433 research outputs found

    Examining the relationship between abstract thinking ability and academic performance in object oriented programming : a psychometric and theoretical analysis of student capacity

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    Published ArticleAbstract reasoning involves flexible thinking as well as solving problems creatively and logically. Evidence suggest that especially first year students that undertake Information Technology studies at institutions of higher education, find it challenging to successfully comprehend concepts regarding object oriented programming (OOP). This study is based on the hypothetical premise that student performance regarding OOP can be linked to the abstract thinking ability of the particular student because of the highly abstract nature of OOP concepts. A comparison between psychometric test results gauging abstract thinking abilities of students and student performance in OOP are also presented and argued

    Microcystis aeruginosa: source of toxic microcystins in drinking water

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    Cyanobacteria are one of the earth's most ancient life forms. Evidence of their existence on earth, derived from fossil records, encompasses a period of some 3.5 billion years in the late Precambrian era. Cyanobacteria are the dominant phytoplanton group in eutrophic freshwater bodies worldwide. They have caused animal poisoning in many parts of the world and may present risks to human health through drinking and recreational activity. Cyanobacteria produce two main groups of toxin namely neurotoxins and peptide hepatotoxins. They were first characterized from the unicellular species, Microcystis aeruginosa, which is the most common toxic cyanobacterium in eutrophic freshwater. The association of environmental parameters with cyanobacterial blooms and the toxicity of microcystin are discussed. Also, the synthesis of the microcystins, as well as the mode of action, control and analysis methods for quantitation of the toxin is reviewed. Key Words: Cyanobacteria, microcystins, mcyB gene, PCR-RFLP. African Journal of Biotechnology Vol.3(3) 2004: 159-16

    Transplacental haemorrhage and the mode of placental delivery

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    A study was undertaken to determine whether the incidence and degree of transplacental haemorrhage would be affected by the following methods of placental  delivery: Brandt-Andrew's manoeuvre, spontaneous or natural delivery, and manual removal. A total of 445 patients were studied, 10-1% of whom were found to have had evidence of a clinically significant foeto-maternal haemorrhage. Except for manual removal, foeto-maternal transfer was not affected by the method of handling of the third stage

    Obstetric spinal hypotension: Preoperative risk factors and the development of a preliminary risk score – the PRAM score

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    Background. Obstetric spinal hypotension is a common and important problem during caesarean delivery. Identifying patients at risk for hypotension may guide clinical decision-making and allow timeous referral.Objective. Using preoperative risk factors, to develop a simple scoring system to predict systolic hypotension.Methods. This prospective, single-centre, observational study of patients undergoing elective or urgent caesarean delivery assessed body mass index, baseline heart rate, baseline mean arterial pressure (MAP), maternal age, urgency of surgery (elective v. non-elective) and preoperative haemoglobin concentration as predictors of spinal hypotension (systolic blood pressure <90 mmHg). We used empirical cut-point estimations in a logistic regression model to develop a scoring system for prediction of hypotension.Results. From 504 eligible patients, preoperative heart rate (odds ratio (OR) 1.02, 95% confidence interval (CI) 1.00 - 1.03; p=0.012), preoperative MAP (OR 0.97, 95% CI 0.95 - 0.98; p<0.001) and maternal age (OR 1.05, 95% CI 1.02 - 1.08; p=0.002) were found to be predictors of hypotension. We derived a preliminary scoring system (pulse rate >90 bpm, age >25 years, MAP <90 mmHg – the PRAM score) for the prediction of systolic hypotension following obstetric spinal anaesthesia. Patients with three factors had a 53% chance of developing hypotension, compared with the overall incidence of 30%. The PRAM score showed good discrimination, with a c-statistic of 0.626 (95% CI 0.576 - 0.676) and good calibration.Conclusions. Preoperative heart rate, preoperative MAP and maternal age were predictive of hypotension in elective and emergency caesarean delivery. The PRAM score shows promise as a simple, practical means to identify these patients preoperatively, but requires prospective validation

