1,173 research outputs found
Meta-modes of learning that support and influence the millennial student’s holistic learning experience at an academic institute in South Africa
Teaching in diverse ways to a diverse generation, globally, academic institutes must ensure that learning is responsive, appropriate and supportive of cohorts in emerging and involving modes of learning. However, the pedagogy, processes and learning methods are of paramount importance for this diverse student generation in order to recognise subsequent cohorts for whom motivation and engagement in a holistic learning experience for millennial students could be maximised. While it has been recognised that current learning practices may not address the holistic learning experience of the millennial student, the purpose of this study, through the adoption of the Student-Owned Learning-Engagement (SOLE) model, its nine elements and 42 meta-modes of learning, is to investigate and identify the confluence of meta-modes of learning that could support and influence the millennial student’s holistic learning experience. In response to the needs of aspiring millennial learners, data were obtained from 69 students and 15 teachers by means of a self-administrated questionnaire. A comparison was drawn between the theories that the millennials preferred meta-modes of learning and the modes of teaching that the teachers had adopted. Hence, this study offers strategies to improve the holistic experience of learning. This is performed in a manner that support new empirical emerging and involving modes of learning for the millennial student
Evaluation of artificially contaminated fish with formaldehyde under laboratory conditions and exposure assessment in freshwater fish in Southern Bangladesh
Quantitative Risk Assessment for Formalin Treatment in Fish Preservation: Food Safety Concern in Local Market of Bangladesh
AbstractIn Bangladesh, fishes are adulterated by hazardous chemicals at different steps from farm to consumers. Formalin (FA) is reported to be frequently added as preservative either by dipping or spraying to the fresh fishes by the fish traders while transporting to domestic marketing chain to prevent spoilage and extend shelf life. Thus, the objective of the present study was toconduct quantitative risk assessment (QRA) for formalin treated fish in Bangladesh. The probabilistic QRA of formalin treated fish was performed based on available secondary data. Available data on concentration of formalin in fish, daily fish consumption by the consumer and their body weight were used to estimate the risk of residual formalin to the consumers. Based on the data, three different scenarios (average consumption, two and four times of average consumption considered as scenarios 1, 2 and 3, respectively) were used for exposure analysis using @Risk program version 6.0.FA concentration in consumedfresh and cooked (boiling) fish was 5.34x10-02 and 2.340x10-02 (mg/kg bw/day), respectively and national average fish consumption was 200g/day. QRA reveals that FA intake under scenario1 and 2 was lower than acceptable daily intake (ADI 0.2mg/kg bw/day set by the United States Environmental Protection Agency) thus lower risk observed for both fresh and cooked fish. However, scenario 3 revealed that 0.01% population was at risk (FA intake 0.21mg/kg bw/day higher than ADI) upon the fresh fish consumption, where cooked fish (FA 9.38x10-02 mg/kg bw/day) consumer remains safe at the same scenario. The result confirmed that cooking has significant effect to reduction of formalin. Therefore, probabilistic quantitative risk assessment of formalin treated fish could provide important risk information to the risk manager (government), whether the population is at risk or not? The result could be applied to establish effective risk management strategy in Bangladesh
A manufacturer-buyers integrated inventory model with generic distribution of lead times to deliver equal and/or unequal batch sizes
Although lead time variation is common in practice, integrated single-manufacturer multi-buyer model considering this factor is unavailable in the extant literature. This article considers generic distribution of lead times of delivering equal and/or unequal batch (sub-lot) sizes of a lot in developing a synchronised integrated single-manufacturer multi-buyer model. The batch sizes are assumed to be in geometric series. The variables considered in the model are the smallest batch size, total number of batches and number of unequal batch sizes delivered from the manufacturer to buyers. The smallest batch sizes delivered to the buyers are bounded below by 1 and above by the capacity of the transport vehicle. The minimal total cost solution technique to the model is derived by the method of differentiation. Significant minimal total cost reductions by the synchronised flow is illustrated through solutions to some numerical example problems. Sensitivity analyses on increasing costs of transportation, shortage, inventory and increasing mean lead times upon the optimal solution have been performed
