Prediction of Smoothed Sunspot Number Using Dynamic Relations Between the Sun and Planets

Dynamic parameters of sun and planet interaction for predicting sunspot

Statistical mechanics of ecosystem assembly

We introduce a toy model of ecosystem assembly for which we are able to map out all assembly pathways generated by external invasions. The model allows to display the whole phase space in the form of an assembly graph whose nodes are communities of species and whose directed links are transitions between them induced by invasions. We characterize the process as a finite Markov chain and prove that it exhibits a unique set of recurrent states (the endstate of the process), which is therefore resistant to invasions. This also shows that the endstate is independent on the assembly history. The model shares all features with standard assembly models reported in the literature, with the advantage that all observables can be computed in an exact manner.Comment: Accepted for publication in Physical Review Letter

The Reagan Administration and the AIDS Epidemic: The Relationship Between Rhetoric and Marginalization

The use of rhetoric can be a powerful tool to persuade individuals. Politicians are no stranger to using this tool and often employ it when speaking to their constituents. One politician who utilized his own forms of rhetoric is former President Ronald Reagan. Reagan used rhetoric to discuss major issues with the American public, including the AIDS epidemic. This thesis analyzes Reagan and his administration’s use of rhetoric regarding the AIDS epidemic in order to answer the research question: How did the Reagan administration’s use of rhetoric further marginalize the risk groups associated with the AIDS epidemic? Although previous literature has been published on Reagan’s rhetoric, and many anthropological analyses of rhetoric itself, there is not much literature specifically examining Reagan’s use of rhetoric during the AIDS epidemic. Through the use of coding, I analyzed the instances where rhetoric was used when the Reagan administration spoke about the AIDS epidemic. I found that the Reagan administration often used rhetoric to avoid discussing the complex issues of the epidemic and taking responsibility for stopping the spread of the disease. This, in turn, led to the continued marginalization of AIDS patients and the risk groups associated with the disease. Research on this topic is important because marginalized groups are often scapegoated during times of crisis. This can be seen in recent times with the rise in hate crimes against Asian Americans in response to the spread of COVID-19. My hope is for this thesis to contribute to the existing literature on rhetoric in political discourse and inspire further studies on this subject in order to help eradicate marginalization in our society

Stability as a natural selection mechanism on interacting networks

Biological networks of interacting agents exhibit similar topological properties for a wide range of scales, from cellular to ecological levels, suggesting the existence of a common evolutionary origin. A general evolutionary mechanism based on global stability has been proposed recently [J I Perotti, O V Billoni, F A Tamarit, D R Chialvo, S A Cannas, Phys. Rev. Lett. 103, 108701 (2009)]. This mechanism is incorporated into a model of a growing network of interacting agents in which each new agent's membership in the network is determined by the agent's effect on the network's global stability. We show that, out of this stability constraint, several topological properties observed in biological networks emerge in a self organized manner. The influence of the stability selection mechanism on the dynamics associated to the resulting network is analyzed as well.Comment: 10 pages, 9 figure

Mathematics education research on language and on communication including some distinctions : Where are we now?

Altres ajuts: acords transformatius de la UABIn this article, we present a narrative review of mathematics education research on language and on communication over 2019-2022, but also look ahead by addressing challenges posed by the lack of distinction between language and communication. The persistence and significance of the problem of the distinction between language and communication are thus outlined in a historical moment of celebration of growth of research in the domain. Informed by the analysis of a selection of research journal articles and by our trajectories, we discuss influential topics in the recent discourse: multilingual mathematics classrooms; mathematics teacher education on language in mathematics teaching; multimodal mathematical communication; interaction and mathematics learning; mathematical language and discourse. We connect this with new emerging or old revisited concepts: instructional designing, gesturing, argumenting and languaging. We finish by further reflecting on multimodal mathematical communication and gesturing, and on the potential of expanding the notion of mathematics register towards a notion of mathematics communication register

Tracer les objets à risque dans la documentation des projets spatiaux de longue durée

National audienceCe poster décrit une méthode et un outil permettant de repérer les objets présentés comme " à risque " au début d'un projet spatial dit de longue durée (plus de dix ans) afin de tracer ces objets dans la documentation au cours du projet. L'objectif est de s'assurer que la connaissance concernant la criticité de ces objets n'est pas perdue, en particulier à la fin du projet, lorsque, la sonde ou le satellite étant arrivé(e) à destination, la documentation est à nouveau consultée

Resting respiratory tract dendritic cells preferentially stimulate T helper cell Type 2(Th2) responses and require obligatory cytokine signals for induction of Th1 immunity

Consistent with their role in host defense, mature dendritic cells (DCs) from central lymphoid organs preferentially prime for T helper cell type 1 (Th1)-polarized immunity. However, the “default” T helper response at mucosal surfaces demonstrates Th2 polarity, which is reflected in the cytokine profiles of activated T cells from mucosal lymph nodes. This study on rat respiratory tract DCs (RTDCs) provides an explanation for this paradox. We demonstrate that freshly isolated RTDCs are functionally immature as defined in vitro, being surface major histocompatibility complex (MHC) II lo, endocytosishi, and mixed lymphocyte reactionlo, and these cells produce mRNA encoding interleukin (IL)-10. After ovalbumin (OVA)-pulsing and adoptive transfer, freshly isolated RTDCs preferentially stimulated Th2-dependent OVA-specific immunoglobulin (Ig)G1 responses, and antigen-stimulated splenocytes from recipient animals produced IL-4 in vitro. However, preculture with granulocyte/macrophage colony stimulating factor increased their in vivo IgG priming capacity by 2–3 logs, inducing production of both Th1- and Th2-dependent IgG subclasses and high levels of IFN-γ by antigen-stimulated splenocytes. Associated phenotypic changes included upregulation of surface MHC II and B7 expression and IL-12 p35 mRNA, and downregulation of endocytosis, MHC II processing– associated genes, and IL-10 mRNA expression. Full expression of IL-12 p40 required additional signals, such as tumor necrosis factor α or CD40 ligand. These results suggest that the observed Th2 polarity of the resting mucosal immune system may be an inherent property of the resident DC population, and furthermore that mobilization of Th1 immunity relies absolutely on the provision of appropriate microenvironmental costimuli