Will present day glacier retreat increase volcanic activity? Stress induced by recent glacier retreat and its effect on magmatism at the Vatnajokull ice cap, Iceland

Global warming causes retreat of ice caps and ice sheets. Can melting glaciers trigger increased volcanic activity? Since 1890 the largest ice cap of Iceland, Vatnajokull, with an area of similar to 8000 km(2), has been continuously retreating losing about 10% of its mass during last century. Present-day uplift around the ice cap is as high as 25 mm/yr. We evaluate interactions between ongoing glacio-isostasy and current changes to mantle melting and crustal stresses at volcanoes underneath Vatnajokull. The modeling indicates that a substantial volume of new magma, similar to 0.014 km(3)/yr, is produced under Vatnajokull in response to current ice thinning. Ice retreat also induces significant stress changes in the elastic crust that may contribute to high seismicity, unusual focal mechanisms, and unusual magma movements in NW-Vatnajokull

Organ Transplantation in Medical and Legal Perspectives

A modeling framework for the class of piecewise linear switched systems is presented. Methods for abstraction using conservative discrete approximations are introduced and model checking is used for verifying specifications. A fairly complex example is treated, the main result being that abstraction is a promising tool for fully automated verification

The FlowSimulator framework for massively parallel CFD applications

In this paper the FlowSimulator framework for multi- disciplinary computational fluid dynamics simulations on high performance computer platforms is described. An overview of the provided functionality is given and possible benefits for tool developers as well as design engineers are presented

Differential growth of wrinkled biofilms

Biofilms are antibiotic-resistant bacterial aggregates that grow on moist surfaces and can trigger hospital-acquired infections. They provide a classical example in biology where the dynamics of cellular communities may be observed and studied. Gene expression regulates cell division and differentiation, which affect the biofilm architecture. Mechanical and chemical processes shape the resulting structure. We gain insight into the interplay between cellular and mechanical processes during biofilm development on air-agar interfaces by means of a hybrid model. Cellular behavior is governed by stochastic rules informed by a cascade of concentration fields for nutrients, waste and autoinducers. Cellular differentiation and death alter the structure and the mechanical properties of the biofilm, which is deformed according to Foppl-Von Karman equations informed by cellular processes and the interaction with the substratum. Stiffness gradients due to growth and swelling produce wrinkle branching. We are able to reproduce wrinkled structures often formed by biofilms on air-agar interfaces, as well as spatial distributions of differentiated cells commonly observed with B. subtilis.Comment: 19 pages, 13 figure

Bank intermediation and persistent liquidity effects in the presence of a frictionless bond market

An “expansionary” monetary policy that increases the growth rate of bank reserves is generally believed by policy makers to induce a “liquidity effect”, or a persistent decline in short-term nominal interest rates, that stimulates real activity. Christiano, et al. (1991,1995,1997) have incorporated this feature of the economy into equilibrium business cycle models by introducing a commercial bank that acquires deposits from households and channels those funds to firms, which use them to fund their working capital expenses. Bank deposits are the only interest-bearing financial asset available to households, and bank loans are the only source of working capital finance available to firms. To obtain a liquidity effect in response to an unanticipated reserves injection, those models rely on an information friction whereby households precommit to a liquid asset position prior to the monetary shock. In practice, the capital markets are a major source of working capital finance, and U.S. data indicate that bank financing as a share of total short-term working capital finance is countercyclical. This paper extends this literature by introducing a bond market that allows for nonintermediated loans directly from households to firms, and examines the information friction that could induce liquidity effects and countercyclicality in the degree of bank intermediation of working capital finance. The results indicate: (i) “sticky prices” are neither necessary nor sufficient to induce a liquidity effect; (ii) deposit precommitment by households along with a presetting of the deposit rate by banks does induce persistent liquidity effects, but results in excess volatility of consumption and investment; (iii) minimizing the deposit precommitment, while maintaining the preset deposit rate induces a weaker liquidity effect that is more in line with the data, without the excess volatility in consumption and investment; and (iv) the share of bank intermediation in working capital finance is countercyclical in all cases, including the absence of an information friction.Bonds ; Liquidity (Economics) ; Banks and banking

Fermions on Non-Trivial Topologies

An exact expression for the Green function of a purely fermionic system moving on the manifold $\Re \times \Sigma^{D-1}$, where $\Sigma^{D-1}$ is a $(D-1)$-torus, is found. This expression involves the bosonic analog of $\chi_n = e^{in\theta}$ corresponding to the irreducible representation for the n-th class of homotopy and in the fermionic case for D=2 and 3, $\chi_n$ is a measure of the statistics of the particles. For higher dimensions ($D \geq 4$), there is no analogue interpretation however this could, presumably, indicate a generation of mass as in quantum field theories at finite temperature.Comment: Some portions re-written, references added. To appear in PL