Development of mathematical models for predicting the iron concentrations of Lake Oubeira waters (ne Algerian)

Facing the increase of surface water samples contaminated by ETMs, usually from the geochemical background, the emergence of new human diseases is worrying. To solve this problem, we have developed several models based on different learning algorithms qualified by high performance, using different transfer functions. We have shown that all the Neural Models presented more or less important performance  compared to the one based on multiple linear regressions. The best revealed model ANN in the current work is a MLP type that uses the Levenberg-Marquardt algorithm as a learning algorithm, with Tansig and Purelin as transfer functions, respectively in the hidden layer and the output layer. This successful model can be considered as an important tool of great effectiveness in the context of environmental prediction and especially in anticipation of the iron contents of the Oubeira Lake water.Keywords: Prediction, heavy metals, Linear multiple regression, artificial neural  networks, Oubéira Lake

Plant growth promoting activities of Pseudomonas sp. and Enterobacter sp. isolated from the rhizosphere of Vachellia gummifera in Morocco

The Moroccan endemic Vachellia gummifera grows wild under extreme desert conditions. This plant could be used as an alternative fodder for goats, and camels, in order to protect the Argan forests against overgrazing in Central and Southwestern Moroccan semiarid areas. With the aim to improve the V. gummifera population's density in semiarid areas, we proposed its inoculation with performing plant growth-promoting bacteria. Hence, 500 bacteria were isolated from the plant rhizosphere. From these, 291 isolates were retained for plant growth-promoting (PGP) activities assessment. A total of 44 isolates showed the best phosphates solubilization potential, as well as siderophore and auxin production. The combination of REP-PCR (repetitive extragenic palindromic-polymerase chain reaction) fingerprinting, PGP activities, and phenotypic properties, allowed the selection of three strains for the inoculation experiments. The three selected strains' 16S rRNA sequencing showed that they are members of the Enterobacter and Pseudomonas genera. The inoculation with three strains had diverse effects on V. gummifera growth parameters. All single and combined inoculations improved the plant shoot weight by more than 200%, and the root length by up to 139%, while some combinations further improved protein and chlorophyll content, thereby improving the plant's forage value. The three selected strains constitute an effective inoculum for use in the arid and semiarid zones of southern Morocco.The authors want to thank all the persons who contributed to the achievement of this work. This work was funded by the Hassan II Academy of Science and Technology (AH2ST), in Morocco. B.M. received a grant from the AH2ST. She received also the excellency fellowship Khadija Baddouri in life sciences, from the Horizons foundation, Franc

Signal patterns of piston slap of a four-cylinder diesel engine

This paper presents an experimental study on the vibration signal patterns associated with a simulated piston slap test of a four-cylinder diesel engine. It is found that a simulated worn-off piston results in an increase in vibration RMS peak amplitudes associated with the major mechanical events of the corresponding cylinder (i.e., inlet and exhaust valve closing and combustion of Cylinder 1). This then led to an increase of overall vibration amplitude of the time domain statistical features such as RMS, Crest Factor, Skewness and Kurtosis in all loading conditions. The simulated worn-off piston not only increased the impact amplitude of piston slap during the engine combustion, it also produced a distinct impulse response during the air induction stroke of the cylinder attributing to an increase of lateral impact force as a result of piston reciprocating motion and the increased clearance between the worn-off piston and the cylinder. The unique signal patterns of piston slap disclosed in this paper can be utilized to assist in the development of condition monitoring tools for automated diagnosis of similar diesel engine faults in practical applications

