Problems of drinking water treatment along Ismailia Canal Province, Egypt     

Geriesh MH  Balke KD  El-Rayes AE 《Journal of Zhejiang University. Science. B》2008,9(3):232-242

The present drinking water purification system in Egypt Uses surface water as a raw water supply without a pre-liminary filtration process.On the other hand,chlorine gas iS added as a disinfectant agent in two steps,pre- and post.chlorination.Due to these reasons most of water treatment plants suffer low fltering effectiveness and produce the trihalomethane (THM) species as a chlorination by-product.The Ismailia Canal represents the most distal downstream of the main Nile Rivet.ThUS its water contains all the proceeded pollutants discharged into the Nile.In addition.the downstream reaches of the canal act as an agricultural drain during the closing period of the High Dam gates in January and February every year.Moreover,the wide in-dustrial zone along the upstream course of the carlal enriches the canal water with high concentrations of heavy metals.The obtained results indicate that the canal gains up to 24.06×106m3 of water from the surrounding shallow aquifer during the closing period ofthe High Dam gates,while during the rest ofthe year,the callal acts as an influent stream losing about 99.6×106m3 of its water budget.The reduction oftotaI organic carbon(TOC) and suspended particulate mattes(SPMs)should be one of the central goals of any treatment plan to avoid the disinfectants by-products.The combination of sedimentation basins.gravel pre-filtration and slow sand filtration,and underground passage with microbiological oxidation-reduction and adsorption criteria showed good removal of parasites and bacteria and complete elimination of TOC.SPM and heavy metals.Moreover,it reduces the use of disinfectants chemicals and lowers the treatment costs.However,this purification system under the arid climate prevailing in Egypt should be tested and modified prior to application.  相似文献   

Improving the quality of contextualized questions: an experimental investigation of focus     

Ayesha Ahmed 《Assessment in Education: Principles, Policy & Practice》2007,14(2):201-232

Setting examination questions in real‐world contexts is widespread. However, when students are reading contextualized questions there is a risk that the cognitive processes provoked by the context can interfere with their understanding of the concepts in the question. Validity may then be compromised. We introduce the concept of focus: a question in a given context is focused to the extent that it addresses the aspects of the context that will be most salient in real life for the students being tested. A more focused context will then help activate relevant concepts, rather than interfering with comprehension and reasoning. In this study, the contexts of questions from a science test for 14‐year‐olds in England were manipulated to increase or decrease the amount of focus. In every instance more focused questions proved better than less focused ones. With additional evidence from interview protocols, we also consider the effects of context focus on the question answering process.  相似文献   

A comparative study of conventional and supercritical fluid extraction methods for the recovery of secondary metabolites from <Emphasis Type="Italic">Syzygium campanulatum</Emphasis> Korth     

Abdul Hakeem Memon  Mohammad Shahrul Ridzuan Hamil  Madeeha Laghari  Fahim Rithwan  Salman Zhari  Mohammed Ali Ahmed Saeed  Zhari Ismail  Amin Malik Shah Abdul Majid 《Journal of Zhejiang University. Science. B》2016,17(9):683-691

Syzygium campanulatum Korth is a plant, which is a rich source of secondary metabolites (especially flavanones, chalcone, and triterpenoids). In our present study, three conventional solvent extraction (CSE) techniques and supercritical fluid extraction (SFE) techniques were performed to achieve a maximum recovery of two flavanones, chalcone, and two triterpenoids from S. campanulatum leaves. Furthermore, a Box-Behnken design was constructed for the SFE technique using pressure, temperature, and particle size as independent variables, and yields of crude extract, individual and total secondary metabolites as the dependent variables. In the CSE procedure, twenty extracts were produced using ten different solvents and three techniques (maceration, soxhletion, and reflux). An enriched extract of five secondary metabolites was collected using n-hexane:methanol (1:1) soxhletion. Using food-grade ethanol as a modifier, the SFE methods produced a higher recovery (25.5%?84.9%) of selected secondary metabolites as compared to the CSE techniques (0.92%?66.00%).  相似文献   

Use of Felder and Silverman learning style model for online course design     

El-Bishouty  Moushir M.  Aldraiweesh  Ahmed  Alturki  Uthman  Tortorella  Richard  Yang  Junfeng  Chang  Ting-Wen  Graf  Sabine  Kinshuk 《Educational technology research and development : ETR & D》2019,67(1):161-177

Educational technology research and development - Learning Management Systems are used in millions of higher education courses, across various countries and disciplines. Teachers build courses...  相似文献   

Critical educational issues and non-formal education     

Manzoor Ahmed 《Prospects》1983,13(1):33-43

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Wadi Allaqi Biosphere Reserve     

