Green Edge ice camp campaigns : understanding the processes controlling the under-ice Arctic phytoplankton spring bloom

The Green Edge initiative was developed to investigate the processes controlling the primary productivity and fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiqtarjuaq Island in Baffin Bay (67.4797∘ N, 63.7895∘ W). During both expeditions, a large suite of physical, chemical and biological variables was measured beneath a consolidated sea-ice cover from the surface to the bottom (at 360 m depth) to better understand the factors driving the PSB. Key variables, such as conservative temperature, absolute salinity, radiance, irradiance, nutrient concentrations, chlorophyll a concentration, bacteria, phytoplankton and zooplankton abundance and taxonomy, and carbon stocks and fluxes were routinely measured at the ice camp. Meteorological and snow-relevant variables were also monitored. Here, we present the results of a joint effort to tidy and standardize the collected datasets, which will facilitate their reuse in other Arctic studies

Early diagnosis of Alzheimer's disease using cortical thickness: impact of cognitive reserve

Brain atrophy measured by magnetic resonance structural imaging has been proposed as a surrogate marker for the early diagnosis of Alzheimer's disease. Studies on large samples are still required to determine its practical interest at the individual level, especially with regards to the capacity of anatomical magnetic resonance imaging to disentangle the confounding role of the cognitive reserve in the early diagnosis of Alzheimer's disease. One hundred and thirty healthy controls, 122 subjects with mild cognitive impairment of the amnestic type and 130 Alzheimer's disease patients were included from the ADNI database and followed up for 24 months. After 24 months, 72 amnestic mild cognitive impairment had converted to Alzheimer's disease (referred to as progressive mild cognitive impairment, as opposed to stable mild cognitive impairment). For each subject, cortical thickness was measured on the baseline magnetic resonance imaging volume. The resulting cortical thickness map was parcellated into 22 regions and a normalized thickness index was computed using the subset of regions (right medial temporal, left lateral temporal, right posterior cingulate) that optimally distinguished stable mild cognitive impairment from progressive mild cognitive impairment. We tested the ability of baseline normalized thickness index to predict evolution from amnestic mild cognitive impairment to Alzheimer's disease and compared it to the predictive values of the main cognitive scores at baseline. In addition, we studied the relationship between the normalized thickness index, the education level and the timeline of conversion to Alzheimer's disease. Normalized thickness index at baseline differed significantly among all the four diagnosis groups (P < 0.001) and correctly distinguished Alzheimer's disease patients from healthy controls with an 85% cross-validated accuracy. Normalized thickness index also correctly predicted evolution to Alzheimer's disease for 76% of amnestic mild cognitive impairment subjects after cross-validation, thus showing an advantage over cognitive scores (range 63–72%). Moreover, progressive mild cognitive impairment subjects, who converted later than 1 year after baseline, showed a significantly higher education level than those who converted earlier than 1 year after baseline. Using a normalized thickness index-based criterion may help with early diagnosis of Alzheimer's disease at the individual level, especially for highly educated subjects, up to 24 months before clinical criteria for Alzheimer's disease diagnosis are met

Testing for the Dual-Route Cascade Reading Model in the Brain: An fMRI Effective Connectivity Account of an Efficient Reading Style

Neuropsychological data about the forms of acquired reading impairment provide a strong basis for the theoretical framework of the dual-route cascade (DRC) model which is predictive of reading performance. However, lesions are often extensive and heterogeneous, thus making it difficult to establish precise functional anatomical correlates. Here, we provide a connective neural account in the aim of accommodating the main principles of the DRC framework and to make predictions on reading skill. We located prominent reading areas using fMRI and applied structural equation modeling to pinpoint distinct neural pathways. Functionality of regions together with neural network dissociations between words and pseudowords corroborate the existing neuroanatomical view on the DRC and provide a novel outlook on the sub-regions involved. In a similar vein, congruent (or incongruent) reliance of pathways, that is reliance on the word (or pseudoword) pathway during word reading and on the pseudoword (or word) pathway during pseudoword reading predicted good (or poor) reading performance as assessed by out-of-magnet reading tests. Finally, inter-individual analysis unraveled an efficient reading style mirroring pathway reliance as a function of the fingerprint of the stimulus to be read, suggesting an optimal pattern of cerebral information trafficking which leads to high reading performance

