217 research outputs found

    News Sites and Fake News in the Egyptian Political Transformation 2013–2014: Aljazeera.net case study

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     Online activities allow users to benefit from, and engage with, news and information in a more complex way than was possible with old news settings. However, many have expressed concerns about the effects of false news stories, or ‘fake news’, circulated largely via online services on public view. This study examines the news sites’ behaviour and the attitudes of elite Egyptian academics towards information provided by the aljazeera.net news site during the Egyptian political conflict and the transformation from former President Mohamed Morsi to current President Abdul Fatah el-Sisi. A total of 450 elite academics were surveyed online to evaluate news and information about the political conflict and the transformation in Egypt through focusing on how they became informed about such news, their perceptions of news via the aljazeera.net site and their evaluation of whether the network has misused information regarding this period. The results indicated that the aljazeera.net site used different, false and ‘fake news’ techniques mainly in support of the pro-Morsi position during the transition to el-Sisi. Respondents indicated that misinformation was clearly provided by aljazeera.net in different formats, though some highlighted the importance of accessing news from online sources. Respondents indicated that online content can be easily spread among users with no significant third-party filtering, fact checking or editorial judgment. This raises questions about who becomes the arbiter of truth.     Keywords: Fake News, Misinformation News, Online News Sites, aljazeera.net, Mohamed Morsi, Abdul Fatah el-Sisi, News Propaganda, Social Networking Sites, Online Audience

    A Stable Integrated Photoelectrochemical Reactor for H₂ Production from Water Attains a Solar‐to‐Hydrogen Efficiency of 18 % at 15 Suns and 13 % at 207 Suns

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    The major challenge in solar water splitting to H_{2} and O_{2} is in making a stable and affordable system for large‐scale applications. We have designed, fabricated, and tested a photoelectrochemical reactor characterized as follows: 1) it comprises an integrated device to reduce the balance of the system cost, 2) it utilizes concentrated sunlight to reduce the photoabsorber cost, and 3) it employs and alkaline electrolyte to reduce catalyst cost and eliminate external thermal management needs. The system consists of an III‐V‐based photovoltaic cell integrated with Ni foil as an O_{2} evolution catalyst that also protects the cell from corrosion. At low light concentration, without the use of optical lenses, the solar‐to‐hydrogen (STH) efficiency was 18.3 %, while at high light concentration (up to 207 suns) with the use of optical lenses, the STH efficiency was 13 %. Catalytic tests conducted for over 100 hours at 100–200 suns showed no sign of degradation nor deviation from product stoichiometry (H_{2}/O_{2}=2). Further tests projected a system stability of years

    Numerical simulation of rare earth ions clustering in silica by ion implantation

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    Date du colloque : 03/2010International audienc

    Prediction by a Genetic Algorithm of the Fiber-Matrix Interface Damage for Composite Material. Part 2. Study of Shear Damage in Graphite/Epoxv Nanocomposites

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    The objective in this paper is to apply the same genetic model as applied in Part 1 to optimizing the shear damage to the fiber–matrix interface of nanocomposite material graphite epoxy. The results show good agreement between the numerical simulation and the actual behavior of the material chosen composite and nanocomposites, and these results are similar to results obtained by processing techniques expanded graphite reinforced polymer nanocomposites made by Asma Yasmine. These results were confirmed by calculating the rate of damage with a genetic simulation.Описанная в сообщении 1 генетическая модель используется для оптимизации повреждения в плоскости максимальных сдвиговых напряжений на стыке волокон и матрицы в нанокомпозитном графито-эпоксидном материале. Получена хорошая корреляция между численными расчетами и экспериментальными данными для композита и нанокомпозитов на основе графита, усиленного нанополимерами. Экспериментальные данные также хорошо согласуются с результатами, полученными на основании расчетной методики Ясмина. В дальнейших исследованиях планируется изучение влияния термических напряжений на подобную оптимизацию.Описана в повідомленні 1 генетична модель використовується для оптимізації пошкодження в площині максимальних зсувних напружень на стику волокон і матриці в нанокомпозитному графіто-епоксидному матеріалі. Отримано хорошу кореляцію між числовими розрахунками й експериментальними даними для композита та нанокомпозит ів на основі графіту, підсиленого нанополімерами. Експериментальні дані також добре узгоджуються з результатами, що отримані на основі розрахункової методики Ясміна. У подальших дослідженнях планується вивчення впливу термічних напружень на подібну оптимізацію

