Régime alimentaire de Rupicola rupicola (Cotingidae) en Guyane française : relations avec la frugivorie et la zoochorie

The diet of the Guianan Cock-of-the-Rock (Rupicola rupicola) was studied in a pristine lowland rainforest, near an inselberg in French Guiana. Droppings were collected under a nest and observations were conducted on a radio-tagged female. Nestlings were mostly fed fruit, but not exclusively so, as insects, small snakes, and lizards were also delivered to the chicks. The characteristics of the fruits consumed, and of the fruiting plants, were given special attention. The fruit diet is highly diversified : 65 species belonging to 31 families were recorded as ingested in a little more than one month. Remains of fifty-two species belonging to 26 families were identified under the nest itself. A quantification by feeding units (representing what the bird actually takes on the plant) shows that three quarters of the diet were contributed by only a quarter of the fruit species. Two thirds of the feeding units were contributed by only four plant families. Half the number of fruit species and two thirds of the feeding units were drupes, generally 10 to 20 mm in breadth, with seeds 5-1 5 mm wide. 83 % of the fruits were uniformly coloured. Taken together, black and red fruits were three times more abundant than all the others. The pulp of more than two thirds of the fruits amounted to at least three fifths of the fruit itself. A large proportion of the fruits consumed were those of canopy trees and lianas. More than three quarters of the fruits were from plants with large simultaneous crop production. These fruits were plucked out on the wing by the adult female which patroled a home range of 9.7 ha when feeding her brood, going from one fruiting tree to another. These results are compared with the scanty littérature data on the diet of the two Rupicola species. Cocks-of-the-rocks cannot be considered as specialized frugivores, sensu Snow (1981). The assumed coevolution between cocks-of-the-rocks and plants is briefly discussed.Erard Christian, Théry Marc, Sabatier Daniel. Régime alimentaire de Rupicola rupicola(Cotingidae) en Guyane française. Relations avec la frugivorie et la zoochorie. In: Revue d'Écologie (La Terre et La Vie), tome 44, n°1, 1989. pp. 47-74

Composition of Syrtis Major volcanic plateau

Syrtis Major, a low-relief volcanic shield centered near 295 degrees 10 degrees N, is an old, well-preserved and exposed volcanic region on Mars which formed at the end of the heavy bombardment period. The composition of these volcanic materials has importance for understanding the thermal and chemical history of Mars. Imaging spectrometer data of the Syrtis Major volcanic plateau are used in this analysis to identify major compositional components. First and second order even channel reflectance spectra between 0.77 and 2.55 microns from four broad classes of materials on Syrtis Major are given. For the volcanic materials, there are three primary classes characterized by albedo, slope, and shape of the 10 micron band. To emphasize the latter, straight line continua were removed from each spectral segment and replotted in another figure. Each spectrum shows a band minima near 0.96 microns and 2.15 microns indicative of pyroxene mineral absorptions. Comparison of these band minima with studies of pyroxene reflectance spectra suggests that the pyroxenes in the volcanics of Syrtis Major are high calcium pyroxene with a Ca/(Mg+Fe+Ca) ratio of 0.2 to 0.3. The most likely pyroxene is an augite

Planetary Science Virtual Observatory architecture

In the framework of the Europlanet-RI program, a prototype of Virtual Observatory dedicated to Planetary Science was defined. Most of the activity was dedicated to the elaboration of standards to retrieve and visualize data in this field, and to provide light procedures to teams who wish to contribute with on-line data services. The architecture of this VO system and selected solutions are presented here, together with existing demonstrators

Disk-resolved spectral reflectance properties of Phobos from 0.3-3.2 micron: Preliminary integrated results from Phobos 2

The Phobos 2 mission provided multispectral observations of Phobos over a large wavelength range and with relatively high spectral resolution. Here, researchers integrate results from three multispectral detectors by determining the ultraviolet-visible near infrared spectral properties of color and brightness features recognized in VSK TV images. Researchers present evidence that there are two fundamental spectral units within the region of overlapping coverage by the detectors. They describe the units' spectral and reflectance properties and discuss the implications of these results for the composition of Phobos

On discretization in time in simulations of particulate flows

We propose a time discretization scheme for a class of ordinary differential equations arising in simulations of fluid/particle flows. The scheme is intended to work robustly in the lubrication regime when the distance between two particles immersed in the fluid or between a particle and the wall tends to zero. The idea consists in introducing a small threshold for the particle-wall distance below which the real trajectory of the particle is replaced by an approximated one where the distance is kept equal to the threshold value. The error of this approximation is estimated both theoretically and by numerical experiments. Our time marching scheme can be easily incorporated into a full simulation method where the velocity of the fluid is obtained by a numerical solution to Stokes or Navier-Stokes equations. We also provide a derivation of the asymptotic expansion for the lubrication force (used in our numerical experiments) acting on a disk immersed in a Newtonian fluid and approaching the wall. The method of this derivation is new and can be easily adapted to other cases

The EPN-TAP protocol for the Planetary Science Virtual Observatory

A Data Access Protocol has been set up to search and retrieve Planetary Science data in general. This protocol will allow the user to select a subset of data from an archive in a standard way, based on the IVOA Table Access Protocol (TAP). The TAP mechanism is completed by an underlying Data Model and reference dictionaries. This paper describes the principle of the EPN- TAP protocol and interfaces, underlines the choices that have been made, and discusses possible evolutions.Comment: 21 pages. Submitted to Astronomy & Computing, S.I. Virtual Observator

Recovery of surface reflectance spectra and evaluation of the optical depth of aerosols in the near-IR using a Monte-Carlo approach: Application to the OMEGA observations of high latitude regions of Mars

We present a model of radiative transfer through atmospheric particles based on Monte Carlo methods. This model can be used to analyze and remove the contribution of aerosols in remote sensing observations. We have developed a method to quantify the contribution of atmospheric dust in near-IR spectra of the Martian surface obtained by the OMEGA imaging spectrometer on board Mars Express. Using observations in the nadir pointing mode with significant differences in solar incidence angles, we can infer the optical depth of atmospheric dust, and we can retrieve the surface reflectance spectra free of aerosol contribution. Martian airborne dust properties are discussed and constrained from previous studies and OMEGA data. We have tested our method on a region at 90{\deg}E and 77{\deg}N extensively covered by OMEGA, where significant variations of the albedo of ice patches in the visible have been reported. The consistency between reflectance spectra of ice-covered and ice-free regions recovered at different incidence angles validates our approach. The optical depth of aerosols varies by a factor 3 in this region during the summer of Martian year 27. The observed brightening of ice patches does not result from frost deposition but from a decrease in the dust contamination of surface ice and (to a lower extent) from a decrease in the optical thickness of atmospheric dust. Our Monte Carlo-based model can be applied to recover the spectral reflectance characteristics of the surface from OMEGA spectral imaging data when the optical thickness of aerosols can be evaluated. It could prove useful for processing image cubes from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on board the Mars Reconnaissance Orbiter (MRO)