Credit, Profitability and Instability: A Strictly Structural Approach

This paper offers a purely structural characterisation of the content, limits and contradictions of credit relations in capitalist accumulation. Considering steady-state evolutions and step-change perturbations in a dynamic model of the Marxian circuit of capital, it establishes that sustained paces of net credit extension may boost aggregate profitability, the rate of accumulation, and the aggregate financial robustness of capitalist enterprises. These gains are limited by the economy’s dynamic productive capacities, and tempered by the risks of credit and monetary disruptions created payment obligations established by credit. Economies with higher paces of net credit extension are shown to be more vulnerable to the disruptions to accumulation variously emphasised by Marxian, Keynesian and Post-Keynesian contributions.

At the Heart of the Matter: Household Debt in Contemporary Banking and the International Crisis

This paper considers the nature and role of household indebtedness in contemporary banking and the current financial and economic crises. It offers a concise empirical exposition of the centrality of household lending and related financial services to leading banking institutions and to the credit systems of a number of advanced and middle-income economies. It also offers socioeconomic characterizations of this debt and its macroeconomic significance from the standpoint of Marxist political economy, affording two distinctive insights. First, the concrete social content of household debt over the past two decades has helped ensure this lending remained highly profitable to lenders, making it a natural vehicle for destabilizing capital-market competition. Second, a crisis characterized by record levels of over-indebted wage-earning households is likely to pose distinctive difficulties to a process of market-based recovery. While the destruction of capital values during a crisis lays the basis for the eventual restoration of profitability and solvency for some enterprises, over-indebted wage-earning households face no analogous opportunity. Without new speculative asset-price bubbles, the restoration of their financial stability hinges on reductions in consumption or increases in wages, both of which present obstacles to a market-based process of economic recovery.

A NOTE ON COMONOTONICITY AND POSITIVITY OF THE CONTROL COMPONENTS OF DECOUPLED QUADRATIC FBSDE

In this small note we are concerned with the solution of Forward-Backward Stochastic Differential Equations (FBSDE) with drivers that grow quadratically in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem is a comparison result that allows comparing componentwise the signs of the control processes of two different qgFBSDE. As a byproduct one obtains conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio

Non-trivial linear bounds for a random walk driven by a simple symmetric exclusion process

Non-trivial linear bounds are obtained for the displacement of a random walk in a dynamic random environment given by a one-dimensional simple symmetric exclusion process in equilibrium. The proof uses an adaptation of multiscale renormalization methods of Kesten and Sidoravicius.Comment: 20 pages, 3 figure

Nanocrystalline cathodes for PC-SOFCs

Ceramic proton conductors are of great interest for the development of solid oxide fuel cells (PC-SOFC) operating at relatively low temperatures between 400 and 700 ºC. Perovskites based on BaCeO3-δ exhibit the highest proton conductivity among this class of materials, however, they are susceptible to hydra-tion and carbonation in presence of water vapor and CO2 [1]. In contrast, the chemical stability of BaZrO3-based protonic conductors is better, but they require sintering temperatures as high as 1700 ºC and usually suffer from high intrinsic grain boundary resistance, limiting the final performance. Partial substitution of Zr for Ce in Ba(Ce0.9-xZrx)Y0.2O3-δ allows obtaining electrolytes with both high proton conductivity and good chemical stability. The performance of a PC-SOFC at low tempe-ratures depends significantly on the ohmic resis-tance of the electrolyte, although it can be lowered by reducing the electrolyte thickness. Another im-portant limiting factor is the increase of the cathode polarization resistance due to the thermally activated nature of the oxygen reduction reaction. For this reason, it is essential to obtain high efficiency cathodes operating at reduced temperatures. In this work, BaCe0.6Zr0.2Y0.2O3-δ (BCZY) powders were prepared by freeze-drying precursor method. These powders were mixed with a Zn-containing solution as sintering additive in order to obtain dense pellets with submicrometric grain size at only 1200 ºC. After that, La0.6Sr0.4Co0.8Fe0.2O3 nanocrystalline electrodes were deposited symmet-rically onto dense pellets BCZY by conventional spray-pyrolysis [3]. The structure, microstructure and electrochemical properties of these electrodes have been examined by XRD, FE-SEM and im-pedance spectroscopy. The stability of these elec-trodes at intermediate temperatures was evaluated as a function of time. These nanocrystalline cathodes exhibit a sub-stantial improvement of the electrode polarization resistance with respect to the same materials pre-pared by screen-printing method at high sintering temperatures, e.g. 0.7 and 3.2 cm2 at 600ºC for LSCF cathodes prepared by spray-pyrolysis and screen-printing method respectively (Fig. 1). An anode supported cell with composition LSCF/BCZY/NiO-BCZY was also prepared to test the electrochemical performance.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Characteristic functions on the boundary of a planar domain need not be traces of least gradient functions

Given a smooth bounded planar domain, we construct a compact set on the boundary s.t. its characteristic function is not the trace of a least gradient function. This generalize the construction of Spradlin and Tamasan [ST14] on the disc

Introduction to Gauge Theory of Gravitation

The fundamental interactions of nature, the electroweak and the quantum chromodynamics, are described in the Standard Model by the Gauge Theory under internal symmetries that maintain the invariance of the functional action. The fundamental interaction of gravitation is very well described by Einstein's General Relativity in a Riemannian spacetime metric, but General Relativity has been over time a gravitational field theory apart from the Standard Model. The theory of Gauge allows under symmetries of the group of Poincar\'e to impose invariances in the functional of the action of the spinor field that result in the gravitational interaction with the fermions. In this approach the gravitational field, besides being described by the equation similar to General Relativity, also brings a spin-gravitational interaction in a Riemann-Cartan spacetime.Comment: 23 page