337 research outputs found

    Cooperative Key Establishment Protocol for Full-Duplex Relay Systems

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    Using the fading channel characteristics, as a randomness source, for the secret key generation earns significant attention because of it’s computational less power and low energy consumption. Current researches focus on point-to-point reciprocal-based key extraction from these randomness sources. Most practical communication situations are non-line of sight, so endpoints use a relaying channel to improve communication performance. Besides that, in the upcoming 5G systems, the full-duplex (FD) communications will be one of the main techniques, which will remove the advantage of using the reciprocal feature in the randomness source common observation. In this paper, we consider the challenge of generating a symmetric secret key between two legitimate parties in the relaying channel with FD capability. We suggest an efficient key extraction protocol that accomplished an acceptable shared secret key rate compared to the direct channel traditional approach. Unlike similar schemes, we provide full statistical analysis for the construction of randomness source from the relaying channel with FD capability. Additionally, we investigate the performance analysis of the suggested key agreement protocol. We also analyze the effect of the curious-but-honest relay and an eavesdropper on the proposed protocol

    Automatic Segmentation of Optic Disc in Eye Fundus Images: A Survey

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    Optic disc detection and segmentation is one of the key elements for automatic retinal disease screening systems. The aim of this survey paper is to review, categorize and compare the optic disc detection algorithms and methodologies, giving a description of each of them, highlighting their key points and performance measures. Accordingly, this survey firstly overviews the anatomy of the eye fundus showing its main structural components along with their properties and functions. Consequently, the survey reviews the image enhancement techniques and also categorizes the image segmentation methodologies for the optic disc which include property-based methods, methods based on convergence of blood vessels, and model-based methods. The performance of segmentation algorithms is evaluated using a number of publicly available databases of retinal images via evaluation metrics which include accuracy and true positive rate (i.e. sensitivity). The survey, at the end, describes the different abnormalities occurring within the optic disc region

    A stochastic Model for Predicting Irrigation Water Requirements (IWR)

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    The main objective of this paper is to develop a stochastic time series model with trend, periodic and irregular components using a ten years IWR decade data for three different types of cotton crops cultivated in Gezira Scheme, SUDAN. The model was applied to cotton Brackat and then used to Shmbat & Akala cotton. In the analysis of IWR time series the correlogram technique was used to detect the periodicity which then smoothed by Fourier series method. The series is then tested for stationary and the dependent part of irregular component is found to be well expressed by the first order autoregressive model for all the crops. The developed model superimposes a periodic-deterministic process and an irregular componen

    Identification and characterization of microRNAs and their putative target genes in Anopheles funestus s.s

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    Philosophiae Doctor - PhDThe discovery of microRNAs (miRNAs) is one of the most exciting scientific breakthroughs in the last decade. miRNAs are short RNA molecules that do not encode proteins but instead, regulate gene expression. Over the past several years, thousands of miRNAs have been identified in various insect genomes through cloning and sequencing, and even by computational prediction. However, information concerning possible roles of miRNAs in mosquitoes is limited. Within this context, we report here the first systematic analysis of these tiny RNAs and their target mRNAs in one of the principal African malaria vectors, Anopheles funestus s.s. Firstly, to extend the known repertoire of miRNAs expressed in this insect, the small RNAs from the four developmental stages (egg, larvae, pupae and the adult females), were sequenced using next generation sequencing technology. A total of 98 miRNAs were identified, which included 65 known Anopheles miRNAs, 25 miRNAs conserved in other insects and 8 novel miRNAs that had not been reported in any species. We further characterized new variants for miR-2 and miR-927 and stem-loop precursors for miR-286 and miR-2944. The analysis showed that many miRNAs have stage-specific expression, and co-transcribed and co-regulated during development. Secondly, for a better understanding of the molecular details of the miRNAs function, we identified the target genes for the Anopheles miRNAs using a novel approach that identifies overlap genes among three target prediction tools followed by filtering genes based on functional enrichment of GO terms and KEGG pathways. We found that most of the miRNAs are metabolic regulators. Moreover, the results suggest implication of some miRNAs not only in the development but also in insect-parasite interaction. Finally, we developed the InsecTar database (http://insectar.sanbi.ac.za) for miRNA targets in the three mosquito species; Anopheles gambiae, Aedes aegypti, and Culex quinquefasciatus, which incorporates prediction and the functional analysis of these target genes. The proposed database will undoubtedly assist to explore the roles of these regulatory molecules in insects. This type of analysis is a key step towards improving our understanding of the complexity and regulationmode of miRNAs in mosquitoes. Moreover, this study opens the door for exploration of miRNA in regulation of critical physiological functions specific to vector arthropods which may lead to novel approaches to combat mosquito-borne infectious diseases

    Automatic Segmentation of Optic Disc in Eye Fundus Images : a Survey

    Get PDF
    Optic disc detection and segmentation is one of the key elements for automatic retinal disease screening systems. The aim of this survey paper is to review, categorize and compare the optic disc detection algorithms and methodologies, giving a description of each of them, highlighting their key points and performance measures. Accordingly, this survey firstly overviews the anatomy of the eye fundus showing its main structural components along with their properties and functions. Consequently, the survey reviews the image enhancement techniques and also categorizes the image segmentation methodologies for the optic disc which include property-based methods, methods based on convergence of blood vessels, and model-based methods. The performance of segmentation algorithms is evaluated using a number of publicly available databases of retinal images via evaluation metrics which include accuracy and true positive rate (i.e. sensitivity). The survey, at the end, describes the different abnormalities occurring within the optic disc region

