1,321 research outputs found

    Effect of Feeding Frequency and Stocking Density on Tilapia Oreochromis Niloticus and Lettuce Lactuca Sativa Production in Aquaponics System under the UAE Condition and Business Enterprise Analysis

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    This thesis was carried out to investigate the impact of various Tilapia (Oreochromisniloticus) feeding frequency and stocking density on quality and quantity of organic lettuce that is produced in an aquaponic system, knowing that they affect the nutrient content in water. Business analysis through enterprise budget was developed considering different feeding frequency and stocking density of the fish to predict the business efficiency of the system, and the net incomes were as high as AED 34,394 and AED 46,637, respectively. On the other hand, lettuce was seeded in a culture raceway. The duration of the experiments was decided to be six months, which was divided into two parts to study each parameter, i.e. feeding frequency (Once, twice and three times per day) and stocking density (100,120,140 fishes per cubic meter). In parallel, the aquaponic system water quality (pH, temperature, total dissolved solids, dissolved Oxygen, total ammonia, nitrite, and nitrate) and water consumption were analyzed at specified intervals. Furthermore, fish and cultivated plant growth rate and total yield were analyzed at the first and last days of the experimental period. The purpose of that was to optimize the system feeding system and stocking from different approaches both agriculturally and economically. It was found that highest used feeding frequency and stocking density are recommended to achieve high profitabilit

    A Machine Learning Approach For Opinion Holder Extraction In Arabic Language

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    Opinion mining aims at extracting useful subjective information from reliable amounts of text. Opinion mining holder recognition is a task that has not been considered yet in Arabic Language. This task essentially requires deep understanding of clauses structures. Unfortunately, the lack of a robust, publicly available, Arabic parser further complicates the research. This paper presents a leading research for the opinion holder extraction in Arabic news independent from any lexical parsers. We investigate constructing a comprehensive feature set to compensate the lack of parsing structural outcomes. The proposed feature set is tuned from English previous works coupled with our proposed semantic field and named entities features. Our feature analysis is based on Conditional Random Fields (CRF) and semi-supervised pattern recognition techniques. Different research models are evaluated via cross-validation experiments achieving 54.03 F-measure. We publicly release our own research outcome corpus and lexicon for opinion mining community to encourage further research

    Process Planning for Assembly and Hybrid Manufacturing in Smart Environments

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    Manufacturers strive for efficiently managing the consequences arising from the product proliferation during the entire product life cycle. New manufacturing trends such as smart manufacturing (Industry 4.0) present a substantial opportunity for managing variety. The main objective of this research is to help the manufacturers with handling the challenges arising from the product variety by utilizing the technological advances of the new manufacturing trends. This research focuses mainly on the process planning phase. This research aims at developing novel process planning methods for utilizing the technological advances accompanied by the new manufacturing trends such as smart manufacturing (Industry 4.0) in order to manage the product variety. The research has successfully addressed the macro process planning of a product family for two manufacturing domains: assembly and hybrid manufacturing. A new approach was introduced for assembly sequencing based on the notion of soft-wired galled networks used in evolutionary studies in Biological and phylogenetic sciences. A knowledge discovery model was presented by exploiting the assembly sequence data records of the legacy products in order to extract the embedded knowledge in such data and use it to speed up the assembly sequence planning. The new approach has the capability to overcome the critical limitation of assembly sequence retrieval methods that are not able to capture more than one assembly sequence for a given product. A novel genetic algorithm-based model was developed for that purpose. The extracted assembly sequence network is representing alternative assembly sequences. These alternative assembly sequences can be used by a smart system in which its components are connected together through a wireless sensor network to allow a smart material handling system to change its routing in case any disruptions happened. A novel concept in the field of product variety management by generating product family platforms and process plans for customization into different product variants utilizing additive and subtractive processes is introduced for the first time. A new mathematical programming optimization model is proposed. The model objective is to provide the optimum selection of features that can form a single product platform and the processes needed to customize this platform into different product variants that fall within the same product family, taking into consideration combining additive and subtractive manufacturing. For multi-platform and their associated process plans, a phylogenetic median-joining network algorithm based model is used that can be utilized in case of the demand and the costs are unknown. Furthermore, a novel genetic algorithm-based model is developed for generating multi-platform, and their associated process plans in case of the demand and the costs are known. The model\u27s objective is to minimize the total manufacturing cost. The developed models were applied on examples of real products for demonstration and validation. Moreover, comparisons with related existing methods were conducted to demonstrate the superiority of the developed models. The outcomes of this research provide efficient and easy to implement process planning for managing product variety benefiting from the advances in the technology of the new manufacturing trends. The developed models and methods present a package of variety management solutions that can significantly support manufacturers at the process planning stage

