Exchange Volatility and Risk Premium

This paper empirically evaluates the importance of exchange rate regimes and exchange rate volatility on interest rate differentials, with special reference to Chile. We estimate risk-premia for 16 country experiences with different exchange rate regimes and then investigate whether these premia vary with volatility and the regime flexibility. When we assume that any diversifiable risk is actually traded and estimate a CAPM model augmented by taxes, we find a systematic but small relation between exchange rate volatility and risk-premium. In the case of Chile we do not find any significant impact of changes in exchange rate volatility on CAPM-estimated risk-premium. However, when we consider the overall effect of volatility on risk-premium and estimate an ARCH-M model we find a large effect of volatility on risk-premium in this country. In this set-up, when we analyze the cross-country experience, we do not find any relation between regime flexibility and risk-premium.

BTX abatement using Chilean natural zeolite: the role of Brønsted acid sites

In wastewater treatment facilities, air quality is not only affected by conventional unpleasant odour compounds; toxic volatile organic compounds (VOCs) are also found. In this study, the adsorptive capacity of Chilean natural zeolite toward VOC removal was evaluated. Moreover, the influence of zeolite chemical surface properties on VOC elimination was also investigated. Three modified zeolite samples were prepared from a natural Chilean zeolite (53% clinoptilolite, 40% mordenite and 7% quartz). Natural and modified zeolite samples were characterised by nitrogen adsorption at 77 K, elemental analyses and X-ray fluorescence (XRF). Chemical modifications of natural zeolite showed the important role of Brønsted acid sites on the abatement of VOCs. The presence of humidity has a negative effect on zeolite adsorption capacity. Natural zeolites could be an interesting option for benzene, toluene and xylene vapour emission abatement

A Framework for Printing and Minting Plans

This paper presents alternative models for forecasting the demand for bills and coins of different denominations. When compared to the models often used, the root mean squared forecasting error is substantially reduced. The paper also develops a new framework to formulate the printing and minting programs by using density forecasts along with information on technological constraints and preferences of the policy maker.

Residualidad de aplicaciones consecutivas de atrazina en un suelo franco-arcilloso, y su efecto sobre el establecimiento y crecimiento de brocoli, lechuga y ajo.

Resumen (Spanish, English)53 p.Se evaluó el efecto de aplicaciones consecutivas de atrazina en un suelo franco-arcilloso de la zona de Talca sobre el establecimiento y crecimiento de tres especies hortícolas de otoño-invierno: brócoli cv. Legacy, ajo rosado y lechuga cv. Floresta. Se realizaron tres experimentos en el Campus Lircay (35° 30´ LS; 71° 41´ LW; 90 m.s.n.m.) y Estación Experimental Panguilemo (35° 26´ LS; 71° 41´ LW; 90 m.s.n.m.) pertenecientes a la Universidad de Talca. El transplante se efectuó en otoño de 1997 en invernadero, en suelos extraídos de sectores con 1, 2, 3, 4 y 5 aplicaciones consecutivas de atrazina en años anteriores, más un testigo sin aplicación. Estos experimentos también eran establecidos en el campo en los sectores con 5 años de atrazina y el sector sin aplicación. Se evaluó la población presente 25 y 40 días pos-transplante, crecimiento aéreo y radical, área foliar por planta y posible retraso del desarrollo. Se observó un alto porcentaje de establecimiento que superó el 87 % en todos los cultivos, en invernadero como en campo. Ajo y brócoli fueron los cultivos más tolerantes no siendo afectados su crecimiento aéreo y radical en ningún suelo. Lechuga se vio afectada en el suelo con 5 aplicaciones de atrazina debido a la existencia de residuos provenientes de la tempotrada anterior cuando el suelo se mantuvo en barbecho después de la aplicación del herbicida. No se observaron indicios de una acumulación de atrazina con el aumento progresivo de años con utilización de este compuesto

Evaluation in vitro of proliferative activity of epithelial cells by flavonoid 3-O-methylgalangine and terpenenic derivative Filifolinone

The skin is the largest organ of the human body and its main function is to protect it from the external environment. It is exposed to injuries that require a rapid healing process to recover its functionality. Microorganisms inhabit the skin, which makes up the normal microbial flora, but in situations of injury they can cause infections that slow down the regeneration process. Therefore, there is a great interest in the development of alternative methods to accelerate the regeneration process and prevent infections. In this work, the efficacy of flavonoid 3-O-methylgalangine and the terpenic derivative Filifolinone and its mixtures, isolated from plants of the genus Heliotropium, on the stimulation of cell proliferation was evaluated. The results showed that the mixtures stimulated proliferation and migration in MA104 cells mainly due to the presence of Filifolinone, that together with the known antibacterial activity of 3-O-methylgalangine, opens new alternatives for the use of natural compounds in healing processes

SARS-CoV-2 and its Metaphors

The current SARS-CoV-2 pandemic has brought, as in past pandemics, a series of metaphors and, still, a recent literature about it. In addition to philosophical and economic questions, that have caused an unprecedented crisis and that it is early to evaluate with a proper perspective.La pandemia actual de SARS-CoV-2 ha traído, como en pandemias pasadas, una serie de metáforas y literatura todavía aún reciente en torno a la misma. Además de cuestiones filosóficas y económicas, que han provocado una crisis sin precedente y que es pronto para evaluar con una perspectiva adecuada

Jogos de vídeo e aprendizagem de inglês: um estudo exploratório das percepções dos professores de pré-serviço de língua inglesa

