Hydromedusae (Cnidaria: Hydrozoa) from the temperate southwestern Atlantic Ocean: a review

Hydromedusae are one of the best-represented planktonic groups in waters of the South Atlantic Ocean in terms of species richness. Nevertheless, medusae of the region are inadequately known because earlier studies have been limited and restricted to few areas. During the last two decades, almost 2000 samples from 54 research cruises have been collected, mostly within the continental shelf of Argentina and Uruguay (33 - 55° S). These samples provide an opportunity to significantly augment knowledge of the richness of the medusa fauna in the southwest Atlantic. Forty species of hydromedusae (six of them new records for the area), including 15 of Anthomedusae, 14 of Leptomedusae, three of Limnomedusae, four of Narcomedusae, and four of Trachymedusae, were identified. Our results indicate that previous lists overestimated species richness of hydromedusae in the area. When misidentifications, updated species synonymies, and doubtful records are taken into account, 71 valid species are recognized here from the study area. Based upon this corrected inventory list, the data suggest that the number of species of hydromedusae decreases markedly with increasing latitude, corresponding with that observed in other planktonic groups of invertebrates.Fil: Genzano, Gabriel Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Mianzan, Hermes Walter. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Bouillon, Jean. Université Libre de Bruxelles; Bélgic

Marcel Paul-Cavallier, Jacques Walter, dirs, Organisations, médias et médiations

Dirigé par Marcel Paul-Cavallier et Jacques Walter, Organisations, médias et médiations se prête à deux niveaux de lecture. En premier lieu, les dix-huit contributions rassemblées proposent une typologie très détaillée des interdépendances complexes reliant médias et organisations, mais également des formes de communication non strictement médiatiques, ou « médiations » mises en œuvre. En second lieu, la mise en perspective de ces textes donne à l’ouvrage une portée beaucoup plus étendue, rel..

Autonomie professionnelle et rationalisations cognitives : les paradoxes dissimulés des organisations post-disciplinaires

Qu’elles soient marchandes ou non marchandes, les organisations étendent les rationalisations industrielles de la production aux activités cognitives, c’est à dire au traitement de l’information et à la mobilisation de connaissances. Ces prolongements des dispositifs disciplinaires traditionnels sont porteurs de paradoxes : les systèmes d’information intégrés rigidifient les organisations autant qu’ils les flexibilisent, l’accroissement simultané de la normalisation s’accompagne d’une exigence d’autonomie croissante, il faut développer les activités communicationnelles au travail alors que les collectifs professionnels sont de plus en plus flous. En fait, la pression des clients, des usagers, des actionnaires, induit des contraintes dynamiques qui démultiplient les sources de pouvoir et de contrôle. Il résulte de cette situation un « verrouillage symbolique » qui se manifeste à trois niveaux : contraintes à la production collective de sens dans les situations de travail, discours univoque justifiant au niveau sociétal cette réalité, évaluation publique permanente des organisations en fonction d’indicateurs de synthèse rapportant leur activité à un niveau moyen minimal. Les paradoxes continuent d’exister, mais leurs effets sont dissimulés derrière l’obligation de résultat déclinée à tous les niveaux.‪Both merchant and non-merchant organizations are extending industrial rationalizations to cognitive activities that concern in particular data and knowledge mobilization processes in working situations. These developments in traditional disciplinary mechanisms carry paradoxes. Integrated information systems increase both flexibility and rigidity in organizations. Greater respect for specifications and greater individual autonomy are required from workers. Although communicational and collective activities play a fundamental role in work, long-term working teams with intensive links between the various members are becoming exceptional. In fact, pressure from customers, users, and shareholders induce dynamic constraints that increase the number of sources of control. The consequence is a rigid three-tier structure. While people are forced to resolve production problems jointly, many discourses justify and legitimate the current socioeconomic system, and organizations undergo a permanent recording process grounded in synthetic indicators of their activity. Although paradoxes remain, their consequences are hidden behind results obligations.

