2,176 research outputs found

    Technology transfer practices and strategies: Issues for Nigerian construction organisations and for research

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    Technology transfer is increasingly being seen as an important issue for economic development and growth. Arguably, this is why developed and especially developing countries are very keen on technology transfer. However, there are those that contend that organisations in the Nigerian construction industry are not as engaged in technology transfer as many would like, and that potential benefits of doing so are not realized. In the same vein, the challenges that confront construction organisations in Nigeria in terms of technology transfer have received very little empirical studies. This paper, therefore, presents a thorough review of literature on strategic issues and choices that Nigerian construction organisations face in grappling with technology transfer, together with associated challenges. Consideration is also given to what technology transfer actually means to such organisations, and how this is viewed in line with other terms such as innovation. The paper argues and concludes that the challenges that confront construction organisations in Nigeria are multifaceted and likely to impact on their strategic choices. In the same vein, it is also argued that these have implications for researchers attempting to investigate technology transfer practices and strategies in construction organisations in Nigeria in terms of their choice of research strategy and design

    Laser light on the mycoflora content in maize seeds

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    Laser light has many applications in agriculture, but there is still much work to provide scientific evidence of its potential use as an alternative for the control of diseases originating in the seed, especially for fungi that are internal. In this study, we investigated the effects of low intensity laser irradiation on the mycoflora content in maize seeds. Five irradiation times (30, 60, 180, 300 and 600 s) and two intensity levels (I1 = 16.3 e and I2 = 4.6 mW/cm2) were applied by using a diode laser (λ= 655 nm and power of 27.4 mW). Consequently, the laser irradiation significantly diminished the quantity of seeds infected with Fusarium spp. fungi. The combination of I1 and I2, at 5 min of irradiation time, diminished (p < 0.05) the quantity of infected seeds with Fusarium spp. up to 61.11% when compared with the control seed (no irradiation). From these results, we concluded that low intensity laser irradiation could be an alternative method to control seed transmitted diseases in maize seed.Key words: Zea mays L., diode laser, low intensity laser, fungi, Fusarium

    Neutrino induced reactions related to the Μ\nu-process nucleosynthesis of 92{}^{92}Nb and 98{}^{98}Tc

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    It has recently been proposed that 4192{}^{92}_{41}Nb and 4398{}^{98}_{43}Tc may have been formed in the Îœ\nu-process. We investigate the neutrino induced reactions related to the Îœ\nu-process origin of the two odd-odd nuclei. The main neutrino reactions for 4192{}^{92}_{41}Nb are the charged-current (CC) 92^{92}Zr(Îœe,e−\nu_e,e^{-})92^{92}Nb and the neutral-current (NC) 93^{93}Nb(Îœ(Μˉ),Îœâ€Č(Μˉ)â€Č{\nu} ({\bar \nu}), {\nu}^{'} ({\bar \nu})^{'} n)92^{92}Nb reactions. The main reactions for 4398{}^{98}_{43}Tc, are the CC reaction 98^{98}Mo(Îœe,e−\nu_e,e^-)98^{98}Tc and the NC reaction 99^{99}Ru(Îœ(Μˉ),Îœâ€Č(Μˉ)â€Č{\nu} ({\bar \nu}), {\nu}^{'} ({\bar \nu})^{'} p)98^{98}Tc. Our calculations are carried out using the quasi-particle random phase approximation. Numerical results are presented for the energy and temperature dependent cross sections. Since charge exchange reactions by neutrons may also lead to the formation of 4192{}^{92}_{41}Nb and 4398{}^{98}_{43}Tc, we discuss the feasibility of the 92^{92}Mo(n,p)92^{92}Nb and 98^{98}Ru(n,p)98^{98}Tc reactions to produce these nuclei.Comment: 21 pages, 8 figure

    Curriculum Infusion Through Case Studies: Engaging Undergraduate Students In Course Subject Material and Influencing Behavior Change

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    This study investigated infusing health promotion topics into an engineering course via problem-based case studies and lecture to assess student learning and self-reported behavior. Junior-level systems engineering students in two sections participated: one section with 52 students and one with 36. One section received a celebratory drinking case; one received distracted driving case and a lecture about hazardous drinking. Student ability ratings related to the course subject matter generally improved with both cases. The lecture appeared to enhance health promotion knowledge. Students self-reported behavior change with both cases. Case studies as a form of curriculum infusion for health promotion topics show promise. The use of case studies overall was well-received by students and coupled with lecture material can increase student health promotion knowledge and behavior change

    Child malaria treatment decisions by mothers of children less than five years of age attending an outpatient clinic in south-west Nigeria: an application of the PEN-3 cultural model

