1,808 research outputs found

    An assessment of the impact of human activities on wild birds and fishes in Dagona Waterfowl Sanctuary, Nigeria

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    Natural resources management and conservation has been a persistent theme in discourse of human survival and environmental development. Conservation means the sustainable use and protection of natural resources. It is also seen as the process through which natural resources are  managed to allow partial or total exploitation for individual, community, or commercial use without jeopardizing the long-term ability of the  resource base for future generations with minimal environmental damages. The study employed systematic sampling techniques in selecting the respondents for the interview. The selection was based on the settlement arrangement in the study site as sampling frame. The structured  questionnaires were administered to the respondents with aid of research assistant for proper interpretation of the questionnaire to local language (Bade). The study found that there were different bird species both native and migratory birds from Europe and other parts of the world. The use of these birds includes tourism, source of meat, income and beautification of the natural environment. Farming hunting and fishing remain the dominant economic activities that provide income, food and tourism in the area. Hunting and fishing reduces the number as well as the  composition of birds and fish species in the area. Protopterrus annectens and Egretta garzetta were the dominant fish and bird species respectively. A lot of efforts were made to conserve and protect the waterfowl against natural and anthropogenic effects from national and international  environmental concern organizations. Key words: natural resource, human activities impact, wild birds, fishes, Dagona Waterfowl Sanctuar

    Prediction of water table in an alluvial aquifer using modflow

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    Groundwater is the main source of water in the Kingdom of Saudi Arabia (KSA). A larger part of groundwater is founded in alluvial (unconfined) aquifers. Prediction of water table elevations in unconfined aquifers is very useful in water resources planning and management. During the last two decades, many aquifers in different regions of the KSA experienced significant groundwater decline. The declines in these aquifers raised concerns over the quantity and quality of groundwater, as well as concerns over the planning and management policies used in KSA. The main objective of this study was to predict water table fluctuations and to estimate the annual change in water table at an alluvial aquifer at wadi Hada Al Sham near Makkah, KSA. The methodology was achieved using numerical groundwater model (MODFLOW). The model was calibrated and then used to predict water table elevations due to pumping for a period of 5 years. The output of the model was found to be in agreement with the previous records. Moreover, the simulation results also show reasonable declination of water table elevations in the study area during the study period

    Detour Polynomials of Generalized Vertex Identified of Graphs

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    تعد مسافة الالتفاف من أهم أنواع المسافات التي لها تطبيقات حديثة في الكيمياء وشبكات الكمبيوتر، لذلك حصلنا في هذا البحث على متعددات حدود الالتفاف وأدلتها لـ  nمن البيانات المنفصلة عن بعضها البعض بالنسبة للرؤوس ، n≥3. أيضًا وجدنا متعددات حدود الالتفاف وأدلتها لبعض البيانات الخاصة والتي لها تطبيقات مهمة في الكيمياء.The Detour distance is one of the most common distance types used in chemistry and computer networks today. Therefore, in this paper, the detour polynomials and detour indices of vertices identified of n-graphs which are connected to themselves and separated from each other with respect to the vertices for n≥3 will be obtained. Also, polynomials detour and detour indices will be found for another graphs which have important applications in Chemistry.

    Adaptive E-Learning Based on Learner's Styles

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    In this paper, a new model for adaptive e-learning based on learner's styles is presented. In the previous work, the dimensions of learner's styles given by Felder-Silverman did not consider some important issues of the learner himself. Here, new learner's parameters such as his social environment, health conditions, psychological and economical states are taken into account. Such parameters greatly affect the ability of student to learn and understand. Therefore, in order to perfectly recognize the ability of the student to be interactive in the leaning environment and accept information, new learner's styles are added to the dimensions of Felder-Silverman learning style model and our previous work [24]. The new proposed model is applied for logic gates and functions used in data encoding and computer networks. Such model presents suitable courses for each student in a dynamic and adaptive manner using existing database and workflow technologies. Furthermore, it is powerful, user friendly and easy to interpret. Moreover, it suggests a learning strategy and appropriate electronic media that match the learner’s preference

    Flash flood susceptibility assessment in Jeddah city (Kingdom of Saudi Arabia) using bivariate and multivariate statistical models

