Causal Relationship Between Islamic Bonds, Oil Price and Precious Metals: Evidence From Asia Pacific

Sukuk or Islamic bonds as new “Halal” securities had wildly expanded in Muslim and non-Muslim capital markets. So, this study aims to investigate the causal relationship between Islamic bonds (sukuk), oil and precious metals “silver and gold” prices in Asia pacific. This study used VAR model relying on daily data. The findings of Granger causality test and impulse-responses analysis results provide substantial evidence in favor of the relation between sukuk and the commodity market variables (oil, gold, and silver) meanwhile and unlike many empirical studies, don\u27t we have found that oil doesn\u27t cause changes in precious metals prices. Therefore, the idea that Islamic financial markets provide diversification benefits and they are safe havens during oil crisis cannot be supported empirically.DOI: 10.15408/aiq.v10i2.717

Phylogeny and genetic recombination of Grapevine fanleaf virus isolates from naturally infected vineyards in Tunisia

The genetic diversity of Grapevine fanleaf virus (GFLV) was investigated in 11 isolates recovered from naturally infected vineyards located in the Cap Bon and Tunis regions. Virions were collected by immunocapture, and a 321 bp fragment containing part of the viral coat protein gene (CP) was amplifi ed by RT-PCR. Amplicons were cloned into a pMosBlue vector and sequenced. The evolutionary historical relationships were determined by constructing a dendrogram using Maximum-parsimony (MP), Maximum-Likelihood (ML) and Neighbor-Joining (NJ), all of which gave similar results. Besides phylogeny, recombination also explains a considerable amount of genetic diversity in natural populations. Recombinational events were detected by a variety of bioinformatic programs. Different recombination breakpoints were determined with a particularly strong signal located downstream nt 272 of the amplicon (the position in the CP gene as determined by the RECCO algorithm is: 456–467). Interestingly, it was found that recombination is widespread in the CP gene even though only a short part of the CP cistron was analyzed. As a result of this analysis, it appears that recombination may explain in part the great number of GFLV isolates described worldwide. Apart from recombination, reassortment is still an open question among many others, and may represent another way to explore the genetic diversity of GFLV

Molecular characterization of an almond isolate of Prune dwarf virus in Tunisia: putative recombination breakpoints in the partial sequences of the coat protein-encoding gene in isolates from different geographic origin

Recombination is an important driving force in evolution. To investigate this evolutionary process in Prune dwarf virus (PDV), 31 accessions retrieved from international databases, supplemented by one Tunisian isolate described here, were analyzed. Two recombination detection programs were used: RDP v3.31β and RECCO. While the first program did not detect any significant recombination events, RECCO detected several breakpoints in partial sequences of the coat protein gene (CP) of fifteen isolates. The Tajima neutrality test implemented in the MEGA4.1β program indicated that there were numerous deletion/insertion events in the sequences. The strongest signal was found in Portuguese isolate 3.12N.14 (accession number AY646846) which had position nt 296–523 in the CP gene. The evolutionary historical relationships between all analyzed isolates were determined by constructing a dendrogram using Neighbor joining (NJ), Minimum evolution (ME), Maximum parsimony (MP), Maximum likelihood (ML), and the Unweighted pair group method with arithmetic mean (UPGMA); all gave similar results. Two main clusters were delineated, one representing recombinant and one nonrecombinant isolates. The recombinant isolates were mostly collected from Portugal, whereas the nonrecombinant isolates originated in eastern Europe

Ensemble methods for instance-based Arabic language authorship attribution

The Authorship Attribution (AA) is considered as a subfield of authorship analysis and it is an important problem as the range of anonymous information increased with fast growing of internet usage worldwide. In other languages such as English, Spanish and Chinese, such issue is quite well studied. However, in Arabic language, the AA problem has received less attention from the research community due to complexity and nature of Arabic sentences. The paper presented an intensive review on previous studies for Arabic language. Based on that, this study has employed the Technique for Order Preferences by Similarity to Ideal Solution (TOPSIS) method to choose the base classifier of the ensemble methods. In terms of attribution features, hundreds of stylometric features and distinct words using several tools have been extracted. Then, Adaboost and Bagging ensemble methods have been applied on Arabic enquires (Fatwa) dataset. The findings showed an improvement of the effectiveness of the authorship attribution task in the Arabic language