Environmental Life Cycle Assessment of Alternative Fuels for Western Australia’s Transport Sector
Alternative fuels for the transport sector are being emphasized due to energy security and environmental issues. Possible alternative fuel options need to be assessed to realize their potential to alleviate environmental burdens before policy formulations. Western Australia (WA) is dominated by private cars, accounting for around 72% vehicles with 87% of those using imported gasoline, and resulting in approximately 14% of greenhouse gas (GHG) emissions from the transport sector. There is an urgent need for WA to consider alternative transport fuels not only to reduce the environmental burden but also to avoid future energy security consequences. This study assesses the environmental life cycle assessment (ELCA) of transport fuel options suitable for WA. The study revealed that ethanol (E65), electric (EV) and plug-in electric vehicle (PHEV) options can decrease global warming potential (GWP) by 40%, 29% and 14%, respectively, when compared to gasoline. The EV and PHEV also performed better than gasoline in the fossil fuel depletion (FFD) and water consumption (WC) impact categories. Gasoline, however, demonstrated better environmental performance in all the impact categories compared to hydrogen and that was mainly due to the high electricity requirement during the production of hydrogen. The use of platinum in hydrogen fuel cells and carbon fibre in the hydrogen tank for hydrogen fuel cell vehicles (HFCV) and Li-ion battery for EVs are the most important sources of environmental impacts. The findings of the study would aid the energy planners and decision makers in carrying out a comparative environmental assessment of the locally-sourced alternative fuels for WA
Resource metabolism of the construction sector : an application of material and exergy flow analysis
Ésta tesis tiene como objetivo evaluar el consumo de recursos del sector de la construcción, los residuos y las emisiones generadas por el sector. Ésto está motivado por el hecho de que el sector de la construcción es responsable de una gran cantidad de consumo de recursos y representa casi el 9% el valor bruto añadido al producto interno bruto del mundo. La evaluación considera la perspectiva del ciclo de vida, desde la extracción de materias primas, a través de la construcción y fabricación de productos, materiales de transporte, la construcción, la generación de residuos de demolición, el transporte de residuos, el tratamiento y disposición final. El objetivo es identificar las oportunidades y mejorar los criterios de selección de materiales, el procesado, la reutilización y el reciclado para el uso sostenible de los recursos. Debido a la complejidad de los sistemas de edificios e infraestructuras, compuestas de muchos componentes que interactúan, siempre es difícil llevar a cabo una contabilidad de los recursos precisos dentro de éste sector. En esta perspectiva, el concepto de análisis de flujo de materiales y la evaluación del ciclo de vida (ACV), y el análisis de exergía se tratan como herramientas de contabilidad de recursos y se centra en sus aplicaciones en el sector de la construcción. Además del análisis sectorial, ésta tesis, también analiza la eficiencia de los procesos de fabricación y el ciclo de vida completo de los productos con base a exergía. Todos los procesos y los productos seleccionados son relevantes para el sector de la construcción, y éste análisis tiene como objetivo proporcionar conocimientos de despersonalización en el uso de materiales del sector. En el capítulo 1, se expone el marco teórico en que los análisis de flujo de exergía y los materiales se utilizan en la evaluación del metabolismo de los recursos del sector de la construcción, que destacan la importancia de éste sector en términos de flujos de recursos y la generación de residuos y emisiones. Éste capítulo, también introduce la eficiencia exérgica y herramientas de evaluación del ciclo de vida exergéticos, que explica las limitaciones del análisis de la energía y el ACV, y cómo la aplicación de éstos métodos a base de exergía puede ofrecer mejores perspectivas sobre la eficiencia del uso de los recursos en los procesos de fabricación en toda la vida de los productos, respectivamente. La Ecología Industrial, se presenta al introducir el enfoque basado en los sistemas y el marco termodinámico en el que el sector de la construcción se analiza en este estudio. El capítulo 2, presenta los resultados de los análisis de flujo de materiales y exergía del sector de la construcción catalana en el año 2001. En ese momento, Cataluña tenía un adicional de 52 millones de toneladas de existencias de materiales para el sector y