Azelik

Venant de la bourgade de Tegidda n-Tesemt, important carrefour de pistes et passage obligé (du moins jusqu’à la construction récente de la route In Guezzam-Arlit-Agadez) entre Sahara et Sahel, on atteint les sources d’Azelik (département d’Agadez, Niger) par une piste qui, vers le Nord-Est, longe un bombement faillé, surrection au milieu des argilites de l’Eghazer d’un dôme gréseux aplati, faciès intermédiaire, semble-t-il, entre les grès d’Agadez et ceux d’Assaouas. Aux deux extrémités de ce..

New constraints on the location of P9 obtained with the INPOP19a planetary ephemeris

Context. We used the new released INPOP19a planetary ephemerides benefiting from Jupiter-updated positions by the Juno mission and reanalyzed Cassini observations. Aims. We test possible locations of the unknown planet P9. To do this, we used the perturbations it produces on the orbits of the outer planets, more specifically, on the orbit of Saturn. Methods. Two statistical criteria were used to identify possible acceptable locations of P9 according to (i) the difference in planetary positions when P9 is included compared with the propagated covariance matrix, and (ii) the χ2 likelihood of postfit residuals for ephemerides when P9 is included. Results. No significant improvement of the residuals was found for any of the simulated locations, but we provide zones that induce a significant degradation of the ephemerides. Conclusions. Based on the INPOP19a planetary ephemerides, we demonstrate that if P9 exists, it cannot be closer than 500 AU with a 5 M⊕ and no closer than 650 AU with a 10 M⊕ . We also show that there is no clear zone that would indicate the positive existence of planet P9, but there are zones for which the existence of P9 is compatible with the 3σ accuracy of the INPOP planetary ephemerides

Evolution of INPOP planetary ephemerides and Bepi-Colombo simulations

We give here a detailed description of the latest INPOP planetary ephemerides INPOP20a. We test the sensitivity of the Sun oblateness determination obtained with INPOP to different models for the Sun core rotation. We also present new evaluations of possible GRT violations with the PPN parameters $\beta$,$\gamma$ and $\dot{\mu}/\mu$. With a new method for selecting acceptable alternative ephemerides we provide conservative limits of about $7.16 \times 10^{-5}$ and $7.49 \times 10^{-5}$ for $\beta-1$ and $\gamma-1$ respectively using the present day planetary data samples. We also present simulations of Bepi-Colombo range tracking data and their impact on planetary ephemeris construction. We show that the use of future BC range observations should improve these estimates, in particular $\gamma$. Finally, interesting perspectives for the detection of the Sun core rotation seem to be reachable thanks to the BC mission and its accurate range measurements in the GRT frame.Comment: Proceedings of the IAU Symposium 364 "Multi-scale dynamics of space objects

Quantification of the transmural dynamics of atrial fibrillation by simultaneous endocardial and epicardial optical mapping in an acute sheep model

BACKGROUND: Therapy strategies for atrial fibrillation based on electrical characterization are becoming viable personalized medicine approaches to treat a notoriously difficult disease. In light of these approaches that rely on high-density surface mapping, this study aims to evaluate the presence of three-dimensional electrical substrate variations within the transmural wall during acute episodes of atrial fibrillation. METHODS AND RESULTS: Optical signals were simultaneously acquired from the epicardial and endocardial tissue during acute fibrillation in ovine isolated left atria. Dominant frequency, regularity index, propagation angles and phase dynamics were assessed and correlated across imaging planes to gauge the synchrony of the activation patterns compared to paced rhythms. Static frequency parameters were well correlated spatially between the endocardium and the epicardium (dominant frequency, 0.79+/-0.06 and regularity index, 0.93+/-0.009). However, dynamic tracking of propagation vectors and phase singularity trajectories revealed discordant activity across the transmural wall. The absolute value of the difference in the number, spatial stability, and temporal stability of phase singularities between the epicardial and endocardial planes was significantly greater than 0 with a median difference of 1.0, 9.27%, and 19.75%, respectively. The number of wavefronts with respect to time was significantly less correlated and the difference in propagation angle was significantly larger in fibrillation compared to paced rhythms. CONCLUSIONS: Atrial fibrillation substrates are dynamic three-dimensional structures with a range of discordance between the epicardial and endocardial tissue. The results of this study suggest that transmural propagation may play a role in AF maintenance mechanisms

