Carbon Dynamics Along the Seine River Network: Insight From a Coupled Estuarine/River Modeling Approach

The Seine river discharges over 700 Gg of carbon (C) every year into the sea mostly under the form of dissolved inorganic carbon (DIC) and emits 445 Gg under the form of carbon dioxide (CO2) to the atmosphere over its entire river network. The watershed, which drains 76,000 km2, is heavily populated with 18 106 inhabitants and is thus submitted to large anthropic pressure. The offline coupling of two Reactive Transport Models is used to understand the complex spatial and temporal dynamics of carbon, oxygen and nutrients and quantify the CO2 exchange at the air-water interface along the main axis of the river. The estuarine section of the Seine is simulated by the generic estuarine model C-GEM (for Carbon Generic Estuarine Model), while the upstream part of the network, devoid of tidal influence is simulated by the pyNuts-Riverstrahler modeling platform which also includes an explicit representation of the drainage network ecological functioning. Our simulations provide a process-based representation of nutrients, oxygen, total organic carbon (TOC) and the carbonate system (DIC and alkalinity) over the entire year 2010. Our coupled modeling chain allows quantifying the respective contributions of the estuarine and freshwater sections of the system in the removal of carbon as well as following the fate of TOC and DIC along the river network. Our results also allow calculating an integrated carbon budget of the Seine river network for year 2010

Atrial fibrillation and cardiac rehabilitation: an overview.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia, and its frequency will only continue to increase in the future. Despite available drug and electrophysical treatments, death and functional restrictions due to AF are still common. More comprehensive standards of care are therefore needed. PURPOSE: After a foreword regarding the link between physical activity and AF, this article aims to give to the clinician an overview of the benefits he may expect or not when including patients suffering from AF in a cardiac rehabilitation programme. METHOD: We selected prospective, randomised controlled trials published during the past 10 years and referenced in the PubMed Database evaluating the safety of rehabilitation and/or its impact on AF incidence or tolerance, and tried to summarise them to propose a narrative review. CONCLUSION: Cardiac rehabilitation, along with moderate and regular physical activity, has been proven to reduce the time in arrhythmia of patients with paroxysmal and persistent AF. In chronic AF, cardiac rehabilitation may decrease the resting ventricular response rate in patients and therefore improve symptoms linked to arrhythmia. These studies have managed to demonstrate cardiac rehabilitation as a safe and manageable option for AF patients, without serious risk of additional side effects. Its efficiency to limit the occurrence of serious undesirable outcomes, such as mortality and hospitalisation, has not been adequately demonstrated, likely due to the small scale of most studies and lack of long-term follow-up. Large-scale and long-term studies are thus desirable

TreeJ: an ImageJ plugin for interactive cell lineage reconstruction from static images.

Acknowledgements: We thank Katia Belcram for the images, and Ignacio Arganda-Carreras and David Legland for their help with Java programming.BACKGROUND: With the emergence of deep-learning methods, tools are needed to capture and standardize image annotations made by experimentalists. In developmental biology, cell lineages are generally reconstructed from time-lapse data. However, some tissues need to be fixed to be accessible or to improve the staining. In this case, classical software do not offer the possibility of generating any lineage. Because of their rigid cell walls, plants present the advantage of keeping traces of the cell division history over successive generations in the cell patterns. To record this information despite having only a static image, dedicated tools are required. RESULTS: We developed an interface to assist users in the building and editing of a lineage tree from a 3D labeled image. Each cell within the tree can be tagged. From the created tree, cells of a sub-tree or cells sharing the same tag can be extracted. The tree can be exported in a format compatible with dedicated software for advanced graph visualization and manipulation. CONCLUSIONS: The TreeJ plugin for ImageJ/Fiji allows the user to generate and manipulate a lineage tree structure. The tree is compatible with other software to analyze the tree organization at the graphical level and at the cell pattern level. The code source is available at https://github.com/L-EL/TreeJ

Optical characterizations of “P-down” bonded InP pump lasers

International audienceWe investigate the effects of the assembly process and its parameters on the optical polarization in InP pump lasers for telecommunications. Different measurements were performed for this study, such as degree of polarization of the laser emission below and above the threshold current, as well as the evaluation of the induced strain in the materials by measuring the degree of linear polarization of the photo-luminescence. We demonstrate that the soldering process parameters can affect the emission polarization both below and above the laser threshold current

Large-scale analysis and computer modeling reveal hidden regularities behind variability of cell division patterns in Arabidopsis thaliana embryogenesis

Abstract Noise plays a major role in cellular processes and in the development of tissues and organs. Several studies have examined the origin, the integration or the accommodation of noise in gene expression, cell growth and elaboration of organ shape. By contrast, much less is known about variability in cell division plane positioning, its origin and links with cell geometry, and its impact on tissue organization. Taking advantage of the first-stereotyped-then-variable division patterns in the embryo of the model plant Arabidopsis thaliana, we combined 3D imaging and quantitative cell shape and cell lineage analysis together with mathematical and computer modeling to perform a large scale, systematic analysis of variability in division plane orientation. Our results reveal that, paradoxically, variability in cell division patterns of Arabidopsis embryos is accompanied by a progressive reduction of cell shape heterogeneity. The paradox is solved by showing that variability operates within a reduced repertoire of possible division plane orientations that is related to cell geometry. We show that in several domains of the embryo, a recently proposed geometrical division rule recapitulates observed variable patterns, thus suggesting that variable patterns emerge from deterministic principles operating in a variable geometrical context. Our work highlights the importance of emerging patterns in the plant embryo under iterated division principles, but also reveal domains where deviations between rule predictions and experimental observations point to additional regulatory mechanisms

Carbon Dynamics Along the Seine River Network: Insight From a Coupled Estuarine/River Modeling Approach

International audienceThe Seine river discharges over 700 Gg of carbon (C) every year into the sea mostly under the form of dissolved inorganic carbon (DIC) and emits 445 Gg under the form of carbon dioxide (CO2) to the atmosphere over its entire river network. The watershed, which drains 76,000 km2, is heavily populated with 18 106 inhabitants and is thus submitted to large anthropic pressure. The offline coupling of two Reactive Transport Models is used to understand the complex spatial and temporal dynamics of carbon, oxygen and nutrients and quantify the CO2 exchange at the air-water interface along the main axis of the river. The estuarine section of the Seine is simulated by the generic estuarine model C-GEM (for Carbon Generic Estuarine Model), while the upstream part of the network, devoid of tidal influence is simulated by the pyNuts-Riverstrahler modeling platform which also includes an explicit representation of the drainage network ecological functioning. Our simulations provide a process-based representation of nutrients, oxygen, total organic carbon (TOC) and the carbonate system (DIC and alkalinity) over the entire year 2010. Our coupled modeling chain allows quantifying the respective contributions of the estuarine and freshwater sections of the system in the removal of carbon as well as following the fate of TOC and DIC along the river network. Our results also allow calculating an integrated carbon budget of the Seine river network for year 2010

Micro-PL characterization of oxide-confined GaAs VCSEL operating at 850 nm

International audienc

DOP characterization of oxide-confined GaAs based VCSEL operating at 850 nm

International audienc

Late failure of atrial septal defect occluder device.

Percutaneous device implantation is the method of choice for secundum atrial septal defect (ASD) closure. Some occluder devices use thin polymeric membranes that can undergo unexpected degradation. This can lead to early failure of the implant, typically within weeks or months after implantation. Here we report a case of delayed device failure. [...