generaba 7 millones de toneladas de residuos de construcción y demolición, de los cuales sólo el 6,5% son recicladas o regeneradas. El estudio muestra que la fase de fabricación consume la mayor parte de los recursos de energía durante el ciclo de vida del conjunto de los productos, seguidos de transporte de materiales, que representa el 57% y el 4% del consumo de exergía, respectivamente. Se señala que la mejora en la selección de materiales, tecnologías de fabricación y diseño para el desmontaje, conduce a la sostenibilidad del sector, para conseguir una mejora de la eficiencia del uso de recursos. En el capítulo 3, se menciona el rendimiento exergético de los procesos de producción, tanto en el proceso de producción primaria como secundaria (reciclaje), de los materiales de construcción que se calcula, con el fin de evaluar la calidad de los materiales, las pérdidas de exergía, y el potencial de mejora de procesos. Ésto sirve para cuantificar el potencial de mejora de los procesos de fabricación actuales que abordan las deficiencias de fabricación de los nueve principales materiales de construcción no renovables: aluminio, acero, cobre, cemento, hormigón, cerámica, vidrio, polipropileno y cloruro de polivinilo. La Eficiencia Exergía basada en la segunda ley de la termodinámica es determinada con el fin de comparar la eficiencia exergía teórica y la eficiencia exergía del proceso real. La gran diferencia entre los requisitos teóricos y empíricos de exergía en los procesos de fabricación sugiere que las oportunidades para una mejor utilización de exergía industrial todavía existen, pero requieren un diseño y mejoras en la tecnología. Los resultados demuestran que los recursos se utilizan de manera más eficiente en los procesos de reciclaje, en comparación con los procesos de fabricación primaria. En esta tesis se presenta una teoría (capítulo 4) para determinar como de eficientemente se utilizan los recursos en las aplicaciones de la construcción, utilizando la metodología de análisis del ciclo de vida exergético desde un enfoque universal. Esto incluye la extracción de materias primas, la fabricación de resina y de gestión de las etapas del ciclo de vida de los residuos al final de su vida. La irreversibilidad durante el ciclo de vida completo permite evaluar el grado de perfección termodinámica de los procesos de producción y llevar a cabo la evaluación de la cadena de producción entera. Ciclo de vida global de la eficiencia exérgica de polipropileno y cloruro de polivinilo se cuantifica en 27,1% y 9,3%, respectivamente, que se caracteriza por una baja eficiencia en la fabricación y los procesos de reciclaje para ambos materiales. Desde el punto de vista de la conservación de recursos, el reciclado mecánico se ha sugerido como la opción viable para la gestión de residuos de plástico al final de su vida, ya que los materiales de bucles vuelven a su ciclo de vida original y reduce las aportaciones de recursos primarios en la producción.This thesis aims to assess the resource consumption of the construction sector, and the wastes and emissions generated by the sector. This is motivated by the fact that the construction sector is responsible for large amounts of resource consumption and represents nearly 9% gross value added to the world's gross domestic product. The assessment considers the life cycle perspective from raw material extraction, through construction product manufacturing, material transport, construction and demolition waste generation, to waste transport, treatment, and final disposal. The aim is to pinpoint the opportunities for improved material selection criteria, processing, reuse, and recycling for sustainable resource use. Due to the system complexity of buildings and infrastructure, composed of many interacting components, it is always challenging to undertake an accurate resource accounting within this sector. In this perspective, the concepts of material flow analysis (MFA), life cycle assessment (LCA), and exergy analysis (ExA) are discussed as resource accounting tools focusing on their applications in the construction sector. Apart from sectoral analysis, this thesis also analyzes the efficiency of manufacturing processes and products' complete life cycle based on exergy. All the processes and products selected are relevant for the construction sector, and this analysis aims to provide deper insights into sectoral material use. Chapter 1 details the theoretical framework under which exergy and material flow analyses are used in assessing the resource metabolism of the construction sector highlighting the importance of this sector in terms of resource flows, and generation of waste and emissions. This chapter also introduces the exergy efficiency and exergetic life cycle assessment (ELCA) tools, explaining the limitations of energy analysis and LCA, and how the application of these exergy-based methods can provide better