213 research outputs found

    A new species of the genus Alainites Waltz & McCafferty, 1994 (Ephemeroptera, Baetidae) from the north of Morocco.

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    A new species of Alainites is described from northern of Morocco Alainitesalbaisp. nov. It can be separated from the other west Palearctic species by the gill number, the spination of the distal margin of tergites, the leg setation, and the paraproct shape and spination. This species is widespread in the study area but never abundant. It prefers small to medium streams with slow flow, and does not seem to be very sensitive to pollution and water logging activities

    Another new species of the genus Habrophlebia Eaton, 1881 (Ephemeroptera, Leptophlebiidae) from the Maghreb.

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    A new species belonging to the genus Habrophlebia Eaton, 1881 is described at the nymphal stage from the Rif Mountains of Morocco. This species presents unique features, such as the chorionic arrangement of the egg and the ornamentation of the posterior margin of abdominal tergites. It is compared to all west European Habrophlebia species and a table with discriminating characters is given. A phylogenetic reconstruction based on COI sequences fully supports the hypothesis of a new species in the Rif Mountains, with possible further distribution in southern Spain

    Two new species of Centroptilum Eaton, 1869 from North Africa (Ephemeroptera, Baetidae).

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    Based on recently collected larvae from Algeria and Morocco, the species delimitation within the genus Centroptilum Eaton, 1869 in that region is validated. Two new species are described and illustrated, one from north-eastern Algeria, and one from North Morocco, using an integrated approach with morphological and molecular evidence. A table summarising the morphological differences between the new species and Centroptilumluteolum (Müller, 1776) from Central Europe is provided. Further, molecular evidence for additional undescribed species of Centroptilum in other regions of the West Palearctic is provided and discussed

    Design and optimization of a new compact 2.4 GHz-bandpass filter using DGS technique and U-shaped resonators for WLAN applications

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    The objective of this work is the study, the design and the optimization of an innovative structure of a network of coupled copper metal lines deposited on the upper surface of a R04003 type substrate of height 0.813 with a ground deformed by slots (DGS). This structure is designed in an optimal configuration for use in the design of narrowband bandpass filter for wireless communication systems (WLAN), the aim of use the defected ground structure is to remove the unwanted harmonics in the rejection band, the simulation results obtained from this structure using CST software show a very high selectivity of the designed filter, a very low level of losses (less than-0.45 dB) with a size overall size of 43.5x34.3 mm

    Fracture energy of wood and root burl wood of thuya (Tetraclinis articulata (Vahl) Masters)

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    International audienceThe fracture energy of wood and root burl wood of thuya, coming from the forest of Essaouira (Morocco), was measured using a single edge notched specimen bending (SENB) test method. The variations along the longitudinal and transverse directions were studied using specimens taken from one radial section of thuya wood and on radial section of thuya burl, originating from two different trees. Thuya burl was more resistant than thuya wood to crack propagation in RL system (in the tangential plane). This difference is explained by the presence of dark growths, composed of cells with thicker walls that make the burl wood usually denser than thuya wood. Thuya burl was more resistant to crack propagation in RL system (tangential plane) than in TL system (radial plane), which is consistent with the radial orientation of the dark growths. The observed decrease of fracture energy along the longitudinal direction was explained by the progressive reduction of dark growth concentration

    Tuberculous Duodenal Stenosis: Report of Two Cases

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    Duodenal tuberculosis is a rare clinical entity. The authors report and emphasize the lack of special clinical, radiological and endoscopic signs of duodenal tuberculosis. The diagnosis is affirmed, at laparotomy, out of the findings of peritoneal granulations or histology of lymphatic nodes. We report our experience of two cases of duodenal tuberculosis presenting with proximal intestinal obstruction and review the available literature

    Comparative Biology and Life Cycle of The Barley Stem Gall Midge and Hessian fly (Diptera: Cecidomyiidae) in Morocco