Assessment of Pollution in Sidi M'Hamed Benali Lake (Algeria) Based on Bioindicators and Physicochemical Parameters

peer reviewedThis study was carried out to investigate the degree, the nature and the origin of pollution in Sidi M’hamed Benali Lake using the physicochemical parameters, saprobic index and cladocerans. For this purpose, water and zooplankton sampling was collected from six sites in lake during five seasons. The average seasonal values of physicochemical parameters showed that the lake undergoes a slight anthropogenic and natural pollution in the dry and wet periods. Presence of certain toxic substances (CN-, Cr, Ni) require us to be more careful in irrigation, bathe and the consumption of fishes of that reservoir. Overall, oligo-mesosaprobic to beta-mesosaprobic rotifers have been prevailing in all five seasons indicating that the water was slightly or moderate polluted. The presence of Bosmina longirostris, Daphnia longispina, Daphnia cuculata, Daphnia ambiga and Sididae diaphonosoma brachyrum indicate bacterial contamination with the intense development of the phytoplankton in the lake, especially in springs and summer. Pearson correlation analysis revealed significant correlation between all of the physicochemical parameters. However, it revealed no significant correlation between zooplanktons occurrence and the majority environmental variables values. In present investigation, the Lake water is relatively little exposed to pollution and does not undergo strong organic pollution

Sélection de quelques plantes médicinales du Zerhoun (Maroc centrale) pour l’activité antibactérienne contre Pseudomonas aeruginosa

Objective: To evaluate the in vitro antibacterial activities of two extracts (Aqueous extract and ethanolic extract) from the leaves of fourteen medicinal plants found in Zerhoun (central Morocco) on the growth of six strains of Pseudomonas aeruginosa. Methodology and Results: The method of diffusion in solid and macromethod of dilution in liquid medium from active extract were used for antibacterial testing. The results showed that aqueous extracts were more active than the ethanol extracts. The plant extracts were more active against pigmented strains (pyocyanin) than against non-pigmented strains. Eight plants showed antibacterial activity against one or more bacterial strains. The aqueous extract of Eucalyptus gomphocephala presented the highest anti Pseudomonas aeruginosa activity against all strains tested with zones of inhibition between 16 and 18.5 mm, having an MIC value (6.25-12. 5mg/ml) and MBC (6.25-25mg/ml). Conclusion and Application: According to this study results, water was the best solvent in the concentration of the active ingredients of the plants. In addition, the antibacterial activities of the extracts from the leaves of eucalyptus in this study could justify the therapeutic use of this plant in traditional medicine in the treatment of many bacterial infections.Keywords: antibacterial activity; aqueous extracts; ethanol extracts; Pseudomonas aeruginosa; eucalyptus gomphocephala

Parasitoses opportunistes digestives chez les adultes infectés par le VIH : Aspects épidémiologiques Opportunistic digestive parasitic infections in adults infected with HIV: epidemiological expression

Introduction :Les parasitoses digestives opportunistes restent les principaux agents responsables de diarrhées chez les patients infectés par le VIH/Sida. Ce sont des infections classant Sida.le but de travail était de déterminer  la fréquence des parasitoses digestives opportunistes chez les patients infectés par le VIHMatériels et méthodes :Etude retroprospective descriptive de 20 mois déroulée dans le service de maladies infectieuses de casablanca. Ont  été inclus tous les patients infectés par le VIH et présentant une parasitose digestive opportuniste confirmée à l’EPS.Résultats :Nous avons colligé 70 patients.  L’âge moyen était de 37 ans. La médiane de lymphocytes CD4 était de 62celellule/mm³. Les parasitoses opportunistes digestives étaient révélatrices de l’infection à VIH dans 54 cas (77%)  et dans 16 cas (23%) elles sont survenues au décours d’un échec thérapeutique. Tous les patients présentaient des diarrhées liquidiennes. Ces agents parasitaires opportunistes étaient isolés seuls dans 56 cas dont 28 cas de Cryptosporidiose (40%),  22 cas de microsporidiose (31%), 4 cas d’Isospora belli (6%) et 2 cas de cyclosporose (3%).  Elles étaient associées dans 14 cas dont 13 cas de Cryptosporidiose + Microsporidiose (18,57%) et 1 cas de Cryptosporidiose + Isosporose (1,43%).  Sous HARRT, 86% des patients ont bien évolué (n=60) et nous avons enregistré 14% de décès (n=10).Conclusion :Les parasitoses digestives opportunistes restent fréquentes dans notre contexte à cause du diagnostic tardif  du VIH/SIDA. Le dépistage précoce du VIH permettra de les prévenir