The ground-based solar observations database BASS 2000

BASS 2000 is the French solar database for ground-based instruments. We describe hereafter our organization, our tasks and the products we can deliver to the international community. Our prospects cover data mining into the THeMIS archive, a participation to the EST endeavour and the creation and curation of the ESPaDOnS/NARVAL stellar spectra database.Comment: 3 pages, 1 figure (to appear in the Procs. of Solar Polarization Workshop #5, eds. Berdyugina, Nagendra and Ramelli

Espace et échelle du mouvement : la loi de Fitts dans le monde physique et dans les mondes électroniques

Nous avons conçu et mis en oeuvre une approche nouvelle du paradigme classique du pointage faisant jouer un rôle central à la variable d’échelle. Nous utilisons le diagramme espace-échelle introduit par Furnas et Bederson (1995) dans le champ de l’interaction homme-machine (IHM). Fondé sur une géométrie inédite, ce type de représentation permet de visualiser les variations d’échelle en même temps que les déplacements dans l’espace, ce qui nous a permis d’analyser la cinématique de la navigation au sein des mondes électroniques multi-échelle (ou zoomables). Les travaux rapportés dans ce document se développent autour de la frontière qui sépare le monde réel et les mondes d’information. Le monde réel dans lequel s’inscrivent normalement nos mouvements est typiquement dynamique : il met en jeu la masse, la longueur et le temps. En revanche, les mondes d’information auxquels les humains sont exposés depuis à peine deux décennies sont d’essence purement cinématique, en ce sens qu’ils ignorent typiquement la masse, et donc les contraintes de force, d’énergie et de puissance. C’est la nature cinématique des mondes d’information qui explique que leurs contenus soient indéfiniment rescalables, propriété dont les objets du monde physique ne jouissent que dans une étroite mesure, comme on le sait depuis Galilée

The design and evaluation of a sonically enhanced tool palette

This paper describes an experiment to investigate the effectiveness of adding sound to tool palettes. Palettes have usability problems because users need to see the information they present, but they are often outside the area of visual focus. We used nonspeech sounds called earcons to indicate the current tool and when tool changes occurred so that users could tell what tool they were in wherever they were looking. Results showed a significant reduction in the number of tasks performed with the wrong tool. Therefore, users knew what the current tool was and did not try to perform tasks with the wrong one. All of this was not at the expense of making the tool palettes any more annoying to use

Piezoelectric and optical setup to measure an electrical field: Application to the longitudinal near-field generated by a tapered coax

We propose a new setup to measure an electrical field in one direction. This setup is made of a piezoelectric sintered lead zinconate titanate film and an optical interferometric probe. We used this setup to investigate how the shape of the extremity of a coaxial cable influences the longitudinal electrical near-field generated by it. For this application, we designed our setup to have a spatial resolution of 100 um in the direction of the electrical field. Simulations and experiments are presented

Observations sur le cycle du detérminisme de la production chez la Vigne à l'occasion de la mise au point d'une méthode d'infection artificielle par le mildiou (Plasmopara viticola) pour l'évaluation des fongicides au champ

L'étude biométrique d'un essai destine à la mise au point d'une méthode d'appreciation de la valeur de produits fongicides (anti-mildiou), montre que la technique de brumisation permet de faire des essais valides même dans des conditions climatiques peu propices au mildiou car on obtient une infection sévère et uniforme, et l'ordre de classement des produits est sensiblement Je meme qu'en conditions naturelles.Les plantes ayant subi des destructions du feuillage très diverses suivant les traitements on été étudiées pendant trois ans. Cette étude démontre l'existence du cycle de trois ans: constitution de réserves, initiation florale, production de grappes déjà postulé par ailleurs.Observations on the cycle determining the yield of the grapevine made while perfecting a method of artificial infection by mildew (Plasmopara viticola) in order to evaluate fungicides in the fieldSpraying a water mist ("brumisation") during the summer months results in a strong and even downy mildew infection on one year old rooted vine cuttings grown in the field. This makes comparative trials of fungicides possible even in unfavourable (dry) years.Such a trial, involving four levels (spray formulations) of the fungicides factor, two levels (with or without) of the mist factor, with five replications in plots of six plants, resulted in a set of plants having suffered various degrees of foliage destruction. Measuring these plants during three successive years, starting with the differential treatment year, provided the basis for checking an hypothesis on the determination of yield in the grapevine.Progressive analysis of variance of regressions (WooLF 1951) was used in the interpretation of results.Vigour in the second year was negatively correlated with foliar damage in the first year. In turn, number of bunches in the third year was correlated with vigour in the second year, hence with foliar damage in the first year.This lends support to the hypothesis that, in the grapevine, there is a three year cycle leading to the harvested clusters.On an adult plant, three cycles are simultaneously at work at every moment. These cycles are competing for energy fixed by photosynthesls; hormonal correlations that may be correlated with energy (carbohydrates) storage, for instance through its influence on root system volume, are also at play.The implications of these results, especially for experimental work with the grapevine, are discussed

Keck Observatory Laser Guide Star Adaptive Optics Discovery and Characterization of a Satellite to the Large Kuiper Belt Object 2003 EL_(61)

The newly commissioned laser guide star adaptive optics system at Keck Observatory has been used to discover and characterize the orbit of a satellite to the bright Kuiper Belt object 2003 EL_(61). Observations over a 6 month period show that the satellite has a semimajor axis of 49,500 ± 400 km, an orbital period of 49.12 ± 0.03 days, and an eccentricity of 0.050 ± 0.003. The inferred mass of the system is (4.2 ± 0.1) × 10^(21) kg, or ~32% of the mass of Pluto and 28.6% ± 0.7% of the mass of the Pluto-Charon system. Mutual occultations occurred in 1999 and will not occur again until 2138. The orbit is fully consistent neither with one tidally evolved from an earlier closer configuration nor with one evolved inward by dynamical friction from an earlier more distant configuration

Forces on Dust Grains Exposed to Anisotropic Interstellar Radiation Fields

Grains exposed to anisotropic radiation fields are subjected to forces due to the asymmetric photon-stimulated ejection of particles. These forces act in addition to the ``radiation pressure'' due to absorption and scattering. Here we model the forces due to photoelectron emission and the photodesorption of adatoms. The ``photoelectric'' force depends on the ambient conditions relevant to grain charging. We find that it is comparable to the radiation pressure when the grain potential is relatively low and the radiation spectrum is relatively hard. The calculation of the ``photodesorption'' force is highly uncertain, since the surface physics and chemsitry of grain materials are poorly understood at present. For our simple yet plausible model, the photodesorption force dominates the radiation pressure for grains with size >~0.1 micron exposed to starlight from OB stars. We find that the anisotropy of the interstellar radiation field is ~10% in the visible and ultraviolet. We estimate size-dependent drift speeds for grains in the cold and warm neutral media and find that micron-sized grains could potentially be moved across a diffuse cloud during its lifetime.Comment: LaTeX(41 pages, 19 figures), submitted to Ap