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    The barley stem gall midge, Mayetiola hordei (Keiffer) is the most serious pest of barley in Morocco. The biology and life cycle of this insect were studied in a laboratory and under natural weather conditions. The results showed that similarly to Hessian fly, barley stem gall midge has two feeding instars and a third non-feeding instar. The generation time was longer for barley stem gall midge than for Hessian fly (45 vs 32 days at 18 ± 1°C, and a 12:12 (L: D) h photoperiod). The eggs of barley stem gall midge hatched in 7 days compared to 4 days for Hessian fly. The largest discrepancy in developmental time was for second instar and pupa. Second instars and pupae of barley stem gall midge required twice as long as those of Hessian fly to develop and molt into next stage (12 vs. 6 days). The first and third instars of barley stem gall midge also required a little bit longer to complete development (9 and 10 days vs. 7 and 8 days for Hessian fly). Like for Hessian fly, barley stem gall midge reproduces mostly by unisexual progenies. Four progeny classes were observed; unisexual female progenies, unisexual male progenies, predominantly female progenies, and predominantly male progenies. The proportion of unisexual female and male progenies and the proportion of predominantly female and predominantly male progenies were similar. Overall, the sex ratio of both species was about 1:1. Under field weather conditions that prevail in the Chaouia region of Morocco, barley stem gall midge has two complete generations and a third partial one. The first generation starts late October, and ends late December. The second generation develops from January until early March. A high proportion of third instars of this generation fail to pupate (35%). The third generation is only partial; adults of the second generation emerge during March, oviposit and larvae develop to third instars but all go into summer diapause.

    The endemic Chamaecytisus albidus is nodulated by symbiovar genistearum of Bradyrhizobium in the Moroccan Maamora Forest

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    Out of 54 isolates from root nodules of the Moroccan-endemic Chamaecytisus albidus plants growing in soils from the Maamora cork oak forest, 44 isolates formed nodules when used to infect their original host plant. A phenotypic analysis showed the metabolic diversity of the strains that used different carbohydrates and amino acids as sole carbon and nitrogen sources. The isolates grew on media with pH values ranging from 6 to 8. However, they did not tolerate high temperatures or drought and they did not grow on media with salt concentrations higher than 85 mM. REP-PCR fingerprinting grouped the strains into 12 clusters, of which representative strains were selected for ARDRA and rrs analyses. The rrs gene sequence analysis indicated that all 12 strains were members of the genus Bradyrhizobium and their phylogeny showed that they were grouped into two different clusters. Two strains from each group were selected for multilocus sequence analysis (MLSA) using atpD, recA, gyrB and glnII housekeeping genes. The inferred phylogenetic trees confirmed that the strains clustered into two divergent clusters. Strains CM55 and CM57 were affiliated to the B. canariense/B. lupini group, whereas strains CM61 and CM64 were regrouped within the B. cytisi/B. rifense lineage. The analysis of the nodC symbiotic gene affiliated the strains to the symbiovar genistearum. The strains were also able to nodulate Retama monosperma, Lupinus luteus and Cytisus monspessulanus, but not Phaseolus vulgaris or Glycine max. Inoculation tests with C. albidus showed that some strains could be exploited as efficient inocula that could be used to improve plant growth in the Maamora forest.The authors want to thank all the people who contributed to theachievement of this study. Financial support was obtained from‘‘Académie Hassan II des Sciences et Techniques” (Morocco). MrOmar Bouhnik received a grant from the Hassan II Academy of Science and Technology. The authors also thank the Ministerio de Economía, Industria y Competitividad (Spain) for the granting ofthe ERDF-cofinanced project AGL2017–85676R

    Numerical Study of the Bond Strength Evolution of Corroded Reinforcement in Concrete in Pull‐Out Tests

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    The corrosion of rebars in reinforced concrete structures impacts their geometry (diameter and ribs) and mass, damages the concrete at the interface between the two materials, deteriorates the bond strength, and causes the cracking of the concrete cover. In the following study, a 2D numerical model of the pull‐out test is presented in order to study the impact of corrosion on the bond strength. Several parameters are investigated: the embedment depth, the rebar’s diameter, and the width of the concrete cover. The model reproduces the slip of the rebar and the failure through the splitting of concrete. It integrates an interface between the two materials and a concrete damage model that simulate the deterioration of concrete in compression and tension. The results obtained are validated with experimental data from the literature. Moreover, a parametric study is carried out to determine the impact of the embedment depth, the diameter of the rebar, and the concrete cover on the bond strength. The present study confirms that a greater embedment depth increases the pulling load. The study also confirms that the rebar’s diameter impacts highly the loss of bond between the rebar and the concrete cover. Lastly, the final main result of this paper is that the width of the concrete cover slows the loss of bond strength between the two materials
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