Search results for: performance properties

Authors: Javad Taherahmadi, Mohammad Jafarian, Mohammad Naser Asefi

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The global capacity of wind power has dramatically increased in recent years. Therefore, improving the technology of wind turbines to take different advantages of this enormous potential in the power grid, could be interesting subject for scientists. The doubly-fed induction generator (DFIG) wind turbine is a popular system due to its many advantages such as the improved power quality, high energy efficiency and controllability, etc. With an increase in wind power penetration in the network and with regard to the flexible control of wind turbines, the use of wind turbine systems to improve the dynamic stability of power systems has been of significance importance for researchers. Subsynchronous oscillations are one of the important issues in the stability of power systems. Damping subsynchronous oscillations by using wind turbines has been studied in various research efforts, mainly by adding an auxiliary control loop to the control structure of the wind turbine. In most of the studies, this control loop is composed of linear blocks. In this paper, simple adaptive control is used for this purpose. In order to use an adaptive controller, the convergence of the controller should be verified. Since adaptive control parameters tend to optimum values in order to obtain optimum control performance, using this controller will help the wind turbines to have positive contribution in damping the network subsynchronous oscillations at different wind speeds and system operating points. In this paper, the application of simple adaptive control in DFIG wind turbine systems to improve the dynamic stability of power systems is studied and the essential condition for using this controller is considered. It is also shown that this controller has an insignificant effect on the dynamic stability of the wind turbine, itself.

Keywords: almost strictly positive real (ASPR), doubly-fed induction generator (DIFG), simple adaptive control (SAC), subsynchronous oscillations, wind turbine

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Authors: Ying-Yi Laio, Yea-Ru Yang, Yih-Ru Wu, Ray-Yau Wang

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Background: Virtual reality (VR) systems are proved to increase motor performance in stroke and elderly. However, the effects have not been established in patients with Parkinson’s disease (PD). Purpose: To examine the effects of VR based training in improving muscle strength, sensory integration ability and walking abilities in patients with PD by a randomized controlled trial. Method: Thirty six participants with diagnosis of PD were randomly assigned to one of the three groups (n=12 for each group). Participants received VR-based Wii Fit exercise (VRWii group) or traditional exercise (TE group) for 45 minutes, followed by treadmill training for another 15 minutes for 12 sessions in 6 weeks. Participants in the control group received no structured exercise program but fall-prevention education. Outcomes included lower extremity muscle strength, sensory integration ability, walking velocity, stride length, and functional gait assessment (FGA). All outcomes were assessed at baseline, after training and at 1-month follow-up. Results: Both VRWii and TE groups showed more improvement in level walking velocity, stride length, FGA, muscle strength and vestibular system integration than control group after training and at 1-month follow-up. The VRWii training, but not the TE training, resulted in more improvement in visual system integration than the control. Conclusions: VRWii training is as beneficial as traditional exercise in improving walking abilities, sensory integration ability and muscle strength in patients with PD, and such improvements persisted at least for 1 month. The VRWii training is then suggested to be implemented in patients with PD.

Keywords: virtual reality, walking, sensory integration, muscle strength, Parkinson’s disease

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Authors: Gaurav Bhanjana, Ganga Ram Chaudhary, Sandeep Kumar, Neeraj Dilbaghi

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Main sources of endocrine disrupting compounds in the ecosystem are hormones, pesticides, phthalates, flame retardants, dioxins, personal-care products, coplanar polychlorinated biphenyls (PCBs), bisphenol A, and parabens. These endocrine disrupting compounds are responsible for learning disabilities, brain development problems, deformations of the body, cancer, reproductive abnormalities in females and decreased sperm count in human males. Although discharge of these chemical compounds into the environment cannot be stopped, yet their amount can be retarded through proper evaluation and detection techniques. The available techniques for determination of these endocrine disrupting compounds mainly include high performance liquid chromatography (HPLC), mass spectroscopy (MS) and gas chromatography-mass spectrometry (GC–MS). These techniques are accurate and reliable but have certain limitations like need of skilled personnel, time consuming, interference and requirement of pretreatment steps. Moreover, these techniques are laboratory bound and sample is required in large amount for analysis. In view of above facts, new methods for detection of endocrine disrupting compounds should be devised that promise high specificity, ultra sensitivity, cost effective, efficient and easy-to-operate procedure. Nowadays, electrochemical sensors/biosensors modified with nanomaterials are gaining high attention among researchers. Bioelement present in this system makes the developed sensors selective towards analyte of interest. Nanomaterials provide large surface area, high electron communication feature, enhanced catalytic activity and possibilities of chemical modifications. In most of the cases, nanomaterials also serve as an electron mediator or electrocatalyst for some analytes.

Keywords: electrochemical, endocrine disruptors, microscopy, nanoparticles, sensors

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Authors: Hadjer Sadoune, Liza Lamini, Scherazade Krim, Amel Djouadi, Rachida Rihani

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Deep neural networks are highly regarded for their accuracy in predicting intricate fermentation processes. Their ability to learn from a large amount of datasets through artificial intelligence makes them particularly effective models. The primary obstacle in improving the performance of these models is to carefully choose the suitable hyperparameters, including the neural network architecture (number of hidden layers and hidden units), activation function, optimizer, learning rate, and other relevant factors. This study predicts biogas production from real wastewater treatment plant data using a sophisticated approach: hybrid Bayesian optimization with a tree-structured Parzen estimator (BO-TPE) for an optimised deep neural network (DNN) model. The plant utilizes an Upflow Anaerobic Sludge Blanket (UASB) digester that treats industrial wastewater from soft drinks and breweries. The digester has a working volume of 1574 m3 and a total volume of 1914 m3. Its internal diameter and height were 19 and 7.14 m, respectively. The data preprocessing was conducted with meticulous attention to preserving data quality while avoiding data reduction. Three normalization techniques were applied to the pre-processed data (MinMaxScaler, RobustScaler and StandardScaler) and compared with the Non-Normalized data. The RobustScaler approach has strong predictive ability for estimating the volume of biogas produced. The highest predicted biogas volume was 2236.105 Nm³/d, with coefficient of determination (R2), mean absolute error (MAE), and root mean square error (RMSE) values of 0.712, 164.610, and 223.429, respectively.

