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In recent years, there has been a growing replacement of synthetic fibers by natural ones, particularly by autochthonous materials. In the case of Algeria, the most abundant plant resources are the PALF (Pineapple leaf fiber), the date palm, and the Alfa fibers. In this work, the development and use of analytical and numerical methods are proposed to predict the mechanical properties of layers based on natural fibers that will be applied to manufacture skins of the sandwich cylinder. To achieve these predictions, four analytical models were used, namely the Halpin–Tsai, the Chamis, the Hashin vs. Rosen, and the ROM. The analytical results were compared with the numerical simulations and experimental data. The prediction of the elastic properties of the three fiber-based eco-composites showed an important dispersion in terms of stiffness.

Major depressed individuals are a subpopulation at high-risk of suicide. However, despite the evidence for a particular relationship between suicidal ideation (SI) and type D personality, few studies have investigated the role played by this personality structure in the occurrence of SI in major depressed individuals. Data from 318 major depressed individuals recruited from the clinical database of the Sleep Laboratory were analysed. Suicidal ideation was considered present if the score in item 9 of the Beck Depression Inventory (BDI-II) was ≥1 and/or if they were highlighted during the systematic psychiatric assessment conducted on admission to the Sleep Laboratory. Logistic regression analyses were used to determine the risk of SI associated with type D personality in major depressed individuals. The prevalence of suicidal ideation was 38.4% in our sample of major depressed individuals. After adjusting for major confounding factors, multivariate logistic regression analyses demonstrated that type D personality was a risk factor for SI in major depressed individuals. Thus, given the potential role played by type D personality in the occurrence of SI in major depressed individuals, it seems necessary to more systematically research and adequately manage this personality structure to allow for a better prevention of suicidal behaviours in this subpopulation.