Jacques Dubois, Pascal Durand, Yves Winkin, dirs, Le symbolique et le social. La réception internationale de la pensée de Pierre Bourdieu

Omniprésente dans l’œuvre de Pierre Bourdieu, la notion de « symbolique » est davantage utilisée comme un adjectif (« capital symbolique », « violence symbolique », « domination symbolique » ou « pouvoir symbolique » par exemple) que mobilisée comme substantif (« le symbolique »), comme cela devrait être le cas s’il s’agissait d’un concept construit. Or, il semble bien que ce soit dans la catégorie du symbolique que se concentre une dimension irréductiblement originale de la pensée sociologiq..

Vautorte – Forêt de Mayenne, cote 197

R. Bouillon a poursuivi et achevé la fouille, commencée en 1984, du monument mégalithique de la cote 197 en forêt de Mayenne (Gallia Préhistoire, 28, 1985, p. 383). Il s’agit d’un édifice d’une longueur totale de 9,8 m, proche des allées couvertes du nord de l’Armorique. L’entrée se trouve à l’extrémité orientale ; sa largeur est de 0,8 m environ. Un élargissement progressif conduit à une chambre de 6 m de long, aux parois grossièrement parallèles, et d’une largeur maximale de 1,4 m. Derrière..

Figures de l’individu au travail, figures du « collaborateur »

Cet article analyse comment le terme de « collaborateur », renvoie implicitement à une vision idéalisée de l’organisation, de l’individu au travail et des relations sociales. Les stratégies individuelles, l’asymétrie des rapports sociaux, les divergences d’intérêts sont passées sous silence au profit de la description performative d’une organisation cohérente, unitaire et fluide. L’étude menée dans une grande entreprise met en évidence la manière dont cette figure idéalisée relève de rationalisations communicationnelles articulées à des rationalisations industrielles plus générales, impliquant transformation des processus productifs, commerciaux et développement de nouveaux systèmes d’information.This article analyses how the word “collaborator” implicitly refers to an idealized view of organization, of work activities and social relationships. The multiplicity of the individual strategies, the divergences between interests of the different stakeholders are hidden in order to display the picture of a coherent and unitary organization. A study carried out in an important company shows that this idealized vision is a part of communicational rationalizations, embedded in more wide industrial rationalizations. Such rationalizations imply large transformations of productive and commercial processes, together with the development of new informations systems

Carbon Cycling of Lake Kivu (East Africa): Net Autotrophy in the Epilimnion and Emission of CO2 to the Atmosphere Sustained by Geogenic Inputs

We report organic and inorganic carbon distributions and fluxes in a large (>2000 km2) oligotrophic, tropical lake (Lake Kivu, East Africa), acquired during four field surveys, that captured the seasonal variations (March 2007–mid rainy season, September 2007–late dry season, June 2008–early dry season, and April 2009–late rainy season). The partial pressure of CO2 (pCO2) in surface waters of the main basin of Lake Kivu showed modest spatial (coefficient of variation between 3% and 6%), and seasonal variations with an amplitude of 163 ppm (between 579±23 ppm on average in March 2007 and 742±28 ppm on average in September 2007). The most prominent spatial feature of the pCO2 distribution was the very high pCO2 values in Kabuno Bay (a small sub-basin with little connection to the main lake) ranging between 11213 ppm and 14213 ppm (between 18 and 26 times higher than in the main basin). Surface waters of the main basin of Lake Kivu were a net source of CO2 to the atmosphere at an average rate of 10.8 mmol m−2 d−1, which is lower than the global average reported for freshwater, saline, and volcanic lakes. In Kabuno Bay, the CO2 emission to the atmosphere was on average 500.7 mmol m−2 d−1 (~46 times higher than in the main basin). Based on whole-lake mass balance of dissolved inorganic carbon (DIC) bulk concentrations and of its stable carbon isotope composition, we show that the epilimnion of Lake Kivu was net autotrophic. This is due to the modest river inputs of organic carbon owing to the small ratio of catchment area to lake surface area (2.15). The carbon budget implies that the CO2 emission to the atmosphere must be sustained by DIC inputs of geogenic origin from deep geothermal springs.AFRIVA

Production of dissolved organic matter by phytoplankton and its uptake by heterotrophic prokaryotes in large tropical lakes