Bases neurales de l'interaction temps-mouvement (étude en IRMf)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Vector generalized linear model applied to cortical thickness in neurodegenerative disease follow-up

International audienceNeurodegenerative disease progressively affects cortical morphology and causes a gradual decline of the cognitive abilities. Our goal was to develop a methodology to estimate a spatio-temporal signature associated with the disease's evolution in terms of cortical areas involved in disease evolution or stabilization. We have tested our approach on a longitudinal study of the cortical thickness (CTh)

Mesure de l'épaisseur corticale en IRM (application au diagnostic précoce individuel de la maladie d'Alzheimer et à la notion de réserve cognitive)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Etude de l'efficacité mécanique d'une vis hydrodynamique

L'objectif de cet article est d'évaluer l'efficacité mécanique d'une vis hydrodynamique, dont le but est de convertir une puissance hydraulique en puissance électrique. Dans un premier temps, un modèle théorique issu de la littérature est présenté et implémenté afin d'étudier l'influence des différents paramètres d'un tel système sur son efficacité. Dans un second temps, une maquette à l'échelle 1/5 et son instrumentation sont présentées. Les résultats obtenus suite à une série d'essais permettent de recaler certains paramètres empiriques du modèle et d'effectuer une première comparaison entre efficacités réelles et théoriques.

Le gisement de Pont-de-Planches (Haute-Saône) : cadre paléo-

International audienceTHE PALAEOLITHIC SITE OF PONT-DE-PLANCHES (HAUTE-SAÔNE, FRANCE): PALAEOENVIRONNEMENT DATASAND DATATIONS OF MIDDLE PALAEOLITHIC AND UPPER PALAEOLITHIC OCCUPATIONSTwice the open-air site of Pont-de-Planches has been occupied by men from palaeolithic : the oldest occupation is around50 ka (marine isotopic stage MIS 3) and is characterized by a bifacial tools industry called micoquian while the most recent one isa gravettian occupation. From many aspects, this open air-site looks exceptional for that region. It gives us a stratigraphy sequencewhich goes from the middle Pleistocene to Holocene, and compares with Ajoie region in Switherland, 100 km distant from the site. Itgives us the first bison discovered in open-air site. This report from the principal specialists present the initial synthesis of the site, thedating of sediments by thermoluminescence, paleontological data on the teeth and cranian of a Bison priscus associated to gravettianoccupation, and general descriptions of the typology and technological aspects of the two industries separated by 35 000 years. Thecomposition of the micoquian industry shows many common lithic features shared with South Germany or Danubia regions. All this,helps us to follow the incursions of Neanderthal and modern humans during the stage 3 and 2 along a pan-European east-west axis.A deux reprises, le gisement de plein air de Pont-de-Planches a été fréquenté par les hommes du Paléolithique : la plusancienne occupation, située autour de - 50 ka (stade isotopique marin SIM 3), est caractérisée par une industrie rattachable auMicoquien, la plus récente correspond à une occupation gravettienne. Par divers aspects, ce site de plein air paraît exceptionnel pourla région étudiée. Il fournit une séquence stratigraphique, allant du Pléistocène moyen jusqu’à l’Holocène, comparable à celle del’Ajoie en Suisse distante d’une centaine de kilomètres. Il a par ailleurs livré le premier bison trouvé en contexte de plein air dans larégion. Ce travail pluri-disciplinaire présente les premiers résultats synthétiques sur le gisement, qu’il s’agisse de données stratigra- phiques, des résultats des datations par thermoluminescence sur sédiments, des données paléontologiques portant notamment sur desdonnées faunistiques dentaires et crâniennes de Bison priscus associés à l’occupation gravettienne ainsi que les premiers élémentstypologiques et technologiques correspondant à ces deux occupations séparées de 35 000 ans l’une de l’autre. La composition del’industrie micoquienne présente de nombreuses affinités avec celles de l’Allemagne ou du Danube et nous aide à appréhender lesincursions des populations selon un axe est/ouest au cours du stade