Contribution à l'écologie de quelques taxons du zooplancton de Côte d'Ivoire. 3 - Larves de décapodes et lucifer

The warm season is the abundance period of the planktonic larval stages of Decapod Crustacea and of Lucifer faxonii in Ivoirian waters. Two or three maxima occur each year during the enrichments interrupting the warm and oligotropic season: February (small upwellings), June - some years - (first rains) and September - November (flood of rivers, end of cold season). Vertical distribution follows seasonal variations and varies little among the taxons. In a general way, Decapod larvae and Lucifer inhabit superficial layers in cold season and sink down during the warm season. It allows them to follow the maximum of primary production. Lucifer faxonii is breeding almost the year long. Breeds succede at rate of 3,7 weeks approximately

Contribution à l'écologie de quelques taxons du zooplancton de Côte d'Ivoire. 4 - Euphausiaces

Euphausiids vertical distribution on the Côte d'Ivoire continental shelf during different seasons, average zonal distrubution, mean distance to the shore, and seasonal variations in abundance computed for five years, suggest that the appearance, and the shifting of euphausiids across and along the shelf are related with the variations of the distance from the shore of the ivorian under-current. The author reports that Nyctiphanes capensis has not been found in the region

Note sur l'évolution des populations de Copépodes pélagiques de l'upwelling mauritanien (mars-avril 1972)

The evolution of a plankton copepod population in the Mauritania upwelling was studied by following a drogue for 9 days, from the point of upwelling till the water-mass dives under offshore waters. The Shannon index of specific diversity and the tropic structure allow separation into several stages in the studied succession. The upwelling brings near the shore a rather poor, highly diverse fauna, with a low filter-feeder rate. The phytoplanktonic development induces an increase in the copepod number. The filter-feeders become dominant and the diversity decreases. When the increase of copepod number stops, the diversity decreases and the omnivore and carnivore rate increases

Contribution à l'écologie de quelques taxons du zooplancton de Côte d'Ivoire. 2 - Dolioles, Salpes, Appendiculaires

The seasonal variations of vertical distribution and abundance over the shelf are investigated for Doliolids, Salps and Larvacea. The 3 groups present many similar ecological features. Two maxima of abundance occur during the little and main cool seasons. The second maximum is usually the most important, except for Salps. The 3 taxons inhabit more superficial layers in cool than in warm seasons. This allows them to follow the phytoplankton maximum which drifts near the thermocline during the warm season. Pelagic Tunicates come back to the phytoplankton enrichment areas by the deeper Ivorian under-current. A relationship between the vertical distribution pattern and the life cycle (sexual or asexual generation) is suggested

Dix ans de mesures de biomasses de zooplancton a la station cotière d'Abidjan: 1969-1979

Graphs of variations of zooplankton biomasses expressed as ash-free dry weight (i.e. organic matter) are presented for the 1969-1979 period. The graph of the average year shows: an enrichment season from mid-July till mid-November in which the biomass is 2.3 times higher than the rest of the year and characterized by a slight decrease of the biomass in late August or early September. The warm season is divided into a period of moderate biomass from November till February, a period of moderate biomass from November till February and a period of steady decline of the biomass till the start of the upwelling at the end of June

Copépodes pélagiques du plateau ivoirien. Utilisation de I'analyse des correspondances dans l'étude des variations saisonnières

Several 'analyses factorielles des correspondences' were used with the numerical data of planktonic copepods issued from a 1 year sampling programme at different stations of the Ivorian shelf. The main results were the following: (1) 'Ecological seasons' approximately corresponding to hydrological seasons may be defined for planktonic populations. (2) Each 'season' is characterized by one group of species, whose maximum abundance occurs in this period. (3) The same definition of ecological season is obtained whether all species present are used or whether only the most important ones are used. (4) The first principal axes may be interpreted as temperature and salinity or as the station's distance from shore

Copépodes pélagiques du plateau ivoirien. 2 - Utilisation de l'arbre de longueur minimum dans le classement des récoltes

The minimum spanning tree algorithm is used to classify two sets of planktonic copepod samples. This algorithm links the samples the distance of which is minimum, without doing a loop, so that the sum of the segment lengths is minimum. The authors estimated the distance between samples by 2 different ways: by a coefficient of association the Jaccard's index - and by the x2 distance. Jaccard's index is not retained but the use of the x2 distance allows comparison with the 'analyse factorielle des correspondances'. The results are discussed from an ecological point of view

Mapping the complete glycoproteome of virion-derived HIV-1 gp120 provides insights into broadly neutralizing antibody binding

The surface envelope glycoprotein (SU) of Human immunodeficiency virus type 1 (HIV-1), gp120SU plays an essential role in virus binding to target CD4+ T-cells and is a major vaccine target. Gp120 has remarkably high levels of N-linked glycosylation and there is considerable evidence that this “glycan shield” can help protect the virus from antibody-mediated neutralization. In recent years, however, it has become clear that gp120 glycosylation can also be included in the targets of recognition by some of the most potent broadly neutralizing antibodies. Knowing the site-specific glycosylation of gp120 can facilitate the rational design of glycopeptide antigens for HIV vaccine development. While most prior studies have focused on glycan analysis of recombinant forms of gp120, here we report the first systematic glycosylation site analysis of gp120 derived from virions produced by infected T lymphoid cells and show that a single site is exclusively substituted with complex glycans. These results should help guide the design of vaccine immunogens

Development of a quality assurance process for the SoLid experiment

The SoLid experiment has been designed to search for an oscillation pattern induced by a light sterile neutrino state, utilising the BR2 reactor of SCK circle CEN, in Belgium. The detector leverages a new hybrid technology, utilising two distinct scintillators in a cubic array, creating a highly segmented detector volume. A combination of 5 cm cubic polyvinyltoluene cells, with (LiF)-Li-6:ZnS(Ag) sheets on two faces of each cube, facilitate reconstruction of the neutrino signals. Whilst the high granularity provides a powerful toolset to discriminate backgrounds; by itself the segmentation also represents a challenge in terms of homogeneity and calibration, for a consistent detector response. The search for this light sterile neutrino implies a sensitivity to distortions of around O(10)% in the energy spectrum of reactor (v) over bare. Hence, a very good neutron detection efficiency, light yield and homogeneous detector response are critical for data validation. The minimal requirements for the SoLid physics program are a light yield and a neutron detection efficiency larger than 40 PA/MeV/cube and 50% respectively. In order to guarantee these minimal requirements, the collaboration developed a rigorous quality assurance process for all 12800 cubic cells of the detector. To carry out the quality assurance process, an automated calibration system called CALIPSO was designed and constructed. CALIPSO provides precise, automatic placement of radioactive sources in front of each cube of a given detector plane (16 x 16 cubes). A combination of Na-22, Cf-252 and AmBe gamma and neutron sources were used by CALIPSO during the quality assurance process. Initially, the scanning identified defective components allowing for repair during initial construction of the SoLid detector. Secondly, a full analysis of the calibration data revealed initial estimations for the light yield of over 60 PA/MeV and neutron reconstruction efficiency of 68%, validating the SoLid physics requirements