    The DFT+U: Approaches, Accuracy, and Applications

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    This chapter introduces the Hubbard model and its applicability as a corrective tool for accurate modeling of the electronic properties of various classes of systems. The attainment of a correct description of electronic structure is critical for predicting further electronic-related properties, including intermolecular interactions and formation energies. The chapter begins with an introduction to the formulation of density functional theory (DFT) functionals, while addressing the origin of bandgap problem with correlated materials. Then, the corrective approaches proposed to solve the DFT bandgap problem are reviewed, while comparing them in terms of accuracy and computational cost. The Hubbard model will then offer a simple approach to correctly describe the behavior of highly correlated materials, known as the Mott insulators. Based on Hubbard model, DFT+U scheme is built, which is computationally convenient for accurate calculations of electronic structures. Later in this chapter, the computational and semiempirical methods of optimizing the value of the Coulomb interaction potential (U) are discussed, while evaluating the conditions under which it can be most predictive. The chapter focuses on highlighting the use of U to correct the description of the physical properties, by reviewing the results of case studies presented in literature for various classes of materials

    Alleviating Air Pollutants Impact by Some Chemicals and Planting Distance off the Freeway and Their Effect on Pears Productivity and Fruit Quality

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    The goal of this study was to determine the effectiveness of exogenous application of some chemicals [Salicylic acid (SA; 200 and 400 mg/l), Ascorbic acid (AA; 1000 and 2000 mg/l), Proline (Pro; 100 and 200 mg/l), and Sodium hydrosulfide (NaHS; 250 and 500 M)] as well as planting distances (10 and 50 meters off the freeway) in alleviating air pollutants stress on "Le Conte" productivity and fruit quality of pears. During the 2019 & 2020 seasons, a study was accomplished at the 6th of October Agriculture Company. SA, AA, proline, and NaHS had a positive effect on reducing the fruit heavy metal content for the pear trees under stress. Also, SA (400 mg/l), AA, Pro (100 mg/l), and NaHS (500 μM) treatments were very helpful in increasing the tolerance index for air pollution (APTI) in pear leaves. Exogenous application of Pro, SA (200 mg/l), and AA (2000 mg/l) increased Pro in leaves. Pear trees' yield, fruit firmness, TSS, TSS/acid, V.C., total sugars, total phenolics, antioxidants, peroxidase, and superoxide dismutase were increased. Fruit from trees planted at 10 m deferred in ripening and had higher total phenolics, antioxidants, peroxidase, and superoxide dismutase

    Chicory abrogates oxidative stress, inflammation and caspase-dependent apoptosis in acute hepatic injury model induced by acetaminophen in rats

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    In this study the protective effect of chicory leaves hydroalcoholic extract (CIE) against acute liver injury induced by a single dose of acetaminophen (700 mg/kg, i.p.) was investigated in rats. The CIE and silymarin treatment (standard reference) were given in a dose of (100 mg/kg, p.o.) for 3 days before and at 1 and 12 h following acetaminophen administration. Treatment with CIE significantly reduced the levels of serum ALT, AST, alkaline phosphatase, bilirubin, total cholesterol, triglycerides, urea, creatinine, TNF-α and hepatic contents of malondialdehyde (MDA), nitric oxide, caspase-3 and hydroxyproline, with significant increases in serum total protein, albumin, HDL- cholesterol and hepatic activities of reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) as compared with the acetaminophen group. The histopathological alterations mediated by acetaminophen were ameliorated by CIE. It was concluded that CIE protects rat liver against acetaminophen hepatotoxicity, most probably through abrogation of oxidative stress, inflammation and caspase-3 dependent apoptosis

    The association of hamstring tightness with lumbar lordosis and trunk flexibility in healthy individuals: gender analysis

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    Objectives: The purpose of this study was to investigate if there is a relation between hamstring tightness and lumbar lordosis as well as trunk flexibility based on gender differences and to analyze the differences in hamstring tightness, lumber lordosis and trunk flexibility in healthy adults.Methods: One hundred young healthy adults were recruited and distributed into 2 equal groups according to gender: group A (female group) and group B (male group). Hamstring tightness (HT) was measured by Active Knee Extension (AKE) test and Straight Leg Raise (SLR) test, the angle of lumbar lordosis was measured with a flexible ruler from standing position and trunk flexion flexibility (TFF) was measured by Fingertip-to-Floor Test.Results: There was a significant correlation between TFF and both measures of HT (SLR, p = 0.001; AKE, p = 0.001) in females. While, there was a non-significant correlation in males (SLR, p = 0.900; AKE, p = 0.717). Moreover, there was a non-significant correlation between lumbar lordosis and HT measures in both groups as (p > 0.05). Furthermore, there were significant differences between males and females in hamstring flexibility, TFF and lumbar lordosis as (p < 0.05).Conclusion: Gender differences in the relationship between hamstring tightness and trunk flexion flexibility are significant. However, there was no significant difference between males and females in the relationship between hamstring tightness and lumbar lordosis
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