On the Robustness of Democratic Electoral Processes to Computational Propaganda

There is growing evidence of systematic attempts to influence democratic elections by controlled and digitally organized dissemination of fake news. This raises the question of the intrinsic robustness of democratic electoral processes against external influences. Particularly interesting is to identify the social characteristics of a voter population that renders it more resilient against opinion manipulation. Equally important is to determine which of the existing democratic electoral systems is more robust to external influences. Here we construct a mathematical electoral model to address these two questions. We find that electorates are more resilient against opinion manipulations (i) if they are less polarized and (ii) when voters interact more with each other, regardless of their opinion differences, and that (iii) electoral systems based on proportional representation are generally the most robust. Our model qualitatively captures the volatility of the US House of Representatives elections. We take this as a solid validation of our approach.Comment: Main text: 26 pages, 6 figures. Supplementary information: 14 pages, 9 figure

Fluctuation-Based Super-Resolution Traction Force Microscopy

Cellular mechanics play a crucial role in tissue homeostasis and are often misregulated in disease. Traction force microscopy is one of the key methods that has enabled researchers to study fundamental aspects of mechanobiology; however, traction force microscopy is limited by poor resolution. Here, we propose a simplified protocol and imaging strategy that enhances the output of traction force microscopy by increasing i) achievable bead density and ii) the accuracy of bead tracking. Our approach relies on super-resolution microscopy, enabled by fluorescence fluctuation analysis. Our pipeline can be used on spinning-disk confocal or widefield microscopes and is compatible with available analysis software. In addition, we demonstrate that our workflow can be used to gain biologically relevant information and is suitable for fast long-term live measurement of traction forces even in light-sensitive cells. Finally, using fluctuation-based traction force microscopy, we observe that filopodia align to the force field generated by focal adhesions

Evaluation of Ablation Patterns Using a Biophysical Model of Atrial Fibrillation

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia. Surgical/Radiofrequency (RF) ablation is a therapeutic procedure that consists of creating lines of conduction block to interrupt AF. The present study evaluated 13 different ablation patterns by means of a biophysical model of the human atria. In this model, ablation lines were abruptly applied transmurally during simulated sustained AF, and success rate, time to AF termination and average beat-to-beat interval were documented. The gold standard Cox's Maze III procedure was taken as reference. The effectiveness of twelve less invasive patterns was compared to it. In some of these incomplete lines (entailing a gap) were simulated. Finally, the computer simulations were compared to clinical data. The results show that the model reproduces observations made in vivo: (1) the Maze III is the most efficient ablation procedure; (2) less invasive patterns should include lines in both right and left atrium; (3) incomplete ablation lines between the pulmonary veins and the mitral valve annulus lead to uncommon flutter; (4) computer simulations of incomplete lines are consistent with clinical results of non-transumural RF ablation. Biophysical modeling may therefore be considered as a useful tool for understanding the mechanisms underlying AF therapie

CO2 streams containing associated components—A review of the thermodynamic and geochemical properties and assessment of some reactive transport codes

AbstractModelling of the impact on storage of “ CO2-associated components” has rarely been addressed so far. This review, performed within the European research project CO2ReMoVe, exposes a selection of CO2 streams compositions coming from thermal power plants emissions and those injected in pilot sites part of the CO2ReMoVe project. It highlights the lack of data coming from laboratory experiments to describe properly the physical properties of some relevant gas mixtures. The geochemical impact of only 2 components (SO2 and H2S) is evidenced by some geochemical studies. Concerning the numerical modelling, four reactive transport codes (PHREEQC, SCALE2000, TOUGHREACT and COORES) were assessed. Actual limitations lie mainly in the capacity of calculating the physical properties of the whole set of gases (CO2–O2–SO2–N2–Ar–NOx–H2S–COS–CO–H2–HCl–NH3–CH4–C2H6–H2O). The new data acquired within on-going French projects will complete the knowledge of such complex gas mixtures behaviour

The SARAF-LINAC Project for SARAF-PHASE 2

THPF005International audienceSNRC and CEA collaborate to the upgrade of theSARAF accelerator to 5 mA CW 40 MeV deuteron andproton beams (Phase 2). This paper presents the referencedesign of the SARAF-LINAC Project including a fourvane176 MHz RFQ, a MEBT and a superconducting linacmade of four five-meter cryomodules housing 26superconducting HWR cavities and 20 superconductingsolenoids. The first two identical cryomodules house lowbeta($\beta$opt = 0.091), 280 mm long (flange to flange), 176MHz HWR cavities, the two identical last cryomoduleshouse high-beta ($\beta$opt = 0.181), 410 mm long, 176 MHz,HWR cavities. The beam is focused with superconductingsolenoids located between cavities housing steering coils.A BPM is placed upstream each solenoid

On commensurable hyperbolic Coxeter groups

For Coxeter groups acting non-cocompactly but with finite covolume on real hyperbolic space Hn, new methods are presented to distinguish them up to (wide) commensurability. We exploit these ideas and determine the commensurability classes of all hyperbolic Coxeter groups whose fundamental polyhedra are pyramids over a product of two simplices of positive dimensions

Improving the knock-in efficiency of the MOF-encapsulated CRISPR/Cas9 system through controllable embedding structures

Appropriate tuning of robust artificial coatings can not only enhance intracellular delivery but also preserve the biological functions of genetic molecules in gene based therapies. Here, we report a strategy to synthesize controllable nanostructures in situ by encapsulating CRISPR/Cas9 plasmids into metal-organic frameworks (MOFs) via biomimetic mineralization. The structure-functionality relationship studies indicate that MOF-coated nanostructures dramatically impact the biological features of the contained plasmids through different embedding structures. The plasmids are homogeneously distributed within the heterogeneous nanoarchitecture and protected from enzymatic degradation. In addition, the plasmid-MOF structure exhibits excellent loading capability, pH-responsive release, and affinity for plasmid binding. Through in vitro assays it was found that the superior MOF vector can greatly enhance cellular endocytosis and endo/lysosomal escape of sheltered plasmids, resulting in successful knock-in of GFP-tagged paxillin genomic sequences in cancer cell lines with high transfection potency compared to our previous studies. Thus, the development of new cost-effective approaches for MOF-based intracellular delivery systems offers an attractive option for overcoming the physiological barriers to CRISPR/Cas9 delivery, which shows great potential for investigating paxillin-associated focal adhesions and signal regulation

Integrin endosomal signalling suppresses anoikis

Integrin-containing focal adhesions transmit extracellular signals across the plasma membrane to modulate cell adhesion, signalling and survival. Although integrins are known to undergo continuous endo/exocytic traffic, the potential impact of endocytic traffic on integrin-induced signals is unknown. Here, we demonstrate that integrin signalling is not restricted to cell-ECM adhesions and identify an endosomal signalling platform that supports integrin signalling away from the plasma membrane. We show that active focal adhesion kinase (FAK), an established marker of integrin-ECM downstream signalling, localizes with active integrins on endosomes. Integrin endocytosis positively regulates adhesion-induced FAK activation, which is early endosome antigen-1 and small GTPase Rab21 dependent. FAK binds directly to purified endosomes and becomes activated on them, suggesting a role for endocytosis in enhancing distinct integrin downstream signalling events. Finally, endosomal integrin signalling contributes to cancer-related processes such as anoikis resistance, anchorage independence and metastasis.</p