Impact des lixiviats de la décharge sauvage de la ville de Taza sur les ressources hydriques (Maroc)

La population de Taza, estimée à environ 154 496 habitants, produit 18 000 tonnes par jour de déchet solide et ceci malgré la faible activité industrielle de cette région. Ces déchets sont essentiellement domestiques(0,85 kg/ jours/ habitant) et sont réacheminés vers la décharge publique de Taza. Cette dernière est installée sur une plaine alluviale s’étendant sur une superficie de 4 hectares et n’ayant bénéficié, ni d’une étude  préliminaire géologique ni hydrogéologique ni d’impact. De plus, le site de la décharge est à 1,2 Km du centre de l'agglomération et au coeur de l'Oued Larbâa ce qui pourrait générer de sérieux problèmes de pollution.L’objectif du présent travail est l’étude de la qualité des eaux superficielles et souterraines pour évaluer le degré de pollution provenant des lixiviats de la décharge et des cours d’eaux dans lesquels les rejets des eaux usées de la ville sont directement déversés. Les résultats obtenus, sur la base d’analyse des échantillons, ont montré une dégradation plus ou moins forte de la qualité physico-chimique des eaux de la nappe  souterraine et des eaux de surface spécialement en aval de la décharge et la présence d’une contamination bactérienne des eaux de surface et souterraines.Mots-clés : décharge sauvage, lixiviats, pollution, physico-chimie, Taza

Variability of a portion of RNA 3 containing the coat protein gene of Citrus variegation virus (CVV) using single-strand conformation polymorphism (SSCP)

A portion of RNA 3 of Citrus variegation virus (CVV), comprising part of the intergenic region and the coat protein (CP) gene from eight viral isolates, was amplified by RT-PCR and cloned. The clones were compared for intra and inter-isolate variations by single-strand conformation polymorphism analysis. Some of the results were compared with sequence data previously obtained. The test discriminated between clones differing in as little as 3.2% of the nucleotides. Most isolates included several variants, in some cases with a predominant pattern, which, however, could no longer be recognised in new RT-PCR products obtained 13 months later. This procedure can there-fore be used to identify and detect variations between CVV isolates. It is rapid, inexpensive and may reduce the amount of sequencing needed for comparing viral isolates

Genomic variability of Citrus tristeza virus (CTV) isolates introduced into Morocco

Genomic variability of the coat protein gene of Citrus tristeza virus isolates obtained from old Meyer lemon introductions in Morocco and more recent budwood introductions from Spain were studied. The coat protein gene of the virus was amplified directly from infected tissue by immunocapture RT-PCR and analysed by single stranded conformation polymorphism (SSCP) and sequencing. Each isolate consisted of several related genomic variants, typical of a quasi-species. Although SSCP analysis has only limited typing ability it could be used in an initial screening to discriminate between isolates of different origin and to analyse the genomic structure of each isolate. Sequence analysis showed that the isolates of Spanish origin were closely related to mild isolates characterised in Florida and in Portugal. The Meyer lemon isolate on the other hand was related to severe strains of Meyer lemon characterised in Florida some years ago and to other severe strains from Brasil. A knowledge of the coat protein gene sequence is useful to trace the origin of the isolates

IMPACT ANTHROPIQUE SUR LA QUALITE DES EAUX SOUTERRAINES DU BASSIN VERSANT DE L’OUED TAZA (MAROC) ANTHROPOGENIC IMPACT ON GROUNDWATER QUALITY IN THE WATERSHED OF OUED TAZA (MOROCCO)

The main objective of this work is to determine the status of the groundwater quality in the watershed of Taza river, based primarily on physico-chemical and bacteriological parameters of groundwater. The Oued Taza is a small mountain river, 13.44 Km long, which drains a watershed of 40.07 km ². The outlet located at an altitude of 420 m corresponds to the confluence with the Oued Iarbaa. The average annual rainfall varies between 352 mm and 719mm while the annual average temperature is 18.1 ° C. Very high concentrations of nitrates, nitrites, heavy metals and bacterial load in some points near urban areas, illustrate the effect of human activities on degradation of water quality. This contamination could have several causes, the most important are related to household and industrial discharges (especially waters) spilled without any treatment in the rivers, and the use of fertilizers in agricultural areas. These results will enrich the database on water quality in the basin, and help policy makers to better decide on the management of water resources for a better sustainable development of the regio

3D MODELS RETRIEVAL BASED ON TURNING ANGLE FUNCTION

Recent scanning technology and 3D modeling allowed having a large 3D meshes database. These models are widely used in several areas such as CAD, computer graphics and audiovisual production. Content based retrieval is a necessary solution to structure, to manage the multimedia data, and to navigate in these databases. In this paper, we propose a method to automatically search and retrieve 3D models visually similar to a query 3D model. This is based on the representation of a 3D model by a series of slices along a direction; the nearest models to the query are those which have cuts similar to it

Citrus variegation virus: Molecular variability of a portion of the RNA 3 containing the coat protein gene and design of primers for RT-PCR detection

The coat protein gene and part of the intergenic region of the RNA 3 of several isolates of Citrus variegation virus (CVV) producing either infectious variegation or crinkly leaf symptoms were amplified by RT-PCR, cloned and sequenced. Some isolates were composed of a mixture of sequence variants. The coat protein gene appeared to be highly conserved (lowest similarity among all CVV sequences 93%), especially at the N-terminal, indicating at the molecular level that both types of symptoms are indeed produced by the same virus species. No relationship could be found with the geographic origin. Sequences obtained from isolates producing infectious variegation clustered in a different branch of a dendrogram than those originating from crinkly leaf symptoms. Both clusters could further be distinguished by two parsimonious sites in the coat protein gene. In the short stretch of the intergenic RNA 3 region analysed, a stable hairpin exists in addition to the previously reported hairpin that constitutes the core promoter for the RNA 4 transcription. This second hairpin could also be recognised in the other subgroup 2 Ilarviruses. Surprisingly, at the nucleotide and amino acid levels and in the secondary features of the intergenic region, CVV appeared closer to the other subgroup 2 Ilarviruses than to Citrus leaf rugose virus to which it is serologically related and has been considered to be evolutionary related. Using primers designed for the conserved regions, the virus was detected with a prevalence of 25% and 13% in Portuguese and Moroccan citrus collections. A group of RT-PCR positives was further confirmed by ELISA and biological indexing