    Perceptions of Egyptian ESL teachers of teaching aspects of the target culture: The case of culturally-oriented speech acts in textbooks

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    The study explores issues related to the place of the target culture in the context of teaching English as a foreign/second language in Egypt. There are two research questions in this study. The first one is concerned with identifying the speech acts taught in the Hello! textbook studied by Egyptian students in all governmental and private schools of the third year of General Secondary Education. The second research question investigated the perceptions of governmental and private school teachers on teaching aspects of the target culture in their English classes in Egyptian schools. The research is of a quantitative/qualitative nature. A critical analysis of the speech acts activities from the Hello! textbook has been provided and it was found that only six units out of 18 in the Hello! textbook contain information on speech acts. These six speech acts are: giving advice, making and responding to suggestions, expressing wishes and regrets, offer to help, giving and responding to warnings, and persuading. Using a teacher questionnaire, data from 50 participants teaching at governmental and private schools in Egypt has been collected. This data was supplemented by interviews with three teachers from each type of school for a total of six teachers. The results reported from the questionnaire are in the form of statistics while those reported from the interviews are in the form of descriptive analysis. The results of the study show that the teaching of the target culture and pragmatics in ESL classes in Egypt is neglected due to many reasons, which include the lack of facilities and resources available to teachers, the use of a standardized high school exit exam which does not include questions on cultural aspects, and the resultant washback effect on teachers\u27 and students\u27 attitude toward the inutility of teaching cultural aspects

    Novel inhibitors of 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) and steroid sulfatase (STS) with unique dual mode of action : potential drugs for the treatment of non-small cell lung cancer (NSCLC) and endometriosis

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    Estrogens, in particular estradiol‎ (E2)‎ play an important role in estrogen-dependent diseases (EDDs), such as non-small-cell lung cancer ‎‎(NSCLC) and endometriosis. 17β-Hydroxysteroid dehydrogenase type 1 (17β-HSD1) is frequently expressed in NSCLC tissues, leading to cancer development and progression. Thus, the first objective of this study (chapter 3.1) is the development of a novel series of highly potent non-steroidal, selective ‎‎17β-HSD1 inhibitors in order to enhance the treatment of NSCLC. ‎ This section of the study showed that 17β-HSD1 is a promising therapeutic target for NSCLC, providing new avenues for the treatment of this lethal cancer. Steroid sulfatase (STS) and 17β-HSD1 are promising targets for the treatment of endometriosis because they ‎limit estrogen formation mainly in the target cells, leading to fewer ‎side effects. ‎Thus, the second part of the study ‎(chapter 3.2) ‎aims at developing dual inhibitors of STS and 17β-HSD1, which provide a novel treatment option. The synthesized sulfamates should be drugs for inhibition of STS, and prodrugs for 17β-HSD1 inhibition. The most active compounds of this part showed nanomolar IC50 values for STS in cellular assays ‎and their corresponding phenols displayed potent 17β-HSD1 inhibition in cell-free and cellular ‎assays as well as high selectivity over 17β-HSD2. These findings suggest that the “drug-prodrug concept” ‎has been applied successfully ‎(chapter 3.2).Estrogene, insbesondere Estradiol (E2), spielen eine zentrale Rolle bei Estrogen-abhängigen Erkrankungen (estrogen-dependent diseases, EDD) wie nicht-kleinzellige Bronchialkarzinome (non-small-cell lung cancer, NSCLC) und Endometriose. 17β-Hydroxysteroid Dehydrogenase Typ 1 (17β-HSD1) ist in NSCLC-Gewebe häufig überexprimiert und trägt zu Tumorentstehung und -wachstum bei. Das erste Ziel dieser Arbeit war daher die Entwicklung von neuartigen und hochpotenten, nicht-steroidalen 17β-HSD1 Inhibitoren als potenzielle NSCLC-Therapeutika (Kapitel 3.1). Die Daten zeigen, dass 17β-HSD1 ein vielversprechendes Target darstellt, das neue Möglichkeiten in der NSCLC-Therapie eröffnen kann. Steroid Sulfatase (STS) und 17β-HSD1 sind vielversprechende Wirkstofftargets zur Behandlung der Endometriose, da sie die E2-Produktion lokal im erkrankten Gewebe reduzieren, was im Vergleich zu systemischen Therapien zu weniger Nebenwirkungen führen sollte. Gegenstand des zweiten Teils der Arbeit (Kapitel 3.2) war die Entwicklung von dualen Inhibitoren von STS und 17β-HSD1. Die so synthetisierten Sulfamate sollten Drugs für die Hemmung von STS und gleichzeitig Prodrugs für die Hemmung von 17β-HSD1 darstellen. Die aktivsten Verbindungen dieses Teils zeigten nanomolare IC50-Werte für STS in zellulären Assays und ihre entsprechenden Phenole zeigten eine starke 17β-HSD1-Hemmung in zellfreien und zellulären Assays sowie eine hohe Selektivität gegenüber 17β-HSD2. Die Daten belegen, dass das verfolgte “Drug-Prodrug-Konzept” der dualen Hemmstoffwirkung erfolgreich umgesetzt wurde (Kapitel 3.2)