Simplified approach to the application of the geometric collective model

The predictions of the geometric collective model (GCM) for different sets of Hamiltonian parameter values are related by analytic scaling relations. For the quartic truncated form of the GCM -- which describes harmonic oscillator, rotor, deformed gamma-soft, and intermediate transitional structures -- these relations are applied to reduce the effective number of model parameters from four to two. Analytic estimates of the dependence of the model predictions upon these parameters are derived. Numerical predictions over the entire parameter space are compactly summarized in two-dimensional contour plots. The results considerably simplify the application of the GCM, allowing the parameters relevant to a given nucleus to be deduced essentially by inspection. A precomputed mesh of calculations covering this parameter space and an associated computer code for extracting observable values are made available through the Electronic Physics Auxiliary Publication Service. For illustration, the nucleus 102Pd is considered.Comment: RevTeX 4, 15 pages, to be published in Phys. Rev.

A reference architecture for the collaborative planning modelling process in multi-tier supply chain networks: a Zachman-based approach

A prominent and contemporary challenge for supply chain (SC) managers concerns the coordination of the efforts of the nodes of the SC in order to mitigate unpredictable market behaviour and satisfy variable customer demand. A productive response to this challenge is to share pertinent market-related information, on a timely basis, in order to effectively manage the decision-making associated with the SC production and transportation planning processes. This paper analyses the most well-known reference modelling languages and frameworks in the collaborative SC field and proposes a novel reference architecture, based upon the Zachman Framework (ZF), for supporting collaborative plan- ning (CP) in multi-level, SC networks. The architecture is applied to an automotive supply chain configuration, where, under a collaborative and decentralised approach, improvements in the service levels for each node were observed. The architecture was shown to provide the base discipline for the organisation of the processes required to manage the CP activity.The authors thanks the support from the project 'Operations Design and Management in Global Supply Chains (GLOBOP)' (Ref. DPI2012-38061-C02-01), funded by the Ministry of Science and Education of Spain, for the supply chain environment research contribution.Hernández Hormazábal, JE.; Lyons, AC.; Poler, R.; Mula, J.; Goncalves, R. (2014). A reference architecture for the collaborative planning modelling process in multi-tier supply chain networks: a Zachman-based approach. Production Planning and Control. 25(13-14):1118-1134. https://doi.org/10.1080/09537287.2013.808842S111811342513-14Al-Mutawah, K., Lee, V., & Cheung, Y. (2008). A new multi-agent system framework for tacit knowledge management in manufacturing supply chains. Journal of Intelligent Manufacturing, 20(5), 593-610. doi:10.1007/s10845-008-0142-0Baïna, S., Panetto, H., & Morel, G. (2009). New paradigms for a product oriented modelling: Case study for traceability. Computers in Industry, 60(3), 172-183. doi:10.1016/j.compind.2008.12.004Berasategi, L., Arana, J., & Castellano, E. (2011). A comprehensive framework for collaborative networked innovation. Production Planning & Control, 22(5-6), 581-593. doi:10.1080/09537287.2010.536628Chan, H. K., & Chan, F. T. S. (2009). A review of coordination studies in the context of supply chain dynamics. International Journal of Production Research, 48(10), 2793-2819. doi:10.1080/00207540902791843Chen, D., Doumeingts, G., & Vernadat, F. (2008). Architectures for enterprise integration and interoperability: Past, present and future. Computers in Industry, 59(7), 647-659. doi:10.1016/j.compind.2007.12.016Choi, Y., Kang, D., Chae, H., & Kim, K. (2006). An enterprise architecture framework for collaboration of virtual enterprise chains. The International Journal of Advanced Manufacturing Technology, 35(11-12), 1065-1078. doi:10.1007/s00170-006-0789-7Choi, Y., Kim, K., & Kim, C. (2005). A design chain collaboration framework using reference models. The International Journal of Advanced Manufacturing Technology, 26(1-2), 183-190. doi:10.1007/s00170-004-2262-9COLQUHOUN, G. J., BAINES, R. W., & CROSSLEY, R. (1993). A state of the art review of IDEFO. International Journal of Computer Integrated Manufacturing, 6(4), 252-264. doi:10.1080/09511929308944576Danilovic, M., & Winroth, M. (2005). A tentative framework for analyzing integration in collaborative manufacturing network settings: a case study. Journal of Engineering and Technology Management, 22(1-2), 141-158. doi:10.1016/j.jengtecman.2004.11.008Derrouiche, R., Neubert, G., Bouras, A., & Savino, M. (2010). B2B relationship management: a framework to explore the impact of collaboration. Production Planning & Control, 21(6), 528-546. doi:10.1080/09537287.2010.488932Dudek, G., & Stadtler, H. (2005). Negotiation-based collaborative planning between supply chains partners. European Journal of Operational Research, 163(3), 668-687. doi:10.1016/j.ejor.2004.01.014Gruat La Forme, F.-A., Genoulaz, V. B., & Campagne, J.