7,643 research outputs found

    Unified Geometrically Nonlinear Formulation of All Higher-order Shear Deformation Theories for Cross-ply Plates

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    Several higher-order shear deformation theories have been proposed for laminated plates, based on the expansions of displacements across the thickness, which are the same for all layers. In this study, a unified formulation of all higher-order theories is presented for cross-ply laminated plates based on polynomial expansions of displacements in the thickness coordinate z. It includes all the models available in literature. The governing equations for linear static and free vibfation response, and for buckling under inplane load are derived. The expressions for the stiffness matrix, inertia matrix, geometric stiffness matrix, and the load vector are developed for a simply supported rectangular plate using Navier's solution. A general purpose, single programme has been developed for all higher-order laminated plate theories

    Empowered Empathetic Encounters: Building International Collaborations through researching writing in the context of South African Higher Education and Beyond

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    Abstract: In this article, the authors propose the idea of ‘empowered empathetic encounters’ as a key success factor in the building of effective international inter-institutional collaboration. By empowered empathetic encounters the authors mean those supported pivotal occasions where researchers meet with colleagues with whom they wish to collaborate in face-to-face settings in order to try to understand, in a meaningful way, each other’s concerns and what it means to live and work in each other’s contexts. In their work, the authors combine their personal and collective experiences with an analysis of these in the context of the existing literature. In this way, they wish to engage in a process of ‘thinking the cultural through the self’ (Probyn 1993) and ‘thinking theory WKURXJK’ researchers’ own experiences (Mann 2008, 10 – emphasis in original). They further suggest that engaged encounters of this nature can provide the bedrock for successful, longterm collaboration

    Undecidable properties of self-affine sets and multi-tape automata

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    We study the decidability of the topological properties of some objects coming from fractal geometry. We prove that having empty interior is undecidable for the sets defined by two-dimensional graph-directed iterated function systems. These results are obtained by studying a particular class of self-affine sets associated with multi-tape automata. We first establish the undecidability of some language-theoretical properties of such automata, which then translate into undecidability results about their associated self-affine sets.Comment: 10 pages, v2 includes some corrections to match the published versio

    Vulnerability from storm surges and cyclone wind fields on the coast of Andhra Pradesh, India

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    The results presented here are from a study conducted for the government of the state of Andhra Pradesh (GOAP) in India, as part of a World Bank project on cyclone mitigation. A set of detailed maps were prepared depicting the Physical Vulnerability (PV), specifically storm surge inundation zones are shown for frequent occurrence, 50-year return period, likely scenario for global warming and extreme global warming. Similarly vulnerable areas from strong wind field from tropical cyclones (TCS) are also presented for the same four parameters. Vulnerability zones are presented from a social point of view also based upon certain socio-economic parameters that were included in determining the overall vulnerability of each Mandal in a coastal district (a Mandal represents a group of villages and towns) include: population, senior citizens, women, children under different age groups, type of housing, income level, cyclone shelters, hospitals and medical centres, schools and caste based population. The study is about scenarios that could happen if global warming and the predicted intensification of TCS actually occur as predicted by some numerical models

    The mineral composition of five insects as sold for human consumption in Southern Africa

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    Edible insects have been proposed as an alternative protein source that is economically and  environmentally preferable to livestock, and certain species may be high in nutrients that benefit human health. We present data describing the mineral content of five edible insects as sold in South Africa and Zimbabwe. We report high variation between and within species, and note that these insects contain significant quantities of potentially beneficial, and potentially harmful, micronutrients. Two caterpillars were notably high in Fe and Zn, which are important nutrients for combating iron deficiency anemia. Na content varied both between and within species, suggesting that some sellers add quantities of salt that could be harmful to health. Mn levels were high in edible termites. We concluded that caterpillars can be promoted as nutrient rich foods in southern Africa; that added salt should be limited in commercial products; and that further research is required to determine whether common serving sizes of termites may put consumers in danger of manganese poisoning. Key words: Edible insects, nutrition, mineral composition, micronutrients, Lepidoptera.Abbreviation: DALYs, Disability-adjusted life years; Na, sodium; K, potassium; Ca, calcium; Mg, magnesium; Al, aluminium; P, phosphorus; S, sulphur; Cu, copper; Fe, iron; Mn, manganese; Zn, zinc; DRI, daily recommended intake

    PO and ID BCG vaccination in humans induce distinct mucosal and systemic immune responses and CD4(+) T cell transcriptomal molecular signatures.