    Dynamic Feedback Flow Control Algorithms for Unicast and Multicast Available Bit Rate Service in Asynchronous Transfer Mode Networks

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    Asynchronous transfer mode (ATM) network technology has been adopted to integrate different kinds of traffic, like video, audio and data. It provides several service categories including constant bit rate (CBR), variable bit rate (VBR), available bit rate (ABR), and unspecified bit rate (UBR) service. In particular, the ABR service has been approved to use the bandwidth left by CBR and VBR services, which is ideal for data applications and can perform well for real-time applications with the appropriate implementation. Basically ABR servIce attempts to guarantee minimum cell rate, achieve fairness, and minimise cell loss by periodically indicating to sources the rate at which to send. Therefore, there is a critical need for an effective flow control mechanism to allocate network resources (buffers, bandwidth), and provide the negotiated quality of service. This thesis develops dynamic feedback flow control schemes in ATM networks, with primary focus on point-to-point (unicast) and point-tomUltipoint (multicast) ABR algorithms. Firstly, it surveys a number of point-to-point schemes proposed for supporting unicast ABR service. Some of these algorithms do not measure the actual ABR traffic load which leads to either overestimates or underestimates of the bandwidth allocation. Others do not monitor the activity of the sources and overlook the temporarily idle sources. The rest may be implemented with additional complexity. Secondly, the research shifts to the problems of point-to-multipoint algorithms by introducing the basic concept of multicasting ABR servIce and reviewing a group of consolidation schemes, where the compromise between low consolidation nOlse and fast transient response is the main issue. Thirdly, the design and implementation issues have been addressed together with the major drawbacks of the previous schemes and hence two algorithms have been proposed. A dynamic rate-based flow control (DRFC) scheme has been developed to support ABR service in unicast environment, while an adaptive feedback consolidation (AFC) algorithm has been designed for ABR multicasting. Finally, these schemes are extensively tested and compared with others from the literature using a wide range of network configurations and different types of traffic sources. The simulation results show that the DRFC algorithm allocates the available bandwidth fairly among the contending ABR sources, while achieving high link utilisation with reasonable growth of queues. The AFC scheme eliminates the consolidation noise with fast transient response as well as minimising the effect of non-responsive branches

    Integration Protocols for Voice and Data Traffic

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    Increasing demands for multimedia services offer integration of multimedia traffic as a hot issue in the future research areas. As a result, in the literature, many multiplexing schemes have been proposed. However, most of them have been implemented with a high complexity, others may be non-effective to satisfy the multiplexing performance criteria, while the rest are still not subjected to a wide range of analysis. Therefore, there is a critical need for comparing some of the recommended multiplexing schemes as well as developing a simple and effective integration protocol while still achieving reasonable bandwidth utilization. This thesis is intended to examine integration protocols for multimedia traffic, with primary focusing on voice-data integration. Firstly, a survey of the existing multiplexing schemes and related issues are presented. Next, an Adaptive Round Robin (ARR) protocol is proposed, as an alternative for voice-data integration, and extensively simulated. Finally, further comparisons, based on computer simulations, are carried out for various multiplexing schemes including Strictly Priority Servicing (SPS), Fixed Round Robin (FRR), Dynamic Bandwidth Allocation/(T1, T2) and Queue Length Threshold (QLT).As a contribution of the thesis, the proposed protocol tries to avoid the drawbacks of the previous multiplexing schemes besides satisfying the multiplexing performance criteria. The protocol differs from the others in that, it gives a limited priority for voice over data, it organizes the incoming packets to the single First-in First-out (FIFO) output buffer rather than the only outgoing scheduling, i.e., all data sources are polled in order according to the adaptation policy; however, before a data source can send a packet, all active voice sources are polled in order. Thus it provides an improvement in voice delay performance without significant effect on data delay performance over previous protocols. In addition, simulation comparisons between various multiplexing schemes have been discussed. In these simulations voice packets are assumed to be generated from on-off sources (talkspurt-silence calls), which is closer to reality and which is not considered in most of the performance analyses of previous schemes

