Informe de la Campaña ARGELIA0203-DP para la evaluación de recursos demersales profundos en las costas de Argelia (Mediterráneo Sud-Occidental)

RESUMEN: Del 5 al 24 de marzo de 2003 se llevó a cabo la campaña de prospección pesquera con arrastre de fondo ARGELIA0203-DP en aguas de Argelia, a bordo del B/O Vizconde de Eza. Se realizaron 55 pescas (3 nulas) entre 200 y 800 m de profundidad. Se presentan los resultados de las capturas realizadas en esta campaña y se analizan los índices de abundancia y biomasa de las especies más importantes, por sector y área geográficos y estrato batimétrico, así como su distribución de tallas por sector geográfico y estrato batimétrico. Se comparan los rendimientos y las tallas obtenidos con los de otras campañas realizadas en el Mediterráneo (MEDITS y BALAR)RÉSUME: Rapport de la campagne ARGELIA0203-DP portant evaluation des ressources demersales des côtes Algeriennes (Mediterrane sud-occidental).- Du 05 au 24 Mars 2003, s’est réalisée une campagne de prospection par chalutage du fond ARGELIA0203-DP des côtes Algériennes, abord du B/O Vizconde de Eza. 55 traits de pêche (3 annulées) ont été effectue entre 200 et 800 m de profondeur. Les résultats des captures réalisées durant cette campagne et l’analyse des indices d’abondance et biomasse des espèces les plus importantes sont présentés, par secteur, par aire géographique et strate bathymétrique, ainsi que leurs distributions de tailles par secteur géographique et strate bathymétrique. Les rendements et les tailles obtenus ont fait l’objet d’une comparaison avec les autres campagnes réalisées dans la Méditerranée (MEDITS et BALAR)ABSTRACT: Report of the ARGELIA0203-DP survey for the assessment of the deep-sea demersal resources off Algerian coasts (southwestern Mediterranean).- From March 5th to 24th 2003 the bottom-trawl survey ARGELIA0203-DP was developed in waters off Argelia, on board R/V Vizconde de Eza. Fifty-five hauls (3 null) were carried out between 200 and 800 m depth. The results of the captures obtained during this survey are shown and abundance and biomass indexes of the most important species are analyzed by geographic sector and area, and bathymetric stratum, as their size distribution by geographic sector and bathymetric stratum. Yields and sizes obtained are compared to those from other surveys carried out in the Mediterranean (MEDITS and BALAR)

First Observation of Microcystins in Tunisian inland waters: a threat to river mouths and lagoon ecosystems

1 - Microcystin pollution is known to affect different types of inland water bodies: river mouths and coastal lagoons may be affected by local production as well as by transportation through the freshwater network. Physicochemical and biological water quality, including the total microcystin concentration, was investigated from July to December 2003 in the reservoir Hjar, Tunisia. 2 - Microcystin levels and characterization of the different microcystin variants present were measured by protein phosphatase inhibition assays (PP2A) and by high performance liquid chromatography coupled to diode array detector and tandem mass spectrometry, respectively. The microscopic examination of the phytoplankton samples showed the dominance of the Oscillatoria and Pseudoanabaena genera. The total (particulate and dissolved) microcystin concentrations in the reservoir water varied between 23.4 and 7455.2 ng/l microcystin-LR equivalent per liter. 3 - The highest MCYST concentration was observed in November 2003. The analysis of the field bloom extract from this month by HPLC coupled to photodiode-array detector revealed the presence of five peaks having characteristic spectra of microcystins with a maximum of absorbance at 238 nm. HPLC/MS/MS analysis of this sample demonstrated the presence of three variants of microcystins: microcystin-LR (MCYST-LR), microcystin- (MCYST-RR), microcystin- (MCYST-YR). Therefore, estuaries of rivers contaminated by cyanobacteria toxins may play an important role on the transfer of these cyanotoxins through food chains

The effects of Ag, Mg, and Pr doping on the superconductivity and structure of BSCCO

AbstractThe influence of Ag, Mg, and Pr additions and co-additions on microstructure and phase formation of Bi2Sr2CaCu2O8+d (Bi2212) system is investigated. Polycrystalline Bi2212 samples were synthesized in air by solid state reaction method. Phase analysis, micro structural observations and magnetic properties were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and A.C. susceptibility measurements respectively. XRD results reveal two main phases (Bi-2201 and Bi2212). SEM photographs show that the substitution by Ag, Mg or Pr affects the mechanism of the grains growth. The undoped sample has a critical temperature Tc of 65 K while in the Mg and Ag containing compounds the Tc is 77 K and 75 K respectively. The Pr containing compound exhibits no superconductivity. A valence of the Pr ion higher than 3+ in the lattice supports the holefilling mechanism of the suppression of superconductivity