Keywords: anaerobic digestion, biogas production, deep neural network, hybrid bo-tpe, hyperparameters tuning

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Authors: Omojokun G. Aju, Adedayo O. Sule

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ZigBee wireless sensor and control network is one of the most popularly deployed wireless technologies in recent years. This is because ZigBee is an open standard lightweight, low-cost, low-speed, low-power protocol that allows true operability between systems. It is built on existing IEEE 802.15.4 protocol and therefore combines the IEEE 802.15.4 features and newly added features to meet required functionalities thereby finding applications in wide variety of wireless networked systems. ZigBee‘s current focus is on embedded applications of general-purpose, inexpensive, self-organising networks which requires low to medium data rates, high number of nodes and very low power consumption such as home/industrial automation, embedded sensing, medical data collection, smart lighting, safety and security sensor networks, and monitoring systems. Although the ZigBee design specification includes security features to protect data communication confidentiality and integrity, however, when simplicity and low-cost are the goals, security is normally traded-off. A lot of researches have been carried out on ZigBee technology in which emphasis has mainly been placed on ZigBee network performance characteristics such as energy efficiency, throughput, robustness, packet delay and delivery ratio in different scenarios and applications. This paper investigate and analyse the data accuracy, network implementation difficulties and security challenges of ZigBee network applications in star-based and mesh-based topologies with emphases on its home monitoring application using the ZigBee ProBee ZE-10 development boards for the network setup. The paper also expose some factors that need to be considered when designing ZigBee network applications and suggest ways in which ZigBee network can be designed to provide more resilient to network attacks.

Keywords: home monitoring, IEEE 802.14.5, topology, wireless security, wireless sensor network (WSN), ZigBee

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Authors: Vilma Sasyte, Vilma Viliene, Agila Dauksiene, Asta Raceviciute-Stupeliene, Romas Gruzauskas, Saulius Alijosius

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The eight-week feeding trial was conducted involving 27-wk-old Isa brown laying hens to study the effect of dry extrusion processing on partial reduction in total glucosinolates content of locally produced rapeseed and on productivity and eggs quality parameters of laying hens. Thirty-six hens were randomly assigned one of three treatments (CONTR, AERS and HERS), each comprising 12, individual caged layers. The main composition of the diets was the same, but extruded soya bean seed were replaced with 2.5% of the extruded rapeseed in the AERS group and 4.5 % in the HERS group. Rapeseed was extruded together with faba beans. Due to extrusion process the glucosinolates content was reduced by 7.83 µmol/g of rapeseed. The results of conducted trial shows, that during all experimental period egg production parameters, such as the average feed intake (6529.17 vs. 6257 g/hen/14 day; P < 0.05) and laying intensity (94.35% vs. 89.29; P < 0.05) were statistically different for HERS and CONTR laying hens respectively. Only the feed conversion ratio to produce 1 kg of eggs, kg in AERS group was by 11 % lower compared to CONTR group (P < 0.05). By analysing the effect of extruded rapeseed on egg mass, the statistical differences between treatments were no determined. The dietary treatments did not affect egg weight, albumen height, haugh units, albumen and yolk pH. However, in the HERS group were get eggs with the more intensive yolk color, higher redness (a) and yellowness (b) values. The inclusion of full-fat extruded rapeseed had no effect on egg shell quality parameters, i.e. shell breaking strength, shell weight with and without coat and shell index, but in the experimental groups were get eggs with the thinner shell (P < 0.05). The internal egg quality analysis showed that with higher content of extruded rapeseed (4.5 %) level in the diet, the total cholesterol in the eggs yolk decreased by 1.92 mg/g in comparison with CONTR group (P < 0.05). Eggs laid by hens fed the diet containing 2.5% and 4.5% had increasing ∑PNRR/∑SRR ratio and decreasing ∑(n-6)/∑(n-3) ratio values of eggs yolk fatty acids than in CONTR group. Eggs of hens fed different amount of extruded rapeseed presented an n-6 : n-3 ratio changed from 5.17 to 4.71. The analysis of the relationship between hypocholesteremia/ hypercholesterolemia fatty acids (H/H), which is based on the functional properties of fatty acids, found that the value of it ratio is significant higher in laying hens fed diets supplemented with 4.5% extruded rapeseed than the CONTR group, demonstrating the positive effects of extruded rapeseed on egg quality. The results of trial confirmed that extruded full fat rapeseed to the 4.5% are suitable to replace soyabean in the compound feed of laying hens.

Keywords: egg quality, extruded full-fat rapeseed, laying hens, productivity

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Authors: Anza-Vhudziki Mboyi, Ilunga Kamika, Maggy Momba

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The aim of this study was to ascertain the survival limit and capability of commonly found wastewater protozoan (Aspidisca sp, Trachelophyllum sp, and Peranema sp) and bacterial (Bacillus licheniformis, Brevibacillus laterosporus, and Pseudomonas putida) species to remove COD while exposed to commercial nanomaterials under varying pH conditions. The experimental study was carried out in modified mixed liquor media adjusted to various pH levels (pH 2, 7 and 10), and a comparative study was performed to determine the difference between the cytotoxicity effects of commercial zinc oxide (nZnO) and silver (nAg) nanomaterials (NMs) on the target wastewater microbial communities using standard methods. The selected microbial communities were exposed to lethal concentrations ranging from 0.015 g/L to 40 g/L for nZnO and from 0.015 g/L to 2 g/L for nAg for a period of 5 days of incubation at 30°C (100 r/min). Compared with the absence of NMs in wastewater mixed liquor, the relevant environmental concentration ranging between 10 µg/L and 100 µg/L, for both nZnO and nAg caused no adverse effects, but the presence of 20 g of nZnO/L and 0.65 g of nAg/L significantly inhibited microbial growth. Statistical evidence showed that nAg was significantly more toxic compared to nZnO, but there was an insignificant difference in toxicity between microbial communities and pH variations. A significant decrease in the removal of COD by microbial populations was observed in the presence of NMs with a moderate correlation of r = 0.3 to r = 0.7 at all pH levels. It was evident that there was a physical interaction between commercial NMs and target wastewater microbial communities; although not quantitatively assessed, cell morphology and cell death were observed. Such phenomena suggest the high resilience of the microbial community, but it is the accumulation of NMs that will have adverse effects on the performance in terms of COD removal.

Keywords: bacteria, biological treatment, chemical oxygen demand (COD) and nanomaterials, consortium, pH, protozoan

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Authors: Hui Liu, Xiaozan Wang, Jiarong Zhong, Ziming Shao

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Introduction: Related research shows that students don’t concentrate on teacher’s speaking in the classroom. The d2 attention test is a time-limited test about selective attention. The d2 attention test can be used to evaluate individual selective attention. Purpose: To use the d2 attention test tool to measure the difference between the attention level of the experimental class and the control class before and after Brain-Break and to explore the effect of Brain-Break in the classroom on students' selective attention. Methods: According to the principle of no difference in pre-test data, two classes in the fourth- grade of Shenzhen Longhua Central Primary School were selected. After 20 minutes of class in the third class in the morning and the third class in the afternoon, about 3-minute Brain-Break intervention was performed in the experimental class for 10 weeks. The normal class in the control class did not intervene. Before and after the experiment, the d2 attention test tool was used to test the attention level of the two-class students. The paired sample t-test and independent sample t-test in SPSS 23.0 was used to test the change in the attention level of the two-class classes around 10 weeks. This article only presents results with significant differences. Results: The independent sample t-test results showed that after ten-week of Brain-Break, the missed errors (E1 t = -2.165 p = 0.042), concentration performance (CP t = 1.866 p = 0.05), and the degree of omissions (Epercent t = -2.375 p = 0.029) in experimental class showed significant differences compared with control class. The students’ error level decreased and the concentration increased. Conclusions: Adding Brain-Break interventions in the classroom can effectively improve the attention level of fourth-grade primary school students to a certain extent, especially can improve the concentration of attention and decrease the error rate in the tasks. The new sport's learning model is worth promoting