The present study explores the knowledge and perceptions that 72 Chilean EFL (English as a foreign language) pre-service teachers have regarding the effect of video games in their daily and academic routine in terms of foreign language learning. By applying a 5-point Likert scale, it was possible to gather data concerning their sociodemographic characteristics and their views in relation to five dimensions: (1) Generalexperience with video games, (2) general preferences about video games, (3) strengths and weaknesses of video games, (4) video games as a learning experience, and (5) video games and the four language skills. Once the data were collected, the Spearman’s orrelation coefficient was used with the purpose of determining the relationships among the respondents’ answers. The results indicated that the four language skills, especially the receptive skills, can be practiced while playing video games. Also, digital games allowed the participants to teach and learn from other players through gameplay. This process was followed by a hierarchical cluster analysis that allocated the respondents into four groups based on the similarities of their responses.El presente estudio explora el conocimiento y las percepciones que setenta y dos profesores/as de inglés en formación, de nacionalidad chilena, tienen sobre el efecto de los videojuegos en su vida diaria y estudiantil, en términos del aprendizaje de un idioma extranjero. Al aplicar una escala de Likert de cinco puntos fue posible reunir información concerniente a sus características sociodemográficas y sus puntos de vista con relación a cinco dimensiones: (1) Experiencia general con videojuegos, (2) preferencias generales acerca de los videojuegos, (3) fortalezas y debilidades de los videojuegos, (4) videojuegos como una experiencia de aprendizaje y (5) videojuegos y las cuatro habilidades del idioma. Una vez que los datos fueron recopilados, se aplicó el análisis correlacional de Spearman para identificar relaciones entre las respuestas de los participantes. Se estableció que las cuatro habilidades lingüísticas, especialmente las receptivas, pueden ser practicadas mientras se juegan videojuegos. También, los juegos digitales permitieron a los/as participantes que enseñaran a otros jugadores/ as en línea y aprendieran de ellos/as a través del juego. Este proceso fue seguido de un análisis de conglomerados (cluster) jerárquico que asignó a los/as participantes en cuatro grupos sobre la base de las similitudes de sus respuestas.O presente estudo explora os conhecimentos e percepções que 72 professores chilenos de pré-serviço de língua inglesa têm a respeito do efeito dos jogos de vídeo em sua rotina diária e acadêmica em termos de aprendizagem de línguas estrangeiras. Aplicando uma escala de 5 pontos Likert, foi possível reunir dados relativos às suas características sociodemográficas e seus pontos de vista em relação a cinco dimensões: (1) Experiência geral com jogos de vídeo; (2) Preferências gerais sobre jogos de vídeo; (3) Pontos fortes e fracos dos jogos de vídeo; (4) Jogos de vídeo como uma experiência de aprendizagem; e (5) Os videogames e as quatro habilidades linguísticas. Uma vez coletados os dados, foi aplicada uma análise de correlação Spearman com o objetivo de determinar as relações entre as respostas dos entrevistados. Os resultados indicaram que as quatro habilidades linguísticas, especialmente as habilidades receptivas, podem ser praticadas enquanto se joga jogos de vídeo. Além disso, os jogos digitais permitiram que os participantes ensinassem e aprendessem com outros jogadores através da jogabilidade. Este processo foi seguido por uma análise hierárquica de agrupamento que alocou os respondentes em quatro grupos com base nas semelhanças de suas respostas

Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: The influence of zeolite chemical surface characteristics

In this study, the effect of zeolite chemical surface characteristics on the oxidative regeneration of toluene saturated-zeolite samples is investigated. A Chilean natural zeolite (53% clinoptilolite, 40% mordenite and 7% quartz) was chemically modified by acid treatment with hydrochloric acid and by ion-exchange with ammonium sulphate. Thermal pre-treatments at 623 and 823 K were applied and six zeolite samples with different chemical surface characteristics were generated. Chemical modification of natural zeolite followed by thermal out-gassing allows distinguishing the role of acidic surface sites on the regeneration of exhausted zeolites. An increase in Brønsted acid sites on zeolite surface is observed as a result of ammonium-exchange treatment followed by thermal treatment at 623 K, thus increasing the adsorption capacity toward toluene. High ozone consumption could be associated to a high content of Lewis acid sites, since these could decompose ozone into atomic active oxygen species. Then, surface oxidation reactions could take part among adsorbed toluene at Brønsted acid sites and surface atomic oxygen species, reducing the amount of adsorbed toluene after the regenerative oxidation with ozone. Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity

Catalytic Ozonation of Toluene Using Chilean Natural Zeolite: The Key Role of Brønsted and Lewis Acid Sites

The influence of surface physical-chemical characteristics of Chilean natural zeolite on the catalytic ozonation of toluene is presented in this article. Surface characteristics of natural zeolite were modified by acid treatment with hydrochloric acid and ion-exchange with ammonium sulphate. Prior to catalytic ozonation assays, natural and chemically modified zeolite samples were thermally treated at 623 and 823 K in order to enhance Brønsted and Lewis acid sites formation, respectively. Natural and modified zeolite samples were characterised by N2 adsorption at 77 K, elemental analysis, X-ray fluorescence, and Fourier transform infrared (FTIR) spectroscopy, using pyridine as a probe molecule. The highest values of the reaction rate of toluene oxidation were observed when NH4Z1 and 2NH4Z1 zeolite samples were used. Those samples registered the highest density values of Lewis acid sites compared to other samples used here. Results indicate that the presence of strong Lewis acid sites at the 2NH4Z1 zeolite surface causes an increase in the reaction rate of toluene oxidation, confirming the role of Lewis acid sites during the catalytic ozonation of toluene at room temperature. Lewis acid sites decompose gaseous ozone into atomic oxygen, which reacts with the adsorbed toluene at Brønsted acid sites. On the other hand, no significant contribution of Brønsted acid sites on the reaction rate was registered when NH4Z1 and 2NH4Z1 zeolite samples were use