Climate Change Impact in a Shallow Coastal Mediterranean Aquifer, at Saïdia, Morocco

A density dependent numerical flow model was applied to study the climate change impact in an unconfined shallow aquifer in the Mediterranean coast of Morocco. The stresses imposed to the model were derived from the IPCC emission scenarios and included recharge variations, rising sea level and advancing seashore. The simulations show that there will be a significant decline in the renewable freshwater resources and that salinity increases can be quite large but are limited to a restricted area

Optimization of the pentachlorophenol adsorption by organo-clays based on response surface methodology

The aim of this study is to optimize the adsorption of pentachlorophenol (PCP) using an organo-clay under the response surface methodology. The adsorbent was selected from a montmorillonite exchanged by various cations, such as Fe3+, Al3+, Zn2+, Mg2+, Na+ , and modified by bromide cetyltrimethylammonium (CTAB) as surfactant. The obtained organo-montmorillonite was characterized using several techniques, such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and nitrogen adsorption, performed at −196 ◦C. The results showed an increase in basal space from 1.65 to 1.88 nm and a decrease in the specific surface and pore volume, with an increase in pore diameter, including the presence of characteristic bands of -CH2 - and -CH3 - groups at 2926 and 2854 cm−1 in the FTIR spectrum after the modification. The optimization of PCP removal by clay adsorbents is achieved using the response surface methodology (RSM) with a four-factor central composite model, including pH of solution, mass of adsorbent, contact time, and initial concentration. The results proved the validity of the regression model, wherein the adsorption capacity reaches its maximum value of 38 mg/g at a lower adsorbent mass of 20 mg, pH of 6, contact time (tc) of 5 h, and initial concentration of 8 mg/L.S.E.M. thanks the Universidad Pública de Navarra for a doctoral grant. A.G. also thanks Banco Santander for funding through the Research Intensification Program

GSM-RF Channel Characterization Using a Wideband Subspace Sensing Mechanism for Cognitive Radio Networks

In this paper, we examine a spectrum sharing opportunities over the existing Global System of Mobile Communication (GSM) networks, by identifying the unused channels at a specific time and location. For this purpose, we propose a wideband spectrum sensing mechanism to analyze the status of 51 channels at once, belonging to the 10  MHz bandwidth centered at the frequency 945  MHz, in four different areas. We propose a subspace based spectral estimation mechanism, adapted to deal with real measurements. The process begins with data collection using Secondary User (SU) device enabled with Software Defined Radio (SDR) technology, configured to operate in the GSM band. Obtained samples are used then to feed the sensing mechanism. Spectral analysis is delivered to estimate power density peaks and corresponding frequencies. Decision making phase brings together power thresholding technique and GSM control channel decoding to identify idle and busy channels. Experiments are evaluated using detection and false alarm probabilities emulated via Receiver Operating Characteristic (ROC) curves. Obtained performances show better detection accuracy and robustness against variant noise/fading effects, when using our mechanism compared to Energy Detection (ED) based ones as Welch method, and Beamforming based ones as Minimum Variance Distortionless Response (MVDR) method. Occupancy results exhibit considerable potential of secondary use in GSM based primary network

Avancées des métaheuristiques pour l'optimisation combinatoire multi-objectif

Ce document présente certaines voies prometteuses, émergent actuellement dans le domaine de l'optimisation combinatoire multiobjectif. Résoudre de tels problèmes implique notamment la recherche d'un ensemble de solutions dites ``Pareto optimales''. Ces solutions sont les meilleurs compromis réalisable pour les différents objectifs à optimiser pour le problème étudié, le but étant de découvrir un ensemble de bonne qualité en terme de convergence, mais également en terme de diversité des compromis proposés. Dans le domaine des métaheuristiques, il existe plusieurs état de l'art du domaine traitant principalement des algorithmes évolutionnaires. Nous nous proposons ici d'enrichir ces études en relevant des approches récentes qui ont fait preuve d'innovation mais également de bons résultats. Aprés une introduction générale et avoir proposé une classification des méthodes usuelles, nous nous proposons de discuter des orientations récentes et prometteuses de la recherche dans ce domaine. Les approches étudiées sont l'application des métaheuristues mono-objectif récentes au cadre multi-objectif, les métaheuristiques hybrides, les métaheuristiques multi-objectif et le parallèlisme, et enfin l'optimisation multi-objectif sous incertitude. Nous concluerons par une discussion et quelques questions ouvertes

Acute flaccid paralysis incidence rate and epidemiology in children in Lebanon: a rise in numbers in the post-vaccination and refugee crisis era

Background: Acute flaccid paralysis (AFP) is a clinical syndrome characterized by the acute onset of weakness and paralysis with reduced muscle tone. This study explored the incidence and different aspects of AFP in Lebanese children between 2009 and 2019. Methods: AFP data were collected from the Lebanese Ministry of Public Health. Incidence rate according to year, age groups, clinical data, follow-up, diagnosis, and vaccination status was analyzed in the 11-years period. Results: AFP incidence rates increased importantly from 0.63 per 100,000 in 2009 till 4.96 per 100,000 in 2019. Most of the patients were children under ten years of age, 40.6% of all cases were under five years old, and 37.9% were between 5 and 9 years old. Follow-up revealed that approximately two out of five patients experienced residual weakness. As for the final diagnosis, around 30% of cases were diagnosed as Guillain-Barre Syndrome (GBS). Most cases were children having received between 3 and 5 doses of polio vaccine. Conclusions: The rise in cases coincided with the Syrian refugee crisis in Lebanon and the progressively deteriorating economy in the country; yet, incidence rates were in the lower margin compared with other countries. Keywords: Acute flaccid paralysis; Epidemiology; Guillain-Barré Syndrome; Lebanon; Pediatrics