Keywords: cultural class, micromotor, attention, D2 test

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Authors: Kyohei Yoshino, Masahiko Matsumiya, Yuji Sasaki

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Recently, studies have been conducted on Au(III) extraction using ionic liquids (ILs) as extractants or diluents. ILs such as piperidinium, pyrrolidinium, and pyridinium have been studied as extractants for noble metal extractions. Furthermore, the polarity, hydrophobicity, and solvent miscibility of these ILs can be adjusted depending on their intended use. Therefore, the unique properties of ILs make them functional extraction media. The extraction mechanism of Au(III) using phosphonium-based ILs and relevant thermodynamic studies are yet to be reported. In the present work, we focused on the mechanism of Au(III) extraction and related thermodynamic analyses using phosphonium-based ILs. Triethyl-n-pentyl, triethyl-n-octyl, and triethyl-n-dodecyl phosphonium bis(trifluoromethyl-sulfonyl)amide, [P₂₂₂ₓ][NTf₂], (X = 5, 8, and 12) were investigated for Au(III) extraction. The IL–Au complex was identified as [P₂₂₂₅][AuCl₄] using UV–Vis–NIR and Raman spectroscopic analyses. The extraction behavior of Au(III) was investigated with a change in the [P₂₂₂ₓ][NTf₂]IL concentration from 1.0 × 10–4 to 1.0 × 10–1 mol dm−3. The results indicate that Au(III) can be easily extracted by the anion-exchange reaction in the [P₂₂₂ₓ][NTf₂]IL. The slope range 0.96–1.01 on the plot of log D vs log[P₂₂₂ₓ][NTf2]IL indicates the association of one mole of IL with one mole of [AuCl4−] during extraction. Consequently, [P₂₂₂ₓ][NTf₂] is an anion-exchange extractant for the extraction of Au(III) in the form of anions from chloride media. Thus, this type of phosphonium-based IL proceeds via an anion exchange reaction with Au(III). In order to evaluate the thermodynamic parameters on the Au(III) extraction, the equilibrium constant (logKₑₓ’) was determined from the temperature dependence. The plot of the natural logarithm of Kₑₓ’ vs the inverse of the absolute temperature (T–1) yields a slope proportional to the enthalpy (ΔH). By plotting T–1 vs lnKₑₓ’, a line with a slope range 1.129–1.421 was obtained. Thus, the result indicated that the extraction reaction of Au(III) using the [P₂₂₂ₓ][NTf₂]IL (X=5, 8, and 12) was exothermic (ΔH=-9.39〜-11.81 kJ mol-1). The negative value of TΔS (-4.20〜-5.27 kJ mol-1) indicates that microscopic randomness is preferred in the [P₂₂₂₅][NTf₂]IL extraction system over [P₂₂₂₁₂][NTf₂]IL. The total negative alternation in Gibbs energy (-5.19〜-6.55 kJ mol-1) for the extraction reaction would thus be relatively influenced by the TΔS value on the number of carbon atoms in the alkyl side length, even if the efficiency of ΔH is significantly influenced by the total negative alternations in Gibbs energy. Electrochemical analysis revealed that extracted Au(III) can be reduced in two steps: (i) Au(III)/Au(I) and (ii) Au(I)/Au(0). The diffusion coefficients of the extracted Au(III) species in [P₂₂₂ₓ][NTf₂] (X = 5, 8, and 12) were evaluated from 323 to 373 K using semi-integral and semi-differential analyses. Because of the viscosity of the IL medium, the diffusion coefficient of the extracted Au(III) increases with increasing alkyl chain length. The 4f7/2 spectrum based on X-ray photoelectron spectroscopy revealed that the Au electrodeposits obtained after 10 cycles of continuous extraction and electrodeposition were in the metallic state.

Keywords: au(III), electrodeposition, phosphonium-based ionic liquids, solvent extraction

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Authors: Anna Wolowicz, Katarzyna Staszak, Zbigniew Hubicki

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Nowadays heavy metal ions as well as surfactants are widely used throughout the world due to their useful properties. The consequence of such widespread use is their significant production. On the other hand, the increasing demand for surfactants and heavy metal ions results in production of large amounts of wastewaters which are discharged to the environment from mining, metal plating, pharmaceutical, cosmetic, fertilizer, paper, pesticide and electronic industries, pigments producing, petroleum refining and from autocatalyst, fibers, food, polymer industries etc. Heavy metal ions are non-biodegradable in the environment, cable of accumulation in living organisms and organs, toxic and carcinogenic. On the other hand, not only heavy metal ions but also surfactants affect the purity of water and soils. Some of surfactants are also toxic, harmful and dangerous because they are able to penetrate into surface waters causing foaming, blocked diffusion of oxygen from the atmosphere and act as emulsifiers of hydrophobic substances and increase solubility of many the dangerous pollutants. Among surfactants the anionic ones dominate and their share in the global production of surfactants is around 50 ÷ 60%. Due to the negative impact of heavy metals and surfactants on aquatic ecosystems and living organisms, removal and monitoring of their concentration in the environment is extremely important. Surfactants and heavy metal ions removal can be achieved by different biological and physicochemical methods. The adsorption as well as the ion-exchange methods play here a significant role. The aim of this study was heavy metal ions removal from aqueous solutions using different types of ion exchangers in the presence of anionic surfactants. Preliminary studies of copper(II), nickel(II), zinc(II) and cobalt(II) removal from acidic solutions using ion exchangers (Lewatit MonoPlus TP 220, Lewatit MonoPlus SR 7, Purolite A 400 TL, Purolite A 830, Purolite S 984, Dowex PSR 2, Dowex PSR3, Lewatit AF-5) allowed to select the most effective ones for the above mentioned sorbates and then to checking their removal efficiency in the presence of anionic surfactants. As it was found out Lewatit MonoPlus TP 220 of the chelating type, show the highest sorption capacities for copper(II) ions in comparison with the other ion exchangers under discussion, e.g. 9.98 mg/g (0.1 M HCl); 9.12 mg/g (6 M HCl). Moreover, cobalt(II) removal efficiency was the highest in 0.1 M HCl using also Lewatit MonoPlus TP 220 (6.9 mg/g) similar to zinc(II) (9.1 mg/g) and nickiel(II) (6.2 mg/g). As the anionic surfactant sodium dodecyl sulphate (SDS) was used and surfactant parameters such as viscosity (η), density (ρ) and critical micelle concentration (CMC) were obtained: η = 1.13 ± 0,01 mPa·s; ρ = 999.76 mg/cm3; CMC = 2.26 g/cm3. The studies of copper(II) removal from acidic solutions in the presence of SDS of different concentration show negligible effects on copper(II) removal efficiency. The sorption capacity of Cu(II) from 0.1 M acidic solution of 500 mg/L initial concentration was equal to 46.8 mg/g whereas in the presence of SDS 45.3 mg/g (0.1 mg SDS/L), 47.1 mg/g (0.5 mg SDS/L), 46.6 mg/g (1 mg SDS/L).

