Nash Equilibrium and information transmission coding and decoding rules

The design of equilibrium protocols in sender-receiver games where communication is noisy occupies an important place in the Economic literature. This paper shows that the common way of constructing a noisy channel communication protocol in Information Theory does not necessarily lead to a Nash equilibrium. Given the decoding scheme, it may happen that, given some state, it is better for the sender to transmit a message that is different from that prescribed by the codebook. Similarly, when the sender uses the codebook as prescribed, the receiver may sometimes prefer to deviate from the decoding scheme when receiving a message.Noisy channel, Shannon's Theorem, sender-receiver games, Nash equilibrium

Pragmatic Languages with Universal Grammars

This paper shows the existence of an equilibrium pragmatic Language with a universal grammar as a coordination device under communication misunderstandings. Such a language plays a key role in achieving efficient outcomes in those Sender-Receiver games where there may exist noisy information transmission. The Language is pragmatic in the sense that the Receiver’ best response depends on the context, i.e, on the payoffs and on the initial probability distribution of the states of nature of the underlying game. The Language has a universal grammar because the coding rule does not depend on such specific parameters and can then be applied to any Sender-Receiver game with noisy communication.grammar, pragmatic language, prototypes, separating equilibria

Neotectonic deformations in the fluvial relief of the Llanura Sur of Pinar del Río, Cuba

Las investigaciones neotectónicas se enfocan a la determinación de los movimientos tectónicos más recientes de la corteza terrestre y poseen un gran significado en el análisis geomorfológico de la estructura del relieve moderno. En las regiones relativamente llanas no siempre resulta fácil el reconocimiento de evidencias de las deformaciones neotectónicas en el relieve fluvial. Desde el punto de vista metodológico, quedó demostrada la eficiencia del empleo de los métodos geológicos, geomorfológicos y edafológicos, como la evaluación morfométrica del relieve, el análisis de anomalías del drenaje, el estudio de la distribución espacial de los complejos estratigráficos y de los sedimentos aluviales, y la espectrometría del canal de potasio en los mismos. Sus resultados destacaron la existencia de bloques longitudinales de tipo horst y graben, corroborando los resultados geofísicos y de perforaciones, así como la identificación de tres bloques transversales escalonados, de oeste a este, con amplitudes diferenciadas de los desplazamientos verticales del orden de 6 y 10 m. Los bloques centro-orientales (II y III) han experimentado una basculación tectónica sostenida, forzando la migración de la red fluvial en dirección suroeste, como lo evidencia la asimetría de las cuencas hidrográficas y la migración de los ríos en esa dirección. Finalmente, se pudo establecer que los ríos, en la parte axial de la llanura, muestran un patrón regional de inflexión horaria de sus cauces, asociado probablemente a movimientos neotectónicos decizalladura que se manifiestan a lo largo de la dislocación que constituye el límite meridional de la depresión Los Palacios

Effects of Hydrogen Bonding and Molecular Chain Flexibility of Substituted n-Alkyldimethylsilanes On Impact Ice Adhesion Shear Strength

The effects of hydrogen bonding and molecular flexibility upon ice adhesion shear strength were investigated using aluminum substrates coated with substituted n-alkyldimethylalkoxysilanes. The location of the chemical group substitution was on the opposing end of the linear n-alkyl chain with respect to silicon. Three hydrogen-bonding characteristics were evaluated: 1) non-hydrogen bonding, 2) donor/acceptor, and 3) acceptor. Varying the length of the n-alkyl chain provided an assessment of molecular chain flexibility. Coated and uncoated aluminum surfaces were characterized by receding water contact angle and surface roughness. Ice adhesion shear strength was determined in the Adverse Environment Rotor Test Stand facility from -16 to -8C that simulated aircraft in-flight icing conditions within the FAR Part 25/29 Appendix C icing envelope. Surface roughness of the coatings was similar allowing for comparison of the test results. An adhesion reduction factor, based on the ice adhesion shear strength data with respect to uncoated aluminum obtained at the same temperature, was calculated to compare the data. The results revealed complex interactions with impacting supercooled water droplets that were interdependent upon ice accretion temperature, surface energy characteristics of water and ice, hydrogen bonding characteristic of the substituent, and length of the n-alkyl chain. To aid in explaining the results, 1) changes in the surface energy component (i.e., non-polar and polar) values that water undergoes during its phase change from liquid to solid that arise from the freezing of impacting supercooled water droplets on the surface depended upon the temperature during accretion were taken into account and 2) the physical properties (i.e., water solubility and melting point) of small compounds analogous to the substituted n-alkyldimethylalkoxysilanes used in this study were compared

