Capital Flow Controls, International Asset Pricing, and Investors' Welfare: A Multi-country Framework.

This paper investigates the impact of capital flow restrictions on the pricing of securities, on the optimal portfolio compositions of investors of different nationalities, and on their welfare. Under capital flow controls, the equilibrium price of a security is determined jointly by its international and national risk premiums, and investors acquire nationality-specific portfolios along with a market-wide proxy for the world market portfolio. Removal of investment barriers generally leads to an increase in the aggregate market value of the affected securities, and all investors favor a move toward market integration. Introduction of different types of index funds in the world market generally increases world market integration and investor welfare. Copyright 1989 by American Finance Association.

Viscosity of silicate melts from the active submarine volcanic chain of Mayotte

International audienceFollowing an unprecedented seismic activity that started in May 2018, a new volcanic edifice, now called Mont Fani Maoré, was constructed on the ocean floor 50 km east of the island of Mayotte (Indian Ocean). This volcano is the latest addition to a volcanic chain characterized by an alkaline basanite-to-phonolite magmatic differentiation trend. Here, we performed viscosity measurements on five silicate melts representative of the East-Mayotte Volcanic Chain compositional trend: two basanites from Mont Fani Maoré, one tephri-phonolite and two phonolites from different parts of the volcanic chain. A concentric cylinder viscometer was employed at super-liquidus conditions between 1500 K and 1855 K and a creep apparatus was used for measuring the viscosity of the undercooled melts close to the glass transition temperature. At super-liquidus temperatures, basanites have the lowest viscosity (0.11-0.99 log10 Pa⸱s), phonolites the highest (0.91-3.89 log10 Pa⸱s), while the viscosity of the tephr

Viscosity of silicate melts from the active submarine volcanic chain of Mayotte

International audienceFollowing an unprecedented seismic activity that started in May 2018, a new volcanic edifice, now called Mont Fani Maoré, was constructed on the ocean floor 50 km east of the island of Mayotte (Indian Ocean). This volcano is the latest addition to a volcanic chain characterized by an alkaline basanite-to-phonolite magmatic differentiation trend. Here, we performed viscosity measurements on five silicate melts representative of the East-Mayotte Volcanic Chain compositional trend: two basanites from Mont Fani Maoré, one tephri-phonolite and two phonolites from different parts of the volcanic chain. A concentric cylinder viscometer was employed at super-liquidus conditions between 1500 K and 1855 K and a creep apparatus was used for measuring the viscosity of the undercooled melts close to the glass transition temperature. At super-liquidus temperatures, basanites have the lowest viscosity (0.11-0.99 log10 Pa⸱s), phonolites the highest (0.91-3.89 log10 Pa⸱s), while the viscosity of the tephr

Viscosity of crystal-free silicate melts from the active submarine volcanic chain of Mayotte

Following an unprecedented seismic activity that started in May 2018, a new volcanic edifice, now called Fani Maoré, was constructed on the ocean floor 50 km east of the island of Mayotte (Indian Ocean). This volcano is the latest addition to a volcanic chain characterized by an alkaline basanite-to-phonolite magmatic differentiation trend. Here, we performed viscosity measurements on five silicate melts representative of the East-Mayotte Volcanic Chain compositional trend: two basanites from Fani Maoré, one tephriphonolite and two phonolites from different parts of the volcanic chain. A concentric cylinder viscometer was employed at super-liquidus conditions between 1500 K and 1855 K and a creep apparatus was used for measuring the viscosity of the undercooled melts close to the glass transition temperature in the air. At super-liquidus temperatures, basanites have the lowest viscosity (0.11–0.34 to 0.99–1.16 log10 Pa⸱s), phonolites the highest (1.75–1.91 to 3.10–3.89 log10 Pa⸱s), while the viscosity of the tephriphonolite falls in between (0.89–1.97 log10 Pa⸱s). Near the glass transition, viscosity measurements have only been performed for one phonolite melt because obtaining pure glass samples for the basanite and tephriphonolite compositions was unsuccessful. This was due to the formation of nanolites upon quench as evidenced by Raman spectroscopy. The phonolite viscosity ranges from of 10.19 log10 Pa⸱s at 1058 K to 12.30 log10 Pa⸱s at 986 K. Comparison with existing empirical models revealed an underestimation of 1.2 to 2.0 log units at super-liquidus and undercooled temperatures, respectively, for the phonolite. This emphasizes (i) the lack of data falling along the alkaline basanite-to-phonolite magmatic differentiation trend to calibrate empirical models, and (ii) the complexity of modeling viscosity variations as a function of temperature and chemical composition for alkaline compositions. The new measurements indicate that, at eruptive temperatures between 1050 °C and 1150 °C (1323–1423 K), the oxidized, anhydrous, crystal-free and bubble-free basanite melt is very fluid, presenting a viscosity around 2.6 log10 Pa⸱s. In contrast, the anhydrous phonolite crystal- and bubble-free melt would have a viscosity around 6–10 log10 Pa⸱s at expected eruptive temperatures, which range from 800 to 1000 °C (1073–1273 K). Considering that both basanite and phonolite lavas from the Mayotte submarine volcanic chain contain <6% crystals and a significant amount of water, such viscosity values are probably upper limits. The new viscosity measurements are essential to define eruptive models and to better understand the storage and transport dynamics of Comoros Archipelago magmas, and of alkaline magmas in general, from the source to the surface