Keywords: anionic surfactant, heavy metal ions, ion exchanger, removal

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Authors: Juan Manuel Brito-Diaz

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The emergence of urban environmentalism in Spain is related to the processes of economic transformation and growing urbanization that occurred during the end of the Franco regime and the democratic transition. This paper analyzes the urban environmental mobilizations and their impacts as relevant democratizing agents in the processes of political change in cities. It’s an under-researched topic and studies on environmental movements in Spain have paid little attention to it. This research takes as its starting point the close link between democratization and environmentalism, since it considers that environmental conflicts are largely a consequence of democratic problems, and that the impacts of environmental movements are directly linked to the democratization. The study argues that the environmental movements that emerged in Spain at the end of the dictatorship and the democratic transition are an important part of the broad and complex associative fabric that promoted the democratization process. The research focuses on investigating the environmental protest in Las Palmas de Gran Canaria—the most important city in the Canary Islands—between 1970 and 1983, concurrently with the last local governments of the dictatorship and the first democratic city councils. As it is a case study, it opens up the possibility to ask multiple specific questions and assess each of the responses obtained. Although several research methodologies have been applied, such as the analysis of historical archives documentation or oral history interviews, mainly a very widespread methodology in the sociology of social movements, although very little used by social historians, has been used: the Protest Event Analysis (PEA). This methodology, which consists of generating a catalog of protest events by coding data around previously established variables, has allowed me to map, analyze and interpret the occurrence of protests over time and space, and associated factors, through content analysis. For data collection, news from local newspapers have provided a large enough sample to analyze the properties of social protest -frequency, size, demands, forms, organizers, etc.—and relate them to another type of information related to political structures and mobilization repertoires, encouraging the establishment of connections between the protest and the political impacts of urban movements. Finally, the study argues that the environmental movements of this period were essential to the construction of the new democratic city in Spain, not only because they established the issues of sustainability and urban environmental justice on the public agenda, but also because they proposed that conflicts derived from such matters should ultimately be resolved through public deliberation and citizen participation.

Keywords: democratization, environmental movements, political impacts, social movements

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Authors: Alireza Hashemi

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In recent decades, language teaching methodology has undergone significant changes due to the advent of computers and the growth of educational software. French language education has also benefited from these developments, and various software has been produced to facilitate the learning of this language. However, the question arises whether these software programs meet the educational needs of Iranian learners, particularly in Semnan Province. The aim of this study is to evaluate the efficiency and effectiveness of French language educational software for learners in Semnan Province, considering educational, cultural, and technical criteria. In this study, content analysis and performance evaluation methods were used to examine the educational software ‘Français Facile’. This software was evaluated based on criteria such as teaching methods, cultural compatibility, and technical features. To collect data, standardized questionnaires and semi-structured interviews with learners in Semnan Province were used. Additionally, the SPSS statistical software was employed for quantitative data analysis, and the thematic analysis method was used for qualitative data. The results indicated that the ‘Français Facile’ software has strengths such as providing diverse educational content and an interactive learning environment. However, some weaknesses include the lack of alignment of educational content with the learning culture of learners in Semnan Province and technical issues in software execution. Statistical data showed that 65% of learners were satisfied with the educational content, but 55% reported issues related to cultural alignment with their needs. This study indicates that to enhance the efficiency of French language educational software, there is a need to localize educational content and improve technical infrastructure. Producing locally adapted educational software can improve the quality of language learning and increase the motivation of learners in Semnan Province. This research emphasizes the importance of understanding the cultural and educational needs of learners in the development of educational software and recommends that developers of educational software pay special attention to these aspects.

Keywords: educational software, French language, Iran, learners in Semnan province

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Authors: Jasna Prester, Ivana Rašić Bakarić, Božidar Matijević

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Various prominent scholars and substantial practitioner-oriented literature on innovation orientation have shown positive effects on firm performance. There is a myriad of factors that influence and enhance innovation but it has been found in the literature that new product innovations accounted for an average of 14 percent of sales revenues for all firms. If there is one thing that has changed in innovation management during the last decade, it is the growing reliance on external partners. As a consequence, a new task for purchasing arises, as firms need to understand which suppliers actually do have high potential contributing to the innovativeness of the firm and which do not. Purchasing function in an organization is extremely important as it deals on an average of 50% or more of a firm's expenditures. In the nineties the purchasing department was largely seen as a transaction-oriented, clerical function but today purchasing integration provides a formal interface mechanism between purchasing and other firm functions that services other functions within the company. Purchasing function has to be organized differently to enable firm innovation potential. However, innovations are inherently risky. There are behavioral risk (that some partner will take advantage of the other party), technological risk in terms of complexity of products and processes of manufacturing and incoming materials and finally market risks, which in fact judge the value of the innovation. These risks are investigated in this work since it has been found in the literature that the higher the technological risk, higher will be the centralization of the purchasing function as an interface with other supply chain members. Most researches on organization of purchasing function were done by case study analysis of innovative firms. This work actually tends to prove or discard results found in the literature based on case study method. A large data set of 1493 companies, from 25 countries collected in the GMRG 4 survey served as a basis for analysis.

Keywords: purchasing function organization, innovation, technological risk, GMRG 4 survey

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Authors: Ekaterina G. Lipatova

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The developing potential of a video task in teaching foreign languages involves the opportunities to improve four aspects of speech production process: listening, reading, speaking and writing. A video represents the sequence of actions, realized in the pictures logically connected and verbalized speech flow that simplifies and stimulates the process of perception. In this connection listening skills of students are developed effectively as well as their intellectual properties such as synthesizing, analyzing and generalizing the information. In terms of teaching capacity, a video task, in our opinion, is more stimulating than a traditional listening, since it involves the student into the plot of the communicative situation, emotional background and potentially makes them react to the gist in the cognitive and communicative ways. To be an effective method of teaching the video task should be structured in the way of psycho-linguistic characteristics of speech production process, in other words, should include three phases: before-watching, while-watching and after-watching. The system of tasks provided to each phase might involve the situations on reflecting to the video content in the forms of filling-the-gap tasks, multiple choice, True-or-False tasks (reading skills), exercises on expressing the opinion, project fulfilling (writing and speaking skills). In the before-watching phase we offer the students to adjust their perception mechanism to the topic and the problem of the chosen video by such task as “what do you know about such a problem?”, “is it new for you?”, “have you ever faced the situation of…?”. Then we proceed with the lexical and grammatical analysis of language units that form the body of a speech sample to lessen the perception and develop the student’s lexicon. The goal of while-watching phase is to build the student’s awareness about the problem presented in the video and challenge their inner attitude towards what they have seen by identifying the mistakes in the statements about the video content or making the summary, justifying their understanding. Finally, we move on to development of their speech skills within the communicative situation they observed and learnt by stimulating them to search the similar ideas in their backgrounds and represent them orally or in the written form or express their own opinion on the problem. It is compulsory to highlight, that a video task should contain the urgent, valid and interesting event related to the future profession of the student, since it will help to activate cognitive, emotional, verbal and ethic capacity of students. Also, logically structured video tasks are easily integrated into the system of e-learning and can provide the opportunity for the students to work with the foreign language on their own.

