993 research outputs found
Zinc distribution and speciation in Arabidopsis halleri x Arabidopsis lyrata progenies presenting various zinc accumulation capacities
The definitive version is available at http://www.blackwell-synergy.com/loi/nphInternational audienceThe purpose of this study was to investigate the relationship between the chemical form and localization of zinc (Zn) in plant leaves and their Zn accumulation capacity. * An interspecific cross between Arabidopsis halleri sp. halleri and Arabidopsis lyrata sp. petrea segregating for Zn accumulation was used. Zinc (Zn) speciation and Zn distribution in the leaves of the parent plants and of selected F1 and F2 progenies were investigated by spectroscopic and microscopic techniques and chemical analyses. * A correlation was observed between the proportion of Zn being in octahedral coordination complexed to organic acids and free in solution (Zn-OAs + Znaq) and Zn content in the leaves. This pool varied between 40% and 80% of total leaf Zn depending on the plant studied. Elemental mapping of the leaves revealed different Zn partitioning between the veins and the leaf tissue. The vein : tissue fluorescence ratio was negatively correlated with Zn accumulation. * The higher proportion of Zn-OAs + Znaq and the depletion of the veins in the stronger accumulators are attributed to a higher xylem unloading and vacuolar sequestration in the leaf cells. Elemental distributions in the trichomes were also investigated, and results support the role of carboxyl and â or hydroxyl groups as major Zn ligands in these cells
The birds of the Loyalty Islands (New Caledonia): census, ecological and biogeographical issues
The avifauna of the Loyalty Islands comprises 62 species, including 14 breeding or
erratic seabirds, 5 migratory birds, 7 herons, ducks and rails, 4 birds of prey, 28 indigenous land breeders
(belonging to 33 subspecies) and 2 species introduced from the Grande Terre (main island of New
Caledonia). Six species are endemic: 3 on the Grande Terre and in the Loyalty Islands (New Caledonian
Friarbird Philemon diemenensis, Green-backed White-eye Zosterops xanthochrous, Striated Starling
Aplonis striatus) and 3 only found in the Loyalty Islands (Ouvea Parakeet Eunymphicus uvaeensis,
Large Lifou White-eye Zosterops inornatus and Small Lifou White-eye Z. minutus). Eunymphicus is an
endemic genus of New Caledonia. Eight subspecies are endemic to both the Grande Terre and the
Loyalty Islands and 11 are exclusive of the Loyalty Islands. Of the 24 taxa whose geographical origin
could be identified, 58% are identical or similar to those on the Grande Terre, 105 km away, and 42%
have affinities with birds in Vanuatu, twice as far away (225 km). The paths of cyclones could explain
the specific influence of Vanuatu. The correlation between the islandsâland area and the number of species
that have successfully settled is very close (r = 0.97) and confirms this biogeographical standard.
The land breeding species frequencies vary, with rare localized species limited to some islands (Bluefaced
Parrotfinch Erythrura trichroa, Ouvea Parakeet), or possibly extinct (Island Thrush Turdus poliocephalus)
and others whose frequency varies widely from place to place (Fan-tailed Cuckoo Cacomantis
flabelliformis, Gerygone Gerygone flavolateralis, Silvereye Zosterops lateralis), while others show
high (Red-bellied Fruit-Dove Ptilinopus greyii), average (Melanesian Flycatcher Myiagra caledonica,
Sacred Kingfischer Todiramphus sanctus) or low (Emerald Dove Chalcophaps indica) frequencies that
remain comparable between these islands. The species ecology has been determined with some species
associated with wide forests, e.g. the Ouvea Parakeet, while others are typical of the open settings. The
threats onto this avifauna are mainly linked to habitat destruction and the impact of introduced species.
