A new approach of seismoelectric imaging has been recently proposed to detect saturation fronts in which seismic waves are focused in the subsurface to scan its heterogeneous nature and determine saturation fronts. Such type of imaging requires however a complete modelling of the seismoelectric properties of porous media saturated by two immiscible fluid phases, one being usually electrically i…

We introduce the Complex-Step-Finite-Difference method (CSFDM) as a generalization of the well-known Finite-Difference method (FDM) for solving the acoustic and elastic wave equations. We have found a direct relationship between modelling the second-order wave equation by the FDM and the first-order wave equation by the CSFDM in 1-D, 2-D and 3-D acoustic media. We present the numerical methodol…

We investigate the consequences of natural conjectures of Montgomery type on the non-vanishing of Dirichlet L-functions at the central point. We first justify these conjectures using probabilistic arguments. We then show using a result of Bombieri, Friedlander and Iwaniec, and a result of the author that they imply that almost all Dirichlet L-functions do not vanish at the central point. We al…

We present a strategy to thoroughly investigate the effects of prominent topography on the surface tilt due to a spherical pressure source.We use Etna’s topography as a case of study and, for different source positions, we compare the tilt fields calculated through (i) a 3-D boundary element method and (ii) analytical half-space solutions. We systematically determine (i) the source positions …

We present a rigorous method for interpolation of electric and magnetic fields close to an interface with a conductivity contrast. The method takes into account not only a well-known discontinuity in the normal electric field, but also discontinuity in all the normal derivatives of electric and magnetic tangential fields. The proposed method is applied to marine 3-D controlled…

For the first time, a deep seismic data set acquired in the frame of the Algerian–French SPIRAL program provides new insights regarding the origin of the westernmost Algerian margin and basin. We performed a tomographic inversion of traveltimes along a 100-km-long wide-angle seismic profile shot over 40 ocean bottom seismometers offshore Mostaganem (Northwestern Algeria). The resu…

Fishes are well known for their remarkable maneuverability and agility. Less visible is the continuous control of stability essential for the exploitation of the full range of aquatic resources. Perturbations to posture and trajectory arise from hydrostatic and hydrodynamic forces centered in a fish (intrinsic) and from the environment (extrinsic). Hydrostatic instabilities arise from vertical …

In this article, we examine the relationship between primary school fees and education quality and access over the past forty years in seven sub-Saharan African countries. School fees were introduced as a means for revenue-constrained governments to fund the improvement and expansion of primary education. Recently there has been a move towards their abolition. We find that the introduction of f…

Since the publication of Lawrence M. Clopper’s seminal article ‘Miracula and The Tretise of Miraclis Pleyinge’ in Speculum in 1990 followed by ‘Communitatis: The Play of Saints in Late Medieval and Tudor England’ in Mediaevalia in 1995 and then his full-length study Drama, Play and Game: English Festive Culture in the Medieval and Early Modern Period in 2001, early drama studies have …

School social workers are often on the frontline of response and recovery from a major school crisis. It is imperative that they feel prepared and display crisis intervention self-efficacy as they intervene after disaster. The purpose of this study was to explore school social worker perception of individual and school environment preparedness in relation to crisis preparation activities inclu…