Keywords: communicative situation, perception mechanism, speech production process, speech skills

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Authors: Rajai Al-Rousan

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The repair and strengthening of concrete structures is a big challenge for the concrete industry for both engineers and contractors. Due to increasing economical constraints, the current trend is to repair/upgrade deteriorated and functionally obsolete structures rather than replacing them with new structures. CFRP has been used previously by air space industries regardless of the high costs. The decrease in the costs of the composite materials, as results of the technology improvement, has made CFRP an alternative to conventional materials for many applications. The primary objective of this research is to investigate the flexural behavior of reinforced concrete (RC) beams externally strengthened with CFRP composites exposed for three years for the following conditions: (a) room temperature, (b) cyclic ponding in 15% salt-water solution, (c) hot-water of 65oC, and (d) rapid freeze/thaw cycles. Results indicated that the after three years of various environmental conditions, the bond strength between the concrete beams and CFRP sheets was not affected. No signs of separation or debonding of CFRP sheets were observed before testing. Also, externally strengthening RC beams with CFRP sheets leads to a substantial increase in the ductility of concrete structures. This is a result of forcing the concrete to undergo inelastic deformation, resulting in compression failure of the structure after yielding of steel reinforcement. In addition, exposure to heat water tank for three years reduces the ultimate load by about 11%. This 11% reduction in the ultimate load equates to about 53%, 46% and 68% loss of the gain of the strength attributed to the CFRP of 2/3 Layer, 1 Layers and 2 Layers CFRP Sheets respectively. This mean that with decreasing of number of layers the environmental exposure had an efficient effect on concrete by protection concrete from environmental effect and adverse effect on the bond performance.

Keywords: flexural, behavior, CFRP, composites, environment, conditions

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Authors: Nurcan Cetinkaya

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The aim of the study was to estimate the microbial-N flow to small intestine based on daily urinary purine derivatives(PD) mainly xanthine, hypoxanthine, uric acid and allantoin excretion in Angora goats fed by grass hay and concentrate (Period I); barley straw and concentrate (Period II). Daily urine samples were collected during last 3 days of each period from 10 individually penned Angora bucks( LW 30-35 Kg, 2-3 years old) receiving ad libitum grass hay or barley straw and 300 g/d concentrate. Fresh water was always available. 4N H2SO4 was added to collected daily urine .samples to keep pH under 3 to avoid of uric acid precipitation. Diluted urine samples were stored at -20°C until analysis. Urine samples were analyzed for xanthine, hypoxanthine, uric acid, allantoin and creatinine by High-Performance Liquid Chromatographic Method (HPLC). Urine was diluted 1:15 in ratio with water and duplicate samples were prepared for HPLC analysis. Calculated mean levels (n=60) for urinary xanthine, hypoxanthine, uric acid, allantoin, total PD and creatinine excretion were 0.39±0.02 , 0.26±0.03, 0.59±0.06, 5.91±0.50, 7.15±0.57 and 3.75±0.40 mmol/L for Period I respectively; 0.35±0.03, 0.21±0.02, 0.55±0.05, 5.60±0.47, 6.71±0.46 and 3.73±0.41 mmol/L for Period II respectively.Mean values of Period I and II were significantly different (P< 0.05) except creatinine excretion. Estimated mean microbial-N supply to the small intestine for Period I and II in Angora goats were 5.72±0.46 and 5.41±0.61 g N/d respectively. The effects of grass hay and barley straw feeding on microbial-N supply to small intestine were found significantly different (P< 0.05). In conclusion, grass hay showed a better effect on the ruminal microbial protein synthesis compared to barley straw, therefore; grass hay is suggested as roughage source in Angora goat feeding.

Keywords: angora goat, HPLC method, microbial-N supply to small intestine, urinary purine derivatives

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Authors: B. Baba Ahmed, P. Yanogo, B. Djibryl. N. Medas

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Introduction: Polio is a highly contagious viral infection, with children under 5 years of age being the most affected. It is a public health emergency of international concern. Polio surveillance in Mauritania has been ongoing since 1998 and has achieved "polio free" status in 2007. our objective is to analyse a pidemiological surveillance database of poliomyélitis in Mauritania from 2012-2019. Method: A transversal descriptive analysis of poliomyélitis database was carried out in Mauritania from 2012-2019.An exhaustive sampling was done on all suspected polio cases recorded in the database from 2012 -2019. This study used EPI-INFO 7.4 for frequency calculation for qualitative variables, mean and standard deviation for quantitative variables. Results: We found 459 suspected cases of polio over the study period with an average rate of acute non-polio flaccid paralysis of 25.4 cases/100,000 children under 15 years of age. The age group 0-6 years represented 75.2%. Males constituted 50.2%. Females represented 49.78% with a ratio of M/F=1.Among the 422 observations, the average age is 4 years +/- 3.38. The four regions, TIRIS-ZEMMOUR, INCHIRI, TAGANT, NOUACHCHOTT OUEST recorded the lowest percentages of notifications, respectively (3.28%; 3.93%; 4.37%; 4.8%). 99.34% [98.09-99.78] of cases presented acute flaccid paralysis. And 56.77% [52.19-61.23], had limb asymmetry. We showed that 82.93% [79.21-86.10], had fever. we found that 89.5% of suspected polio cases were investigated before 48 hours. And 88.39% of suspected cases had two adequate samples taken 48 hours apart and within 14 days after the onset of symptoms. Only 30.95% of samples arrived at the referral laboratory before 72 hours. Conclusion: This study has shown that Mauritania has achieved the objectives in most of the quantitative performance indicators of polio surveillance. This study has shown a low notification of cases in the northern and central regions of the country. There is a problem with the transport of samples to the laboratory.