A novel population-based local search for nurse rostering problem

Population-based approaches regularly are better than single based (local search) approaches in exploring the search space. However, the drawback of population-based approaches is in exploiting the search space. Several hybrid approaches have proven their efficiency through different domains of optimization problems by incorporating and integrating the strength of population and local search approaches. Meanwhile, hybrid methods have a drawback of increasing the parameter tuning. Recently, population-based local search was proposed for a university course-timetabling problem with fewer parameters than existing approaches, the proposed approach proves its effectiveness. The proposed approach employs two operators to intensify and diversify the search space. The first operator is applied to a single solution, while the second is applied for all solutions. This paper aims to investigate the performance of population-based local search for the nurse rostering problem. The INRC2010 database with a dataset composed of 69 instances is used to test the performance of PB-LS. A comparison was made between the performance of PB-LS and other existing approaches in the literature. Results show good performances of proposed approach compared to other approaches, where population-based local search provided best results in 55 cases over 69 instances used in experiments

Simulation de l'effet des surcharges sur le comportement mécanique des P.T.H à couples de matériaux différents

International audienceThe reliability of total hip arthroplasties (THA) is not any more to show. It is allowed by all. Indeed, the retreat of such interventions exceeds now fifteen years and the hopes which the first clinicians formulated are now realities. Nevertheless, the deformation and the wear of cup components remain an inevitable mechanism and loosening appear in long-term. Prevention of loosening passes by the reduction of this wear. This study deals with a simulation of the effect of overloads on THA with different materials. Three materials are analyzed in order to choose the couple which has better bio functionality.La fiabilité des arthroplasties totales de hanche n'est plus à démontrer. Elle est admise par tous. En effet, le recul de telles interventions dépasse maintenant quinze ans et les espérances que les premiers cliniciens ont formulées à leur égard sont maintenant des réalités. Néanmoins, la déformation et l'usure des composants acétabulaires restent un mécanisme inévitable et des descellements asceptiques apparaissent à long terme. La prévention du descellement passe donc par la réduction de cette usure. Cette étude porte sur une simulation de l'effet de certains paramètres mécaniques, entre autres « les surcharges » sur le comportement des PTH hybrides à couples de matériaux différents. Trois couples de matériaux sont analysés, en vue de choisir celui qui offre une meilleure biofonctionnalité

Late Maastrichtian carbon isotope stratigraphy and cyclostratigraphy of the Newfoundland Margin (Site U1403, IODP Expedition 342)

Earth’s climate during the Maastrichtian (latest Cretaceous) was punctuated by brief warming and cooling episodes, accompanied by perturbations of the global carbon cycle. Superimposed on a long-term cooling trend, the middle Maastrichtian is characterized by deep-sea warming and relatively high values of stable carbon-isotope ratios, followed by strong climatic variability towards the end of the Cretaceous. A lack of knowledge on the timing of climatic change inhibits our understanding of underlying causal mechanisms. We present an integrated stratigraphy from Integrated Ocean Drilling Program (IODP) Site U1403, providing an expanded deep ocean record from the North Atlantic (Expedition 342, Newfoundland Margin). Distinct sedimentary cyclicity suggests that orbital forcing played a major role in depositional processes, which is confirmed by statistical analyses of high resolution elemental data obtained by X-ray fluorescence (XRF) core scanning. Astronomical calibration reveals that the investigated interval encompasses seven 405-kyr cycles (Ma4051 to Ma4057) and spans the 2.8 Myr directly preceding the Cretaceous/Paleocene (K/Pg) boundary. A high-resolution carbon-isotope record from bulk carbonates allows us to identify global trends in the late Maastrichtian carbon cycle. Low-amplitude variations (up to 0.4‰) in carbon isotopes at Site U1403 match similar scale variability in records from Tethyan and Pacific open-ocean sites. Comparison between Site U1403 and the hemipelagic restricted basin of the Zumaia section (northern Spain), with its own well-established independent cyclostratigraphic framework, is more complex. Whereas the pre-K/Pg oscillations and the negative values of the Mid-Maastrichtian Event (MME) can be readily discerned in both the Zumaia and U1403 records, patterns diverge during a ~ 1 Myr period in the late Maastrichtian (67.8–66.8 Ma), with Site U1403 more reliably reflecting global carbon cycling. Our new carbon isotope record and cyclostratigraphy offer promise for Site U1403 to serve as a future reference section for high-resolution studies of late Maastrichtian paleoclimatic change

