Comment un copépode bioindicateur (ou cosmopolite) varie-t-il dans des réservoirs de qualité trophique différente ? Un cas en Algérie

Les effets de paramètres physicochimiques sur la dynamique d’Acanthocyclops robustus dans quatre réservoirs (Kedarra, Gargar, Cheurfas II et Ghrib) situés dans les régions de l’ouest et du centre de l’Algérie ont été étudiés. Des échantillons d’eau ont été prélevés saisonnièrement le long d’une année. Les densités d’A. robustus n’étaient pas stables au cours de l’année ; elles dépendaient des variations des facteurs environnementaux. Des tests statistiques ont été utilisés pour démontrer les interactions entre les paramètres environnementaux et la densité d’A. robustus. Il y avait une hétérogénéité dans les paramètres physico-chimiques mesurés selon les réservoirs. L’indice de pollution organique des eaux du réservoir variait entre 2,5 (forte pollution organique) et 3,75 (pollution organique modérée). Acanthocyclops robustus est une espèce pérenne dans les quatre réservoirs. La densité de l’espèce variait selon l’échelle spatio-temporelle ; la densité la plus élevée a été observée à Kedarra (317,542 ind./L) et la plus faible a été trouvée dans le réservoir de Cheurfas II (41,692 ind./L). Les résultats ont montré que l’espèce était très sensible à l’eutrophisation ; sa densité était corrélée positivement avec la transparence et l’indice de pollution organique, mais négativement avec la conductivité, le calcium, les matières en suspension, NH4 et DBO5.The effects of physicochemical parameters on the dynamics of Acanthocyclops robustus in four reservoirs (Kedarra, Gargar, Cheurfas II, and Ghrib) located in the western and central regions of Algeria were studied. Water samples were taken seasonally along a year. The densities of A. robustus were not stable during the year; they depended on variations in the environmental factors such as the transparency of water, orthophosphates, conductivity, BOD5, and nutrients. Statistical tests were used to demonstrate the interactions between the environmental parameters and A. robustus density. There was heterogeneity in the physicochemical parameters measured among the reservoirs. The organic pollution index of the reservoir waters ranged between 2.5 (strong organic pollution) and 3.75 (moderate organic pollution). Acanthocyclops robustus was a perennial species in all four reservoirs. The density of the species varied at a spatiotemporal scale; the highest levels were observed at Kedarra reservoir (317,542 ind./L) and the lowest density was found at Cheurfas II reservoir (41,692 ind./L). Results showed that the species was very sensitive to eutrophication; its density was positively correlated with transparency and the organic pollution index, and negatively with conductivity, calcium, suspended matter, NH4, and DBO5. The OPI highlighted the pollution levels of the different reservoirs studied. The study of A. robustus dynamics showed that the species is strongly affected by ecological factors

Ethyl 3-(2-chloro-5,8-dimeth­oxy­quinolin-3-yl)-2-cyano­oxirane-2-carboxyl­ate

The title mol­ecule, C17H15ClN2O5, contains a quinolyl unit linked to a functionalized oxirane system with a 2,3-trans arrangement of the substituents (ester group versus quinol­yl). The structure can be described as being built up from zigzag layers parallel to (10). The heterocyclic ring of the quinolyl unit forms a dihedral angle of 60.05 (1)° with the oxirane plane. The crystal packing is stabilized by inter­molecular C—H⋯O and C—H⋯N hydrogen bonding, resulting in the formation of an infinite three-dimensional network and reinforcing the cohesion between the layers

How a bioindicator (or cosmopolite) copepod vary between reservoirs of different trophic state ? A case from Algeria