insights into resource use efficiency in manufacturing processes and throughout the products' life, respectively. Industrial ecology (IE) is presented to introduce the systems-based approach and thermodynamic framework on which of the construction sector is analyzed in this study. Chapter 2 presents the results of material and exergy flow analyses of the Catalan construction sector for the year 2001. In 2001, Catalonia had an additional 52 million tonnes of material stock to the sector and generated 7 million tonnes of construction and demolition waste (CDW) of which only 6.5% were recycled or reclaimed. The study shows that manufacturing stage consumes the largest fraction of energy resources during the products' whole lifecycle followed by material transport, accounting for 57% and 4% of exergy use, respectively. It is pointed out that improvement in material selection, manufacturing technologies, and design for disassembly lead to sustainability of the sector delivering improved resource use efficiency. In chapter 3, the exergetic efficiency of the production processes, both primary and secondary (recycling) production process, of construction materials is calculated in order to assess material quality, exergy losses, and process improvement potentials. This serves to quantify the improvement potentials for present manufacturing processes addressing the manufacturing inefficiencies of nine major non-renewable construction materials: aluminum, steel, copper, cement, concrete, ceramic, glass, polypropylene (PP), and polyvinyl chloride (PVC). Exergy efficiency based on the second law of thermodynamics is determined in order to compare the theoretical exergy efficiency and the real-process exergy efficiency. The large difference between theoretical and empirical exergy requirements in manufacturing processes suggests that opportunities for better industrial exergy utilization still exist but require design and/or technology improvements. The results demonstrate that resources are utilized more efficiently in recycling processes compared to primary manufacturing processes. This thesis has presented an effort (chapter 4) to pinpoint how efficiently resources are used in the construction applications, using exergetic life cycle assessment methodology in a cradle-to-grave life cycle approach. This included raw material extraction, resin manufacturing, and end-of-life waste management life-cycle stages. The irreversibility during the complete life cycle allows to evaluate the degree of thermodynamic perfection of the production processes and to conduct the assessment of the whole process chain. Overall life cycle exergy efficiency of PP and PVC is quantified 27.1% and 9.3%, respectively, characterized by a low efficiency of manufacturing and recycling processes for both materials. From resource conservation point of view, mechanical recycling has been suggested as the viable option for end-of-life plastic waste management, since it loops materials back directly into new life cycle and reduces primary resource inputs in the production
Managing ‘difference’: understanding age diversity in practice
This article explores how human resource (HR) managers discuss, classify and justify age diversity as both a concept and practice within the UK. The findings from 33 in-depth interviews with HR managers reveal difficulty in translating age diversity as an abstract managerial concept into workfloor policy and practice. Whilst the managers sought to emphasise the role of culture in promoting diversity, there was a lack of evidence that this related to workfloor equality or activities that proactively challenge discrimination. Moreover, there was confusion over classifying older workers as ‘diverse’, and risking possible discriminatory practices which marginalised both the older workers and other employees. The conclusions discuss how the ambiguous concept of ‘difference’ which lies at the basis of understanding both diversity and discrimination caused tension when implementing older worker strategies, and how policy makers must provide clear measures concerning the intent, objectives and definitions surrounding age equality. It is argued that a move towards an action model of discrimination management may help to create a framework where diversity and discrimination can be mutually addressed
Human papillomavirus types 16, 18, and 31 serostatus and prostate cancer risk in the Prostate Cancer Prevention Trial