Temperature and particle concentration influence on the complex viscous behavior of a hydrophilic fumed silica suspension

Shear-thinning behavior (decrease of the apparent steady viscosity with shear) due to breaking of weak particle flocs and posterior alignment of individual particles in layers parallel to the flow direction is usually observed before the appearance of the shear-thickening behavior (increase of the apparent steady viscosity with shear). The shear-thickening behavior is mainly due to the dominant role played by hydrodynamic over Brownian and colloidal forces at relatively high shear. As a rule, the onset of shear-thickening behavior and the maximum viscosity value appear at lower shear rates when solid concentration increases, and temperature decreases. However, the influence of solid concentration and temperature on shear stress characteristic values have received less attention despite being the shear stress the true cause of microstructure changes that can provoke the appearance of the shear-thickening behaviour. A recently published empirical equation for the shear stress dependence of the steady viscosity of shear thickening fluids [T. Shende, V.J. Niasar, M. Babaei, J. Mol. Liq. 325 (2021) 115220] has been used for fitting experimental data (MARSIII, Thermo-Haake, Germany) of a hydrophilic fumed silica suspension (A200 (Evonik, Germany) in PPG400 (Sigma-Aldrich, Germany)). The influence of temperature (10,\ 30,\ 50,\ 70\degc) and solid concentration (10,\ 15,\ 20,\ 25%\ wt) on the shear-thickening behavior has been monitored recording their influence on the model parameters.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Dependence estimation and controlled CVaR portfolio optimization of a highly kurtotic Australian mining sample of stocks

The drivers of mining stock prices are known to be several. Sharp spikes on the stocks return distribution have been linked to the presence of unusually high volatility signifying the presence of high levels of kurtosis. The accurate measurement of the stocks’ underlying co-movements for more accurate CVaR portfolio optimization requires, therefore, the utilization of sophisticated and specific-specialized techniques which could adequately capture and model these characteristics. Here this issue is addressed by applying statistical-graphical models for dependence estimation. Twenty mining stocks, out of the 801 listed in the ASX as of December 2012, have been selected for the analysis under the criteria of satisfying the eight years trading period sought, having very weak or no autocorrelation of residuals and displaying the highest kurtosis. Models’ estimations of dependence are compared and inserted into a differential evolution algorithm for non-convex global optimization in order to conduct risk controlled CVaR portfolio optimization (Ardia, Boudt, Carl, Mullen & Peterson, 2011) and be able to identify the one yielding the highest portfolio return. The findings are of relevance in portfolio allocation and portfolio risk management. Energy and mining stock markets are subjected to numerous price drivers holding complex relationships. The dynamics of production and consumption based on seasonality features, transportation and storage, weather conditions, commodity price fluctuations, currency changes, market confidence and expectations, trading speculations and the domestic and international states of the economy impact mining stock prices in particular and unobvious ways reflected in high volatility with sudden spikes in the stock’s return distribution (Pilipovic, 1998). The generation of accurate measurements of the dependence matrix of mining stock’s return series is therefore both, a non-trivial task due to the hard to decipher characteristics present in return series suffering from high levels of kurtosis (Carvalho, Lopes & Aguilar, 2010) and, a crucial element in portfolio optimization and portfolio risk management. The use of graphical techniques in this study is justified on the basis of their utility and suitableness. Graphical models such as pair c-vine copulas, the graphical lasso and adaptive graphical lasso provide, for instance, the visualization and flexibility to represent a problem in a more simplified and dissected form (Lauritzen, 1996). Graphs also appear to be naturally adequate to express the interaction of variables and thus facilitate the analysis of their dependency. The models of dependence estimation and CVaR portfolio optimization, on the other hand, are desirable due to mathematical and statistical framework they provide which may lead to satisfactory results and, their apparent ability to overcome the flaws (i.e. standardized model application to all joint distributions, restrictive and deterministic linear and monotonic modelling functions as in the Pearson and Spearman) traditional measures display when dealing with highly kurtotic data, joint distributions with stronger dependence in the tails and controlled risk non-convex portfolio optimization problems. Findings indicate that the highest portfolio returns are generated by inserting the covariance output matrix from the student-t copula into the differential optimization algorithm and, the student-t copula fitting with separate modelling of the marginal distributions appears to be the most desirable modelling choice. The portfolio return by the adaptive graphical lasso is lower than that of the student-t and is followed by the Gaussian pair c-vine copula. The regular graphical lasso produced the lowest portfolio return and the covariance matrix values were higher for models producing the highest portfolio returns implying that the models generating the lowest portfolio returns underestimated the dependence of the assets. The implications of the findings suggest that specific modelling of each marginal distribution, as compared to modelling based on a Gaussian framework, may lead to an edge in the estimations due to the distribution differences encountered on each marginal. Furthermore, the ability of the model to capture dependence in the tails, as it is the case of the student-t copula, does provide a modelling advantage too. This paper appears to be the first one in, comparing the portfolio performance of the models of dependence estimation in the context of controlled CVaR, applying the models treated to a highly kurtotic mining sample of stocks from the Australian market and modelling separately the distribution of the marginals when fitting the student-t copula

