EUV spectroscopy of the Venus dayglow with UVIS on Cassini

in Icarus: International Journal of Solar System Studies (2011), 211

We analyze EUV spatially-resolved dayglow spectra obtained at 0.37 nm resolution by the UVIS instrument during the Cassini flyby of Venus on 24 June 1999, a period of high solar activity level. Emissions ... [more ▼]

We analyze EUV spatially-resolved dayglow spectra obtained at 0.37 nm resolution by the UVIS instrument during the Cassini flyby of Venus on 24 June 1999, a period of high solar activity level. Emissions from OI, OII, NI, CI and CII and CO have been identified and their disc average intensity has been determined. They are generally somewhat brighter than those determined from the observations made with the HUT spectrograph at a lower activity level, We present the brightness distribution along the foot track of the UVIS slit of the OII 83.4 nm, OI 98.9 nm, Lyman-ß + OI 102.5 nm and NI 120.0 nm multiplets, and the CO C-X and B-X Hopfield-Birge bands. We make a detailed comparison of the intensities of the 834 nm, 989 nm, 120.0 nm multiplets and CO B-X band measured along the slit foot track on the disc with those predicted by an airglow model previously used to analyze Venus and Mars ultraviolet spectra. This model includes the treatment of multiple scattering for the optically thick OI, OII and NI multiplets. It is found that the observed intensity of the OII emission at 83.4 nm is higher than predicted by the model. An increase of the O[SUP]+[/SUP] ion density relative to the densities usually measured by Pioneer Venus brings the observations and the modeled values into better agreement. The calculated intensity variation of the CO B-X emission along the track of the UVIS slit is in fair agreement with the observations. The intensity of the OI 98.9 nm emission is well predicted by the model if resonance scattering of solar radiation by O atoms is included as a source. The calculated brightness of the NI 120 nm multiplet is larger than observed by a factor of ˜2-3 if photons from all sources encounter multiple scattering. The discrepancy reduces to 30-80% if the photon electron impact and photodissociation of N[SUB]2[/SUB] sources of N([SUP]4[/SUP]S) atoms are considered as optically thin. Overall, we find that the O, N[SUB]2[/SUB] and CO densities from the empirical VTS3 model provide satisfactory agreement between the calculated and the observed EUV airglow emissions. [less ▲]

Evading death by vacuum

E-print/Working paper (2012)

Quantum Mechanics and Quantum Field Theory have forced a reappraisal of the vacuum's exact nature. This is specially true in the Standard Model of particle interactions, where spontaneous symmetry ... [more ▼]

Quantum Mechanics and Quantum Field Theory have forced a reappraisal of the vacuum's exact nature. This is specially true in the Standard Model of particle interactions, where spontaneous symmetry breaking of the electroweak symmetry by the vacuum is mandatory for elementary particles to acquire masses. The mechanism implemented with one scalar doublet leads to a simple vacuum structure at current energies. But, the open possibility that there might be two scalar doublets, enriches the vacuum structure, allowing for the possibility that we might now be in a metastable state, which we dub the panic vacuum. Current experiments at LHC are probing the Higgs particle predicted as a result of the spontaneous symmetry breaking. Remarkably, these experiments may also be useful to dispel the panic vacuum, as we show in a simple model with two doublets and a softly broken U(1) symmetry. [less ▲]

Evaluación continua y examenes : manual de docimología

Book published by El Ateneo (1973)

Evaluacion del comportamiento agressivo en ninos preescolares

in Revista Galega de Psicopedagogia (1995), 12(8), 149-165

Evaluacion isocinetica de las ligamentoplastias de rodilla

in Utilidad de la reeducacion. Inflamación (1996), 7

Evaluación mediante métodos ópticos de la funcionalidad de policationes sintéticos para el enmascaramiento de sitios antigénicos en el eritrocito humano

Poster (2006, September 25)

Evaluarea continua a elevilor si examenelor manual de docimologie

Book published by Editura Pedagogica (1975)

Evaluatie van de gevolgen van de aanwezigheid van kalknodules in beton - Besluiten

Report (2010)

De oorspronkelijke verontreiniging (0.7% van het gewicht aan granulaten) is met factor 100 verminderd tijdens de productie van de granulaten en het verwerken van het beton. De maximale verontreiniging ... [more ▼]

De oorspronkelijke verontreiniging (0.7% van het gewicht aan granulaten) is met factor 100 verminderd tijdens de productie van de granulaten en het verwerken van het beton. De maximale verontreiniging geobserveerd op de werf is 0.006% van het gewicht aan granulaten. Op de werf zijn de pop-outs weinig talrijk, de kalknodules zijn klein en de pop-outs ondiep. Geen enkele scheurvorming trof het beton. Het besluit van deze studie, op basis van een worstcasescenario en met een aan zekerheid grenzende waarschijnlijkheid, is dat de verontreiniging geen risico inhoudt wat betreft duurzaamheid en stabiliteit van de werken. We bedoelen daarmee dat het risico op verlies van sterkte en het risico voor stabiliteit en duurzaamheid van structurele elementen (platen, wanden, balken) verbonden aan de aanwezigheid van nodules zo miniem zijn dat ze in feite kleiner zijn dan de risico’s ten gevolge van de normaal aanvaardbare variabiliteit van de eigenschappen van beton, in overeenstemming met de omstandigheden op de werf. Na hydratatie oefenen de verdichte portlandiet-nodules geen druk meer uit en gedragen ze zich als gewone granulaten. De risico’s verbonden aan de betonverontreiniging door kalknodules zijn dus uitsluitend esthetisch van aard en betreffen een maximale diepte van 2 tot 4 cm. [less ▲]

Evaluatie van de nieuwe dopamine-agonist CV 205-502 in de behandeling van prolactinomen

in Acta Antwerpiensia (1992), 9

Evaluating an ICT-Mediated Innovative Training Service from Users’ Perspective. An Exploratory Case Study

Conference (2008, July)

By the way of a case study, this paper aims at evaluating the innovative dimension of a training service mediated through Information and Communication Technology (ICT): the so-called e-WOCCQ. The ... [more ▼]

By the way of a case study, this paper aims at evaluating the innovative dimension of a training service mediated through Information and Communication Technology (ICT): the so-called e-WOCCQ. The originality of this article is twofold: (1) to question innovation, and (2) to consider the training more commonly as a service, whose major particularity is the implication of the user in the process. The theoretical framework emphasises on the definition of a service and on the concept of added-value. As this experience took place at the very beginning of the project development, an empirical methodology was developed. We assume that the so-called e-WOCCQ is an innovation as it represents an added value for the users. Results show that e-WOCCQ generates costs and benefits of different order, and that the ratio is influenced by factors mostly linked either with the user. Practical (improvements and targeting) and theoretical (modelisation) implications are discussed. [less ▲]