In pelagic ecosystems, phytoplankton extracellular release can extensively subsidize the heterotrophic prokaryotic carbon demand. Time-course experiments were carried out to quantify primary production, phytoplankton excretion, and the microbial uptake of freshly released dissolved organic carbon (DOC) derived from phytoplankton extracellular release (DOCp) in four large tropical lakes distributed along a productivity gradient: Kivu, Edward, Albert, and Victoria. The contributions of the major heterotrophic bacterial groups to the uptake of DOCp was also analyzed in Lake Kivu, using microautoradiography coupled to catalyzed reporter deposition fluorescent in situ hybridization. The percentage of extracellular release (PER) varied across the productivity gradient, with higher values at low productivity. Furthermore, PER was significantly related to high light and low phosphate concentrations in the mixed layer and was comparatively higher in oligotrophic tropical lakes than in their temperate counterparts. Both observations suggest that environmental factors play a key role in the control of phytoplankton excretion. Standing stocks of DOCp were small and generally contributed less than 1% to the total DOC because it was rapidly assimilated by prokaryotes. In other words, there was a tight coupling between the production and the heterotrophic consumption of DOCp. None of the major phylogenetic bacterial groups that were investigated differed in their ability to take up DOCp, in contrast with earlier results reported for standard labeled single-molecule substrates (leucine, glucose, adenosine triphosphate). It supports the idea that the metabolic ability to use DOCp is widespread among heterotrophic prokaryotes. Overall, these results highlight the importance of carbon transfer between phytoplankton and bacterioplankton in large African lakes.AFRIVAL - EAGLES East African Great Lake Ecosystem Sensitivity to Changes - CAKI Cycle du Carbone et des Nutriments au Lac Kivu - MICKI Microbial Diversity and Processes in Lake Kiv

De la communication organisationnelle aux « approches communicationnelles » des organisations : glissement paradigmatique et migrations conceptuelles

Les travaux relatifs aux questions informationnelles et communicationnelles associées aux organisations se sont multipliés depuis une quinzaine d’années, au travers de nombreuses journées d’études, colloques et ouvrages…, la revue « Communication et Organisation » occupant une place centrale dans cette dynamique. Une étude des productions scientifiques des vingt dernières années montre que les objets étudiés se sont inscrits dans des espaces de plus en plus étendus. Interrogeant initialement ..

Heart rate variability in hypothyroid patients:a systematic review and meta-analysis

INTRODUCTION: Hypothyroidism may be associated with changes in the autonomic regulation of the cardiovascular system, which may have clinical implications. OBJECTIVE: To conduct a systematic review and meta-analysis on the impact of hypothyroidism on HRV. MATERIALS AND METHODS: PubMed, Cochrane, Embase and Google Scholar were searched until 20 August 2021 for articles reporting HRV parameters in untreated hypothyroidism and healthy controls. Random-effects meta-analysis were stratified by degree of hypothyroidism for each HRV parameters: RR intervals (or normal to normal-NN intervals), SDNN (standard deviation of RR intervals), RMSSD (square root of the mean difference of successive RR intervals), pNN50 (percentage of RR intervals with >50ms variation), total power (TP), LFnu (low-frequency normalized unit), HFnu (high-frequency), VLF (very low frequency), and LF/HF ratio. RESULTS: We included 17 studies with 11438 patients: 1163 hypothyroid patients and 10275 healthy controls. There was a decrease in SDNN (effect size = -1.27, 95% CI -1.72 to -0.83), RMSSD (-1.66, -2.32 to -1.00), pNN50 (-1.41, -1.98 to -0.84), TP (-1.55, -2.1 to -1.00), HFnu (-1.21, -1.78 to -0.63) with an increase in LFnu (1.14, 0.63 to 1.66) and LF/HF ratio (1.26, 0.71 to 1.81) (p <0.001). HRV alteration increased with severity of hypothyroidism. CONCLUSIONS: Hypothyroidism is associated with a decreased HRV, that may be explained by molecular mechanisms involving catecholamines and by the effect of TSH on HRV. The increased sympathetic and decreased parasympathetic activity may have clinical implications