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    The city of Jeddah (Saudi Arabia) has experienced two catastrophic flash flood events in 2009 and 2011. These flood events had catastrophic effect on human lives and livelihoods around the wadi Muraikh, wadi Qus, wadi Methweb, and wadi Ghulail in which 113 people were dead and with 10,000 houses and 17,000 vehicles were damaged. Thus, a comprehensive flood management is required. The flood management requires information on different aspects such as the hydrological, geotechnical, environmental, social, and economic aspects of flooding. Flood susceptibility mapping for any area helps the decision makers to understand the flood trends and can aid in appropriate planning and flood prevention. In this study, two models were used for the generation of flood susceptibility maps for the Jeddah region. The first model includes bivariate probability analysis (frequency ratio), and the second model uses the multivariate analysis. For the multivariate model, the acquired weights of the FR model were entered into the logistic regression model to evaluate the correlation between flood occurrence and each related factor. This integration will overcome some of the weakness of the logistic regression, and the performance the LR will be enhanced. A flood inventory map was prepared with a total of 127 flood locations. These flood locations were extracted from different sources including field investigation and high-resolution satellite image (IKONOS 1 m). These flood locations were randomly split into two groups, one dataset representing 70 % was used for training the models, and the remaining 30 % was used for models validation. Various independent flood-related factors such as slope, elevation, curvature, geology, landuse, soil drain, and distance from streams were included. The impact of each independent flood-related factors on flooding was evaluated by analyzing each independent factor with the historical flood inventory data. The training and validation datasets were used to evaluate the flood susceptibility maps using the success and the prediction rate methods. The results of the accuracy assessment showed a success rate of 90.4 and 91.6 % and a prediction rate of 89.6 and 91.3 % for FR and ensemble FR and LR models, respectively. In addition, a comparison has been made between real flood events in 2009 and the resultant susceptibility maps. Hence, it is concluded that the FR and ensemble Fr and LR models can provide an acceptable accuracy in the prediction of flood susceptibility in the Saudi Arabia. Our findings indicated that these flood susceptibility maps can assist planners, decision makers, and other agencies to deal with the flood management and planning in the area

    Remote sensing-based studies coupled with field data reveal urgent solutions to avert the risk of flash floods in the Wadi Qus (east of Jeddah) Kingdom of Saudi Arabia

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    On November 25, 2009, heavy amount of rainfall precipitated in the city of Jeddah that led to floods causing unexpected loss of life (113 person died), and damaged public and private properties (10,000 cars were damaged/destroyed, and many houses, roads, highways, and industrial properties were also affected). The city of Jeddah is located within an independent mega drainage basin with a surface area of 1,760 km2. This mega basin is divided into three major sub-basins (northern, middle, and southern). Wadi Qus is located in the southern sub-basin with an area of ~63 km2. It passes through many of the neighborhoods such as Al-Harazat, Al-Sawaid, Queza, Al-Mesaid, Al-Haramin Highway, and the King Abdel Aziz University. These areas were severely damaged during the flash flood event in 2009. The current study deals with the determination of the best sites for the construction of flood control dams, followed by a number of detailed studies to ensure that these selected sites are appropriate. Geological, geotechnical, geophysical, and hydrological investigations were conducted to identify the types of rocks, the subsurface conditions, and the geotechnical properties of abutment and subsurface of soil and rock in the dam sites. The study found that there are three locations that can be appropriate for the construction of the flood control dams at Wadi Qus. Hydrological studies indicated that the runoff volumes for sub-basins B1, B2, and B3 are 2,102,709, 1,023,156, and 4,868,304 m3, respectively, for 500-year return period and 2,356,081, 1,149,687, and 5,451,123 m3, respectively, for 1,000-year return period. Comparing these values with the reservoir volumes calculated from the detailed ground survey with different dam’s height, it was found that dam’s heights of 15.5, 11.5, and 13.5 m for dams Q01, Q02, and Q03, respectively, are adequate for different basin volumes for 1,000-year return periods. Finally, the conceptual designs have been prepared and recommended for these dams

    Simulation of flow over stepped and traditional spillways

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    There are several challenges that are faced by these structures, such as cavitation and high speed of flow during the dissipation of flow energy. The spillway is one of the key basic elements of dams that are utilized to pass huge volumes of discharge. The current work used computational fluid dynamics (CFD) to numerically estimate the water surface flow and pressure distribution over stepped and traditional spillways. The numerical findings were compared with experimental data using the Renormalization group k- model. The numerical and experimental data have been compared, and it has been determined that there is an acceptable agreement between the two sets of findings

    Nonenzymatic Exogenous and Endogenous Antioxidants

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    Nonenzymatic exogenous and endogenous antioxidants play an important role in human health and act as preservatives for cosmetics, pharmaceuticals, and food products. This chapter will discuss the chemical structure and mechanism of action of the most important nonenzymatic small exogenous and endogenous organic molecules that act as antioxidants. The chapter will focus on the structural features, functional groups, properties, biosynthetic origin, and mechanism of action of such antioxidants. It also covers damages that free radicals create and the mechanisms by which they are neutralized by the various antioxidants. The scope of this chapter will be limited to nonenzymatic exogenous and endogenous antioxidants since enzymatic antioxidants have been discussed extensively in several reviews
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