University of Bechar

Abstract Urban sprawl today constitutes one of the main factors driving landscape transformation in developing countries. This process promotes the fragmentation of natural environments, the disruption of ecological continuities, and the weakening of essential environmental functions, thereby contributing to the gradual degradation of quality of life in urban areas. In Tlemcen, Algeria, this dynamic is particularly noticeable, especially regarding green spaces, which play a decisive role in maintaining ecological balance and regulating local environmental conditions, making a precise ecological assessment of the most sensitive sites necessary. In this context, the present study aims to establish an in-depth ecological diagnosis of the example of the Jardin du Grand Bassin, a historic site representative of Tlemcen’s urban landscape, in order to evaluate its level of fragmentation, floristic composition, vegetation structure, and overall ecological condition. The methodological approach adopted is based on a comprehensive strategy combining several complementary tools. Spatial analysis using GIS allows for the examination of landscape configuration, the identification of fragmented areas, and the detection of still-functional ecological corridors, essential elements for understanding intraurban ecological dynamics. The Forest Development Type method is employed to describe vegetation stratification, characterize formation types, and identify dominant landscape structures, while a detailed floristic inventory, developed through extensive bibliographic research, organizes species according to their strata and canopies in order to apprehend the site’s plant diversity. Finally, the calculation of an ecological perturbation index (IP) complements the assessment by providing a quantitative measure of the level of environmental pressure. The results reveal that despite the presence of highly fragmented zones, several ecological corridors remain active, opening possibilities for targeted priority actions in ecological restoration. The site presents a notable floristic richness of 106 species, and the ecological perturbation index reaches 31.13%, reflecting a moderately stable ecosystem but subjected to real pressures. Analyses derived from the method show an organization of vegetation strata reflecting an exogenous horticultural heritage, characteristic of the Grand Bassin and determinant for its ecological functioning. By providing an in-depth ecological diagnosis of a major urban green space, this study fills a gap in scientific knowledge regarding the ecological condition of urban green spaces in Tlemcen and constitutes a valuable tool for urban managers. It proposes strategic orientations for sustainable management, urban biodiversity preservation, and the strengthening of ecological connectivity, positioning the Jardin du Grand Bassin as a reference model for environmental restoration initiatives and long-term ecological planning.

The hypersaline and alkaline sebkhas of Adrar (Algeria) constitute extreme ecosystems that have remained largely unexplored. The objective was to isolate and to characterize various Bacillus strains extracted from these specific environments. Two polyextremophilic isolates, Bacillus tequilensis (KM9) and Bacillus paralicheniformis (KM2), were identified through the analysis of 16S rRNA phylogeny. Physiological testing demonstrated robust adaptations: Isolate KM9 exhibited a broad salinity range (ranging from 2 to 17.0% w/v NaCl, Sopt 6%) and strict alkaliphily (pHoptimum 9.5, with growth observed up to pH 11.0). In contrast, Isolate KM2 exhibited higher thermal tolerance (Tmaximum 50 degrees C, Toptimum 40 degrees C), while maintaining growth up to 20% NaCl and pH 10.5. Functional profiling via API ZYM (Analytical Profile Index ZYM) revealed Isolate KM9's N-acetyl-beta-glucosaminidase activity, whereas Isolate KM2 demonstrated a broad hydrolytic spectrum (including proteases and glycosidases) and potent antimicrobial efficacy against Staphylococcus aureus (25 mm), Pseudomonas aeruginosa (20 mm), as well as showing 50% inhibition of Fusarium oxysporum and Aspergillus flavus. These findings underscore the Adrar sebkhas as untapped reservoirs for diverse Bacillus strains. Their ability to remain active under simultaneous thermal, saline, and alkaline stress underscores their potential as sources of robust extremozymes and biocontrol agents for industrial biotechnology.

The q-Weibull distribution is a flexible probability distribution that is commonly used in reliability analysis, survival analysis, and extreme value modelling. Obtaining accurate parameter estimates is essential for these applications. This paper investigates several estimation techniques for the q-Weibull distribution, with special emphasis on the Metropolis-Hastings algorithm. Through an extensive simulation study, we evaluate the performance of these methods across different sample sizes. In addition, we apply them to a real dataset to illustrate their practical utility and to highlight situations where the Metropolis-Hastings approach proves particularly advantageous.

Lifetime data arising in engineering reliability, survival analysis, actuarial science, and environmental studies often exhibit substantial right-skewness, extreme observations, and heterogeneous hazard-rate structures. Classical lifetime distributions may not adequately capture these characteristics, thereby affecting risk assessment, reliability evaluation, and predictive performance. In this paper, we introduce the Heavy-Tailed QLindley (HTQL) distribution, a new two-parameter heavy-tailed extension of the QLindley model obtained through the New Family of Heavy-Tailed (NFHT) transformation. The proposed distribution provides greater flexibility for modelling positively skewed and heavy-tailed data while preserving analytical tractability. The HTQL model accommodates increasing, decreasing, bathtub-shaped, unimodal, and nearly constant hazard rate functions, making it suitable for applications in reliability analysis, survival studies, actuarial science, and environmental modelling. Several mathematical and statistical properties of the HTQL distribution are derived, including explicit expressions for the quantile function, ordinary and incomplete moments, order statistics, and reliability measures. Important tail-based risk measures such as Value-at-Risk, Tail Value-at-Risk, Tail Variance, Tail Variance Premium, and Expected Shortfall are also obtained. Parameter estimation is investigated using maximum likelihood, ordinary least squares, Cram & eacute;r-von Mises, and Bayesian approaches, together with bootstrap confidence intervals. A Monte Carlo simulation study is conducted to evaluate the finite-sample performance of the proposed estimators. The practical usefulness of the HTQL distribution is illustrated using three real-world datasets from pharmacokinetics, engineering reliability, and environmental studies. The empirical results show that the HTQL distribution provides highly competitive fits compared with several classical, Lindley-type, and heavy-tailed distributions. Overall, the proposed model constitutes a flexible and parsimonious alternative for modelling positive heavy-tailed data.

The purpose of this research is to examine the dynamic performance of a squirrel cage induction generator (SCIG)-based wind turbine connected to the power grid. It focuses on managing voltage instability resulting from the reactive power demand inherent in SCIG along with various grid disturbances. Three compensation strategies were designed, compared, and studied, including no compensation system, a system with fixed capacitor bank, and a system using a Static Synchronous Compensator (STATCOM). The model is subjected to different perturbations, including wind speed changes, a sudden load application, and both symmetrical and asymmetrical fault scenarios. The results indicate that, although the fixed capacitor bank provides enhanced reactive power support when the system is at the single pre-set operating point, it is unable to respond effectively to rapid system changes, causing significant voltage sags as well as overcompensation. On the other hand, the STATCOM effectively maintains the point of common coupling (PCC) voltage close to the reference of 1.0 pu by continuously injecting or absorbing reactive power. The ability of STATCOM to support low-voltage ride-through (LVRT) demonstrates its superior performance and suitability for enhancing wind energy grid integration.