    Caractérisation physique du bois de la loupe de Thuya

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    International audienceCe travail constitue une contribution originale à l'étude de la densité et du retrait au séchage de la loupe de thuya provenant de la forêt de Khémisset (Maroc). La densité est souvent utilisée dans les étapes de prédiction des propriétés mécaniques du bois. Quant aux retraits linéaires, l'existence ou non d'une anisotropie entre les retraits radial, tangentiel et longitudinal préfigurent du comportement mécanique du bois. Les mesures de ces propriétés physiques sont réalisées sur 77 échantillons de 2×2×2cm3 découpés selon les directions radiale, tangentielle et longitudinale. L'analyse des résultats des mesures de densité permet de classer le bois de la loupe de thuya comme un bois dense. La densité de la loupe est plus élevée que celle du bois de thuya. Cette différence s'explique par la présence d'excroissances foncées composées de cellules aux parois plus épaisses que celles du bois de thuya. L'analyse des mesures de retraits montre une faible anisotropie de retraits, expliquée à l'échelle microscopique dans un plan de référence, par une orientation très variable des cellules. Ce résultat présuppose un comportement mécanique proche d'un comportement isotrope du bois de la loupe de thuya

    Profiling polyphenol composition by HPLC-DAD-ESI/MSn and the antibacterial activity of infusion preparations obtained from four medicinal plants

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    The infusions of Thymus pallescens Noë, Saccocalyx satureioides Coss. et Dur., Ptychotis verticillata Briq. and Limoniastrum guyonianum Boiss. have been used as medicinal remedies for many diseases in Algerian folk medicine. These species have also been well documented as rich sources of phytochemicals, such as phenolic compounds with wide diversified chemical structures, which exhibit far-ranging biological activities. Thus, the phenolic compound profile of the aqueous extracts, obtained by infusing, of the mentioned species was obtained by HPLC-DAD-ESI/MS, and their antibacterial activity was evaluated against clinical isolates. Several phenolic acids were identified and quantified, particularly caffeic acid derivatives along with glycosylated flavonoids. T. pallescens and S. satureioides contain 13 phenolic compounds, where rosmarinic acid was the most abundant phenolic acid present, while L. guyonianum presented myricetin-3-O-glucoside and myricetin-O-rhamnoside as the main compounds among the eight detected molecules. P. verticillata presented a profile of ten phenolic compounds, where 5-O-caffeoylquinic acid was the most abundant phenolic acid, followed by the flavone luteolin-3-O-glucoside. The antibacterial activity of the infusions ranged between 2.5 and 20 mg mL−1 (MIC values), and L. guyonianum showed the highest activity against all of the tested bacteria, Staphylococcus aureus and Pseudomonas aeruginosa being the most sensitive and resistant strains, respectively. Thus, the studied plant species are sources of natural antibacterial substances that can be used to fight against pathogenic microorganisms.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), S. Heleno (SFRH/BPD/101413/2014) grant and L. Barros contract. The authors are also grateful to the Interreg España- Portugal for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio

    Phenolic compounds characterization by LC-DAD- ESI/MSn and bioactive properties of Thymus algeriensis Boiss. & Reut. and Ephedra alata Decne

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    Scientific research has been focused on finding natural occurring molecules from plant origin. Herein, infusion, decoction and hydroethanolic extracts of Thymus algeriensis Boiss. & Reut. and Ephedra alata Decne. from Algeria were phytochemically characterized by LC-DAD-ESI-MSn, and evaluated regarding bioactive properties (antioxidant and antibacterial). Flavonol and flavone glycoside derivatives and phenolic acids, specially rosmarinic acid and kaempferol-O-glucuronide were the major compounds in T. algeriensis extracts. Otherwise, E. alata presented isoflavones and flavonol derivatives as main compounds, being hydroxypuerarin isomer 1 the major molecule. Aqueous extracts had significantly higher antioxidant activity, being this activity correlated with the amount of phenolic compounds. Antimicrobial activity of the extracts was tested against multi-resistant bacteria strains from clinical isolates. The obtained MIC values indicate that the hydroethanolic extracts revealed the highest effect, especially the one of T. algeriensis against Gram-positive bacteria. Hence, these plant extracts could be used in the development of bioactive ingredients.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), S. Heleno grant (SFRH/BPD/101413/2014) and L. Barros contract. The authors are also grateful to the Interreg España-Portugal for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio
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