The Internationalization of Mexican Fisheries Companies and the Rise of Theire Exports to the Italian Market

Opening up trade under the guidelines of trade agreements is presented as an area of opportunity for Mexico to diversify markets.Reality demonstrates that U.S. and Mexico hold a large concentration of commercial transactions. In the case of fishery products, the European Union, particularly the Italian market is presented as a great potential to achieve this market diversification. Therefore, in this research the characteristics of the European market are analyzed. Their purchasing power and the advantages and disadvantages for Mexican exports, particularly those derived from fishery products.Keywords. Trade Agreements, International Business, EU, Markets.JEL. F13, F23, F15, D47

Systematic review and meta-analysis of secondary prophylaxis for prevention of HIV-related toxoplasmic encephalitis relapse using trimethoprim-sulfamethoxazole

A recent systematic literature and meta-analysis reported relative efficacy of trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of toxoplasmic encephalitis (TE) in HIV-infected adults. Here, we estimated relapse rates during secondary prophylaxis with TMP-SMX, and further explored differences in relapse rates prior to introduction of highly active antiretroviral therapy (HAART) and the widespread adoption of HAART. A systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials yielded 707 studies whereby 663 were excluded after abstract screening, and 38 were excluded after full review leaving 6 studies for extraction. We performed double data extraction with a third-party adjudicator. Study designs varied with only one randomized study, four prospective cohorts and one retrospective cohort. Relapse rates were transformed using the Freeman-Tukey method and pooled using both fixed-effect and random-effects meta-analysis models. The TMP-SMX relapse rate was 16.4% (95% CI = 6.2% to 30.3%) based on random-effects models. When the disaggregated pre-HAART studies (n = 4) were included, the relapse rate was 14.9% (random effects; 95% CI = 3.7% to 31.9%). Analysis of two post-HAART studies indicated a relapse rate of 19.2% (random effects; 95% CI = 2.8% to 45.6%). Comparing the relapse rates between pre- and post-HAART studies were contrary to what might be expected based on known benefits of HAART therapy in this population. Nevertheless, cautious interpretation is necessary considering the heterogeneity of the included studies and a limited number of subjects receiving TMP-SMX reported in the post-HAART era.Revisión por pare

Integral Field Spectroscopy of the inner kpc of the elliptical galaxy NGC 5044

We used Gemini Multi-Object Spectrograph (GMOS) in the Integral Field Unit mode to map the stellar population, emission line flux distributions and gas kinematics in the inner kpc of NGC 5044. From the stellar populations synthesis we found that the continuum emission is dominated by old high metallicity stars ($\sim$13 Gyr, 2.5Z$\odot$). Also, its nuclear emission is diluted by a non thermal emission, which we attribute to the presence of a weak active galactic nuclei (AGN). In addition, we report for the first time a broad component (FWHM$\sim$ 3000km$s^{-1}$) in the H$\alpha$ emission line in the nuclear region of NGC 5044. By using emission line ratio diagnostic diagrams we found that two dominant ionization processes coexist, while the nuclear region (inner 200 pc) is ionized by a low luminosity AGN, the filamentary structures are consistent with being excited by shocks. The H$\alpha$ velocity field shows evidence of a rotating disk, which has a velocity amplitude of $\sim$240kms$^{-1}$ at $\sim$ 136 pc from the nucleus. Assuming a Keplerian approach we estimated that the mass inside this radius is $1.9\times10^9$ $M_{\odot}$, which is in agreement with the value obtained through the M-$\sigma$ relation, $M_{SMBH}=1.8\pm1.6\times10^{9}M_{\odot}$. Modelling the ionized gas velocity field by a rotating disk component plus inflows towards the nucleus along filamentary structures, we obtain a mass inflow rate of $\sim$0.4 M$_\odot$. This inflow rate is enough to power the central AGN in NGC 5044.Comment: 16 pages, 12 figures, accepted by MNRA