Keywords: analysis, data base, Epi-Info, polio

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Authors: Ismaila Oladunni Muhammed, Adegbenga Raphael Ashiru

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Construction industry has been attributed to be the engine growth of Nigerian economic and infrastructural development. It promotes infrastructural development and grows an average output of Nigerian Gross Domestic Profit. However, from this great prospect, yearly reports show that consistent accidents on construction sites in Zamfara State has affected a substantial number of workers as they become temporarily or permanently disabled, thereby making many construction sites a death trap. This posed a great threat to the industry’s sustainability, de- motivate workers from working in the industry, and further have negative impact on the economy as well. It is as a result of high construction site accident currently experiencing in Zamfara state that this research was carried out to appraise the sustainability of health and safety of construction workers on sites. The proper practice and compliance to Construction Health and safety laws are very vital to the output and growth of Zamfara State construction sector. However, a quantitative approach was adopted to justify the aforesaid statement which will provide a broader understanding of the study. Descriptive statistical analysis was obtained through Statistical Package for the Social Sciences (SPSS Version 20). Furthermore, the findings from the research highlighted that the performance and output of construction workers on construction sites depends on the proper practice of health and safety. The research findings also recommended ways to enhance employers and employee’s compliance with existing laws guiding health and safety on Zamfara State construction sites. Nevertheless, the purpose of the paper is to appraise the sustainability of Health and Safety on Zamfara State construction sites. This study further provided thorough information for resolving challenges of construction sites accidents to improve construction firm productivity and also ensured construction worker’s safety on site.

Keywords: construction industry, health and safety regulations, causes of accident, construction safety practices

Procedia PDF Downloads 203

Authors: Marawan Abd Elbaset Mohamed, Hanan A. Ogaly, Rehab F. Abdel-Rahman, Ahmed-Farid O.A., Marwa S. Khattab, Reham M. Abd-Elsalam

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Liver fibrosis is a severe worldwide health concern due to various chronic liver disorders. Hepatic encephalopathy (HE) is one of its most common complications affecting liver and brain cognitive function. Beta-Carotene (B-Car) is an organic, strongly colored red-orange pigment abundant in fungi, plants, and fruits. The study attempted to know B-Car neuroprotective potential against thioacetamide (TAA)-induced neurotoxicity and cognitive decline in HE in rats. Hepatic encephalopathy was induced by TAA (100 mg/kg, i.p.) three times per week for two weeks. B-Car was given orally (10 or 20 mg/kg) daily for two weeks after TAA injections. Organ body weight ratio, Serum transaminase activities, liver’s antioxidant parameters, ammonia, and liver histopathology were assessed. Also, the brain’s mitogen-activated protein kinase (MAPK), nuclear factor kappa B (NF-κB), antioxidant parameters, adenosine triphosphate (ATP), adenosine monophosphate (AMP), norepinephrine (NE), dopamine (DA), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) cAMP response element-binding protein (CREB) expression and B-cell lymphoma 2 (Bcl-2) expression were measured. The brain’s cognitive functions (Spontaneous locomotor activity, Rotarod performance test, Object recognition test) were assessed. B-Car prevented alteration of the brain’s cognitive function in a dose-dependent manner. The histopathological outcomes supported these biochemical evidences. Based on these results, it could be established that B-Car could be assigned to treat the brain’s neurotoxicity consequences of HE via downregualtion of MAPK/NF-κB signaling pathways.

Keywords: beta-carotene, liver injury, MAPK, NF-κB, rat, thioacetamide

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Authors: Zafar Iqbal, Nigel P. Grigg, K. Govindaraju, Nicola M. Campbell-Allen

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Quality Function Deployment (QFD) is structured approach. It has been used to improve the quality of products and process in a wide range of fields. Using this systematic tool, practitioners normally rank Voice of Customer ratings (VoCs) in order to produce Improvement Ratios (IRs) which become the basis for prioritising process / product design or improvement activities. In one matrix of the House of Quality (HOQ) competitors are rated. The method of obtaining improvement ratios (IRs) does not always integrate the competitors’ rating in a systematic way that fully utilises competitor rating information. This can have the effect of diverting QFD practitioners’ attention from a potentially important VOC to less important VOC. In order to enhance QFD analysis, we present a more systematic method for integrating competitor ratings, utilising the geometric mean of the customer rating matrix. In this paper we develop a new approach, based on the Analytic Hierarchy Process (AHP), in which we generating a matrix of multiple comparisons of all competitors, and derive a geometric mean for each competitor. For each VOC an improved IR is derived which-we argue herein - enhances the initial VOC importance ratings by integrating more information about competitor performance. In this way, our method can help overcome one of the possible shortcomings of QFD. We then use a published QFD example from literature as a case study to demonstrate the use of the new AHP-based IRs, and show how these can be used to re-rank existing VOCs to -arguably- better achieve the goal of customer satisfaction in relation VOC ratings and competitors’ rankings. We demonstrate how two dimensional AHP-based geometric mean derived from the multiple competitor comparisons matrix can be useful for analysing competitors’ rankings. Our method utilises an established methodology (AHP) applied within an established application (QFD), but in an original way (through the competitor analysis matrix), to achieve a novel improvement.

Keywords: quality function deployment, geometric mean, improvement ratio, AHP, competitors ratings

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Authors: Farshad Ghodoosi

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This article analyzes the effect of supervening events in contracts. Contracts serve an important function: allocation of risks. In spite of its importance, the case law and the doctrine are messy and inconsistent. This article provides a fresh look at excuse doctrines (i.e., force majeure, impracticability, impossibility, and frustration) with a focus on force majeure clauses. The article makes the following contributions: First, it furnishes a new conceptual and theoretical framework of excuse doctrines. By distilling the decisions, it shows that excuse doctrines rests on the triangle of control, foreseeability, and contract language. Second, it analyzes force majeure clauses used by S&P 500 companies to understand the stickiness and similarity of such clauses and the events they cover. Third, using computational and statistical tools, it analyzes US cases since 1810 in order to assess the weight given to the triangle of control, foreseeability, and contract language. It shows that the control factor plays an important role in force majeure analysis, while the contractual interpretation is the least important factor. The Article concludes that it is the standard for control -whether the supervening event is beyond the control of the party- that determines the outcome of cases in the force majeure context and not necessarily the contractual language. This article has important implications on COVID-19-related contractual cases. Unlike the prevailing narrative that it is the language of the force majeure clause that’s determinative, this article shows that the primarily focus of the inquiry will be on whether the effects of COVID-19 have been beyond the control of the promisee. Normatively, the Article suggests that the trifactor of control, foreseeability, and contractual language are not effective for allocation of legal risks in times of crises. It puts forward a novel approach to force majeure clauses whereby that the courts should instead focus on the degree to which parties have relied on (expected) performance, in particular during the time of crisis.

