Correlations of a bound interface over a random substrate

The correlation function of a one-dimensional interface over a random substrate, bound to the substrate by a pressure term, is studied by Monte-Carlo simulation. It is found that the height correlation , averaged over the substrate disorder, fits a form exp(-(j/b)^c) to a surprising precision in the full range of j where the correlation is non-negligible. The exponent c increases from 1.0 to 1.5 when the interface tension is taken larger and larger.Comment: 7 pages, 5 figure

Dynamics of a driven probe molecule in a liquid monolayer

We study dynamics of a probe molecule, driven by an external constant force in a liquid monolayer on top of solid surface. In terms of a microscopic, mean-field-type approach, we calculate the terminal velocity of the probe molecule. This allows us to establish the analog of the Stokes formula, in which the friction coefficient is interpreted in terms of the microscopic parameters characterizing the system. We also determine the distribution of the monolayer particles as seen from the stationary moving probe molecule and estimate the self-diffusion coefficient for diffusion in a liquid monolayer.Comment: Latex, 7 pages, 1 figur

A necklace of Wulff shapes

In a probabilistic model of a film over a disordered substrate, Monte-Carlo simulations show that the film hangs from peaks of the substrate. The film profile is well approximated by a necklace of Wulff shapes. Such a necklace can be obtained as the infimum of a collection of Wulff shapes resting on the substrate. When the random substrate is given by iid heights with exponential distribution, we prove estimates on the probability density of the resulting peaks, at small density

La vallée de l'Escaut à Pont-à-Chin

The sudden opening of a karst pipe in the abandoned bed of the Scheldt River has exposed 8 m ofHolocene deposits; their stratigraphy, archaeological contents, fossil fauna and flora are studied here. A well dated early occupation is from the First Iron Age to Early La Tène (around 650-450 B.C.), a second one from Roman times (around 50-200 A.D.); they permit a close control of the14 C dates, which are systematically too old, due to reworking in the stream. Vertebrate and molluscan assemblages are discussed separatel

Micropalaeontological dating of the Prémontré mammal fauna (MP10, Prémontré Sands, EECO, early late Ypresian, Paris Basin)

At their type locality the Prémontré Sands contain fairly well-diversified organic-walled microfossil assemblages attributable to the lower part of dinoflagellate cyst Zone D9 and indicating a transition from an estuarine to a lagoonal depositional regime, up-section as well as laterally. Identical assemblages have been recorded in the inner to mid-neritic Merelbeke Clay Member in Belgium, allowing the Prémontré Sands to be positioned within lower NP13 and early Chron C22r. The deposition of the MP10 Prémontré mammal fauna is estimated to postdate the onset of both NP13 and Chron C22r, which are nearly coincident, by about 200 to 300 kyr. The biostratigraphic dating refers this deposit to the early late Ypresian and to the final phase of the Early Eocene Climatic Optimum (EECO) at about 50.4 to 50.3 million years ago. The Prémontré Sands, as well as their distal equivalent the Merelbeke Clay Member, were deposited following a major sea-level rise, the highest of the late Ypresian in the southern North Sea Basin s.l. (including the Paris Basin). They are separated from the overlying “Glauconie grossière” (zone NP14; middle part of zone D9) by a hiatus of approximately 2.5 myr

Microfossiles a paroi organique de l'ypresien inferieur a quenast

Twohundred and fortyeight species of organic walled micro- fossils, with among them seven new species, were found in the Sands of Oostende-ter-Streep, the Clay of leper, the Sands of Mons-en-Pevele and the Clay of Merelbeke in the Belgian basin. The assemblages of the marine Ypresian deposits are rich and totally different from the very poor assemblages of the lagunar Landenian deposits. About one fourth of the species have been found, each of them, in a limited part of the sequence. Their distribution allows us to correlate Ypresian deposits of several localities in the Belgian basin with those from the reference profile of Kallo with a precision of about five to ten metres