-P. (2007). A framework to analyse collaborative performance. Computers in Industry, 58(7), 687-697. doi:10.1016/j.compind.2007.05.007Gutiérrez Vela, F. L., Isla Montes, J. L., Paderewski Rodríguez, P., Sánchez Román, M., & Jiménez Valverde, B. (2007). An architecture for access control management in collaborative enterprise systems based on organization models. Science of Computer Programming, 66(1), 44-59. doi:10.1016/j.scico.2006.10.005Hernández, J. E., Poler, R., Mula, J., & Lario, F. C. (2010). The Reverse Logistic Process of an Automobile Supply Chain Network Supported by a Collaborative Decision-Making Model. Group Decision and Negotiation, 20(1), 79-114. doi:10.1007/s10726-010-9205-7Hernández, J. E., J. Mula, R. Poler, and A. C. Lyons. 2013. “Collaborative Planning in Multi-Tier Supply Chains Supported by a Negotiation-Based Mechanism and Multi-Agent System.”Group Decision and Negotiation Journal. doi:10.1007/s10726-013-9358-2.Jardim-Goncalves, R., Grilo, A., Agostinho, C., Lampathaki, F., & Charalabidis, Y. (2013). Systematisation of Interoperability Body of Knowledge: the foundation for Enterprise Interoperability as a science. Enterprise Information Systems, 7(1), 7-32. doi:10.1080/17517575.2012.684401Kampstra, R. P., Ashayeri, J., & Gattorna, J. L. (2006). Realities of supply chain collaboration. The International Journal of Logistics Management, 17(3), 312-330. doi:10.1108/09574090610717509Kim, W., Chung, M. J., Qureshi, K., & Choi, Y. K. (2006). WSCPC: An architecture using semantic web services for collaborative product commerce. Computers in Industry, 57(8-9), 787-796. doi:10.1016/j.compind.2006.04.007Ku, K.-C., Kao, H.-P., & Gurumurthy, C. K. (2007). Virtual inter-firm collaborative framework—An IC foundry merger/acquisition project. Technovation, 27(6-7), 388-401. doi:10.1016/j.technovation.2007.02.010LEE, J., GRUNINGER, M., JIN, Y., MALONE, T., TATE, A., YOST, G., & OTHER MEMBERS OF THE PIF WORKING GROUP. (1998). The Process Interchange Format and Framework. The Knowledge Engineering Review, 13(1), 91-120. doi:10.1017/s0269888998001015Lee, J., Chae, H., Kim, C.-H., & Kim, K. (2009). Design of product ontology architecture for collaborative enterprises. Expert Systems with Applications, 36(2), 2300-2309. doi:10.1016/j.eswa.2007.12.042Liu, J., Zhang, S., & Hu, J. (2005). A case study of an inter-enterprise workflow-supported supply chain management system. Information & Management, 42(3), 441-454. doi:10.1016/j.im.2004.01.010Marques, D. M. N., & Guerrini, F. M. (2011). Reference model for implementing an MRP system in a highly diverse component and seasonal lean production environment. Production Planning & Control, 23(8), 609-623. doi:10.1080/09537287.2011.572469Mula, J., Peidro, D., & Poler, R. (2010). The effectiveness of a fuzzy mathematical programming approach for supply chain production planning with fuzzy demand. International Journal of Production Economics, 128(1), 136-143. doi:10.1016/j.ijpe.2010.06.007Murata, T. (1989). Petri nets: Properties, analysis and applications. Proceedings of the IEEE, 77(4), 541-580. doi:10.1109/5.24143Noran, O. (2003). An analysis of the Zachman framework for enterprise architecture from the GERAM perspective. Annual Reviews in Control, 27(2), 163-183. doi:10.1016/j.arcontrol.2003.09.002Olorunniwo, F. O., & Li, X. (2010). Information sharing and collaboration practices in reverse logistics. Supply Chain Management: An International Journal, 15(6), 454-462. doi:10.1108/13598541011080437Recker, J., Rosemann, M., Indulska, M., … Green, P. (2009). Business Process Modeling- A Comparative Analysis. Journal of the Association for Information Systems, 10(04), 333-363. doi:10.17705/1jais.00193Rodriguez, K., & Al-Ashaab, A. (2005). Knowledge web-based system architecture for collaborative product development. Computers in Industry, 56(1), 125-140. doi:10.1016/j.compind.2004.07.004Romero, F., Company, P., Agost, M.-J., & Vila, C. (2008). Activity modelling in a collaborative ceramic tile design chain: an enhanced IDEF0 approach. Research in Engineering Design, 19(1), 1-20. doi:10.1007/s00163-007-0040-zSandberg, E. (2007). Logistics collaboration in supply chains: practice vs. theory. The International Journal of Logistics Management, 18(2), 274-293. doi:10.1108/09574090710816977Spekman, R. E., & Carraway, R. (2006). Making the transition to collaborative buyer–seller relationships: An emerging framework. Industrial Marketing Management, 35(1), 10-19. doi:10.1016/j.indmarman.2005.07.002Stevens, W. P., Myers, G. J., & Constantine, L. L. (1974). Structured design. IBM Systems Journal, 13(2), 115-139. doi:10.1147/sj.132.0115Ulieru, M. (2000). A multi-resolution collaborative architecture for web-centric global manufacturing. Information Sciences, 127(1-2), 3-21. doi:10.1016/s0020-0255(00)00026-8Van der Aalst, W. M. P. (1999). Formalization and verification of event-driven process chains. Information and Software Technology, 41(10), 639-650. doi:10.1016/s0950-5849(99)00016-6Zachman, J. A. (1987). A framework for information systems architecture. IBM Systems Journal, 26(3), 276-292. doi:10.1147/sj.263.0276Zapp, M., Forster, C., Verl, A., & Bauernhansl, T. (2012). A Reference Model for Collaborative Capacity Planning Between Automotive and Semiconductor Industry. Procedia CIRP, 3, 155-160. doi:10.1016/j.procir.2012.07.028Zeng, Y., Wang, L., Deng, X., Cao, X., & Khundker, N. (2012). Secure collaboration in global design and supply chain environment: Problem analysis and literature review. Computers in Industry, 63(6), 545-556. doi:10.1016/j.compind.2012.05.00