A specific effort should be made to ensure the protection of populations of that species for which there
is the greatest concern, i.e. the Ouvea ParakeetL'avifaune des Loyauté comprend 62 espÚces, dont 14 marines nicheuses ou erratiques, 5 migratrices, 7 hérons, canards et rùles, 4 rapaces/chouette, 28 oiseaux terrestres nicheurs indigÚnes (appartenant à 33 sous-espÚces) et 2
espÚces introduites de Grande Terre. Six espÚces sont endémiques à l'archipel néo-calédonien: 3 présentes à la fois en Grande Terre et aux Loyauté: Polochion moine Philemon diemenensis, Zostérops à dos vert Zosterops xanthochrous, Stourne des Loyauté Aplanis striatus et 3 pour les seules
Loyauté: Perruche d'Ouvéa Eunymphicus uvaeensis, Zostérops de Lifou Zosterops inornatus et Zostérops minute Z. minutus. Eunymphicus est un genre endémique de Nouvelle-Calédonie. Huit sous-espÚces sont endémiques à la fois de Grande Terre et des Loyauté et 11 sont exclusives des Loyauté. Sur
24 taxons dont l'origine gĂ©ographique peut ĂȘtre Ă©tablie, 58 % sont identiques ou proches de ceux de Grande Terre distante de 105 km, et 42 % ont des affinitĂ©s avec des oiseaux du Vanuatu, deux fois plus Ă©loignĂ© (225 km). La trajectoire des cyclones pourrait expliquer cette influence
ni-vanuatu particuliÚre. La corrélation entre la surface des ßles et le nombre d'espÚces qui y ont réussi leur implantation est trÚs étroite (r = 0,97) et vérifie bien cette rÚgle de la biogéographie. La fréquence des espÚces terrestres nicheuses est variable, avec des espÚces rares et
localisĂ©es, limitĂ©es Ă certaines Ăźles (Diamant de Kittlitz Erythrura trichroa, Perruche d'OuvĂ©a) et qui ont peut-ĂȘtre disparu (Merle des Iles Turdus poliocephalus), d'autres dont la frĂ©quence est trĂšs inĂ©galement rĂ©partie (Coucou Ă Ă©ventail Cacomantis flabelliformis, GĂ©rygone Gerygone
flavolateralis, Zostérops à dos noir Zosterops lateralis), d'autres enfin aux fréquences élevées (Ptilope de Grey Ptilinopus greyii), moyennes (Monarque Myiagra caledonica, Martin-chasseur Todiramphus sanctus) ou faibles (Colombine turvert Chalcophaps indica), mais comparables entre les
Ăźles. L'Ă©cologie des espĂšces a pu ĂȘtre prĂ©cisĂ©e avec des espĂšces infĂ©odĂ©es aux grandes forĂȘts, parmi lesquelles la Perruche d'OuvĂ©a, et des espĂšces typiques des milieux ouverts. Les menaces pesant sur cette avifaune sont essentiellement liĂ©es aux destructions d'habitat et Ă l'impact des
espĂšces introduites. Un effort particulier doit ĂȘtre consenti pour sĂ©curiser les populations de l'espĂšce dont le statut est le plus prĂ©occupant: la Perruche d'OuvĂ©a
DĂ©termination de lâaction de lâacide monobromacĂ©tique administrĂ© par voie intraveineuse sur lâĂ©lectrocardiogramme du Chien
Darraspen Ernest Vincent, Jean-Blain Marcel, Florio RenĂ©, Manceau Pierre, Guedot A. DĂ©termination de lâaction de lâacide monobromacĂ©tique administrĂ© par voie intraveineuse sur lâĂ©lectro-cardiogramme du Chien. In: Bulletin de l'AcadĂ©mie VĂ©tĂ©rinaire de France tome 106 n°9, 1953. pp. 487-489
Morphology and photochemical stability of P3HT:PCBM active layers of organic solar cells
Near-to mid-IR spectral purity transfer with a tunable frequency comb: methanol frequency metrology over a record frequency span
We report the development and operation of a frequency-comb-assisted
high-resolution mid-infrared molecular spectrometer combining high spectral
purity, SI-traceability, wide tunability and high sensitivity. An optical
frequency comb is used to transfer the spectral purity of a SI-traceable 1.54
m metrology-grade frequency reference to a 10.3 m quantum cascade
laser (QCL). The near-infrared reference is operated at the French
time/frequency metrology institute, calibrated there to primary frequency
standards, and transferred to Laboratoire de Physique des Lasers via the
REFIMEVE fiber network. The QCL exhibits a sub-10 --15 frequency stability from
0.1 to 10 s and its frequency is traceable to the SI with a total uncertainty
