146 research outputs found

    Size--sensitive melting characteristics of gallium clusters: Comparison of Experiment and Theory for Ga17+_{17}{}^{+} and Ga20+_{20}{}^{+}

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    Experiments and simulations have been performed to examine the finite-temperature behavior of Ga17+_{17}{}^{+} and Ga20+_{20}{}^{+} clusters. Specific heats and average collision cross sections have been measured as a function of temperature, and the results compared to simulations performed using first principles Density--Functional Molecular--Dynamics. The experimental results show that while Ga17+_{17}{}^{+} apparently undergoes a solid--liquid transition without a significant peak in the specific--heat, Ga20+_{20}{}^{+} melts with a relatively sharp peak. Our analysis of the computational results indicate a strong correlation between the ground--state geometry and the finite--temperature behavior of the cluster. If the ground--state geometry is symmetric and "ordered" the cluster is found to have a distinct peak in the specific--heat. However, if the ground--state geometry is amorphous or "disordered" the cluster melts without a peak in the specific--heat.Comment: 6 figure

    Src Binds Cortactin Through An Sh2 Domain Cystine-Mediated Linkage

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    Tyrosine-kinase-based signal transduction mediated by modular protein domains is critical for cellular function. The Src homology (SH)2 domain is an important conductor of intracellular signaling that binds to phosphorylated tyrosines on acceptor proteins, producing molecular complexes responsible for signal relay. Cortactin is a cytoskeletal protein and tyrosine kinase substrate that regulates actin-based motility through interactions with SH2-domain-containing proteins. The Src kinase SH2 domain mediates cortactin binding and tyrosine phosphorylation, but how Src interacts with cortactin is unknown. Here we demonstrate that Src binds cortactin through cystine bonding between Src C185 in the SH2 domain within the phosphotyrosine binding pocket and cortactin C112/246 in the cortactin repeats domain, independent of tyrosine phosphorylation. Interaction studies show that the presence of reducing agents ablates Src-cortactin binding, eliminates cortactin phosphorylation by Src, and prevents Src SH2 domain binding to cortactin. Tandem MS/MS sequencing demonstrates cystine bond formation between Src C185 and cortactin C112/246. Mutational studies indicate that an intact cystine binding interface is required for Src-mediated cortactin phosphorylation, cell migration, and pre-invadopodia formation. Our results identify a novel phosphotyrosine-independent binding mode between the Src SH2 domain and cortactin. Besides Src, one quarter of all SH2 domains contain cysteines at or near the analogous Src C185 position. This provides a potential alternative mechanism to tyrosine phosphorylation for cysteine-containing SH2 domains to bind cognate ligands that may be widespread in propagating signals regulating diverse cellular functions

    Immanent Justice Reasoning by Spatial Proximity

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    Immanent justice reasoning involves causally attributing someone’s bad outcome to their prior immoral actions. Building on the idea that causality is mentally linked with spatial proximity, we investigated whether such reasoning might lead participants to spatially bind together immoral actions and bad outcomes. Across 4 experiments (N = 553 Mechanical Turk workers), participants positioned sentences describing other people’s bad (vs. good) outcomes closer in space to previous immoral behaviours. This effect was observed both when the position of the initial action remained in a fixed location and when it “chased” the outcome across the screen. Importantly, we also found that this spatial positioning of immoral actions and bad outcomes is mediated by perceived deservingness of the outcome and is not merely due to perceived similarity of events. These findings suggest that perceived deservingness biases the spatial proximity of representations of others’ random bad outcomes and their prior immoral actions

    Evaluating how agent methodologies support the specification of the normative environment through the development process

