People-selectivity, audiovisual integration and heteromodality in the superior temporal sulcus

The functional role of the superior temporal sulcus (STS) has been implicated in a number of studies, including those investigating face perception, voice perception, and face–voice integration. However, the nature of the STS preference for these ‘social stimuli’ remains unclear, as does the location within the STS for specific types of information processing. The aim of this study was to directly examine properties of the STS in terms of selective response to social stimuli. We used functional magnetic resonance imaging (fMRI) to scan participants whilst they were presented with auditory, visual, or audiovisual stimuli of people or objects, with the intention of localising areas preferring both faces and voices (i.e., ‘people-selective’ regions) and audiovisual regions designed to specifically integrate person-related information. Results highlighted a ‘people-selective, heteromodal’ region in the trunk of the right STS which was activated by both faces and voices, and a restricted portion of the right posterior STS (pSTS) with an integrative preference for information from people, as compared to objects. These results point towards the dedicated role of the STS as a ‘social-information processing’ centre

Mathematical modeling of biogeochemical processes associated to a coccolithophorid (Emiliania huxleyi) bloom - Study of the seasonal and long-term variability of biogeochemical properties in the Black Sea using a Data Interpolating Variational Analysis (DIVA)

A OD biogeochemical model has been developed to represent coccolithophorid physiological features concerned by carbon export (primary production, active DOC excretion, TEP formation, and calcification) and susceptible to be sensitive to varying pCO2. The model is initially calibrated and validated using a large set of biogeochemical data monitored during Emiliania huxleyi blooms induced in a mesocosm experiment, under present-day pCO2 conditions. Afterwards, impacts of varying pCO2 conditions on Emiliania huxleyi physiology are investigated using biogeochemical variables monitored in mesocosms under low and high pCO2 conditions. The methodology promotes a double approach: the recalibration model parameters’ that optimizes the representation of observations from low and high pCO2 treatments, and the utilization of a RM ANOVA procedure to indicate significant differences between biogeochemical variables monitored during blooms induced in low and high pCO2 treatments. Since the early 1970’s, the Black Sea ecosystem has suffered significant ecological alterations, essentially caused by anthropogenic impacts. Dam constructions on the Danube River in combination with heavy nutrients discharge via the riverine run-off lead to strong modifications of its physical and biogeochemical properties, with final consequences consisting in an enhancement of the typical anoxic state of the deep waters. The long-term evolution of key biogeochemical variables (oxygen, hydrogen sulfide, and chlorophyll) has been studied through the reconstruction of horizontal fields, using long time data series and the DIVA interpolating tool. In addition, the examination during the best sampled period (1986-1993) of these biogeochemical variables’ fields, completed with nitrates and phosphates fields, highlighted seasonal and horizontal variability within typical sections of their profiles

Assessing ecosystem changes in the North Western shelf of the Black Sea using 3D coupled models

SESAM

Application of a data-interpolating variational analysis (DIVA) tool to physical and biogeochemical measurements covering the Black Sea

peer reviewedThe European project SESAME (Southern European Seas: Assessing and Modelling Ecosystem changes) is dedicated to the assessment of ecological changes in the Mediterranean and Black seas during these last decades. This assessment will be done by combining statistical analysis of available data and the development of a 3D hydrodynamical-biogeochemical model. Data available since 1960 for the Black Sea from the databases MEDAR and NATO have been completed with data provided by SESAME partners. These data sets have been analyzed using DIVA, a geostatistical analysis tool developed by the GHER laboratory of the University of Liège. The DIVA analysis relies on a finite element resolution, taking into account coastlines, sub-basins, and advection by ocean currents. DIVA analysis generates spatially interpolated fields for biogeochemical and physical variables. Outputs consist in sets of analysis as well as error fields, and colorimetric scaled maps related to several depth layers. Biogeochemical variables considered consist in measures of chlorophyll, inorganic nutrients concentration, and phytoplankton abundances; physical variables consist in temperature and salinity. These treatments of the Black sea data sets offer an overview of the global pattern of the Black sea biogeochemical structure, and its evolution through the time periods concerned by the project. The interpolated fields generated by the DIVA tool will be used to validate the outputs of the 3D hydrodynamical-biogeochemical model developed for the north-western shelf of the Black sea in the framework of SESAME

A mathematical modelling of bloom of the coccolithophore Emiliania huxleyi in a mesocosm experiment

info:eu-repo/semantics/publishe

A dynamic model of an experimental bloom of coccolithophores Emiliania huxleyi

A dynamic model has been developed to represent biogeochemical events observed during an experimentally induced bloom of coccolithophores Emiliania huxleyi. This bloom occurred in a mesocosm experiment (Bergen 2001 experiment) during which ecosystem development was followed over a 23-days period through changes of the stocks of inorganic nutrients (nitrate, ammonium and phosphate), dissolved inorganic carbon and pCO2, O2 concentration, pigments, particulate organic carbon and nitrogen, dissolved organic carbon, the production of Transparent Exopolymeric Particles (TEP), primary production, alkalinity, calcification and particulate inorganic carbon. The dynamic model is based on unbalanced algal growth and balanced growth for bacteria as described in Van den Meersche et al. (2004). In addition, in order to adequately reproduce the observations, the model has been extended by including an explicit description of calcification, T.E.P production and an enhanced mortality due to viruses. This last process, based on a critical promiscuity between cellular hosts and viral agents, successfully contributed to reproduce the bloom extinction as observed in the mesocosm experiment. This model will be implemented in a coupled physical-biogeochemical model of the Black Sea ecosystem in the framework of the EU Sesame project and in the Gulf of Biscay in the frame of the Belgian PEACE project