Since human papillomavirus (HPV) infection was first identified as a risk factor for cervical cancer, several seroepidemiologic and tissue-based studies have investigated HPV in relation to prostate cancer, another common genitourinary malignancy, with mixed results. To further inform this potential association, we conducted a large, prospective investigation of HPV types 16, 18, and 31 in relation to risk of prostate cancer in the Prostate Cancer Prevention Trial (PCPT). Cases were a sample of men diagnosed with prostate cancer after visit 2 or on their end-of-study biopsy (n=616). Controls were men not diagnosed with prostate cancer during the trial or on their end-of-study biopsy (n=616). Controls were frequency-matched to cases by age, treatment arm, and family history of prostate cancer. Sera from visit 2 were tested for IgG antibodies against HPV-16, -18 and -31. No associations were observed for weak or strong HPV-16 (odds ratio (OR) = 0.94, 95% confidence interval (CI): 0.53–1.64, and OR=1.07, 95% CI: 077–1.48, respectively), HPV-18 (OR=0.75, 95% CI: 0.27–2.04, and OR=0.87, 95% CI: 0.47–1.63) or HPV-31 seropositivity (OR=0.76, 95% CI: 0.45–1.28, and OR=1.15, 95% CI: 0.80–1.64) and risk of prostate cancer. Considering this finding in the context of the HPV and prostate cancer literature, HPV does not appear to be associated with risk of prostate cancer, at least by mechanisms proposed to date, and using epidemiologic designs and laboratory techniques currently available
Post epidemic giardiasis and gastrointestinal symptoms among preschool children in Bergen, Norway. A cross-sectional study
<p>Abstract</p> <p>Background</p> <p>A surprisingly low number of children became ill with giardiasis during the large waterborne outbreak of <it>Giardia lamblia </it>in Bergen, Norway during autumn 2004. The aim of the present study was to evaluate the prevalence of giardiasis among exposed children one year after an outbreak and compare faecal carriage of <it>Giardia </it>and abdominal symptoms among exposed versus unexposed children one year after the epidemic.</p> <p>Methods</p> <p>Children between 1 and 6 years old were recruited from the local health care centres in Bergen municipality in the period between June 2005 and January 2006. One faecal sample per child was collected and examined for presence of <it>Giardia </it>with a rapid immunoassay antigen test, and parents were asked to answer a questionnaire. A total of 513 children participated, 378 in the group exposed to contaminated water, and 135 in the in the group not exposed.</p> <p>Results</p> <p>In the exposed group eleven children had been treated for giardiasis during the epidemic and none in the unexposed group. <it>Giardia </it>positive faecal tests were found in six children, all in the exposed group, but the difference between the groups did not reach statistical significance. All six <it>Giardia </it>positive children were asymptomatic. No differences were found between the groups regarding demographic data, nausea, vomiting, different odour from stools and eructation. However, the reported scores of abdominal symptoms (diarrhoea, bloating and stomach ache) during the last year were higher in the exposed group than in the unexposed group.</p> <p>Conclusions</p> <p>A low prevalence of asymptomatic <it>Giardia </it>infection (1.7%) was found among exposed children around one year after the epidemic (1.2% overall prevalence in the study). In the present setting, pre-school children were therefore unlikely to be an important reservoir for continued transmission in the general population.</p
Accuracy assessment of Precise Point Positioning with multi-constellation GNSS data under ionospheric scintillation effects
GPS and GLONASS are currently the Global Navigation Satellite Systems (GNSS) with full 16 operational capacity. The integration of GPS, GLONASS and future GNSS constellations can 17 provide better accuracy and more reliability in geodetic positioning, in particular for kinematic 18 Precise Point Positioning (PPP), where the satellite geometry is considered a limiting factor to 19 achieve centimeter accuracy. The satellite geometry can change suddenly in kinematic 20 positioning in urban areas or under conditions of strong atmospheric effects such as for instance 21 ionospheric scintillation that may degrade satellite signal quality, causing cycle slips and even 22 loss of lock. Scintillation is caused by small scale irregularities in the ionosphere and is 23 characterized by rapid changes in amplitude and phase of the signal, which are more severe in 24 equatorial and high latitudes geomagnetic regions. In this work, geodetic positioning through the 25 PPP method was evaluated with integrated GPS and GLONASS data collected in the equatorial 26 region under varied scintillation conditions. The GNSS data were processed in kinematic PPP 27 mode and the analyses show accuracy improvements of up to 60% under conditions of strong 28 scintillation when using multi-constellation data instead of GPS data alone. The concepts and 29 analyses related to the ionospheric scintillation effects, the mathematical model involved in PPP 30 with GPS and GLONASS data integration as well as accuracy assessment with data collected 31 under ionospheric scintillation effects are presented
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