Proarrhythmic remodelling of the right ventricle in a porcine model of repaired tetralogy of Fallot

OBJECTIVE: The growing adult population with surgically corrected tetralogy of Fallot (TOF) is at risk of arrhythmias and sudden cardiac death. We sought to investigate the contribution of right ventricular (RV) structural and electrophysiological remodelling to arrhythmia generation in a preclinical animal model of repaired TOF (rTOF). METHODS AND RESULTS: Pigs mimicking rTOF underwent cardiac MRI functional characterisation and presented with pulmonary regurgitation, RV hypertrophy, dilatation and dysfunction compared with Sham-operated animals (Sham). Optical mapping of rTOF RV-perfused wedges revealed a significant prolongation of RV activation time with slower conduction velocities and regions of conduction slowing well beyond the surgical scar. A reduced protein expression and lateralisation of Connexin-43 were identified in rTOF RVs. A remodelling of extracellular matrix-related gene expression and an increase in collagen content that correlated with prolonged RV activation time were also found in these animals. RV action potential duration (APD) was prolonged in the epicardial anterior region at early and late repolarisation level, thus contributing to a greater APD heterogeneity and to altered transmural and anteroposterior APD gradients in rTOF RVs. APD remodelling involved changes in Kv4.3 and MiRP1 expression. Spontaneous arrhythmias were more frequent in rTOF wedges and more complex in the anterior than in the posterior RV. CONCLUSION: Significant remodelling of RV conduction and repolarisation properties was found in pigs with rTOF. This remodelling generates a proarrhythmic substrate likely to facilitate re-entries and to contribute to sudden cardiac death in patients with rTOF

Analytically Solvable Asymptotic Model of Atrial Excitability

We report a three-variable simplified model of excitation fronts in human atrial tissue. The model is derived by novel asymptotic techniques \new{from the biophysically realistic model of Courtemanche et al (1998) in extension of our previous similar models. An iterative analytical solution of the model is presented which is in excellent quantitative agreement with the realistic model. It opens new possibilities for analytical studies as well as for efficient numerical simulation of this and other cardiac models of similar structure