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    [EN] Due to the increase in collaborative work and the decentralization of processes in many domains, there is an expanding demand for large-scale, flexible and adaptive software systems to support the interactions of people and institutions distributed in heterogeneous environments. Commonly, these software applications should follow specific regulations meaning the actors using them are bound by rights, duties and restrictions. Since this normative environment determines the final design of the software system, it should be considered as an important issue during the design of the system. Some agent-oriented software engineering methodologies deal with the development of normative systems (systems that have a normative environment) by integrating the analysis of the normative environment of a system in the development process. This paper analyses to what extent these methodologies support the analysis and formalisation of the normative environment and highlights some open issues of the topic.This work is partially supported by the PROMETEOII/2013/019, TIN2012-36586-C03-01, FP7-29493, TIN2011-27652-C03-00, CSD2007-00022 projects, and the CASES project within the 7th European Community Framework Program under the grant agreement No 294931.Garcia Marques, ME.; Miles, S.; Luck, M.; Giret Boggino, AS. (2014). Evaluating how agent methodologies support the specification of the normative environment through the development process. Autonomous Agents and Multi-Agent Systems. 1-20. https://doi.org/10.1007/s10458-014-9275-zS120Cossentino, M., Hilaire, V., Molesini, A., & Seidita, V. (Eds.). (2014). Handbook on agent-oriented design processes (Vol. VIII, 569 p. 508 illus.). Berlin: Springer.Akbari, O. (2010). A survey of agent-oriented software engineering paradigm: Towards its industrial acceptance. 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Lecture Notes in Computer Science (Vol. 3913, pp. 99–113). Springer. Berlin.Criado, N., Argente, E., Garrido, A., Gimeno, J. A., Igual, F., Botti, V., Noriega, P., & Giret, A. (2011). Norm enforceability in Electronic Institutions? In Coordination, organizations, institutions, and norms in agent systems VI (Vol. 6541, pp. 250–267). Springer.Dellarocas, C., & Klein, M. (2001). Contractual agent societies. In R. Conte & C. Dellarocas (Eds.), Social order in multiagent systems (Vol. 2, pp. 113–133)., Multiagent Systems, Artificial Societies, and Simulated Organizations New York: Springer.DeLoach, S. A. (2008). Developing a multiagent conference management system using the o-mase process framework. In Proceedings of the international conference on agent-oriented software engineering VIII (pp. 168–181).DeLoach, S. A., & Garcia-Ojeda, J. C. (2010). O-mase; a customisable approach to designing and building complex, adaptive multi-agent systems. International Journal of Agent-Oriented Software Engineering, 4(3), 244–280.DeLoach, S. A., Padgham, L., Perini, A., Susi, A., & Thangarajah, J. (2009). Using three aose toolkits to develop a sample design. International Journal Agent-Oriented Software Engineering, 3, 416–476.Dignum, F., Dignum, V., Thangarajah, J., Padgham, L., & Winikoff, M. (2007). Open agent systems? Eighth international workshop on agent oriented software engineering (AOSE) in AAMAS07.Dignum, V. (2003). A model for organizational interaction:based on agents, founded in logic. PhD thesis, Utrecht University.Dignum, V., Meyer, J., Dignum, F., & Weigand, H. (2003). Formal specification of interaction in agent societies. Formal approaches to agent-based systems (Vol. 2699).Dignum, V., Vazquez-Salceda, J., & Dignum, F. (2005). Omni: Introducing social structure, norms and ontologies into agent organizations. In R. Bordini, M. Dastani, J. Dix, & A. Seghrouchni (Eds.)Programming multi-agent systems. Lecture Notes in Computer Science (Vol. 3346, pp. 181–198). Berlin: Springer.d’Inverno, M., Luck, M., Noriega, P., Rodriguez-Aguilar, J., & Sierra, C. (2012). Communicating open systems, 186, 38–94.Elsenbroich, C., & Gilbert, N. (2014). Agent-based modelling. In Modelling norms (pp. 65–84). Dordrecht: Springer.Esteva, M., Rosell, B., Rodriguez, J. A., & Arcos, J. L. (2004). AMELI: An agent-based middleware for electronic institutions. In AAMAS04 (pp. 236–243).Fenech, S., Pace, G. J., & Schneider, G. (2009). Automatic conflict detection on contracts. In Proceedings of the 6th international colloquium on theoretical aspects of computing, ICTAC ’09 (pp. 200–214).Garbay, C., Badeig, F., & Caelen, J. (2012). Normative multi-agent approach to support collaborative work in distributed tangible environments. In Proceedings of the ACM 2012 conference on computer supported cooperative work companion, CSCW ’12 (pp. 83–86). New York, NY: ACM.Garcia, E., Giret, A., & Botti, V. (2011). Regulated open multi-agent systems based on contracts. In Information Systems Development (pp. 243–255).Garcia, E., Tyson, G., Miles, S., Luck, M., Taweel, A., Staa, T. V., & Delaney, B. (2012). An analysis of agent-oriented engineering of e-health systems. In 13th international eorkshop on sgent-oriented software engineering (AOSE-AAMAS).Garcia, E., Tyson, G., Miles, S., Luck, M., Taweel, A., Staa, T. V., and Delaney, B. (2013). Analysing the Suitability of Multiagent Methodologies for e-Health Systems. In Agent-Oriented Software Engineering XIII, volume 7852, pages 134–150. Springer-Verlag.Garrido, A., Giret, A., Botti, V., & Noriega, P. (2013). mWater, a case study for modeling virtual markets. In New perspectives on agreement technologies (Vol. Law, Gover, pp. 563–579). Springer.Gteau, B., Boissier, O., & Khadraoui, D. (2006). Multi-agent-based support for electronic contracting in virtual enterprises. 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    Vegetative Ecological Characteristics of Restored Reed (Phragmites australis) Wetlands in the Yellow River Delta, China

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    In this study, we compared ecological characteristics of wetland vegetation in a series of restoration projects that were carried out in the wetlands of Yellow River Delta. The investigated characteristics include plant composition structure, species diversity and community similarity in three kinds of Phragmites australis wetlands, i.e. restored P. australis wetlands (R1, R2, R3 and R4: restored in 2002, 2005, 2007 and 2009, respectively), natural P. australis wetland (N) and degraded P. australis wetland (D) to assess the process of wetlands restoration. The coverage of the R1 was 99%, which was similar to natural wetland. Among all studied wetlands, the highest and lowest stem density was observed in R1 and R2, respectively, Plant height and stem diameter show the same trend as N > R2 > R1 > R3 > D > R4. Species diversity of restored P. australis wetlands became closed to natural wetland. Both species richness and Shannon–Wiener index had similar tendency: increased first and then decreased with restored time. The highest species richness and species diversity were observed in R2, while the lowest values of those parameters were found in natural P. australis wetland. Similarity indexes between restored wetlands and natural wetland increased with the restoration time, but they were still less than 50%. The results indicate that the vegetation of P. australis wetlands has experienced a great improvement after several years’ restoration, and it is feasible to restored degraded P. australis wetlands by pouring fresh water into those wetlands in the Yellow River Delta. However, it is notable that costal degraded P. australis wetland in this region may take years to decades to reach the status of natural wetland

    Research in progress: report on the ICAIL 2017 doctoral consortium

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    This paper arose out of the 2017 international conference on AI and law doctoral consortium. There were five students who presented their Ph.D. work, and each of them has contributed a section to this paper. The paper offers a view of what topics are currently engaging students, and shows the diversity of their interests and influences
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