    Photosynthetic characteristics of five high light and low light exposed microalgaea as measured with 14C-uptake and oxygen electrode techniques

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    #Tetraselmis suecica, #Thalassiosira pseudonana, #Chaetoceros calcitrans, #Isochrysis galbana et #Microcystis sp.$ ont été utilisées pour déterminer leurs capacités d'adaptation et pour tester les différences entre les deux méthodes de mesure. Les cultures avaient été exposées à un éclairement fort (HL) ou à un éclairement faible (LL) pendant deux jours avant l'expérience. L'efficacité de la conversion de la lumière (...) et l'activité photosynthétique spécifique maximale par unité de chlorophylle (...) ont été généralement plus élevées pour les cultures LL. Les divers paramètres photosynthétiques mesurés par la méthode de l'électrode à oxygène ont été différents de ceux obtenus par celle du 14C. Les importantes différences de quotient photosynthétique (O2/CO2), observées aussi bien entre cultures HL et LL d'une même espèce qu'entre espèces différentes, soulignent la difficulté de convertir les productions d'oxygène en assimilation de carbone. (D'après résumé d'auteur

    Dermal fibroblasts derived from fetal and postnatal humans exhibit distinct responses to insulin like growth factors

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    <p>Abstract</p> <p>Background</p> <p>It has been well established that human fetuses will heal cutaneous wounds with perfect regeneration. Insulin-like growth factors are pro-fibrotic fibroblast mitogens that have important roles in both adult wound healing and during development, although their relative contribution towards fetal wound healing is currently unknown. We have compared responses to IGF-I and -II in human dermal fibroblast strains derived from early gestational age fetal (<14 weeks) and developmentally mature postnatal skin to identify any differences that might relate to their respective wound healing responses of regeneration or fibrosis.</p> <p>Results</p> <p>We have established that the mitogenic response of fetal cells to both IGF-I and -II is much lower than that seen in postnatal dermal fibroblasts. Further, unlike postnatal cells, fetal cells fail to synthesise collagen in response to IGF-I, whereas they do increase synthesis in response to IGF-II. This apparent developmentally regulated difference in response to these related growth factors is also reflected in changes in the tyrosine phosphorylation pattern of a number of proteins. Postnatal cells exhibit a significant increase in phosphorylation of ERK 1 (p44) in response to IGF-I and conversely the p46 isoform of Shc on IGF-II stimulation. Fetal cells however only show a significant increase in an unidentified 100 kDa tyrosine-phosphorylated protein on stimulation with IGF-II.</p> <p>Conclusion</p> <p>Dermal fibroblasts exhibit different responses to the two forms of IGF depending on their developmental maturity. This may relate to the developmental transition in cutaneous wound healing from regeneration to fibrosis.</p

    A review of remote-sensing unmanned aerial vehicles in the mining industry

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    The increased adoption of unmanned aerial vehicles (UAVs) may improve the productivity and costeffectiveness of remote sensing in the mining industry. This review’s objective is to enable stakeholders to identify possible application adoption, improvement, and innovation opportunities. The review merges a building block strategy and practical screening criteria to identify possible avenues of research to answer the review questions. After the screening process, 72 documents were included in the review. Papers were classified into four categories: exploration, development, exploitation, and reclamation. Fifteen applications were identified, the majority of which were in the exploration phase. The most often researched applications were topographic surveys, reclamation monitoring, and slope management. From the two UAV types identified, multi-rotor vehicles were the most favoured for all applications. From the eight remote sensing techniques identified, photogrammetry was the one most often used. Other techniques were limited because of complexity, cost, or the incompatibility of sensors and UAVs. The review was limited to published papers in academic journals. Future studies could aim to include empirical data on the latest UAV applications used in the mining industry.https://journals.co.za/journal/saimmam2023Graduate School of Technology Management (GSTM
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