Assessing soil surface roughness decay during simulated rainfall by multifractal analysis

VIII Fórum Nacional URBANISMO E AUTARQUIAS XVI Encontro Nacional MUSEOLOGIA E AUTARQUIAS Território, Cultura, Ciência e Inclusão Batalha, Constância, 11 e 12 de Fevereiro de 2011 Sexta-Feira Dia 11 - Auditório Municipal, Batalha Sábado Dia 12 - Auditório da Casa-Memória de Camões, Constância Org. TERCUD/ FCT-462; CM Batalha; CM Constância Objectivos temáticos: Debater a presença das áreas científicas e tecnológicas no mundo do património e dos museus; Analisar a utilização dos recursos patrim..

Nonlinear Processes in Geophysics

p. 457-468Understanding and describing the spatial characteristics of soil surface microrelief are required for modelling overland flow and erosion. We employed the multifractal approach to characterize topographical point elevation data sets acquired by high resolution laser scanning for assessing the effect of simulated rainfall on microrelief decay. Three soil surfaces with different initial states or composition and rather smooth were prepared on microplots and subjected to successive events of simulated rainfall. Soil roughness was measured on a 2×2 mm2 grid, initially, i.e. before rain, and after each simulated storm, yielding a total of thirteen data sets for three rainfall sequences. The vertical microrelief component as described by the statistical index random roughness (RR) exhibited minor changes under rainfall in two out of three study cases, which was due to the imposed wet initial state constraining aggregate breakdown. The effect of cumulative rainfall on microrelief decay was also assessed by multifractal analysis performed with the box-count algorithm. Generalized dimension, Dq, spectra allowed characterization of the spatial variation of soil surface microrelief measured at the microplot scale. These Dq spectra were also sensitive to temporal changes in soil surface microrelief, so that in all the three study rain sequences, the initial soil surface and the surfaces disturbed by successive storms displayed great differences in their degree of multifractality. Therefore, Multifractal parameters best discriminate between successive soil stages under a given rain sequence. Decline of RR and multifractal parameters showed little or no association

A framework to measure integrated risk

A framework underlying various models that measure the credit risk of a portfolio is extended in this paper to allow the integration of credit risk with a range of market risks using Monte Carlo simulation. A structural model is proposed that allows interest rates to be stochastic and provides closed-form expressions for the market value of a firm's equity and its probability of default. This model is embedded within the integrated framework and the general approach illustrated by measuring the risk of a foreign exchange forward when there is a significant probability of default by the counterparty. For this example moving from a market risk calculation to an integrated risk calculation reduces the expected future value of the instrument by an amount that could not be calculated using the common pre-settlement exposure technique for estimating the credit risk of a derivative.Risk measurement, Market risk, Credit risk, Pre-settlement risk, Integrated risk, Structural credit models, Economic capital, Foreign exchange forward,

Financing Preferences of Spanish Firms: Evidence on the Pecking Order Theory

This paper analyses some of the empirical implications of the pecking order theory in the Spanish market using a panel data analysis of 1,566 firms over 1994–2000. The results show that the pecking order theory holds for most subsamples analyzed, particularly for the small and medium-sized enterprises and for the high-growth and highly leveraged companies. It is also shown that both the more and the less leveraged firms tend to converge towards more balanced capital structures. Finally, we observe that firms finance their funds flow deficits with long term debt. Copyright Springer Science + Business Media, Inc. 2005capital structure, pecking order theory,