Keywords: contractual risks, force majeure clauses, foreseeability, control, contractual language, computational analysis

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Authors: Sylvia Huang

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Contemporary Buddhist music has been emerged at the new forms of large-scale public Buddhist ritual ceremonies that may involve up to 10,000 participants at a time. Since 2007, the Buddha’s Birthday ceremony (Sanskrit, Vesak) by the Buddhist Tzu Chi Foundation has being held at major cities in Taiwan and many affiliated Tzu Chi offices around the world. Analysis of this modern and technologically-dependent ceremony sheds new light on the significance of music in contemporary Buddhist ritual, and also on recently enhanced and increasingly intimate connections between music and Buddhism. Through extensive ethnographic research of ten years (2007-2017), the research explores how the form of contemporary Buddhist music relates to the role of music in participants’ experience of the ritual and the way in which they construct meaning. The theoretical approach draws on both ethnomusicology and Buddhist teachings, Dharma. As soundscape is defined as the entire sonic energy produced by a landscape, the concept of soundscape is utilised to examine the contemporary ritual music in the Tzu Chi Vesak ceremony. The analysis opens new territory in exploring how analysis of Buddhist music can benefit from incorporating Buddhist philosophy within the methodological approach. Main findings are: 1) music becomes a method for Buddhist understanding through a focus in particular on how the ceremonial program is followed by music, and 2) participants engage with each other and entrain with music in the Vesak ceremony. As Buddhist sounding, such as scripture reading, liturgical chanting, and ceremonial music singing, is a sonic epistemological knowing of the conditions in which Buddhism is practiced, experienced, and transmigrated, the research concludes by showing that studies of Buddhist music have the potential to reveal distinctively Buddhist concepts, meaning, and values. Certain principles of Buddhist philosophy are adopted within ethnomusicological analysis to further enhance understandings of the crucial function of music within such a ritual context. Finally, the contemporary Buddhist music performance in the ceremony is possessed as a means of direct access to the spiritual experience in Buddhism.

Keywords: buddhist music, Taiwan, soundscape, Vesak ceremony

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Authors: Som Pal Baliyan

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The purpose of this quantitative study was to analyze farm management skills in broiler poultryproducers in Botswana. The study adopted a descriptive and correlation research design. The population of the study was the poultry farm operators who had been in broiler poultry farming at least for two years. Based on the information from literature, a questionnaire was constructed for data collection on seven areas of farm management skills namely; planning skills, accounting and financial management skills, production management skills, product procurement and marketing skills, decision making skills, risk management skills, and specific technical skills. The validity and reliability of the questionnaire were accomplished by a panel of experts and by calculating the Cronbach’s alpha coefficient, respectively. Data were collected through a survey of 60 randomly sampled poultry farm operators in Botswana. Data were analyzed through descriptive statistical tools whereby the level of farm management skills were determined by calculating means and standard deviations of the management skills among the broiler producers. The level of farm management skills in broilers producers was discussed. All the seven farm management skills were ranked based on their calculated means. The specific technical skills and risk management skills were the highest and the lowest ranked farm management skills, respectively.Findings revealed that the broiler producers had skills above the average level only in specific technical skills whereas the skill levels in the remaining six farm management skills under study were found below the average level. This prevailing low level of farm management skills can be justified asthe cause of failure or poor performance of the broiler poultry farms in Botswana. Therefore, in order to improve the efficiency and productivityin broiler production in the country, it was recommended that the broiler poultry producers should be adequately trained in areas of planning skills, financial management skills, production management skills, product procurement and marketing skills, decision making skills and risk management skills.

Keywords: poultry production, broiler production, management skills, levels of skills

Procedia PDF Downloads 391

Authors: Marcelo T. Okano, Oduvaldo Vendrametto, Osmildo S. Santos, Marcelo E. Fernandes, Heide Landi

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The literature on the interorganizational relationship between companies and organizations has increased in recent years, but there are still doubts about the various settings. The interorganizational networks are important in economic life, the fact facilitate the complex interdependence between transactional and cooperative organizations. A need identified in the literature is the lack of indicators to measure and identify the types of existing networks. The objective of this research is to examine the interorganizational relationships of two milk chains through indicators proposed by the theories of the four authors, characterizing them as network or not and what the benefits obtained by the chain organization. To achieve the objective of this work was carried out a survey of milk producers in two regions of the state of São Paulo. To collect the information needed for the analysis, exploratory research, qualitative nature was used. The research instrument of this work consists of a roadmap of semistructured interviews with open questions. Some of the answers were directed by the interviewer in the form of performance notes aimed at detecting the degree of importance, according to the perception of intensity to that regard. The results showed that interorganizational relationships are small and largely limited to the sale of milk or dairy cooperatives. These relationships relate only to trade relations between the owner and purchaser of milk. But when the producers are organized in associations or networks, interorganizational relationships and increase benefits for all participants in the network. The various visits and interviews in several dairy farms in the regions of São Pau-lo (indicated that the inter-relationships are small and largely limited to the sale of milk to cooperatives or dairy. These relationships refer only to trade relations between the owner and the purchaser of milk. But when the producers are organized in associations or networks, interorganizational relationships increase and bring benefits to all participants in the network.

Keywords: interorganizational networks, dairy chain, interorganizational system, São Pau-lo

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Authors: Hanen Bouaziz, Moez Rafrafi, Ghada Ben Salah, Kamel Jamoussi, Tahia Boudawara, Najiba Zeghal

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The present study investigated the protective role of Hyparrhenia hirta against sodium nitrate (NaNO3)-induced nephrotoxicity. A high-performance liquid chromatography coupled with a mass spectrometer (HPLC-MS) method was developed to separate and identify flavonoids in Hyparrhenia hirta. Seven flavonoids were identified as 3-O-methylquercetin, luteolin-7-O-glucoside, luteolin, apigenin-7-O-glucoside, apigenin-8-C-glucoside, luteolin-8-C-glucoside and luteolin-6-C-glucoside. Wistar rats were randomly divided into three groups: a control group and two treated groups during 50 days with NaNO3 administered either alone in drinking water or co-administered with Hyparrhenia hirta. NaNO3 treatment induced a significant increase in plasma levels of creatinine, urea and uric while urinary level decreased significantly. Nephrotoxicity induced by NaNO3 was characterized by significant increase in creatinine clearance. In parallel, a significant increase in malondialdehyde level along with a concomitant decrease in total glutathione content and superoxide dismutase, catalase and glutathione peroxidase activities were observed in the kidney after NaNO3 treatment. The histopathological changes in kidney after NaNO3 administration were shrunken. There were renal tubule cell degeneration and infiltration of mononuclear cells. Most glomeruli revealed shrinkage, a wide capsular space and a peri-glomerular mononuclear cells infiltration. Hyparrhenia hirta supplementation showed a remarkable amelioration of the abnormalities cited above. The results concluded that the treatment with Hyparrhenia hirta had a significant role in protecting the animals from nitrate-induced kidney dysfunction.

Keywords: flavonoids, hyparrhenia hirta, kidney, nitrate toxicity, oxidative stress, rat

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Authors: Mohammad Rahim Rahimi, Yuji Hoshino

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Building Information Management (BIM) at recent years has widespread consideration on the Architecture, Engineering and Construction (AEC). BIM has been bringing innovation in AEC industry and has the ability to improve the construction industry with high quality, reduction time and budget of project. Meanwhile, BIM support model and process in AEC industry, the process include the project time cycle, estimating, delivery and generally the way of management of project but not limited to those. This research carried the BIM advantages, adaptation and challenges of implementation in Kabul region. Capital Region Independence Development Authority (CRIDA) have responsibilities to implement the development projects in Kabul region. The method of study were considers on advantages and reasons of BIM performance in Afghanistan based on online survey and data. Besides that, five projects were studied, the reason of consideration were many times design revises and changes. Although, most of the projects had problems regard to designing and implementation stage, hence in canal project was discussed in detail with the main reason of problems. Which were many time changes and revises due to the lack of information, planning, and management. In addition, two projects based on BIM utilization in Japan were also discussed. The Shinsuizenji Station and Oita River dam projects. Those are implemented and implementing consequently according to the BIM requirements. The investigation focused on BIM usage, project implementation process. Eventually, the projects were the comparison with CRIDA and BIM utilization in Japan. The comparison will focus on the using of the model and the way of solving the problems based upon on the BIM. In conclusion, that BIM had the capacity to prevent many times design changes and revises. On behalf of achieving those objectives are required to focus on data management and sharing, BIM training and using new technology.