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    Protective efficacy of Bacillus Calmette-Guérin (BCG) may be affected by the methods and routes of vaccine administration. We have studied the safety and immunogenicity of oral (PO) and/or intradermal (ID) administration of BCG in healthy human subjects. No major safety concerns were detected in the 68 healthy adults vaccinated with PO and/or ID BCG. Although both PO and ID BCG could induce systemic Th1 responses capable of IFN-γ production, ID BCG more strongly induced systemic Th1 responses. In contrast, stronger mucosal responses (TB-specific secretory IgA and bronchoalveolar lavage T cells) were induced by PO BCG vaccination. To generate preliminary data comparing the early gene signatures induced by mucosal and systemic BCG vaccination, CD4(+) memory T cells were isolated from subsets of BCG vaccinated subjects pre- (Day 0) and post-vaccination (Days 7 and 56), rested or stimulated with BCG infected dendritic cells, and then studied by Illumina BeadArray transcriptomal analysis. Notably, distinct gene expression profiles were identified both on Day 7 and Day 56 comparing the PO and ID BCG vaccinated groups by GSEA analysis. Future correlation analyses between specific gene expression patterns and distinct mucosal and systemic immune responses induced will be highly informative for TB vaccine development.Mucosal Immunology advance online publication 30 August 2017; doi:10.1038/mi.2017.67

    Mitigation of flooding and cyclone hazard in Orissa, India

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    Storm surges generated by the strong tangential wind stressesand normal atmospheric pressure gradients at the sea surface due to tropical cyclones (TC"S)have been studied with the goal of detecting any significant and systematic changes due to climatechange. Cyclone and storm surge data for the 19th and 20th centuries for the Bay of Bengalcoast of the state of Orissa in India are available to varying degrees of quality and detail,the data being more scientific since the advent of the India Meteorological Department in 1875.Based on more precise data for the period 1971 to 2000, statistical projections have been madeon the probable intensities of tropical cyclones for various return periods. The super cyclone ofOctober 29, 1999 (SC1999) appears to have a return period of about 50 years. The cyclones of1831, 1885 and possibly the one in 1895 could have been super cyclones. During the 19th century,there were 72 flooding events associated with cyclones, whereas in the 20th century therewere only 56 events. There was no observational evidence to suggest that there was an increaseeither in the frequency or intensity of cyclones or storm surges on the coast of Orissa. However,the impact of cyclones and surges is on the increase due to increase of population and coastal infrastructure

    A thermally stable {FeNO}(8) complex: properties and biological reactivity of reduced MNO systems

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    Reduced nitrogen oxide ligands such as NO−/HNO or nitroxyl participate in chemistry distinct from nitric oxide (NO). Nitroxyl has been proposed to form at heme centers to generate the Enemark–Feltham designated {FeNO}8 system. The synthesis of a thermally stable {FeNO}8 species namely, [Co(Cp*)2][Fe(LN4)(NO)] (3), housed in a heme-like ligand platform has been achieved by reduction of the corresponding {FeNO}7 complex, [Fe(LN4)(NO)] (1), with decamethylcobaltocene [Co(Cp*)2] in toluene. This complex readily reacts with metMb, resulting in formation of MbNO via reductive nitrosylation by the coordinated HNO/NO−, which can be inhibited with GSH. These results suggest that 3 could serve as a potential HNO therapeutic. Spectroscopic, theoretical, and structural comparisons are made to 1 and the {CoNO}8 complex, [Co(LN4)(NO)] (2), an isoelectronic analogue of 3

    Does early linear growth failure influence later school performance? A cohort study in Karonga district, northern Malawi.

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    INTRODUCTION: Stunting or linear growth retardation in childhood is associated with delayed cognitive development due to related causes (malnutrition, illness, poor stimulation), which leads to poor school outcomes at later ages, although evidence of the association between the timing and persistence of stunting and school outcomes within the sub-Saharan African context is limited. METHODS: Anthropometric data around birth (0-4 months), early (11-16 months) and late childhood (ages 4-8 years) along with school outcomes up until the age of 11 were analysed for a cohort of 1,044 respondents, born between 2002-2004 in Karonga district, northern Malawi. The schooling outcomes were age at school enrolment, grade repetition in Standard 1 and age-for-grade by age 11. Height-for-Age Z-scores (HAZ) and growth trajectories were examined as predictors, based on stunting (<-2SD HAZ) and on trajectories between early and late childhood (never stunted, improvers, decliners or persistently stunted). Multinomial and logistic regression were used to estimate the association between stunting/trajectories and schooling, adjusted for socioeconomic confounders. RESULTS: The effects of stunting on schooling were evident in early childhood but were more pronounced in late childhood. Children who were stunted in early childhood (9.3%) were less likely to be underage at enrolment, more likely to repeat Standard 1 and were 2-3 times more likely to be overage for their grade by the age of 11, compared to their non-stunted peers. Those persistently stunted between early and late childhood (7.3%) faced the worst consequences on schooling, being three times as likely to enrol late and 3-5 times more likely to be overage for their grade by the age of 11, compared to those never stunted. Compared to improvers, those persistently stunted were three times as likely to be overage by two or more years by the age of 11, with no effect on enrolment or repetition. CONCLUSION: Our findings confirm the importance of early childhood stunting on schooling outcomes and suggest some mitigation by improvements in growth by the age of starting school. The nutritional and learning needs of those persistently stunted may need to be prioritised in future interventions
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