UAVs and Blockchain Synergy: Enabling Secure Reputation-based Federated Learning in Smart Cities

Unmanned aerial vehicles (UAVs) can be used as drones’ edge Intelligence to assist with data collection, training models, and communication over wireless networks. UAV use for smart cities is rapidly growing in various industries, including tracking and surveillance, military defense, managing healthcare delivery, wireless communications, and more. In traditional machine learning techniques, an enormous amount of sensor data from UAVs must be shared to central storage to perform model training, which poses serious privacy risks and risks of misuse of information. The federated learning technique (FL), which can be applied to UAVs, is a promising means of collaboratively training a global model while retaining local access to sensitive raw data. Despite this, FL is a significant communication burden for battery-constrained UAVs due to local model training and global synchronization frequency. In this article, we address the major challenges associated with UAV-based FL for smart cities, including single-point failure, privacy leakage, scalability, and global model verification. To tackle these challenges, we present a differentially private federated learning framework based on Accumulative Reputation-based Selection (ARS) for the edge-aided UAV network that utilizes blockchains to prevent single-point failures where we switched from central control to decentralized control, Interplanetary File System (IPFS) for off-chain model storage and their respective hash-keys on-chain to ensure model integrity. Due to IPFS, the size of the blockchain will be reduced, and local differential privacy will be applied to prevent privacy leakages. In the proposed framework, an aggregator will be selected based on its ARS score and model verification by the validators. After most validators approve it, it will be available for use. Several parameters are taken into consideration during evaluation, including accuracy, precision, recall, F1-score, and time consumption. It also evaluates the number of edge computers vs test accuracy, the number of edge computers vs time consumption for global model convergence, and the number of rounds vs test accuracy. This is done by considering two benchmark datasets: MNIST and CIFAR-10. The results show that the proposed work preserves privacy while achieving high accuracy. Moreover, it is scalable to accommodate many participants

TNN-IDS: Transformer neural network-based intrusion detection system for MQTT-enabled IoT Networks

The Internet of Things (IoT) is a global network that connects a large number of smart devices. MQTT is a de facto standard, lightweight, and reliable protocol for machine-to-machine communication, widely adopted in IoT networks. Various smart devices within these networks are employed to handle sensitive information. However, the scale and openness of IoT networks make them highly vulnerable to security breaches and attacks, such as eavesdropping, weak authentication, and malicious payloads. Hence, there is a need for advanced machine learning (ML) and deep learning (DL)-based intrusion detection systems (IDS). Existing ML-based IoT-IDSs face several limitations in effectively detecting malicious activities, mainly due to imbalanced training data. To address this, this study introduces a transformer neural network-based intrusion detection system (TNN-IDS) specifically designed for MQTT-enabled IoT networks. The proposed approach aims to enhance the detection of malicious activities within these networks. The TNN-IDS leverages the parallel processing capability of the Transformer Neural Network, which accelerates the learning process and results in improved detection of malicious attacks. To evaluate the performance of the proposed system, it was compared with various IDSs based on ML and DL approaches. The experimental results demonstrate that the proposed TNN-IDS outperforms other systems in terms of detecting malicious activity. The TNN-IDS achieved optimum accuracies reaching 99.9% in detecting malicious activities