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    <p>Abstract</p> <p>Background</p> <p>Using the PEN-3 cultural model, this study sought to understand mothers treatment decisions about their child febrile illness by examining positive health beliefs and practices held by mothers, examine existential (unique) practices that are indigenous to mothers and have no harmful health consequences, and explore negative beliefs and practices that limit recommended responses to febrile illness in children.</p> <p>Methods</p> <p>This qualitative study was conducted in the paediatric section of an outpatient clinic in south-west Nigeria. A total of 123 mothers with children less than five years of age with febrile illness diagnosed as malaria by physicians were individually interviewed on their treatment-seeking practices prior to visiting the clinic and their reasons for attendance at the clinic.</p> <p>Results</p> <p>For some mothers interviewed, effective treatment from the clinic for their child's febrile illness, coupled with physician's approach with malaria diagnosis and treatment practices was important in generating positive maternal treatment-seeking responses to child febrile illness. In addition, beliefs related to a child teething highlighted existential decisions with treatment-seeking for child febrile illness in this setting. Finally, the belief that febrile illness is not all that severe despite noticeable signs and symptoms was a concerning negative perception shared by some mothers in this study.</p> <p>Conclusion</p> <p>The findings highlight the need to consider not only the responses that may serve as barriers to effective treatment, but also an acknowledgment of the positive and existential responses that are equally critical in influencing mothers' management of malaria in their children.</p

    Probing Evolutionary Repeatability: Neutral and Double Changes and the Predictability of Evolutionary Adaptation

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    The question of how organisms adapt is among the most fundamental in evolutionary biology. Two recent studies investigated the evolution of Escherichia coli in response to challenge with the antibiotic cefotaxime. Studying five mutations in the beta-lactamase gene that together confer significant antibiotic resistance, the authors showed a complex fitness landscape that greatly constrained the identity and order of intermediates leading from the initial wildtype genotype to the final resistant genotype. Out of 18 billion possible orders of single mutations leading from non-resistant to fully-resistant form, they found that only 27 (1.5x10(-7)%) pathways were characterized by consistently increasing resistance, thus only a tiny fraction of possible paths are accessible by positive selection. I further explore these data in several ways.Allowing neutral changes (those that do not affect resistance) increases the number of accessible pathways considerably, from 27 to 629. Allowing multiple simultaneous mutations also greatly increases the number of accessible pathways. Allowing a single case of double mutation to occur along a pathway increases the number of pathways from 27 to 259, and allowing arbitrarily many pairs of simultaneous changes increases the number of possible pathways by more than 100 fold, to 4800. I introduce the metric 'repeatability,' the probability that two random trials will proceed via the exact same pathway. In general, I find that while the total number of accessible pathways is dramatically affected by allowing neutral or double mutations, the overall evolutionary repeatability is generally much less affected.These results probe the conceivable pathways available to evolution. Even when many of the assumptions of the analysis of Weinreich et al. (2006) are relaxed, I find that evolution to more highly cefotaxime resistant beta-lactamase proteins is still highly repeatable

    Generality of shear thickening in suspensions

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    Suspensions are of wide interest and form the basis for many smart fluids. For most suspensions, the viscosity decreases with increasing shear rate, i.e. they shear thin. Few are reported to do the opposite, i.e. shear thicken, despite the longstanding expectation that shear thickening is a generic type of suspension behavior. Here we resolve this apparent contradiction. We demonstrate that shear thickening can be masked by a yield stress and can be recovered when the yield stress is decreased below a threshold. We show the generality of this argument and quantify the threshold in rheology experiments where we control yield stresses arising from a variety of sources, such as attractions from particle surface interactions, induced dipoles from applied electric and magnetic fields, as well as confinement of hard particles at high packing fractions. These findings open up possibilities for the design of smart suspensions that combine shear thickening with electro- or magnetorheological response.Comment: 11 pages, 9 figures, accepted for publication in Nature Material

    Wet Granular Materials

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    Most studies on granular physics have focused on dry granular media, with no liquids between the grains. However, in geology and many real world applications (e.g., food processing, pharmaceuticals, ceramics, civil engineering, constructions, and many industrial applications), liquid is present between the grains. This produces inter-grain cohesion and drastically modifies the mechanical properties of the granular media (e.g., the surface angle can be larger than 90 degrees). Here we present a review of the mechanical properties of wet granular media, with particular emphasis on the effect of cohesion. We also list several open problems that might motivate future studies in this exciting but mostly unexplored field.Comment: review article, accepted for publication in Advances in Physics; tex-style change

    Critical mutation rate has an exponential dependence on population size for eukaryotic-length genomes with crossover

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    The critical mutation rate (CMR) determines the shift between survival-of-the-fittest and survival of individuals with greater mutational robustness (“flattest”). We identify an inverse relationship between CMR and sequence length in an in silico system with a two-peak fitness landscape; CMR decreases to no more than five orders of magnitude above estimates of eukaryotic per base mutation rate. We confirm the CMR reduces exponentially at low population sizes, irrespective of peak radius and distance, and increases with the number of genetic crossovers. We also identify an inverse relationship between CMR and the number of genes, confirming that, for a similar number of genes to that for the plant Arabidopsis thaliana (25,000), the CMR is close to its known wild-type mutation rate; mutation rates for additional organisms were also found to be within one order of magnitude of the CMR. This is the first time such a simulation model has been assigned input and produced output within range for a given biological organism. The decrease in CMR with population size previously observed is maintained; there is potential for the model to influence understanding of populations undergoing bottleneck, stress, and conservation strategy for populations near extinction
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