Springuel  Irina  Belal  Ahmed Esmat 《Prospects》2003,33(3):325-337

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Attitudes of special education teachers towards using technology in inclusive classrooms: a mixed‐methods study          下载免费PDF全文

Ahmed Hassan Hemdan Mohamed 《Journal of Research in Special Educational Needs》2018,18(4):278-288

The purpose of this mixed‐methods study was to explore special education teachers’ attitudes towards using technology in inclusive classrooms in Oman. The sample consisted of 428 special education teachers working in Omani public schools (250 teachers of students with learning disabilities (LD), 90 teachers of students with intellectual disability and 88 teachers of students with hearing impairment). Participants responded to the attitudes towards computers questionnaire. For the qualitative section of this study, three semi‐structured group interviews were conducted with a group of special education teachers: 15 teachers of students with hearing impairment, 15 teachers of students with intellectual disabilities and 15 teachers of students with LD). Also, the teachers responded to a survey of educational technology which encompassed seven questions about computer technology. Results of the study indicated that the special education teachers’ attitudes towards using computers were generally positive. The most notable positive attitudes were in the following subscales: special education considerations, staff development considerations, computers use in society, and computers and quality of instruction issues. The analysis of variance results showed that experience and type of disability did not have a significant effect on teachers’ attitudes towards technology.  相似文献   

Confirmatory studies on the antioxidant and antidiabetic effect of quercetin in rats     

Mohamed Ahmed Abdelmoaty  M. A. Ibrahim  N. S. Ahmed  M. A. Abdelaziz 《Indian journal of clinical biochemistry : IJCB》2010,25(2):188-192

Quercetin (QE), one of natural flavanoid group, was widely distributed as a secondary metabolite in plant kingdom. It has been believed that oxidative stress plays a role in the pathogenesis of diabetes mellitus (DM). The aim of the present study was the evaluation of possible effects of QE on blood glucose and antioxidant enzymes in experimental streptozotocin (STZ)-induced diabetes in rats. STZ was injected intraperitoneally with single dose of 50 mg/kg for diabetes induction. QE (15 mg/kg bw day, intraperitoneal (i.p.) injection) was injected for 3 days prior to STZ administration; these injections were continued to the end of the study (for 25 days). Glucose tolerance test and random plasma glucose were done for all animals. Cellular antioxidant enzymes such as glutathione peroxidase (GSHPx), superoxide dismutase (SOD) and catalase (CAT) activities were measured in pancreatic homogenates. Quercetin had no effect on plasma glucose level of normal animals but its pre- treatment was able to prevent diabetes induced by single intraperitoneal injection of streptozocintreated rats. Antioxidant enzyme activity significantly decreased in STZ induced diabetic group. QE treatment significantly increased the antioxidant enzyme activities. It could be concluded that quercetin, a flavonoid with antioxidant properties, exerting its beneficial antidiabetic effects.  相似文献   

Reciprocal relationships between math self-concept and math anxiety     

Wondimu Ahmed  Alexander Minnaert  Hans Kuyper  Greetje van der Werf 《Learning and individual differences》2012,22(3):385-389

The present study examined the reciprocal relationships between self-concept and anxiety in mathematics. A sample of 495 grade 7 students (51% girls) completed self-report measures assessing self-concept and anxiety three times in a school year. Structural equation modeling was used to test a cross-lagged panel model of reciprocal effects between math self-concept and math anxiety. The analysis showed a reciprocal relationship between self-concept and anxiety in math (i.e., higher self-concept leads to lower anxiety, which in turn, leads to higher self-concept). However, the magnitude of the path from anxiety to self-concept is almost half of that from self-concept to anxiety. Overall, the results provide empirical support for the theoretical notion that math self-concept and math anxiety are reciprocally related.  相似文献   

Spirituality in the academy: reclaiming from the margins and evoking a transformative way of knowing the world     

Riyad Ahmed Shahjahan 《International journal of qualitative studies in education》2013,26(6):685-711

In this paper, the author's first and foremost objective is to render the answer to the following question: Why is spirituality marginalized in the academy? The author searches for the answer to this question in the terrain of knowledge production and worldviews that permeate the Western academy. The author examines the landscape of the neo‐colonial academy and delineates the conditions that restrict the spaces for spirituality. The author's second objective is to explore possible answers to the following question: How would centering spirituality transform our ways of knowing? The author attempts to answer this question by providing some preliminary ideas on the question of epistemology, methodology and methods in a spiritually based inquiry. The author concludes that this journey is endless and this paper is just a stepping stone to the discussion revolving around the integration and centering of spirituality within the academy.  相似文献