80 research outputs found
The composition of the protosolar disk and the formation conditions for comets
Conditions in the protosolar nebula have left their mark in the composition
of cometary volatiles, thought to be some of the most pristine material in the
solar system. Cometary compositions represent the end point of processing that
began in the parent molecular cloud core and continued through the collapse of
that core to form the protosun and the solar nebula, and finally during the
evolution of the solar nebula itself as the cometary bodies were accreting.
Disentangling the effects of the various epochs on the final composition of a
comet is complicated. But comets are not the only source of information about
the solar nebula. Protostellar disks around young stars similar to the protosun
provide a way of investigating the evolution of disks similar to the solar
nebula while they are in the process of evolving to form their own solar
systems. In this way we can learn about the physical and chemical conditions
under which comets formed, and about the types of dynamical processing that
shaped the solar system we see today.
This paper summarizes some recent contributions to our understanding of both
cometary volatiles and the composition, structure and evolution of protostellar
disks.Comment: To appear in Space Science Reviews. The final publication is
available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-
Diversity of functional traits of fleshy fruits in a species-rich Atlantic rain forest
Forty years on and still going strong: the use of hominin-cercopithecid comparisons in palaeoanthropology
Détection de transgènes dans les aliments issus de plantes transgéniques
National audienc
La filiere ble dur-pates alimentaires : apports complementaires de la technologie et de la genetique dans l'amelioration de la qualite
National audienc
La PCR quantitative en temps réel : application à la quantification des OGM
24 ref.National audienc
Plant lipid transfer proteins: Relationships between allergenicity and structural, biological and technological properties
82 ref.International audienc
Quantification of common wheat adulteration of durum wheat pasta using real-time quantitative polymerase chain reaction (PCR)
International audienc
Optiques multicouches pour l'extrême UV
Nous présentons les principaux
développements réalisés dernièrement en optique multicouches
dans la gamme 30-50 nm. Autour de 30 nm, nous avons développé des
multicouches à bande passante étroite dans le but de
sélectionner une harmonique dans un spectre de source à
génération d'harmonique d'ordre élevée. Dans cette même
gamme spectrale, nous avons étudié des structures périodiques,
à trois matériaux par période, qui permettent d'augmenter de
manière significative la réflectivité. Enfin, pour les longueur
d'onde plus importante (autour de 45 nm) nous avons étudié les
performances et la stabilité de multicouches à base de scandium :
Si/Sc et Si/X/Sc/X ou X représente une couche barrière
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