    A Correlative Developmental Study of Structures Involved in the Production, Circulation and Removal of Cerebrospinal Fluid

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    The development of the choroid plexus, the IVth ventricular foramina and subarachnoid space has been studied by optical microscopy and morphometric analysis of semi-thin plastic sections and by TEM and SEM in a series of CBA mouse embryos from 11th day p. c. to newborn. 1. Choroid plexus of the IVth ventricle At the 11th day p. c. the choroid epithelial cells were already recognisable in SEM by their bulging apices and relatively abundant microvilli; their lateral plasma membranes, as shown by TEM, were straight and simple. The tela choroidea was more vascular in relation to this specialised epithelium but invagination into the ventricle had not yet begun. By the 13 th day p. c. important qualitative changes had taken place: The apical surfaces of choroid epithelial cells were densely covered by microvilli and their basilateral plasma membranes showed complex infoldings and interdigitations. These two features together with cytoplasmic organelles (mitochondria, rough endoplasmic reticulum, Golgi complex) were essentially similar between 13th day p. c. and birth. Although there was an apparent increase in the size of the choroid plexus from the time of its first appearance, no significant progressive changes were found in the volume densities of its components (epithelium, blood vessels and connective tissue) during prenatal development. The structural evidence is consistent with functional secretory capacity of the plexus from the 13th day p. c. SEM showed the IVth ventricular choroidal "capillaries" to be sinusoidal in nature, and clearly different from those of adjacent subependymal cerebral capillaries, and also surprisingly, those of the lateral ventricle choroid plexus. Although they remain sinusoidal until birth, their endothelial lining was shown by TEM to become progressively and uniformly thinner and to contain an increasing number of fenestrae as development progressed. The endothelial basement membrane was ill-defined and poorly developed throughout development. The choroidal capillaries also became more intimately related to the epithelium as development proceeded. All these features of endothelium would facilitate the movement of substances across the capillary wall. 2. Foramina of the IVth ventricle Although the caudal part of the roof of the IVth ventricle remained extremely attenuated throughout development, no foramina or interependymal pores were found. The ependymal lining of the lateral recesses started to attenuate by the 17th day p. c. but lateral foramina did not appear until birth. The lateral foramina seemed to arise as the result of an active developmental process and not merely through the rupture of the ependymal wall by the CSF pressure. The ventricular cavity was therefore an anatomically closed one until the appearance of the lateral foramina at birth when bulk flow of CSF from the ventricular cavity into the subarachnoid space was first established. 3. The subarachnoid space At the 11th day p. c. , a vascular cellular mesenchyme occupied the entire interval between the neuroepithelium and the future epidermis. At the 13th day p. c. , the small, spindle-shaped mesenchymal cells were becoming widely separated, in some symmetrically placed areas around the brain, by abundant intercellular matrix. Definite "spaces", presumably fluid-filled, were first seen at the 14th day p. c. , particularly over the lateral, ventral and dorsolateral aspects of the hind brain, but not on the dorsal aspect, adjacent to the thin roof of the IVth ventricle. The appearance of the subarachnoid spaces coincided with the appearance of a large number of macrophages in these spaces. The significance of this association is discussed. Contrary to previously held views, it was concluded that bulk flow of CSF does not initiate the development of the subarachnoid space. 4. Arachnoid villi Arachnoid villi were not present in the mouse, but the supporting dura was found to be a thin layer with loosely and randomly oriented fibres. This thin supporting dural layer is apparently adequate for the support of the small size mouse brain and at the same time allows CSF to percolate through from the subarachnoid space to reach the venous sinuses without the need for arachnoid villi
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