infusions of the magnetic resonance imaging (MRI) contrast agent Gd.DTPA (Magnevist), to achieve an equilibrium between blood and tissue (eqMRI). This may increase tumor Gd concentrations as a novel cancer imaging methodology for the enhancement of small tumor nodules within the low signal-to-noise background of the lung

    Glucose lowering effect of transgenic human insulin-like growth factor-I from rice: in vitro and in vivo studies

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    <p>Abstract</p> <p>Background</p> <p>Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains.</p> <p>Results</p> <p>The plant-codon-optimized hIGF-I was introduced into rice via <it>Agrobacterium</it>-mediated transformation. To enhance the stability and yield of rhIGF-I, the endoplasmic reticulum-retention signal and glutelin signal peptide were used to deliver rhIGF-I to endoplasmic reticulum for stable accumulation. We found that only glutelin signal peptide could lead to successful expression of hIGF-I and one gram of hIGF-I rice grain possessed the maximum activity level equivalent to 3.2 micro molar of commercial rhIGF-I. <it>In vitro </it>functional analysis showed that the rice-derived rhIGF-I was effective in inducing membrane ruffling and glucose uptake on rat skeletal muscle cells. Oral meal test with rice-containing rhIGF-I acutely reduced blood glucose levels in streptozotocin-induced and Zucker diabetic rats, whereas it had no effect in normal rats.</p> <p>Conclusion</p> <p>Our findings provided an alternative expression system to produce large quantities of biologically active rhIGF-I. The provision of large quantity of recombinant proteins will promote further research on the therapeutic potential of rhIGF-I.</p

    Beyond rhetoric in debates about the ethics of marketing prescription medicines to consumers: The importance of vulnerability in people, situations and relationships

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    Background This article examines community responses to the marketing of prescription medicines. Historically, debates about such marketing have focused on alleged unscrupulousness of pharmaceutical companies and on the quality of information provided. 2 Methods Six focus groups were conducted in Sydney, Australia, three with older and three with younger community members. Analysis examined interactions between group members, the positions participants took up, conflicting arguments, and explanations for variation. Results Participants argued specifically rather than generally about consumer marketing of medicines. Neither the moral purpose of corporations nor the quality of information in advertisements was particularly important. Instead, pharmaceutical marketing was assessed in relation to vulnerabilities that existed in individual consumers, in doctors, in the contexts of illness and as a result of medications being potentially dangerous. Conclusions The critical ethical issue in prescription medicine marketing may be the existence of vulnerabilities and the responsibilities they may generate. We outline three possible policy responses suggested by these participants. Key words: DTCA, direct-to-consumer advertising, marketing, vulnerability, doctor-patient relationship, drug industryAustralian National Health and Medical Research Council (NHMRC) Grant 457497

    Water Challenges for Geologic Carbon Capture and Sequestration

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    Carbon capture and sequestration (CCS) has been proposed as a means to dramatically reduce greenhouse gas emissions with the continued use of fossil fuels. For geologic sequestration, the carbon dioxide is captured from large point sources (e.g., power plants or other industrial sources), transported to the injection site and injected into deep geological formations for storage. This will produce new water challenges, such as the amount of water used in energy resource development and utilization and the “capture penalty” for water use. At depth, brine displacement within formations, storage reservoir pressure increases resulting from injection, and leakage are potential concerns. Potential impacts range from increasing water demand for capture to contamination of groundwater through leakage or brine displacement. Understanding these potential impacts and the conditions under which they arise informs the design and implementation of appropriate monitoring and controls, important both for assurance of environmental safety and for accounting purposes. Potential benefits also exist, such as co-production and treatment of water to both offset reservoir pressure increase and to provide local water for beneficial use

    Goldstino superfields for spontaneously broken N=2 supersymmetry

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    We examine spontaneously broken N=2 supersymmetry in four dimensions and associate a spinor superfield with each Goldstino via a finite supersymmetry transformation with parameters that are the Grassmann coordinates of N=2 superspace. Making use of a special choice of coset parametrization allows us to develop a version of nonlinearly realized N=2 supersymmetry for which the associated Goldstino superfields are defined on harmonic superspace, thereby providing a natural mechanism for construction of a Goldstino action. The corresponding superfield Lagrangian is an O(4) multiplet. This property is used to reformulate the Goldstino action in projective superspace and in conventional N=2 superspace. We show how to generate matter couplings of the Goldstinos to supersymmetric matter using the N=2 harmonic, projective and full superspaces. As a bi-product of our consideration, we also derive an N=2 chiral Goldstino action.Comment: 20 pages, typos corrected, comments adde

    Geometric phase outside a Schwarzschild black hole and the Hawking effect

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    We study the Hawking effect in terms of the geometric phase acquired by a two-level atom as a result of coupling to vacuum fluctuations outside a Schwarzschild black hole in a gedanken experiment. We treat the atom in interaction with a bath of fluctuating quantized massless scalar fields as an open quantum system, whose dynamics is governed by a master equation obtained by tracing over the field degrees of freedom. The nonunitary effects of this system are examined by analyzing the geometric phase for the Boulware, Unruh and Hartle-Hawking vacua respectively. We find, for all the three cases, that the geometric phase of the atom turns out to be affected by the space-time curvature which backscatters the vacuum field modes. In both the Unruh and Hartle-Hawking vacua, the geometric phase exhibits similar behaviors as if there were thermal radiation at the Hawking temperature from the black hole. So, a measurement of the change of the geometric phase as opposed to that in a flat space-time can in principle reveal the existence of the Hawking radiation.Comment: 14 pages, no figures, a typo in the References corrected, version to appear in JHEP. arXiv admin note: text overlap with arXiv:1109.033
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