AN EXPERIMENTAL INVESTIGATION OF GASEOUS-FILM COOLING OF A ROCKET MOTOR

Gaseous-film cooling of rocket combustion chambe

Using deuterated H3+ and other molecular species to understand the formation of stars and planets

The H3+ ion plays a key role in the chemistry of dense interstellar gas clouds where stars and planets are forming. The low temperatures and high extinctions of such clouds make direct observations of H3+ impossible, but lead to large abundances of H2D+ and D2H+ which are very useful probes of the early stages of star and planet formation. Maps of H2D+ and D2H+ pure rotational line emission toward star-forming regions show that the strong deuteration of H3+ is the result of near-complete molecular depletion of CNO-bearing molecules onto grain surfaces, which quickly disappears as cores warm up after stars have formed. In the warmer parts of interstellar gas clouds, H3+ transfers its proton to other neutrals such as CO and N2, leading to a rich ionic chemistry. The abundances of such species are useful tracers of physical conditions such as the radiation field and the electron fraction. Recent observations of HF line emission toward the Orion Bar imply a high electron fraction, and we suggest that observations of OH+ and H2O+ emission may be used to probe the electron density in the nuclei of external galaxies.Comment: Proceedings of the H3+ centennial symposium, to be published in RSPTA (editor: T. Oka

Distinguishing the opponents in the prisoner dilemma in well-mixed populations

Here we study the effects of adopting different strategies against different opponent instead of adopting the same strategy against all of them in the prisoner dilemma structured in well-mixed populations. We consider an evolutionary process in which strategies that provide reproductive success are imitated and players replace one of their worst interactions by the new one. We set individuals in a well-mixed population so that network reciprocity effect is excluded and we analyze both synchronous and asynchronous updates. As a consequence of the replacement rule, we show that mutual cooperation is never destroyed and the initial fraction of mutual cooperation is a lower bound for the level of cooperation. We show by simulation and mean-field analysis that for synchronous update cooperation dominates while for asynchronous update only cooperations associated to the initial mutual cooperations are maintained. As a side effect of the replacement rule, an "implicit punishment" mechanism comes up in a way that exploitations are always neutralized providing evolutionary stability for cooperation

Statistics of opinion domains of the majority-vote model on a square lattice

The existence of juxtaposed regions of distinct cultures in spite of the fact that people's beliefs have a tendency to become more similar to each other's as the individuals interact repeatedly is a puzzling phenomenon in the social sciences. Here we study an extreme version of the frequency-dependent bias model of social influence in which an individual adopts the opinion shared by the majority of the members of its extended neighborhood, which includes the individual itself. This is a variant of the majority-vote model in which the individual retains its opinion in case there is a tie among the neighbors' opinions. We assume that the individuals are fixed in the sites of a square lattice of linear size $L$ and that they interact with their nearest neighbors only. Within a mean-field framework, we derive the equations of motion for the density of individuals adopting a particular opinion in the single-site and pair approximations. Although the single-site approximation predicts a single opinion domain that takes over the entire lattice, the pair approximation yields a qualitatively correct picture with the coexistence of different opinion domains and a strong dependence on the initial conditions. Extensive Monte Carlo simulations indicate the existence of a rich distribution of opinion domains or clusters, the number of which grows with $L^2$ whereas the size of the largest cluster grows with $\ln L^2$. The analysis of the sizes of the opinion domains shows that they obey a power-law distribution for not too large sizes but that they are exponentially distributed in the limit of very large clusters. In addition, similarly to other well-known social influence model -- Axelrod's model -- we found that these opinion domains are unstable to the effect of a thermal-like noise

A Submillimeter HCN Laser in IRC+10216

We report the detection of a strong submillimeter wavelength HCN laser line at a frequency near 805 GHz toward the carbon star IRC+10216. This line, the J=9-8 rotational transition within the (04(0)0) vibrationally excited state, is one of a series of HCN laser lines that were first detected in the laboratory in the early days of laser spectroscopy. Since its lower energy level is 4200 K above the ground state, the laser emission must arise from the inner part of IRC+10216's circumstellar envelope. To better characterize this environment, we observed other, thermally emitting, vibrationally excited HCN lines and find that they, like the laser line, arise in a region of temperature approximately 1000 K that is located within the dust formation radius; this conclusion is supported by the linewidth of the laser. The (04(0)0), J=9-8 laser might be chemically pumped and may be the only known laser (or maser) that is excited both in the laboratory and in space by a similar mechanism.Comment: 11 pages, 3 figure

Euroescepticismo en el Parlamento Europeo: un estudio de la actuación euroescéptica en las elecciones europeas (2009-2019)

This paper analyses the progression of eurosceptic groups within the European Parliament between 2009 and 2019. Through pre-established definitions of Euroscepticism as a political phenomenon, we conduct a quantitative and qualitative analysis, which gathers data from the official results of 3 European legislative elections (2009, 2014 and 2019) and later interprets them with the aid of previous academic production on eurosceptic values and strategies within the European Union’s institutions. As a conclusion, we seek to demonstrate that Euroscepticism is a consequence of a greater scenario, which relates to a gradual loss of public trust in the European political establishment.Este trabajo analiza la progresión de los grupos euroescépticos en el Parlamento Europeo entre 2009 y 2019. A través de definiciones preestablecidas del Euroescepticismo como fenómeno político, hacemos un análisis cuantitativo y cualitativo que recopila datos de los resultados oficiales de 3 elecciones legislativas europeas (2009, 2014 y 2019) y que luego los interpreta con el auxilio de la producción académica previa sobre los valores y estrategias euroescépticas en las instituciones de la Unión Europea. Como conclusión, buscamos demostrar que el Euroescepticismo es una consecuencia de un contexto mayor, el cual se relaciona a una pérdida gradual de confianza pública en el establecimiento político europeo.Instituto de Relaciones Internacionale

Quasi-Lie schemes and Emden--Fowler equations

The recently developed theory of quasi-Lie schemes is studied and applied to investigate several equations of Emden type and a scheme to deal with them and some of their generalisations is given. As a first result we obtain t-dependent constants of the motion for particular instances of Emden equations by means of some of their particular solutions. Previously known results are recovered from this new perspective. Finally some t-dependent constants of the motion for equations of Emden type satisfying certain conditions are recovered

Observatório de Democracias

VII Seminário de Extensão Universitária da UNILA (SEUNI); VIII Encontro de Iniciação Científica e IV Encontro de Iniciação em Desenvolvimento Tecnológico e Inovação (EICTI 2019) e Seminário de Atividades Formativas da UNILA (SAFOR)O projeto Observatório de Democracias tem como objetivo prover dados sistematizados e atualizados sobre democracia e observação eleitoral no MERCOSUL, além de fornecer análises sobre a temática, permitindo que os cidadãos e os decisores dos países do bloco disponham de informações qualificadas para adotar decisões relacionadas às políticas públicas ligadas à democraciaO projeto Observatório de Democracias agradece solenemente a Universidade Federal da Integração Latino Americana (UNILA), especialmente a pró reitoria de extensão (PROEX), por financiar o projeto e fazer possível essa propost