better than 4 x 10 --14 after 1-s averaging time. We have developed the
instrumentation allowing comb modes to be continuously tuned over 9 GHz
resulting in a QCL of record spectral purity uninterruptedly tunable at the
precision of the reference over an unprecedented span of 1.4 GHz. We have used
our apparatus to conduct sub-Doppler spectroscopy of methanol in a multi-pass
cell, demonstrating state-of-art frequency uncertainties down to the few
kilohertz level. We have observed weak intensity resonances unreported so far,
resolved subtle doublets never seen before and brought to light discrepancies
with the HITRAN database. This demonstrates the potential of our apparatus for
probing subtle internal molecular processes, building accurate spectroscopic
models of polyatomic molecules of atmospheric or astrophysical interest, and
carrying out precise spectroscopic tests of fundamental physics
Syntectonic mobility of supergene nickel ores of New Caledonia (Southwest Pacific). Evidence from faulted regolith and garnierite veins.
International audienceSupergene nickel deposits of New Caledonia that have been formed in the Neogene by weathering of obducted ultramafic rocks are tightly controlled by fracture development. The relationship of tropical weathering and tectonic structures, faults and tension gashes, have been investigated in order to determine whether fractures have play a passive role only, as previously thought; or alternatively, if brittle tectonics was acting together with alteration. From the observation of time-relationship, textures, and mineralogy of various fracture fills and fault gouges, it may be unambiguously established that active faulting has play a prominent role not only in facilitating drainage and providing room for synkinematic crystallisation of supergene nickel silicate, but also in mobilising already formed sparse nickel ore, giving birth to the very high grade ore nicknamed "green gold"
Commodity risk assessment of specified species of Lonicera potted plants from Turkey
The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in the Commission Implementing Regulation (EU) 2018/2019 as âHigh-risk plants, plant products and other objectsâ. This Scientific Opinion covers plant health risks posed by potted plants (2â4 years old) of specified Lonicera species produced in nurseries and that are imported from Turkey, taking into account the available scientific information, including the technical information provided by the NPPO of Turkey. The relevance of any pest for this Opinion was based on evidence following defined criteria listed in Section 4.1. Three species, the EU-quarantine pests Lopholeucaspis japonica and Meloidogyne chitwoodi and the protected zone quarantine pest Bemisia tabaci, fulfilled these criteria and were selected for further evaluation. For these pests, the risk mitigation measures proposed in the technical dossier from Turkey were evaluated taking into account the possible limiting factors. For these pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The estimated degree of pest freedom varies among the pests evaluated, with B. tabaci on evergreen species of Lonicera spp. being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,293 and 10,000 plants per 10,000 would be free of B. tabaci
Characterization and physical modeling of endurance in embedded non-volatile memory technology
Transient and endurance mechanisms in highperformance embedded non-volatile memory flash devices are investigated in detail. An extraction methodology combining measurements on equivalent transistors and flash cells is proposed to discriminate the effects of defects on program/erase (P/E) efficiencies and on DC characteristics. A semi-analytical multiphonon-assisted charge trapping model is used to investigate the role and the impact of trapped charges on channel hotelectron injection and Fowler-Nordheim efficiencies, threshold voltage variations and endurance characteristics. © 2011 IEEE
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