The effects of physicochemical parameters on the dynamics of Acanthocyclops robustus in four reservoirs (Kedarra, Gargar, Cheurfas II, and Ghrib) located in the western and central regions of Algeria were studied. Water samples were taken seasonally along a year. The densities of A. robustus were not stable during the year ; they depended on variations in the environmental factors such as the transparency of water, orthophosphates, conductivity, BOD5, and nutrients. Statistical tests were used to demonstrate the interactions between the environmental parameters and A. robustus density. There was heterogeneity in the physicochemical parameters measured among the reservoirs. The organic pollution index of the reservoir waters ranged between 2.5 (strong organic pollution) and 3.75 (moderate organic pollution). Acanthocyclops robustus was a perennial species in all four reservoirs. The density of the species varied at a spatiotemporal scale ; the highest levels were observed at Kedarra reservoir (317,542 ind./L) and the lowest density was found at Cheurfas II reservoir (41,692 ind./L). Results showed that the species was very sensitive to eutrophication ; its density was positively correlated with transparency and the organic pollution index, and negatively with conductivity, calcium, suspended matter, NH4, and DBO5. The OPI highlighted the pollution levels of the different reservoirs studied. The study of A. robustus dynamics showed that the species is strongly affected by ecological factors.Comment un copépode bioindicateur (ou cosmopolite) varie-t-il dans des réservoirs de qualité trophique différente ? Un cas en Algérie. Les effets de paramètres physicochimiques sur la dynamique d’Acanthocyclops robustus dans quatre réservoirs (Kedarra, Gargar, Cheurfas II et Ghrib) situés dans les régions de l’ouest et du centre de l’Algérie ont été étudiés. Des échantillons d’eau ont été prélevés saisonnièrement le long d’une année. Les densités d’A. robustus n’étaient pas stables au cours de l’année ; elles dépendaient des variations des facteurs environnementaux. Des tests statistiques ont été utilisés pour démontrer les interactions entre les paramètres environnementaux et la densité d’A. robustus. Il y avait une hétérogénéité dans les paramètres physico-chimiques mesurés selon les réservoirs. L’indice de pollution organique des eaux du réservoir variait entre 2,5 (forte pollution organique) et 3,75 (pollution organique modérée). Acanthocyclops robustus est une espèce pérenne dans les quatre réservoirs. La densité de l’espèce variait selon l’échelle spatio-temporelle ; la densité la plus élevée a été observée à Kedarra (317,542 ind./ L) et la plus faible a été trouvée dans le réservoir de Cheurfas II (41,692 ind./ L). Les résultats ont montré que l’espèce était très sensible à l’eutrophisation ; sa densité était corrélée positivement avec la transparence et l’indice de pollution organique, mais négativement avec la conductivité, le calcium, les matières en suspension, NH4 et DBO5.Alliouche Faiza, Arab Abdeslem. How a bioindicator (or cosmopolite) copepod vary between reservoirs of different trophic state ? A case from Algeria . In: Revue d'Écologie (La Terre et La Vie), tome 73, n°4, 2018. pp. 559-568

3-(1H-1,3-Benzimidazol-2-yl)-2,7-dimethoxyquinoline

In the title molecule, C18H15N3O2, the dihedral angle between the quinoline and benzimidazole ring systems is 23.57 (5)°. The C atoms of the methoxy groups are both close to being coplanar with their attached ring systems [deviations = 0.193 (2) and −0.020 (2) Å]. An intramolecular N—H...O hydrogen bond closes an S(6) ring. In the crystal, N—H...N hydrogen bonds link the molecules into C(4) chains propagating in [010]. Weak C—H...π interactions also occur

Crystal structure of (E)-1-methyl-2-[2-(2-methoxphenyl)ethenyl]-4-nitro-1H-imidazole

In the asymmetric unit of the title compound, C13H13N3O3, the 2-(2-methoxphenyl)ethenyl unit is connected to the methyl-nitroimidazole 1-methyl-4-nitro-1H-imidazole moiety. The molecule is quasi-planar and the planes of the two rings form a dihedral angle of 0.92 (11)°. The crystal packing can be described as layers parallel to the (011) plane, stabilized by intermolecular C—H...O hydrogen bonding, resulting in the formation of an infinite three-dimensional network linking these layers. Strong π–π stacking interactions are observed, viz. benzene–benzene, imidazole–imidazole and benzene–imidazole rings, with centroid–centroid distances of 3.528 (2), 3.457 (2) and 3.544 (2) Å, respectively. Intensity statistics indicated twinning by non-merohedry, with refined weighs of the twin components of 0.3687:0.6313

Crystal structure of 1-methyl-2-[(E)-2-(4-methylphenyl)ethenyl]-4-nitro-1H-imidazole

In the title molecule, C13H13N3O2, the planes of the benzene and imidazole rings form a dihedral angle of 7.72 (5)°. In the crystal, molecules are linked by weak C—H...N and C—H...O hydrogen bonds, forming layers parallel to (100). A weak C—H...π interaction connects these layers into a three-dimensional network. A π–π stacking interaction, with a centroid–centroid distance of 3.5373 (9) Å, is also observed

Characterization and In vitro bioactivity of chitosan/hydroxyapatite composite membrane prepared by freeze-gelation method

This work reports the properties of highly porous (>80%) membrane Chitosan/Hydroxyapatite (Cs/HA) composites obtained by the freeze-gelation processing route. These materials are of great interest for bone regeneration applications due to their ability to nucleate calcium phosphates in presence of simulated body fluid (SBF). The membranes porosity and bioactivity can be easily controlled by adding various amounts of hydroxyapatite to chitosan solution. The structural properties of the composite membrane of Cs/HA at various weight ratio (Cs/HA=70/30, 50/50 and 30/70) have been investigated by scanning electron microscopy (SEM), porosity measurements and FTIR spectroscopy. The surface of the composite membranes after immersion in SBF during more than 14 days shows a regular Ca-P layer as evidenced by FTIR spectroscopy and ICP analysis. These results suggest the potential interest of the Chitosan/hydroxyapatite composite membranes prepared by freeze-gelation process in bone regeneration and especially of the Cs/HA membrane with a ratio of 70/3