Keywords: construction information management, implementation and adaptation of BIM, project management, developing countries

Procedia PDF Downloads 115

Authors: M. Shaheed Hartley

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Science and mathematics are regarded as gateway subjects in South Africa as they are the perceived route to careers in science, engineering, technology and mathematics (STEM). One of the biggest challenges that the country faces is the poor achievement of learners in these two learning areas in the external high school exit examination. To compound the problem many national and international benchmark tests paint a bleak picture of the state of science and mathematics in the country. In an attempt to address this challenge, the education department of the Eastern Cape Province invited the Science Learning Centre of the University of the Western Cape to provide training to their science teachers in the form of a structured course conducted on a part-time basis in 2010 and 2011. The course was directed at improving teachers’ content knowledge, pedagogical strategies and practical and experimental skills. A total of 41 of the original 50 science teachers completed the course and received their certificates in 2012. As part of their continuous professional development, 31 science teachers enrolled for BEd Hons in science education in 2013 and 28 of them completed the course in 2014. These students graduated in 2015. Of the 28 BEd Hons students who completed the course 23 registered in 2015 for Masters in Science Education and were joined by an additional 3 students. This paper provides a reflection by science educators on the training, supervision and mentorship provided to them as students of science education. The growth and development of students through their own reflection and understanding as well as through the eyes of the lecturers and supervisors that took part in the training provide the evaluation of the professional development process over the past few years. This study attempts to identify the merits, challenges and limitations of this project and the lessons to be learnt on such projects. It also documents some of the useful performance indicators with a view to developing a framework for good practice for such programmes.

Keywords: reflection, science education, professional development, rural schools

Procedia PDF Downloads 182

Authors: Nkechinyere Joy Olawuyi, Babajide Samuel Afolabi, Bola Ibitoye

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This study collected a preprocessed dataset of chest radiographs and formulated a deep neural network model for detecting abnormalities. It also evaluated the performance of the formulated model and implemented a prototype of the formulated model. This was with the view to developing a deep neural network model to automatically classify abnormalities in chest radiographs. In order to achieve the overall purpose of this research, a large set of chest x-ray images were sourced for and collected from the CheXpert dataset, which is an online repository of annotated chest radiographs compiled by the Machine Learning Research Group, Stanford University. The chest radiographs were preprocessed into a format that can be fed into a deep neural network. The preprocessing techniques used were standardization and normalization. The classification problem was formulated as a multi-label binary classification model, which used convolutional neural network architecture to make a decision on whether an abnormality was present or not in the chest radiographs. The classification model was evaluated using specificity, sensitivity, and Area Under Curve (AUC) score as the parameter. A prototype of the classification model was implemented using Keras Open source deep learning framework in Python Programming Language. The AUC ROC curve of the model was able to classify Atelestasis, Support devices, Pleural effusion, Pneumonia, A normal CXR (no finding), Pneumothorax, and Consolidation. However, Lung opacity and Cardiomegaly had a probability of less than 0.5 and thus were classified as absent. Precision, recall, and F1 score values were 0.78; this implies that the number of False Positive and False Negative is the same, revealing some measure of label imbalance in the dataset. The study concluded that the developed model is sufficient to classify abnormalities present in chest radiographs into present or absent.

Keywords: transfer learning, convolutional neural network, radiograph, classification, multi-label

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Authors: Belayneh Yohannes

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In Ethiopia, onion production is increasing from time to time mainly due to its high profitability per unit area. Onion has a significant contribution to generating cash income for farmers in the Raya Azebo district. Therefore, enhancing onion producers’ access to the market and improving market linkage is an essential issue. Hence, this study aimed to analyze structure-conduct-performance of onion market and identifying factors affecting the market supply of onion producers. Data were collected from both primary and secondary sources. Primary data were collected from 150 farm households and 20 traders. Four onion marketing channels were identified in the study area. The highest total gross margin is 27.6 in channel IV. The highest gross marketing margin of producers of the onion market is 88% in channel II. The result from the analysis of market concentration indicated that the onion market is characterized by a strong oligopolistic market structure, with the buyers’ concentration ratio of 88.7 in Maichew town and 82.7 in Mekelle town. Lack of capital, licensing problems, and seasonal supply was identified as the major entry barrier to onion marketing. Market conduct shows that the price of onion is set by traders while producers are price takers. Multiple linear regression model results indicated that family size in adult equivalent, irrigated land size, access to information, frequency of extension contact, and ownership of transport significantly determined the quantity of onion supplied to the market. It is recommended that strengthening and diversifying extension services in information, marketing, post-harvest handling, irrigation application, and water harvest technology is highly important.

Keywords: oligopoly, onion, market chain, multiple linear regression

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Authors: Carol Anne Hargreaves

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A key issue in stock investment is how to select representative features for stock selection. The objective of this paper is to firstly determine whether an automated stock investment system, using machine learning techniques, may be used to identify a portfolio of growth stocks that are highly likely to provide returns better than the stock market index. The second objective is to identify the technical features that best characterize whether a stock’s price is likely to go up and to identify the most important factors and their contribution to predicting the likelihood of the stock price going up. Unsupervised machine learning techniques, such as cluster analysis, were applied to the stock data to identify a cluster of stocks that was likely to go up in price – portfolio 1. Next, the principal component analysis technique was used to select stocks that were rated high on component one and component two – portfolio 2. Thirdly, a supervised machine learning technique, the logistic regression method, was used to select stocks with a high probability of their price going up – portfolio 3. The predictive models were validated with metrics such as, sensitivity (recall), specificity and overall accuracy for all models. All accuracy measures were above 70%. All portfolios outperformed the market by more than eight times. The top three stocks were selected for each of the three stock portfolios and traded in the market for one month. After one month the return for each stock portfolio was computed and compared with the stock market index returns. The returns for all three stock portfolios was 23.87% for the principal component analysis stock portfolio, 11.65% for the logistic regression portfolio and 8.88% for the K-means cluster portfolio while the stock market performance was 0.38%. This study confirms that an automated stock investment system using machine learning techniques can identify top performing stock portfolios that outperform the stock market.

Keywords: machine learning, stock market trading, logistic regression, cluster analysis, factor analysis, decision trees, neural networks, automated stock investment system

Procedia PDF Downloads 143